Sample records for accurate fault location

  1. Development of an accurate transmission line fault locator using the global positioning system satellites

    NASA Technical Reports Server (NTRS)

    Lee, Harry

    1994-01-01

    A highly accurate transmission line fault locator based on the traveling-wave principle was developed and successfully operated within B.C. Hydro. A transmission line fault produces a fast-risetime traveling wave at the fault point which propagates along the transmission line. This fault locator system consists of traveling wave detectors located at key substations which detect and time tag the leading edge of the fault-generated traveling wave as if passes through. A master station gathers the time-tagged information from the remote detectors and determines the location of the fault. Precise time is a key element to the success of this system. This fault locator system derives its timing from the Global Positioning System (GPS) satellites. System tests confirmed the accuracy of locating faults to within the design objective of +/-300 meters.

  2. Cable-fault locator

    NASA Technical Reports Server (NTRS)

    Cason, R. L.; Mcstay, J. J.; Heymann, A. P., Sr.

    1979-01-01

    Inexpensive system automatically indicates location of short-circuited section of power cable. Monitor does not require that cable be disconnected from its power source or that test signals be applied. Instead, ground-current sensors are installed in manholes or at other selected locations along cable run. When fault occurs, sensors transmit information about fault location to control center. Repair crew can be sent to location and cable can be returned to service with minimum of downtime.

  3. Fault Location Based on Synchronized Measurements: A Comprehensive Survey

    PubMed Central

    Al-Mohammed, A. H.; Abido, M. A.

    2014-01-01

    This paper presents a comprehensive survey on transmission and distribution fault location algorithms that utilize synchronized measurements. Algorithms based on two-end synchronized measurements and fault location algorithms on three-terminal and multiterminal lines are reviewed. Series capacitors equipped with metal oxide varistors (MOVs), when set on a transmission line, create certain problems for line fault locators and, therefore, fault location on series-compensated lines is discussed. The paper reports the work carried out on adaptive fault location algorithms aiming at achieving better fault location accuracy. Work associated with fault location on power system networks, although limited, is also summarized. Additionally, the nonstandard high-frequency-related fault location techniques based on wavelet transform are discussed. Finally, the paper highlights the area for future research. PMID:24701191

  4. Smart intimation and location of faults in distribution system

    NASA Astrophysics Data System (ADS)

    Hari Krishna, K.; Srinivasa Rao, B.

    2018-04-01

    Location of faults in the distribution system is one of the most complicated problems that we are facing today. Identification of fault location and severity of fault within a short time is required to provide continuous power supply but fault identification and information transfer to the operator is the biggest challenge in the distribution network. This paper proposes a fault location method in the distribution system based on Arduino nano and GSM module with flame sensor. The main idea is to locate the fault in the distribution transformer by sensing the arc coming out from the fuse element. The biggest challenge in the distribution network is to identify the location and the severity of faults under different conditions. Well operated transmission and distribution systems will play a key role for uninterrupted power supply. Whenever fault occurs in the distribution system the time taken to locate and eliminate the fault has to be reduced. The proposed design was achieved with flame sensor and GSM module. Under faulty condition, the system will automatically send an alert message to the operator in the distribution system, about the abnormal conditions near the transformer, site code and its exact location for possible power restoration.

  5. Fault structure and mechanics of the Hayward Fault, California from double-difference earthquake locations

    USGS Publications Warehouse

    Waldhauser, F.; Ellsworth, W.L.

    2002-01-01

    The relationship between small-magnitude seismicity and large-scale crustal faulting along the Hayward Fault, California, is investigated using a double-difference (DD) earthquake location algorithm. We used the DD method to determine high-resolution hypocenter locations of the seismicity that occurred between 1967 and 1998. The DD technique incorporates catalog travel time data and relative P and S wave arrival time measurements from waveform cross correlation to solve for the hypocentral separation between events. The relocated seismicity reveals a narrow, near-vertical fault zone at most locations. This zone follows the Hayward Fault along its northern half and then diverges from it to the east near San Leandro, forming the Mission trend. The relocated seismicity is consistent with the idea that slip from the Calaveras Fault is transferred over the Mission trend onto the northern Hayward Fault. The Mission trend is not clearly associated with any mapped active fault as it continues to the south and joins the Calaveras Fault at Calaveras Reservoir. In some locations, discrete structures adjacent to the main trace are seen, features that were previously hidden in the uncertainty of the network locations. The fine structure of the seismicity suggest that the fault surface on the northern Hayward Fault is curved or that the events occur on several substructures. Near San Leandro, where the more westerly striking trend of the Mission seismicity intersects with the surface trace of the (aseismic) southern Hayward Fault, the seismicity remains diffuse after relocation, with strong variation in focal mechanisms between adjacent events indicating a highly fractured zone of deformation. The seismicity is highly organized in space, especially on the northern Hayward Fault, where it forms horizontal, slip-parallel streaks of hypocenters of only a few tens of meters width, bounded by areas almost absent of seismic activity. During the interval from 1984 to 1998, when digital

  6. VCSEL fault location apparatus and method

    DOEpatents

    Keeler, Gordon A [Albuquerque, NM; Serkland, Darwin K [Albuquerque, NM

    2007-05-15

    An apparatus for locating a fault within an optical fiber is disclosed. The apparatus, which can be formed as a part of a fiber-optic transmitter or as a stand-alone instrument, utilizes a vertical-cavity surface-emitting laser (VCSEL) to generate a test pulse of light which is coupled into an optical fiber under test. The VCSEL is subsequently reconfigured by changing a bias voltage thereto and is used as a resonant-cavity photodetector (RCPD) to detect a portion of the test light pulse which is reflected or scattered from any fault within the optical fiber. A time interval .DELTA.t between an instant in time when the test light pulse is generated and the time the reflected or scattered portion is detected can then be used to determine the location of the fault within the optical fiber.

  7. Discrete Wavelet Transform for Fault Locations in Underground Distribution System

    NASA Astrophysics Data System (ADS)

    Apisit, C.; Ngaopitakkul, A.

    2010-10-01

    In this paper, a technique for detecting faults in underground distribution system is presented. Discrete Wavelet Transform (DWT) based on traveling wave is employed in order to detect the high frequency components and to identify fault locations in the underground distribution system. The first peak time obtained from the faulty bus is employed for calculating the distance of fault from sending end. The validity of the proposed technique is tested with various fault inception angles, fault locations and faulty phases. The result is found that the proposed technique provides satisfactory result and will be very useful in the development of power systems protection scheme.

  8. Nonexposure Accurate Location K-Anonymity Algorithm in LBS

    PubMed Central

    2014-01-01

    This paper tackles location privacy protection in current location-based services (LBS) where mobile users have to report their exact location information to an LBS provider in order to obtain their desired services. Location cloaking has been proposed and well studied to protect user privacy. It blurs the user's accurate coordinate and replaces it with a well-shaped cloaked region. However, to obtain such an anonymous spatial region (ASR), nearly all existent cloaking algorithms require knowing the accurate locations of all users. Therefore, location cloaking without exposing the user's accurate location to any party is urgently needed. In this paper, we present such two nonexposure accurate location cloaking algorithms. They are designed for K-anonymity, and cloaking is performed based on the identifications (IDs) of the grid areas which were reported by all the users, instead of directly on their accurate coordinates. Experimental results show that our algorithms are more secure than the existent cloaking algorithms, need not have all the users reporting their locations all the time, and can generate smaller ASR. PMID:24605060

  9. Fault finder

    DOEpatents

    Bunch, Richard H.

    1986-01-01

    A fault finder for locating faults along a high voltage electrical transmission line. Real time monitoring of background noise and improved filtering of input signals is used to identify the occurrence of a fault. A fault is detected at both a master and remote unit spaced along the line. A master clock synchronizes operation of a similar clock at the remote unit. Both units include modulator and demodulator circuits for transmission of clock signals and data. All data is received at the master unit for processing to determine an accurate fault distance calculation.

  10. Contradicting Estimates of Location, Geometry, and Rupture History of Highly Active Faults in Central Japan

    NASA Astrophysics Data System (ADS)

    Okumura, K.

    2011-12-01

    Accurate location and geometry of seismic sources are critical to estimate strong ground motion. Complete and precise rupture history is also critical to estimate the probability of the future events. In order to better forecast future earthquakes and to reduce seismic hazards, we should consider over all options and choose the most likely parameter. Multiple options for logic trees are acceptable only after thorough examination of contradicting estimates and should not be a result from easy compromise or epoche. In the process of preparation and revisions of Japanese probabilistic and deterministic earthquake hazard maps by Headquarters for Earthquake Research Promotion since 1996, many decisions were made to select plausible parameters, but many contradicting estimates have been left without thorough examinations. There are several highly-active faults in central Japan such as Itoigawa-Shizuoka Tectonic Line active fault system (ISTL), West Nagano Basin fault system (WNBF), Inadani fault system (INFS), and Atera fault system (ATFS). The highest slip rate and the shortest recurrence interval are respectively ~1 cm/yr and 500 to 800 years, and estimated maximum magnitude is 7.5 to 8.5. Those faults are very hazardous because almost entire population and industries are located above the fault within tectonic depressions. As to the fault location, most uncertainties arises from interpretation of geomorphic features. Geomorphological interpretation without geological and structural insight often leads to wrong mapping. Though non-existent longer fault may be a safer estimate, incorrectness harm reliability of the forecast. Also this does not greatly affect strong motion estimates, but misleading to surface displacement issues. Fault geometry, on the other hand, is very important to estimate intensity distribution. For the middle portion of the ISTL, fast-moving left-lateral strike-slip up to 1 cm/yr is obvious. Recent seismicity possibly induced by 2011 Tohoku

  11. An automatic procedure for high-resolution earthquake locations: a case study from the TABOO near fault observatory (Northern Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Valoroso, Luisa; Chiaraluce, Lauro; Di Stefano, Raffaele; Latorre, Diana; Piccinini, Davide

    2014-05-01

    The characterization of the geometry, kinematics and rheology of fault zones by seismological data depends on our capability of accurately locate the largest number of low-magnitude seismic events. To this aim, we have been working for the past three years to develop an advanced modular earthquake location procedure able to automatically retrieve high-resolution earthquakes catalogues directly from continuous waveforms data. We use seismograms recorded at about 60 seismic stations located both at surface and at depth. The network covers an area of about 80x60 km with a mean inter-station distance of 6 km. These stations are part of a Near fault Observatory (TABOO; http://taboo.rm.ingv.it/), consisting of multi-sensor stations (seismic, geodetic, geochemical and electromagnetic). This permanent scientific infrastructure managed by the INGV is devoted to studying the earthquakes preparatory phase and the fast/slow (i.e., seismic/aseismic) deformation process active along the Alto Tiberina fault (ATF) located in the northern Apennines (Italy). The ATF is potentially one of the rare worldwide examples of active low-angle (< 15°) normal fault accommodating crustal extension and characterized by a regular occurrence of micro-earthquakes. The modular procedure combines: i) a sensitive detection algorithm optimized to declare low-magnitude events; ii) an accurate picking procedure that provides consistently weighted P- and S-wave arrival times, P-wave first motion polarities and the maximum waveform amplitude for local magnitude calculation; iii) both linearized iterative and non-linear global-search earthquake location algorithms to compute accurate absolute locations of single-events in a 3D geological model (see Latorre et al. same session); iv) cross-correlation and double-difference location methods to compute high-resolution relative event locations. This procedure is now running off-line with a delay of 1 week to the real-time. We are now implementing this

  12. Fuzzy Inference System Approach for Locating Series, Shunt, and Simultaneous Series-Shunt Faults in Double Circuit Transmission Lines

    PubMed Central

    Swetapadma, Aleena; Yadav, Anamika

    2015-01-01

    Many schemes are reported for shunt fault location estimation, but fault location estimation of series or open conductor faults has not been dealt with so far. The existing numerical relays only detect the open conductor (series) fault and give the indication of the faulty phase(s), but they are unable to locate the series fault. The repair crew needs to patrol the complete line to find the location of series fault. In this paper fuzzy based fault detection/classification and location schemes in time domain are proposed for both series faults, shunt faults, and simultaneous series and shunt faults. The fault simulation studies and fault location algorithm have been developed using Matlab/Simulink. Synchronized phasors of voltage and current signals of both the ends of the line have been used as input to the proposed fuzzy based fault location scheme. Percentage of error in location of series fault is within 1% and shunt fault is 5% for all the tested fault cases. Validation of percentage of error in location estimation is done using Chi square test with both 1% and 5% level of significance. PMID:26413088

  13. Fiber fault location utilizing traffic signal in optical network.

    PubMed

    Zhao, Tong; Wang, Anbang; Wang, Yuncai; Zhang, Mingjiang; Chang, Xiaoming; Xiong, Lijuan; Hao, Yi

    2013-10-07

    We propose and experimentally demonstrate a method for fault location in optical communication network. This method utilizes the traffic signal transmitted across the network as probe signal, and then locates the fault by correlation technique. Compared with conventional techniques, our method has a simple structure and low operation expenditure, because no additional device is used, such as light source, modulator and signal generator. The correlation detection in this method overcomes the tradeoff between spatial resolution and measurement range in pulse ranging technique. Moreover, signal extraction process can improve the location result considerably. Experimental results show that we achieve a spatial resolution of 8 cm and detection range of over 23 km with -8-dBm mean launched power in optical network based on synchronous digital hierarchy protocols.

  14. Delivery and application of precise timing for a traveling wave powerline fault locator system

    NASA Technical Reports Server (NTRS)

    Street, Michael A.

    1990-01-01

    The Bonneville Power Administration (BPA) has successfully operated an in-house developed powerline fault locator system since 1986. The BPA fault locator system consists of remotes installed at cardinal power transmission line system nodes and a central master which polls the remotes for traveling wave time-of-arrival data. A power line fault produces a fast rise-time traveling wave which emanates from the fault point and propagates throughout the power grid. The remotes time-tag the traveling wave leading edge as it passes through the power system cardinal substation nodes. A synchronizing pulse transmitted via the BPA analog microwave system on a wideband channel sychronizes the time-tagging counters in the remote units to a different accuracy of better than one microsecond. The remote units correct the raw time tags for synchronizing pulse propagation delay and return these corrected values to the fault locator master. The master then calculates the power system disturbance source using the collected time tags. The system design objective is a fault location accuracy of 300 meters. BPA's fault locator system operation, error producing phenomena, and method of distributing precise timing are described.

  15. Induction motor broken rotor bar fault location detection through envelope analysis of start-up current using Hilbert transform

    NASA Astrophysics Data System (ADS)

    Abd-el-Malek, Mina; Abdelsalam, Ahmed K.; Hassan, Ola E.

    2017-09-01

    Robustness, low running cost and reduced maintenance lead Induction Motors (IMs) to pioneerly penetrate the industrial drive system fields. Broken rotor bars (BRBs) can be considered as an important fault that needs to be early assessed to minimize the maintenance cost and labor time. The majority of recent BRBs' fault diagnostic techniques focus on differentiating between healthy and faulty rotor cage. In this paper, a new technique is proposed for detecting the location of the broken bar in the rotor. The proposed technique relies on monitoring certain statistical parameters estimated from the analysis of the start-up stator current envelope. The envelope of the signal is obtained using Hilbert Transformation (HT). The proposed technique offers non-invasive, fast computational and accurate location diagnostic process. Various simulation scenarios are presented that validate the effectiveness of the proposed technique.

  16. The complex architecture of the 2009 MW 6.1 L'Aquila normal fault system (Central Italy) as imaged by 64,000 high-resolution aftershock locations

    NASA Astrophysics Data System (ADS)

    Valoroso, L.; Chiaraluce, L.; Di Stefano, R.; Piccinini, D.; Schaff, D. P.; Waldhauser, F.

    2011-12-01

    On April 6th 2009, a MW 6.1 normal faulting earthquake struck the axial area of the Abruzzo region in Central Italy. We present high-precision hypocenter locations of an extraordinary dataset composed by 64,000 earthquakes recorded at a very dense seismic network of 60 stations operating for 9 months after the main event. Events span in magnitude (ML) between -0.9 to 5.9, reaching a completeness magnitude of 0.7. The dataset has been processed by integrating an accurate automatic picking procedure together with cross-correlation and double-difference relative location methods. The combined use of these procedures results in earthquake relative location uncertainties in the range of a few meters to tens of meters, comparable/lower than the spatial dimension of the earthquakes themselves). This data set allows us to image the complex inner geometry of individual faults from the kilometre to meter scale. The aftershock distribution illuminates the anatomy of the en-echelon fault system composed of two major faults. The mainshock breaks the entire upper crust from 10 km depth to the surface along a 14-km long normal fault. A second segment, located north of the normal fault and activated by two Mw>5 events, shows a striking listric geometry completely blind. We focus on the analysis of about 300 clusters of co-located events to characterize the mechanical behavior of the different portions of the fault system. The number of events in each cluster ranges from 4 to 24 events and they exhibit strongly correlated seismograms at common stations. They mostly occur where secondary structures join the main fault planes and along unfavorably oriented segments. Moreover, larger clusters nucleate on secondary faults located in the overlapping area between the two main segments, where the rate of earthquake production is very high with a long-lasting seismic decay.

  17. Tracer Transport Along a Vertical Fault Located in Welded Tuffs

    NASA Astrophysics Data System (ADS)

    Salve, R.; Liu, H.; Hu, Q.

    2002-12-01

    A near-vertical fault that intercepts the fractured welled tuff formation in the underground Exploratory Studies Facility (ESF) at Yucca Mountain, Nevada, has provided a unique opportunity to evaluate important hydrological parameters associated with faults (e.g., flow velocity, matrix diffusion, fault-fracture-matrix interactions). Alcove 8, which intersects the fault is located in the cross drift of the ESF, has been excavated for liquid releases through this fault and a network of fractures. Located 25 m below Alcove 8 in the main drift of the ESF, Niche 3 which also intercepts the fault, serves as the site for monitoring the wetting front and for collecting seepage following liquid releases in Alcove 8. To investigate the importance of matrix diffusion and the extent of area subject to fracture-matrix interactions, we released a mix of conservative tracers (pentafluorobenzoic acid [PFBA] and lithium bromide [LiBr]) along the fault. The ceiling of Niche 3 was blanketed with an array of trays to capture seepage, and seepage rates were continuously monitored by a water collection system connected to the trays. Additionally, a water sampling device, the passive-discreet water sampler (PDWS), was connected to three of the collections trays in Niche 3 into which water was seeping. The PDWS, designed to isolate continuous seepage from each tray into discreet samples for chemical analysis, remained connected to the trays over a period of three months. During this time, all water that seeped into the three trays was captured sequentially into sampling bottles and analyzed for concentrations of PFBA and LiBr. Water released along the fault initially traveled the 25 m vertical distance over a period of 36 days (at a velocity ~0.7 m/day). The seepage recovered in Niche 3 was less than 10% of the injected water with significant spatial and temporal fluctuations in seepage rates. Along a fast flow path, the benzoic tracer (PFBA) and LiBr were first detected ~12 days after

  18. Characterizing the structural maturity of fault zones using high-resolution earthquake locations.

    NASA Astrophysics Data System (ADS)

    Perrin, C.; Waldhauser, F.; Scholz, C. H.

    2017-12-01

    We use high-resolution earthquake locations to characterize the three-dimensional structure of active faults in California and how it evolves with fault structural maturity. We investigate the distribution of aftershocks of several recent large earthquakes that occurred on immature faults (i.e., slow moving and small cumulative displacement), such as the 1992 (Mw7.3) Landers and 1999 (Mw7.1) Hector Mine events, and earthquakes that occurred on mature faults, such as the 1984 (Mw6.2) Morgan Hill and 2004 (Mw6.0) Parkfield events. Unlike previous studies which typically estimated the width of fault zones from the distribution of earthquakes perpendicular to the surface fault trace, we resolve fault zone widths with respect to the 3D fault surface estimated from principal component analysis of local seismicity. We find that the zone of brittle deformation around the fault core is narrower along mature faults compared to immature faults. We observe a rapid fall off of the number of events at a distance range of 70 - 100 m from the main fault surface of mature faults (140-200 m fault zone width), and 200-300 m from the fault surface of immature faults (400-600 m fault zone width). These observations are in good agreement with fault zone widths estimated from guided waves trapped in low velocity damage zones. The total width of the active zone of deformation surrounding the main fault plane reach 1.2 km and 2-4 km for mature and immature faults, respectively. The wider zone of deformation presumably reflects the increased heterogeneity in the stress field along complex and discontinuous faults strands that make up immature faults. In contrast, narrower deformation zones tend to align with well-defined fault planes of mature faults where most of the deformation is concentrated. Our results are in line with previous studies suggesting that surface fault traces become smoother, and thus fault zones simpler, as cumulative fault slip increases.

  19. Precise tremor source locations and amplitude variations along the lower-crustal central San Andreas Fault

    USGS Publications Warehouse

    Shelly, David R.; Hardebeck, Jeanne L.

    2010-01-01

    We precisely locate 88 tremor families along the central San Andreas Fault using a 3D velocity model and numerous P and S wave arrival times estimated from seismogram stacks of up to 400 events per tremor family. Maximum tremor amplitudes vary along the fault by at least a factor of 7, with by far the strongest sources along a 25 km section of the fault southeast of Parkfield. We also identify many weaker tremor families, which have largely escaped prior detection. Together, these sources extend 150 km along the fault, beneath creeping, transitional, and locked sections of the upper crustal fault. Depths are mostly between 18 and 28 km, in the lower crust. Epicenters are concentrated within 3 km of the surface trace, implying a nearly vertical fault. A prominent gap in detectible activity is located directly beneath the region of maximum slip in the 2004 magnitude 6.0 Parkfield earthquake.

  20. Precise location of San Andreas Fault tremors near Cholame, California using seismometer clusters: Slip on the deep extension of the fault?

    USGS Publications Warehouse

    Shelly, D.R.; Ellsworth, W.L.; Ryberg, T.; Haberland, C.; Fuis, G.S.; Murphy, J.; Nadeau, R.M.; Burgmann, R.

    2009-01-01

    We examine a 24-hour period of active San Andreas Fault (SAF) tremor and show that this tremor is largely composed of repeated similar events. Utilizing this similarity, we locate the subset of the tremor with waveforms similar to an identified low frequency earthquake (LFE) "master template," located using P and S wave arrivals to be ???26 km deep. To compensate for low signal-to-noise, we estimate event-pair differential times at "clusters" of nearby stations rather than at single stations. We find that the locations form a near-linear structure in map view, striking parallel to the SAF and near the surface trace. Therefore, we suggest that at least a portion of the tremor occurs on the deep extension of the fault, likely reflecting shear slip, similar to subduction zone tremor. If so, the SAF may extend to the base of the crust, ???10 km below the deepest regular earthquakes on the fault. ?? 2009 by the American Geophysical Union.

  1. Fine-scale delineation of the location of and relative ground shaking within the San Andreas Fault zone at San Andreas Lake, San Mateo County, California

    USGS Publications Warehouse

    Catchings, R.D.; Rymer, M.J.; Goldman, M.R.; Prentice, C.S.; Sickler, R.R.

    2013-01-01

    The San Francisco Public Utilities Commission is seismically retrofitting the water delivery system at San Andreas Lake, San Mateo County, California, where the reservoir intake system crosses the San Andreas Fault (SAF). The near-surface fault location and geometry are important considerations in the retrofit effort. Because the SAF trends through highly distorted Franciscan mélange and beneath much of the reservoir, the exact trace of the 1906 surface rupture is difficult to determine from surface mapping at San Andreas Lake. Based on surface mapping, it also is unclear if there are additional fault splays that extend northeast or southwest of the main surface rupture. To better understand the fault structure at San Andreas Lake, the U.S. Geological Survey acquired a series of seismic imaging profiles across the SAF at San Andreas Lake in 2008, 2009, and 2011, when the lake level was near historical lows and the surface traces of the SAF were exposed for the first time in decades. We used multiple seismic methods to locate the main 1906 rupture zone and fault splays within about 100 meters northeast of the main rupture zone. Our seismic observations are internally consistent, and our seismic indicators of faulting generally correlate with fault locations inferred from surface mapping. We also tested the accuracy of our seismic methods by comparing our seismically located faults with surface ruptures mapped by Schussler (1906) immediately after the April 18, 1906 San Francisco earthquake of approximate magnitude 7.9; our seismically determined fault locations were highly accurate. Near the reservoir intake facility at San Andreas Lake, our seismic data indicate the main 1906 surface rupture zone consists of at least three near-surface fault traces. Movement on multiple fault traces can have appreciable engineering significance because, unlike movement on a single strike-slip fault trace, differential movement on multiple fault traces may exert compressive and

  2. Accurate Monitoring and Fault Detection in Wind Measuring Devices through Wireless Sensor Networks

    PubMed Central

    Khan, Komal Saifullah; Tariq, Muhammad

    2014-01-01

    Many wind energy projects report poor performance as low as 60% of the predicted performance. The reason for this is poor resource assessment and the use of new untested technologies and systems in remote locations. Predictions about the potential of an area for wind energy projects (through simulated models) may vary from the actual potential of the area. Hence, introducing accurate site assessment techniques will lead to accurate predictions of energy production from a particular area. We solve this problem by installing a Wireless Sensor Network (WSN) to periodically analyze the data from anemometers installed in that area. After comparative analysis of the acquired data, the anemometers transmit their readings through a WSN to the sink node for analysis. The sink node uses an iterative algorithm which sequentially detects any faulty anemometer and passes the details of the fault to the central system or main station. We apply the proposed technique in simulation as well as in practical implementation and study its accuracy by comparing the simulation results with experimental results to analyze the variation in the results obtained from both simulation model and implemented model. Simulation results show that the algorithm indicates faulty anemometers with high accuracy and low false alarm rate when as many as 25% of the anemometers become faulty. Experimental analysis shows that anemometers incorporating this solution are better assessed and performance level of implemented projects is increased above 86% of the simulated models. PMID:25421739

  3. Locating hardware faults in a data communications network of a parallel computer

    DOEpatents

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-01-12

    Hardware faults location in a data communications network of a parallel computer. Such a parallel computer includes a plurality of compute nodes and a data communications network that couples the compute nodes for data communications and organizes the compute node as a tree. Locating hardware faults includes identifying a next compute node as a parent node and a root of a parent test tree, identifying for each child compute node of the parent node a child test tree having the child compute node as root, running a same test suite on the parent test tree and each child test tree, and identifying the parent compute node as having a defective link connected from the parent compute node to a child compute node if the test suite fails on the parent test tree and succeeds on all the child test trees.

  4. Power flow analysis and optimal locations of resistive type superconducting fault current limiters.

    PubMed

    Zhang, Xiuchang; Ruiz, Harold S; Geng, Jianzhao; Shen, Boyang; Fu, Lin; Zhang, Heng; Coombs, Tim A

    2016-01-01

    Based on conventional approaches for the integration of resistive-type superconducting fault current limiters (SFCLs) on electric distribution networks, SFCL models largely rely on the insertion of a step or exponential resistance that is determined by a predefined quenching time. In this paper, we expand the scope of the aforementioned models by considering the actual behaviour of an SFCL in terms of the temperature dynamic power-law dependence between the electrical field and the current density, characteristic of high temperature superconductors. Our results are compared to the step-resistance models for the sake of discussion and clarity of the conclusions. Both SFCL models were integrated into a power system model built based on the UK power standard, to study the impact of these protection strategies on the performance of the overall electricity network. As a representative renewable energy source, a 90 MVA wind farm was considered for the simulations. Three fault conditions were simulated, and the figures for the fault current reduction predicted by both fault current limiting models have been compared in terms of multiple current measuring points and allocation strategies. Consequently, we have shown that the incorporation of the E - J characteristics and thermal properties of the superconductor at the simulation level of electric power systems, is crucial for estimations of reliability and determining the optimal locations of resistive type SFCLs in distributed power networks. Our results may help decision making by distribution network operators regarding investment and promotion of SFCL technologies, as it is possible to determine the maximum number of SFCLs necessary to protect against different fault conditions at multiple locations.

  5. Hydrogen atoms can be located accurately and precisely by x-ray crystallography.

    PubMed

    Woińska, Magdalena; Grabowsky, Simon; Dominiak, Paulina M; Woźniak, Krzysztof; Jayatilaka, Dylan

    2016-05-01

    Precise and accurate structural information on hydrogen atoms is crucial to the study of energies of interactions important for crystal engineering, materials science, medicine, and pharmacy, and to the estimation of physical and chemical properties in solids. However, hydrogen atoms only scatter x-radiation weakly, so x-rays have not been used routinely to locate them accurately. Textbooks and teaching classes still emphasize that hydrogen atoms cannot be located with x-rays close to heavy elements; instead, neutron diffraction is needed. We show that, contrary to widespread expectation, hydrogen atoms can be located very accurately using x-ray diffraction, yielding bond lengths involving hydrogen atoms (A-H) that are in agreement with results from neutron diffraction mostly within a single standard deviation. The precision of the determination is also comparable between x-ray and neutron diffraction results. This has been achieved at resolutions as low as 0.8 Å using Hirshfeld atom refinement (HAR). We have applied HAR to 81 crystal structures of organic molecules and compared the A-H bond lengths with those from neutron measurements for A-H bonds sorted into bonds of the same class. We further show in a selection of inorganic compounds that hydrogen atoms can be located in bridging positions and close to heavy transition metals accurately and precisely. We anticipate that, in the future, conventional x-radiation sources at in-house diffractometers can be used routinely for locating hydrogen atoms in small molecules accurately instead of large-scale facilities such as spallation sources or nuclear reactors.

  6. Hydrogen atoms can be located accurately and precisely by x-ray crystallography

    PubMed Central

    Woińska, Magdalena; Grabowsky, Simon; Dominiak, Paulina M.; Woźniak, Krzysztof; Jayatilaka, Dylan

    2016-01-01

    Precise and accurate structural information on hydrogen atoms is crucial to the study of energies of interactions important for crystal engineering, materials science, medicine, and pharmacy, and to the estimation of physical and chemical properties in solids. However, hydrogen atoms only scatter x-radiation weakly, so x-rays have not been used routinely to locate them accurately. Textbooks and teaching classes still emphasize that hydrogen atoms cannot be located with x-rays close to heavy elements; instead, neutron diffraction is needed. We show that, contrary to widespread expectation, hydrogen atoms can be located very accurately using x-ray diffraction, yielding bond lengths involving hydrogen atoms (A–H) that are in agreement with results from neutron diffraction mostly within a single standard deviation. The precision of the determination is also comparable between x-ray and neutron diffraction results. This has been achieved at resolutions as low as 0.8 Å using Hirshfeld atom refinement (HAR). We have applied HAR to 81 crystal structures of organic molecules and compared the A–H bond lengths with those from neutron measurements for A–H bonds sorted into bonds of the same class. We further show in a selection of inorganic compounds that hydrogen atoms can be located in bridging positions and close to heavy transition metals accurately and precisely. We anticipate that, in the future, conventional x-radiation sources at in-house diffractometers can be used routinely for locating hydrogen atoms in small molecules accurately instead of large-scale facilities such as spallation sources or nuclear reactors. PMID:27386545

  7. Latest Progress of Fault Detection and Localization in Complex Electrical Engineering

    NASA Astrophysics Data System (ADS)

    Zhao, Zheng; Wang, Can; Zhang, Yagang; Sun, Yi

    2014-01-01

    In the researches of complex electrical engineering, efficient fault detection and localization schemes are essential to quickly detect and locate faults so that appropriate and timely corrective mitigating and maintenance actions can be taken. In this paper, under the current measurement precision of PMU, we will put forward a new type of fault detection and localization technology based on fault factor feature extraction. Lots of simulating experiments indicate that, although there are disturbances of white Gaussian stochastic noise, based on fault factor feature extraction principal, the fault detection and localization results are still accurate and reliable, which also identifies that the fault detection and localization technology has strong anti-interference ability and great redundancy.

  8. A 3D modeling approach to complex faults with multi-source data

    NASA Astrophysics Data System (ADS)

    Wu, Qiang; Xu, Hua; Zou, Xukai; Lei, Hongzhuan

    2015-04-01

    Fault modeling is a very important step in making an accurate and reliable 3D geological model. Typical existing methods demand enough fault data to be able to construct complex fault models, however, it is well known that the available fault data are generally sparse and undersampled. In this paper, we propose a workflow of fault modeling, which can integrate multi-source data to construct fault models. For the faults that are not modeled with these data, especially small-scale or approximately parallel with the sections, we propose the fault deduction method to infer the hanging wall and footwall lines after displacement calculation. Moreover, using the fault cutting algorithm can supplement the available fault points on the location where faults cut each other. Increasing fault points in poor sample areas can not only efficiently construct fault models, but also reduce manual intervention. By using a fault-based interpolation and remeshing the horizons, an accurate 3D geological model can be constructed. The method can naturally simulate geological structures no matter whether the available geological data are sufficient or not. A concrete example of using the method in Tangshan, China, shows that the method can be applied to broad and complex geological areas.

  9. Ontology-Based Method for Fault Diagnosis of Loaders.

    PubMed

    Xu, Feixiang; Liu, Xinhui; Chen, Wei; Zhou, Chen; Cao, Bingwei

    2018-02-28

    This paper proposes an ontology-based fault diagnosis method which overcomes the difficulty of understanding complex fault diagnosis knowledge of loaders and offers a universal approach for fault diagnosis of all loaders. This method contains the following components: (1) An ontology-based fault diagnosis model is proposed to achieve the integrating, sharing and reusing of fault diagnosis knowledge for loaders; (2) combined with ontology, CBR (case-based reasoning) is introduced to realize effective and accurate fault diagnoses following four steps (feature selection, case-retrieval, case-matching and case-updating); and (3) in order to cover the shortages of the CBR method due to the lack of concerned cases, ontology based RBR (rule-based reasoning) is put forward through building SWRL (Semantic Web Rule Language) rules. An application program is also developed to implement the above methods to assist in finding the fault causes, fault locations and maintenance measures of loaders. In addition, the program is validated through analyzing a case study.

  10. Ontology-Based Method for Fault Diagnosis of Loaders

    PubMed Central

    Liu, Xinhui; Chen, Wei; Zhou, Chen; Cao, Bingwei

    2018-01-01

    This paper proposes an ontology-based fault diagnosis method which overcomes the difficulty of understanding complex fault diagnosis knowledge of loaders and offers a universal approach for fault diagnosis of all loaders. This method contains the following components: (1) An ontology-based fault diagnosis model is proposed to achieve the integrating, sharing and reusing of fault diagnosis knowledge for loaders; (2) combined with ontology, CBR (case-based reasoning) is introduced to realize effective and accurate fault diagnoses following four steps (feature selection, case-retrieval, case-matching and case-updating); and (3) in order to cover the shortages of the CBR method due to the lack of concerned cases, ontology based RBR (rule-based reasoning) is put forward through building SWRL (Semantic Web Rule Language) rules. An application program is also developed to implement the above methods to assist in finding the fault causes, fault locations and maintenance measures of loaders. In addition, the program is validated through analyzing a case study. PMID:29495646

  11. The 7.9 Denali Fault Earthquake: Aftershock Locations, Moment Tensors and Focal Mechanisms from the Regional Seismic Network Data

    NASA Astrophysics Data System (ADS)

    Ratchkovski, N. A.; Hansen, R. A.; Christensen, D.; Kore, K.

    2002-12-01

    The largest earthquake ever recorded on the Denali fault system (magnitude 7.9) struck central Alaska on November 3, 2002. It was preceded by a magnitude 6.7 foreshock on October 23. This earlier earthquake and its zone of aftershocks were located slightly to the west of the 7.9 quake. Aftershock locations and surface slip observations from the 7.9 quake indicate that the rupture was predominately unilateral in the eastward direction. Near Mentasta Lake, a village that experienced some of the worst damage in the quake, the surface rupture scar turns from the Denali fault to the adjacent Totschunda fault, which trends toward more southeasterly toward the Canadian border. Overall, the geologists found that measurable scarps indicate that the north side of the Denali fault moved to the east and vertically up relative to the south. Maximum offsets on the Denali fault were 8.8 meters at the Tok Highway cutoff, and were 2.2 meters on the Totschunda fault. The Alaska regional seismic network consists of over 250 station sites, operated by the Alaska Earthquake Information Center (AEIC), the Alaska Volcano Observatory (AVO), and the Pacific Tsunami Warning Center (PTWC). Over 25 sites are equipped with the broad-band sensors, some of which have in addition the strong motion sensors. The rest of the stations are either 1 or 3-component short-period instruments. The data from these stations are collected, processed and archived at the AEIC. The AEIC staff installed a temporary network with over 20 instruments following the 6.7 Nenana Mountain and the 7.9 events. Prior to the M 7.9 Denali Fault event, the automatic earthquake detection system at AEIC was locating between 15 and 30 events per day. After the event, the system had over 200-400 automatic locations per day for at least 10 days following the 7.9 event. The processing of the data is ongoing with the priority given to the larger events. The cumulative length of the 6.7 and 7.9 aftershock locations along the Denali

  12. Radar Determination of Fault Slip and Location in Partially Decorrelated Images

    NASA Astrophysics Data System (ADS)

    Parker, Jay; Glasscoe, Margaret; Donnellan, Andrea; Stough, Timothy; Pierce, Marlon; Wang, Jun

    2017-06-01

    Faced with the challenge of thousands of frames of radar interferometric images, automated feature extraction promises to spur data understanding and highlight geophysically active land regions for further study. We have developed techniques for automatically determining surface fault slip and location using deformation images from the NASA Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), which is similar to satellite-based SAR but has more mission flexibility and higher resolution (pixels are approximately 7 m). This radar interferometry provides a highly sensitive method, clearly indicating faults slipping at levels of 10 mm or less. But interferometric images are subject to decorrelation between revisit times, creating spots of bad data in the image. Our method begins with freely available data products from the UAVSAR mission, chiefly unwrapped interferograms, coherence images, and flight metadata. The computer vision techniques we use assume no data gaps or holes; so a preliminary step detects and removes spots of bad data and fills these holes by interpolation and blurring. Detected and partially validated surface fractures from earthquake main shocks, aftershocks, and aseismic-induced slip are shown for faults in California, including El Mayor-Cucapah (M7.2, 2010), the Ocotillo aftershock (M5.7, 2010), and South Napa (M6.0, 2014). Aseismic slip is detected on the San Andreas Fault from the El Mayor-Cucapah earthquake, in regions of highly patterned partial decorrelation. Validation is performed by comparing slip estimates from two interferograms with published ground truth measurements.

  13. Shallow-depth location and geometry of the Piedmont Reverse splay of the Hayward Fault, Oakland, California

    USGS Publications Warehouse

    Catchings, Rufus D.; Goldman, Mark R.; Trench, David; Buga, Michael; Chan, Joanne H.; Criley, Coyn J.; Strayer, Luther M.

    2017-04-18

    The Piedmont Thrust Fault, herein referred to as the Piedmont Reverse Fault (PRF), is a splay of the Hayward Fault that trends through a highly populated area of the City of Oakland, California (fig. 1A). Although the PRF is unlikely to generate a large-magnitude earthquake, slip on the PRF or high-amplitude seismic energy traveling along the PRF may cause considerable damage during a large earthquake on the Hayward Fault. Thus, it is important to determine the exact location, geometry (particularly dip), and lateral extent of the PRF within the densely populated Oakland area. In the near surface, the PRF juxtaposes Late Cretaceous sandstone (of the Franciscan Complex Novato Quarry terrane of Blake and others, 1984) and an older Pleistocene alluvial fan unit along much of its mapped length (fig. 1B; Graymer and others, 1995). The strata of the Novato Quarry unit vary greatly in strike (NW, NE, and E), dip direction (NE, SW, E, and NW), dip angle (15° to 85°), and lithology (shale and sandstone), and the unit has been intruded by quartz diorite in places. Thus, it is difficult to infer the structure of the fault, particularly at depth, with conventional seismic reflection imaging methods. To better determine the location and shallow-depth geometry of the PRF, we used high-resolution seismic imaging methods described by Catchings and others (2014). These methods involve the use of coincident P-wave (compressional wave) and S-wave (shear wave) refraction tomography and reflection data, from which tomographic models of P- and S-wave velocity and P-wave reflection images are developed. In addition, the coincident P-wave velocity (VP) and S-wave velocity (VS) data are used to develop tomographic models of VP/VS ratios and Poisson’s ratio, which are sensitive to shallow-depth faulting and groundwater. In this study, we also compare measurements of Swave velocities determined from surface waves with those determined from refraction tomography. We use the combination of

  14. Optimal Sensor Location Design for Reliable Fault Detection in Presence of False Alarms

    PubMed Central

    Yang, Fan; Xiao, Deyun; Shah, Sirish L.

    2009-01-01

    To improve fault detection reliability, sensor location should be designed according to an optimization criterion with constraints imposed by issues of detectability and identifiability. Reliability requires the minimization of undetectability and false alarm probability due to random factors on sensor readings, which is not only related with sensor readings but also affected by fault propagation. This paper introduces the reliability criteria expression based on the missed/false alarm probability of each sensor and system topology or connectivity derived from the directed graph. The algorithm for the optimization problem is presented as a heuristic procedure. Finally, a boiler system is illustrated using the proposed method. PMID:22291524

  15. A Double-difference Earthquake location algorithm: Method and application to the Northern Hayward Fault, California

    USGS Publications Warehouse

    Waldhauser, F.; Ellsworth, W.L.

    2000-01-01

    We have developed an efficient method to determine high-resolution hypocenter locations over large distances. The location method incorporates ordinary absolute travel-time measurements and/or cross-correlation P-and S-wave differential travel-time measurements. Residuals between observed and theoretical travel-time differences (or double-differences) are minimized for pairs of earthquakes at each station while linking together all observed event-station pairs. A least-squares solution is found by iteratively adjusting the vector difference between hypocentral pairs. The double-difference algorithm minimizes errors due to unmodeled velocity structure without the use of station corrections. Because catalog and cross-correlation data are combined into one system of equations, interevent distances within multiplets are determined to the accuracy of the cross-correlation data, while the relative locations between multiplets and uncorrelated events are simultaneously determined to the accuracy of the absolute travel-time data. Statistical resampling methods are used to estimate data accuracy and location errors. Uncertainties in double-difference locations are improved by more than an order of magnitude compared to catalog locations. The algorithm is tested, and its performance is demonstrated on two clusters of earthquakes located on the northern Hayward fault, California. There it colapses the diffuse catalog locations into sharp images of seismicity and reveals horizontal lineations of hypocenter that define the narrow regions on the fault where stress is released by brittle failure.

  16. Near-surface location, geometry, and velocities of the Santa Monica Fault Zone, Los Angeles, California

    USGS Publications Warehouse

    Catchings, R.D.; Gandhok, G.; Goldman, M.R.; Okaya, D.; Rymer, M.J.; Bawden, G.W.

    2008-01-01

    High-resolution seismic-reflection and seismic-refraction imaging, combined with existing borehole, earthquake, and paleoseismic trenching data, suggest that the Santa Monica fault zone in Los Angeles consists of multiple strands from several kilometers depth to the near surface. We interpret our seismic data as showing two shallow-depth low-angle fault strands and multiple near-vertical (???85??) faults in the upper 100 m. One of the low-angle faults dips northward at about 28?? and approaches the surface at the base of a topographic scarp on the grounds of the Wadsworth VA Hospital (WVAH). The other principal low-angle fault dips northward at about 20?? and projects toward the surface about 200 m south of the topographic scarp, near the northernmost areas of the Los Angeles Basin that experienced strong shaking during the 1994 Northridge earthquake. The 20?? north-dipping low-angle fault is also apparent on a previously published seismic-reflection image by Pratt et al. (1998) and appears to extend northward to at least Wilshire Boulevard, where the fault may be about 450 m below the surface. Slip rates determined at the WVAH site could be significantly underestimated if it is assumed that slip occurs only on a single strand of the Santa Monica fault or if it is assumed that the near-surface faults dip at angles greater than 20-28??. At the WVAH, tomographic velocity modeling shows a significant decrease in velocity across near-surface strands of the Santa Monica fault. P-wave velocities range from about 500 m/sec at the surface to about 4500 m/sec within the upper 50 m on the north side of the fault zone at WVAH, but maximum measured velocities on the south side of the low-angle fault zone at WVAH are about 3500 m/sec. These refraction velocities compare favorably with velocities measured in nearby boreholes by Gibbs et al. (2000). This study illustrates the utility of com- bined seismic-reflection and seismic-refraction methods, which allow more accurate

  17. Evaluation of the Location and Recency of Faulting Near Prospective Surface Facilities in Midway Valley, Nye County, Nevada

    USGS Publications Warehouse

    Swan, F.H.; Wesling, J.R.; Angell, M.M.; Thomas, A.P.; Whitney, J.W.; Gibson, J.D.

    2001-01-01

    Evaluation of surface faulting that may pose a hazard to prospective surface facilities is an important element of the tectonic studies for the potential Yucca Mountain high-level radioactive waste repository in southwestern Nevada. For this purpose, a program of detailed geologic mapping and trenching was done to obtain surface and near-surface geologic data that are essential for determining the location and recency of faults at a prospective surface-facilities site located east of Exile Hill in Midway Valley, near the eastern base of Yucca Mountain. The dominant tectonic features in the Midway Valley area are the north- to northeast-trending, west-dipping normal faults that bound the Midway Valley structural block-the Bow Ridge fault on the west side of Exile Hill and the Paint-brush Canyon fault on the east side of the valley. Trenching of Quaternary sediments has exposed evidence of displacements, which demonstrate that these block-bounding faults repeatedly ruptured the surface during the middle to late Quaternary. Geologic mapping, subsurface borehole and geophysical data, and the results of trenching activities indicate the presence of north- to northeast-trending faults and northwest-trending faults in Tertiary volcanic rocks beneath alluvial and colluvial sediments near the prospective surface-facilities site. North to northeast-trending faults include the Exile Hill fault along the eastern base of Exile Hill and faults to the east beneath the surficial deposits of Midway Valley. These faults have no geomorphic expression, but two north- to northeast-trending zones of fractures exposed in excavated profiles of middle to late Pleistocene deposits at the prospective surface-facilities site appear to be associated with these faults. Northwest-trending faults include the West Portal and East Portal faults, but no disruption of Quaternary deposits by these faults is evident. The western zone of fractures is associated with the Exile Hill fault. The eastern

  18. Empirical Relationships Among Magnitude and Surface Rupture Characteristics of Strike-Slip Faults: Effect of Fault (System) Geometry and Observation Location, Dervided From Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Zielke, O.; Arrowsmith, J.

    2007-12-01

    In order to determine the magnitude of pre-historic earthquakes, surface rupture length, average and maximum surface displacement are utilized, assuming that an earthquake of a specific size will cause surface features of correlated size. The well known Wells and Coppersmith (1994) paper and other studies defined empirical relationships between these and other parameters, based on historic events with independently known magnitude and rupture characteristics. However, these relationships show relatively large standard deviations and they are based only on a small number of events. To improve these first-order empirical relationships, the observation location relative to the rupture extent within the regional tectonic framework should be accounted for. This however cannot be done based on natural seismicity because of the limited size of datasets on large earthquakes. We have developed the numerical model FIMozFric, based on derivations by Okada (1992) to create synthetic seismic records for a given fault or fault system under the influence of either slip- or stress boundary conditions. Our model features A) the introduction of an upper and lower aseismic zone, B) a simple Coulomb friction law, C) bulk parameters simulating fault heterogeneity, and D) a fault interaction algorithm handling the large number of fault patches (typically 5,000-10,000). The joint implementation of these features produces well behaved synthetic seismic catalogs and realistic relationships among magnitude and surface rupture characteristics which are well within the error of the results by Wells and Coppersmith (1994). Furthermore, we use the synthetic seismic records to show that the relationships between magntiude and rupture characteristics are a function of the observation location within the regional tectonic framework. The model presented here can to provide paleoseismologists with a tool to improve magnitude estimates from surface rupture characteristics, by incorporating the

  19. Integrated geophysical investigations in a fault zone located on southwestern part of İzmir city, Western Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Drahor, Mahmut G.; Berge, Meriç A.

    2017-01-01

    Integrated geophysical investigations consisting of joint application of various geophysical techniques have become a major tool of active tectonic investigations. The choice of integrated techniques depends on geological features, tectonic and fault characteristics of the study area, required resolution and penetration depth of used techniques and also financial supports. Therefore, fault geometry and offsets, sediment thickness and properties, features of folded strata and tectonic characteristics of near-surface sections of the subsurface could be thoroughly determined using integrated geophysical approaches. Although Ground Penetrating Radar (GPR), Electrical Resistivity Tomography (ERT) and Seismic Refraction Tomography (SRT) methods are commonly used in active tectonic investigations, other geophysical techniques will also contribute in obtaining of different properties in the complex geological environments of tectonically active sites. In this study, six different geophysical methods used to define faulting locations and characterizations around the study area. These are GPR, ERT, SRT, Very Low Frequency electromagnetic (VLF), magnetics and self-potential (SP). Overall integrated geophysical approaches used in this study gave us commonly important results about the near surface geological properties and faulting characteristics in the investigation area. After integrated interpretations of geophysical surveys, we determined an optimal trench location for paleoseismological studies. The main geological properties associated with faulting process obtained after trenching studies. In addition, geophysical results pointed out some indications concerning the active faulting mechanism in the area investigated. Consequently, the trenching studies indicate that the integrated approach of geophysical techniques applied on the fault problem reveals very useful and interpretative results in description of various properties of faulting zone in the investigation site.

  20. Locating hardware faults in a parallel computer

    DOEpatents

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-04-13

    Locating hardware faults in a parallel computer, including defining within a tree network of the parallel computer two or more sets of non-overlapping test levels of compute nodes of the network that together include all the data communications links of the network, each non-overlapping test level comprising two or more adjacent tiers of the tree; defining test cells within each non-overlapping test level, each test cell comprising a subtree of the tree including a subtree root compute node and all descendant compute nodes of the subtree root compute node within a non-overlapping test level; performing, separately on each set of non-overlapping test levels, an uplink test on all test cells in a set of non-overlapping test levels; and performing, separately from the uplink tests and separately on each set of non-overlapping test levels, a downlink test on all test cells in a set of non-overlapping test levels.

  1. A novel fault location scheme for power distribution system based on injection method and transient line voltage

    NASA Astrophysics Data System (ADS)

    Huang, Yuehua; Li, Xiaomin; Cheng, Jiangzhou; Nie, Deyu; Wang, Zhuoyuan

    2018-02-01

    This paper presents a novel fault location method by injecting travelling wave current. The new methodology is based on Time Difference Of Arrival(TDOA)measurement which is available measurements the injection point and the end node of main radial. In other words, TDOA is the maximum correlation time when the signal reflected wave crest of the injected and fault appear simultaneously. Then distance calculation is equal to the wave velocity multiplied by TDOA. Furthermore, in case of some transformers connected to the end of the feeder, it’s necessary to combine with the transient voltage comparison of amplitude. Finally, in order to verify the effectiveness of this method, several simulations have been undertaken by using MATLAB/SIMULINK software packages. The proposed fault location is useful to short the positioning time in the premise of ensuring the accuracy, besides the error is 5.1% and 13.7%.

  2. Detecting Taiwan's Shanchiao Active Fault Using AMT and Gravity Methods

    NASA Astrophysics Data System (ADS)

    Liu, H.-C.; Yang, C.-H.

    2009-04-01

    Taiwan's Shanchiao normal fault runs in a northeast-southwest direction and is located on the western edge of the Taipei Basin in northern Taiwan. The overburden of the fault is late Quaternary sediment with a thickness of approximately a few tenth of a meter to several hundred meters. No detailed studies of the western side of the Shanchiao fault are available. As Taiwan is located on the Neotectonic Belt in the western Pacific, detecting active faults near the Taipei metropolitan area will provide necessary information for further disaster prevention. It is the responsibility of geologists and geophysicists in Taiwan to perform this task. Examination of the resistivity and density contrasts of subsurface layers permits a mapping of the Shanchiao fault and the deformed Tertiary strata of the Taipei Basin. The audio-frequency magnetotelluric (AMT) method and gravity method were chosen for this study. Significant resistivity and gravity anomalies were observed in the suspected fault zone. The interpretation reveals a good correlation between the features of the Shanchiao fault and resistivity and density distribution at depth. In this observation, AMT and gravity methods provides a viable means for mapping the Shanchiao fault position and studying its features associated with the subsidence of the western side of the Taipei Basin. This study indicates the AMT and gravity methods' considerable potential for accurately mapping an active fault.

  3. Digital release of the Alaska Quaternary fault and fold database

    NASA Astrophysics Data System (ADS)

    Koehler, R. D.; Farrell, R.; Burns, P.; Combellick, R. A.; Weakland, J. R.

    2011-12-01

    The Alaska Division of Geological & Geophysical Surveys (DGGS) has designed a Quaternary fault and fold database for Alaska in conformance with standards defined by the U.S. Geological Survey for the National Quaternary fault and fold database. Alaska is the most seismically active region of the United States, however little information exists on the location, style of deformation, and slip rates of Quaternary faults. Thus, to provide an accurate, user-friendly, reference-based fault inventory to the public, we are producing a digital GIS shapefile of Quaternary fault traces and compiling summary information on each fault. Here, we present relevant information pertaining to the digital GIS shape file and online access and availability of the Alaska database. This database will be useful for engineering geologic studies, geologic, geodetic, and seismic research, and policy planning. The data will also contribute to the fault source database being constructed by the Global Earthquake Model (GEM), Faulted Earth project, which is developing tools to better assess earthquake risk. We derived the initial list of Quaternary active structures from The Neotectonic Map of Alaska (Plafker et al., 1994) and supplemented it with more recent data where available. Due to the limited level of knowledge on Quaternary faults in Alaska, pre-Quaternary fault traces from the Plafker map are shown as a layer in our digital database so users may view a more accurate distribution of mapped faults and to suggest the possibility that some older traces may be active yet un-studied. The database will be updated as new information is developed. We selected each fault by reviewing the literature and georegistered the faults from 1:250,000-scale paper maps contained in 1970's vintage and earlier bedrock maps. However, paper map scales range from 1:20,000 to 1:500,000. Fault parameters in our GIS fault attribute tables include fault name, age, slip rate, slip sense, dip direction, fault line type

  4. Outward-dipping ring-fault structure at rabaul caldera as shown by earthquake locations.

    PubMed

    Mori, J; McKee, C

    1987-01-09

    The locations of a large number of earthquakes recorded at Rabaul caldera in Papua New Guinea from late 1983 to mid-1985 have produced a picture of this active caldera's structural boundary. The earthquake epicenters form an elliptical annulus about 10 kilometers long by 4 kilometers wide, centered in the southern part of the Rabaul volcanic complex. A set of events with well-constrained depth determinations shows a ring-fault structure that extends from the surface to a depth of about 4 kilometers and slopes steeply outward from the center of the caldera. This is the first geophysical data set that clearly outlines the orientation of an active caldera's bounding faults. This orientation, however, conflicts with the configuration of many other calderas and is not in keeping with currently preferred models of caldera formation.

  5. A precise and accurate acupoint location obtained on the face using consistency matrix pointwise fusion method.

    PubMed

    Yanq, Xuming; Ye, Yijun; Xia, Yong; Wei, Xuanzhong; Wang, Zheyu; Ni, Hongmei; Zhu, Ying; Xu, Lingyu

    2015-02-01

    To develop a more precise and accurate method, and identified a procedure to measure whether an acupoint had been correctly located. On the face, we used an acupoint location from different acupuncture experts and obtained the most precise and accurate values of acupoint location based on the consistency information fusion algorithm, through a virtual simulation of the facial orientation coordinate system. Because of inconsistencies in each acupuncture expert's original data, the system error the general weight calculation. First, we corrected each expert of acupoint location system error itself, to obtain a rational quantification for each expert of acupuncture and moxibustion acupoint location consistent support degree, to obtain pointwise variable precision fusion results, to put every expert's acupuncture acupoint location fusion error enhanced to pointwise variable precision. Then, we more effectively used the measured characteristics of different acupuncture expert's acupoint location, to improve the measurement information utilization efficiency and acupuncture acupoint location precision and accuracy. Based on using the consistency matrix pointwise fusion method on the acupuncture experts' acupoint location values, each expert's acupoint location information could be calculated, and the most precise and accurate values of each expert's acupoint location could be obtained.

  6. A Fault Location Algorithm for Two-End Series-Compensated Double-Circuit Transmission Lines Using the Distributed Parameter Line Model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kang, Ning; Gombos, Gergely; Mousavi, Mirrasoul J.

    A new fault location algorithm for two-end series-compensated double-circuit transmission lines utilizing unsynchronized two-terminal current phasors and local voltage phasors is presented in this paper. The distributed parameter line model is adopted to take into account the shunt capacitance of the lines. The mutual coupling between the parallel lines in the zero-sequence network is also considered. The boundary conditions under different fault types are used to derive the fault location formulation. The developed algorithm directly uses the local voltage phasors on the line side of series compensation (SC) and metal oxide varistor (MOV). However, when potential transformers are not installedmore » on the line side of SC and MOVs for the local terminal, these measurements can be calculated from the local terminal bus voltage and currents by estimating the voltages across the SC and MOVs. MATLAB SimPowerSystems is used to generate cases under diverse fault conditions to evaluating accuracy. The simulation results show that the proposed algorithm is qualified for practical implementation.« less

  7. Detection of CMOS bridging faults using minimal stuck-at fault test sets

    NASA Technical Reports Server (NTRS)

    Ijaz, Nabeel; Frenzel, James F.

    1993-01-01

    The performance of minimal stuck-at fault test sets at detecting bridging faults are evaluated. New functional models of circuit primitives are presented which allow accurate representation of bridging faults under switch-level simulation. The effectiveness of the patterns is evaluated using both voltage and current testing.

  8. Fault-related clay authigenesis along the Moab Fault: Implications for calculations of fault rock composition and mechanical and hydrologic fault zone properties

    USGS Publications Warehouse

    Solum, J.G.; Davatzes, N.C.; Lockner, D.A.

    2010-01-01

    The presence of clays in fault rocks influences both the mechanical and hydrologic properties of clay-bearing faults, and therefore it is critical to understand the origin of clays in fault rocks and their distributions is of great importance for defining fundamental properties of faults in the shallow crust. Field mapping shows that layers of clay gouge and shale smear are common along the Moab Fault, from exposures with throws ranging from 10 to ???1000 m. Elemental analyses of four locations along the Moab Fault show that fault rocks are enriched in clays at R191 and Bartlett Wash, but that this clay enrichment occurred at different times and was associated with different fluids. Fault rocks at Corral and Courthouse Canyons show little difference in elemental composition from adjacent protolith, suggesting that formation of fault rocks at those locations is governed by mechanical processes. Friction tests show that these authigenic clays result in fault zone weakening, and potentially influence the style of failure along the fault (seismogenic vs. aseismic) and potentially influence the amount of fluid loss associated with coseismic dilation. Scanning electron microscopy shows that authigenesis promotes that continuity of slip surfaces, thereby enhancing seal capacity. The occurrence of the authigenesis, and its influence on the sealing properties of faults, highlights the importance of determining the processes that control this phenomenon. ?? 2010 Elsevier Ltd.

  9. The 7.9 Denali Fault, Alaska Earthquake of November 3, 2002: Aftershock Locations, Moment Tensors and Focal Mechanisms from the Regional Seismic Network Data

    NASA Astrophysics Data System (ADS)

    Ratchkovski, N. A.; Hansen, R. A.; Kore, K. R.

    2003-04-01

    The largest earthquake ever recorded on the Denali fault system (magnitude 7.9) struck central Alaska on November 3, 2002. It was preceded by a magnitude 6.7 earthquake on October 23. This earlier earthquake and its zone of aftershocks were located ~20 km to the west of the 7.9 quake. Aftershock locations and surface slip observations from the 7.9 quake indicate that the rupture was predominately unilateral in the eastward direction. The geologists mapped a ~300-km-long rupture and measured maximum offsets of 8.8 meters. The 7.9 event ruptured three different faults. The rupture began on the northeast trending Susitna Glacier Thrust fault, a splay fault south of the Denali fault. Then the rupture transferred to the Denali fault and propagated eastward for 220 km. At about 143W the rupture moved onto the adjacent southeast-trending Totschunda fault and propagated for another 55 km. The cumulative length of the 6.7 and 7.9 aftershock zones along the Denali and Totschunda faults is about 380 km. The earthquakes were recorded and processed by the Alaska Earthquake Information Center (AEIC). The AEIC acquires and processes data from the Alaska Seismic Network, consisting of over 350 seismograph stations. Nearly 40 of these sites are equipped with the broad-band sensors, some of which also have strong motion sensors. The rest of the stations are either 1 or 3-component short-period instruments. The data from these stations are collected, processed and archived at the AEIC. The AEIC staff installed a temporary seismic network of 6 instruments following the 6.7 earthquake and an additional 20 stations following the 7.9 earthquake. Prior to the 7.9 Denali Fault event, the AEIC was locating 35 to 50 events per day. After the event, the processing load increased to over 300 events per day during the first week following the event. In this presentation, we will present and interpret the aftershock location patterns, first motion focal mechanism solutions, and regional seismic

  10. Fault zone identification in the eastern part of the Persian Gulf based on combined seismic attributes

    NASA Astrophysics Data System (ADS)

    Mirkamali, M. S.; Keshavarz FK, N.; Bakhtiari, M. R.

    2013-02-01

    Faults, as main pathways for fluids, play a critical role in creating regions of high porosity and permeability, in cutting cap rock and in the migration of hydrocarbons into the reservoir. Therefore, accurate identification of fault zones is very important in maximizing production from petroleum traps. Image processing and modern visualization techniques are provided for better mapping of objects of interest. In this study, the application of fault mapping in the identification of fault zones within the Mishan and Aghajari formations above the Guri base unconformity surface in the eastern part of Persian Gulf is investigated. Seismic single- and multi-trace attribute analyses are employed separately to determine faults in a vertical section, but different kinds of geological objects cannot be identified using individual attributes only. A mapping model is utilized to improve the identification of the faults, giving more accurate results. This method is based on combinations of all individual relevant attributes using a neural network system to create combined attributes, which gives an optimal view of the object of interest. Firstly, a set of relevant attributes were separately calculated on the vertical section. Then, at interpreted positions, some example training locations were manually selected in each fault and non-fault class by an interpreter. A neural network was trained on combinations of the attributes extracted at the example training locations to generate an optimized fault cube. Finally, the results of the fault and nonfault probability cube were estimated, which the neural network applied to the entire data set. The fault probability cube was obtained with higher mapping accuracy and greater contrast, and with fewer disturbances in comparison with individual attributes. The computed results of this study can support better understanding of the data, providing fault zone mapping with reliable results.

  11. Pre-Earthquake Paleoseismic Trenching in 2014 Along a Mapped Trace of the West Napa Fault

    NASA Astrophysics Data System (ADS)

    Rubin, R. S.; Dawson, T. E.; Mareschal, M.

    2014-12-01

    part of fault characterization in order to accurately assess geomorphic features that may, or may not, be formed by tectonic processes. Selection of additional trench locations will be aided by soon-to-be-released post-earthquake LiDAR imagery and existing UAVSAR imagery, with the ultimate goal of preparing an accurate APEFZ in this area.

  12. Ground-Penatrating Radar Investigations Across the Sawmill Branch Fault Near Charleston, South Carolina

    NASA Astrophysics Data System (ADS)

    Dura-Gomez, I.; Addison, A.; Knapp, C. C.; Talwani, P.; Chapman, A.

    2005-12-01

    During the 1886 Charleston earthquake, two parallel tabby walls of Fort Dorchester broke left-laterally, and a strike of ~N25°W was inferred for the causative Sawmill Branch fault. To better define this fault, which does not have any surface expression, we planned to cut trenches across it. However, as Fort Dorchester is a protected archeological site, we were required to locate the fault accurately away from the fort, before permission could be obtained to cut short trenches. The present GPR investigations were planned as a preliminary step to determine locations for trenching. A pulseEKKO 100 GPR was used to collect data along eight profiles (varying in length from 10 m to 30 m) that were run across the projected strike of the fault, and one 50 m long profile that was run parallel to it. The locations of the profiles were obtained using a total station. To capture the signature of the fault, sixteen common-offset (COS) lines were acquired by using different antennas (50, 100 and 200 MHz) and stacking 64 times to increase the signal-to-noise ratio. The location of trees and stumps were recorded. In addition, two common-midpoint (CMP) tests were carried out, and gave an average velocity of about 0.097 m/ns. Processing included the subtraction of the low frequency "wow" on the trace (dewow), automatic gain control (AGC) and the application of bandpass filters. The signals using the 50 MHz, 100 MHz and 200 MHz antennas were found to penetrate up to about 30 meters, 20 meters and 12 meters respectively. Vertically offset reflectors and disruptions of the electrical signal were used to infer the location of the fault(s). Comparisons of the locations of these disruptions on various lines were used to infer the presence of a N30°W fault zone We plan to confirm these locations by cutting shallow trenches.

  13. Practical Methods for Estimating Software Systems Fault Content and Location

    NASA Technical Reports Server (NTRS)

    Nikora, A.; Schneidewind, N.; Munson, J.

    1999-01-01

    Over the past several years, we have developed techniques to discriminate between fault-prone software modules and those that are not, to estimate a software system's residual fault content, to identify those portions of a software system having the highest estimated number of faults, and to estimate the effects of requirements changes on software quality.

  14. Precisely locating the Klamath Falls, Oregon, earthquakes

    USGS Publications Warehouse

    Qamar, A.; Meagher, K.L.

    1993-01-01

    In this article we present preliminary results of a close-in, instrumental study of the Klamath Falls earthquake sequence, carried as a cooperative effort by scientists from the U.S Geological Survey (USGS) and universities in Washington, Orgeon, and California. In addition to obtaining much mroe accurate earthquake locations, this study has improved our understanding of the relationship between seismicity and mapped faults in the region. 

  15. Optimal Design for Placements of Tsunami Observing Systems to Accurately Characterize the Inducing Earthquake

    NASA Astrophysics Data System (ADS)

    Mulia, Iyan E.; Gusman, Aditya Riadi; Satake, Kenji

    2017-12-01

    Recently, there are numerous tsunami observation networks deployed in several major tsunamigenic regions. However, guidance on where to optimally place the measurement devices is limited. This study presents a methodological approach to select strategic observation locations for the purpose of tsunami source characterizations, particularly in terms of the fault slip distribution. Initially, we identify favorable locations and determine the initial number of observations. These locations are selected based on extrema of empirical orthogonal function (EOF) spatial modes. To further improve the accuracy, we apply an optimization algorithm called a mesh adaptive direct search to remove redundant measurement locations from the EOF-generated points. We test the proposed approach using multiple hypothetical tsunami sources around the Nankai Trough, Japan. The results suggest that the optimized observation points can produce more accurate fault slip estimates with considerably less number of observations compared to the existing tsunami observation networks.

  16. On concentrated solute sources in faulted aquifers

    NASA Astrophysics Data System (ADS)

    Robinson, N. I.; Werner, A. D.

    2017-06-01

    Finite aperture faults and fractures within aquifers (collectively called 'faults' hereafter) theoretically enable flowing water to move through them but with refractive displacement, both on entry and exit. When a 2D or 3D point source of solute concentration is located upstream of the fault, the plume emanating from the source relative to one in a fault-free aquifer is affected by the fault, both before it and after it. Previous attempts to analyze this situation using numerical methods faced challenges in overcoming computational constraints that accompany requisite fine mesh resolutions. To address these, an analytical solution of this problem is developed and interrogated using statistical evaluation of solute distributions. The method of solution is based on novel spatial integral representations of the source with axes rotated from the direction of uniform water flow and aligning with fault faces and normals. Numerical exemplification is given to the case of a 2D steady state source, using various parameter combinations. Statistical attributes of solute plumes show the relative impact of parameters, the most important being, fault rotation, aperture and conductivity ratio. New general observations of fault-affected solution plumes are offered, including: (a) the plume's mode (i.e. peak concentration) on the downstream face of the fault is less displaced than the refracted groundwater flowline, but at some distance downstream of the fault, these realign; (b) porosities have no influence in steady state calculations; (c) previous numerical modeling results of barrier faults show significant boundary effects. The current solution adds to available benchmark problems involving fractures, faults and layered aquifers, in which grid resolution effects are often barriers to accurate simulation.

  17. Detection of High-impedance Arcing Faults in Radial Distribution DC Systems

    NASA Technical Reports Server (NTRS)

    Gonzalez, Marcelo C.; Button, Robert M.

    2003-01-01

    High voltage, low current arcing faults in DC power systems have been researched at the NASA Glenn Research Center in order to develop a method for detecting these 'hidden faults', in-situ, before damage to cables and components from localized heating can occur. A simple arc generator was built and high-speed and low-speed monitoring of the voltage and current waveforms, respectively, has shown that these high impedance faults produce a significant increase in high frequency content in the DC bus voltage and low frequency content in the DC system current. Based on these observations, an algorithm was developed using a high-speed data acquisition system that was able to accurately detect high impedance arcing events induced in a single-line system based on the frequency content of the DC bus voltage or the system current. Next, a multi-line, radial distribution system was researched to see if the arc location could be determined through the voltage information when multiple 'detectors' are present in the system. It was shown that a small, passive LC filter was sufficient to reliably isolate the fault to a single line in a multi-line distribution system. Of course, no modification is necessary if only the current information is used to locate the arc. However, data shows that it might be necessary to monitor both the system current and bus voltage to improve the chances of detecting and locating high impedance arcing faults

  18. Deformation associated with continental normal faults

    NASA Astrophysics Data System (ADS)

    Resor, Phillip G.

    Deformation associated with normal fault earthquakes and geologic structures provide insights into the seismic cycle as it unfolds over time scales from seconds to millions of years. Improved understanding of normal faulting will lead to more accurate seismic hazard assessments and prediction of associated structures. High-precision aftershock locations for the 1995 Kozani-Grevena earthquake (Mw 6.5), Greece image a segmented master fault and antithetic faults. This three-dimensional fault geometry is typical of normal fault systems mapped from outcrop or interpreted from reflection seismic data and illustrates the importance of incorporating three-dimensional fault geometry in mechanical models. Subsurface fault slip associated with the Kozani-Grevena and 1999 Hector Mine (Mw 7.1) earthquakes is modeled using a new method for slip inversion on three-dimensional fault surfaces. Incorporation of three-dimensional fault geometry improves the fit to the geodetic data while honoring aftershock distributions and surface ruptures. GPS Surveying of deformed bedding surfaces associated with normal faulting in the western Grand Canyon reveals patterns of deformation that are similar to those observed by interferometric satellite radar interferometry (InSAR) for the Kozani Grevena earthquake with a prominent down-warp in the hanging wall and a lesser up-warp in the footwall. However, deformation associated with the Kozani-Grevena earthquake extends ˜20 km from the fault surface trace, while the folds in the western Grand Canyon only extend 500 m into the footwall and 1500 m into the hanging wall. A comparison of mechanical and kinematic models illustrates advantages of mechanical models in exploring normal faulting processes including incorporation of both deformation and causative forces, and the opportunity to incorporate more complex fault geometry and constitutive properties. Elastic models with antithetic or synthetic faults or joints in association with a master

  19. AIC-based diffraction stacking for local earthquake locations at the Sumatran Fault (Indonesia)

    NASA Astrophysics Data System (ADS)

    Hendriyana, Andri; Bauer, Klaus; Muksin, Umar; Weber, Michael

    2018-05-01

    We present a new workflow for the localization of seismic events which is based on a diffraction stacking approach. In order to address the effects from complex source radiation patterns, we suggest to compute diffraction stacking from a characteristic function (CF) instead of stacking the original waveform data. A new CF, which is called in the following mAIC (modified from Akaike Information Criterion) is proposed. We demonstrate that both P- and S-wave onsets can be detected accurately. To avoid cross-talk between P and S waves due to inaccurate velocity models, we separate the P and S waves from the mAIC function by making use of polarization attributes. Then, the final image function is represented by the largest eigenvalue as a result of the covariance analysis between P- and S-image functions. Results from synthetic experiments show that the proposed diffraction stacking provides reliable results. The workflow of the diffraction stacking method was finally applied to local earthquake data from Sumatra, Indonesia. Recordings from a temporary network of 42 stations deployed for nine months around the Tarutung pull-apart basin were analysed. The seismic event locations resulting from the diffraction stacking method align along a segment of the Sumatran Fault. A more complex distribution of seismicity is imaged within and around the Tarutung basin. Two lineaments striking N-S were found in the centre of the Tarutung basin which support independent results from structural geology.

  20. Formation of an Oceanic Transform Fault During Continental Rifting

    NASA Astrophysics Data System (ADS)

    Illsley-Kemp, F.; Bull, J. M.; Keir, D.; Gerya, T.; Pagli, C.; Gernon, T.; Ayele, A.; Goitom, B.; Hammond, J. O. S.; Kendall, J. M.

    2017-12-01

    We integrate evidence from surface faults, geodetic measurements, local seismicity, and 3D numerical modelling of the subaerial Afar continental rift to show that an oceanic-style transform fault is forming during the final stages of continental breakup. Transform faults are a fundamental tenet of plate tectonics, connecting offset extensional segments of mid-ocean ridges, and are vital in palaeotectonic reconstructions of passive margins. The current consensus is that transform faults initiate after the onset of seafloor spreading. However this inference has been difficult to test given the lack of observations of transform fault formation. We present the first direct observation of transform fault initiation, and shed unprecedented light on their formation mechanisms. We demonstrate that they originate during late-stage continental rifting, earlier in the rifting cycle than previously thought. Our results have important implications for reconstructing the breakup history of the continents. Palaeotectonic reconstructions that use transform fault terminations as an indicator of the continent-ocean boundary may have placed the continent-ocean boundary landward of its true location. This will have led to an overestimation of the age of continental breakup of between 8-18 Myr. Our results therefore have significant implications for studies that rely on accurate dating of continental breakup events.

  1. An Autonomous Distributed Fault-Tolerant Local Positioning System

    NASA Technical Reports Server (NTRS)

    Malekpour, Mahyar R.

    2017-01-01

    We describe a fault-tolerant, GPS-independent (Global Positioning System) distributed autonomous positioning system for static/mobile objects and present solutions for providing highly-accurate geo-location data for the static/mobile objects in dynamic environments. The reliability and accuracy of a positioning system fundamentally depends on two factors; its timeliness in broadcasting signals and the knowledge of its geometry, i.e., locations and distances of the beacons. Existing distributed positioning systems either synchronize to a common external source like GPS or establish their own time synchrony using a scheme similar to a master-slave by designating a particular beacon as the master and other beacons synchronize to it, resulting in a single point of failure. Another drawback of existing positioning systems is their lack of addressing various fault manifestations, in particular, communication link failures, which, as in wireless networks, are increasingly dominating the process failures and are typically transient and mobile, in the sense that they typically affect different messages to/from different processes over time.

  2. Seismicity, faulting, and structure of the Koyna-Warna seismic region, Western India from local earthquake tomography and hypocenter locations

    NASA Astrophysics Data System (ADS)

    Dixit, Madan M.; Kumar, Sanjay; Catchings, R. D.; Suman, K.; Sarkar, Dipankar; Sen, M. K.

    2014-08-01

    Although seismicity near Koyna Reservoir (India) has persisted for ~50 years and includes the largest induced earthquake (M 6.3) reported worldwide, the seismotectonic framework of the area is not well understood. We recorded ~1800 earthquakes from 6 January 2010 to 28 May 2010 and located a subset of 343 of the highest-quality earthquakes using the tomoDD code of Zhang and Thurber (2003) to better understand the framework. We also inverted first arrivals for 3-D Vp, Vs, and Vp/Vs and Poisson's ratio tomography models of the upper 12 km of the crust. Epicenters for the recorded earthquakes are located south of the Koyna River, including a high-density cluster that coincides with a shallow depth (<1.5 km) zone of relatively high Vp and low Vs (also high Vp/Vs and Poisson's ratios) near Warna Reservoir. This anomalous zone, which extends near vertically to at least 8 km depth and laterally northward at least 15 km, is likely a water-saturated zone of faults under high pore pressures. Because many of the earthquakes occur on the periphery of the fault zone, rather than near its center, the observed seismicity-velocity correlations are consistent with the concept that many of the earthquakes nucleate in fractures adjacent to the main fault zone due to high pore pressure. We interpret our velocity images as showing a series of northwest trending faults locally near the central part of Warna Reservoir and a major northward trending fault zone north of Warna Reservoir.

  3. Fault zone structure from topography: signatures of en echelon fault slip at Mustang Ridge on the San Andreas Fault, Monterey County, California

    USGS Publications Warehouse

    DeLong, Stephen B.; Hilley, George E.; Rymer, Michael J.; Prentice, Carol

    2010-01-01

    We used high-resolution topography to quantify the spatial distribution of scarps, linear valleys, topographic sinks, and oversteepened stream channels formed along an extensional step over on the San Andreas Fault (SAF) at Mustang Ridge, California. This location provides detail of both creeping fault landform development and complex fault zone kinematics. Here, the SAF creeps 10–14 mm/yr slower than at locations ∼20 km along the fault in either direction. This spatial change in creep rate is coincident with a series of en echelon oblique-normal faults that strike obliquely to the SAF and may accommodate the missing deformation. This study presents a suite of analyses that are helpful for proper mapping of faults in locations where high-resolution topographic data are available. Furthermore, our analyses indicate that two large subsidiary faults near the center of the step over zone appear to carry significant distributed deformation based on their large apparent vertical offsets, the presence of associated sag ponds and fluvial knickpoints, and the observation that they are rotating a segment of the main SAF. Several subsidiary faults in the southeastern portion of Mustang Ridge are likely less active; they have few associated sag ponds and have older scarp morphologic ages and subdued channel knickpoints. Several faults in the northwestern part of Mustang Ridge, though relatively small, are likely also actively accommodating active fault slip based on their young morphologic ages and the presence of associated sag ponds.

  4. Structural features of the Pernicana Fault (M. Etna, Sicily, Italy) inferred by high precise location of the microseismicity

    NASA Astrophysics Data System (ADS)

    Alparone, S.; Gambino, S.; Mostaccio, A.; Spampinato, S.; Tuvè, T.; Ursino, A.

    2009-04-01

    The north-eastern flank of Mt. Etna is crossed by an important and active tectonic structure, the Pernicana Fault having a mean strike WNW-ESE. It links westward to the active NE Rift and seems to have an important role in controlling instability processes affecting the eastern flank of the volcano. Recent studies suggest that Pernicana Fault is very active through sinistral, oblique-slip movements and is also characterised by frequent shallow seismicity (depth < 2 km bsl) on the uphill western segment and by remarkable creeping on the downhill eastern one. The Pernicana Fault earthquakes, which can reach magnitudes up to 4.2, sometimes with coseismic surface faulting, caused severe damages to tourist resorts and villages along or close this structure. In the last years, a strong increase of seismicity, also characterized by swarms, was recorded by INGV-CT permanent local seismic network close the Pernicana Fault. A three-step procedure was applied to calculate precise hypocentre locations. In a first step, we chose to apply cross-correlation analysis, in order to easily evaluate the similarity of waveforms useful to identify earthquakes families. In a second step, we calculate probabilistic earthquake locations using the software package NONLINLOC, which includes systematic, complete grid search and global, non-linear search methods. Subsequently, we perform relative relocation of correlated event pairs using the double-difference earthquake algorithm and the program HypoDD. The double-difference algorithm minimizes the residuals between observed and calculated travel time difference for pairs of earthquakes at common stations by iteratively adjusting the vector difference between the hypocenters. We show the recognized spatial seismic clusters identifying the most active and hazarding sectors of the structure, their geometry and depth. Finally, in order to clarify the geodynamic framework of the area, we associate these results with calculated focal mechanisms

  5. An improved fault detection classification and location scheme based on wavelet transform and artificial neural network for six phase transmission line using single end data only.

    PubMed

    Koley, Ebha; Verma, Khushaboo; Ghosh, Subhojit

    2015-01-01

    Restrictions on right of way and increasing power demand has boosted development of six phase transmission. It offers a viable alternative for transmitting more power, without major modification in existing structure of three phase double circuit transmission system. Inspite of the advantages, low acceptance of six phase system is attributed to the unavailability of a proper protection scheme. The complexity arising from large number of possible faults in six phase lines makes the protection quite challenging. The proposed work presents a hybrid wavelet transform and modular artificial neural network based fault detector, classifier and locator for six phase lines using single end data only. The standard deviation of the approximate coefficients of voltage and current signals obtained using discrete wavelet transform are applied as input to the modular artificial neural network for fault classification and location. The proposed scheme has been tested for all 120 types of shunt faults with variation in location, fault resistance, fault inception angles. The variation in power system parameters viz. short circuit capacity of the source and its X/R ratio, voltage, frequency and CT saturation has also been investigated. The result confirms the effectiveness and reliability of the proposed protection scheme which makes it ideal for real time implementation.

  6. A 3-D velocity model for earthquake location from combined geological and geophysical data: a case study from the TABOO near fault observatory (Northern Apennines, Italy)

    NASA Astrophysics Data System (ADS)

    Latorre, Diana; Lupattelli, Andrea; Mirabella, Francesco; Trippetta, Fabio; Valoroso, Luisa; Lomax, Anthony; Di Stefano, Raffaele; Collettini, Cristiano; Chiaraluce, Lauro

    2014-05-01

    Accurate hypocenter location at the crustal scale strongly depends on our knowledge of the 3D velocity structure. The integration of geological and geophysical data, when available, should contribute to a reliable seismic velocity model in order to guarantee high quality earthquake locations as well as their consistency with the geological structure. Here we present a 3D, P- and S-wave velocity model of the Upper Tiber valley region (Northern Apennines) retrieved by combining an extremely robust dataset of surface and sub-surface geological data (seismic reflection profiles and boreholes), in situ and laboratory velocity measurements, and earthquake data. The study area is a portion of the Apennine belt undergoing active extension where a set of high-angle normal faults is detached on the Altotiberina low-angle normal fault (ATF). From 2010, this area hosts a scientific infrastructure (the Alto Tiberina Near Fault Observatory, TABOO; http://taboo.rm.ingv.it/), consisting of a dense array of multi-sensor stations, devoted to studying the earthquakes preparatory phase and the deformation processes along the ATF fault system. The proposed 3D velocity model is a layered model in which irregular shaped surfaces limit the boundaries between main lithological units. The model has been constructed by interpolating depth converted seismic horizons interpreted along 40 seismic reflection profiles (down to 4s two way travel times) that have been calibrated with 6 deep boreholes (down to 5 km depth) and constrained by detailed geological maps and structural surveys data. The layers of the model are characterized by similar rock types and seismic velocity properties. The P- and S-waves velocities for each layer have been derived from velocity measurements coming from both boreholes (sonic logs) and laboratory, where measurements have been performed on analogue natural samples increasing confining pressure in order to simulate crustal conditions. In order to test the 3D velocity

  7. Seismicity, faulting, and structure of the Koyna-Warna seismic region, Western India from local earthquake tomography and hypocenter locations

    USGS Publications Warehouse

    Dixit, Madan M.; Kumar, Sanjay; Catchings, Rufus D.; Suman, K.; Sarkar, Dipankar; Sen, M.K.

    2014-01-01

    Although seismicity near Koyna Reservoir (India) has persisted for ~50 years and includes the largest induced earthquake (M 6.3) reported worldwide, the seismotectonic framework of the area is not well understood. We recorded ~1800 earthquakes from 6 January 2010 to 28 May 2010 and located a subset of 343 of the highest-quality earthquakes using the tomoDD code of Zhang and Thurber (2003) to better understand the framework. We also inverted first arrivals for 3-D Vp, Vs, and Vp/Vs and Poisson's ratio tomography models of the upper 12 km of the crust. Epicenters for the recorded earthquakes are located south of the Koyna River, including a high-density cluster that coincides with a shallow depth (<1.5 km) zone of relatively high Vp and low Vs (also high Vp/Vs and Poisson's ratios) near Warna Reservoir. This anomalous zone, which extends near vertically to at least 8 km depth and laterally northward at least 15 km, is likely a water-saturated zone of faults under high pore pressures. Because many of the earthquakes occur on the periphery of the fault zone, rather than near its center, the observed seismicity-velocity correlations are consistent with the concept that many of the earthquakes nucleate in fractures adjacent to the main fault zone due to high pore pressure. We interpret our velocity images as showing a series of northwest trending faults locally near the central part of Warna Reservoir and a major northward trending fault zone north of Warna Reservoir.

  8. Parallel Fault Strands at 9-km Depth Resolved on the Imperial Fault, Southern California

    NASA Astrophysics Data System (ADS)

    Shearer, P. M.

    2001-12-01

    The Imperial Fault is one of the most active faults in California with several M>6 events during the 20th century and geodetic results suggesting that it currently carries almost 80% of the total plate motion between the Pacific and North American plates. We apply waveform cross-correlation to a group of ~1500 microearthquakes along the Imperial Fault and find that about 25% of the events form similar event clusters. Event relocation based on precise differential times among events in these clusters reveals multiple streaks of seismicity up to 5 km in length that are at a nearly constant depth of ~9 km but are spaced about 0.5 km apart in map view. These multiples are unlikely to be a location artifact because they are spaced more widely than the computed location errors and different streaks can be resolved within individual similar event clusters. The streaks are parallel to the mapped surface rupture of the 1979 Mw=6.5 Imperial Valley earthquake. No obvious temporal migration of the event locations is observed. Limited focal mechanism data for the events within the streaks are consistent with right-lateral slip on vertical fault planes. The seismicity not contained in similar event clusters cannot be located as precisely; our locations for these events scatter between 7 and 11 km depth, but it is possible that their true locations could be much more tightly clustered. The observed streaks have some similarities to those previously observed in northern California along the San Andreas and Hayward faults (e.g., Rubin et al., 1999; Waldhauser et al., 1999); however those streaks were imaged within a single fault plane rather than the multiple faults resolved on the Imperial Fault. The apparent constant depth of the Imperial streaks is similar to that seen in Hawaii at much shallower depth by Gillard et al. (1996). Geodetic results (e.g., Lyons et al., 2001) suggest that the Imperial Fault is currently slipping at 45 mm/yr below a locked portion that extends to ~10

  9. Modeling and characterization of partially inserted electrical connector faults

    NASA Astrophysics Data System (ADS)

    Tokgöz, ćaǧatay; Dardona, Sameh; Soldner, Nicholas C.; Wheeler, Kevin R.

    2016-03-01

    Faults within electrical connectors are prominent in avionics systems due to improper installation, corrosion, aging, and strained harnesses. These faults usually start off as undetectable with existing inspection techniques and increase in magnitude during the component lifetime. Detection and modeling of these faults are significantly more challenging than hard failures such as open and short circuits. Hence, enabling the capability to locate and characterize the precursors of these faults is critical for timely preventive maintenance and mitigation well before hard failures occur. In this paper, an electrical connector model based on a two-level nonlinear least squares approach is proposed. The connector is first characterized as a transmission line, broken into key components such as the pin, socket, and connector halves. Then, the fact that the resonance frequencies of the connector shift as insertion depth changes from a fully inserted to a barely touching contact is exploited. The model precisely captures these shifts by varying only two length parameters. It is demonstrated that the model accurately characterizes a partially inserted connector.

  10. Distributed fiber sensing system with wide frequency response and accurate location

    NASA Astrophysics Data System (ADS)

    Shi, Yi; Feng, Hao; Zeng, Zhoumo

    2016-02-01

    A distributed fiber sensing system merging Mach-Zehnder interferometer and phase-sensitive optical time domain reflectometer (Φ-OTDR) is demonstrated for vibration measurement, which requires wide frequency response and accurate location. Two narrow line-width lasers with delicately different wavelengths are used to constitute the interferometer and reflectometer respectively. A narrow band Fiber Bragg Grating is responsible for separating the two wavelengths. In addition, heterodyne detection is applied to maintain the signal to noise rate of the locating signal. Experiment results show that the novel system has a wide frequency from 1 Hz to 50 MHz, limited by the sample frequency of data acquisition card, and a spatial resolution of 20 m, according to 200 ns pulse width, along 2.5 km fiber link.

  11. Fine-scale structure of the San Andreas fault zone and location of the SAFOD target earthquakes

    USGS Publications Warehouse

    Thurber, C.; Roecker, S.; Zhang, H.; Baher, S.; Ellsworth, W.

    2004-01-01

    We present results from the tomographic analysis of seismic data from the Parkfield area using three different inversion codes. The models provide a consistent view of the complex velocity structure in the vicinity of the San Andreas, including a sharp velocity contrast across the fault. We use the inversion results to assess our confidence in the absolute location accuracy of a potential target earthquake. We derive two types of accuracy estimates, one based on a consideration of the location differences from the three inversion methods, and the other based on the absolute location accuracy of "virtual earthquakes." Location differences are on the order of 100-200 m horizontally and up to 500 m vertically. Bounds on the absolute location errors based on the "virtual earthquake" relocations are ??? 50 m horizontally and vertically. The average of our locations places the target event epicenter within about 100 m of the SAF surface trace. Copyright 2004 by the American Geophysical Union.

  12. Seismic images and fault relations of the Santa Monica thrust fault, West Los Angeles, California

    USGS Publications Warehouse

    Catchings, R.D.; Gandhok, G.; Goldman, M.R.; Okaya, D.

    2001-01-01

    a hazard to millions of people, its lateral extent and rupture history are not well known, due largely to limited knowledge of the fault location, geometry, and relationship to other faults. The Santa Monica fault has been obscured at the surface by alluvium and urbanization. For example, Dolan et al. (1995) could find only one 200-m-long stretch of the Santa Monica fault that was not covered by either streets or buildings. Of the 19-km length onshore section of the Santa Monica fault, its apparent location has been delineated largely on the basis of geomorphic features and oil-well drilling. Seismic imaging efforts, in combination with other investigative methods, may be the best approach in locating and understanding the Santa Monica fault in the Los Angeles region. This investigation and another recent seismic imaging investigation (Pratt et al., 1998) were undertaken to resolve the near-surface location, fault geometry, and faulting relations associated with the Santa Monica fault.

  13. Arc burst pattern analysis fault detection system

    NASA Technical Reports Server (NTRS)

    Russell, B. Don (Inventor); Aucoin, B. Michael (Inventor); Benner, Carl L. (Inventor)

    1997-01-01

    A method and apparatus are provided for detecting an arcing fault on a power line carrying a load current. Parameters indicative of power flow and possible fault events on the line, such as voltage and load current, are monitored and analyzed for an arc burst pattern exhibited by arcing faults in a power system. These arcing faults are detected by identifying bursts of each half-cycle of the fundamental current. Bursts occurring at or near a voltage peak indicate arcing on that phase. Once a faulted phase line is identified, a comparison of the current and voltage reveals whether the fault is located in a downstream direction of power flow toward customers, or upstream toward a generation station. If the fault is located downstream, the line is de-energized, and if located upstream, the line may remain energized to prevent unnecessary power outages.

  14. The Sorong Fault Zone, Indonesia: Mapping a Fault Zone Offshore

    NASA Astrophysics Data System (ADS)

    Melia, S.; Hall, R.

    2017-12-01

    The Sorong Fault Zone is a left-lateral strike-slip fault zone in eastern Indonesia, extending westwards from the Bird's Head peninsula of West Papua towards Sulawesi. It is the result of interactions between the Pacific, Caroline, Philippine Sea, and Australian Plates and much of it is offshore. Previous research on the fault zone has been limited by the low resolution of available data offshore, leading to debates over the extent, location, and timing of movements, and the tectonic evolution of eastern Indonesia. Different studies have shown it north of the Sula Islands, truncated south of Halmahera, continuing to Sulawesi, or splaying into a horsetail fan of smaller faults. Recently acquired high resolution multibeam bathymetry of the seafloor (with a resolution of 15-25 meters), and 2D seismic lines, provide the opportunity to trace the fault offshore. The position of different strands can be identified. On land, SRTM topography shows that in the northern Bird's Head the fault zone is characterised by closely spaced E-W trending faults. NW of the Bird's Head offshore there is a fold and thrust belt which terminates some strands. To the west of the Bird's Head offshore the fault zone diverges into multiple strands trending ENE-WSW. Regions of Riedel shearing are evident west of the Bird's Head, indicating sinistral strike-slip motion. Further west, the ENE-WSW trending faults turn to an E-W trend and there are at least three fault zones situated immediately south of Halmahera, north of the Sula Islands, and between the islands of Sanana and Mangole where the fault system terminates in horsetail strands. South of the Sula islands some former normal faults at the continent-ocean boundary with the North Banda Sea are being reactivated as strike-slip faults. The fault zone does not currently reach Sulawesi. The new fault map differs from previous interpretations concerning the location, age and significance of different parts of the Sorong Fault Zone. Kinematic

  15. A robust recognition and accurate locating method for circular coded diagonal target

    NASA Astrophysics Data System (ADS)

    Bao, Yunna; Shang, Yang; Sun, Xiaoliang; Zhou, Jiexin

    2017-10-01

    As a category of special control points which can be automatically identified, artificial coded targets have been widely developed in the field of computer vision, photogrammetry, augmented reality, etc. In this paper, a new circular coded target designed by RockeTech technology Corp. Ltd is analyzed and studied, which is called circular coded diagonal target (CCDT). A novel detection and recognition method with good robustness is proposed in the paper, and implemented on Visual Studio. In this algorithm, firstly, the ellipse features of the center circle are used for rough positioning. Then, according to the characteristics of the center diagonal target, a circular frequency filter is designed to choose the correct center circle and eliminates non-target noise. The precise positioning of the coded target is done by the correlation coefficient fitting extreme value method. Finally, the coded target recognition is achieved by decoding the binary sequence in the outer ring of the extracted target. To test the proposed algorithm, this paper has carried out simulation experiments and real experiments. The results show that the CCDT recognition and accurate locating method proposed in this paper can robustly recognize and accurately locate the targets in complex and noisy background.

  16. Where's the Hayward Fault? A Green Guide to the Fault

    USGS Publications Warehouse

    Stoffer, Philip W.

    2008-01-01

    This report describes self-guided field trips to one of North America?s most dangerous earthquake faults?the Hayward Fault. Locations were chosen because of their easy access using mass transit and/or their significance relating to the natural and cultural history of the East Bay landscape. This field-trip guidebook was compiled to help commemorate the 140th anniversary of an estimated M 7.0 earthquake that occurred on the Hayward Fault at approximately 7:50 AM, October 21st, 1868. Although many reports and on-line resources have been compiled about the science and engineering associated with earthquakes on the Hayward Fault, this report has been prepared to serve as an outdoor guide to the fault for the interested public and for educators. The first chapter is a general overview of the geologic setting of the fault. This is followed by ten chapters of field trips to selected areas along the fault, or in the vicinity, where landscape, geologic, and man-made features that have relevance to understanding the nature of the fault and its earthquake history can be found. A glossary is provided to define and illustrate scientific term used throughout this guide. A ?green? theme helps conserve resources and promotes use of public transportation, where possible. Although access to all locations described in this guide is possible by car, alternative suggestions are provided. To help conserve paper, this guidebook is available on-line only; however, select pages or chapters (field trips) within this guide can be printed separately to take along on an excursion. The discussions in this paper highlight transportation alternatives to visit selected field trip locations. In some cases, combinations, such as a ride on BART and a bus, can be used instead of automobile transportation. For other locales, bicycles can be an alternative means of transportation. Transportation descriptions on selected pages are intended to help guide fieldtrip planners or participants choose trip

  17. Microearthquake sequences along the Irpinia normal fault system in Southern Apennines, Italy

    NASA Astrophysics Data System (ADS)

    Orefice, Antonella; Festa, Gaetano; Alfredo Stabile, Tony; Vassallo, Maurizio; Zollo, Aldo

    2013-04-01

    Microearthquakes reflect a continuous readjustment of tectonic structures, such as faults, under the action of local and regional stress fields. Low magnitude seismicity in the vicinity of active fault zones may reveal insights into the mechanics of the fault systems during the inter-seismic period and shine a light on the role of fluids and other physical parameters in promoting or disfavoring the nucleation of larger size events in the same area. Here we analyzed several earthquake sequences concentrated in very limited regions along the 1980 Irpinia earthquake fault zone (Southern Italy), a complex system characterized by normal stress regime, monitored by the dense, multi-component, high dynamic range seismic network ISNet (Irpinia Seismic Network). On a specific single sequence, the May 2008 Laviano swarm, we performed accurate absolute and relative locations and estimated source parameters and scaling laws that were compared with standard stress-drops computed for the area. Additionally, from EGF deconvolution, we computed a slip model for the mainshock and investigated the space-time evolution of the events in the sequence to reveal possible interactions among earthquakes. Through the massive analysis of cross-correlation based on the master event scanning of the continuous recording, we also reconstructed the catalog of repeated earthquakes and recognized several co-located sequences. For these events, we analyzed the statistical properties, location and source parameters and their space-time evolution with the aim of inferring the processes that control the occurrence and the size of microearthquakes in a swarm.

  18. Fault healing promotes high-frequency earthquakes in laboratory experiments and on natural faults

    USGS Publications Warehouse

    McLaskey, Gregory C.; Thomas, Amanda M.; Glaser, Steven D.; Nadeau, Robert M.

    2012-01-01

    Faults strengthen or heal with time in stationary contact and this healing may be an essential ingredient for the generation of earthquakes. In the laboratory, healing is thought to be the result of thermally activated mechanisms that weld together micrometre-sized asperity contacts on the fault surface, but the relationship between laboratory measures of fault healing and the seismically observable properties of earthquakes is at present not well defined. Here we report on laboratory experiments and seismological observations that show how the spectral properties of earthquakes vary as a function of fault healing time. In the laboratory, we find that increased healing causes a disproportionately large amount of high-frequency seismic radiation to be produced during fault rupture. We observe a similar connection between earthquake spectra and recurrence time for repeating earthquake sequences on natural faults. Healing rates depend on pressure, temperature and mineralogy, so the connection between seismicity and healing may help to explain recent observations of large megathrust earthquakes which indicate that energetic, high-frequency seismic radiation originates from locations that are distinct from the geodetically inferred locations of large-amplitude fault slip

  19. Locating non-volcanic tremor along the San Andreas Fault using a multiple array source imaging technique

    USGS Publications Warehouse

    Ryberg, T.; Haberland, C.H.; Fuis, G.S.; Ellsworth, W.L.; Shelly, D.R.

    2010-01-01

    Non-volcanic tremor (NVT) has been observed at several subduction zones and at the San Andreas Fault (SAF). Tremor locations are commonly derived by cross-correlating envelope-transformed seismic traces in combination with source-scanning techniques. Recently, they have also been located by using relative relocations with master events, that is low-frequency earthquakes that are part of the tremor; locations are derived by conventional traveltime-based methods. Here we present a method to locate the sources of NVT using an imaging approach for multiple array data. The performance of the method is checked with synthetic tests and the relocation of earthquakes. We also applied the method to tremor occurring near Cholame, California. A set of small-aperture arrays (i.e. an array consisting of arrays) installed around Cholame provided the data set for this study. We observed several tremor episodes and located tremor sources in the vicinity of SAF. During individual tremor episodes, we observed a systematic change of source location, indicating rapid migration of the tremor source along SAF. ?? 2010 The Authors Geophysical Journal International ?? 2010 RAS.

  20. Determination of the fault plane and rupture size of the 2013 Santa Cruz earthquake, Bolivia, 5.2 Mw, by relative location of the aftershocks

    NASA Astrophysics Data System (ADS)

    Rivadeneyra-Vera, C.; Assumpção, M.; Minaya, E.; Aliaga, P.; Avila, G.

    2016-11-01

    The Central Andes of southern Bolivia is a highly seismic region with many active faults, that could generate earthquakes up to 8.9 Mw. In 2013, an earthquake of 5.2 Mw occurred in Santa Cruz de la Sierra, in the sub-Andean belt, close to the Mandeyapecua fault, one of the most important reverse faults in Bolivia. Five larger aftershocks were reported by the International Seismological Centre (ISC) and 33 smaller aftershocks were recorded by the San Calixto Observatory (OSC) in the two months after the mainshock. Distances between epicenters of the events were up to 36 km, which is larger than expected for an earthquake of this magnitude. Using data from South American regional stations and the relative location technique with Rayleigh waves, the epicenters of the five larger aftershocks of the Santa Cruz series were determined in relation to the mainshock. This method enabled to achieve epicentral locations with uncertainties smaller than 1 km. Additionally, using data of three Bolivian stations (MOC, SIV and LPAZ) eight smaller aftershocks, recorded by the OSC, were relocated through correlation of P and S waves. The results show a NNW-SSE trend of epicenters and suggest an E dipping plane. The maximum distance between the aftershocks is 14 km, which is not consistent with the expected subsurface rupture length, in accordance with the magnitude of the mainshock. The events are located away from the Mandeyapecua fault and show an opposite dip, demonstrating that these events were generated by another fault in the area, that had not been well studied yet.

  1. Active backstop faults in the Mentawai region of Sumatra, Indonesia, revealed by teleseismic broadband waveform modeling

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Bradley, Kyle Edward; Wei, Shengji; Wu, Wenbo

    2018-02-01

    Two earthquake sequences that affected the Mentawai islands offshore of central Sumatra in 2005 (Mw 6.9) and 2009 (Mw 6.7) have been highlighted as evidence for active backthrusting of the Sumatran accretionary wedge. However, the geometry of the activated fault planes is not well resolved due to large uncertainties in the locations of the mainshocks and aftershocks. We refine the locations and focal mechanisms of medium size events (Mw > 4.5) of these two earthquake sequences through broadband waveform modeling. In addition to modeling the depth-phases for accurate centroid depths, we use teleseismic surface wave cross-correlation to precisely relocate the relative horizontal locations of the earthquakes. The refined catalog shows that the 2005 and 2009 "backthrust" sequences in Mentawai region actually occurred on steeply (∼60 degrees) landward-dipping faults (Masilo Fault Zone) that intersect the Sunda megathrust beneath the deepest part of the forearc basin, contradicting previous studies that inferred slip on a shallowly seaward-dipping backthrust. Static slip inversion on the newly-proposed fault fits the coseismic GPS offsets for the 2009 mainshock equally well as previous studies, but with a slip distribution more consistent with the mainshock centroid depth (∼20 km) constrained from teleseismic waveform inversion. Rupture of such steeply dipping reverse faults within the forearc crust is rare along the Sumatra-Java margin. We interpret these earthquakes as 'unsticking' of the Sumatran accretionary wedge along a backstop fault separating imbricated material from the stronger Sunda lithosphere. Alternatively, the reverse faults may have originated as pre-Miocene normal faults of the extended continental crust of the western Sunda margin. Our waveform modeling approach can be used to further refine global earthquake catalogs in order to clarify the geometries of active faults.

  2. Accurate Vehicle Location System Using RFID, an Internet of Things Approach.

    PubMed

    Prinsloo, Jaco; Malekian, Reza

    2016-06-04

    Modern infrastructure, such as dense urban areas and underground tunnels, can effectively block all GPS signals, which implies that effective position triangulation will not be achieved. The main problem that is addressed in this project is the design and implementation of an accurate vehicle location system using radio-frequency identification (RFID) technology in combination with GPS and the Global system for Mobile communication (GSM) technology, in order to provide a solution to the limitation discussed above. In essence, autonomous vehicle tracking will be facilitated with the use of RFID technology where GPS signals are non-existent. The design of the system and the results are reflected in this paper. An extensive literature study was done on the field known as the Internet of Things, as well as various topics that covered the integration of independent technology in order to address a specific challenge. The proposed system is then designed and implemented. An RFID transponder was successfully designed and a read range of approximately 31 cm was obtained in the low frequency communication range (125 kHz to 134 kHz). The proposed system was designed, implemented, and field tested and it was found that a vehicle could be accurately located and tracked. It is also found that the antenna size of both the RFID reader unit and RFID transponder plays a critical role in the maximum communication range that can be achieved.

  3. Accurate Vehicle Location System Using RFID, an Internet of Things Approach

    PubMed Central

    Prinsloo, Jaco; Malekian, Reza

    2016-01-01

    Modern infrastructure, such as dense urban areas and underground tunnels, can effectively block all GPS signals, which implies that effective position triangulation will not be achieved. The main problem that is addressed in this project is the design and implementation of an accurate vehicle location system using radio-frequency identification (RFID) technology in combination with GPS and the Global system for Mobile communication (GSM) technology, in order to provide a solution to the limitation discussed above. In essence, autonomous vehicle tracking will be facilitated with the use of RFID technology where GPS signals are non-existent. The design of the system and the results are reflected in this paper. An extensive literature study was done on the field known as the Internet of Things, as well as various topics that covered the integration of independent technology in order to address a specific challenge. The proposed system is then designed and implemented. An RFID transponder was successfully designed and a read range of approximately 31 cm was obtained in the low frequency communication range (125 kHz to 134 kHz). The proposed system was designed, implemented, and field tested and it was found that a vehicle could be accurately located and tracked. It is also found that the antenna size of both the RFID reader unit and RFID transponder plays a critical role in the maximum communication range that can be achieved. PMID:27271638

  4. Active Fault Topography and Fault Outcrops in the Central Part of the Nukumi fault, the 1891 Nobi Earthquake Fault System, Central Japan

    NASA Astrophysics Data System (ADS)

    Sasaki, T.; Ueta, K.; Inoue, D.; Aoyagi, Y.; Yanagida, M.; Ichikawa, K.; Goto, N.

    2010-12-01

    It is important to evaluate the magnitude of earthquake caused by multiple active faults, taking into account the simultaneous effects. The simultaneity of adjacent active faults are often decided on the basis of geometric distances except for known these paleoseismic records. We have been studied the step area between the Nukumi fault and the Neodani fault, which appeared as consecutive ruptures in the 1891 Nobi earthquake, since 2009. The purpose of this study is to establish innovation in valuation technique of the simultaneity of adjacent active faults in addition to the paleoseismic record and the geometric distance. Geomorphological, geological and reconnaissance microearthquake surveys are concluded. The present work is intended to clarify the distribution of tectonic geomorphology along the Nukumi fault and the Neodani fault by high-resolution interpretations of airborne LiDAR DEM and aerial photograph, and the field survey of outcrops and location survey. The study area of this work is the southeastern Nukumi fault and the northwestern Neodani fault. We interpret DEM using shaded relief map and stereoscopic bird's-eye view made from 2m mesh DEM data which is obtained by airborne laser scanner of Kokusai Kogyo Co., Ltd. Aerial photographic survey is for confirmation of DEM interpretation using 1/16,000 scale photo. As a result of topographic survey, we found consecutive tectonic topography which is left lateral displacement of ridge and valley lines and reverse scarplets along the Nukumi fault and the Neodani fault . From Ogotani 2km southeastern of Nukumi pass which is located at the southeastern end of surface rupture along the Nukumi fault by previous study to Neooppa 9km southeastern of Nukumi pass, we can interpret left lateral topographies and small uphill-facing fault scarps on the terrace surface by detail DEM investigation. These topographies are unrecognized by aerial photographic survey because of heavy vegetation. We have found several new

  5. High-resolution image of Calaveras fault seismicity

    USGS Publications Warehouse

    Schaff, D.P.; Bokelmann, G.H.R.; Beroza, G.C.; Waldhauser, F.; Ellsworth, W.L.

    2002-01-01

    By measuring relative earthquake arrival times using waveform cross correlation and locating earthquakes using the double difference technique, we are able to reduce hypocentral errors by 1 to 2 orders of magnitude over routine locations for nearly 8000 events along a 35-km section of the Calaveras Fault. This represents ~92% of all seismicity since 1984 and includes the rupture zone of the M 6.2 1984 Morgan Hill, California, earthquake. The relocated seismicity forms highly organized structures that were previously obscured by location errors. There are abundant repeating earthquake sequences as well as linear clusters of earthquakes. Large voids in seismicity appear with dimensions of kilometers that have been aseismic over the 30-year time interval, suggesting that these portions of the fault are either locked or creeping. The area of greatest slip in the Morgan Hill main shock coincides with the most prominent of these voids, suggesting that this part of the fault may be locked between large earthquakes. We find that the Calaveras Fault at depth is extremely thin, with an average upper bound on fault zone width of 75 m. Given the location error, however, this width is not resolvably different from zero. The relocations reveal active secondary faults, which we use to solve for the stress field in the immediate vicinity of the Calaveras Fault. We find that the maximum compressive stress is at a high angle, only 13 from the fault normal, supporting previous interpretations that this fault is weak.

  6. Towards an accurate real-time locator of infrasonic sources

    NASA Astrophysics Data System (ADS)

    Pinsky, V.; Blom, P.; Polozov, A.; Marcillo, O.; Arrowsmith, S.; Hofstetter, A.

    2017-11-01

    Infrasonic signals propagate from an atmospheric source via media with stochastic and fast space-varying conditions. Hence, their travel time, the amplitude at sensor recordings and even manifestation in the so-called "shadow zones" are random. Therefore, the traditional least-squares technique for locating infrasonic sources is often not effective, and the problem for the best solution must be formulated in probabilistic terms. Recently, a series of papers has been published about Bayesian Infrasonic Source Localization (BISL) method based on the computation of the posterior probability density function (PPDF) of the source location, as a convolution of a priori probability distribution function (APDF) of the propagation model parameters with likelihood function (LF) of observations. The present study is devoted to the further development of BISL for higher accuracy and stability of the source location results and decreasing of computational load. We critically analyse previous algorithms and propose several new ones. First of all, we describe the general PPDF formulation and demonstrate that this relatively slow algorithm might be among the most accurate algorithms, provided the adequate APDF and LF are used. Then, we suggest using summation instead of integration in a general PPDF calculation for increased robustness, but this leads us to the 3D space-time optimization problem. Two different forms of APDF approximation are considered and applied for the PPDF calculation in our study. One of them is previously suggested, but not yet properly used is the so-called "celerity-range histograms" (CRHs). Another is the outcome from previous findings of linear mean travel time for the four first infrasonic phases in the overlapping consecutive distance ranges. This stochastic model is extended here to the regional distance of 1000 km, and the APDF introduced is the probabilistic form of the junction between this travel time model and range-dependent probability

  7. A soft computing scheme incorporating ANN and MOV energy in fault detection, classification and distance estimation of EHV transmission line with FSC.

    PubMed

    Khadke, Piyush; Patne, Nita; Singh, Arvind; Shinde, Gulab

    2016-01-01

    In this article, a novel and accurate scheme for fault detection, classification and fault distance estimation for a fixed series compensated transmission line is proposed. The proposed scheme is based on artificial neural network (ANN) and metal oxide varistor (MOV) energy, employing Levenberg-Marquardt training algorithm. The novelty of this scheme is the use of MOV energy signals of fixed series capacitors (FSC) as input to train the ANN. Such approach has never been used in any earlier fault analysis algorithms in the last few decades. Proposed scheme uses only single end measurement energy signals of MOV in all the 3 phases over one cycle duration from the occurrence of a fault. Thereafter, these MOV energy signals are fed as input to ANN for fault distance estimation. Feasibility and reliability of the proposed scheme have been evaluated for all ten types of fault in test power system model at different fault inception angles over numerous fault locations. Real transmission system parameters of 3-phase 400 kV Wardha-Aurangabad transmission line (400 km) with 40 % FSC at Power Grid Wardha Substation, India is considered for this research. Extensive simulation experiments show that the proposed scheme provides quite accurate results which demonstrate complete protection scheme with high accuracy, simplicity and robustness.

  8. The May 29 2008 earthquake aftershock sequence within the South Iceland Seismic Zone: Fault locations and source parameters of aftershocks

    NASA Astrophysics Data System (ADS)

    Brandsdottir, B.; Parsons, M.; White, R. S.; Gudmundsson, O.; Drew, J.

    2010-12-01

    The mid-Atlantic plate boundary breaks up into a series of segments across Iceland. The South Iceland Seismic Zone (SISZ) is a complex transform zone where left-lateral E-W shear between the Reykjanes Peninsula Rift Zone and the Eastern Volcanic Zone is accommodated by bookshelf faulting along N-S lateral strike-slip faults. The SISZ is also a transient feature, migrating sideways in response to the southward propagation of the Eastern Volcanic Zone. Sequences of large earthquakes (M > 6) lasting from days to years and affecting most of the seismic zone have occurred repeatedly in historical time (last 1100 years), separated by intervals of relative quiescence lasting decades to more than a century. On May 29 2008, a Mw 6.1 earthquake struck the western part of the South Iceland Seismic Zone, followed within seconds by a slightly smaller event on a second fault ~5 km further west. Aftershocks, detected by a temporal array of 11 seismometers and three permanent Icelandic Meteorological Office stations were located using an automated Coalescence Microseismic Mapping technique. The epicenters delineate two major and several smaller N-S faults as well as an E-W zone of activity stretching further west into the Reykjanes Peninsula Rift Zone. Fault plane solutions show both right lateral and oblique strike slip mechanisms along the two major N-S faults. The aftershocks deepen from 3-5 km in the north to 8-9 km in the south, suggesting that the main faults dip southwards. The faulting is interpreted to be driven by the local stress due to transform motion between two parallel segments of the divergent plate boundary crossing Iceland.

  9. Refining interseismic fault slip and shallow creep on the Hayward and Calaveras Faults, California, using UAVSAR, satellite InSAR and GPS data

    NASA Astrophysics Data System (ADS)

    Farge, G.; Delbridge, B. G.; Materna, K.; Johnson, C. W.; Chaussard, E.; Jones, C. E.; Burgmann, R.

    2016-12-01

    Understanding the role of the Hayward/Calaveras fault junction in major earthquake ruptures in the East San Francisco Bay Area is a major challenge in trying to assess the regional seismic hazard. We use updated GPS velocities, and surface geodetic measurements from both traditional space-based InSAR and the NASA JPL's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) system to quantify the deep long-term interseismic deformation and shallow temporally variable fault creep. Here, we present a large data set of interseismic deformation over the Hayward/Calaveras fault system, combining far-field deformation from 1992-2011 ERS and Envisat InSAR data, near-field deformation from 2009-2016 UAVSAR data and 1997-2016 regional GPS measurements from the Bay Area Velocity Unification model (BAVU4) in both near-field and far field. We perform a joint inversion of the data to obtain the long-term slip on deep through-going dislocations and the distribution of shallow creep on a 3D model of the Hayward and Calaveras faults. Spatially adaptative weights are given to each data set in order to account for its importance in constraining slip at different depths. The coherence and resolution of the UAVSAR data allow us to accurately resolve the near-field fault deformation, thus providing stronger constraints on the location of active strands of the southern Hayward and Calaveras faults and their shallow interseismic creep distribution.

  10. Evaluation of LiDAR Imagery as a Tool for Mapping the Northern San Andreas Fault in Heavily Forested Areas of Mendocino and Sonoma Counties, California

    NASA Astrophysics Data System (ADS)

    Prentice, C. S.; Koehler, R. D.; Baldwin, J. N.; Harding, D. J.

    2004-12-01

    We are mapping in detail active traces of the San Andreas Fault in Mendocino and Sonoma Counties in northern California, using recently acquired airborne LiDAR (also known as ALSM) data. The LiDAR data set provides a powerful new tool for mapping geomorphic features related to the San Andreas Fault because it can be used to produce high-resolution images of the ground surfaces beneath the forest canopy along the 70-km-long section of the fault zone encompassed by the data. Our effort represents the first use of LiDAR data to map active fault traces in a densely vegetated region along the San Andreas Fault. We are using shaded relief images generated from bare-earth DEMs to conduct detailed mapping of fault-related geomorphic features (e.g. scarps, offset streams, linear valleys, shutter ridges, and sag ponds) between Fort Ross and Point Arena. Initially, we map fault traces digitally, on-screen, based only on the geomorphology interpreted from LiDAR images. We then conduct field reconnaissance using the initial computer-based maps in order to verify and further refine our mapping. We found that field reconnaissance is of utmost importance in producing an accurate and detailed map of fault traces. Many lineaments identified as faults from the on-screen images were determined in the field to be old logging roads or other features unrelated to faulting. Also, in areas where the resolution of LiDAR data is poor, field reconnaissance, coupled with topographic maps and aerial photographs, permits a more accurate location of fault-related geomorphic features. LiDAR images are extremely valuable as a base for field mapping in this heavily forested area, and the use of LiDAR is far superior to traditional mapping techniques relying only on aerial photography and 7.5 minute USGS quadrangle topographic maps. Comparison with earlier mapping of the northern San Andreas fault (Brown and Wolfe, 1972) shows that in some areas the LiDAR data allow a correction of the fault trace

  11. Quantifying Vertical Exhumation in Intracontinental Strike-Slip Faults: the Garlock fault zone, southern California

    NASA Astrophysics Data System (ADS)

    Chinn, L.; Blythe, A. E.; Fendick, A.

    2012-12-01

    New apatite fission-track ages show varying rates of vertical exhumation at the eastern terminus of the Garlock fault zone. The Garlock fault zone is a 260 km long east-northeast striking strike-slip fault with as much as 64 km of sinistral offset. The Garlock fault zone terminates in the east in the Avawatz Mountains, at the intersection with the dextral Southern Death Valley fault zone. Although motion along the Garlock fault west of the Avawatz Mountains is considered purely strike-slip, uplift and exhumation of bedrock in the Avawatz Mountains south of the Garlock fault, as recently as 5 Ma, indicates that transpression plays an important role at this location and is perhaps related to a restricting bend as the fault wraps around and terminates southeastward along the Avawatz Mountains. In this study we complement extant thermochronometric ages from within the Avawatz core with new low temperature fission-track ages from samples collected within the adjacent Garlock and Southern Death Valley fault zones. These thermochronometric data indicate that vertical exhumation rates vary within the fault zone. Two Miocene ages (10.2 (+5.0/-3.4) Ma, 9.0 (+2.2/-1.8) Ma) indicate at least ~3.3 km of vertical exhumation at ~0.35 mm/yr, assuming a 30°C/km geothermal gradient, along a 2 km transect parallel and adjacent to the Mule Spring fault. An older Eocene age (42.9 (+8.7/-7.3) Ma) indicates ~3.3 km of vertical exhumation at ~0.08 mm/yr. These results are consistent with published exhumation rates of 0.35 mm/yr between ~7 and ~4 Ma and 0.13 mm/yr between ~15 and ~9 Ma, as determined by apatite fission-track and U-Th/He thermochronometry in the hanging-wall of the Mule Spring fault. Similar exhumation rates on both sides of the Mule Spring fault support three separate models: 1) Thrusting is no longer active along the Mule Spring fault, 2) Faulting is dominantly strike-slip at the sample locations, or 3) Miocene-present uplift and exhumation is below detection levels

  12. Distributed intrusion monitoring system with fiber link backup and on-line fault diagnosis functions

    NASA Astrophysics Data System (ADS)

    Xu, Jiwei; Wu, Huijuan; Xiao, Shunkun

    2014-12-01

    A novel multi-channel distributed optical fiber intrusion monitoring system with smart fiber link backup and on-line fault diagnosis functions was proposed. A 1× N optical switch was intelligently controlled by a peripheral interface controller (PIC) to expand the fiber link from one channel to several ones to lower the cost of the long or ultra-long distance intrusion monitoring system and also to strengthen the intelligent monitoring link backup function. At the same time, a sliding window auto-correlation method was presented to identify and locate the broken or fault point of the cable. The experimental results showed that the proposed multi-channel system performed well especially whenever any a broken cable was detected. It could locate the broken or fault point by itself accurately and switch to its backup sensing link immediately to ensure the security system to operate stably without a minute idling. And it was successfully applied in a field test for security monitoring of the 220-km-length national borderline in China.

  13. Location of deeply buried, offshore Mesozoic transform fault along the western margin of the Gulf of Mexico inferred from gravity and magnetic data

    NASA Astrophysics Data System (ADS)

    Nguyen, L. C.; Mann, P.; Bird, D. E.

    2013-12-01

    Several workers have proposed that a Jurassic age, 500-km-long, right-lateral transform fault along the western margin of the Gulf of Mexico, possibly extending southward and onshore for another 500 km onto the isthmus area of southern Mexico, was formed as the ocean basin opened. This proposed transform fault plays a critical role in the most widely accepted tectonic model for the Mesozoic opening of the Gulf of Mexico by a ~40 degree, CCW rotation of the Yucatan block about a pole near southern Florida. Previously proposed names for the fault include the Tamaulipas-Chiapas transform fault and the Western Main transform fault for the offshore fault and the Orizaba transform fault for the southern, onland continuation of the fault into southern Mexico. There are few direct geologic or geophysical observations on the location or characteristics of the proposed offshore transform because it is buried beneath an over 10-km-thick sedimentary wedge along the continental margin of eastern Mexico. To better define this offshore fault, we identify a 500-km-long, 40-km-wide gravity anomaly, concentric with, and located about 60-70 km off the eastern coast of Mexico. Two east-west 200/1200-km-long gravity models constructed to cross the anomaly at right angles are parallel to existing multi-channel seismic lines with age-correlated stratigraphy. Both gravity models reveal an abrupt crustal thickness change beneath the gravity anomaly: from 27 km to 12 km over a distance of 65 km in the southern profile, and from 23 km to 16 km over a distance of 30 km in northern profile. The linearity of the anomaly in map view combined with the abrupt change in thickness inferred from gravity modeling is consistent with the tectonic origin of a right-lateral transform fault separating continental rocks of Mexico from Mesozoic seafloor produced by the opening of the Gulf of Mexico. Magnetic profiles were analyzed using a Werner depth-to-magnetic source technique, coincident with the gravity

  14. Applying time-reverse-imaging techniques to locate individual low-frequency earthquakes on the San Andreas fault near Cholame, California

    NASA Astrophysics Data System (ADS)

    Horstmann, T.; Harrington, R. M.; Cochran, E.; Shelly, D. R.

    2013-12-01

    Observations of non-volcanic tremor have become ubiquitous in recent years. In spite of the abundance of observations, locating tremor remains a difficult task because of the lack of distinctive phase arrivals. Here we use time-reverse-imaging techniques that do not require identifying phase arrivals to locate individual low-frequency-earthquakes (LFEs) within tremor episodes on the San Andreas fault near Cholame, California. Time windows of 1.5-second duration containing LFEs are selected from continuously recorded waveforms of the local seismic network filtered between 1-5 Hz. We propagate the time-reversed seismic signal back through the subsurface using a staggered-grid finite-difference code. Assuming all rebroadcasted waveforms result from similar wave fields at the source origin, we search for wave field coherence in time and space to obtain the source location and origin time where the constructive interference is a maximum. We use an interpolated velocity model with a grid spacing of 100 m and a 5 ms time step to calculate the relative curl field energy amplitudes for each rebroadcasted seismogram every 50 ms for each grid point in the model. Finally, we perform a grid search for coherency in the curl field using a sliding time window, and taking the absolute value of the correlation coefficient to account for differences in radiation pattern. The highest median cross-correlation coefficient value over at a given grid point indicates the source location for the rebroadcasted event. Horizontal location errors based on the spatial extent of the highest 10% cross-correlation coefficient are on the order of 4 km, and vertical errors on the order of 3 km. Furthermore, a test of the method using earthquake data shows that the method produces an identical hypocentral location (within errors) as that obtained by standard ray-tracing methods. We also compare the event locations to a LFE catalog that locates the LFEs from stacked waveforms of repeated LFEs

  15. Geophysical and isotopic mapping of preexisting crustal structures that influenced the location and development of the San Jacinto fault zone, southern California

    USGS Publications Warehouse

    Langenheim, V.E.; Jachens, R.C.; Morton, D.M.; Kistler, R.W.; Matti, J.C.

    2004-01-01

    We examine the role of preexisting crustal structure within the Peninsular Ranges batholith on determining the location of the San Jacinto fault zone by analysis of geophysical anomalies and initial strontium ratio data. A 1000-km-long boundary within the Peninsular Ranges batholith, separating relatively mafic, dense, and magnetic rocks of the western Peninsular Ranges batholith from the more felsic, less dense, and weakly magnetic rocks of the eastern Peninsular Ranges batholith, strikes north-northwest toward the San Jacinto fault zone. Modeling of the gravity and magnetic field anomalies caused by this boundary indicates that it extends to depths of at least 20 km. The anomalies do not cross the San Jacinto fault zone, but instead trend northwesterly and coincide with the fault zone. A 75-km-long gradient in initial strontium ratios (Sri) in the eastern Peninsular Ranges batholith coincides with the San Jacinto fault zone. Here rocks east of the fault are characterized by Sri greater than 0.706, indicating a source of largely continental crust, sedimentary materials, or different lithosphere. We argue that the physical property contrast produced by the Peninsular Ranges batholith boundary provided a mechanically favorable path for the San Jacinto fault zone, bypassing the San Gorgonio structural knot as slip was transferred from the San Andreas fault 1.0-1.5 Ma. Two historical M6.7 earthquakes may have nucleated along the Peninsular Ranges batholith discontinuity in San Jacinto Valley, suggesting that Peninsular Ranges batholith crustal structure may continue to affect how strain is accommodated along the San Jacinto fault zone. ?? 2004 Geological Society of America.

  16. A fault diagnosis system for PV power station based on global partitioned gradually approximation method

    NASA Astrophysics Data System (ADS)

    Wang, S.; Zhang, X. N.; Gao, D. D.; Liu, H. X.; Ye, J.; Li, L. R.

    2016-08-01

    As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

  17. Rule-based fault diagnosis of hall sensors and fault-tolerant control of PMSM

    NASA Astrophysics Data System (ADS)

    Song, Ziyou; Li, Jianqiu; Ouyang, Minggao; Gu, Jing; Feng, Xuning; Lu, Dongbin

    2013-07-01

    Hall sensor is widely used for estimating rotor phase of permanent magnet synchronous motor(PMSM). And rotor position is an essential parameter of PMSM control algorithm, hence it is very dangerous if Hall senor faults occur. But there is scarcely any research focusing on fault diagnosis and fault-tolerant control of Hall sensor used in PMSM. From this standpoint, the Hall sensor faults which may occur during the PMSM operating are theoretically analyzed. According to the analysis results, the fault diagnosis algorithm of Hall sensor, which is based on three rules, is proposed to classify the fault phenomena accurately. The rotor phase estimation algorithms, based on one or two Hall sensor(s), are initialized to engender the fault-tolerant control algorithm. The fault diagnosis algorithm can detect 60 Hall fault phenomena in total as well as all detections can be fulfilled in 1/138 rotor rotation period. The fault-tolerant control algorithm can achieve a smooth torque production which means the same control effect as normal control mode (with three Hall sensors). Finally, the PMSM bench test verifies the accuracy and rapidity of fault diagnosis and fault-tolerant control strategies. The fault diagnosis algorithm can detect all Hall sensor faults promptly and fault-tolerant control algorithm allows the PMSM to face failure conditions of one or two Hall sensor(s). In addition, the transitions between health-control and fault-tolerant control conditions are smooth without any additional noise and harshness. Proposed algorithms can deal with the Hall sensor faults of PMSM in real applications, and can be provided to realize the fault diagnosis and fault-tolerant control of PMSM.

  18. Latest Rate, Extent, and Temporal Evolution of Growth Faulting over Greater Houston Region Revealed by Multi- Band InSAR Time-Series Analysis

    NASA Astrophysics Data System (ADS)

    Qu, F.; Lu, Z.; Kim, J. W.

    2017-12-01

    Growth faults are common and continue to evolve throughout the unconsolidated sediments of Greater Houston (GH) region in Texas. Presence of faults can induce localized surface displacements, aggravate localized subsidence, and discontinue the integrity of ground water flow. Property damages due to fault creep have become more evident during the past few years over the GH area, portraying the necessity of further study of these faults. Interferometric synthetic aperture radar (InSAR) has been proven to be effective in mapping creep along and/or across faults. However, extracting a short wavelength, as well as small amplitude of the creep signal (about 10-20 mm/year) from long time span interferograms is extremely difficult, especially in agricultural or vegetated areas. This paper aims to map and monitor the latest rate, extent, and temporal evolution of faulting at a highest spatial density over GH region using an improved Multi-temporal InSAR (MTI) technique. The method, with maximized usable signal and correlation, has the ability to identify and monitor the active faults to provide an accurate and elaborate image of the faults. In this study, two neighboring ALOS tracks and Sentinel-1A datasets are used. Many zones of steep phase gradients and/or discontinuities have been recognized from the long term velocity maps by both ALOS (2007-2011) and Sentinei-1A (2015-2017) imagery. Not only those previously known faults position but also the new fault traces that have not been mapped by other techniques are imaged by our MTI technique. Fault damage and visible cracking of ground were evident at most locations through our field survey. The discovery of new fault activation, or faults moved from earlier locations is a part of the Big Barn Fault and Conroe fault system, trending from southwest to northeast between Hockley and Conroe. The location of area of subsidence over GH is also shrinking and migrating toward the northeast (Montgomery County) after 2000. The

  19. Constraining Basin Depth and Fault Displacement in the Malombe Basin Using Potential Field Methods

    NASA Astrophysics Data System (ADS)

    Beresh, S. C. M.; Elifritz, E. A.; Méndez, K.; Johnson, S.; Mynatt, W. G.; Mayle, M.; Atekwana, E. A.; Laó-Dávila, D. A.; Chindandali, P. R. N.; Chisenga, C.; Gondwe, S.; Mkumbwa, M.; Kalaguluka, D.; Kalindekafe, L.; Salima, J.

    2017-12-01

    The Malombe Basin is part of the Malawi Rift which forms the southern part of the Western Branch of the East African Rift System. At its southern end, the Malawi Rift bifurcates into the Bilila-Mtakataka and Chirobwe-Ntcheu fault systems and the Lake Malombe Rift Basin around the Shire Horst, a competent block under the Nankumba Peninsula. The Malombe Basin is approximately 70km from north to south and 35km at its widest point from east to west, bounded by reversing-polarity border faults. We aim to constrain the depth of the basin to better understand displacement of each border fault. Our work utilizes two east-west gravity profiles across the basin coupled with Source Parameter Imaging (SPI) derived from a high-resolution aeromagnetic survey. The first gravity profile was done across the northern portion of the basin and the second across the southern portion. Gravity and magnetic data will be used to constrain basement depths and the thickness of the sedimentary cover. Additionally, Shuttle Radar Topography Mission (SRTM) data is used to understand the topographic expression of the fault scarps. Estimates for minimum displacement of the border faults on either side of the basin were made by adding the elevation of the scarps to the deepest SPI basement estimates at the basin borders. Our preliminary results using SPI and SRTM data show a minimum displacement of approximately 1.3km for the western border fault; the minimum displacement for the eastern border fault is 740m. However, SPI merely shows the depth to the first significantly magnetic layer in the subsurface, which may or may not be the actual basement layer. Gravimetric readings are based on subsurface density and thus circumvent issues arising from magnetic layers located above the basement; therefore expected results for our work will be to constrain more accurate basin depth by integrating the gravity profiles. Through more accurate basement depth estimates we also gain more accurate displacement

  20. Enriquillo–Plantain Garden fault zone in Jamaica: paleoseismology and seismic hazard

    USGS Publications Warehouse

    Koehler, R.D.; Mann, P.; Prentice, Carol S.; Brown, L.; Benford, B.; Grandison-Wiggins, M.

    2013-01-01

    The countries of Jamaica, Haiti, and the Dominican Republic all straddle the Enriquillo–Plantain Garden fault zone ( EPGFZ), a major left-lateral, strike-slip fault system bounding the Caribbean and North American plates. Past large earthquakes that destroyed the capital cities of Kingston, Jamaica (1692, 1907), and Port-au-Prince, Haiti (1751, 1770), as well as the 2010 Haiti earthquake that killed more than 50,000 people, have heightened awareness of seismic hazards in the northern Caribbean. We present here new geomorphic and paleoseismic information bearing on the location and relative activity of the EPGFZ, which marks the plate boundary in Jamaica. Documentation of a river bank exposure and several trenches indicate that this fault is active and has the potential to cause major destructive earthquakes in Jamaica. The results suggest that the fault has not ruptured the surface in at least 500 yr and possibly as long as 28 ka. The long period of quiescence and subdued geomorphic expression of the EPGFZ indicates that it may only accommodate part of the ∼7–9 mm=yr plate deformation rate measured geodetically and that slip may be partitioned on other undocumented faults. Large uncertainties related to the neotectonic framework of Jamaica remain and more detailed fault characterization studies are necessary to accurately assess seismic hazards.

  1. Robust Fault Diagnosis in Electric Drives Using Machine Learning

    DTIC Science & Technology

    2004-09-08

    detection of fault conditions of the inverter. A machine learning framework is developed to systematically select torque-speed domain operation points...were used to generate various fault condition data for machine learning . The technique is viable for accurate, reliable and fast fault detection in electric drives.

  2. Locating and decoding barcodes in fuzzy images captured by smart phones

    NASA Astrophysics Data System (ADS)

    Deng, Wupeng; Hu, Jiwei; Liu, Quan; Lou, Ping

    2017-07-01

    With the development of barcodes for commercial use, people's requirements for detecting barcodes by smart phone become increasingly pressing. The low quality of barcode image captured by mobile phone always affects the decoding and recognition rates. This paper focuses on locating and decoding EAN-13 barcodes in fuzzy images. We present a more accurate locating algorithm based on segment length and high fault-tolerant rate algorithm for decoding barcodes. Unlike existing approaches, location algorithm is based on the edge segment length of EAN -13 barcodes, while our decoding algorithm allows the appearance of fuzzy region in barcode image. Experimental results are performed on damaged, contaminated and scratched digital images, and provide a quite promising result for EAN -13 barcode location and decoding.

  3. Planetary Gears Feature Extraction and Fault Diagnosis Method Based on VMD and CNN.

    PubMed

    Liu, Chang; Cheng, Gang; Chen, Xihui; Pang, Yusong

    2018-05-11

    Given local weak feature information, a novel feature extraction and fault diagnosis method for planetary gears based on variational mode decomposition (VMD), singular value decomposition (SVD), and convolutional neural network (CNN) is proposed. VMD was used to decompose the original vibration signal to mode components. The mode matrix was partitioned into a number of submatrices and local feature information contained in each submatrix was extracted as a singular value vector using SVD. The singular value vector matrix corresponding to the current fault state was constructed according to the location of each submatrix. Finally, by training a CNN using singular value vector matrices as inputs, planetary gear fault state identification and classification was achieved. The experimental results confirm that the proposed method can successfully extract local weak feature information and accurately identify different faults. The singular value vector matrices of different fault states have a distinct difference in element size and waveform. The VMD-based partition extraction method is better than ensemble empirical mode decomposition (EEMD), resulting in a higher CNN total recognition rate of 100% with fewer training times (14 times). Further analysis demonstrated that the method can also be applied to the degradation recognition of planetary gears. Thus, the proposed method is an effective feature extraction and fault diagnosis technique for planetary gears.

  4. The 2012 Emilia seismic sequence (Northern Italy): Imaging the thrust fault system by accurate aftershock location

    NASA Astrophysics Data System (ADS)

    Govoni, Aladino; Marchetti, Alessandro; De Gori, Pasquale; Di Bona, Massimo; Lucente, Francesco Pio; Improta, Luigi; Chiarabba, Claudio; Nardi, Anna; Margheriti, Lucia; Agostinetti, Nicola Piana; Di Giovambattista, Rita; Latorre, Diana; Anselmi, Mario; Ciaccio, Maria Grazia; Moretti, Milena; Castellano, Corrado; Piccinini, Davide

    2014-05-01

    Starting from late May 2012, the Emilia region (Northern Italy) was severely shaken by an intense seismic sequence, originated from a ML 5.9 earthquake on May 20th, at a hypocentral depth of 6.3 km, with thrust-type focal mechanism. In the following days, the seismic rate remained high, counting 50 ML ≥ 2.0 earthquakes a day, on average. Seismicity spreads along a 30 km east-west elongated area, in the Po river alluvial plain, in the nearby of the cities Ferrara and Modena. Nine days after the first shock, another destructive thrust-type earthquake (ML 5.8) hit the area to the west, causing further damage and fatalities. Aftershocks following this second destructive event extended along the same east-westerly trend for further 20 km to the west, thus illuminating an area of about 50 km in length, on the whole. After the first shock struck, on May 20th, a dense network of temporary seismic stations, in addition to the permanent ones, was deployed in the meizoseismal area, leading to a sensible improvement of the earthquake monitoring capability there. A combined dataset, including three-component seismic waveforms recorded by both permanent and temporary stations, has been analyzed in order to obtain an appropriate 1-D velocity model for earthquake location in the study area. Here we describe the main seismological characteristics of this seismic sequence and, relying on refined earthquakes location, we make inferences on the geometry of the thrust system responsible for the two strongest shocks.

  5. Protection Relaying Scheme Based on Fault Reactance Operation Type

    NASA Astrophysics Data System (ADS)

    Tsuji, Kouichi

    The theories of operation of existing relays are roughly divided into two types: one is the current differential types based on Kirchhoff's first law and the other is impedance types based on second law. We can apply the Kirchhoff's laws to strictly formulate fault phenomena, so the circuit equations are represented non linear simultaneous equations with variables fault point k and fault resistance Rf. This method has next two defect. 1) heavy computational burden for the iterative calculation on N-R method, 2) relay operator can not easily understand principle of numerical matrix operation. The new protection relay principles we proposed this paper focuses on the fact that the reactance component on fault point is almost zero. Two reactance Xf(S), Xf(R) on branch both ends are calculated by operation of solving linear equations. If signs of Xf(S) and Xf(R) are not same, it can be judged that the fault point exist in the branch. This reactance Xf corresponds to difference of branch reactance between actual fault point and imaginaly fault point. And so relay engineer can to understand fault location by concept of “distance". The simulation results using this new method indicates the highly precise estimation of fault locations compared with the inspected fault locations on operating transmission lines.

  6. The buried active faults in southeastern China as revealed by the relocated background seismicity and fault plane solutions

    NASA Astrophysics Data System (ADS)

    Zhu, A.; Wang, P.; Liu, F.

    2017-12-01

    The southeastern China in the mainland corresponds to the south China block, which is characterized by moderate historical seismicity and low stain rate. Most faults are buried under thick Quaternary deposits, so it is difficult to detect and locate them using the routine geological methods. Only a few have been identified to be active in late Quaternary, which leads to relatively high potentially seismic risk to this region due to the unexpected locations of the earthquakes. We performed both hypoDD and tomoDD for the background seismicity from 2000 to 2016 to investigate the buried faults. Some buried active faults are revealed by the relocated seismicity and the velocity structure, no geologically known faults corresponding to them and no surface active evidence ever observed. The geometries of the faults are obtained by analyzing the hypocentral distribution pattern and focal mechanism. The focal mechanism solutions indicate that all the revealed faults are dominated in strike-slip mechanisms, or with some thrust components. While the previous fault investigation and detection results show that most of the Quaternary faults in southeastern China are dominated by normal movement. It suggests that there may exist two fault systems in deep and shallow tectonic regimes. The revealed faults may construct the deep one that act as the seismogenic faults, and the normal faults at shallow cannot generate the destructive earthquakes. The variation in the Curie-point depths agrees well with the structure plane of the revealed active faults, suggesting that the faults may have changed the deep structure.

  7. Fault zone hydrogeology

    NASA Astrophysics Data System (ADS)

    Bense, V. F.; Gleeson, T.; Loveless, S. E.; Bour, O.; Scibek, J.

    2013-12-01

    Deformation along faults in the shallow crust (< 1 km) introduces permeability heterogeneity and anisotropy, which has an important impact on processes such as regional groundwater flow, hydrocarbon migration, and hydrothermal fluid circulation. Fault zones have the capacity to be hydraulic conduits connecting shallow and deep geological environments, but simultaneously the fault cores of many faults often form effective barriers to flow. The direct evaluation of the impact of faults to fluid flow patterns remains a challenge and requires a multidisciplinary research effort of structural geologists and hydrogeologists. However, we find that these disciplines often use different methods with little interaction between them. In this review, we document the current multi-disciplinary understanding of fault zone hydrogeology. We discuss surface- and subsurface observations from diverse rock types from unlithified and lithified clastic sediments through to carbonate, crystalline, and volcanic rocks. For each rock type, we evaluate geological deformation mechanisms, hydrogeologic observations and conceptual models of fault zone hydrogeology. Outcrop observations indicate that fault zones commonly have a permeability structure suggesting they should act as complex conduit-barrier systems in which along-fault flow is encouraged and across-fault flow is impeded. Hydrogeological observations of fault zones reported in the literature show a broad qualitative agreement with outcrop-based conceptual models of fault zone hydrogeology. Nevertheless, the specific impact of a particular fault permeability structure on fault zone hydrogeology can only be assessed when the hydrogeological context of the fault zone is considered and not from outcrop observations alone. To gain a more integrated, comprehensive understanding of fault zone hydrogeology, we foresee numerous synergistic opportunities and challenges for the discipline of structural geology and hydrogeology to co-evolve and

  8. Fault Detection for Automotive Shock Absorber

    NASA Astrophysics Data System (ADS)

    Hernandez-Alcantara, Diana; Morales-Menendez, Ruben; Amezquita-Brooks, Luis

    2015-11-01

    Fault detection for automotive semi-active shock absorbers is a challenge due to the non-linear dynamics and the strong influence of the disturbances such as the road profile. First obstacle for this task, is the modeling of the fault, which has been shown to be of multiplicative nature. Many of the most widespread fault detection schemes consider additive faults. Two model-based fault algorithms for semiactive shock absorber are compared: an observer-based approach and a parameter identification approach. The performance of these schemes is validated and compared using a commercial vehicle model that was experimentally validated. Early results shows that a parameter identification approach is more accurate, whereas an observer-based approach is less sensible to parametric uncertainty.

  9. Weak fault detection and health degradation monitoring using customized standard multiwavelets

    NASA Astrophysics Data System (ADS)

    Yuan, Jing; Wang, Yu; Peng, Yizhen; Wei, Chenjun

    2017-09-01

    Due to the nonobvious symptoms contaminated by a large amount of background noise, it is challenging to beforehand detect and predictively monitor the weak faults for machinery security assurance. Multiwavelets can act as adaptive non-stationary signal processing tools, potentially viable for weak fault diagnosis. However, the signal-based multiwavelets suffer from such problems as the imperfect properties missing the crucial orthogonality, the decomposition distortion impossibly reflecting the relationships between the faults and signatures, the single objective optimization and independence for fault prognostic. Thus, customized standard multiwavelets are proposed for weak fault detection and health degradation monitoring, especially the weak fault signature quantitative identification. First, the flexible standard multiwavelets are designed using the construction method derived from scalar wavelets, seizing the desired properties for accurate detection of weak faults and avoiding the distortion issue for feature quantitative identification. Second, the multi-objective optimization combined three dimensionless indicators of the normalized energy entropy, normalized singular entropy and kurtosis index is introduced to the evaluation criterions, and benefits for selecting the potential best basis functions for weak faults without the influence of the variable working condition. Third, an ensemble health indicator fused by the kurtosis index, impulse index and clearance index of the original signal along with the normalized energy entropy and normalized singular entropy by the customized standard multiwavelets is achieved using Mahalanobis distance to continuously monitor the health condition and track the performance degradation. Finally, three experimental case studies are implemented to demonstrate the feasibility and effectiveness of the proposed method. The results show that the proposed method can quantitatively identify the fault signature of a slight rub on

  10. Comparing Different Fault Identification Algorithms in Distributed Power System

    NASA Astrophysics Data System (ADS)

    Alkaabi, Salim

    A power system is a huge complex system that delivers the electrical power from the generation units to the consumers. As the demand for electrical power increases, distributed power generation was introduced to the power system. Faults may occur in the power system at any time in different locations. These faults cause a huge damage to the system as they might lead to full failure of the power system. Using distributed generation in the power system made it even harder to identify the location of the faults in the system. The main objective of this work is to test the different fault location identification algorithms while tested on a power system with the different amount of power injected using distributed generators. As faults may lead the system to full failure, this is an important area for research. In this thesis different fault location identification algorithms have been tested and compared while the different amount of power is injected from distributed generators. The algorithms were tested on IEEE 34 node test feeder using MATLAB and the results were compared to find when these algorithms might fail and the reliability of these methods.

  11. Seismic and Aseismic Behavior of the Altotiberina Low-angle Normal Fault System (Northern Apennines, Italy) through High-resolution Earthquake Locations and Repeating Events

    NASA Astrophysics Data System (ADS)

    Valoroso, L.; Chiaraluce, L.

    2017-12-01

    Low-angle normal faults (dip < 30°) are geologically widely documented and considered responsible for accommodating the crustal extension within the brittle crust although their mechanical behavior and seismogenic potential is enigmatic. We study the anatomy and slip-behavior of the actively slipping Altotiberina low-angle (ATF) normal fault system using a high-resolution 5-years-long (2010-2014) earthquake catalogue composed of 37k events (ML<3.9 and completeness magnitude MC=0.5 ML), recorded by a dense permanent seismic network of the Altotiberina Near Fault Observatory (TABOO). The seismic activity defines the fault system dominated at depth by the low-angle ATF surface (15-20°) coinciding to the ATF geometry imaged through seismic reflection data. The ATF extends for 50km along-strike and between 4-5 to 16km of depth. Seismicity also images the geometry of a set of higher angle faults (35-50°) located in the ATF hanging-wall (HW). The ATF-related seismicity accounts for 10% of the whole seismicity (3,700 events with ML<2.4), occurring at a remarkably constant rate of 2.2 events/day. This seismicity describes an about 1.5-km-thick fault zone composed by multiple sub-parallel slipping planes. The remaining events are instead organized in multiple mainshocks (MW>3) seismic sequences lasting from weeks to months, activating a contiguous network of 3-5-km-long syn- and antithetic fault segments within the ATF-HW. The space-time evolution of these minor sequences is consistent with subsequence failures promoted by fluid flow. The ATF-seismicity pattern includes 97 clusters of repeating events (RE) made of 299 events with ML<1.9. RE are located around locked patches identified by geodetic modeling, suggesting a mixed-mode (stick-slip and stable-sliding) slip-behavior along the fault plane in accommodating most of the NE-trending tectonic deformation with creeping dominating below 5 km depth. Consistently, the seismic moment released by the ATF-seismicity accounts

  12. Mixed-Mode Slip Behavior of the Altotiberina Low-Angle Normal Fault System (Northern Apennines, Italy) through High-Resolution Earthquake Locations and Repeating Events

    NASA Astrophysics Data System (ADS)

    Valoroso, Luisa; Chiaraluce, Lauro; Di Stefano, Raffaele; Monachesi, Giancarlo

    2017-12-01

    We generated a 4.5-year-long (2010-2014) high-resolution earthquake catalogue, composed of 37,000 events with ML < 3.9 and MC = 0.5 completeness magnitude, to report on the seismic activity of the Altotiberina (ATF) low-angle normal fault system and to shed light on the mechanical behavior and seismic potential of this fault, which is capable of generating a M7 event. Seismicity defines the geometry of the fault system composed of the low-angle (15°-20°) ATF, extending for 50 km along strike and between 4 and 16 km at depth showing an 1.5 km thick fault zone made of multiple subparallel slipping planes, and a complex network of synthetic/antithetic higher-angle segments located in the ATF hanging wall (HW) that can be traced along strike for up to 35 km. Ninety percent of the recorded seismicity occurs along the high-angle HW faults during a series of minor, sometimes long-lasting (months) seismic sequences with multiple MW3+ mainshocks. Remaining earthquakes (ML < 2.4) are released instead along the low-angle ATF at a constant rate of 2.2 events per day. Within the ATF-related seismicity, we found 97 clusters of repeating earthquakes (RE), mostly consisting of doublets occurring during short interevent time (hours). RE are located within the geodetically recognized creeping portions of the ATF, around the main locked asperity. The rate of occurrence of RE seems quite synchronous with the ATF-HW seismic release, suggesting that creeping may guide the strain partitioning in the ATF system. The seismic moment released by the ATF seismicity accounts for 30% of the geodetic one, implying aseismic deformation. The ATF-seismicity pattern is thus consistent with a mixed-mode (seismic and aseismic) slip behavior.

  13. Large earthquakes and creeping faults

    USGS Publications Warehouse

    Harris, Ruth A.

    2017-01-01

    Faults are ubiquitous throughout the Earth's crust. The majority are silent for decades to centuries, until they suddenly rupture and produce earthquakes. With a focus on shallow continental active-tectonic regions, this paper reviews a subset of faults that have a different behavior. These unusual faults slowly creep for long periods of time and produce many small earthquakes. The presence of fault creep and the related microseismicity helps illuminate faults that might not otherwise be located in fine detail, but there is also the question of how creeping faults contribute to seismic hazard. It appears that well-recorded creeping fault earthquakes of up to magnitude 6.6 that have occurred in shallow continental regions produce similar fault-surface rupture areas and similar peak ground shaking as their locked fault counterparts of the same earthquake magnitude. The behavior of much larger earthquakes on shallow creeping continental faults is less well known, because there is a dearth of comprehensive observations. Computational simulations provide an opportunity to fill the gaps in our understanding, particularly of the dynamic processes that occur during large earthquake rupture and arrest.

  14. Application of fault factor method to fault detection and diagnosis for space shuttle main engine

    NASA Astrophysics Data System (ADS)

    Cha, Jihyoung; Ha, Chulsu; Ko, Sangho; Koo, Jaye

    2016-09-01

    This paper deals with an application of the multiple linear regression algorithm to fault detection and diagnosis for the space shuttle main engine (SSME) during a steady state. In order to develop the algorithm, the energy balance equations, which balances the relation among pressure, mass flow rate and power at various locations within the SSME, are obtained. Then using the measurement data of some important parameters of the engine, fault factors which reflects the deviation of each equation from the normal state are estimated. The probable location of each fault and the levels of severity can be obtained from the estimated fault factors. This process is numerically demonstrated for the SSME at 104% Rated Propulsion Level (RPL) by using the simulated measurement data from the mathematical models of the engine. The result of the current study is particularly important considering that the recently developed reusable Liquid Rocket Engines (LREs) have staged-combustion cycles similarly to the SSME.

  15. Influence of fault trend, fault bends, and fault convergence on shallow structure, geomorphology, and hazards, Hosgri strike-slip fault, offshore central California

    NASA Astrophysics Data System (ADS)

    Johnson, S. Y.; Watt, J. T.; Hartwell, S. R.

    2012-12-01

    We mapped a ~94-km-long portion of the right-lateral Hosgri Fault Zone from Point Sal to Piedras Blancas in offshore central California using high-resolution seismic reflection profiles, marine magnetic data, and multibeam bathymetry. The database includes 121 seismic profiles across the fault zone and is perhaps the most comprehensive reported survey of the shallow structure of an active strike-slip fault. These data document the location, length, and near-surface continuity of multiple fault strands, highlight fault-zone heterogeneity, and demonstrate the importance of fault trend, fault bends, and fault convergences in the development of shallow structure and tectonic geomorphology. The Hosgri Fault Zone is continuous through the study area passing through a broad arc in which fault trend changes from about 338° to 328° from south to north. The southern ~40 km of the fault zone in this area is more extensional, resulting in accommodation space that is filled by deltaic sediments of the Santa Maria River. The central ~24 km of the fault zone is characterized by oblique convergence of the Hosgri Fault Zone with the more northwest-trending Los Osos and Shoreline Faults. Convergence between these faults has resulted in the formation of local restraining and releasing fault bends, transpressive uplifts, and transtensional basins of varying size and morphology. We present a hypothesis that links development of a paired fault bend to indenting and bulging of the Hosgri Fault by a strong crustal block translated to the northwest along the Shoreline Fault. Two diverging Hosgri Fault strands bounding a central uplifted block characterize the northern ~30 km of the Hosgri Fault in this area. The eastern Hosgri strand passes through releasing and restraining bends; the releasing bend is the primary control on development of an elongate, asymmetric, "Lazy Z" sedimentary basin. The western strand of the Hosgri Fault Zone passes through a significant restraining bend and

  16. Eigenvector of gravity gradient tensor for estimating fault dips considering fault type

    NASA Astrophysics Data System (ADS)

    Kusumoto, Shigekazu

    2017-12-01

    The dips of boundaries in faults and caldera walls play an important role in understanding their formation mechanisms. The fault dip is a particularly important parameter in numerical simulations for hazard map creation as the fault dip affects estimations of the area of disaster occurrence. In this study, I introduce a technique for estimating the fault dip using the eigenvector of the observed or calculated gravity gradient tensor on a profile and investigating its properties through numerical simulations. From numerical simulations, it was found that the maximum eigenvector of the tensor points to the high-density causative body, and the dip of the maximum eigenvector closely follows the dip of the normal fault. It was also found that the minimum eigenvector of the tensor points to the low-density causative body and that the dip of the minimum eigenvector closely follows the dip of the reverse fault. It was shown that the eigenvector of the gravity gradient tensor for estimating fault dips is determined by fault type. As an application of this technique, I estimated the dip of the Kurehayama Fault located in Toyama, Japan, and obtained a result that corresponded to conventional fault dip estimations by geology and geomorphology. Because the gravity gradient tensor is required for this analysis, I present a technique that estimates the gravity gradient tensor from the gravity anomaly on a profile.

  17. Planetary Gears Feature Extraction and Fault Diagnosis Method Based on VMD and CNN

    PubMed Central

    Cheng, Gang; Chen, Xihui

    2018-01-01

    Given local weak feature information, a novel feature extraction and fault diagnosis method for planetary gears based on variational mode decomposition (VMD), singular value decomposition (SVD), and convolutional neural network (CNN) is proposed. VMD was used to decompose the original vibration signal to mode components. The mode matrix was partitioned into a number of submatrices and local feature information contained in each submatrix was extracted as a singular value vector using SVD. The singular value vector matrix corresponding to the current fault state was constructed according to the location of each submatrix. Finally, by training a CNN using singular value vector matrices as inputs, planetary gear fault state identification and classification was achieved. The experimental results confirm that the proposed method can successfully extract local weak feature information and accurately identify different faults. The singular value vector matrices of different fault states have a distinct difference in element size and waveform. The VMD-based partition extraction method is better than ensemble empirical mode decomposition (EEMD), resulting in a higher CNN total recognition rate of 100% with fewer training times (14 times). Further analysis demonstrated that the method can also be applied to the degradation recognition of planetary gears. Thus, the proposed method is an effective feature extraction and fault diagnosis technique for planetary gears. PMID:29751671

  18. Determining on-fault earthquake magnitude distributions from integer programming

    NASA Astrophysics Data System (ADS)

    Geist, Eric L.; Parsons, Tom

    2018-02-01

    Earthquake magnitude distributions among faults within a fault system are determined from regional seismicity and fault slip rates using binary integer programming. A synthetic earthquake catalog (i.e., list of randomly sampled magnitudes) that spans millennia is first formed, assuming that regional seismicity follows a Gutenberg-Richter relation. Each earthquake in the synthetic catalog can occur on any fault and at any location. The objective is to minimize misfits in the target slip rate for each fault, where slip for each earthquake is scaled from its magnitude. The decision vector consists of binary variables indicating which locations are optimal among all possibilities. Uncertainty estimates in fault slip rates provide explicit upper and lower bounding constraints to the problem. An implicit constraint is that an earthquake can only be located on a fault if it is long enough to contain that earthquake. A general mixed-integer programming solver, consisting of a number of different algorithms, is used to determine the optimal decision vector. A case study is presented for the State of California, where a 4 kyr synthetic earthquake catalog is created and faults with slip ≥3 mm/yr are considered, resulting in >106 variables. The optimal magnitude distributions for each of the faults in the system span a rich diversity of shapes, ranging from characteristic to power-law distributions.

  19. Determining on-fault earthquake magnitude distributions from integer programming

    USGS Publications Warehouse

    Geist, Eric L.; Parsons, Thomas E.

    2018-01-01

    Earthquake magnitude distributions among faults within a fault system are determined from regional seismicity and fault slip rates using binary integer programming. A synthetic earthquake catalog (i.e., list of randomly sampled magnitudes) that spans millennia is first formed, assuming that regional seismicity follows a Gutenberg-Richter relation. Each earthquake in the synthetic catalog can occur on any fault and at any location. The objective is to minimize misfits in the target slip rate for each fault, where slip for each earthquake is scaled from its magnitude. The decision vector consists of binary variables indicating which locations are optimal among all possibilities. Uncertainty estimates in fault slip rates provide explicit upper and lower bounding constraints to the problem. An implicit constraint is that an earthquake can only be located on a fault if it is long enough to contain that earthquake. A general mixed-integer programming solver, consisting of a number of different algorithms, is used to determine the optimal decision vector. A case study is presented for the State of California, where a 4 kyr synthetic earthquake catalog is created and faults with slip ≥3 mm/yr are considered, resulting in >106  variables. The optimal magnitude distributions for each of the faults in the system span a rich diversity of shapes, ranging from characteristic to power-law distributions. 

  20. Assessing active faulting by hydrogeological modeling and superconducting gravimetry: A case study for Hsinchu Fault, Taiwan

    NASA Astrophysics Data System (ADS)

    Lien, Tzuyi; Cheng, Ching-Chung; Hwang, Cheinway; Crossley, David

    2014-09-01

    We develop a new hydrology and gravimetry-based method to assess whether or not a local fault may be active. We take advantage of an existing superconducting gravimeter (SG) station and a comprehensive groundwater network in Hsinchu to apply the method to the Hsinchu Fault (HF) across the Hsinchu Science Park, whose industrial output accounts for 10% of Taiwan's gross domestic product. The HF is suspected to pose seismic hazards to the park, but its existence and structure are not clear. The a priori geometry of the HF is translated into boundary conditions imposed in the hydrodynamic model. By varying the fault's location, depth, and including a secondary wrench fault, we construct five hydrodynamic models to estimate groundwater variations, which are evaluated by comparing groundwater levels and SG observations. The results reveal that the HF contains a low hydraulic conductivity core and significantly impacts groundwater flows in the aquifers. Imposing the fault boundary conditions leads to about 63-77% reduction in the differences between modeled and observed values (both water level and gravity). The test with fault depth shows that the HF's most recent slip occurred in the beginning of Holocene, supplying a necessary (but not sufficient) condition that the HF is currently active. A portable SG can act as a virtual borehole well for model assessment at critical locations of a suspected active fault.

  1. Network Connectivity for Permanent, Transient, Independent, and Correlated Faults

    NASA Technical Reports Server (NTRS)

    White, Allan L.; Sicher, Courtney; henry, Courtney

    2012-01-01

    This paper develops a method for the quantitative analysis of network connectivity in the presence of both permanent and transient faults. Even though transient noise is considered a common occurrence in networks, a survey of the literature reveals an emphasis on permanent faults. Transient faults introduce a time element into the analysis of network reliability. With permanent faults it is sufficient to consider the faults that have accumulated by the end of the operating period. With transient faults the arrival and recovery time must be included. The number and location of faults in the system is a dynamic variable. Transient faults also introduce system recovery into the analysis. The goal is the quantitative assessment of network connectivity in the presence of both permanent and transient faults. The approach is to construct a global model that includes all classes of faults: permanent, transient, independent, and correlated. A theorem is derived about this model that give distributions for (1) the number of fault occurrences, (2) the type of fault occurrence, (3) the time of the fault occurrences, and (4) the location of the fault occurrence. These results are applied to compare and contrast the connectivity of different network architectures in the presence of permanent, transient, independent, and correlated faults. The examples below use a Monte Carlo simulation, but the theorem mentioned above could be used to guide fault-injections in a laboratory.

  2. Stafford fault system: 120 million year fault movement history of northern Virginia

    USGS Publications Warehouse

    Powars, David S.; Catchings, Rufus D.; Horton, J. Wright; Schindler, J. Stephen; Pavich, Milan J.

    2015-01-01

    The Stafford fault system, located in the mid-Atlantic coastal plain of the eastern United States, provides the most complete record of fault movement during the past ~120 m.y. across the Virginia, Washington, District of Columbia (D.C.), and Maryland region, including displacement of Pleistocene terrace gravels. The Stafford fault system is close to and aligned with the Piedmont Spotsylvania and Long Branch fault zones. The dominant southwest-northeast trend of strong shaking from the 23 August 2011, moment magnitude Mw 5.8 Mineral, Virginia, earthquake is consistent with the connectivity of these faults, as seismic energy appears to have traveled along the documented and proposed extensions of the Stafford fault system into the Washington, D.C., area. Some other faults documented in the nearby coastal plain are clearly rooted in crystalline basement faults, especially along terrane boundaries. These coastal plain faults are commonly assumed to have undergone relatively uniform movement through time, with average slip rates from 0.3 to 1.5 m/m.y. However, there were higher rates during the Paleocene–early Eocene and the Pliocene (4.4–27.4 m/m.y), suggesting that slip occurred primarily during large earthquakes. Further investigation of the Stafford fault system is needed to understand potential earthquake hazards for the Virginia, Maryland, and Washington, D.C., area. The combined Stafford fault system and aligned Piedmont faults are ~180 km long, so if the combined fault system ruptured in a single event, it would result in a significantly larger magnitude earthquake than the Mineral earthquake. Many structures most strongly affected during the Mineral earthquake are along or near the Stafford fault system and its proposed northeastward extension.

  3. Accurate Damage Location in Complex Composite Structures and Industrial Environments using Acoustic Emission

    NASA Astrophysics Data System (ADS)

    Eaton, M.; Pearson, M.; Lee, W.; Pullin, R.

    2015-07-01

    The ability to accurately locate damage in any given structure is a highly desirable attribute for an effective structural health monitoring system and could help to reduce operating costs and improve safety. This becomes a far greater challenge in complex geometries and materials, such as modern composite airframes. The poor translation of promising laboratory based SHM demonstrators to industrial environments forms a barrier to commercial up take of technology. The acoustic emission (AE) technique is a passive NDT method that detects elastic stress waves released by the growth of damage. It offers very sensitive damage detection, using a sparse array of sensors to detect and globally locate damage within a structure. However its application to complex structures commonly yields poor accuracy due to anisotropic wave propagation and the interruption of wave propagation by structural features such as holes and thickness changes. This work adopts an empirical mapping technique for AE location, known as Delta T Mapping, which uses experimental training data to account for such structural complexities. The technique is applied to a complex geometry composite aerospace structure undergoing certification testing. The component consists of a carbon fibre composite tube with varying wall thickness and multiple holes, that was loaded under bending. The damage location was validated using X-ray CT scanning and the Delta T Mapping technique was shown to improve location accuracy when compared with commercial algorithms. The onset and progression of damage were monitored throughout the test and used to inform future design iterations.

  4. Controls of repeating earthquakes' location from a- and b- values imaging

    NASA Astrophysics Data System (ADS)

    Chen, K. H.; Kawamura, M.

    2017-12-01

    The locations where creeping and locked fault areas abut have commonly found to be delineated by the foci of small repeating earthquakes (REs). REs not only represent the finer structure of high creep-rate location, they also function as fault slip-rate indicators. Knowledge of the expected location of REs therefore, is crucial for fault deformation monitoring and assessment of earthquake potential. However, a precise description of factors determining REs locations is lacking. To explore where earthquakes tend to recur, we statistically investigated repeating earthquake catalogs and background seismicity from different regions including six fault segments in California and Taiwan. We show that the location of repeating earthquakes can be mapped using the spatial distribution of the seismic a- and b-values obtained from the background seismicity. Molchan's error diagram statistically confirmed that repeating earthquakes occur within areas with high a-values (2.8-3.8) and high b-values (0.9-1.1) on both strike-slip and thrust fault segments. However, no significant association held true for fault segments with more complicated geometry or for wider areas with a complex fault network. The productivity of small earthquakes responsible for high a- and b-values may thus be the most important factor controlling the location of repeating earthquakes. We hypothesize that, given that the deformation conditions within a fault zone are suitable for a planar fault plane, the location of repeating earthquakes can be best described by a-value 3 and b-value 1. This feature of a- and b-values may be useful for foresee the location of REs for measuring creep rate at depth. Further investigation of REs-rich areas may allow testing of this hypothesis.

  5. Computing Fault Displacements from Surface Deformations

    NASA Technical Reports Server (NTRS)

    Lyzenga, Gregory; Parker, Jay; Donnellan, Andrea; Panero, Wendy

    2006-01-01

    Simplex is a computer program that calculates locations and displacements of subterranean faults from data on Earth-surface deformations. The calculation involves inversion of a forward model (given a point source representing a fault, a forward model calculates the surface deformations) for displacements, and strains caused by a fault located in isotropic, elastic half-space. The inversion involves the use of nonlinear, multiparameter estimation techniques. The input surface-deformation data can be in multiple formats, with absolute or differential positioning. The input data can be derived from multiple sources, including interferometric synthetic-aperture radar, the Global Positioning System, and strain meters. Parameters can be constrained or free. Estimates can be calculated for single or multiple faults. Estimates of parameters are accompanied by reports of their covariances and uncertainties. Simplex has been tested extensively against forward models and against other means of inverting geodetic data and seismic observations. This work

  6. Earthquake disaster mitigation of Lembang Fault West Java with electromagnetic method

    NASA Astrophysics Data System (ADS)

    Widodo

    2015-04-01

    The Lembang fault is located around eight kilometers from Bandung City, West Java, Indonesia. The existence of this fault runs through densely populated settlement and tourism area. It is an active fault structure with increasing seismic activity where the 28 August 2011 earthquake occurred. The seismic response at the site is strongly influenced by local geological conditions. The ambient noise measurements from the western part of this fault give strong implication for a complex 3-D tectonic setting. Hence, near surface Electromagnetic (EM) measurements are carried out to understand the location of the local active fault of the research area. Hence, near surface EM measurements are carried out to understand the location of the local active fault and the top of the basement structure of the research area. The Transientelectromagnetic (TEM) measurements are carried out along three profiles, which include 35 TEM soundings. The results indicate that TEM data give detailed conductivity distribution of fault structure in the study area.

  7. Earthquake disaster mitigation of Lembang Fault West Java with electromagnetic method

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Widodo, E-mail: widodo@gf.itb.ac.id

    The Lembang fault is located around eight kilometers from Bandung City, West Java, Indonesia. The existence of this fault runs through densely populated settlement and tourism area. It is an active fault structure with increasing seismic activity where the 28 August 2011 earthquake occurred. The seismic response at the site is strongly influenced by local geological conditions. The ambient noise measurements from the western part of this fault give strong implication for a complex 3-D tectonic setting. Hence, near surface Electromagnetic (EM) measurements are carried out to understand the location of the local active fault of the research area. Hence,more » near surface EM measurements are carried out to understand the location of the local active fault and the top of the basement structure of the research area. The Transientelectromagnetic (TEM) measurements are carried out along three profiles, which include 35 TEM soundings. The results indicate that TEM data give detailed conductivity distribution of fault structure in the study area.« less

  8. Stacking-fault nucleation on Ir(111).

    PubMed

    Busse, Carsten; Polop, Celia; Müller, Michael; Albe, Karsten; Linke, Udo; Michely, Thomas

    2003-08-01

    Variable temperature scanning tunneling microscopy experiments reveal that in Ir(111) homoepitaxy islands nucleate and grow both in the regular fcc stacking and in the faulted hcp stacking. Analysis of this effect in dependence on deposition temperature leads to an atomistic model of stacking-fault formation: The large, metastable stacking-fault islands grow by sufficiently fast addition of adatoms to small mobile adatom clusters which occupy in thermal equilibrium the hcp sites with a significant probability. Using parameters derived independently by field ion microscopy, the model accurately describes the results for Ir(111) and is expected to be valid also for other surfaces.

  9. Efficient fault diagnosis of helicopter gearboxes

    NASA Technical Reports Server (NTRS)

    Chin, H.; Danai, K.; Lewicki, D. G.

    1993-01-01

    Application of a diagnostic system to a helicopter gearbox is presented. The diagnostic system is a nonparametric pattern classifier that uses a multi-valued influence matrix (MVIM) as its diagnostic model and benefits from a fast learning algorithm that enables it to estimate its diagnostic model from a small number of measurement-fault data. To test this diagnostic system, vibration measurements were collected from a helicopter gearbox test stand during accelerated fatigue tests and at various fault instances. The diagnostic results indicate that the MVIM system can accurately detect and diagnose various gearbox faults so long as they are included in training.

  10. Accurate characterisation of hole size and location by projected fringe profilometry

    NASA Astrophysics Data System (ADS)

    Wu, Yuxiang; Dantanarayana, Harshana G.; Yue, Huimin; Huntley, Jonathan M.

    2018-06-01

    The ability to accurately estimate the location and geometry of holes is often required in the field of quality control and automated assembly. Projected fringe profilometry is a potentially attractive technique on account of being non-contacting, of lower cost, and orders of magnitude faster than the traditional coordinate measuring machine. However, we demonstrate in this paper that fringe projection is susceptible to significant (hundreds of µm) measurement artefacts in the neighbourhood of hole edges, which give rise to errors of a similar magnitude in the estimated hole geometry. A mechanism for the phenomenon is identified based on the finite size of the imaging system’s point spread function and the resulting bias produced near to sample discontinuities in geometry and reflectivity. A mathematical model is proposed, from which a post-processing compensation algorithm is developed to suppress such errors around the holes. The algorithm includes a robust and accurate sub-pixel edge detection method based on a Fourier descriptor of the hole contour. The proposed algorithm was found to reduce significantly the measurement artefacts near the hole edges. As a result, the errors in estimated hole radius were reduced by up to one order of magnitude, to a few tens of µm for hole radii in the range 2–15 mm, compared to those from the uncompensated measurements.

  11. Frictional heterogeneities on carbonate-bearing normal faults: Insights from the Monte Maggio Fault, Italy

    NASA Astrophysics Data System (ADS)

    Carpenter, B. M.; Scuderi, M. M.; Collettini, C.; Marone, C.

    2014-12-01

    Observations of heterogeneous and complex fault slip are often attributed to the complexity of fault structure and/or spatial heterogeneity of fault frictional behavior. Such complex slip patterns have been observed for earthquakes on normal faults throughout central Italy, where many of the Mw 6 to 7 earthquakes in the Apennines nucleate at depths where the lithology is dominated by carbonate rocks. To explore the relationship between fault structure and heterogeneous frictional properties, we studied the exhumed Monte Maggio Fault, located in the northern Apennines. We collected intact specimens of the fault zone, including the principal slip surface and hanging wall cataclasite, and performed experiments at a normal stress of 10 MPa under saturated conditions. Experiments designed to reactivate slip between the cemented principal slip surface and cataclasite show a 3 MPa stress drop as the fault surface fails, then velocity-neutral frictional behavior and significant frictional healing. Overall, our results suggest that (1) earthquakes may readily nucleate in areas of the fault where the slip surface separates massive limestone and are likely to propagate in areas where fault gouge is in contact with the slip surface; (2) postseismic slip is more likely to occur in areas of the fault where gouge is present; and (3) high rates of frictional healing and low creep relaxation observed between solid fault surfaces could lead to significant aftershocks in areas of low stress drop.

  12. New evidence on the accurate displacement along the Arava/Araba segment of the Dead Sea Transform

    NASA Astrophysics Data System (ADS)

    Beyth, M.; Sagy, A.; Hajazi, H.; Alkhraisha, S.; Mushkin, A.; Ginat, H.

    2018-06-01

    The sinistral displacement along the Dead Sea Transform (DST), the plate boundary between the African and the Arabian plates, south of the Dead Sea basin, was previously attributed to two main fault zones: the Arava/Araba or Dead Sea fault and the Feinan or Al Quwayra fault zone. This was based on similarities of features on either side of the Araba Valley. In particular, the Timna and the Feinan copper mines, located north of the Themed and Dana faults, and the onlap of the Cambrian formations southward onto the Amram rhyolite and Ahyamir volcanics. To these we add a more accurate offset indicator in the form of an offset Early Cambrian (532 Ma) dolerite dyke previously mapped in Mount Amram (Israel) on the African plate and recently discovered across the Araba Valley in Jabal Sumr al Tayyiba (southwest Jordan) on the Arabian plate. This dolerite dyke is 20 m thick, strikes N50°E and is the only dyke intruding the Jabal Sumr al Tayyiba pink rhyolite flows of the Ahyamir Volcanics. Geochemical and geochronological correlations between the Jabal Sumr al Tayyiba dolerite dyke and the Mount Amram dolerite dyke demonstrate 85 km of sinistral offset across the Arava/Araba fault. Our results also suggest approximately 109 km of combined sinistral displacement across the Arava/Araba and Feinan faults based on petrological correlations between the Timna and Jabal Hanna igneous complexes on the African and Arabian plates, respectively. This constrains the total sinistral displacement of the Feinan fault and its accessory faults to be 24 km.

  13. New evidence on the accurate displacement along the Arava/Araba segment of the Dead Sea Transform

    NASA Astrophysics Data System (ADS)

    Beyth, M.; Sagy, A.; Hajazi, H.; Alkhraisha, S.; Mushkin, A.; Ginat, H.

    2017-11-01

    The sinistral displacement along the Dead Sea Transform (DST), the plate boundary between the African and the Arabian plates, south of the Dead Sea basin, was previously attributed to two main fault zones: the Arava/Araba or Dead Sea fault and the Feinan or Al Quwayra fault zone. This was based on similarities of features on either side of the Araba Valley. In particular, the Timna and the Feinan copper mines, located north of the Themed and Dana faults, and the onlap of the Cambrian formations southward onto the Amram rhyolite and Ahyamir volcanics. To these we add a more accurate offset indicator in the form of an offset Early Cambrian (532 Ma) dolerite dyke previously mapped in Mount Amram (Israel) on the African plate and recently discovered across the Araba Valley in Jabal Sumr al Tayyiba (southwest Jordan) on the Arabian plate. This dolerite dyke is 20 m thick, strikes N50°E and is the only dyke intruding the Jabal Sumr al Tayyiba pink rhyolite flows of the Ahyamir Volcanics. Geochemical and geochronological correlations between the Jabal Sumr al Tayyiba dolerite dyke and the Mount Amram dolerite dyke demonstrate 85 km of sinistral offset across the Arava/Araba fault. Our results also suggest approximately 109 km of combined sinistral displacement across the Arava/Araba and Feinan faults based on petrological correlations between the Timna and Jabal Hanna igneous complexes on the African and Arabian plates, respectively. This constrains the total sinistral displacement of the Feinan fault and its accessory faults to be 24 km.

  14. Lower Learning Difficulty and Fluoroscopy Reduction of Transforaminal Percutaneous Endoscopic Lumbar Discectomy with an Accurate Preoperative Location Method.

    PubMed

    Fan, Guoxin; Gu, Xin; Liu, Yifan; Wu, Xinbo; Zhang, Hailong; Gu, Guangfei; Guan, Xiaofei; He, Shisheng

    2016-01-01

    Transforaminal percutaneous endoscopic lumbar discectomy (tPELD) poses great challenges for junior surgeons. Beginners often require repeated attempts using fluoroscopy causing more punctures, which may significantly undermine their confidence and increase the radiation exposure to medical staff and patients. Moreover, the impact of an accurate location on the learning curve of tPELD has not been defined. The study aimed to investigate the impact of an accurate preoperative location method on learning difficulty and fluoroscopy time of tPELD. Retrospective evaluation. Patients receiving tPELD by one surgeon with a novel accurate preoperative location method were regarded as Group A, and those receiving tPELD by another surgeon with a conventional fluoroscopy method were regarded as Group B. From January 2012 to August 2014, we retrospectively reviewed the first 80 tPELD cases conducted by 2 junior surgeons. The operation time, fluoroscopy times, preoperative location time, and puncture-channel time were thoroughly analyzed. The operation time of the first 20 patients were 99.75 ± 10.38 minutes in Group A and 115.7 ± 16.46 minutes in Group B, while the operation time of all 80 patients was 88.36 ± 11.56 minutes in Group A and 98.26 ± 14.90 minutes in Group B. Significant differences were detected in operation time between the 2 groups, both for the first 20 patients and total 80 patients (P < 0.05). The fluoroscopy times were 26.78 ± 4.17 in Group A and 33.98 ± 2.69 in Group B (P < 0.001). The preoperative location time was 3.43 ± 0.61 minutes in Group A and 5.59 ± 1.46 minutes in Group B (P < 0.001). The puncture-channel time was 27.20 ± 4.49 minutes in Group A and 34.64 ± 8.35 minutes in Group B (P < 0.001). There was a moderate correlation between preoperative location time and puncture-channel time (r = 0.408, P < 0.001), and a moderate correlation between preoperative location time and fluoroscopy times (r = 0.441, P < 0.001). Mild correlations were

  15. Fault-Sensitivity and Wear-Out Analysis of VLSI Systems.

    DTIC Science & Technology

    1995-06-01

    DESCRIPTION MIXED-MODE HIERARCIAIFAULT DESCRIPTION FAULT SIMULATION TYPE OF FAULT TRANSIENT/STUCK-AT LOCATION/TIME * _AUTOMATIC FAULT INJECTION TRACE...4219-4224, December 1985. [15] J. Sosnowski, "Evaluation of transient hazards in microprocessor controll - ers," Digest, FTCS-16, The Sixteenth

  16. Using marine magnetic survey data to identify a gold ore-controlling fault: a case study in Sanshandao fault, eastern China

    NASA Astrophysics Data System (ADS)

    Yan, Jiayong; Wang, Zhihui; Wang, Jinhui; Song, Jianhua

    2018-06-01

    The Jiaodong Peninsula has the greatest concentration of gold ore in China and is characterized by altered tectonite-type gold ore deposits. This type of gold deposit is mainly formed in fracture zones and is strictly controlled by faults. Three major ore-controlling faults occur in the Jiaodong Peninsula—the Jiaojia, Zhaoping and Sanshandao faults; the former two are located on land and the latter is located near Sanshandao and its adjacent offshore area. The discovery of the world’s largest marine gold deposit in northeastern Sanshandao indicates that the shallow offshore area has great potential for gold prospecting. However, as two ends of the Sanshandao fault extend to the Bohai Sea, conventional geological survey methods cannot determine the distribution of the fault and this is constraining the discovery of new gold deposits. To explore the southwestward extension of the Sanshandao fault, we performed a 1:25 000 scale marine magnetic survey in this region and obtained high-quality magnetic survey data covering 170 km2. Multi-scale edge detection and three-dimensional inversion of magnetic anomalies identify the characteristics of the southwestward extension of the Sanshandao fault and the three-dimensional distribution of the main lithologies, providing significant evidence for the deployment of marine gold deposit prospecting in the southern segment of the Sanshandao fault. Moreover, three other faults were identified in the study area and faults F2 and F4 are inferred as ore-controlling faults: there may exist other altered tectonite-type gold ore deposits along these two faults.

  17. Misbheaving Faults: The Expanding Role of Geodetic Imaging in Unraveling Unexpected Fault Slip Behavior

    NASA Astrophysics Data System (ADS)

    Barnhart, W. D.; Briggs, R.

    2015-12-01

    of geologic and geodetic slip rates. As such, detailed studies such as this will play a continuing vital role in the accurate assessment of short- and long-term fault slip kinematics.

  18. Fault detection and isolation for complex system

    NASA Astrophysics Data System (ADS)

    Jing, Chan Shi; Bayuaji, Luhur; Samad, R.; Mustafa, M.; Abdullah, N. R. H.; Zain, Z. M.; Pebrianti, Dwi

    2017-07-01

    Fault Detection and Isolation (FDI) is a method to monitor, identify, and pinpoint the type and location of system fault in a complex multiple input multiple output (MIMO) non-linear system. A two wheel robot is used as a complex system in this study. The aim of the research is to construct and design a Fault Detection and Isolation algorithm. The proposed method for the fault identification is using hybrid technique that combines Kalman filter and Artificial Neural Network (ANN). The Kalman filter is able to recognize the data from the sensors of the system and indicate the fault of the system in the sensor reading. Error prediction is based on the fault magnitude and the time occurrence of fault. Additionally, Artificial Neural Network (ANN) is another algorithm used to determine the type of fault and isolate the fault in the system.

  19. Characterization of Fault Size in Bearings

    DTIC Science & Technology

    2014-12-23

    suggests to use the ratio between the horizontal and the vertical RMS as an indicator of the fault location is not applicable for small faults. Since...Vibration Monitoring of rolling element bearing by the high- frequency resonance technique - a review, Tribology international, Vol. 17, pp 3-10. M

  20. Planetary Gearbox Fault Detection Using Vibration Separation Techniques

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; LaBerge, Kelsen E.; Ehinger, Ryan T.; Fetty, Jason

    2011-01-01

    Studies were performed to demonstrate the capability to detect planetary gear and bearing faults in helicopter main-rotor transmissions. The work supported the Operations Support and Sustainment (OSST) program with the U.S. Army Aviation Applied Technology Directorate (AATD) and Bell Helicopter Textron. Vibration data from the OH-58C planetary system were collected on a healthy transmission as well as with various seeded-fault components. Planetary fault detection algorithms were used with the collected data to evaluate fault detection effectiveness. Planet gear tooth cracks and spalls were detectable using the vibration separation techniques. Sun gear tooth cracks were not discernibly detectable from the vibration separation process. Sun gear tooth spall defects were detectable. Ring gear tooth cracks were only clearly detectable by accelerometers located near the crack location or directly across from the crack. Enveloping provided an effective method for planet bearing inner- and outer-race spalling fault detection.

  1. Features and dimensions of the Hayward Fault Zone in the Strawberry and Blackberry Creek Area, Berkeley, California

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Williams, P.L.

    1995-03-01

    This report presents an examination of the geometry of the Hayward fault adjacent to the Lawrence Berkeley Laboratory and University of California campuses in central Berkeley. The fault crosses inside the eastern border of the UC campus. Most subtle geomorphic (landform) expressions of the fault have been removed by development and by the natural processes of landsliding and erosion. Some clear expressions of the fault remain however, and these are key to mapping the main trace through the campus area. In addition, original geomorphic evidence of the fault`s location was recovered from large scale mapping of the site dating frommore » 1873 to 1897. Before construction obscured and removed natural landforms, the fault was expressed by a linear, northwest-tending zone of fault-related geomorphic features. There existed well-defined and subtle stream offsets and beheaded channels, fault scarps, and a prominent ``shutter ridge``. To improve our confidence in fault locations interpreted from landforms, we referred to clear fault exposures revealed in trenching, revealed during the construction of the Foothill Housing Complex, and revealed along the length of the Lawson Adit mining tunnel. Also utilized were the locations of offset cultural features. At several locations across the study area, distress features in buildings and streets have been used to precisely locate the fault. Recent published mapping of the fault (Lienkaemper, 1992) was principally used for reference to evidence of the fault`s location to the northwest and southeast of Lawrence Berkeley Laboratory.« less

  2. The SCEC 3D Community Fault Model (CFM-v5): An updated and expanded fault set of oblique crustal deformation and complex fault interaction for southern California

    NASA Astrophysics Data System (ADS)

    Nicholson, C.; Plesch, A.; Sorlien, C. C.; Shaw, J. H.; Hauksson, E.

    2014-12-01

    Southern California represents an ideal natural laboratory to investigate oblique deformation in 3D owing to its comprehensive datasets, complex tectonic history, evolving components of oblique slip, and continued crustal rotations about horizontal and vertical axes. As the SCEC Community Fault Model (CFM) aims to accurately reflect this 3D deformation, we present the results of an extensive update to the model by using primarily detailed fault trace, seismic reflection, relocated hypocenter and focal mechanism nodal plane data to generate improved, more realistic digital 3D fault surfaces. The results document a wide variety of oblique strain accommodation, including various aspects of strain partitioning and fault-related folding, sets of both high-angle and low-angle faults that mutually interact, significant non-planar, multi-stranded faults with variable dip along strike and with depth, and active mid-crustal detachments. In places, closely-spaced fault strands or fault systems can remain surprisingly subparallel to seismogenic depths, while in other areas, major strike-slip to oblique-slip faults can merge, such as the S-dipping Arroyo Parida-Mission Ridge and Santa Ynez faults with the N-dipping North Channel-Pitas Point-Red Mountain fault system, or diverge with depth. Examples of the latter include the steep-to-west-dipping Laguna Salada-Indiviso faults with the steep-to-east-dipping Sierra Cucapah faults, and the steep southern San Andreas fault with the adjacent NE-dipping Mecca Hills-Hidden Springs fault system. In addition, overprinting by steep predominantly strike-slip faulting can segment which parts of intersecting inherited low-angle faults are reactivated, or result in mutual cross-cutting relationships. The updated CFM 3D fault surfaces thus help characterize a more complex pattern of fault interactions at depth between various fault sets and linked fault systems, and a more complex fault geometry than typically inferred or expected from

  3. Fault-tolerant arithmetic via time-shared TMR

    NASA Astrophysics Data System (ADS)

    Swartzlander, Earl E.

    1999-11-01

    Fault tolerance is increasingly important as society has come to depend on computers for more and more aspects of daily life. The current concern about the Y2K problems indicates just how much we depend on accurate computers. This paper describes work on time- shared TMR, a technique which is used to provide arithmetic operations that produce correct results in spite of circuit faults.

  4. ISHM-oriented adaptive fault diagnostics for avionics based on a distributed intelligent agent system

    NASA Astrophysics Data System (ADS)

    Xu, Jiuping; Zhong, Zhengqiang; Xu, Lei

    2015-10-01

    In this paper, an integrated system health management-oriented adaptive fault diagnostics and model for avionics is proposed. With avionics becoming increasingly complicated, precise and comprehensive avionics fault diagnostics has become an extremely complicated task. For the proposed fault diagnostic system, specific approaches, such as the artificial immune system, the intelligent agents system and the Dempster-Shafer evidence theory, are used to conduct deep fault avionics diagnostics. Through this proposed fault diagnostic system, efficient and accurate diagnostics can be achieved. A numerical example is conducted to apply the proposed hybrid diagnostics to a set of radar transmitters on an avionics system and to illustrate that the proposed system and model have the ability to achieve efficient and accurate fault diagnostics. By analyzing the diagnostic system's feasibility and pragmatics, the advantages of this system are demonstrated.

  5. A new protocol to accurately determine microtubule lattice seam location

    DOE PAGES

    Zhang, Rui; Nogales, Eva

    2015-09-28

    Microtubules (MTs) are cylindrical polymers of αβ-tubulin that display pseudo-helical symmetry due to the presence of a lattice seam of heterologous lateral contacts. The structural similarity between α- and β-tubulin makes it difficult to computationally distinguish them in the noisy cryo-EM images, unless a marker protein for the tubulin dimer, such as kinesin motor domain, is present. We have developed a new data processing protocol that can accurately determine αβ-tubulin register and seam location for MT segments. Our strategy can handle difficult situations, where the marker protein is relatively small or the decoration of marker protein is sparse. Using thismore » new seam-search protocol, combined with movie processing for data from a direct electron detection camera, we were able to determine the cryo-EM structures of MT at 3.5. Å resolution in different functional states. The successful distinction of α- and β-tubulin allowed us to visualize the nucleotide state at the E-site and the configuration of lateral contacts at the seam.« less

  6. Surface fault rupture during the Mw 7.8 Kaikoura earthquake, New Zealand, with specific comment on the Kekerengu Fault - one of the country's fastest slipping onland active faults

    NASA Astrophysics Data System (ADS)

    Van Dissen, Russ; Little, Tim

    2017-04-01

    The Mw 7.8 Kaikoura earthquake of 14 November, 2016 (NZDT) was a complex event. It involved ground-surface (or seafloor) fault rupture on at least a dozen onland or offshore faults, and subsurface rupture on a handful of additional faults. Most of the surface ruptures involved previously known (or suspected) active faults, as well as surface rupture on at least two hitherto unrecognised active faults. The southwest to northeast extent of surface fault rupture, as generalised by two straight-line segments, is approximately 180 km, though this is a minimum for the collective length of surface rupture due to multiple overlapping faults with various orientations. Surface rupture displacements on specific faults involved in the Kaikoura Earthquake span approximately two orders of magnitude. For example, maximum surface displacement on the Heaver's Creek Fault is cm- to dm-scale in size; whereas, maximum surface displacement on the nearby Kekerengu Fault is approximately 10-12 m (predominantly in a dextral sense). The Kekerengu Fault has a Late Pleistocene slip-rate rate of 20-26 mm/yr, and is possibly the second fastest slipping onland fault in New Zealand, behind the Alpine Fault. Located in the northeastern South Island of New Zealand, the Kekerengu Fault - along with the Hope Fault to the southwest and the Needles Fault offshore to the northeast - comprise the fastest slipping elements of the Pacific-Australian plate boundary in this part of the country. In January 2016 (about ten months prior to the Kaikoura earthquake) three paleo-earthquake investigation trenches were excavated across pronounced traces of the Kekerengu Fault at two locations. These were the first such trenches dug and evaluated across the fault. All three trenches displayed abundant evidence of past surface fault ruptures (three surface ruptures in the last approximately 1,200 years, four now including the 2016 rupture). An interesting aspect of the 2016 rupture is that two of the trenches

  7. A multiple fault rupture model of the November 13 2016, M 7.8 Kaikoura earthquake, New Zealand

    NASA Astrophysics Data System (ADS)

    Benites, R. A.; Francois-Holden, C.; Langridge, R. M.; Kaneko, Y.; Fry, B.; Kaiser, A. E.; Caldwell, T. G.

    2017-12-01

    The rupture-history of the November 13 2016 MW7.8 Kaikoura earthquake recorded by near- and intermediate-field strong-motion seismometers and 2 high-rate GPS stations reveals a complex cascade of multiple crustal fault rupture. In spite of such complexity, we show that the rupture history of each fault is well approximated by simple kinematic model with uniform slip and rupture velocity. Using 9 faults embedded in a crustal layer 19 km thick, each with a prescribed slip vector and rupture velocity, this model accurately reproduces the displacement waveforms recorded at the near-field strong-motion and GPS stations. This model includes the `Papatea Fault' with a mixed thrust and strike-slip mechanism based on in-situ geological observations with up to 8 m of uplift observed. Although the kinematic model fits the ground-motion at the nearest strong station, it doesn not reproduce the one sided nature of the static deformation field observed geodetically. This suggests a dislocation based approach does not completely capture the mechanical response of the Papatea Fault. The fault system as a whole extends for approximately 150 km along the eastern side of the Marlborough fault system in the South Island of New Zealand. The total duration of the rupture was 74 seconds. The timing and location of each fault's rupture suggests fault interaction and triggering resulting in a northward cascade crustal ruptures. Our model does not require rupture of the underlying subduction interface to explain the data.

  8. Aftershocks of the 2014 South Napa, California, Earthquake: Complex faulting on secondary faults

    USGS Publications Warehouse

    Hardebeck, Jeanne L.; Shelly, David R.

    2016-01-01

    We investigate the aftershock sequence of the 2014 MW6.0 South Napa, California, earthquake. Low-magnitude aftershocks missing from the network catalog are detected by applying a matched-filter approach to continuous seismic data, with the catalog earthquakes serving as the waveform templates. We measure precise differential arrival times between events, which we use for double-difference event relocation in a 3D seismic velocity model. Most aftershocks are deeper than the mainshock slip, and most occur west of the mapped surface rupture. While the mainshock coseismic and postseismic slip appears to have occurred on the near-vertical, strike-slip West Napa fault, many of the aftershocks occur in a complex zone of secondary faulting. Earthquake locations in the main aftershock zone, near the mainshock hypocenter, delineate multiple dipping secondary faults. Composite focal mechanisms indicate strike-slip and oblique-reverse faulting on the secondary features. The secondary faults were moved towards failure by Coulomb stress changes from the mainshock slip. Clusters of aftershocks north and south of the main aftershock zone exhibit vertical strike-slip faulting more consistent with the West Napa Fault. The northern aftershocks correspond to the area of largest mainshock coseismic slip, while the main aftershock zone is adjacent to the fault area that has primarily slipped postseismically. Unlike most creeping faults, the zone of postseismic slip does not appear to contain embedded stick-slip patches that would have produced on-fault aftershocks. The lack of stick-slip patches along this portion of the fault may contribute to the low productivity of the South Napa aftershock sequence.

  9. Location of long-period events below Kilauea Volcano using seismic amplitudes and accurate relative relocation

    USGS Publications Warehouse

    Battaglia, J.; Got, J.-L.; Okubo, P.

    2003-01-01

    We present methods for improving the location of long-period (LP) events, deep and shallow, recorded below Kilauea Volcano by the permanent seismic network. LP events might be of particular interest to understanding eruptive processes as their source mechanism is assumed to directly involve fluid transport. However, it is usually difficult or impossible to locate their source using traditional arrival time methods because of emergent wave arrivals. At Kilauea, similar LP waveform signatures suggest the existence of LP multiplets. The waveform similarity suggests spatially close sources, while catalog solutions using arrival time estimates are widely scattered beneath Kilauea's summit caldera. In order to improve estimates of absolute LP location, we use the distribution of seismic amplitudes corrected for station site effects. The decay of the amplitude as a function of hypocentral distance is used for inferring LP location. In a second stage, we use the similarity of the events to calculate their relative positions. The analysis of the entire LP seismicity recorded between January 1997 and December 1999 suggests that a very large part of the LP event population, both deep and shallow, is generated by a small number of compact sources. Deep events are systematically composed of a weak high-frequency onset followed by a low-frequency wave train. Aligning the low-frequency wave trains does not lead to aligning the onsets indicating the two parts of the signal are dissociated. This observation favors an interpretation in terms of triggering and resonance of a magmatic conduit. Instead of defining fault planes, the precise relocation of similar LP events, based on the alignment of the high-energy low-frequency wave trains, defines limited size volumes. Copyright 2003 by the American Geophysical Union.

  10. Earthquake Nucleation and Fault Slip: Possible Experiments on a Natural Fault

    NASA Astrophysics Data System (ADS)

    Germanovich, L. N.; Murdoch, L. C.; Garagash, D.; Reches, Z.; Martel, S. J.; Johnston, M. J.; Ebenhack, J.; Gwaba, D.

    2011-12-01

    High-resolution deformation and seismic observations are usually made only near the Earths' surface, kilometers away from where earthquake nucleate on active faults and are limited by inverse-cube-distance attenuation and ground noise. We have developed an experimental approach that aims at reactivating faults in-situ using thermal techniques and fluid injection, which modify in-situ stresses and the fault strength until the fault slips. Mines where in-situ stresses are sufficient to drive faulting present an opportunity to conduct such experiments. The former Homestake gold mine in South Dakota is a good example. During our recent field work in the Homestake mine, we found a large fault that intersects multiple mine levels. The size and distinct structure of this fault make it a promising target for in-situ reactivation, which would likely to be localized on a crack-like patch. Slow patch propagation, moderated by the injection rate and the rate of change of the background stresses, may become unstable, leading to the nucleation of a dynamic earthquake rupture. Our analyses for the Homestake fault conditions indicate that this transition occurs for a patch size ~1 m. This represents a fundamental limitation for laboratory experiments and necessitates larger-scale field tests ~10-100 m. The opportunity to observe earthquake nucleation on the Homestake Fault is feasible because slip could be initiated at a pre-defined location and time with instrumentation placed as close as a few meters from the nucleation site. Designing the experiment requires a detailed assessment of the state-of-stress in the vicinity of the fault. This is being conducted by simulating changes in pore pressure and effective stresses accompanying dewatering of the mine, and by evaluating in-situ stress measurements in light of a regional stress field modified by local perturbations caused by the mine workings.

  11. Fault parameter constraints using relocated earthquakes: A validation of first-motion focal-mechanism data

    USGS Publications Warehouse

    Kilb, Debi; Hardebeck, J.L.

    2006-01-01

    We estimate the strike and dip of three California fault segments (Calaveras, Sargent, and a portion of the San Andreas near San Jaun Bautistia) based on principle component analysis of accurately located microearthquakes. We compare these fault orientations with two different first-motion focal mechanism catalogs: the Northern California Earthquake Data Center (NCEDC) catalog, calculated using the FPFIT algorithm (Reasenberg and Oppenheimer, 1985), and a catalog created using the HASH algorithm that tests mechanism stability relative to seismic velocity model variations and earthquake location (Hardebeck and Shearer, 2002). We assume any disagreement (misfit >30° in strike, dip, or rake) indicates inaccurate focal mechanisms in the catalogs. With this assumption, we can quantify the parameters that identify the most optimally constrained focal mechanisms. For the NCEDC/FPFIT catalogs, we find that the best quantitative discriminator of quality focal mechanisms is the station distribution ratio (STDR) parameter, an indicator of how the stations are distributed about the focal sphere. Requiring STDR > 0.65 increases the acceptable mechanisms from 34%–37% to 63%–68%. This suggests stations should be uniformly distributed surrounding, rather than aligning, known fault traces. For the HASH catalogs, the fault plane uncertainty (FPU) parameter is the best discriminator, increasing the percent of acceptable mechanisms from 63%–78% to 81%–83% when FPU ≤ 35°. The overall higher percentage of acceptable mechanisms and the usefulness of the formal uncertainty in identifying quality mechanisms validate the HASH approach of testing for mechanism stability.

  12. Applications of Fault Detection in Vibrating Structures

    NASA Technical Reports Server (NTRS)

    Eure, Kenneth W.; Hogge, Edward; Quach, Cuong C.; Vazquez, Sixto L.; Russell, Andrew; Hill, Boyd L.

    2012-01-01

    Structural fault detection and identification remains an area of active research. Solutions to fault detection and identification may be based on subtle changes in the time series history of vibration signals originating from various sensor locations throughout the structure. The purpose of this paper is to document the application of vibration based fault detection methods applied to several structures. Overall, this paper demonstrates the utility of vibration based methods for fault detection in a controlled laboratory setting and limitations of applying the same methods to a similar structure during flight on an experimental subscale aircraft.

  13. Late Quaternary Faulting in Southeastern Louisiana: A Natural Laboratory for Understanding Shallow Faulting in Deltaic Materials

    NASA Astrophysics Data System (ADS)

    Dawers, N. H.; McLindon, C.

    2017-12-01

    A synthesis of late Quaternary faults within the Mississippi River deltaic plain aims to provide a more accurate assessment of regional and local fault architecture, and interactions between faulting, sediment loading, salt withdrawal and compaction. This effort was initiated by the New Orleans Geological Society and has resulted in access to industry 3d seismic reflection data, as well as fault trace maps, and various types of well data and biostratigraphy. An unexpected outgrowth of this project is a hypothesis that gravity-driven normal faults in deltaic settings may be good candidates for shallow aseismic and slow-slip phenomena. The late Quaternary fault population is characterized by several large, highly segmented normal fault arrays: the Baton Rouge-Tepetate fault zone, the Lake Pontchartrain-Lake Borgne fault zone, the Golden Meadow fault zone (GMFZ), and a major counter-regional salt withdrawal structure (the Bay Marchand-Timbalier Bay-Caillou Island salt complex and West Delta fault zone) that lies just offshore of southeastern Louisiana. In comparison to the other, more northerly fault zones, the GMFZ is still significantly salt-involved. Salt structures segment the GMFZ with fault tips ending near or within salt, resulting in highly localized fault and compaction related subsidence separated by shallow salt structures, which are inherently buoyant and virtually incompressible. At least several segments within the GMFZ are characterized by marsh breaks that formed aseismically over timescales of days to months, such as near Adams Bay and Lake Enfermer. One well-documented surface rupture adjacent to a salt dome propagated over a 3 day period in 1943. We suggest that Louisiana's coastal faults make excellent analogues for deltaic faults in general, and propose that a series of positive feedbacks keep them active in the near surface. These include differential sediment loading and compaction, weak fault zone materials, high fluid pressure, low elastic

  14. Upper crustal fault reactivation and the potential of triggered earthquakes on the Atacama Fault System, N-Chile

    NASA Astrophysics Data System (ADS)

    Victor, Pia; Ewiak, Oktawian; Thomas, Ziegenhagen; Monika, Sobiesiak; Bernd, Schurr; Gabriel, Gonzalez; Onno, Oncken

    2016-04-01

    The Atacama Fault System (AFS) is an active trench-parallel fault system, located in the forearc of N-Chile directly above the subduction zone interface. Due to its well-exposed position in the hyper arid forearc of N-Chile it is the perfect target to investigate the interaction between the deformation cycle in the overriding forearc and the subduction zone seismic cycle of the underlying megathrust. Although the AFS and large parts of the upper crust are devoid of any noteworthy seismicity, at least three M=7 earthquakes in the past 10 ky have been documented in the paleoseismological record, demonstrating the potential of large events in the future. We apply a two-fold approach to explore fault activation and reactivation patterns through time and to investigate the triggering potential of upper crustal faults. 1) A new methodology using high-resolution topographic data allows us to investigate the number of past earthquakes for any given segment of the fault system as well as the amount of vertical displacement of the last increment. This provides us with a detailed dataset of past earthquake rupture of upper plate faults which is potentially linked to large subduction zone earthquakes. 2) The IPOC Creepmeter array (http://www.ipoc-network.org/index.php/observatory/creepmeter.html) provides us with high-resolution time series of fault displacement accumulation for 11 stations along the 4 most active branches of the AFS. This array monitors the displacement across the fault with 2 samples/min with a resolution of 1μm. Collocated seismometers record the seismicity at two of the creepmeters, whereas the regional seismicity is provided by the IPOC Seismological Networks. Continuous time series of the creepmeter stations since 2009 show that the shallow segments of the fault do not creep permanently. Instead the accumulation of permanent deformation occurs by triggered slip caused by local or remote earthquakes. The 2014 Mw=8.2 Pisagua Earthquake, located close to

  15. Multi-Fault Diagnosis of Rolling Bearings via Adaptive Projection Intrinsically Transformed Multivariate Empirical Mode Decomposition and High Order Singular Value Decomposition.

    PubMed

    Yuan, Rui; Lv, Yong; Song, Gangbing

    2018-04-16

    Rolling bearings are important components in rotary machinery systems. In the field of multi-fault diagnosis of rolling bearings, the vibration signal collected from single channels tends to miss some fault characteristic information. Using multiple sensors to collect signals at different locations on the machine to obtain multivariate signal can remedy this problem. The adverse effect of a power imbalance between the various channels is inevitable, and unfavorable for multivariate signal processing. As a useful, multivariate signal processing method, Adaptive-projection has intrinsically transformed multivariate empirical mode decomposition (APIT-MEMD), and exhibits better performance than MEMD by adopting adaptive projection strategy in order to alleviate power imbalances. The filter bank properties of APIT-MEMD are also adopted to enable more accurate and stable intrinsic mode functions (IMFs), and to ease mode mixing problems in multi-fault frequency extractions. By aligning IMF sets into a third order tensor, high order singular value decomposition (HOSVD) can be employed to estimate the fault number. The fault correlation factor (FCF) analysis is used to conduct correlation analysis, in order to determine effective IMFs; the characteristic frequencies of multi-faults can then be extracted. Numerical simulations and the application of multi-fault situation can demonstrate that the proposed method is promising in multi-fault diagnoses of multivariate rolling bearing signal.

  16. Crustal Structure and Seismicity along the Central Alpine Fault: Results from the WIZARD Array

    NASA Astrophysics Data System (ADS)

    Thurber, C. H.; Roecker, S. W.; Townend, J.; Bannister, S. C.; Guo, B.; Rawles, C.; Feenstra, J. P.

    2015-12-01

    In 2012 and 2013, the University of Wisconsin-Madison (UW), Rensselaer Polytechnic Institute (RPI), and Victoria University of Wellington (VUW) operated a 20-station temporary seismic array along the obliquely slipping Alpine Fault on the South Island of New Zealand. The stations of the array, nicknamed WIZARD, were deployed mainly north and east of the Deep Fault Drilling Program (DFDP) borehole site in Whataroa Valley (DFPD-2). WIZARD complemented the station distribution of the Southern Alps Microearthquake Borehole Array (SAMBA) operated by VUW, situated south and west of DFDP-2. Three additional temporary stations were deployed to the north and east of WIZARD by GNS Science, and four GeoNet permanent stations fell within the footprint of our study area. The main goals of the WIZARD project are to image the crustal structure in the region surrounding the DFDP-2 site, relocate earthquakes as precisely and accurately as possible, and determine focal mechanisms for the larger earthquakes, in order to characterize the Alpine Fault and its geometry at depth. Some previous studies had identified the area covered by WIZARD to be largely aseismic, but we have in fact located roughly 500 earthquakes underneath WIZARD. A new automatic S-wave picker proved to be very effective for rapidly increasing the size of our S-wave arrival dataset. Our tomographic inversion results show that significant velocity contrasts in both Vp and Vs (hanging wall fast) appear to delineate the Alpine Fault at depth in most of our study region, dipping typically about 60 degrees SE, and some focal mechanisms show oblique slip. However, we are not able to identify earthquakes that are actually occurring on the Alpine Fault with certainty based only on our location results.

  17. Identification of active fault using analysis of derivatives with vertical second based on gravity anomaly data (Case study: Seulimeum fault in Sumatera fault system)

    NASA Astrophysics Data System (ADS)

    Hududillah, Teuku Hafid; Simanjuntak, Andrean V. H.; Husni, Muhammad

    2017-07-01

    Gravity is a non-destructive geophysical technique that has numerous application in engineering and environmental field like locating a fault zone. The purpose of this study is to spot the Seulimeum fault system in Iejue, Aceh Besar (Indonesia) by using a gravity technique and correlate the result with geologic map and conjointly to grasp a trend pattern of fault system. An estimation of subsurface geological structure of Seulimeum fault has been done by using gravity field anomaly data. Gravity anomaly data which used in this study is from Topex that is processed up to Free Air Correction. The step in the Next data processing is applying Bouger correction and Terrin Correction to obtain complete Bouger anomaly that is topographically dependent. Subsurface modeling is done using the Gav2DC for windows software. The result showed a low residual gravity value at a north half compared to south a part of study space that indicated a pattern of fault zone. Gravity residual was successfully correlate with the geologic map that show the existence of the Seulimeum fault in this study space. The study of earthquake records can be used for differentiating the active and non active fault elements, this gives an indication that the delineated fault elements are active.

  18. Estimation of Faults in DC Electrical Power System

    NASA Technical Reports Server (NTRS)

    Gorinevsky, Dimitry; Boyd, Stephen; Poll, Scott

    2009-01-01

    This paper demonstrates a novel optimization-based approach to estimating fault states in a DC power system. Potential faults changing the circuit topology are included along with faulty measurements. Our approach can be considered as a relaxation of the mixed estimation problem. We develop a linear model of the circuit and pose a convex problem for estimating the faults and other hidden states. A sparse fault vector solution is computed by using 11 regularization. The solution is computed reliably and efficiently, and gives accurate diagnostics on the faults. We demonstrate a real-time implementation of the approach for an instrumented electrical power system testbed, the ADAPT testbed at NASA ARC. The estimates are computed in milliseconds on a PC. The approach performs well despite unmodeled transients and other modeling uncertainties present in the system.

  19. Quaternary Geology and Surface Faulting Hazard: Active and Capable Faults in Central Apennines, Italy

    NASA Astrophysics Data System (ADS)

    Falcucci, E.; Gori, S.

    2015-12-01

    The 2009 L'Aquila earthquake (Mw 6.1), in central Italy, raised the issue of surface faulting hazard in Italy, since large urban areas were affected by surface displacement along the causative structure, the Paganica fault. Since then, guidelines for microzonation were drew up that take into consideration the problem of surface faulting in Italy, and laying the bases for future regulations about related hazard, similarly to other countries (e.g. USA). More specific guidelines on the management of areas affected by active and capable faults (i.e. able to produce surface faulting) are going to be released by National Department of Civil Protection; these would define zonation of areas affected by active and capable faults, with prescriptions for land use planning. As such, the guidelines arise the problem of the time interval and general operational criteria to asses fault capability for the Italian territory. As for the chronology, the review of the international literature and regulatory allowed Galadini et al. (2012) to propose different time intervals depending on the ongoing tectonic regime - compressive or extensional - which encompass the Quaternary. As for the operational criteria, the detailed analysis of the large amount of works dealing with active faulting in Italy shows that investigations exclusively based on surface morphological features (e.g. fault planes exposition) or on indirect investigations (geophysical data), are not sufficient or even unreliable to define the presence of an active and capable fault; instead, more accurate geological information on the Quaternary space-time evolution of the areas affected by such tectonic structures is needed. A test area for which active and capable faults can be first mapped based on such a classical but still effective methodological approach can be the central Apennines. Reference Galadini F., Falcucci E., Galli P., Giaccio B., Gori S., Messina P., Moro M., Saroli M., Scardia G., Sposato A. (2012). Time

  20. Identification and location of catenary insulator in complex background based on machine vision

    NASA Astrophysics Data System (ADS)

    Yao, Xiaotong; Pan, Yingli; Liu, Li; Cheng, Xiao

    2018-04-01

    It is an important premise to locate insulator precisely for fault detection. Current location algorithms for insulator under catenary checking images are not accurate, a target recognition and localization method based on binocular vision combined with SURF features is proposed. First of all, because of the location of the insulator in complex environment, using SURF features to achieve the coarse positioning of target recognition; then Using binocular vision principle to calculate the 3D coordinates of the object which has been coarsely located, realization of target object recognition and fine location; Finally, Finally, the key is to preserve the 3D coordinate of the object's center of mass, transfer to the inspection robot to control the detection position of the robot. Experimental results demonstrate that the proposed method has better recognition efficiency and accuracy, can successfully identify the target and has a define application value.

  1. Faulting along the southern margin of Reelfoot Lake, Tennessee

    USGS Publications Warehouse

    Van Arsdale, R.; Purser, J.; Stephenson, W.; Odum, J.

    1998-01-01

    The Reelfoot Lake basin, Tennessee, is structurally complex and of great interest seismologically because it is located at the junction of two seismicity trends of the New Madrid seismic zone. To better understand the structure at this location, a 7.5-km-long seismic reflection profile was acquired on roads along the southern margin of Reelfoot Lake. The seismic line reveals a westerly dipping basin bounded on the west by the Reelfoot reverse fault zone, the Ridgely right-lateral transpressive fault zone on the east, and the Cottonwood Grove right-lateral strike-slip fault in the middle of the basin. The displacement history of the Reelfoot fault zone appears to be the same as the Ridgely fault zone, thus suggesting that movement on these fault zones has been synchronous, perhaps since the Cretaceous. Since the Reelfoot and Ridgely fault systems are believed responsible for two of the mainshocks of 1811-1812, the fault history revealed in the Reelfoot Lake profile suggests that multiple mainshocks may be typical of the New Madrid seismic zone. The Ridgely fault zone consists of two northeast-striking faults that lie at the base of and within the Mississippi Valley bluff line. This fault zone has 15 m of post-Eocene, up-to-the-east displacement and appears to locally control the eastern limit of Mississippi River migration. The Cottonwood Grove fault zone passes through the center of the seismic line and has approximately 5 m up-to-the-east displacement. Correlation of the Cottonwood Grove fault with a possible fault scarp on the floor of Reelfoot Lake and the New Markham fault north of the lake suggests the Cottonwood Grove fault may change to a northerly strike at Reelfoot Lake, thereby linking the northeast-trending zones of seismicity in the New Madrid seismic zone.

  2. Modelling Fault Zone Evolution: Implications for fluid flow.

    NASA Astrophysics Data System (ADS)

    Moir, H.; Lunn, R. J.; Shipton, Z. K.

    2009-04-01

    which compare well to features observed in mapped exposures. For these simple simulations from a small number of pre-existing joints the fault zone evolves in a predictable way: fault linkage is governed by three key factors: Stress ratio of s1 (maximum compressive stress) to s3(minimum compressive stress), original geometry of the pre-existing structures (contractional vs. dilational geometries) and the orientation of the principle stress direction (σ1) to the pre-existing structures. In this paper we present numerical simulations of the temporal and spatial evolution of fault linkage structures from many pre-existing joints. The initial location, size and orientations of these joints are based on field observations of cooling joints in granite from the Sierra Nevada. We show that the constantly evolving geometry and local stress field perturbations contribute significantly to fault zone evolution. The location and orientations of linkage structures previously predicted by the simple simulations are consistent with the predicted geometries in the more complex fault zones, however, the exact location at which individual structures form is not easily predicted. Markedly different fault zone geometries are predicted when the pre-existing joints are rotated with respect to the maximum compressive stress. In particular, fault surfaces range from evolving smooth linear structures to producing complex ‘stepped' fault zone geometries. These geometries have a significant effect on simulations of along and across-fault flow.

  3. A Method to Simultaneously Detect the Current Sensor Fault and Estimate the State of Energy for Batteries in Electric Vehicles.

    PubMed

    Xu, Jun; Wang, Jing; Li, Shiying; Cao, Binggang

    2016-08-19

    Recently, State of energy (SOE) has become one of the most fundamental parameters for battery management systems in electric vehicles. However, current information is critical in SOE estimation and current sensor is usually utilized to obtain the latest current information. However, if the current sensor fails, the SOE estimation may be confronted with large error. Therefore, this paper attempts to make the following contributions: Current sensor fault detection and SOE estimation method is realized simultaneously. Through using the proportional integral observer (PIO) based method, the current sensor fault could be accurately estimated. By taking advantage of the accurate estimated current sensor fault, the influence caused by the current sensor fault can be eliminated and compensated. As a result, the results of the SOE estimation will be influenced little by the fault. In addition, the simulation and experimental workbench is established to verify the proposed method. The results indicate that the current sensor fault can be estimated accurately. Simultaneously, the SOE can also be estimated accurately and the estimation error is influenced little by the fault. The maximum SOE estimation error is less than 2%, even though the large current error caused by the current sensor fault still exists.

  4. Delineating Concealed Faults within Cogdell Oil Field via Earthquake Detection

    NASA Astrophysics Data System (ADS)

    Aiken, C.; Walter, J. I.; Brudzinski, M.; Skoumal, R.; Savvaidis, A.; Frohlich, C.; Borgfeldt, T.; Dotray, P.

    2016-12-01

    Cogdell oil field, located within the Permian Basin of western Texas, has experienced several earthquakes ranging from magnitude 1.7 to 4.6, most of which were recorded since 2006. Using the Earthscope USArray, Gan and Frohlich [2013] relocated some of these events and found a positive correlation in the timing of increased earthquake activity and increased CO2 injection volume. However, focal depths of these earthquakes are unknown due to 70 km station spacing of the USArray. Accurate focal depths as well as new detections can delineate subsurface faults and establish whether earthquakes are occurring in the shallow sediments or in the deeper basement. To delineate subsurface fault(s) in this region, we first detect earthquakes not currently listed in the USGS catalog by applying continuous waveform-template matching algorithms to multiple seismic data sets. We utilize seismic data spanning the time frame of 2006 to 2016 - which includes data from the U.S. Geological Survey Global Seismographic Network, the USArray, and the Sweetwater, TX broadband and nodal array located 20-40 km away. The catalog of earthquakes enhanced by template matching reveals events that were well recorded by the large-N Sweetwater array, so we are experimenting with strategies for optimizing template matching using different configurations of many stations. Since earthquake activity in the Cogdell oil field is on-going (a magnitude 2.6 occurred on May 29, 2016), a temporary deployment of TexNet seismometers has been planned for the immediate vicinity of Cogdell oil field in August 2016. Results on focal depths and detection of small magnitude events are pending this small local network deployment.

  5. Seismicity and Tectonics of the West Kaibab Fault Zone, AZ

    NASA Astrophysics Data System (ADS)

    Wilgus, J. T.; Brumbaugh, D. S.

    2014-12-01

    The West Kaibab Fault Zone (WKFZ) is the westernmost bounding structure of the Kaibab Plateau of northern Arizona. The WKFZ is a branching complex of high angle, normal faults downthrown to the west. There are three main faults within the WKFZ, the Big Springs fault with a maximum of 165 m offset, the Muav fault with 350 m of displacement, and the North Road fault having a maximum throw of approximately 90 m. Mapping of geologically recent surface deposits at or crossing the fault contacts indicates that the faults are likely Quaternary with the most recent offsets occurring <1.6 Ma. Slip rates are estimated to be less than 0.2 mm/yr. No historic fault slip has been documented. The WKFZ is one of the most seismically active areas in Arizona and lies within the Northern Arizona Seismic Belt (NASB), which stretches across northern Arizona trending NW-SE. The data set for this study includes 156 well documented events with the largest being a M5.75 in 1959 and including a swarm of seven earthquakes in 2012. The seismic data set (1934-2014) reveals that seismic activity clusters in two regions within the study area, the Fredonia cluster located in the NW corner of the study area and the Kaibab cluster located in the south central portion of the study area. The fault plane solutions to date indicate NE-SW to EW extension is occurring in the study area. Source relationships between earthquakes and faults within the WKFZ have not previously been studied in detail. The goal of this study is to use the seismic data set, the available data on faults, and the regional physiography to search for source relationships for the seismicity. Analysis includes source parameters of the earthquake data (location, depth, and fault plane solutions), and comparison of this output to the known faults and areal physiographic framework to indicate any active faults of the WKFZ, or suggested active unmapped faults. This research contributes to a better understanding of the present nature of

  6. An update of Quaternary faults of central and eastern Oregon

    USGS Publications Warehouse

    Weldon, Ray J.; Fletcher, D.K.; Weldon, E.M.; Scharer, K.M.; McCrory, P.A.

    2002-01-01

    This is the online version of a CD-ROM publication. We have updated the eastern portion of our previous active fault map of Oregon (Pezzopane, Nakata, and Weldon, 1992) as a contribution to the larger USGS effort to produce digital maps of active faults in the Pacific Northwest region. The 1992 fault map has seen wide distribution and has been reproduced in essentially all subsequent compilations of active faults of Oregon. The new map provides a substantial update of known active or suspected active faults east of the Cascades. Improvements in the new map include (1) many newly recognized active faults, (2) a linked ArcInfo map and reference database, (3) more precise locations for previously recognized faults on shaded relief quadrangles generated from USGS 30-m digital elevations models (DEM), (4) more uniform coverage resulting in more consistent grouping of the ages of active faults, and (5) a new category of 'possibly' active faults that share characteristics with known active faults, but have not been studied adequately to assess their activity. The distribution of active faults has not changed substantially from the original Pezzopane, Nakata and Weldon map. Most faults occur in the south-central Basin and Range tectonic province that is located in the backarc portion of the Cascadia subduction margin. These faults occur in zones consisting of numerous short faults with similar rates, ages, and styles of movement. Many active faults strongly correlate with the most active volcanic centers of Oregon, including Newberry Craters and Crater Lake.

  7. Seismic Hazard and Fault Length

    NASA Astrophysics Data System (ADS)

    Black, N. M.; Jackson, D. D.; Mualchin, L.

    2005-12-01

    If mx is the largest earthquake magnitude that can occur on a fault, then what is mp, the largest magnitude that should be expected during the planned lifetime of a particular structure? Most approaches to these questions rely on an estimate of the Maximum Credible Earthquake, obtained by regression (e.g. Wells and Coppersmith, 1994) of fault length (or area) and magnitude. Our work differs in two ways. First, we modify the traditional approach to measuring fault length, to allow for hidden fault complexity and multi-fault rupture. Second, we use a magnitude-frequency relationship to calculate the largest magnitude expected to occur within a given time interval. Often fault length is poorly defined and multiple faults rupture together in a single event. Therefore, we need to expand the definition of a mapped fault length to obtain a more accurate estimate of the maximum magnitude. In previous work, we compared fault length vs. rupture length for post-1975 earthquakes in Southern California. In this study, we found that mapped fault length and rupture length are often unequal, and in several cases rupture broke beyond the previously mapped fault traces. To expand the geologic definition of fault length we outlined several guidelines: 1) if a fault truncates at young Quaternary alluvium, the fault line should be inferred underneath the younger sediments 2) faults striking within 45° of one another should be treated as a continuous fault line and 3) a step-over can link together faults at least 5 km apart. These definitions were applied to fault lines in Southern California. For example, many of the along-strike faults lines in the Mojave Desert are treated as a single fault trending from the Pinto Mountain to the Garlock fault. In addition, the Rose Canyon and Newport-Inglewood faults are treated as a single fault line. We used these more generous fault lengths, and the Wells and Coppersmith regression, to estimate the maximum magnitude (mx) for the major faults in

  8. A seismic fault recognition method based on ant colony optimization

    NASA Astrophysics Data System (ADS)

    Chen, Lei; Xiao, Chuangbai; Li, Xueliang; Wang, Zhenli; Huo, Shoudong

    2018-05-01

    Fault recognition is an important section in seismic interpretation and there are many methods for this technology, but no one can recognize fault exactly enough. For this problem, we proposed a new fault recognition method based on ant colony optimization which can locate fault precisely and extract fault from the seismic section. Firstly, seismic horizons are extracted by the connected component labeling algorithm; secondly, the fault location are decided according to the horizontal endpoints of each horizon; thirdly, the whole seismic section is divided into several rectangular blocks and the top and bottom endpoints of each rectangular block are considered as the nest and food respectively for the ant colony optimization algorithm. Besides that, the positive section is taken as an actual three dimensional terrain by using the seismic amplitude as a height. After that, the optimal route from nest to food calculated by the ant colony in each block is judged as a fault. Finally, extensive comparative tests were performed on the real seismic data. Availability and advancement of the proposed method were validated by the experimental results.

  9. Dynamic earthquake rupture simulations on nonplanar faults embedded in 3D geometrically complex, heterogeneous elastic solids

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Duru, Kenneth, E-mail: kduru@stanford.edu; Dunham, Eric M.; Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA

    Dynamic propagation of shear ruptures on a frictional interface in an elastic solid is a useful idealization of natural earthquakes. The conditions relating discontinuities in particle velocities across fault zones and tractions acting on the fault are often expressed as nonlinear friction laws. The corresponding initial boundary value problems are both numerically and computationally challenging. In addition, seismic waves generated by earthquake ruptures must be propagated for many wavelengths away from the fault. Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods. We present a high order accurate finite difference method for: a)more » enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration; b) dynamic propagation of earthquake ruptures along nonplanar faults; and c) accurate propagation of seismic waves in heterogeneous media with free surface topography. We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts (SBP) finite difference operators in space. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. The finite difference stencils used in this paper are sixth order accurate in the interior and third order accurate close to the boundaries. However, the method is applicable to any spatial operator with a diagonal norm satisfying the SBP property. Time stepping is performed with a 4th order accurate explicit low storage Runge–Kutta scheme, thus yielding a globally fourth order accurate method in both space and time. We show numerical simulations on band limited self-similar fractal faults revealing the complexity of rupture

  10. Dynamic earthquake rupture simulations on nonplanar faults embedded in 3D geometrically complex, heterogeneous elastic solids

    NASA Astrophysics Data System (ADS)

    Duru, Kenneth; Dunham, Eric M.

    2016-01-01

    Dynamic propagation of shear ruptures on a frictional interface in an elastic solid is a useful idealization of natural earthquakes. The conditions relating discontinuities in particle velocities across fault zones and tractions acting on the fault are often expressed as nonlinear friction laws. The corresponding initial boundary value problems are both numerically and computationally challenging. In addition, seismic waves generated by earthquake ruptures must be propagated for many wavelengths away from the fault. Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods. We present a high order accurate finite difference method for: a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration; b) dynamic propagation of earthquake ruptures along nonplanar faults; and c) accurate propagation of seismic waves in heterogeneous media with free surface topography. We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts (SBP) finite difference operators in space. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. The finite difference stencils used in this paper are sixth order accurate in the interior and third order accurate close to the boundaries. However, the method is applicable to any spatial operator with a diagonal norm satisfying the SBP property. Time stepping is performed with a 4th order accurate explicit low storage Runge-Kutta scheme, thus yielding a globally fourth order accurate method in both space and time. We show numerical simulations on band limited self-similar fractal faults revealing the complexity of rupture dynamics

  11. Active faulting on the Wallula fault zone within the Olympic-Wallowa lineament, Washington State, USA

    USGS Publications Warehouse

    Sherrod, Brian; Blakely, Richard J.; Lasher, John P.; Lamb, Andrew P.; Mahan, Shannon; Foit, Franklin F.; Barnett, Elizabeth

    2016-01-01

    The Wallula fault zone is an integral feature of the Olympic-Wallowa lineament, an ∼500-km-long topographic lineament oblique to the Cascadia plate boundary, extending from Vancouver Island, British Columbia, to Walla Walla, Washington. The structure and past earthquake activity of the Wallula fault zone are important because of nearby infrastructure, and also because the fault zone defines part of the Olympic-Wallowa lineament in south-central Washington and suggests that the Olympic-Wallowa lineament may have a structural origin. We used aeromagnetic and ground magnetic data to locate the trace of the Wallula fault zone in the subsurface and map a quarry exposure of the Wallula fault zone near Finley, Washington, to investigate past earthquakes along the fault. We mapped three main packages of rocks and unconsolidated sediments in an ∼10-m-high quarry exposure. Our mapping suggests at least three late Pleistocene earthquakes with surface rupture, and an episode of liquefaction in the Holocene along the Wallula fault zone. Faint striae on the master fault surface are subhorizontal and suggest reverse dextral oblique motion for these earthquakes, consistent with dextral offset on the Wallula fault zone inferred from offset aeromagnetic anomalies associated with ca. 8.5 Ma basalt dikes. Magnetic surveys show that the Wallula fault actually lies 350 m to the southwest of the trace shown on published maps, passes directly through deformed late Pleistocene or younger deposits exposed at Finley quarry, and extends uninterrupted over 120 km.

  12. Application of Fault Tree Analysis and Fuzzy Neural Networks to Fault Diagnosis in the Internet of Things (IoT) for Aquaculture.

    PubMed

    Chen, Yingyi; Zhen, Zhumi; Yu, Huihui; Xu, Jing

    2017-01-14

    In the Internet of Things (IoT) equipment used for aquaculture is often deployed in outdoor ponds located in remote areas. Faults occur frequently in these tough environments and the staff generally lack professional knowledge and pay a low degree of attention in these areas. Once faults happen, expert personnel must carry out maintenance outdoors. Therefore, this study presents an intelligent method for fault diagnosis based on fault tree analysis and a fuzzy neural network. In the proposed method, first, the fault tree presents a logic structure of fault symptoms and faults. Second, rules extracted from the fault trees avoid duplicate and redundancy. Third, the fuzzy neural network is applied to train the relationship mapping between fault symptoms and faults. In the aquaculture IoT, one fault can cause various fault symptoms, and one symptom can be caused by a variety of faults. Four fault relationships are obtained. Results show that one symptom-to-one fault, two symptoms-to-two faults, and two symptoms-to-one fault relationships can be rapidly diagnosed with high precision, while one symptom-to-two faults patterns perform not so well, but are still worth researching. This model implements diagnosis for most kinds of faults in the aquaculture IoT.

  13. Application of Fault Tree Analysis and Fuzzy Neural Networks to Fault Diagnosis in the Internet of Things (IoT) for Aquaculture

    PubMed Central

    Chen, Yingyi; Zhen, Zhumi; Yu, Huihui; Xu, Jing

    2017-01-01

    In the Internet of Things (IoT) equipment used for aquaculture is often deployed in outdoor ponds located in remote areas. Faults occur frequently in these tough environments and the staff generally lack professional knowledge and pay a low degree of attention in these areas. Once faults happen, expert personnel must carry out maintenance outdoors. Therefore, this study presents an intelligent method for fault diagnosis based on fault tree analysis and a fuzzy neural network. In the proposed method, first, the fault tree presents a logic structure of fault symptoms and faults. Second, rules extracted from the fault trees avoid duplicate and redundancy. Third, the fuzzy neural network is applied to train the relationship mapping between fault symptoms and faults. In the aquaculture IoT, one fault can cause various fault symptoms, and one symptom can be caused by a variety of faults. Four fault relationships are obtained. Results show that one symptom-to-one fault, two symptoms-to-two faults, and two symptoms-to-one fault relationships can be rapidly diagnosed with high precision, while one symptom-to-two faults patterns perform not so well, but are still worth researching. This model implements diagnosis for most kinds of faults in the aquaculture IoT. PMID:28098822

  14. Fault patterns in the Strait of Messina, Southern Italy

    NASA Astrophysics Data System (ADS)

    Fu, L.; Krastel, S.; Chiocci, F. L.; Ridente, D.; Schulten, I.; Cukur, D.; Gross, F.; Bialas, J.

    2013-12-01

    The Strait of Messina is one of the seismically most active areas in the Mediterranean region. The structural and seismotectonic settings of the area are still poorly understood. A number of faults have been identified on new high-resolution 2D seismic data collected in December 2011/January 2012. Most of the faults trending NWW-SEE are high angle (>60°) faults; they are located in the northern (off Calabria) and southern part of the Messina Straits. A number of faults identified in the central part of the Straits along the central channel or on the Calabrian side strike NNE-SSW or NNW-NNE. They dip at intermediate (30°-60°) to low (<30°) angles. The NNW-ward motion of Sicily and the NE-ward motion of Calabria indicate that faults in the strait are transtensional and that the strait is basically an asymmetric pull-apart basin (half-graben) under transtensional condition. This is confirmed by the appearances of negative flower structures, an en-echelon fault zone, and two main depocentres in the northern and central part of the straits, respectively. A fault located close to the Sicilian coast between Taormina and Briga may represent the so called Taormina fault. The existence of this fault is heavily debated in literatures. As the Strait of Messina is a transtensional basin, the Taormina fault should be a surface fault, which may outcrop very close to the Ionian coast off Sicily rather than a blind basement fault as identified on our data. Faults in the north may be the source of the 1908 Messina earthquake, because the area is in an early mature developing stage of a pull-apart basin. The cross-basin faults transecting this part of the basin would increase the slippage and the potential for large-magnitude earthquakes.

  15. High stresses stored in fault zones: example of the Nojima fault (Japan)

    NASA Astrophysics Data System (ADS)

    Boullier, Anne-Marie; Robach, Odile; Ildefonse, Benoît; Barou, Fabrice; Mainprice, David; Ohtani, Tomoyuki; Fujimoto, Koichiro

    2018-04-01

    During the last decade pulverized rocks have been described on outcrops along large active faults and attributed to damage related to a propagating seismic rupture front. Questions remain concerning the maximal lateral distance from the fault plane and maximal depth for dynamic damage to be imprinted in rocks. In order to document these questions, a representative core sample of granodiorite located 51.3 m from the Nojima fault (Japan) that was drilled after the Hyogo-ken Nanbu (Kobe) earthquake is studied by using electron backscattered diffraction (EBSD) and high-resolution X-ray Laue microdiffraction. Although located outside of the Nojima damage fault zone and macroscopically undeformed, the sample shows pervasive microfractures and local fragmentation. These features are attributed to the first stage of seismic activity along the Nojima fault characterized by laumontite as the main sealing mineral. EBSD mapping was used in order to characterize the crystallographic orientation and deformation microstructures in the sample, and X-ray microdiffraction was used to measure elastic strain and residual stresses on each point of the mapped quartz grain. Both methods give consistent results on the crystallographic orientation and show small and short wavelength misorientations associated with laumontite-sealed microfractures and alignments of tiny fluid inclusions. Deformation microstructures in quartz are symptomatic of the semi-brittle faulting regime, in which low-temperature brittle plastic deformation and stress-driven dissolution-deposition processes occur conjointly. This deformation occurred at a 3.7-11.1 km depth interval as indicated by the laumontite stability domain. Residual stresses are calculated from deviatoric elastic strain tensor measured using X-ray Laue microdiffraction using the Hooke's law. The modal value of the von Mises stress distribution is at 100 MPa and the mean at 141 MPa. Such stress values are comparable to the peak strength of a

  16. Detection and diagnosis of bearing and cutting tool faults using hidden Markov models

    NASA Astrophysics Data System (ADS)

    Boutros, Tony; Liang, Ming

    2011-08-01

    Over the last few decades, the research for new fault detection and diagnosis techniques in machining processes and rotating machinery has attracted increasing interest worldwide. This development was mainly stimulated by the rapid advance in industrial technologies and the increase in complexity of machining and machinery systems. In this study, the discrete hidden Markov model (HMM) is applied to detect and diagnose mechanical faults. The technique is tested and validated successfully using two scenarios: tool wear/fracture and bearing faults. In the first case the model correctly detected the state of the tool (i.e., sharp, worn, or broken) whereas in the second application, the model classified the severity of the fault seeded in two different engine bearings. The success rate obtained in our tests for fault severity classification was above 95%. In addition to the fault severity, a location index was developed to determine the fault location. This index has been applied to determine the location (inner race, ball, or outer race) of a bearing fault with an average success rate of 96%. The training time required to develop the HMMs was less than 5 s in both the monitoring cases.

  17. Stress drop variation of M > 4 earthquakes on the Blanco oceanic transform fault using a phase coherence method

    NASA Astrophysics Data System (ADS)

    Williams, J. R.; Hawthorne, J.; Rost, S.; Wright, T. J.

    2017-12-01

    Earthquakes on oceanic transform faults often show unusual behaviour. They tend to occur in swarms, have large numbers of foreshocks, and have high stress drops. We estimate stress drops for approximately 60 M > 4 earthquakes along the Blanco oceanic transform fault, a right-lateral fault separating the Juan de Fuca and Pacific plates offshore of Oregon. We find stress drops with a median of 4.4±19.3MPa and examine how they vary with earthquake moment. We calculate stress drops using a recently developed method based on inter-station phase coherence. We compare seismic records of co-located earthquakes at a range of stations. At each station, we apply an empirical Green's function (eGf) approach to remove phase path effects and isolate the relative apparent source time functions. The apparent source time functions at each earthquake should vary among stations at periods shorter than a P wave's travel time across the earthquake rupture area. Therefore we compute the rupture length of the larger earthquake by identifying the frequency at which the relative apparent source time functions start to vary among stations, leading to low inter-station phase coherence. We determine a stress drop from the rupture length and moment of the larger earthquake. Our initial stress drop estimates increase with increasing moment, suggesting that earthquakes on the Blanco fault are not self-similar. However, these stress drops may be biased by several factors, including depth phases, trace alignment, and source co-location. We find that the inclusion of depth phases (such as pP) in the analysis time window has a negligible effect on the phase coherence of our relative apparent source time functions. We find that trace alignment must be accurate to within 0.05 s to allow us to identify variations in the apparent source time functions at periods relevant for M > 4 earthquakes. We check that the alignments are accurate enough by comparing P wave arrival times across groups of

  18. Paleoseismological surveys on the Hinagu fault zone in Kumamoto, central Kyushu, Japan

    NASA Astrophysics Data System (ADS)

    Azuma, T.

    2017-12-01

    The Hinagu fault zone is located on the south of the Futagawa fault zone, which was a main part of the source fault of the 2016 Kumamoto earthquake of Mj 7.3. Northernmost part of the Hinagu fault zone was also acted in 2016 event and surface faults with right-lateral displacement upto ca. 50 cm were appeared. Seismicity along the central part of the Hinagu fault was increased just after the 2016 Kumamoto Earthquake. It seems that the Hinagu fault zone would produce the next large earthquake in the near future, although it has not occurred yet. The Headquarters of the Earthquake Research Promotions (HERP) conducted active fault surveys on the Hinagu fault zone to recognize the probability of the occurrence of the next faulting event. The Hinagu fault zone is composed with 3 fault segments, Takano-Shirahata, Hinagu, and Yatsushiro Bay. Yatsushiro Bay segment is offshore fault. In FY2016, we conducted paleoseismological trenching surveys at 2 sites (Yamaide, Minamibeta) and offshore drilling. Those result showed evidences that the recurrence intervals of the Hinagu fault zone was rather short and the last faulting event occurred around 1500-2000 yrsBP. In FY2017, we are planning another trenching survey on the southern part of the central segment, where Yatsushiro city located close to the fault.

  19. Seismicity and Crustal Anisotropy Beneath the Western Segment of the North Anatolian Fault: Results from a Dense Seismic Array

    NASA Astrophysics Data System (ADS)

    Turkelli, N.; Teoman, U.; Altuncu Poyraz, S.; Cambaz, D.; Mutlu, A. K.; Kahraman, M.; Houseman, G. A.; Rost, S.; Thompson, D. A.; Cornwell, D. G.; Utkucu, M.; Gülen, L.

    2013-12-01

    The North Anatolian Fault (NAF) is one of the major strike slip fault systems on Earth comparable to San Andreas Fault in some ways. Devastating earthquakes have occurred along this system causing major damage and casualties. In order to comprehensively investigate the shallow and deep crustal structure beneath the western segment of NAF, a temporary dense seismic network for North Anatolia (DANA) consisting of 73 broadband sensors was deployed in early May 2012 surrounding a rectangular grid of by 70 km and a nominal station spacing of 7 km with the aim of further enhancing the detection capability of this dense seismic array. This joint project involves researchers from University of Leeds, UK, Bogazici University Kandilli Observatory and Earthquake Research Institute (KOERI), and University of Sakarya and primarily focuses on upper crustal studies such as earthquake locations (especially micro-seismic activity), receiver functions, moment tensor inversions, shear wave splitting, and ambient noise correlations. To begin with, we obtained the hypocenter locations of local earthquakes that occured within the DANA network. The dense 2-D grid geometry considerably enhanced the earthquake detection capability which allowed us to precisely locate events with local magnitudes (Ml) less than 1.0. Accurate earthquake locations will eventually lead to high resolution images of the upper crustal structure beneath the northern and southern branches of NAF in Sakarya region. In order to put additional constraints on the active tectonics of the western part of NAF, we also determined fault plane solutions using Regional Moment Tensor Inversion (RMT) and P wave first motion methods. For the analysis of high quality fault plane solutions, data from KOERI and the DANA project were merged. Furthermore, with the aim of providing insights on crustal anisotropy, shear wave splitting parameters such as lag time and fast polarization direction were obtained for local events recorded

  20. A dynamic integrated fault diagnosis method for power transformers.

    PubMed

    Gao, Wensheng; Bai, Cuifen; Liu, Tong

    2015-01-01

    In order to diagnose transformer fault efficiently and accurately, a dynamic integrated fault diagnosis method based on Bayesian network is proposed in this paper. First, an integrated fault diagnosis model is established based on the causal relationship among abnormal working conditions, failure modes, and failure symptoms of transformers, aimed at obtaining the most possible failure mode. And then considering the evidence input into the diagnosis model is gradually acquired and the fault diagnosis process in reality is multistep, a dynamic fault diagnosis mechanism is proposed based on the integrated fault diagnosis model. Different from the existing one-step diagnosis mechanism, it includes a multistep evidence-selection process, which gives the most effective diagnostic test to be performed in next step. Therefore, it can reduce unnecessary diagnostic tests and improve the accuracy and efficiency of diagnosis. Finally, the dynamic integrated fault diagnosis method is applied to actual cases, and the validity of this method is verified.

  1. A Dynamic Integrated Fault Diagnosis Method for Power Transformers

    PubMed Central

    Gao, Wensheng; Liu, Tong

    2015-01-01

    In order to diagnose transformer fault efficiently and accurately, a dynamic integrated fault diagnosis method based on Bayesian network is proposed in this paper. First, an integrated fault diagnosis model is established based on the causal relationship among abnormal working conditions, failure modes, and failure symptoms of transformers, aimed at obtaining the most possible failure mode. And then considering the evidence input into the diagnosis model is gradually acquired and the fault diagnosis process in reality is multistep, a dynamic fault diagnosis mechanism is proposed based on the integrated fault diagnosis model. Different from the existing one-step diagnosis mechanism, it includes a multistep evidence-selection process, which gives the most effective diagnostic test to be performed in next step. Therefore, it can reduce unnecessary diagnostic tests and improve the accuracy and efficiency of diagnosis. Finally, the dynamic integrated fault diagnosis method is applied to actual cases, and the validity of this method is verified. PMID:25685841

  2. A Method to Simultaneously Detect the Current Sensor Fault and Estimate the State of Energy for Batteries in Electric Vehicles

    PubMed Central

    Xu, Jun; Wang, Jing; Li, Shiying; Cao, Binggang

    2016-01-01

    Recently, State of energy (SOE) has become one of the most fundamental parameters for battery management systems in electric vehicles. However, current information is critical in SOE estimation and current sensor is usually utilized to obtain the latest current information. However, if the current sensor fails, the SOE estimation may be confronted with large error. Therefore, this paper attempts to make the following contributions: Current sensor fault detection and SOE estimation method is realized simultaneously. Through using the proportional integral observer (PIO) based method, the current sensor fault could be accurately estimated. By taking advantage of the accurate estimated current sensor fault, the influence caused by the current sensor fault can be eliminated and compensated. As a result, the results of the SOE estimation will be influenced little by the fault. In addition, the simulation and experimental workbench is established to verify the proposed method. The results indicate that the current sensor fault can be estimated accurately. Simultaneously, the SOE can also be estimated accurately and the estimation error is influenced little by the fault. The maximum SOE estimation error is less than 2%, even though the large current error caused by the current sensor fault still exists. PMID:27548183

  3. Long-Term Pavement Performance Automated Faulting Measurement

    DOT National Transportation Integrated Search

    2015-02-01

    This study focused on identifying transverse joint locations on jointed plain concrete pavements using an automated joint detection algorithm and computing faulting at these locations using Long-Term Pavement Performance (LTPP) Program profile data c...

  4. Computer hardware fault administration

    DOEpatents

    Archer, Charles J.; Megerian, Mark G.; Ratterman, Joseph D.; Smith, Brian E.

    2010-09-14

    Computer hardware fault administration carried out in a parallel computer, where the parallel computer includes a plurality of compute nodes. The compute nodes are coupled for data communications by at least two independent data communications networks, where each data communications network includes data communications links connected to the compute nodes. Typical embodiments carry out hardware fault administration by identifying a location of a defective link in the first data communications network of the parallel computer and routing communications data around the defective link through the second data communications network of the parallel computer.

  5. Morphostructural study of the Belledonne faults system (French Alps).

    NASA Astrophysics Data System (ADS)

    Billant, Jérémy; Bellier, Olivier; Hippolyte, Jean-Claude; Godard, Vincent; Manchuel, Kevin

    2016-04-01

    The NE trending Belledonne faults system, located in the Alps, is a potentially active faults system that extends from the Aiguilles Rouges and Mont Blanc massifs in the NE to the Vercors massif in the SW (subalpine massifs). It includes the Belledonne border fault (BBF), defined by an alignment of micro earthquakes (ML≤3.5) along the eastern part of the Grésivaudan valley (Thouvenot et al., 2003). Focal mechanisms and their respective depths tend to confirm a dextral strike-slip faulting at crustal scale. In the scope of the Sigma project (http://projet-sigma.com/index.html, EDF), this study aims at better constraining the geometry, kinematic and seismogenic potential of the constitutive faults of the Belledonne fault system, by using a multidisciplinary approach that includes tectonics, geomorphology and geophysics. Fault kinematic analysis along the BBF (Billant et al., 2015) and the Jasneuf fault allows the determination of a strike-slip tectonic regime characterised by an ENE trending σ1 stress axes, which is consistent with stress state deduced from the focal mechanisms. Although no morphological anomalies could be related to recent faulting along the BBF, new clues of potential Quaternary deformations were observed along the other faults of the system: -right lateral offset of morphologic markers (talwegs...) along the NE trending Arcalod fault located at the north-eastern terminations of the BBF; -left lateral offset of the valley formed by the Isère glacier along the NW trending Brion fault which is consistent with its left-lateral slip inferred from the focal mechanisms; -fault scarps and right lateral offsets of cliffs bordering a calcareous plateau and talwegs along the four fault segments of the NE trending Jasneuf fault located at the south-western termination of the BBF in the Vercors massif. Some offsets were measured using a new method that does not require the identification of piercing points and take advantage of the high resolution

  6. A signal-based fault detection and classification method for heavy haul wagons

    NASA Astrophysics Data System (ADS)

    Li, Chunsheng; Luo, Shihui; Cole, Colin; Spiryagin, Maksym; Sun, Yanquan

    2017-12-01

    This paper proposes a signal-based fault detection and isolation (FDI) system for heavy haul wagons considering the special requirements of low cost and robustness. The sensor network of the proposed system consists of just two accelerometers mounted on the front left and rear right of the carbody. Seven fault indicators (FIs) are proposed based on the cross-correlation analyses of the sensor-collected acceleration signals. Bolster spring fault conditions are focused on in this paper, including two different levels (small faults and moderate faults) and two locations (faults in the left and right bolster springs of the first bogie). A fully detailed dynamic model of a typical 40t axle load heavy haul wagon is developed to evaluate the deterioration of dynamic behaviour under proposed fault conditions and demonstrate the detectability of the proposed FDI method. Even though the fault conditions considered in this paper did not deteriorate the wagon dynamic behaviour dramatically, the proposed FIs show great sensitivity to the bolster spring faults. The most effective and efficient FIs are chosen for fault detection and classification. Analysis results indicate that it is possible to detect changes in bolster stiffness of ±25% and identify the fault location.

  7. Subaru FATS (fault tracking system)

    NASA Astrophysics Data System (ADS)

    Winegar, Tom W.; Noumaru, Junichi

    2000-07-01

    The Subaru Telescope requires a fault tracking system to record the problems and questions that staff experience during their work, and the solutions provided by technical experts to these problems and questions. The system records each fault and routes it to a pre-selected 'solution-provider' for each type of fault. The solution provider analyzes the fault and writes a solution that is routed back to the fault reporter and recorded in a 'knowledge-base' for future reference. The specifications of our fault tracking system were unique. (1) Dual language capacity -- Our staff speak both English and Japanese. Our contractors speak Japanese. (2) Heterogeneous computers -- Our computer workstations are a mixture of SPARCstations, Macintosh and Windows computers. (3) Integration with prime contractors -- Mitsubishi and Fujitsu are primary contractors in the construction of the telescope. In many cases, our 'experts' are our contractors. (4) Operator scheduling -- Our operators spend 50% of their work-month operating the telescope, the other 50% is spent working day shift at the base facility in Hilo, or day shift at the summit. We plan for 8 operators, with a frequent rotation. We need to keep all operators informed on the current status of all faults, no matter the operator's location.

  8. Kinematic vicissitudes and the spatial distribution of the alteration zone related to the Byobuyama fault, central Japan. (Implication; Influence of another faults.)

    NASA Astrophysics Data System (ADS)

    Katori, T.; Kobayashi, K.

    2015-12-01

    The central Japan is one of the most concentrated area of active faults (Quaternary fault). These are roughly classified into two orthogonally-oriented fault sets of NE-SW and NW-SE strikes. The study area is located in Gifu prefecture, central Japan. In there, the basement rocks are composed mainly of Triassic-Jurassic accretionary prism (Mino belt), Cretaceous Nohi Rhyolite and Cretaceous granitic rocks. Miocene Mizunami G. and Pliocene-Pleistocene Toki Sand and Gravel F. unconformably cover the basement rocks. The Byobuyama fault, 32 km in length, is NE-SW strike and displaces perpendicularly the Toki Sand and Gravel F. by 500 m. The northeastern terminal of the fault has contact with the southern terminal of the Atera fault of NW-SE strike and offset their displacements each other. It is clear that the activity of the Byobuyama fault plays a role of the development of the complicated fault geometry system in the central Japan. In this study, we performed a broad-based investigation along the Byobuyama fault and collected samples. Actually, we observed 400 faults and analyzed 200 fault rocks. Based on these results, we obtained the following new opinion. 1. The Byobuyama fault has experienced following activities that can be divided to 3 stages at least under different stress field. 1) Movement with the sinisterly sense (preserved in cataclasite zone). 2) Dextral movement (preserved in fault gouge zone). 3) Reverse fault movement (due to the aggressive rise of mountains). In addition, the change from Stage 2 to Stage 3 is a continuous. 2. There is a relationship between the distance from the trace of the Byobuyama fault and the combination of alteration minerals included in the fault rocks. 3. In the central part of the Byobuyama fault (CPBF), fault plane trend and combination of alteration minerals shows specific features. The continuous change is considered to mean the presence of factors that interfere with the dextral movement of the Byobuyama fault. What is

  9. Fault Identification by Unsupervised Learning Algorithm

    NASA Astrophysics Data System (ADS)

    Nandan, S.; Mannu, U.

    2012-12-01

    Contemporary fault identification techniques predominantly rely on the surface expression of the fault. This biased observation is inadequate to yield detailed fault structures in areas with surface cover like cities deserts vegetation etc and the changes in fault patterns with depth. Furthermore it is difficult to estimate faults structure which do not generate any surface rupture. Many disastrous events have been attributed to these blind faults. Faults and earthquakes are very closely related as earthquakes occur on faults and faults grow by accumulation of coseismic rupture. For a better seismic risk evaluation it is imperative to recognize and map these faults. We implement a novel approach to identify seismically active fault planes from three dimensional hypocenter distribution by making use of unsupervised learning algorithms. We employ K-means clustering algorithm and Expectation Maximization (EM) algorithm modified to identify planar structures in spatial distribution of hypocenter after filtering out isolated events. We examine difference in the faults reconstructed by deterministic assignment in K- means and probabilistic assignment in EM algorithm. The method is conceptually identical to methodologies developed by Ouillion et al (2008, 2010) and has been extensively tested on synthetic data. We determined the sensitivity of the methodology to uncertainties in hypocenter location, density of clustering and cross cutting fault structures. The method has been applied to datasets from two contrasting regions. While Kumaon Himalaya is a convergent plate boundary, Koyna-Warna lies in middle of the Indian Plate but has a history of triggered seismicity. The reconstructed faults were validated by examining the fault orientation of mapped faults and the focal mechanism of these events determined through waveform inversion. The reconstructed faults could be used to solve the fault plane ambiguity in focal mechanism determination and constrain the fault

  10. Fault linkage and continental breakup

    NASA Astrophysics Data System (ADS)

    Cresswell, Derren; Lymer, Gaël; Reston, Tim; Stevenson, Carl; Bull, Jonathan; Sawyer, Dale; Morgan, Julia

    2017-04-01

    The magma-poor rifted margin off the west coast of Galicia (NW Spain) has provided some of the key observations in the development of models describing the final stages of rifting and continental breakup. In 2013, we collected a 68 x 20 km 3D seismic survey across the Galicia margin, NE Atlantic. Processing through to 3D Pre-stack Time Migration (12.5 m bin-size) and 3D depth conversion reveals the key structures, including an underlying detachment fault (the S detachment), and the intra-block and inter-block faults. These data reveal multiple phases of faulting, which overlap spatially and temporally, have thinned the crust to between zero and a few km thickness, producing 'basement windows' where crustal basement has been completely pulled apart and sediments lie directly on the mantle. Two approximately N-S trending fault systems are observed: 1) a margin proximal system of two linked faults that are the upward extension (breakaway faults) of the S; in the south they form one surface that splays northward to form two faults with an intervening fault block. These faults were thus demonstrably active at one time rather than sequentially. 2) An oceanward relay structure that shows clear along strike linkage. Faults within the relay trend NE-SW and heavily dissect the basement. The main block bounding faults can be traced from the S detachment through the basement into, and heavily deforming, the syn-rift sediments where they die out, suggesting that the faults propagated up from the S detachment surface. Analysis of the fault heaves and associated maps at different structural levels show complementary fault systems. The pattern of faulting suggests a variation in main tectonic transport direction moving oceanward. This might be interpreted as a temporal change during sequential faulting, however the transfer of extension between faults and the lateral variability of fault blocks suggests that many of the faults across the 3D volume were active at least in part

  11. Tsunami simulations of the 1867 Virgin Island earthquake: Constraints on epicenter location and fault parameters

    USGS Publications Warehouse

    Barkan, Roy; ten Brink, Uri S.

    2010-01-01

    The 18 November 1867 Virgin Island earthquake and the tsunami that closely followed caused considerable loss of life and damage in several places in the northeast Caribbean region. The earthquake was likely a manifestation of the complex tectonic deformation of the Anegada Passage, which cuts across the Antilles island arc between the Virgin Islands and the Lesser Antilles. In this article, we attempt to characterize the 1867 earthquake with respect to fault orientation, rake, dip, fault dimensions, and first tsunami wave propagating phase, using tsunami simulations that employ high-resolution multibeam bathymetry. In addition, we present new geophysical and geological observations from the region of the suggested earthquake source. Results of our tsunami simulations based on relative amplitude comparison limit the earthquake source to be along the northern wall of the Virgin Islands basin, as suggested by Reid and Taber (1920), or on the carbonate platform north of the basin, and not in the Virgin Islands basin, as commonly assumed. The numerical simulations suggest the 1867 fault was striking 120°–135° and had a mixed normal and left-lateral motion. First propagating wave phase analysis suggests a fault striking 300°–315° is also possible. The best-fitting rupture length was found to be relatively small (50 km), probably indicating the earthquake had a moment magnitude of ∼7.2. Detailed multibeam echo sounder surveys of the Anegada Passage bathymetry between St. Croix and St. Thomas reveal a scarp, which cuts the northern wall of the Virgin Islands basin. High-resolution seismic profiles further indicate it to be a reasonable fault candidate. However, the fault orientation and the orientation of other subparallel faults in the area are more compatible with right-lateral motion. For the other possible source region, no clear disruption in the bathymetry or seismic profiles was found on the carbonate platform north of the basin.

  12. Recent tectonic stress field, active faults and geothermal fields (hot-water type) in China

    NASA Astrophysics Data System (ADS)

    Wan, Tianfeng

    1984-10-01

    It is quite probable that geothermal fields of the hot-water type in China do not develop in the absence of recently active faults. Such active faults are all controlled by tectonic stress fields. Using the data of earthquake fault-plane solutions, active faults, and surface thermal manifestations, a map showing the recent tectonic stress field, and the location of active faults and geothermal fields in China is presented. Data collected from 89 investigated prospects with geothermal manifestations indicate that the locations of geothermal fields are controlled by active faults and the recent tectonic stress field. About 68% of the prospects are controlled by tensional or tensional-shear faults. The angle between these faults and the direction of maximum compressive stress is less than 45°, and both tend to be parallel. About 15% of the prospects are controlled by conjugate faults. Another 14% are controlled by compressive-shear faults where the angle between these faults and the direction maximum compressive stress is greater than 45°.

  13. Multi-Fault Diagnosis of Rolling Bearings via Adaptive Projection Intrinsically Transformed Multivariate Empirical Mode Decomposition and High Order Singular Value Decomposition

    PubMed Central

    Lv, Yong; Song, Gangbing

    2018-01-01

    Rolling bearings are important components in rotary machinery systems. In the field of multi-fault diagnosis of rolling bearings, the vibration signal collected from single channels tends to miss some fault characteristic information. Using multiple sensors to collect signals at different locations on the machine to obtain multivariate signal can remedy this problem. The adverse effect of a power imbalance between the various channels is inevitable, and unfavorable for multivariate signal processing. As a useful, multivariate signal processing method, Adaptive-projection has intrinsically transformed multivariate empirical mode decomposition (APIT-MEMD), and exhibits better performance than MEMD by adopting adaptive projection strategy in order to alleviate power imbalances. The filter bank properties of APIT-MEMD are also adopted to enable more accurate and stable intrinsic mode functions (IMFs), and to ease mode mixing problems in multi-fault frequency extractions. By aligning IMF sets into a third order tensor, high order singular value decomposition (HOSVD) can be employed to estimate the fault number. The fault correlation factor (FCF) analysis is used to conduct correlation analysis, in order to determine effective IMFs; the characteristic frequencies of multi-faults can then be extracted. Numerical simulations and the application of multi-fault situation can demonstrate that the proposed method is promising in multi-fault diagnoses of multivariate rolling bearing signal. PMID:29659510

  14. 3D Dynamic Rupture Simulations along the Wasatch Fault, Utah, Incorporating Rough-fault Topography

    NASA Astrophysics Data System (ADS)

    Withers, Kyle; Moschetti, Morgan

    2017-04-01

    Studies have found that the Wasatch Fault has experienced successive large magnitude (>Mw 7.2) earthquakes, with an average recurrence interval near 350 years. To date, no large magnitude event has been recorded along the fault, with the last rupture along the Salt Lake City segment occurring 1300 years ago. Because of this, as well as the lack of strong ground motion records in basins and from normal-faulting earthquakes worldwide, seismic hazard in the region is not well constrained. Previous numerical simulations have modeled deterministic ground motion in the heavily populated regions of Utah, near Salt Lake City, but were primarily restricted to low frequencies ( 1 Hz). Our goal is to better assess broadband ground motions from the Wasatch Fault Zone. Here, we extend deterministic ground motion prediction to higher frequencies ( 5 Hz) in this region by using physics-based spontaneous dynamic rupture simulations along a normal fault with characteristics derived from geologic observations. We use a summation by parts finite difference code (Waveqlab3D) with rough-fault topography following a self-similar fractal distribution (over length scales from 100 m to the size of the fault) and include off-fault plasticity to simulate ruptures > Mw 6.5. Geometric complexity along fault planes has previously been shown to generate broadband sources with spectral energy matching that of observations. We investigate the impact of varying the hypocenter location, as well as the influence that multiple realizations of rough-fault topography have on the rupture process and resulting ground motion. We utilize Waveqlab3's computational efficiency to model wave-propagation to a significant distance from the fault with media heterogeneity at both long and short spatial wavelengths. These simulations generate a synthetic dataset of ground motions to compare with GMPEs, in terms of both the median and inter and intraevent variability.

  15. Dynamic earthquake rupture simulation on nonplanar faults embedded in 3D geometrically complex, heterogeneous Earth models

    NASA Astrophysics Data System (ADS)

    Duru, K.; Dunham, E. M.; Bydlon, S. A.; Radhakrishnan, H.

    2014-12-01

    Dynamic propagation of shear ruptures on a frictional interface is a useful idealization of a natural earthquake.The conditions relating slip rate and fault shear strength are often expressed as nonlinear friction laws.The corresponding initial boundary value problems are both numerically and computationally challenging.In addition, seismic waves generated by earthquake ruptures must be propagated, far away from fault zones, to seismic stations and remote areas.Therefore, reliable and efficient numerical simulations require both provably stable and high order accurate numerical methods.We present a numerical method for:a) enforcing nonlinear friction laws, in a consistent and provably stable manner, suitable for efficient explicit time integration;b) dynamic propagation of earthquake ruptures along rough faults; c) accurate propagation of seismic waves in heterogeneous media with free surface topography.We solve the first order form of the 3D elastic wave equation on a boundary-conforming curvilinear mesh, in terms of particle velocities and stresses that are collocated in space and time, using summation-by-parts finite differences in space. The finite difference stencils are 6th order accurate in the interior and 3rd order accurate close to the boundaries. Boundary and interface conditions are imposed weakly using penalties. By deriving semi-discrete energy estimates analogous to the continuous energy estimates we prove numerical stability. Time stepping is performed with a 4th order accurate explicit low storage Runge-Kutta scheme. We have performed extensive numerical experiments using a slip-weakening friction law on non-planar faults, including recent SCEC benchmark problems. We also show simulations on fractal faults revealing the complexity of rupture dynamics on rough faults. We are presently extending our method to rate-and-state friction laws and off-fault plasticity.

  16. Fethiye-Burdur Fault Zone (SW Turkey): a myth?

    NASA Astrophysics Data System (ADS)

    Kaymakci, Nuretdin; Langereis, Cornelis; Özkaptan, Murat; Özacar, Arda A.; Gülyüz, Erhan; Uzel, Bora; Sözbilir, Hasan

    2017-04-01

    Fethiye Burdur Fault Zone (FBFZ) is first proposed by Dumont et al. (1979) as a sinistral strike-slip fault zone as the NE continuation of Pliny-Strabo trench in to the Anatolian Block. The fault zone supposed to accommodate at least 100 km sinistral displacement between the Menderes Massif and the Beydaǧları platform during the exhumation of the Menderes Massif, mainly during the late Miocene. Based on GPS velocities Barka and Reilinger (1997) proposed that the fault zone is still active and accommodates sinistral displacement. In order to test the presence and to unravel its kinematics we have conducted a rigorous paleomagnetic study containing more than 3000 paleomagnetic samples collected from 88 locations and 11700 fault slip data collected from 198 locations distributed evenly all over SW Anatolia spanning from Middle Miocene to Late Pliocene. The obtained rotation senses and amounts indicate slight (around 20°) counter-clockwise rotations distributed uniformly almost whole SW Anatolia and there is no change in the rotation senses and amounts on either side of the FBFZ implying no differential rotation within the zone. Additionally, the slickenside pitches and constructed paleostress configurations, along the so called FBFZ and also within the 300 km diameter of the proposed fault zone, indicated that almost all the faults, oriented parallel to subparallel to the zone, are normal in character. The fault slip measurements are also consistent with earthquake focal mechanisms suggesting active extension in the region. We have not encountered any significant strike-slip motion in the region to support presence and transcurrent nature of the FBFZ. On the contrary, the region is dominated by extensional deformation and strike-slip components are observed only on the NW-SE striking faults which are transfer faults that accommodated extension and normal motion. Therefore, we claim that the sinistral Fethiye Burdur Fault (Zone) is a myth and there is no tangible

  17. Structural evolution of fault zones in sandstone by multiple deformation mechanisms: Moab fault, southeast Utah

    USGS Publications Warehouse

    Davatzes, N.C.; Eichhubl, P.; Aydin, A.

    2005-01-01

    Faults in sandstone are frequently composed of two classes of structures: (1) deformation bands and (2) joints and sheared joints. Whereas the former structures are associated with cataclastic deformation, the latter ones represent brittle fracturing, fragmentation, and brecciation. We investigated the distribution of these structures, their formation, and the underlying mechanical controls for their occurrence along the Moab normal fault in southeastern Utah through the use of structural mapping and numerical elastic boundary element modeling. We found that deformation bands occur everywhere along the fault, but with increased density in contractional relays. Joints and sheared joints only occur at intersections and extensional relays. In all locations , joints consistently overprint deformation bands. Localization of joints and sheared joints in extensional relays suggests that their distribution is controlled by local variations in stress state that are due to mechanical interaction between the fault segments. This interpretation is consistent with elastic boundary element models that predict a local reduction in mean stress and least compressive principal stress at intersections and extensional relays. The transition from deformation band to joint formation along these sections of the fault system likely resulted from the combined effects of changes in remote tectonic loading, burial depth, fluid pressure, and rock properties. In the case of the Moab fault, we conclude that the structural heterogeneity in the fault zone is systematically related to the geometric evolution of the fault, the local state of stress associated with fault slip , and the remote loading history. Because the type and distribution of structures affect fault permeability and strength, our results predict systematic variations in these parameters with fault evolution. ?? 2004 Geological Society of America.

  18. Fault growth and acoustic emissions in confined granite

    USGS Publications Warehouse

    Lockner, David A.; Byerlee, James D.

    1992-01-01

    The failure process in a brittle granite was studied by using acoustic emission techniques to obtain three dimensional locations of the microfracturing events. During a creep experiment the nucleation of faulting coincided with the onset of tertiary creep, but the development of the fault could not be followed because the failure occurred catastrophically. A technique has been developed that enables the failure process to be stabilized by controlling the axial stress to maintain a constant acoustic emission rate. As a result the post-failure stress-strain curve has been followed quasi-statically, extending to hours the fault growth process that normally would occur violently in a fraction of a second. The results from the rate-controlled experiments show that the fault plane nucleated at a point on the sample surface after the stress-strain curve reached its peak. Before nucleation, the microcrack growth was distributed throughout the sample. The fault plane then grew outward from the nucleation site and was accompanied by a gradual drop in stress. Acoustic emission locations showed that the fault propagated as a fracture front (process zone) with dimensions of 1 to 3 cm. As the fracture front passed by a given fixed point on the fault plane, the subsequent acoustic emission would drop. When growth was allowed to progress until the fault bisected the sample, the stress dropped to the frictional strength. These observations are in accord with the behavior predicted by Rudnicki and Rice's bifurcation analysis but conflict with experiments used to infer that shear localization would occur in brittle rock while the material is still hardening.

  19. Slip-parallel seismic lineations on the Northern Hayward Fault, California

    USGS Publications Warehouse

    Waldhauser, F.; Ellsworth, W.L.; Cole, A.

    1999-01-01

    A high-resolution relative earthquake location procedure is used to image the fine-scale seismicity structure of the northern Hayward fault, California. The seismicity defines a narrow, near-vertical fault zone containing horizontal alignments of hypocenters extending along the fault zone. The lineations persist over the 15-year observation interval, implying the localization of conditions on the fault where brittle failure conditions are met. The horizontal orientation of the lineations parallels the slip direction of the fault, suggesting that they are the result of the smearing of frictionally weak material along the fault plane over thousands of years.

  20. Towards "realistic" fault zones in a 3D structure model of the Thuringian Basin, Germany

    NASA Astrophysics Data System (ADS)

    Kley, J.; Malz, A.; Donndorf, S.; Fischer, T.; Zehner, B.

    2012-04-01

    3D computer models of geological architecture are evolving into a standard tool for visualization and analysis. Such models typically comprise the bounding surfaces of stratigraphic layers and faults. Faults affect the continuity of aquifers and can themselves act as fluid conduits or barriers. This is one reason why a "realistic" representation of faults in 3D models is desirable. Still so, many existing models treat faults in a simplistic fashion, e.g. as vertical downward projections of fault traces observed at the surface. Besides being geologically and mechanically unreasonable, this also causes technical difficulties in the modelling workflow. Most natural faults are inclined and may change dips according to rock type or flatten into mechanically weak layers. Boreholes located close to a fault can therefore cross it at depth, resulting in stratigraphic control points allocated to the wrong block. Also, faults tend to split up into several branches, forming fault zones. Obtaining a more accurate representation of faults and fault zones is therefore challenging. We present work-in-progress from the Thuringian Basin in central Germany. The fault zone geometries are never fully constrained by data and must be extrapolated to depth. We use balancing of serial, parallel cross-sections to constrain subsurface extrapolations. The structure sections are checked for consistency by restoring them to an undeformed state. If this is possible without producing gaps or overlaps, the interpretation is considered valid (but not unique) for a single cross-section. Additional constraints are provided by comparison of adjacent cross-sections. Structures should change continuously from one section to another. Also, from the deformed and restored cross-sections we can measure the strain incurred during deformation. Strain should be compatible among the cross-sections: If at all, it should vary smoothly and systematically along a given fault zone. The stratigraphic contacts and

  1. Identifying Conventionally Sub-Seismic Faults in Polygonal Fault Systems

    NASA Astrophysics Data System (ADS)

    Fry, C.; Dix, J.

    2017-12-01

    Polygonal Fault Systems (PFS) are prevalent in hydrocarbon basins globally and represent potential fluid pathways. However the characterization of these pathways is subject to the limitations of conventional 3D seismic imaging; only capable of resolving features on a decametre scale horizontally and metres scale vertically. While outcrop and core examples can identify smaller features, they are limited by the extent of the exposures. The disparity between these scales can allow for smaller faults to be lost in a resolution gap which could mean potential pathways are left unseen. Here the focus is upon PFS from within the London Clay, a common bedrock that is tunnelled into and bears construction foundations for much of London. It is a continuation of the Ieper Clay where PFS were first identified and is found to approach the seafloor within the Outer Thames Estuary. This allows for the direct analysis of PFS surface expressions, via the use of high resolution 1m bathymetric imaging in combination with high resolution seismic imaging. Through use of these datasets surface expressions of over 1500 faults within the London Clay have been identified, with the smallest fault measuring 12m and the largest at 612m in length. The displacements over these faults established from both bathymetric and seismic imaging ranges from 30cm to a couple of metres, scales that would typically be sub-seismic for conventional basin seismic imaging. The orientations and dimensions of the faults within this network have been directly compared to 3D seismic data of the Ieper Clay from the offshore Dutch sector where it exists approximately 1km below the seafloor. These have typical PFS attributes with lengths of hundreds of metres to kilometres and throws of tens of metres, a magnitude larger than those identified in the Outer Thames Estuary. The similar orientations and polygonal patterns within both locations indicates that the smaller faults exist within typical PFS structure but are

  2. Fault Analysis of Space Station DC Power Systems-Using Neural Network Adaptive Wavelets to Detect Faults

    NASA Technical Reports Server (NTRS)

    Momoh, James A.; Wang, Yanchun; Dolce, James L.

    1997-01-01

    This paper describes the application of neural network adaptive wavelets for fault diagnosis of space station power system. The method combines wavelet transform with neural network by incorporating daughter wavelets into weights. Therefore, the wavelet transform and neural network training procedure become one stage, which avoids the complex computation of wavelet parameters and makes the procedure more straightforward. The simulation results show that the proposed method is very efficient for the identification of fault locations.

  3. Accurate relative location estimates for the North Korean nuclear tests using empirical slowness corrections

    NASA Astrophysics Data System (ADS)

    Gibbons, S. J.; Pabian, F.; Näsholm, S. P.; Kværna, T.; Mykkeltveit, S.

    2017-01-01

    velocity gradients reduce the residuals, the relative location uncertainties and the sensitivity to the combination of stations used. The traveltime gradients appear to be overestimated for the regional phases, and teleseismic relative location estimates are likely to be more accurate despite an apparent lower precision. Calibrations for regional phases are essential given that smaller magnitude events are likely not to be recorded teleseismically. We discuss the implications for the absolute event locations. Placing the 2006 event under a local maximum of overburden at 41.293°N, 129.105°E would imply a location of 41.299°N, 129.075°E for the January 2016 event, providing almost optimal overburden for the later four events.

  4. The relationship of near-surface active faulting to megathrust splay fault geometry in Prince William Sound, Alaska

    NASA Astrophysics Data System (ADS)

    Finn, S.; Liberty, L. M.; Haeussler, P. J.; Northrup, C.; Pratt, T. L.

    2010-12-01

    We interpret regionally extensive, active faults beneath Prince William Sound (PWS), Alaska, to be structurally linked to deeper megathrust splay faults, such as the one that ruptured in the 1964 M9.2 earthquake. Western PWS in particular is unique; the locations of active faulting offer insights into the transition at the southern terminus of the previously subducted Yakutat slab to Pacific plate subduction. Newly acquired high-resolution, marine seismic data show three seismic facies related to Holocene and older Quaternary to Tertiary strata. These sediments are cut by numerous high angle normal faults in the hanging wall of megathrust splay. Crustal-scale seismic reflection profiles show splay faults emerging from 20 km depth between the Yakutat block and North American crust and surfacing as the Hanning Bay and Patton Bay faults. A distinct boundary coinciding beneath the Hinchinbrook Entrance causes a systematic fault trend change from N30E in southwestern PWS to N70E in northeastern PWS. The fault trend change underneath Hinchinbrook Entrance may occur gradually or abruptly and there is evidence for similar deformation near the Montague Strait Entrance. Landward of surface expressions of the splay fault, we observe subsidence, faulting, and landslides that record deformation associated with the 1964 and older megathrust earthquakes. Surface exposures of Tertiary rocks throughout PWS along with new apatite-helium dates suggest long-term and regional uplift with localized, fault-controlled subsidence.

  5. Strike-slip fault propagation and linkage via work optimization with application to the San Jacinto fault, California

    NASA Astrophysics Data System (ADS)

    Madden, E. H.; McBeck, J.; Cooke, M. L.

    2013-12-01

    Over multiple earthquake cycles, strike-slip faults link to form through-going structures, as demonstrated by the continuous nature of the mature San Andreas fault system in California relative to the younger and more segmented San Jacinto fault system nearby. Despite its immaturity, the San Jacinto system accommodates between one third and one half of the slip along the boundary between the North American and Pacific plates. It therefore poses a significant seismic threat to southern California. Better understanding of how the San Jacinto system has evolved over geologic time and of current interactions between faults within the system is critical to assessing this seismic hazard accurately. Numerical models are well suited to simulating kilometer-scale processes, but models of fault system development are challenged by the multiple physical mechanisms involved. For example, laboratory experiments on brittle materials show that faults propagate and eventually join (hard-linkage) by both opening-mode and shear failure. In addition, faults interact prior to linkage through stress transfer (soft-linkage). The new algorithm GROW (GRowth by Optimization of Work) accounts for this complex array of behaviors by taking a global approach to fault propagation while adhering to the principals of linear elastic fracture mechanics. This makes GROW a powerful tool for studying fault interactions and fault system development over geologic time. In GROW, faults evolve to minimize the work (or energy) expended during deformation, thereby maximizing the mechanical efficiency of the entire system. Furthermore, the incorporation of both static and dynamic friction allows GROW models to capture fault slip and fault propagation in single earthquakes as well as over consecutive earthquake cycles. GROW models with idealized faults reveal that the initial fault spacing and the applied stress orientation control fault linkage propensity and linkage patterns. These models allow the gains in

  6. Artificial neural network application for space station power system fault diagnosis

    NASA Technical Reports Server (NTRS)

    Momoh, James A.; Oliver, Walter E.; Dias, Lakshman G.

    1995-01-01

    This study presents a methodology for fault diagnosis using a Two-Stage Artificial Neural Network Clustering Algorithm. Previously, SPICE models of a 5-bus DC power distribution system with assumed constant output power during contingencies from the DDCU were used to evaluate the ANN's fault diagnosis capabilities. This on-going study uses EMTP models of the components (distribution lines, SPDU, TPDU, loads) and power sources (DDCU) of Space Station Alpha's electrical Power Distribution System as a basis for the ANN fault diagnostic tool. The results from the two studies are contrasted. In the event of a major fault, ground controllers need the ability to identify the type of fault, isolate the fault to the orbital replaceable unit level and provide the necessary information for the power management expert system to optimally determine a degraded-mode load schedule. To accomplish these goals, the electrical power distribution system's architecture can be subdivided into three major classes: DC-DC converter to loads, DC Switching Unit (DCSU) to Main bus Switching Unit (MBSU), and Power Sources to DCSU. Each class which has its own electrical characteristics and operations, requires a unique fault analysis philosophy. This study identifies these philosophies as Riddles 1, 2 and 3 respectively. The results of the on-going study addresses Riddle-1. It is concluded in this study that the combination of the EMTP models of the DDCU, distribution cables and electrical loads yields a more accurate model of the behavior and in addition yielded more accurate fault diagnosis using ANN versus the results obtained with the SPICE models.

  7. Fast and accurate spectral estimation for online detection of partial broken bar in induction motors

    NASA Astrophysics Data System (ADS)

    Samanta, Anik Kumar; Naha, Arunava; Routray, Aurobinda; Deb, Alok Kanti

    2018-01-01

    In this paper, an online and real-time system is presented for detecting partial broken rotor bar (BRB) of inverter-fed squirrel cage induction motors under light load condition. This system with minor modifications can detect any fault that affects the stator current. A fast and accurate spectral estimator based on the theory of Rayleigh quotient is proposed for detecting the spectral signature of BRB. The proposed spectral estimator can precisely determine the relative amplitude of fault sidebands and has low complexity compared to available high-resolution subspace-based spectral estimators. Detection of low-amplitude fault components has been improved by removing the high-amplitude fundamental frequency using an extended-Kalman based signal conditioner. Slip is estimated from the stator current spectrum for accurate localization of the fault component. Complexity and cost of sensors are minimal as only a single-phase stator current is required. The hardware implementation has been carried out on an Intel i7 based embedded target ported through the Simulink Real-Time. Evaluation of threshold and detectability of faults with different conditions of load and fault severity are carried out with empirical cumulative distribution function.

  8. Map and Data for Quaternary Faults and Fault Systems on the Island of Hawai`i

    USGS Publications Warehouse

    Cannon, Eric C.; Burgmann, Roland; Crone, Anthony J.; Machette, Michael N.; Dart, Richard L.

    2007-01-01

    Introduction This report and digitally prepared, GIS-based map is one of a series of similar products covering individual states or regions of United States that show the locations, ages, and activity rates of major earthquake-related features such as faults and fault-related folds. It is part of a continuing the effort to compile a comprehensive Quaternary fault and fold map and database for the United States, which is supported by the U.S. Geological Survey's (USGS) Earthquake Hazards Program. Guidelines for the compilation of the Quaternary fault and fold maps for the United States were published by Haller and others (1993) at the onset of this project. This compilation of Quaternary surface faulting and folding in Hawai`i is one of several similar state and regional compilations that were planned for the United States. Reports published to date include West Texas (Collins and others, 1996), New Mexico (Machette and others, 1998), Arizona (Pearthree, 1998), Colorado (Widmann and others, 1998), Montana (Stickney and others, 2000), Idaho (Haller and others, 2005), and Washington (Lidke and others, 2003). Reports for other states such as California and Alaska are still in preparation. The primary intention of this compilation is to aid in seismic-hazard evaluations. The report contains detailed information on the location and style of faulting, the time of most recent movement, and assigns each feature to a slip-rate category (as a proxy for fault activity). It also contains the name and affiliation of the compiler, date of compilation, geographic and other paleoseismologic parameters, as well as an extensive set of references for each feature. The map (plate 1) shows faults, volcanic rift zones, and lineaments that show evidence of Quaternary surface movement related to faulting, including data on the time of most recent movement, sense of movement, slip rate, and continuity of surface expression. This compilation is presented as a digitally prepared map product

  9. Lembang fault plane identification using electrical resistivity method for disaster mitigation

    NASA Astrophysics Data System (ADS)

    Maulinadya, S.; Ramadhan, M. Lutfi; N. Wening, F.; Pinehas, D.; Widodo

    2017-07-01

    Lembang Fault is an active fault lies from West to East located 10 kilometers in north of Bandung. It is a normal fault that its foot wall raises 40-450 meters above the ground. Its location that is not so far from Bandung, which is densely populated and frequently visited by tourists, makes Lembang Fault a threat if it becomes suddenly active. Its movement can cause earthquakes that can result in fatalities. Therefore, act of mitigation is necessary, such as educating people about Lembang Fault and its potential to cause disaster. The objective of this study is to find Lembang Fault plane below the surface with geo electrical mapping method and vertical elect rical sounding method around Ciwarega and The Peak, Lembang (west side of Lembang Fault). Both of these methods are using electricity current to measure rock resistivity. Currents are injected to the ground and potential differences are measured. According to Ohm's Law, resistivity can be calculated so that resistivity distribution can be obtained. In this study, high resistivity contrast is obtained; it is about 1400-5000 Ohm.m. This resistivity contrast can be caused by lateral lithology difference resulted by fault existence. This proves that there is actually a fault in Lembang that potentially cause disasters like earthquakes.

  10. Tectono-stratigraphic evolution of normal fault zones: Thal Fault Zone, Suez Rift, Egypt

    NASA Astrophysics Data System (ADS)

    Leppard, Christopher William

    propagation and early linkage of the precursor fault strands at depth before the fault segment broke surface, followed by the accumulation of displacement on the linked fault segment with minimal lateral propagation. This style of fault growth contrasts conventional fault growth models by which growth occurs through incremental increases in both displacement and length through time. The evolution of normal fault populations and fault zones exerts a first- order control on basin physiography and sediment supply, and therefore, the architecture and distribution of coeval syn-rift stratigraphy. The early syn-rift continental, Abu Zenima Formation, to shallow marine, Nukhul Formation show a pronounced westward increase in thickness controlled by the series of synthetic and antithetic faults up to 3 km west of present day Thai fault. The orientation of these faults controlled the location of fluvial conglomerates, sandstones and mudstones that shifted to the topographic lows created. The progressive localisation of displacement onto the Sarbut El Gamal fault segment during rift-climax resulted in an overall change in basin geometry. Accelerated subsidence rates led to sedimentation rates being outpaced by subsidence resulting in the development of a marine, sediment-starved, underfilled hangingwall depocentre characterised by slope-to-basinal depositional environments, with a laterally continuous slope apron in the immediate hangingwall, and point-sourced submarine fans. Controls on the spatial distribution, three dimensional architecture, and facies stacking patterns of coeval syn-rift deposits are identified as: I) structural style of the evolution and linkage of normal fault populations, ii) basin physiography, iii) evolution of drainage catchments, iv) bedrock lithology, and v) variations in sea/lake level.

  11. Apparatus including a plurality of spaced transformers for locating short circuits in cables

    NASA Technical Reports Server (NTRS)

    Cason, R. L.; Mcstay, J. J. (Inventor)

    1978-01-01

    A cable fault locator is described for sensing faults such as short circuits in power cables. The apparatus includes a plurality of current transformers strategically located along a cable. Trigger circuits are connected to each of the current transformers for placing a resistor in series with a resistive element responsive to an abnormally high current flowing through that portion of the cable. By measuring the voltage drop across the resistive element, the location of the fault can be determined.

  12. Relationship between displacement and gravity change of Uemachi faults and surrounding faults of Osaka basin, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Inoue, N.; Kitada, N.; Kusumoto, S.; Itoh, Y.; Takemura, K.

    2011-12-01

    The Osaka basin surrounded by the Rokko and Ikoma Ranges is one of the typical Quaternary sedimentary basins in Japan. The Osaka basin has been filled by the Pleistocene Osaka group and the later sediments. Several large cities and metropolitan areas, such as Osaka and Kobe are located in the Osaka basin. The basin is surrounded by E-W trending strike slip faults and N-S trending reverse faults. The N-S trending 42-km-long Uemachi faults traverse in the central part of the Osaka city. The Uemachi faults have been investigated for countermeasures against earthquake disaster. It is important to reveal the detailed fault parameters, such as length, dip and recurrence interval, so on for strong ground motion simulation and disaster prevention. For strong ground motion simulation, the fault model of the Uemachi faults consist of the two parts, the north and south parts, because of the no basement displacement in the central part of the faults. The Ministry of Education, Culture, Sports, Science and Technology started the project to survey of the Uemachi faults. The Disaster Prevention Institute of Kyoto University is carried out various surveys from 2009 to 2012 for 3 years. The result of the last year revealed the higher fault activity of the branch fault than main faults in the central part (see poster of "Subsurface Flexure of Uemachi Fault, Japan" by Kitada et al., in this meeting). Kusumoto et al. (2001) reported that surrounding faults enable to form the similar basement relief without the Uemachi faults model based on a dislocation model. We performed various parameter studies for dislocation model and gravity changes based on simplified faults model, which were designed based on the distribution of the real faults. The model was consisted 7 faults including the Uemachi faults. The dislocation and gravity change were calculated based on the Okada et al. (1985) and Okubo et al. (1993) respectively. The results show the similar basement displacement pattern to the

  13. Fault-zone guided waves from explosions in the San Andreas fault at Parkfield and Cienega Valley, California

    USGS Publications Warehouse

    Li, Y.-G.; Ellsworth, W.L.; Thurber, C.H.; Malin, P.E.; Aki, K.

    1997-01-01

    Fault-zone guided waves were successfully excited by near-surface explosions in the San Andreas fault zone both at Parkfield and Cienega Valley, central California. The guided waves were observed on linear, three-component seismic arrays deployed across the fault trace. These waves were not excited by explosions located outside the fault zone. The amplitude spectra of guided waves show a maximum peak at 2 Hz at Parkfield and 3 Hz at Cienega Valley. The guided wave amplitude decays sharply with observation distance from the fault trace. The explosion-excited fault-zone guided waves are similar to those generated by earthquakes at Parkfield but have lower frequencies and travel more slowly. These observations suggest that the fault-zone wave guide has lower seismic velocities as it approaches the surface at Parkfield. We have modeled the waveforms as S waves trapped in a low-velocity wave guide sandwiched between high-velocity wall rocks, resulting in Love-type fault-zone guided waves. While the results are nonunique, the Parkfield data are adequately fit by a shallow wave guide 170 m wide with an S velocity 0.85 km/sec and an apparent Q ??? 30 to 40. At Cienega Valley, the fault-zone wave guide appears to be about 120 m wide with an S velocity 0.7 km/sec and a Q ??? 30.

  14. Stresses, deformation, and seismic events on scaled experimental faults with heterogeneous fault segments and comparison to numerical modeling

    NASA Astrophysics Data System (ADS)

    Buijze, Loes; Guo, Yanhuang; Niemeijer, André R.; Ma, Shengli; Spiers, Christopher J.

    2017-04-01

    Faults in the upper crust cross-cut many different lithologies, which cause the composition of the fault rocks to vary. Each different fault rock segment may have specific mechanical properties, e.g. there may be stronger and weaker segments, and segments prone to unstable slip or creeping. This leads to heterogeneous deformation and stresses along such faults, and a heterogeneous distribution of seismic events. We address the influence of fault variability on stress, deformation, and seismicity using a combination of scaled laboratory fault and numerical modeling. A vertical fault was created along the diagonal of a 30 x 20 x 5 cm block of PMMA, along which a 2 mm thick gouge layer was deposited. Gouge materials of different characteristics were used to create various segments along the fault; quartz (average strength, stable sliding), kaolinite (weak, stable sliding), and gypsum (average strength, unstable sliding). The sample assembly was placed in a horizontal biaxial deformation apparatus, and shear displacement was enforced along the vertical fault. Multiple observations were made: 1) Acoustic emissions were continuously recorded at 3 MHz to observe the occurrence of stick-slips (micro-seismicity), 2) Photo-elastic effects (indicative of the differential stress) were recorded in the transparent set of PMMA wall-rocks using a high-speed camera, and 3) particle tracking was conducted on a speckle painted set of PMMA wall-rocks to study the deformation in the wall-rocks flanking the fault. All three observation methods show how the heterogeneous fault gouge exerts a strong control on the fault behavior. For example, a strong, unstable segment of gypsum flanked by two weaker kaolinite segments show strong stress concentrations develop near the edges of the strong segment, with at the same time most of acoustic emissions being located at the edge of this strong segment. The measurements of differential stress, strain and acoustic emissions provide a strong means

  15. A wideband magnetoresistive sensor for monitoring dynamic fault slip in laboratory fault friction experiments

    USGS Publications Warehouse

    Kilgore, Brian D.

    2017-01-01

    A non-contact, wideband method of sensing dynamic fault slip in laboratory geophysical experiments employs an inexpensive magnetoresistive sensor, a small neodymium rare earth magnet, and user built application-specific wideband signal conditioning. The magnetoresistive sensor generates a voltage proportional to the changing angles of magnetic flux lines, generated by differential motion or rotation of the near-by magnet, through the sensor. The performance of an array of these sensors compares favorably to other conventional position sensing methods employed at multiple locations along a 2 m long × 0.4 m deep laboratory strike-slip fault. For these magnetoresistive sensors, the lack of resonance signals commonly encountered with cantilever-type position sensor mounting, the wide band response (DC to ≈ 100 kHz) that exceeds the capabilities of many traditional position sensors, and the small space required on the sample, make them attractive options for capturing high speed fault slip measurements in these laboratory experiments. An unanticipated observation of this study is the apparent sensitivity of this sensor to high frequency electomagnetic signals associated with fault rupture and (or) rupture propagation, which may offer new insights into the physics of earthquake faulting.

  16. Recently active traces of the Bartlett Springs Fault, California: a digital database

    USGS Publications Warehouse

    Lienkaemper, James J.

    2010-01-01

    The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Bartlett Springs Fault Zone, California. The location and recency of the mapped traces is primarily based on geomorphic expression of the fault as interpreted from large-scale aerial photography. In a few places, evidence of fault creep and offset Holocene strata in trenches and natural exposures have confirmed the activity of some of these traces. This publication is formatted both as a digital database for use within a geographic information system (GIS) and for broader public access as map images that may be browsed on-line or download a summary map. The report text describes the types of scientific observations used to make the map, gives references pertaining to the fault and the evidence of faulting, and provides guidance for use of and limitations of the map.

  17. Relating Seismicity to Dike Emplacement, and the Conundrum of Dyke-Parallel Faulting

    NASA Astrophysics Data System (ADS)

    Dering, G.; Micklethwaite, S.; Cruden, A. R.; Barnes, S. J.; Fiorentini, M. L.

    2016-12-01

    Seismic monitoring shows that faulting and fracturing precede and accompany magma emplacement on timescales of hours and days. One outstanding problem is that the precision of earthquake hypocentre locations is typically limited to tens or hundreds of meters and cannot resolve whether the hypocentres relate to strain of wall rock fragments within the dikes, in a process zone around the intrusion or peripherally in the country rock. We examine a swarm of 19 dolerite dikes, near Albany, Western Australia using an unmanned aerial vehicle and Structure-from-Motion photogrammetry to obtain accurate, high resolution 3D reconstructions of outcrop and to digitally extract structural data. We find rare overprinting relationships indicate dike emplacement and faulting was coeval and that the number of faults/fractures increase into the dike swarm (2.2 ± 0.7 more fractures, per unit length in host rocks intruded by dikes relative to the background value). The faults are cataclasite-bearing and parallel to the dikes but intriguingly dike emplacement appears to have been accommodated by mode 1 extension. We further provide the first evidence that dike-parallel shear failure occurs in a damage zone associated with the dike swarm. These results support seismological observations of dike-parallel shear failure associated with some intrusion events, which contradict Mohr-Coulomb theory and numerical modelling of dike propagation in brittle-elastic rock, where shear failure is predicted to occur on faults oriented approximately 30° to the dyke plane. We suggest the dike swarm occupies a network of joints and fractures formed prior to swarm emplacement but then reactivated ahead of propagating dikes and remaining active during the early stages of emplacement.

  18. Single-phase power distribution system power flow and fault analysis

    NASA Technical Reports Server (NTRS)

    Halpin, S. M.; Grigsby, L. L.

    1992-01-01

    Alternative methods for power flow and fault analysis of single-phase distribution systems are presented. The algorithms for both power flow and fault analysis utilize a generalized approach to network modeling. The generalized admittance matrix, formed using elements of linear graph theory, is an accurate network model for all possible single-phase network configurations. Unlike the standard nodal admittance matrix formulation algorithms, the generalized approach uses generalized component models for the transmission line and transformer. The standard assumption of a common node voltage reference point is not required to construct the generalized admittance matrix. Therefore, truly accurate simulation results can be obtained for networks that cannot be modeled using traditional techniques.

  19. CO2 Push-Pull Single Fault Injection Simulations

    DOE Data Explorer

    Borgia, Andrea; Oldenburg, Curtis (ORCID:0000000201326016); Zhang, Rui; Pan, Lehua; Daley, Thomas M.; Finsterle, Stefan; Ramakrishnan, T.S.; Doughty, Christine; Jung, Yoojin; Lee, Kyung Jae; Altundas, Bilgin; Chugunov, Nikita

    2017-09-21

    ASCII text files containing grid-block name, X-Y-Z location, and multiple parameters from TOUGH2 simulation output of CO2 injection into an idealized single fault representing a dipping normal fault at the Desert Peak geothermal field (readable by GMS). The fault is composed of a damage zone, a fault gouge and a slip plane. The runs are described in detail in the following: Borgia A., Oldenburg C.M., Zhang R., Jung Y., Lee K.J., Doughty C., Daley T.M., Chugunov N., Altundas B, Ramakrishnan T.S., 2017. Carbon Dioxide Injection for Enhanced Characterization of Faults and Fractures in Geothermal Systems. Proceedings of the 42st Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California, February 13-17.

  20. FaultLab: Results on the crustal structure of the North Anatolian Fault from a dense seismic network

    NASA Astrophysics Data System (ADS)

    Thompson, David; Rost, Sebastian; Houseman, Greg; Cornwell, David; Türkelli, Niyazi; Uǧur, Teoman, Kahraman, Metin; Altuncu Poyraz, Selda; Gülen, Levent; Utkucu, Murat; Frederiksen, Andrew

    2013-04-01

    The North Anatolian Fault Zone (NAFZ) is a major continental strike-slip fault system, similar in size and scale to the San Andreas system, that extends ~1200 km across Turkey from the Aegean coast on the west to the Lake Van region in the east. FaultLab is a multidisciplinary project that aims to better understand deformation throughout the entire crust in the NAFZ, in particular the expected transition from narrow zones of brittle deformation in the upper crust to broad shear zones in the lower crust/upper mantle and how these features contribute to the earthquake loading cycle. The project incorporates broadband seismology, satellite geodesy, structural geology and numerical modelling in order to give an unprecedented view of the dynamic state of the NAFZ in the vicinity of the devastating 1999 Izmit and Düzce earthquakes. This contribution will discuss the first results from the seismic component of the project, a 73 station network encompassing the northern and southern branches of the NAFZ in the Sakarya region. Deployed in May 2012, the Dense Array for North Anatolia (DANA) is arranged as a 6×11 grid with a nominal station spacing of 7 km, with a further 7 stations located outside of the grid. Receiver function analysis will provide estimates of bulk crustal properties, along with information regarding heterogeneity at depth (dipping interfaces/anisotropy). With the excellent resolution afforded by the DANA network, we will present results using the technique of teleseismic scattering tomography. The method uses a full waveform inversion of teleseismic signals coupled with array processing techniques to infer the properties and location of small-scale heterogeneities (with scales on the order of the seismic wavelength) within the crust. Images obtained using these methods will provide evidence for how the deformation is distributed within the fault zone at depth, providing constraints that can be used in conjunction with structural analyses of exhumed

  1. Fault latency in the memory - An experimental study on VAX 11/780

    NASA Technical Reports Server (NTRS)

    Chillarege, Ram; Iyer, Ravishankar K.

    1986-01-01

    Fault latency is the time between the physical occurrence of a fault and its corruption of data, causing an error. The measure of this time is difficult to obtain because the time of occurrence of a fault and the exact moment of generation of an error are not known. This paper describes an experiment to accurately study the fault latency in the memory subsystem. The experiment employs real memory data from a VAX 11/780 at the University of Illinois. Fault latency distributions are generated for s-a-0 and s-a-1 permanent fault models. Results show that the mean fault latency of a s-a-0 fault is nearly 5 times that of the s-a-1 fault. Large variations in fault latency are found for different regions in memory. An analysis of a variance model to quantify the relative influence of various workload measures on the evaluated latency is also given.

  2. A novel method for intelligent fault diagnosis of rolling bearings using ensemble deep auto-encoders

    NASA Astrophysics Data System (ADS)

    Shao, Haidong; Jiang, Hongkai; Lin, Ying; Li, Xingqiu

    2018-03-01

    Automatic and accurate identification of rolling bearings fault categories, especially for the fault severities and fault orientations, is still a major challenge in rotating machinery fault diagnosis. In this paper, a novel method called ensemble deep auto-encoders (EDAEs) is proposed for intelligent fault diagnosis of rolling bearings. Firstly, different activation functions are employed as the hidden functions to design a series of auto-encoders (AEs) with different characteristics. Secondly, EDAEs are constructed with various auto-encoders for unsupervised feature learning from the measured vibration signals. Finally, a combination strategy is designed to ensure accurate and stable diagnosis results. The proposed method is applied to analyze the experimental bearing vibration signals. The results confirm that the proposed method can get rid of the dependence on manual feature extraction and overcome the limitations of individual deep learning models, which is more effective than the existing intelligent diagnosis methods.

  3. Trust index based fault tolerant multiple event localization algorithm for WSNs.

    PubMed

    Xu, Xianghua; Gao, Xueyong; Wan, Jian; Xiong, Naixue

    2011-01-01

    This paper investigates the use of wireless sensor networks for multiple event source localization using binary information from the sensor nodes. The events could continually emit signals whose strength is attenuated inversely proportional to the distance from the source. In this context, faults occur due to various reasons and are manifested when a node reports a wrong decision. In order to reduce the impact of node faults on the accuracy of multiple event localization, we introduce a trust index model to evaluate the fidelity of information which the nodes report and use in the event detection process, and propose the Trust Index based Subtract on Negative Add on Positive (TISNAP) localization algorithm, which reduces the impact of faulty nodes on the event localization by decreasing their trust index, to improve the accuracy of event localization and performance of fault tolerance for multiple event source localization. The algorithm includes three phases: first, the sink identifies the cluster nodes to determine the number of events occurred in the entire region by analyzing the binary data reported by all nodes; then, it constructs the likelihood matrix related to the cluster nodes and estimates the location of all events according to the alarmed status and trust index of the nodes around the cluster nodes. Finally, the sink updates the trust index of all nodes according to the fidelity of their information in the previous reporting cycle. The algorithm improves the accuracy of localization and performance of fault tolerance in multiple event source localization. The experiment results show that when the probability of node fault is close to 50%, the algorithm can still accurately determine the number of the events and have better accuracy of localization compared with other algorithms.

  4. Trust Index Based Fault Tolerant Multiple Event Localization Algorithm for WSNs

    PubMed Central

    Xu, Xianghua; Gao, Xueyong; Wan, Jian; Xiong, Naixue

    2011-01-01

    This paper investigates the use of wireless sensor networks for multiple event source localization using binary information from the sensor nodes. The events could continually emit signals whose strength is attenuated inversely proportional to the distance from the source. In this context, faults occur due to various reasons and are manifested when a node reports a wrong decision. In order to reduce the impact of node faults on the accuracy of multiple event localization, we introduce a trust index model to evaluate the fidelity of information which the nodes report and use in the event detection process, and propose the Trust Index based Subtract on Negative Add on Positive (TISNAP) localization algorithm, which reduces the impact of faulty nodes on the event localization by decreasing their trust index, to improve the accuracy of event localization and performance of fault tolerance for multiple event source localization. The algorithm includes three phases: first, the sink identifies the cluster nodes to determine the number of events occurred in the entire region by analyzing the binary data reported by all nodes; then, it constructs the likelihood matrix related to the cluster nodes and estimates the location of all events according to the alarmed status and trust index of the nodes around the cluster nodes. Finally, the sink updates the trust index of all nodes according to the fidelity of their information in the previous reporting cycle. The algorithm improves the accuracy of localization and performance of fault tolerance in multiple event source localization. The experiment results show that when the probability of node fault is close to 50%, the algorithm can still accurately determine the number of the events and have better accuracy of localization compared with other algorithms. PMID:22163972

  5. 3D resistivity survey for shallow subsurface fault investigations

    NASA Astrophysics Data System (ADS)

    Petrit, Kraipat; Klamthim, Poonnapa; Duerrast, Helmut

    2018-03-01

    The shallow subsurface is subject to various human activities, and the place of occurrence of geohazards, e.g. shallow active faults. The identification of the location and orientation of such faults can be vital for infrastructure development. The aim of this study was to develop a low-cost 3D resistivity survey system, with reasonable survey time for shallow fault investigations. The study area in Songkhla Province, Thailand is located in an old quarry where faults could be identified in outcrops. The study area was designed to cover the expected fault with 100 electrodes arranged in a 10×10 square grid with an electrode spacing of 3 meters in x and y axis. Each electrode in turn was used as a current and potential electrode using a dipole-dipole array. Field data have been processed and interpreted using 3DResINV. Results, presented in horizontal depth slices and vertical xz- and yz-cross sections, revealed through differences in resistivity down to 8 m depths a complex structural setting with two shallow faults and dipping sedimentary rock layers. In conclusion, this study has shown that a 3D resistivity survey can imagine complex tectonic structures, thus providing a far more insight into the shallow subsurface.

  6. Current microseismicity and generating faults in the Gyeongju area, southeastern Korea

    NASA Astrophysics Data System (ADS)

    Han, Minhui; Kim, Kwang-Hee; Son, Moon; Kang, Su Young

    2017-01-01

    A study of microseismicity in a 15 × 20 km2 subregion of Gyeongju, southeastern Korea, establishes a direct link between minor earthquakes and known fault structures. The study area has a complex history of tectonic deformation and has experienced large historic earthquakes, with small earthquakes recorded since the beginning of modern instrumental monitoring. From 5 years of continuously recorded local seismic data, 311 previously unidentified microearthquakes can be reliably located using the double-difference algorithm. These newly discovered events occur in linear streaks that can be spatially correlated with active faults, which could pose a serious hazard to nearby communities. At-risk infrastructure includes the largest industrial park in South Korea, nuclear power plants, and disposal facilities for radioactive waste. The current work suggests that the southern segment of the Yeonil Tectonic Line and segments of the Seokup and Waup Basin boundary faults are active. For areas with high rates of microseismic activity, reliably located hypocenters are spatially correlated with mapped faults; in less active areas, earthquake clusters tend to occur at fault intersections. Microearthquakes in stable continental regions are known to exist, but have been largely ignored in assessments of seismic hazard because their magnitudes are well below the detection thresholds of seismic networks. The total number of locatable microearthquakes could be dramatically increased by lowering the triggering thresholds of network detection algorithms. The present work offers an example of how microearthquakes can be reliably detected and located with advanced techniques. This could make it possible to create a new database to identify subsurface fault geometries and modes of fault movement, which could then be considered in the assessments of seismic hazard in regions where major earthquakes are rare.

  7. Automatic Fault Characterization via Abnormality-Enhanced Classification

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bronevetsky, G; Laguna, I; de Supinski, B R

    Enterprise and high-performance computing systems are growing extremely large and complex, employing hundreds to hundreds of thousands of processors and software/hardware stacks built by many people across many organizations. As the growing scale of these machines increases the frequency of faults, system complexity makes these faults difficult to detect and to diagnose. Current system management techniques, which focus primarily on efficient data access and query mechanisms, require system administrators to examine the behavior of various system services manually. Growing system complexity is making this manual process unmanageable: administrators require more effective management tools that can detect faults and help tomore » identify their root causes. System administrators need timely notification when a fault is manifested that includes the type of fault, the time period in which it occurred and the processor on which it originated. Statistical modeling approaches can accurately characterize system behavior. However, the complex effects of system faults make these tools difficult to apply effectively. This paper investigates the application of classification and clustering algorithms to fault detection and characterization. We show experimentally that naively applying these methods achieves poor accuracy. Further, we design novel techniques that combine classification algorithms with information on the abnormality of application behavior to improve detection and characterization accuracy. Our experiments demonstrate that these techniques can detect and characterize faults with 65% accuracy, compared to just 5% accuracy for naive approaches.« less

  8. A Genetic Representation for Evolutionary Fault Recovery in Virtex FPGAs

    NASA Technical Reports Server (NTRS)

    Lohn, Jason; Larchev, Greg; DeMara, Ronald; Korsmeyer, David (Technical Monitor)

    2003-01-01

    Most evolutionary approaches to fault recovery in FPGAs focus on evolving alternative logic configurations as opposed to evolving the intra-cell routing. Since the majority of transistors in a typical FPGA are dedicated to interconnect, nearly 80% according to one estimate, evolutionary fault-recovery systems should benefit hy accommodating routing. In this paper, we propose an evolutionary fault-recovery system employing a genetic representation that takes into account both logic and routing configurations. Experiments were run using a software model of the Xilinx Virtex FPGA. We report that using four Virtex combinational logic blocks, we were able to evolve a 100% accurate quadrature decoder finite state machine in the presence of a stuck-at-zero fault.

  9. Geophysical Survey of Proposed Construction Site with Possible Faulting, East San Francisco Bay Hills, California

    NASA Astrophysics Data System (ADS)

    Galvin, J. L.; Deqiang, C.; Abimbola, A.; Shuler, S.; Hayashi, K.; Fox, J.; Craig, M. S.; Strayer, L. M.; Drumm, P.

    2015-12-01

    We conducted a geophysical study at a site proposed for a new dorm building prior to trenching planned as part of a separate fault investigation study. The study area was located on the south side of the CSU East Bay campus, roughly 100 - 300 m SSE of the current dorm complex. In addition to its proximity to the Hayward Fault, several smaller faults have been previously mapped within the proposed location, including the East and West Dibblee Faults. These faults are thought to represent contacts between the Leona Rhyolite and the Knoxville Formation. Data acquisition included seismic, resistivity, and GPS data collected in an effort to develop a better understanding of the geological and structural profile of this area, including the location of lithologic contacts, faults, and the thickness of soil and fill. Geophysical profiles were collected over the locations of future trenches. The survey included geophysical lines that were located coincident with two planned trenching sites, which were chosen to intersect mapped faults. Survey positions were recorded using differential GPS. Seismic refraction and MASW (multichannel analysis of surface waves) surveys were performed over two of the planned trench sites using a 48-channel seismographic system with 4.5 Hz geophones and a 10-lb sledgehammer. For one of the lines, geophones were spaced every 3 m with a total spread length of 141 m and a shot spacing of 9 m. For the second line, geophones were spaced every 4 m with a total spread length of 188 m. Shots were taken every 12 m. Resistivity surveys were also performed along one of the line locations using both a capacitively-coupled dipole (CCD) system and 48-electrode system. Geospatial data for the survey area were compiled, including 0.3 m color orthoimagery and vector line files for geologic unit boundaries and presumed fault locations. The products of this study will include the geophysical response of geologic formations, location of unit contacts and faults

  10. Micro-geomorphology Surveying and Analysis of Xiadian Fault Scarp, China

    NASA Astrophysics Data System (ADS)

    Ding, R.

    2014-12-01

    Historic records and field investigations reveal that the Mw 8.0 Sanhe-Pinggu (China) earthquake of 1679 produced a 10 to 18 km-long surface rupture zone, with dominantly dip-slip accompanied by a right-lateral component along the Xiadian fault, resulting in extensive damage throughout north China. The fault scarp that was coursed by the co-seismic ruptures from Dongliuhetun to Pangezhang is about 1 to 3 meters high, and the biggest vertical displacement locates in Pangezhuang, it is easily to be seen in the flat alluvial plain. But the 10 to 18 km-long surface rupture couldn't match the Mw 8.0 earthquake scale. After more than 300 years land leveling, the fault scarps in the meizoseismal zone which is farmland are retreat at different degree, some small scarps are becoming disappeared, so it is hard to identify by visual observation in the field investigations. The meizoseismal zone is located in the alluvial plain of the Chaobai river and Jiyun river, and the fault is perpendicular to the river. It is easy to distinguish fault scarps from erosion scarps. Land leveling just changes the slope of the fault scarp, but it can't eliminate the height difference between two side of the fault. So it is possible to recover the location and height of the fault scarp by using Digital Elevation Model (DEM) analysis and landform surveying which is constrained by 3D centimeter-precision RTK GPS surveying method in large scale crossing the fault zone. On the base of the high-precision DEM landform analysis, we carried out 15 GPS surveying lines which extends at least 10km for each crossing the meizoseismal zone. Our findings demonstrate that 1) we recover the complete rupture zone of the Sanhe-Pinggu earthquake in 1679, and survey the co-seismic displacement at 15 sites; 2) we conform that the Xiadian fault scarp is consist of three branches with left stepping. Height of the scarp is from 0.5 to 4.0 meters, and the total length of the scarp is at least 50km; 3) Combined with the

  11. Logs of Paleoseismic Excavations Across the Central Range Fault, Trinidad

    USGS Publications Warehouse

    Crosby, Christopher J.; Prentice, Carol S.; Weber, John; Ragona, Daniel

    2009-01-01

    This publication makes available maps and trench logs associated with studies of the Central Range Fault, part of the South American-Caribbean plate boundary in Trinidad. Our studies were conducted in 2001 and 2002. We mapped geomorphic features indicative of active faulting along the right-lateral, Central Range Fault, part of the South American-Caribbean plate boundary in Trinidad. We excavated trenches at two sites, the Samlalsingh and Tabaquite sites. At the Samlalsingh site, sediments deposited after the most recent fault movement bury the fault, and the exact location of the fault was unknown until we exposed it in our excavations. At this site, we excavated a total of eleven trenches, six of which exposed the fault. The trenches exposed fluvial sediments deposited over a strath terrace developed on Miocene bedrock units. We cleaned the walls of the excavations, gridded the walls with either 1 m X 1 m or 1 m X 0.5 m nail and string grid, and logged the walls in detail at a scale of 1:20. Additionally, we described the different sedimentary units in the field, incorporating these descriptions into our trench logs. We mapped the locations of the trenches using a tape and compass. Our field logs were scanned, and unit contacts were traced in Adobe Illustrator. The final drafted logs of all the trenches are presented here, along with photographs showing important relations among faults and Holocene sedimentary deposits. Logs of south walls were reversed in Illustrator, so that all logs are drafted with the view direction to the north. We collected samples of various materials exposed in the trench walls, including charcoal samples for radiocarbon dating from both faulted and unfaulted deposits. The locations of all samples collected are shown on the logs. The ages of seventeen of the charcoal samples submitted for radiocarbon analysis at the University of Arizona Accelerator Mass Spectrometry Laboratory in Tucson, Ariz., are given in Table 1. Samples found in

  12. Geophysical study of the Ota-VF Xira-Lisbon-Sesimbra fault zone and the lower Tagus Cenozoic basin

    NASA Astrophysics Data System (ADS)

    Carvalho, João; Rabeh, Taha; Bielik, Miroslav; Szalaiová, Eva; Torres, Luís; Silva, Marisa; Carrilho, Fernando; Matias, Luís; Miranda, Jorge Miguel

    2011-09-01

    This paper focuses on the interpretation of seismic reflection, gravimetric, topographic, deep seismic refraction and seismicity data to study the recently proposed Ota-Vila Franca de Xira-Lisbon-Sesimbra (OVLS) fault zone and the lower Tagus Cenozoic basin (LTCB). The studied structure is located in the lower Tagus valley (LTV), an area with over 2 million inhabitants that has experienced historical earthquakes which caused significant damage and economical losses (1344, 1531 and 1909 earthquakes) and whose tectonic sources are thought to be local but mostly remain unknown. This study, which is intended as a contribution to improve the seismic hazard of the area and the neotectonics of the region, shows that the above-proposed fault zone is probably a large crustal thrust fault that constitutes the western limit of the LTCB. Gravimetric, deep refraction and seismic reflection data suggest that the LTCB is a foreland basin, as suggested previously by some authors, and that the OVLS northern and central sectors act as the major thrusts. The southern sector fault has been dominated by strike-slip kinematics due to a different orientation to the stress field. Indeed, geological outcrop and seismic reflection data interpretation suggests that, based on fault geometry and type of deformation at depth, the structure is composed of three major segments. These data suggest that these segments have different kinematics in agreement with their orientation to the regional stress field. The OVLS apparently controls the distribution of the seismicity in the area. Geological and geophysical information previously gathered also points that the central segment is active into the Quaternary. The segment lengths vary between 20 and 45 km. Since faults usually rupture only by segments, maximum expectable earthquake magnitudes and other parameters have been calculated for the three sectors of the OVLS fault zone using empirical relationships between earthquake statistics and

  13. Distributed adaptive diagnosis of sensor faults using structural response data

    NASA Astrophysics Data System (ADS)

    Dragos, Kosmas; Smarsly, Kay

    2016-10-01

    The reliability and consistency of wireless structural health monitoring (SHM) systems can be compromised by sensor faults, leading to miscalibrations, corrupted data, or even data loss. Several research approaches towards fault diagnosis, referred to as ‘analytical redundancy’, have been proposed that analyze the correlations between different sensor outputs. In wireless SHM, most analytical redundancy approaches require centralized data storage on a server for data analysis, while other approaches exploit the on-board computing capabilities of wireless sensor nodes, analyzing the raw sensor data directly on board. However, using raw sensor data poses an operational constraint due to the limited power resources of wireless sensor nodes. In this paper, a new distributed autonomous approach towards sensor fault diagnosis based on processed structural response data is presented. The inherent correlations among Fourier amplitudes of acceleration response data, at peaks corresponding to the eigenfrequencies of the structure, are used for diagnosis of abnormal sensor outputs at a given structural condition. Representing an entirely data-driven analytical redundancy approach that does not require any a priori knowledge of the monitored structure or of the SHM system, artificial neural networks (ANN) are embedded into the sensor nodes enabling cooperative fault diagnosis in a fully decentralized manner. The distributed analytical redundancy approach is implemented into a wireless SHM system and validated in laboratory experiments, demonstrating the ability of wireless sensor nodes to self-diagnose sensor faults accurately and efficiently with minimal data traffic. Besides enabling distributed autonomous fault diagnosis, the embedded ANNs are able to adapt to the actual condition of the structure, thus ensuring accurate and efficient fault diagnosis even in case of structural changes.

  14. Recently Active Traces of the Berryessa Fault, California: A Digital Database

    USGS Publications Warehouse

    Lienkaemper, James J.

    2012-01-01

    The purpose of this map is to show the location of and evidence for recent movement on active fault traces within the Berryessa section and parts of adjacent sections of the Green Valley Fault Zone, California. The location and recency of the mapped traces is primarily based on geomorphic expression of the fault as interpreted from large-scale 2010 aerial photography and from 2007 and 2011 0.5 and 1.0 meter bare-earth LiDAR imagery (that is, high-resolution topographic data). In a few places, evidence of fault creep and offset Holocene strata in trenches and natural exposures have confirmed the activity of some of these traces. This publication is formatted both as a digital database for use within a geographic information system (GIS) and for broader public access as map images that may be browsed on-line or download a summary map. The report text describes the types of scientific observations used to make the map, gives references pertaining to the fault and the evidence of faulting, and provides guidance for use of and limitations of the map.

  15. Lightning location system supervising Swedish power transmission network

    NASA Technical Reports Server (NTRS)

    Melin, Stefan A.

    1991-01-01

    For electric utilities, the ability to prevent or minimize lightning damage on personnel and power systems is of great importance. Therefore, the Swedish State Power Board, has been using data since 1983 from a nationwide lightning location system (LLS) for accurately locating lightning ground strikes. Lightning data is distributed and presented on color graphic displays at regional power network control centers as well as at the national power system control center for optimal data use. The main objectives for use of LLS data are: supervising the power system for optimal and safe use of the transmission and generating capacity during periods of thunderstorms; warning service to maintenance and service crews at power line and substations to end operations hazardous when lightning; rapid positioning of emergency crews to locate network damage at areas of detected lightning; and post analysis of power outages and transmission faults in relation to lightning, using archived lightning data for determination of appropriate design and insulation levels of equipment. Staff have found LLS data useful and economically justified since the availability of power system has increased as well as level of personnel safety.

  16. Real-time Estimation of Fault Rupture Extent for Recent Large Earthquakes

    NASA Astrophysics Data System (ADS)

    Yamada, M.; Mori, J. J.

    2009-12-01

    Current earthquake early warning systems assume point source models for the rupture. However, for large earthquakes, the fault rupture length can be of the order of tens to hundreds of kilometers, and the prediction of ground motion at a site requires the approximated knowledge of the rupture geometry. Early warning information based on a point source model may underestimate the ground motion at a site, if a station is close to the fault but distant from the epicenter. We developed an empirical function to classify seismic records into near-source (NS) or far-source (FS) records based on the past strong motion records (Yamada et al., 2007). Here, we defined the near-source region as an area with a fault rupture distance less than 10km. If we have ground motion records at a station, the probability that the station is located in the near-source region is; P = 1/(1+exp(-f)) f = 6.046log10(Za) + 7.885log10(Hv) - 27.091 where Za and Hv denote the peak values of the vertical acceleration and horizontal velocity, respectively. Each observation provides the probability that the station is located in near-source region, so the resolution of the proposed method depends on the station density. The information of the fault rupture location is a group of points where the stations are located. However, for practical purposes, the 2-dimensional configuration of the fault is required to compute the ground motion at a site. In this study, we extend the methodology of NS/FS classification to characterize 2-dimensional fault geometries and apply them to strong motion data observed in recent large earthquakes. We apply a cosine-shaped smoothing function to the probability distribution of near-source stations, and convert the point fault location to 2-dimensional fault information. The estimated rupture geometry for the 2007 Niigata-ken Chuetsu-oki earthquake 10 seconds after the origin time is shown in Figure 1. Furthermore, we illustrate our method with strong motion data of the

  17. Determination of Seismic Activity on the Main Marmara Fault with GPS Measurements

    NASA Astrophysics Data System (ADS)

    Alkan, M. N.; Alkan, R. M.; Yavaşoğlu, H.; Köse, Z.; Aladoğan, K.; Özbey, V.

    2017-12-01

    The tectonic plates that creates the Earth have always been an important topic to work on for Geosciences. Plate motion affecting the Earth's crust have occurred for millions of years. This slow but continuous movement that has been going on for millions of years can only be followed by instrumental measurements. In recent years, this process has been done with GPS very accurately. The North Anatolian Fault (NAF) is a major right-lateral, strike-slip fault that extends more than 1200 km extends along all North Anatolia from Bingol to Saros Gulf. The NAFZ is divided into Southern and Northern Branches to the east of Marmara region that several destructive earthquakes occurred, such as Izmit (in 1999, Mw=7.4) and Duzce (in 1999, Mw=7.2) in the last century. MMF (Main Marmara Fault) which is the part of the Northern Branch in the Marmara Sea, starting in from the Gulf of Izmit-Adapazarı and reaching the Gulf of Saros. The determination of the deformation accumulated on the MMF has become extremely important especially after the 1999 Izmit earthquake. According to the recent studies, the MMF is the largest unbroken part of the fault and is divided into segments. These segments are Cinarcik, Prince Island, Central Marmara and Tekirdag. Recent studies have demonstrated that the Prince Island segment is fully locked. However, studies that are focused on the Central Marmara segment, that is located offshore Istanbul, a giant metropole that has more than 14 million populations, do not conclude about the presence of a seismic gap, capable of generating a big earthquake. Therefore, in the scope of this study, a new GPS network was established at short and long distance from the Main Marmara Fault, to densify the existing GPS network. 3 campaign GPS measurements were done in 2015, 2016, 2017. The evaluation of the datasets were done by GAMIT/GLOBK software. For the evaluation, 30 continuous observation stations, 14 stations connected to the IGS network and 16 stations

  18. Illite authigenesis during faulting and fluid flow - a microstructural study of fault rocks

    NASA Astrophysics Data System (ADS)

    Scheiber, Thomas; Viola, Giulio; van der Lelij, Roelant; Margreth, Annina

    2017-04-01

    Authigenic illite can form synkinematically during slip events along brittle faults. In addition it can also crystallize as a result of fluid flow and associated mineral alteration processes in hydrothermal environments. K-Ar dating of illite-bearing fault rocks has recently become a common tool to constrain the timing of fault activity. However, to fully interpret the derived age spectra in terms of deformation ages, a careful investigation of the fault deformation history and architecture at the outcrop-scale, ideally followed by a detailed mineralogical analysis of the illite-forming processes at the micro-scale, are indispensable. Here we integrate this methodological approach by presenting microstructural observations from the host rock immediately adjacent to dated fault gouges from two sites located in the Rolvsnes granodiorite (Bømlo, western Norway). This granodiorite experienced multiple episodes of brittle faulting and fluid-induced alteration, starting in the Mid Ordovician (Scheiber et al., 2016). Fault gouges are predominantly associated with normal faults accommodating mainly E-W extension. K-Ar dating of illites separated from representative fault gouges constrains deformation and alteration due to fluid ingress from the Permian to the Cretaceous, with a cluster of ages for the finest (<0.1 µm) fraction in the early to middle Jurassic. At site one, high-resolution thin section structural mapping reveals a complex deformation history characterized by several coexisting types of calcite veins and seven different generations of cataclasite, two of which contain a significant amount of authigenic and undoubtedly deformation-related illite. At site two, fluid ingress along and adjoining the fault core induced pervasive alteration of the host granodiorite. Quartz is crosscut by calcite veinlets whereas plagioclase, K-feldspar and biotite are almost completely replaced by the main alteration products kaolin, quartz and illite. Illite-bearing micro

  19. Association of earthquakes and faults in the San Francisco Bay area using Bayesian inference

    USGS Publications Warehouse

    Wesson, R.L.; Bakun, W.H.; Perkins, D.M.

    2003-01-01

    Bayesian inference provides a method to use seismic intensity data or instrumental locations, together with geologic and seismologic data, to make quantitative estimates of the probabilities that specific past earthquakes are associated with specific faults. Probability density functions are constructed for the location of each earthquake, and these are combined with prior probabilities through Bayes' theorem to estimate the probability that an earthquake is associated with a specific fault. Results using this method are presented here for large, preinstrumental, historical earthquakes and for recent earthquakes with instrumental locations in the San Francisco Bay region. The probabilities for individual earthquakes can be summed to construct a probabilistic frequency-magnitude relationship for a fault segment. Other applications of the technique include the estimation of the probability of background earthquakes, that is, earthquakes not associated with known or considered faults, and the estimation of the fraction of the total seismic moment associated with earthquakes less than the characteristic magnitude. Results for the San Francisco Bay region suggest that potentially damaging earthquakes with magnitudes less than the characteristic magnitudes should be expected. Comparisons of earthquake locations and the surface traces of active faults as determined from geologic data show significant disparities, indicating that a complete understanding of the relationship between earthquakes and faults remains elusive.

  20. The Study of Fault Lineament Pattern of the Lamongan Volcanic Field Using Gravity Data

    NASA Astrophysics Data System (ADS)

    Aziz, K. N.; Hartantyo, E.; Niasari, S. W.

    2018-04-01

    Lamongan Volcano located in Tiris, East Java, possesses geothermal potential energy. The geothermal potential was indicated by the presence of geothermal manifestations such as hot springs. We usedsecondary gravity data from GGMplus. The result of gravity anomaly map shows that there is the lowest gravity anomaly in the center of the study area coinciding with the hot spring location. Gravity data were analyzed using SVD method to identify fault structures. It controls the geothermal fluid pathways. The result of this research shows thatthe type of fault in hot springsisanormal fault with direction NW-SE. The fault lineament pattern along maaris NW-SE.Maar indicates anormal fault. As the result we know that gravity data from GGMplus which analyzed with SVD can be used to determine the type and trend of fault.

  1. Accurate relocation of seismicity along the North Aegean Trough and its relation to active tectonics

    NASA Astrophysics Data System (ADS)

    Konstantinou, K. I.

    2017-10-01

    The tectonics of northern Aegean are affected by the westward push of Anatolia and the gravitational spreading of the Aegean lithosphere that promote transtensional deformation in the area. This regime is also responsible for the creation of a series of pull-apart basins, collectively known as the North Aegean Trough. This work accurately relocates a total of 2300 earthquakes that were recorded along the North Aegean Trough during 2011-2016 by stations of the Hellenic Unified Seismic Network (HUSN) and strong-motion sensors. Absolute locations for these events were obtained using a nonlinear probabilistic algorithm and utilizing a minimum 1D velocity model with station corrections. The hypocentral depth distribution of these events shows a peak at 8 km diminishing gradually down to 20 km. A systematic overestimation of hypocentral depths is observed in the routine locations provided by the National Observatory of Athens where the majority of events appear to be deeper than 15 km. In order to obtain more accurate relative locations these events were relocated using the double-difference method. A total of 1693 events were finally relocated with horizontal and vertical uncertainties that do not exceed 0.11 km and 0.22 km respectively. Well-defined clusters of seismicity can be observed along the Saros and Sporades basins as well as the Kassandra and Sithonia peninsulas. These clusters either occur along the well-known NE-SW strike-slip faults bounding the basins, or along normal faults whose strike is perpendicular to the regional minimum stress axis. Locking depth along the North Aegean Trough is found to be remarkably stable between 13 and 17 km. This is likely a consequence of simultaneous reduction along the SW direction of heat flow (from 89 to 51 mW/m2) and strain rate (from 600 to 50 nstrain/yr) whose opposite effects are canceled out, precluding any sharp changes in locking depth.

  2. Fault Diagnosis of Power Systems Using Intelligent Systems

    NASA Technical Reports Server (NTRS)

    Momoh, James A.; Oliver, Walter E. , Jr.

    1996-01-01

    The power system operator's need for a reliable power delivery system calls for a real-time or near-real-time Al-based fault diagnosis tool. Such a tool will allow NASA ground controllers to re-establish a normal or near-normal degraded operating state of the EPS (a DC power system) for Space Station Alpha by isolating the faulted branches and loads of the system. And after isolation, re-energizing those branches and loads that have been found not to have any faults in them. A proposed solution involves using the Fault Diagnosis Intelligent System (FDIS) to perform near-real time fault diagnosis of Alpha's EPS by downloading power transient telemetry at fault-time from onboard data loggers. The FDIS uses an ANN clustering algorithm augmented with a wavelet transform feature extractor. This combination enables this system to perform pattern recognition of the power transient signatures to diagnose the fault type and its location down to the orbital replaceable unit. FDIS has been tested using a simulation of the LeRC Testbed Space Station Freedom configuration including the topology from the DDCU's to the electrical loads attached to the TPDU's. FDIS will work in conjunction with the Power Management Load Scheduler to determine what the state of the system was at the time of the fault condition. This information is used to activate the appropriate diagnostic section, and to refine if necessary the solution obtained. In the latter case, if the FDIS reports back that it is equally likely that the faulty device as 'start tracker #1' and 'time generation unit,' then based on a priori knowledge of the system's state, the refined solution would be 'star tracker #1' located in cabinet ITAS2. It is concluded from the present studies that artificial intelligence diagnostic abilities are improved with the addition of the wavelet transform, and that when such a system such as FDIS is coupled to the Power Management Load Scheduler, a faulty device can be located and isolated

  3. Arc Fault Detection & Localization by Electromagnetic-Acoustic Remote Sensing

    NASA Astrophysics Data System (ADS)

    Vasile, C.; Ioana, C.

    2017-05-01

    Electrical arc faults that occur in photovoltaic systems represent a danger due to their economic impact on production and distribution. In this paper we propose a complete system, with focus on the methodology, that enables the detection and localization of the arc fault, by the use of an electromagnetic-acoustic sensing system. By exploiting the multiple emissions of the arc fault, in conjunction with a real-time detection signal processing method, we ensure accurate detection and localization. In its final form, this present work will present in greater detail the complete system, the methods employed, results and performance, alongside further works that will be carried on.

  4. Heterogeneity in the Fault Damage Zone: a Field Study on the Borrego Fault, B.C., Mexico

    NASA Astrophysics Data System (ADS)

    Ostermeijer, G.; Mitchell, T. M.; Dorsey, M. T.; Browning, J.; Rockwell, T. K.; Aben, F. M.; Fletcher, J. M.; Brantut, N.

    2017-12-01

    The nature and distribution of damage around faults, and its impacts on fault zone properties has been a hot topic of research over the past decade. Understanding the mechanisms that control the formation of off fault damage can shed light on the processes during the seismic cycle, and the nature of fault zone development. Recent published work has identified three broad zones of damage around most faults based on the type, intensity, and extent of fracturing; Tip, Wall, and Linking damage. Although these zones are able to adequately characterise the general distribution of damage, little has been done to identify the nature of damage heterogeneity within those zones, often simplifying the distribution to fit log-normal linear decay trends. Here, we attempt to characterise the distribution of fractures that make up the wall damage around seismogenic faults. To do so, we investigate an extensive two dimensional fracture network exposed on a river cut platform along the Borrego Fault, BC, Mexico, 5m wide, and extending 20m from the fault core into the damage zone. High resolution fracture mapping of the outcrop, covering scales ranging three orders of magnitude (cm to m), has allowed for detailed observations of the 2D damage distribution within the fault damage zone. Damage profiles were obtained along several 1D transects perpendicular to the fault and micro-damage was examined from thin-sections at various locations around the outcrop for comparison. Analysis of the resulting fracture network indicates heterogeneities in damage intensity at decimetre scales resulting from a patchy distribution of high and low intensity corridors and clusters. Such patchiness may contribute to inconsistencies in damage zone widths defined along 1D transects and the observed variability of fracture densities around decay trends. How this distribution develops with fault maturity and the scaling of heterogeneities above and below the observed range will likely play a key role in

  5. Looking for Off-Fault Deformation and Measuring Strain Accumulation During the Past 70 years on a Portion of the Locked San Andreas Fault

    NASA Astrophysics Data System (ADS)

    Vadman, M.; Bemis, S. P.

    2017-12-01

    Even at high tectonic rates, detection of possible off-fault plastic/aseismic deformation and variability in far-field strain accumulation requires high spatial resolution data and likely decades of measurements. Due to the influence that variability in interseismic deformation could have on the timing, size, and location of future earthquakes and the calculation of modern geodetic estimates of strain, we attempt to use historical aerial photographs to constrain deformation through time across a locked fault. Modern photo-based 3D reconstruction techniques facilitate the creation of dense point clouds from historical aerial photograph collections. We use these tools to generate a time series of high-resolution point clouds that span 10-20 km across the Carrizo Plain segment of the San Andreas fault. We chose this location due to the high tectonic rates along the San Andreas fault and lack of vegetation, which may obscure tectonic signals. We use ground control points collected with differential GPS to establish scale and georeference the aerial photograph-derived point clouds. With a locked fault assumption, point clouds can be co-registered (to one another and/or the 1.7 km wide B4 airborne lidar dataset) along the fault trace to calculate relative displacements away from the fault. We use CloudCompare to compute 3D surface displacements, which reflect the interseismic strain accumulation that occurred in the time interval between photo collections. As expected, we do not observe clear surface displacements along the primary fault trace in our comparisons of the B4 lidar data against the aerial photograph-derived point clouds. However, there may be small scale variations within the lidar swath area that represent near-fault plastic deformation. With large-scale historical photographs available for the Carrizo Plain extending back to at least the 1940s, we can potentially sample nearly half the interseismic period since the last major earthquake on this portion of

  6. Delineation of faulting and basin geometry along a seismic reflection transect in urbanized San Bernardino Valley, California

    USGS Publications Warehouse

    Stephenson, W.J.; Odum, J.K.; Williams, R.A.; Anderson, M.L.

    2002-01-01

    Fourteen kilometers of continuous, shallow seismic reflection data acquired through the urbanized San Bernardino Valley, California, have revealed numerous faults between the San Jacinto and San Andreas faults as well as a complex pattern of downdropped and uplifted blocks. These data also indicate that the Loma Linda fault continues northeastward at least 4.5 km beyond its last mapped location on the southern edge of the valley and to within at least 2 km of downtown San Bernardino. Previously undetected faults within the valley northeast of the San Jacinto fault are also imaged, including the inferred western extension of the Banning fault and several unnamed faults. The Rialto-Colton fault is interpreted southwest of the San Jacinto fault. The seismic data image the top of the crystalline basement complex across 70% of the profile length and show that the basement has an overall dip of roughly 10?? southwest between Perris Hill and the San Jacinto fault. Gravity and aeromagnetic data corroborate the interpreted location of the San Jacinto fault and better constrain the basin depth along the seismic profile to be as deep as 1.7 km. These data also corroborate other fault locations and the general dip of the basement surface. At least 1.2 km of apparent vertical displacement on the basement is observed across the San Jacinto fault at the profile location. The basin geometry delineated by these data was used to generate modeled ground motions that show peak horizontal amplifications of 2-3.5 above bedrock response in the 0.05- to 1.0-Hz frequency band, which is consistent with recorded earthquake data in the valley.

  7. Methods for locating ground faults and insulation degradation condition in energy conversion systems

    DOEpatents

    Agamy, Mohamed; Elasser, Ahmed; Galbraith, Anthony William; Harfman Todorovic, Maja

    2015-08-11

    Methods for determining a ground fault or insulation degradation condition within energy conversion systems are described. A method for determining a ground fault within an energy conversion system may include, in part, a comparison of baseline waveform of differential current to a waveform of differential current during operation for a plurality of DC current carrying conductors in an energy conversion system. A method for determining insulation degradation within an energy conversion system may include, in part, a comparison of baseline frequency spectra of differential current to a frequency spectra of differential current transient at start-up for a plurality of DC current carrying conductors in an energy conversion system. In one embodiment, the energy conversion system may be a photovoltaic system.

  8. Using a modified time-reverse imaging technique to locate low-frequency earthquakes on the San Andreas Fault near Cholame, California

    USGS Publications Warehouse

    Horstmann, Tobias; Harrington, Rebecca M.; Cochran, Elizabeth S.

    2015-01-01

    We present a new method to locate low-frequency earthquakes (LFEs) within tectonic tremor episodes based on time-reverse imaging techniques. The modified time-reverse imaging technique presented here is the first method that locates individual LFEs within tremor episodes within 5 km uncertainty without relying on high-amplitude P-wave arrivals and that produces similar hypocentral locations to methods that locate events by stacking hundreds of LFEs without having to assume event co-location. In contrast to classic time-reverse imaging algorithms, we implement a modification to the method that searches for phase coherence over a short time period rather than identifying the maximum amplitude of a superpositioned wavefield. The method is independent of amplitude and can help constrain event origin time. The method uses individual LFE origin times, but does not rely on a priori information on LFE templates and families.We apply the method to locate 34 individual LFEs within tremor episodes that occur between 2010 and 2011 on the San Andreas Fault, near Cholame, California. Individual LFE location accuracies range from 2.6 to 5 km horizontally and 4.8 km vertically. Other methods that have been able to locate individual LFEs with accuracy of less than 5 km have mainly used large-amplitude events where a P-phase arrival can be identified. The method described here has the potential to locate a larger number of individual low-amplitude events with only the S-phase arrival. Location accuracy is controlled by the velocity model resolution and the wavelength of the dominant energy of the signal. Location results are also dependent on the number of stations used and are negligibly correlated with other factors such as the maximum gap in azimuthal coverage, source–station distance and signal-to-noise ratio.

  9. Lacustrine Paleoseismology Reveals Earthquake Segmentation of the Alpine Fault, New Zealand

    NASA Astrophysics Data System (ADS)

    Howarth, J. D.; Fitzsimons, S.; Norris, R.; Langridge, R. M.

    2013-12-01

    Transform plate boundary faults accommodate high rates of strain and are capable of producing large (Mw>7.0) to great (Mw>8.0) earthquakes that pose significant seismic hazard. The Alpine Fault in New Zealand is one of the longest, straightest and fastest slipping plate boundary transform faults on Earth and produces earthquakes at quasi-periodic intervals. Theoretically, the fault's linearity, isolation from other faults and quasi-periodicity should promote the generation of earthquakes that have similar magnitudes over multiple seismic cycles. We test the hypothesis that the Alpine Fault produces quasi-regular earthquakes that contiguously rupture the southern and central fault segments, using a novel lacustrine paleoseismic proxy to reconstruct spatial and temporal patterns of fault rupture over the last 2000 years. In three lakes located close to the Alpine Fault the last nine earthquakes are recorded as megaturbidites formed by co-seismic subaqueous slope failures, which occur when shaking exceeds Modified Mercalli (MM) VII. When the fault ruptures adjacent to a lake the co-seismic megaturbidites are overlain by stacks of turbidites produced by enhanced fluvial sediment fluxes from earthquake-induced landslides. The turbidite stacks record shaking intensities of MM>IX in the lake catchments and can be used to map the spatial location of fault rupture. The lake records can be dated precisely, facilitating meaningful along strike correlations, and the continuous records allow earthquakes closely spaced in time on adjacent fault segments to be distinguished. The results show that while multi-segment ruptures of the Alpine Fault occurred during most seismic cycles, sequential earthquakes on adjacent segments and single segment ruptures have also occurred. The complexity of the fault rupture pattern suggests that the subtle variations in fault geometry, sense of motion and slip rate that have been used to distinguish the central and southern segments of the Alpine

  10. Imaging shear strength along subduction faults

    USGS Publications Warehouse

    Bletery, Quentin; Thomas, Amanda M.; Rempel, Alan W.; Hardebeck, Jeanne L.

    2017-01-01

    Subduction faults accumulate stress during long periods of time and release this stress suddenly, during earthquakes, when it reaches a threshold. This threshold, the shear strength, controls the occurrence and magnitude of earthquakes. We consider a 3-D model to derive an analytical expression for how the shear strength depends on the fault geometry, the convergence obliquity, frictional properties, and the stress field orientation. We then use estimates of these different parameters in Japan to infer the distribution of shear strength along a subduction fault. We show that the 2011 Mw9.0 Tohoku earthquake ruptured a fault portion characterized by unusually small variations in static shear strength. This observation is consistent with the hypothesis that large earthquakes preferentially rupture regions with relatively homogeneous shear strength. With increasing constraints on the different parameters at play, our approach could, in the future, help identify favorable locations for large earthquakes.

  11. Preliminary Pseudo 3-D Imagery of the State Line Fault, Stewart Valley, Nevada Using Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Saldaña, S. C.; Snelson, C. M.; Taylor, W. J.; Beachly, M.; Cox, C. M.; Davis, R.; Stropky, M.; Phillips, R.; Robins, C.; Cothrun, C.

    2007-12-01

    The Pahrump Fault system is located in the central Basin and Range region and consists of three main fault zones: the Nopah range front fault zone, the State Line fault zone and the Spring Mountains range fault zone. The State Line fault zone is made up north-west trending dextral strike-slip faults that run parallel to the Nevada- California border. Previous geologic and geophysical studies conducted in and around Stewart Valley, located ~90 km from Las Vegas, Nevada, have constrained the location of the State Line fault zone to within a few kilometers. The goals of this project were to use seismic methods to definitively locate the northwestern most trace of the State Line fault and produce pseudo 3-D seismic cross-sections that can then be used to characterize the subsurface geometry and determine the slip of the State Line fault. During July 2007, four seismic lines were acquired in Stewart Valley: two normal and two parallel to the mapped traces of the State Line fault. Presented here are preliminary results from the two seismic lines acquired normal to the fault. These lines were acquired utilizing a 144-channel geode system with each of the 4.5 Hz vertical geophones set out at 5 m intervals to produce a 595 m long profile to the north and a 715 m long profile to the south. The vibroseis was programmed to produce an 8 s linear sweep from 20-160 Hz. These data returned excellent signal to noise and reveal subsurface lithology that will subsequently be used to resolve the subsurface geometry of the State Line fault. This knowledge will then enhance our understanding of the evolution of the State Line fault. Knowing how the State Line fault has evolved gives insight into the stick-slip fault evolution for the region and may improve understanding of how stress has been partitioned from larger strike-slip systems such as the San Andreas fault.

  12. Unsupervised Learning —A Novel Clustering Method for Rolling Bearing Faults Identification

    NASA Astrophysics Data System (ADS)

    Kai, Li; Bo, Luo; Tao, Ma; Xuefeng, Yang; Guangming, Wang

    2017-12-01

    To promptly process the massive fault data and automatically provide accurate diagnosis results, numerous studies have been conducted on intelligent fault diagnosis of rolling bearing. Among these studies, such as artificial neural networks, support vector machines, decision trees and other supervised learning methods are used commonly. These methods can detect the failure of rolling bearing effectively, but to achieve better detection results, it often requires a lot of training samples. Based on above, a novel clustering method is proposed in this paper. This novel method is able to find the correct number of clusters automatically the effectiveness of the proposed method is validated using datasets from rolling element bearings. The diagnosis results show that the proposed method can accurately detect the fault types of small samples. Meanwhile, the diagnosis results are also relative high accuracy even for massive samples.

  13. Rolling bearing fault detection and diagnosis based on composite multiscale fuzzy entropy and ensemble support vector machines

    NASA Astrophysics Data System (ADS)

    Zheng, Jinde; Pan, Haiyang; Cheng, Junsheng

    2017-02-01

    To timely detect the incipient failure of rolling bearing and find out the accurate fault location, a novel rolling bearing fault diagnosis method is proposed based on the composite multiscale fuzzy entropy (CMFE) and ensemble support vector machines (ESVMs). Fuzzy entropy (FuzzyEn), as an improvement of sample entropy (SampEn), is a new nonlinear method for measuring the complexity of time series. Since FuzzyEn (or SampEn) in single scale can not reflect the complexity effectively, multiscale fuzzy entropy (MFE) is developed by defining the FuzzyEns of coarse-grained time series, which represents the system dynamics in different scales. However, the MFE values will be affected by the data length, especially when the data are not long enough. By combining information of multiple coarse-grained time series in the same scale, the CMFE algorithm is proposed in this paper to enhance MFE, as well as FuzzyEn. Compared with MFE, with the increasing of scale factor, CMFE obtains much more stable and consistent values for a short-term time series. In this paper CMFE is employed to measure the complexity of vibration signals of rolling bearings and is applied to extract the nonlinear features hidden in the vibration signals. Also the physically meanings of CMFE being suitable for rolling bearing fault diagnosis are explored. Based on these, to fulfill an automatic fault diagnosis, the ensemble SVMs based multi-classifier is constructed for the intelligent classification of fault features. Finally, the proposed fault diagnosis method of rolling bearing is applied to experimental data analysis and the results indicate that the proposed method could effectively distinguish different fault categories and severities of rolling bearings.

  14. www.fallasdechile.cl, the First Online Repository for Neotectonic Faults in the Chilean Andes

    NASA Astrophysics Data System (ADS)

    Aron, F.; Salas, V.; Bugueño, C. J.; Hernández, C.; Leiva, L.; Santibanez, I.; Cembrano, J. M.

    2016-12-01

    We introduce the site www.fallasdechile.cl, created and maintained by undergraduate students and researchers at the Catholic University of Chile. Though the web page seeks to inform and educate the general public about potentially seismogenic faults of the country, layers of increasing content complexity allow students, researchers and educators to consult the site as a scientific tool as well. This is the first comprehensive, open access database on Chilean geologic faults; we envision that it may grow organically with contributions from peer scientists, resembling the SCEC community fault model for southern California. Our website aims at filling a gap between science and society providing users the opportunity to get involved by self-driven learning through interactive education modules. The main page highlights recent developments and open questions in Chilean earthquake science. Front pages show first level information of general concepts in earthquake topics such as tectonic settings, definition of geologic faults, and space-time constraints of faults. Users can navigate interactive modules to explore, with real data, different earthquake scenarios and compute values of seismic moment and magnitude. A second level covers Chilean/Andean faults classified according to their geographic location containing at least one of the following parameters: mapped trace, 3D geometry, sense of slip, recurrence times and date of last event. Fault traces are displayed on an interactive map using a Google Maps API. The material is compiled and curated in an effort to present, up to our knowledge, accurate and up to date information. If interested, the user can navigate to a third layer containing more advanced technical details including primary sources of the data, a brief structural description, published scientific articles, and links to other online content complementing our site. Also, geographically referenced fault traces with attributes (kml, shapefiles) and fault 3D

  15. Characterization of emission microscopy and liquid crystal thermography in IC fault localization

    NASA Astrophysics Data System (ADS)

    Lau, C. K.; Sim, K. S.

    2013-05-01

    This paper characterizes two fault localization techniques - Emission Microscopy (EMMI) and Liquid Crystal Thermography (LCT) by using integrated circuit (IC) leakage failures. The majority of today's semiconductor failures do not reveal a clear visual defect on the die surface and therefore require fault localization tools to identify the fault location. Among the various fault localization tools, liquid crystal thermography and frontside emission microscopy are commonly used in most semiconductor failure analysis laboratories. Many people misunderstand that both techniques are the same and both are detecting hot spot in chip failing with short or leakage. As a result, analysts tend to use only LCT since this technique involves very simple test setup compared to EMMI. The omission of EMMI as the alternative technique in fault localization always leads to incomplete analysis when LCT fails to localize any hot spot on a failing chip. Therefore, this research was established to characterize and compare both the techniques in terms of their sensitivity in detecting the fault location in common semiconductor failures. A new method was also proposed as an alternative technique i.e. the backside LCT technique. The research observed that both techniques have successfully detected the defect locations resulted from the leakage failures. LCT wass observed more sensitive than EMMI in the frontside analysis approach. On the other hand, EMMI performed better in the backside analysis approach. LCT was more sensitive in localizing ESD defect location and EMMI was more sensitive in detecting non ESD defect location. Backside LCT was proven to work as effectively as the frontside LCT and was ready to serve as an alternative technique to the backside EMMI. The research confirmed that LCT detects heat generation and EMMI detects photon emission (recombination radiation). The analysis results also suggested that both techniques complementing each other in the IC fault localization

  16. Subsidence and Fault Displacement Along the Long Point Fault Derived from Continuous GPS Observations (2012-2017)

    NASA Astrophysics Data System (ADS)

    Tsibanos, V.; Wang, G.

    2017-12-01

    The Long Point Fault located in Houston Texas is a complex system of normal faults which causes significant damage to urban infrastructure on both private and public property. This case study focuses on the 20-km long fault using high accuracy continuously operating global positioning satellite (GPS) stations to delineate fault movement over five years (2012 - 2017). The Long Point Fault is the longest active fault in the greater Houston area that damages roads, buried pipes, concrete structures and buildings and creates a financial burden for the city of Houston and the residents who live in close vicinity to the fault trace. In order to monitor fault displacement along the surface 11 permanent and continuously operating GPS stations were installed 6 on the hanging wall and 5 on the footwall. This study is an overview of the GPS observations from 2013 to 2017. GPS positions were processed with both relative (double differencing) and absolute Precise Point Positioning (PPP) techniques. The PPP solutions that are referred to IGS08 reference frame were transformed to the Stable Houston Reference Frame (SHRF16). Our results show no considerable horizontal displacements across the fault, but do show uneven vertical displacement attributed to regional subsidence in the range of (5 - 10 mm/yr). This subsidence can be associated to compaction of silty clays in the Chicot and Evangeline aquifers whose water depths are approximately 50m and 80m below the land surface (bls). These levels are below the regional pre-consolidation head that is about 30 to 40m bls. Recent research indicates subsidence will continue to occur until the aquifer levels reach the pre-consolidation head. With further GPS observations both the Long Point Fault and regional land subsidence can be monitored providing important geological data to the Houston community.

  17. Active tectonics of the Imperial Valley, southern California: fault damage zones, complex basins and buried faults

    NASA Astrophysics Data System (ADS)

    Persaud, P.; Ma, Y.; Stock, J. M.; Hole, J. A.; Fuis, G. S.; Han, L.

    2016-12-01

    Ongoing oblique slip at the Pacific-North America plate boundary in the Salton Trough produced the Imperial Valley. Deformation in this seismically active area is distributed across a complex network of exposed and buried faults resulting in a largely unmapped seismic hazard beneath the growing population centers of El Centro, Calexico and Mexicali. To better understand the shallow crustal structure in this region and the connectivity of faults and seismicity lineaments, we used data primarily from the Salton Seismic Imaging Project (SSIP) to construct a P-wave velocity profile to 15 km depth, and a 3-D velocity model down to 8 km depth including the Brawley Geothermal area. We obtained detailed images of a complex wedge-shaped basin at the southern end of the San Andreas Fault system. Two deep subbasins (VP <5.65 km/s) are located in the western part of the larger Imperial Valley basin, where seismicity trends and active faults play a significant role in shaping the basin edge. Our 3-D VP model reveals previously unrecognized NE-striking cross faults that are interacting with the dominant NW-striking faults to control deformation. New findings in our profile include localized regions of low VP (thickening of a 5.65-5.85 km/s layer) near faults or seismicity lineaments interpreted as possibly faulting-related. Our 3-D model and basement map reveal velocity highs associated with the geothermal areas in the eastern valley. The improved seismic velocity model from this study, and the identification of important unmapped faults or buried interfaces will help refine the seismic hazard for parts of Imperial County, California.

  18. Fault Activity in the Terrebonne Trough, Southeastern Louisiana: A Continuation of Salt-Withdrawal Fault Activity from the Miocene into the late Quaternary and Implication for Subsidence Hot-Spots

    NASA Astrophysics Data System (ADS)

    Akintomide, A. O.; Dawers, N. H.

    2017-12-01

    The observed displacement along faults in southeastern Louisiana has raised questions about the kinematic history of faults during the Quaternary. The Terrebonne Trough, a Miocene salt withdrawal basin, is bounded by the Golden Meadow fault zone on its northern boundary; north dipping, so-called counter-regional faults, together with a subsurface salt ridge, define its southern boundary. To date, there are relatively few published studies on fault architecture and kinematics in the onshore area of southeastern Louisiana. The only publically accessible studies, based on 2d seismic reflection profiles, interpreted faults as mainly striking east-west. Our interpretation of a 3-D seismic reflection volume, located in the northwestern Terrebonne Trough, as well as industry well log correlations define a more complex and highly-segmented fault architecture. The northwest striking Lake Boudreaux fault bounds a marsh on the upthrown block from Lake Boudreaux on the downthrown block. To the east, east-west striking faults are located at the Montegut marsh break and north of Isle de Jean Charles. Portions of the Lake Boudreaux and Isle de Jean Charles faults serve as the northern boundary of the Madison Bay subsidence hot-spot. All three major faults extend to the top of the 3d seismic volume, which is inferred to image latest Pleistocene stratigraphy. Well log correlation using 11+ shallow markers across these faults and kinematic techniques such as stratigraphic expansion indices indicate that all three faults were active in the middle(?) and late Pleistocene. Based on expansion indices, both the Montegut and Isle de Jean Charles faults were active simultaneously at various times, but with different slip rates. There are also time intervals when the Lake Boudreaux fault was slipping at a faster rate compared to the east-west striking faults. Smaller faults near the margins of the 3d volume appear to relate to nearby salt stocks, Bully Camp and Lake Barre. Our work to date

  19. 40 CFR 258.13 - Fault areas.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... expansions shall not be located within 200 feet (60 meters) of a fault that has had displacement in Holocene... have been displaced with respect to that on the other side. (2) Displacement means the relative...

  20. 40 CFR 258.13 - Fault areas.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... expansions shall not be located within 200 feet (60 meters) of a fault that has had displacement in Holocene... have been displaced with respect to that on the other side. (2) Displacement means the relative...

  1. 40 CFR 258.13 - Fault areas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... expansions shall not be located within 200 feet (60 meters) of a fault that has had displacement in Holocene... have been displaced with respect to that on the other side. (2) Displacement means the relative...

  2. 40 CFR 258.13 - Fault areas.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... expansions shall not be located within 200 feet (60 meters) of a fault that has had displacement in Holocene... have been displaced with respect to that on the other side. (2) Displacement means the relative...

  3. 40 CFR 258.13 - Fault areas.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... expansions shall not be located within 200 feet (60 meters) of a fault that has had displacement in Holocene... have been displaced with respect to that on the other side. (2) Displacement means the relative...

  4. Fault diagnosis for diesel valve trains based on time frequency images

    NASA Astrophysics Data System (ADS)

    Wang, Chengdong; Zhang, Youyun; Zhong, Zhenyuan

    2008-11-01

    In this paper, the Wigner-Ville distributions (WVD) of vibration acceleration signals which were acquired from the cylinder head in eight different states of valve train were calculated and displayed in grey images; and the probabilistic neural networks (PNN) were directly used to classify the time-frequency images after the images were normalized. By this way, the fault diagnosis of valve train was transferred to the classification of time-frequency images. As there is no need to extract further fault features (such as eigenvalues or symptom parameters) from time-frequency distributions before classification, the fault diagnosis process is highly simplified. The experimental results show that the faults of diesel valve trains can be classified accurately by the proposed methods.

  5. Automatic reconstruction of fault networks from seismicity catalogs: Three-dimensional optimal anisotropic dynamic clustering

    NASA Astrophysics Data System (ADS)

    Ouillon, G.; Ducorbier, C.; Sornette, D.

    2008-01-01

    We propose a new pattern recognition method that is able to reconstruct the three-dimensional structure of the active part of a fault network using the spatial location of earthquakes. The method is a generalization of the so-called dynamic clustering (or k means) method, that partitions a set of data points into clusters, using a global minimization criterion of the variance of the hypocenters locations about their center of mass. The new method improves on the original k means method by taking into account the full spatial covariance tensor of each cluster in order to partition the data set into fault-like, anisotropic clusters. Given a catalog of seismic events, the output is the optimal set of plane segments that fits the spatial structure of the data. Each plane segment is fully characterized by its location, size, and orientation. The main tunable parameter is the accuracy of the earthquake locations, which fixes the resolution, i.e., the residual variance of the fit. The resolution determines the number of fault segments needed to describe the earthquake catalog: the better the resolution, the finer the structure of the reconstructed fault segments. The algorithm successfully reconstructs the fault segments of synthetic earthquake catalogs. Applied to the real catalog constituted of a subset of the aftershock sequence of the 28 June 1992 Landers earthquake in southern California, the reconstructed plane segments fully agree with faults already known on geological maps or with blind faults that appear quite obvious in longer-term catalogs. Future improvements of the method are discussed, as well as its potential use in the multiscale study of the inner structure of fault zones.

  6. Precise relative locations for earthquakes in the northeast Pacific region

    DOE PAGES

    Cleveland, K. Michael; VanDeMark, Thomas F.; Ammon, Charles J.

    2015-10-09

    We report that double-difference methods applied to cross-correlation measured Rayleigh wave time shifts are an effective tool to improve epicentroid locations and relative origin time shifts in remote regions. We apply these methods to seismicity offshore of southwestern Canada and the U.S. Pacific Northwest, occurring along the boundaries of the Pacific and Juan de Fuca (including the Explorer Plate and Gorda Block) Plates. The Blanco, Mendocino, Revere-Dellwood, Nootka, and Sovanco fracture zones host the majority of this seismicity, largely consisting of strike-slip earthquakes. The Explorer, Juan de Fuca, and Gorda spreading ridges join these fracture zones and host normal faultingmore » earthquakes. Our results show that at least the moderate-magnitude activity clusters along fault strike, supporting suggestions of large variations in seismic coupling along oceanic transform faults. Our improved relative locations corroborate earlier interpretations of the internal deformation in the Explorer and Gorda Plates. North of the Explorer Plate, improved locations support models that propose northern extension of the Revere-Dellwood fault. Relocations also support interpretations that favor multiple parallel active faults along the Blanco Transform Fault Zone. Seismicity of the western half of the Blanco appears more scattered and less collinear than the eastern half, possibly related to fault maturity. We use azimuthal variations in the Rayleigh wave cross-correlation amplitude to detect and model rupture directivity for a moderate size earthquake along the eastern Blanco Fault. Lastly, the observations constrain the seismogenic zone geometry and suggest a relatively narrow seismogenic zone width of 2 to 4 km.« less

  7. Relationship of faults in basin sediments to the gravity and magnetic expression of their underlying fault systems

    USGS Publications Warehouse

    Baldyga, Christopher A.

    2001-01-01

    Gravity and magnetic surveys were performed along the western flanks of the Santa Rita Mountain range located in southeastern Arizona to develop an understanding of the relationship between surface fault scarps within the basin fill sediments and theirgeophysical response of the faults at depth within the bedrock. Data were acquired for three profiles, one of them along the northern terrace of Montosa Canyon, and the other two along the northern and southern terraces of Cottonwood Canyon. A total of 122 gravity stations were established as well as numerous magnetic data collected by a truckmounted cesium-vapor magnetometer. In addition, aeromagnetic data previously acquired were interpreted to obtain a geologically sound model, which produced a good fit to the data. Gravity anomalies associated with faults exhibiting surface rupture were more pronounced than the respective magnetic anomalies. More credence was given to the gravity data when determining fault structures and it was found in all three profiles that faults at depth projected through alluvium at a steeper dip than the bedrock fault indicating brittle behavior within the overlying sediments. The gravity data also detected a significant horst and graben structure within Cottonwood Canyon. The aeromagnetic data did not provide any insight into the response of the minor faults but rather served to verify the regional response of the whole profile.

  8. dc Arc Fault Effect on Hybrid ac/dc Microgrid

    NASA Astrophysics Data System (ADS)

    Fatima, Zahra

    The advent of distributed energy resources (DER) and reliability and stability problems of the conventional grid system has given rise to the wide spread deployment of microgrids. Microgrids provide many advantages by incorporating renewable energy sources and increasing the reliability of the grid by isolating from the main grid in case of an outage. AC microgrids have been installed all over the world, but dc microgrids have been gaining interest due to the advantages they provide over ac microgrids. However the entire power network backbone is still ac and dc microgrids require expensive converters to connect to the ac power network. As a result hybrid ac/dc microgrids are gaining more attention as it combines the advantages of both ac and dc microgrids such as direct integration of ac and dc systems with minimum number of conversions which increases the efficiency by reducing energy losses. Although dc electric systems offer many advantages such as no synchronization and no reactive power, successful implementation of dc systems requires appropriate protection strategies. One unique protection challenge brought by the dc systems is dc arc faults. A dc arc fault is generated when there is a gap in the conductor due to insulation degradation and current is used to bridge the gap, resulting in an arc with very high temperature. Such a fault if it goes undetected and is not extinguished can cause damage to the entire system and cause fires. The purpose of the research is to study the effect of the dc arc fault at different locations in the hybrid ac/dc microgrid and provide insight on the reliability of the grid components when it is impacted by arc faults at various locations in the grid. The impact of dc arc fault at different locations on the performance of the PV array, wind generation, and constant power loads (CPL) interfaced with dc/dc converters is studied. MATLAB/Simulink is used to model the hybrid ac/dc microgrid and arc fault.

  9. Ground Surface Deformation in Unconsolidated Sediments Caused by Bedrock Fault Movements: Dip-Slip and Strike-Slip Fault Model Test and Field Survey

    NASA Astrophysics Data System (ADS)

    Ueta, K.; Tani, K.

    2001-12-01

    shears and pressure ridges, and left-stepping and right-stepping pressure ridges are observed. d) With displacement concentrated on the central throughgoing fault zone, a "Zone of shear band" (ZSB) developed directly above the basement fault. The geometry of the ZSB shows a strong resemblance to linear ridge and trough geomorphology associated with active strike-slip faulting. (3) In the case of normal faulting, the location of the surface fault rupture is just above the bedrock faults, which have no relationship with the fault dip. On the other hand, the location of the surface rupture of the reverse fault has closely relationship with the fault dip. In the case of strike-slip faulting, the width of the deformation zone in dense sand is wider than that in loose sand. (4) The horizontal distance of surface rupture from the bedrock fault normalized by the height of sand mass (W/H) does not depend on the height of sand mass and grain size of sand. The values of W/H from the test agree well with those of earthquake faults. (5) The normalized base displacement required to propagate the shear rupture zone to the ground surface (D/H), in the case of normal faulting, is lower than those for reverse faulting and strike-slip faulting.

  10. Applying Low Temperature Thermochronology to Constrain Exhumation Patterns along the Eastern Denali Fault Corner, Alaska

    NASA Astrophysics Data System (ADS)

    Warfel, T. S.; Fitzgerald, P. G.; Benowitz, J.; Ridgway, K.; Allen, W. K.

    2017-12-01

    The Denali Fault (DF) constitutes a long ( 2000 km), arcuate, dextrally transpressive intracontinental fault system sketching across south-central Alaska. Strain-partitioning along the DF is accommodated as slip on the fault and fault-normal motion on a series of thrusts located north and south of the fault itself. High topography in the central and eastern Alaska Range, also locations of the greatest exhumation along the fault, are associated with restraining bends in those regions. East of the Richardson Highway, along the eastern Denali fault corner (or east-central segment of the DF), thrust faults south of the DF, including the McCallum thrust have accommodated the fault-normal component of motion along the DF. The aim of this project is to better understand what controls exhumation along large strike-slip faults, in particular the DF. Previous work along the DF in the central and eastern Alaska Range (to the west of this region) indicate the importance of fault geometry and rheological contrasts between terranes that have been juxtaposed against one another in controlling the location of exhumation. Our area of interest is a largely unstudied section along the Denali Fault (eastern DF corner) located between the DF/Hines Creek fault intersection and the Totschunda/DF intersection. We are applying a combination of apatite fission track thermochronology and apatite (U-Th)/He dating to samples collected north and south of the DF, and across thrust faults south of the DF. Thermochronology is being applied to bedrock samples, collected in vertical profiles and/or hanging wall - footwall pairs. Cobbles were also collected within a stratigraphic framework (constrained by tephras), from Miocene sediments in inverted basins south of the DF. Thermochronologic data from these cobbles; using lag-time analyses and inverse thermal models, will constrain the exhumation history of the hinterland. Assuming modern rates for slip along the DF will allow constraints to be placed

  11. Influence of mineralogy and microstructures on strain localization and fault zone architecture of the Alpine Fault, New Zealand

    NASA Astrophysics Data System (ADS)

    Ichiba, T.; Kaneki, S.; Hirono, T.; Oohashi, K.; Schuck, B.; Janssen, C.; Schleicher, A.; Toy, V.; Dresen, G.

    2017-12-01

    The Alpine Fault on New Zealand's South Island is an oblique, dextral strike-slip fault that accommodated the majority of displacement between the Pacific and the Australian Plates and presents the biggest seismic hazard in the region. Along its central segment, the hanging wall comprises greenschist and amphibolite facies Alpine Schists. Exhumation from 35 km depth, along a SE-dipping detachment, lead to mylonitization which was subsequently overprinted by brittle deformation and finally resulted in the fault's 1 km wide damage zone. The geomechanical behavior of a fault is affected by the internal structure of its fault zone. Consequently, studying processes controlling fault zone architecture allows assessing the seismic hazard of a fault. Here we present the results of a combined microstructural (SEM and TEM), mineralogical (XRD) and geochemical (XRF) investigation of outcrop samples originating from several locations along the Alpine Fault, the aim of which is to evaluate the influence of mineralogical composition, alteration and pre-existing fabric on strain localization and to identify the controls on the fault zone architecture, particularly the locus of brittle deformation in P, T and t space. Field observations reveal that the fault's principal slip zone (PSZ) is either a thin (< 1 cm to < 7 cm) layered structure or a relatively thick (10s cm) package lacking a detectable macroscopic fabric. Lithological and related rheological contrasts are widely assumed to govern strain localization. However, our preliminary results suggest that qualitative mineralogical composition has only minor impact on fault zone architecture. Quantities of individual mineral phases differ markedly between fault damage zone and fault core at specific sites, but the quantitative composition of identical structural units such as the fault core, is similar in all samples. This indicates that the degree of strain localization at the Alpine Fault might be controlled by small initial

  12. Implementation of Integrated System Fault Management Capability

    NASA Technical Reports Server (NTRS)

    Figueroa, Fernando; Schmalzel, John; Morris, Jon; Smith, Harvey; Turowski, Mark

    2008-01-01

    Fault Management to support rocket engine test mission with highly reliable and accurate measurements; while improving availability and lifecycle costs. CORE ELEMENTS: Architecture, taxonomy, and ontology (ATO) for DIaK management. Intelligent Sensor Processes; Intelligent Element Processes; Intelligent Controllers; Intelligent Subsystem Processes; Intelligent System Processes; Intelligent Component Processes.

  13. 5000 yr of paleoseismicity along the southern Dead Sea fault

    NASA Astrophysics Data System (ADS)

    Klinger, Y.; Le Béon, M.; Al-Qaryouti, M.

    2015-07-01

    The 1000-km-long left-lateral Dead Sea fault is a major tectonic structure of the oriental Mediterranean basin, bounding the Arabian Plate to the west. The fault is located in a region with an exceptionally long and rich historical record, allowing to document historical seismicity catalogues with unprecedented level of details. However, if the earthquake time series is well documented, location and lateral extent of past earthquakes remain often difficult to establish, if only based on historical testimonies. We excavated a palaeoseismic trench in a site located in a kilometre-size extensional jog, south of the Dead Sea, in the Wadi Araba. Based on the stratigraphy exposed in the trench, we present evidence for nine earthquakes that produced surface ruptures during a time period spanning 5000 yr. Abundance of datable material allows us to tie the five most recent events to historical earthquakes with little ambiguities, and to constrain the possible location of these historical earthquakes. The events identified at our site are the 1458 C.E., 1212 C.E., 1068 C.E., one event during the 8th century crisis, and the 363 C.E. earthquake. Four other events are also identified, which correlation with historical events remains more speculative. The magnitude of earthquakes is difficult to assess based on evidence at one site only. The deformation observed in the excavation, however, allows discriminating between two classes of events that produced vertical deformation with one order of amplitude difference, suggesting that we could distinguish earthquakes that started/stopped at our site from earthquakes that potentially ruptured most of the Wadi Araba fault. The time distribution of earthquakes during the past 5000 yr is uneven. The early period shows little activity with return interval of ˜500 yr or longer. It is followed by a ˜1500-yr-long period with more frequent events, about every 200 yr. Then, for the past ˜550 yr, the fault has switched back to a quieter mode

  14. Multiple incipient sensor faults diagnosis with application to high-speed railway traction devices.

    PubMed

    Wu, Yunkai; Jiang, Bin; Lu, Ningyun; Yang, Hao; Zhou, Yang

    2017-03-01

    This paper deals with the problem of incipient fault diagnosis for a class of Lipschitz nonlinear systems with sensor biases and explores further results of total measurable fault information residual (ToMFIR). Firstly, state and output transformations are introduced to transform the original system into two subsystems. The first subsystem is subject to system disturbances and free from sensor faults, while the second subsystem contains sensor faults but without any system disturbances. Sensor faults in the second subsystem are then formed as actuator faults by using a pseudo-actuator based approach. Since the effects of system disturbances on the residual are completely decoupled, multiple incipient sensor faults can be detected by constructing ToMFIR, and the fault detectability condition is then derived for discriminating the detectable incipient sensor faults. Further, a sliding-mode observers (SMOs) based fault isolation scheme is designed to guarantee accurate isolation of multiple sensor faults. Finally, simulation results conducted on a CRH2 high-speed railway traction device are given to demonstrate the effectiveness of the proposed approach. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  15. Fault tectonics and earthquake hazards in parts of southern California. [penninsular ranges, Garlock fault, Salton Trough area, and western Mojave Desert

    NASA Technical Reports Server (NTRS)

    Merifield, P. M. (Principal Investigator); Lamar, D. L.; Gazley, C., Jr.; Lamar, J. V.; Stratton, R. H.

    1976-01-01

    The author has identified the following significant results. Four previously unknown faults were discovered in basement terrane of the Peninsular Ranges. These have been named the San Ysidro Creek fault, Thing Valley fault, Canyon City fault, and Warren Canyon fault. In addition fault gouge and breccia were recognized along the San Diego River fault. Study of features on Skylab imagery and review of geologic and seismic data suggest that the risk of a damaging earthquake is greater along the northwestern portion of the Elsinore fault than along the southeastern portion. Physiographic indicators of active faulting along the Garlock fault identifiable in Skylab imagery include scarps, linear ridges, shutter ridges, faceted ridges, linear valleys, undrained depressions and offset drainage. The following previously unrecognized fault segments are postulated for the Salton Trough Area: (1) An extension of a previously known fault in the San Andreas fault set located southeast of the Salton Sea; (2) An extension of the active San Jacinto fault zone along a tonal change in cultivated fields across Mexicali Valley ( the tonal change may represent different soil conditions along opposite sides of a fault). For the Skylab and LANDSAT images studied, pseudocolor transformations offer no advantages over the original images in the recognition of faults in Skylab and LANDSAT images. Alluvial deposits of different ages, a marble unit and iron oxide gossans of the Mojave Mining District are more readily differentiated on images prepared from ratios of individual bands of the S-192 multispectral scanner data. The San Andreas fault was also made more distinct in the 8/2 and 9/2 band ratios by enhancement of vegetation differences on opposite sides of the fault. Preliminary analysis indicates a significant earth resources potential for the discrimination of soil and rock types, including mineral alteration zones. This application should be actively pursued.

  16. Gravity and Magnetic Surveys Over the Santa Rita Fault System, Southeastern Arizona

    USGS Publications Warehouse

    Hegmann, Mary

    2001-01-01

    Gravity and magnetic surveys were performed in the northeast portion of the Santa Rita Experimental Range, in southeastern Arizona, to identify faults and gain a better understanding of the subsurface geology. A total of 234 gravity stations were established, and numerous magnetic data were collected with portable and truck-mounted proton precession magnetometers. In addition, one line of very low frequency electromagnetic data was collected together with magnetic data. Gravity anomalies are used to identify two normal faults that project northward toward a previously identified fault. The gravity data also confirm the location of a second previously interpreted normal fault. Interpretation of magnetic anomaly data indicates the presence of a higher-susceptibility sedimentary unit located beneath lowersusceptibility surficial sediments. Magnetic anomaly data identify a 1-km-wide negative anomaly east of these faults caused by an unknown source and reveal the high variability of susceptibility in the Tertiary intrusive rocks in the area.

  17. Fault healing and earthquake spectra from stick slip sequences in the laboratory and on active faults

    NASA Astrophysics Data System (ADS)

    McLaskey, G. C.; Glaser, S. D.; Thomas, A.; Burgmann, R.

    2011-12-01

    Repeating earthquake sequences (RES) are thought to occur on isolated patches of a fault that fail in repeated stick-slip fashion. RES enable researchers to study the effect of variations in earthquake recurrence time and the relationship between fault healing and earthquake generation. Fault healing is thought to be the physical process responsible for the 'state' variable in widely used rate- and state-dependent friction equations. We analyze RES created in laboratory stick slip experiments on a direct shear apparatus instrumented with an array of very high frequency (1KHz - 1MHz) displacement sensors. Tests are conducted on the model material polymethylmethacrylate (PMMA). While frictional properties of this glassy polymer can be characterized with the rate- and state- dependent friction laws, the rate of healing in PMMA is higher than room temperature rock. Our experiments show that in addition to a modest increase in fault strength and stress drop with increasing healing time, there are distinct spectral changes in the recorded laboratory earthquakes. Using the impact of a tiny sphere on the surface of the test specimen as a known source calibration function, we are able to remove the instrument and apparatus response from recorded signals so that the source spectrum of the laboratory earthquakes can be accurately estimated. The rupture of a fault that was allowed to heal produces a laboratory earthquake with increased high frequency content compared to one produced by a fault which has had less time to heal. These laboratory results are supported by observations of RES on the Calaveras and San Andreas faults, which show similar spectral changes when recurrence time is perturbed by a nearby large earthquake. Healing is typically attributed to a creep-like relaxation of the material which causes the true area of contact of interacting asperity populations to increase with time in a quasi-logarithmic way. The increase in high frequency seismicity shown here

  18. Electrical conductivity of a locked fault: investigation of the Ganos segment of the North Anatolian Fault using three-dimensional magnetotellurics

    NASA Astrophysics Data System (ADS)

    Karaş, Mustafa; Tank, Sabri Bülent; Özaydın, Sinan

    2017-08-01

    This study attempts to reveal the fault zone characteristics of the locked Ganos Fault based on electrical resistivity studies including audio-frequency (AMT: 10,400-1 Hz) and wide-band (MT: 360-0.000538 Hz) magnetotellurics near the epicenter of the last major event, that is, the 1912 Mürefte Earthquake ( M w 7.4). The AMT data were collected at twelve stations, closely spaced from north to south, to resolve the shallow resistivity structure to 1 km depth. Subsequently, 13 wide-band MT stations were arranged to form a grid enclosing the AMT profile to decipher the deeper structure. Three-dimensional inverse modeling indicates highly conductive anomalies representing fault zone conductors along the Ganos Fault. Subsidiary faults around the Ganos Fault, which are conductive structures with individual mechanically weak features, merge into a greater damage zone, creating a wide fluid-bearing environment. This damage zone is located on the southern side of the fault and defines an asymmetry around the main fault strand, which demonstrates distributed conduit behavior of fluid flow. Ophiolitic basement occurs as low-conductivity block beneath younger formations at a depth of 2 km, where the mechanically weak to strong transition occurs. Resistive structures on both sides of the fault beneath this transition suggest that the lack of seismicity might be related to the absence of fluid pathways in the seismogenic zone.[Figure not available: see fulltext.

  19. The relationship between oceanic transform fault segmentation, seismicity, and thermal structure

    NASA Astrophysics Data System (ADS)

    Wolfson-Schwehr, Monica

    analysis is used to model 3-D RTF fault geometry assuming a viscoplastic rheology in order to determine how segmentation affects the underlying thermal structure of the fault. In the models, fault segment length, length and location along fault of the intra-transform spreading center, and slip rate are varied. A new scaling relation is developed for the critical fault offset length (OC) that significantly reduces the thermal area of adjacent fault segments, such that adjacent segments are fully decoupled at ~4 OC . On moderate to fast slipping RTFs, offsets ≥ 5 km are sufficient to significantly reduce the thermal influence between two adjacent transform fault segments. The relationship between fault structure and seismic behavior was directly addressed on the Discovery transform fault, located at 4°S on the East Pacific Rise. One year of microseismicity recorded on an OBS array, and 24 years of Mw ≥ 5.4 earthquakes obtained from the Global Centroid Moment Tensor catalog, were correlated with surface fault structure delineated from high-resolution multibeam bathymetry. Each of the 15 Mw ≥ 5.4 earthquakes was relocated into one of five distinct repeating rupture patches, while microseismicity was found to be reduced within these patches. While the endpoints of these patches appeared to correlate with structural features on the western segment of Discovery, small step-overs in the primary fault trace were not observed at patch boundaries. This indicates that physical segmentation of the fault is not the primary control on the size and location of large earthquakes on Discovery, and that along-strike heterogeneity in fault zone properties must play an important role.

  20. Fault model of the 2017 Jiuzhaigou Mw 6.5 earthquake estimated from coseismic deformation observed using Global Positioning System and Interferometric Synthetic Aperture Radar data

    NASA Astrophysics Data System (ADS)

    Nie, Zhaosheng; Wang, Di-Jin; Jia, Zhige; Yu, Pengfei; Li, Liangfa

    2018-04-01

    On August 8, 2017, the Jiuzhaigou Mw 6.5 earthquake occurred in Sichuan province, southwestern China, along the eastern margin of the Tibetan Plateau. The epicenter is surrounded by the Minjiang, Huya, and Tazang Faults. As the seismic activity and tectonics are very complicated, there is controversy regarding the accurate location of the epicenter and the seismic fault of the Jiuzhaigou earthquake. To investigate these aspects, first, the coseismic deformation field was derived from Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) measurements. Second, the fault geometry, coseismic slip model, and Coulomb stress changes around the seismic region were calculated using a homogeneous elastic half-space model. The coseismic deformation field derived from InSAR measurements shows that this event was mainly dominated by a left-lateral strike-slip fault. The maximal and minimal displacements were approximately 0.15 m and - 0.21 m, respectively, along line-of-sight observation. The whole deformation field follows a northwest-trending direction and is mainly concentrated west of the fault. The coseismic slip is 28 km along the strike and 18 km along the dip. It is dominated by a left-lateral strike-slip fault. The average and maximal fault slip is 0.18 and 0.85 m, respectively. The rupture did not fully reach the ground surface. The focal mechanism derived from GPS and InSAR data is consistent with the kinematics and geometry of the Huya Fault. Therefore, we conclude that the northern section or the Shuzheng segment of the Huya Fault is the seismogenic fault. The maximal fault slip is located at 33.25°N and 103.82°E at a depth of 11 km, and the release moment is approximately 6.635 × 1018 Nm, corresponding to a magnitude of Mw 6.49, which is consistent with results reported by the US Geological Survey, Global Centroid Moment Tensor, and other researchers. The coseismic Coulomb stress changes enhanced the stress on the northwest and

  1. Precise Hypocenter Determination around Palu Koro Fault: a Preliminary Results

    NASA Astrophysics Data System (ADS)

    Fawzy Ismullah, M. Muhammad; Nugraha, Andri Dian; Ramdhan, Mohamad; Wandono

    2017-04-01

    Sulawesi area is located in complex tectonic pattern. High seismicity activity in the middle of Sulawesi is related to Palu Koro fault (PKF). In this study, we determined precise hypocenter around PKF by applying double-difference method. We attempt to investigate of the seismicity rate, geometry of the fault and distribution of focus depth around PKF. We first re-pick P-and S-wave arrival time of the PKF events to determine the initial hypocenter location using Hypoellipse method through updated 1-D seismic velocity. Later on, we relocated the earthquake event using double-difference method. Our preliminary results show the distribution of relocated events are located around PKF and have smaller residual time than the initial location. We will enhance the hypocenter location through updating of arrival time by applying waveform cross correlation method as input for double-difference relocation.

  2. A PC based time domain reflectometer for space station cable fault isolation

    NASA Technical Reports Server (NTRS)

    Pham, Michael; McClean, Marty; Hossain, Sabbir; Vo, Peter; Kouns, Ken

    1994-01-01

    Significant problems are faced by astronauts on orbit in the Space Station when trying to locate electrical faults in multi-segment avionics and communication cables. These problems necessitate the development of an automated portable device that will detect and locate cable faults using the pulse-echo technique known as Time Domain Reflectometry. A breadboard time domain reflectometer (TDR) circuit board was designed and developed at the NASA-JSC. The TDR board works in conjunction with a GRiD lap-top computer to automate the fault detection and isolation process. A software program was written to automatically display the nature and location of any possible faults. The breadboard system can isolate open circuit and short circuit faults within two feet in a typical space station cable configuration. Follow-on efforts planned for 1994 will produce a compact, portable prototype Space Station TDR capable of automated switching in multi-conductor cables for high fidelity evaluation. This device has many possible commercial applications, including commercial and military aircraft avionics, cable TV, telephone, communication, information and computer network systems. This paper describes the principle of time domain reflectometry and the methodology for on-orbit avionics utility distribution system repair, utilizing the newly developed device called the Space Station Time Domain Reflectometer (SSTDR).

  3. 3D Dynamic Rupture Simulations along Dipping Faults, with a focus on the Wasatch Fault Zone, Utah

    NASA Astrophysics Data System (ADS)

    Withers, K.; Moschetti, M. P.

    2017-12-01

    We study dynamic rupture and ground motion from dip-slip faults in regions that have high-seismic hazard, such as the Wasatch fault zone, Utah. Previous numerical simulations have modeled deterministic ground motion along segments of this fault in the heavily populated regions near Salt Lake City but were restricted to low frequencies ( 1 Hz). We seek to better understand the rupture process and assess broadband ground motions and variability from the Wasatch Fault Zone by extending deterministic ground motion prediction to higher frequencies (up to 5 Hz). We perform simulations along a dipping normal fault (40 x 20 km along strike and width, respectively) with characteristics derived from geologic observations to generate a suite of ruptures > Mw 6.5. This approach utilizes dynamic simulations (fully physics-based models, where the initial stress drop and friction law are imposed) using a summation by parts (SBP) method. The simulations include rough-fault topography following a self-similar fractal distribution (over length scales from 100 m to the size of the fault) in addition to off-fault plasticity. Energy losses from heat and other mechanisms, modeled as anelastic attenuation, are also included, as well as free-surface topography, which can significantly affect ground motion patterns. We compare the effect of material structure and both rate and state and slip-weakening friction laws have on rupture propagation. The simulations show reduced slip and moment release in the near surface with the inclusion of plasticity, better agreeing with observations of shallow slip deficit. Long-wavelength fault geometry imparts a non-uniform stress distribution along both dip and strike, influencing the preferred rupture direction and hypocenter location, potentially important for seismic hazard estimation.

  4. The Active Fault Parameters for Time-Dependent Earthquake Hazard Assessment in Taiwan

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Cheng, C.; Lin, P.; Shao, K.; Wu, Y.; Shih, C.

    2011-12-01

    Taiwan is located at the boundary between the Philippine Sea Plate and the Eurasian Plate, with a convergence rate of ~ 80 mm/yr in a ~N118E direction. The plate motion is so active that earthquake is very frequent. In the Taiwan area, disaster-inducing earthquakes often result from active faults. For this reason, it's an important subject to understand the activity and hazard of active faults. The active faults in Taiwan are mainly located in the Western Foothills and the Eastern longitudinal valley. Active fault distribution map published by the Central Geological Survey (CGS) in 2010 shows that there are 31 active faults in the island of Taiwan and some of which are related to earthquake. Many researchers have investigated these active faults and continuously update new data and results, but few people have integrated them for time-dependent earthquake hazard assessment. In this study, we want to gather previous researches and field work results and then integrate these data as an active fault parameters table for time-dependent earthquake hazard assessment. We are going to gather the seismic profiles or earthquake relocation of a fault and then combine the fault trace on land to establish the 3D fault geometry model in GIS system. We collect the researches of fault source scaling in Taiwan and estimate the maximum magnitude from fault length or fault area. We use the characteristic earthquake model to evaluate the active fault earthquake recurrence interval. In the other parameters, we will collect previous studies or historical references and complete our parameter table of active faults in Taiwan. The WG08 have done the time-dependent earthquake hazard assessment of active faults in California. They established the fault models, deformation models, earthquake rate models, and probability models and then compute the probability of faults in California. Following these steps, we have the preliminary evaluated probability of earthquake-related hazards in certain

  5. Interacting faults

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.; Nixon, C. W.; Rotevatn, A.; Sanderson, D. J.; Zuluaga, L. F.

    2017-04-01

    The way that faults interact with each other controls fault geometries, displacements and strains. Faults rarely occur individually but as sets or networks, with the arrangement of these faults producing a variety of different fault interactions. Fault interactions are characterised in terms of the following: 1) Geometry - the spatial arrangement of the faults. Interacting faults may or may not be geometrically linked (i.e. physically connected), when fault planes share an intersection line. 2) Kinematics - the displacement distributions of the interacting faults and whether the displacement directions are parallel, perpendicular or oblique to the intersection line. Interacting faults may or may not be kinematically linked, where the displacements, stresses and strains of one fault influences those of the other. 3) Displacement and strain in the interaction zone - whether the faults have the same or opposite displacement directions, and if extension or contraction dominates in the acute bisector between the faults. 4) Chronology - the relative ages of the faults. This characterisation scheme is used to suggest a classification for interacting faults. Different types of interaction are illustrated using metre-scale faults from the Mesozoic rocks of Somerset and examples from the literature.

  6. Fiber Bragg grating sensor for fault detection in high voltage overhead transmission lines

    NASA Astrophysics Data System (ADS)

    Moghadas, Amin

    2011-12-01

    A fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by fiber Bragg grating (FBG) sensors. The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signals. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN) algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG sensors and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system.

  7. Fiber Bragg Grating Sensor for Fault Detection in Radial and Network Transmission Lines

    PubMed Central

    Moghadas, Amin A.; Shadaram, Mehdi

    2010-01-01

    In this paper, a fiber optic based sensor capable of fault detection in both radial and network overhead transmission power line systems is investigated. Bragg wavelength shift is used to measure the fault current and detect fault in power systems. Magnetic fields generated by currents in the overhead transmission lines cause a strain in magnetostrictive material which is then detected by Fiber Bragg Grating (FBG). The Fiber Bragg interrogator senses the reflected FBG signals, and the Bragg wavelength shift is calculated and the signals are processed. A broadband light source in the control room scans the shift in the reflected signal. Any surge in the magnetic field relates to an increased fault current at a certain location. Also, fault location can be precisely defined with an artificial neural network (ANN) algorithm. This algorithm can be easily coordinated with other protective devices. It is shown that the faults in the overhead transmission line cause a detectable wavelength shift on the reflected signal of FBG and can be used to detect and classify different kind of faults. The proposed method has been extensively tested by simulation and results confirm that the proposed scheme is able to detect different kinds of fault in both radial and network system. PMID:22163416

  8. Off-fault plasticity in three-dimensional dynamic rupture simulations using a modal Discontinuous Galerkin method on unstructured meshes: Implementation, verification, and application

    NASA Astrophysics Data System (ADS)

    Wollherr, Stephanie; Gabriel, Alice-Agnes; Uphoff, Carsten

    2018-05-01

    The dynamics and potential size of earthquakes depend crucially on rupture transfers between adjacent fault segments. To accurately describe earthquake source dynamics, numerical models can account for realistic fault geometries and rheologies such as nonlinear inelastic processes off the slip interface. We present implementation, verification, and application of off-fault Drucker-Prager plasticity in the open source software SeisSol (www.seissol.org). SeisSol is based on an arbitrary high-order derivative modal Discontinuous Galerkin (ADER-DG) method using unstructured, tetrahedral meshes specifically suited for complex geometries. Two implementation approaches are detailed, modelling plastic failure either employing sub-elemental quadrature points or switching to nodal basis coefficients. At fine fault discretizations the nodal basis approach is up to 6 times more efficient in terms of computational costs while yielding comparable accuracy. Both methods are verified in community benchmark problems and by three dimensional numerical h- and p-refinement studies with heterogeneous initial stresses. We observe no spectral convergence for on-fault quantities with respect to a given reference solution, but rather discuss a limitation to low-order convergence for heterogeneous 3D dynamic rupture problems. For simulations including plasticity, a high fault resolution may be less crucial than commonly assumed, due to the regularization of peak slip rate and an increase of the minimum cohesive zone width. In large-scale dynamic rupture simulations based on the 1992 Landers earthquake, we observe high rupture complexity including reverse slip, direct branching, and dynamic triggering. The spatio-temporal distribution of rupture transfers are altered distinctively by plastic energy absorption, correlated with locations of geometrical fault complexity. Computational cost increases by 7% when accounting for off-fault plasticity in the demonstrating application. Our results

  9. Fault recovery characteristics of the fault tolerant multi-processor

    NASA Technical Reports Server (NTRS)

    Padilla, Peter A.

    1990-01-01

    The fault handling performance of the fault tolerant multiprocessor (FTMP) was investigated. Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles byzantine or lying faults. It is pointed out that these weak areas in the FTMP's design increase the probability that, for any hardware fault, a good LRU (line replaceable unit) is mistakenly disabled by the fault management software. It is concluded that fault injection can help detect and analyze the behavior of a system in the ultra-reliable regime. Although fault injection testing cannot be exhaustive, it has been demonstrated that it provides a unique capability to unmask problems and to characterize the behavior of a fault-tolerant system.

  10. Delineation of fault zones using imaging radar

    NASA Technical Reports Server (NTRS)

    Toksoz, M. N.; Gulen, L.; Prange, M.; Matarese, J.; Pettengill, G. H.; Ford, P. G.

    1986-01-01

    The assessment of earthquake hazards and mineral and oil potential of a given region requires a detailed knowledge of geological structure, including the configuration of faults. Delineation of faults is traditionally based on three types of data: (1) seismicity data, which shows the location and magnitude of earthquake activity; (2) field mapping, which in remote areas is typically incomplete and of insufficient accuracy; and (3) remote sensing, including LANDSAT images and high altitude photography. Recently, high resolution radar images of tectonically active regions have been obtained by SEASAT and Shuttle Imaging Radar (SIR-A and SIR-B) systems. These radar images are sensitive to terrain slope variations and emphasize the topographic signatures of fault zones. Techniques were developed for using the radar data in conjunction with the traditional types of data to delineate major faults in well-known test sites, and to extend interpretation techniques to remote areas.

  11. Unsaturated flow and transport through a fault embedded in fractured welded tuff

    USGS Publications Warehouse

    Salve, Rohit; Liu, Hui‐Hai; Cook, Paul; Czarnomski, Atlantis; Hu, Qinhong; Hudson, David

    2004-01-01

    To evaluate the importance of matrix diffusion as a mechanism for retarding radionuclide transport in the vicinity of a fault located in unsaturated fractured rock, we carried out an in situ field experiment in the Exploratory Studies Facility at Yucca Mountain, Nevada. This experiment involved the release of ∼82,000 L of water over a period of 17 months directly into a near‐vertical fault under both constant positive head (at ∼0.04 m) and decreasing fluxes. A mix of conservative tracers (pentafluorobenzoic acid (PFBA) and bromide (applied in the form of lithium bromide)) was released along the fault over a period of 9 days, 7 months after the start of water release along the fault. As water was released into the fault, seepage rates were monitored in a large cavity excavated below the test bed. After the release of tracers, seepage water was continuously collected from three locations and analyzed for the injected tracers. Observations of bromide concentrations in seepage water during the early stages of the experiment and bromide and PFBA concentrations in the seepage water indicate the significant effects of matrix diffusion on transport through a fault embedded in fractured, welded rock.

  12. Recent deformation on the San Diego Trough and San Pedro Basin fault systems, offshore Southern California: Assessing evidence for fault system connectivity.

    NASA Astrophysics Data System (ADS)

    Bormann, J. M.; Kent, G. M.; Driscoll, N. W.; Harding, A. J.

    2016-12-01

    The seismic hazard posed by offshore faults for coastal communities in Southern California is poorly understood and may be considerable, especially when these communities are located near long faults that have the ability to produce large earthquakes. The San Diego Trough fault (SDTF) and San Pedro Basin fault (SPBF) systems are active northwest striking, right-lateral faults in the Inner California Borderland that extend offshore between San Diego and Los Angeles. Recent work shows that the SDTF slip rate accounts for 25% of the 6-8 mm/yr of deformation accommodated by the offshore fault network, and seismic reflection data suggest that these two fault zones may be one continuous structure. Here, we use recently acquired CHIRP, high-resolution multichannel seismic (MCS) reflection, and multibeam bathymetric data in combination with USGS and industry MCS profiles to characterize recent deformation on the SDTF and SPBF zones and to evaluate the potential for an end-to-end rupture that spans both fault systems. The SDTF offsets young sediments at the seafloor for 130 km between the US/Mexico border and Avalon Knoll. The northern SPBF has robust geomorphic expression and offsets the seafloor in the Santa Monica Basin. The southern SPBF lies within a 25-km gap between high-resolution MCS surveys. Although there does appear to be a through-going fault at depth in industry MCS profiles, the low vertical resolution of these data inhibits our ability to confirm recent slip on the southern SPBF. Empirical scaling relationships indicate that a 200-km-long rupture of the SDTF and its southern extension, the Bahia Soledad fault, could produce a M7.7 earthquake. If the SDTF and the SPBF are linked, the length of the combined fault increases to >270 km. This may allow ruptures initiating on the SDTF to propagate within 25 km of the Los Angeles Basin. At present, the paleoseismic histories of the faults are unknown. We present new observations from CHIRP and coring surveys at

  13. Fluid-faulting interactions: Fracture-mesh and fault-valve behavior in the February 2014 Mammoth Mountain, California, earthquake swarm

    USGS Publications Warehouse

    Shelly, David R.; Taira, Taka’aki; Prejean, Stephanie; Hill, David P.; Dreger, Douglas S.

    2015-01-01

    Faulting and fluid transport in the subsurface are highly coupled processes, which may manifest seismically as earthquake swarms. A swarm in February 2014 beneath densely monitored Mammoth Mountain, California, provides an opportunity to witness these interactions in high resolution. Toward this goal, we employ massive waveform-correlation-based event detection and relative relocation, which quadruples the swarm catalog to more than 6000 earthquakes and produces high-precision locations even for very small events. The swarm's main seismic zone forms a distributed fracture mesh, with individual faults activated in short earthquake bursts. The largest event of the sequence, M 3.1, apparently acted as a fault valve and was followed by a distinct wave of earthquakes propagating ~1 km westward from the updip edge of rupture, 1–2 h later. Late in the swarm, multiple small, shallower subsidiary faults activated with pronounced hypocenter migration, suggesting that a broader fluid pressure pulse propagated through the subsurface.

  14. Subsurface structure identification of active fault based on magnetic anomaly data (Case study: Toru fault in Sumatera fault system)

    NASA Astrophysics Data System (ADS)

    Simanjuntak, Andrean V. H.; Husni, Muhammad; Syirojudin, Muhammad

    2017-07-01

    Toru segment, which is one of the active faults and located in the North of Sumatra, broke in 1984 ago on Pahae Jahe's earthquake with a magnitude 6.4 at the northern part of the fault which has a length of 23 km, and also broke again at the same place in 2008. The event of recurrence is very fast, which only 25 years old have repeatedly returned. However, in the elastic rebound theory, it probably happen with a fracture 50 cm and an average of the shear velocity 20 mm/year. The average focus of the earthquake sourced at a depth of 10 km and 23 km along its fracture zones, which can generate enough shaking 7 MMI and could breaking down buildings and create landslides on the cliff. Due to its seismic activity, this study was made to identify the effectiveness of this fault with geophysical methods. Geophysical methods such as gravity, geomagnetic and seismology are powerful tools for detecting subsurface structures of local, regional as well as of global scales. This study used to geophysical methods to discuss about total intensity of the geomagnetic anomaly data, resulted in the distribution of susceptibility values corresponding to the fault movement. The geomagnetic anomalies data was obtained from Geomag, such as total intensity measured by satellite. Data acquisition have been corrected for diurnal variations and reduced by IGRF. The study of earthquake records can be used for differentiating the active and non active fault elements. Modeling has been done using several methods, such as pseudo-gravity, reduce to pole, and upward or downward continuation, which is used to filter the geomagnetic anomaly data because the data has not fully representative of the fault structure. The results indicate that rock layers of 0 - 100 km depth encountered the process of intrusion and are dominated by sedimentary rocks that are paramagnetic, and that the ones of 100 - 150 km depth experienced the activity of subducting slab consisting of basalt and granite which are

  15. A High-Resolution Seismic Survey Across the State Line fault, NV

    NASA Astrophysics Data System (ADS)

    Beachly, M.; Cox, C. M.; Saldana, S. C.; Snelson, C. M.; Taylor, W. J.; Robins, C.; Davis, R.; Stropky, M.; Phillips, R.; Cothrun, C.

    2007-12-01

    During the summer of 2007, an investigation of the faulting in Stewart Valley was under taken, located within the central Basin and Range province ~90 km west of Las Vegas, Nevada. The goal of this study was to resolve the seismic hazard potential of the State Line fault, a right-lateral strike-slip fault that runs the length of Stewart Valley. Four seismic reflection lines were acquired, two perpendicular and two parallel to the State Line fault. What is presented is an analysis of the western and eastern seismic lines parallel to the State Line fault. The western line was acquired utilizing a 144-channel geode system with each of the 4.5 Hz vertical geophones set out at 5 m intervals to form a 715 m long profile. The eastern line employed 120 of these geophones in a 595 m long profile. A mini-vibroseis served as the seismic source every ten meters, between geophones. The vibroseis was programmed to produce an 8 s linear sweep from 20-160 Hz. Three sweeps were recorded at each shot location without acquisition filters at a sampling rate of 0.5 ms. The three shot gathers were then stacked at each location to reduce noise. The data collected had minimal noise, although; during the processing of the eastern line a notch filtered was used to remove the 60 Hz noise created by adjacent power line. These lines, acquired parallel to the State Line fault, contain matching features that serve to determine how much lateral displacement the fault has undergone. The amount of the displacement can indicate how active the fault is, and thus, what magnitude of earthquake can be expected in the future. This will in turn contribute to determining the seismic hazard potential for southern Nevada. A preliminary interpretation of the seismic reflection sections indicates an average displacement of about 20 - 38 m with greater displacement in the deeper sections of the image. The shallow depth displacement calculations are consistent with previous work in the area. The State Line fault

  16. Faults in parts of north-central and western Houston metropolitan area, Texas

    USGS Publications Warehouse

    Verbeek, Earl R.; Ratzlaff, Karl W.; Clanton, Uel S.

    1979-01-01

    Hundreds of residential, commercial, and industrial structures in the Houston metropolitan area have sustained moderate to severe damage owing to their locations on or near active faults. Paved roads have been offset by faults at hundreds of locations, butted pipelines have been distorted by fault movements, and fault-induced gradient changes in drainage lines have raised concern among flood control engineers. Over 150 faults, many of them moving at rates of 0.5 to 2 cm/yr, have been mapped in the Houston area; the number of faults probably far exceeds this figure.This report includes a map of eight faults, in north-central and western Houston, at a scale useful for land-use planning. Seven of the faults, are known, to be active and have caused considerable damage to structures built on or near them. If the eighth fault is active, it may be of concern to new developments on the west side of Houston. A ninth feature shown on the map is regarded only as a possible fault, as an origin by faulting has not been firmly established.Seismic and drill-hold data for some 40 faults, studied in detail by various investigators have verified connections between scarps at the land surface and growth faults in the shallow subsurface. Some scarps, then, are known to be the surface manifestations of faults that have geologically long histories of movement. The degree to which natural geologic processes contribute to current fault movement, however, is unclear, for some of man’s activities may play a role in faulting as well.Evidence that current rates of fault movement far exceed average prehistoric rates and that most offset of the land surface in the Houston area has occurred only within the last 50 years indirectly suggest that fluid withdrawal may be accelerating or reinitiating movement on pre-existing faults. This conclusion, however, is based only on a coincidence in time between increased fault activity and increased rates of withdrawal of water, oil, and gas from

  17. Evidence for faulting related to dissociation of gas hydrate and release of methane off the southeastern United States

    USGS Publications Warehouse

    Dillon, William P.; Danforth, W.W.; Hutchinson, D.R.; Drury, R.M.; Taylor, M.H.; Booth, J.S.

    1998-01-01

    This paper is part of the special publication Gas hydrates: relevance to world margin stability and climatic change (eds J.P. Henriet and J. Mienert). An irregular, faulted, collapse depression about 38 x 18 km in extent is located on the crest of the Blake Ridge offshore from the south- eastern United States. Faults disrupt the sea floor and terminate or sole out about 40-500 m below the sea floor at the base of the gas hydrate stable zone, which is identified from the location of the bottom simulating reflection (BSR). Normal faults are common but reverse faults and folds also are widespread. Folds commonly convert upward into faults. Sediment diapirs and deposits of sediments that were erupted onto the sea floor are also present. Sea-floor depressions at faults may represent locations of liquid/gas vents. The collapse was probably caused by overpressures and by the decoupling of the overlying sediments by gassy muds that existed just beneath the zone of gas hydrate stability.

  18. Methods to enhance seismic faults and construct fault surfaces

    NASA Astrophysics Data System (ADS)

    Wu, Xinming; Zhu, Zhihui

    2017-10-01

    Faults are often apparent as reflector discontinuities in a seismic volume. Numerous types of fault attributes have been proposed to highlight fault positions from a seismic volume by measuring reflection discontinuities. These attribute volumes, however, can be sensitive to noise and stratigraphic features that are also apparent as discontinuities in a seismic volume. We propose a matched filtering method to enhance a precomputed fault attribute volume, and simultaneously estimate fault strikes and dips. In this method, a set of efficient 2D exponential filters, oriented by all possible combinations of strike and dip angles, are applied to the input attribute volume to find the maximum filtering responses at all samples in the volume. These maximum filtering responses are recorded to obtain the enhanced fault attribute volume while the corresponding strike and dip angles, that yield the maximum filtering responses, are recoded to obtain volumes of fault strikes and dips. By doing this, we assume that a fault surface is locally planar, and a 2D smoothing filter will yield a maximum response if the smoothing plane coincides with a local fault plane. With the enhanced fault attribute volume and the estimated fault strike and dip volumes, we then compute oriented fault samples on the ridges of the enhanced fault attribute volume, and each sample is oriented by the estimated fault strike and dip. Fault surfaces can be constructed by directly linking the oriented fault samples with consistent fault strikes and dips. For complicated cases with missing fault samples and noisy samples, we further propose to use a perceptual grouping method to infer fault surfaces that reasonably fit the positions and orientations of the fault samples. We apply these methods to 3D synthetic and real examples and successfully extract multiple intersecting fault surfaces and complete fault surfaces without holes.

  19. Abnormal fault-recovery characteristics of the fault-tolerant multiprocessor uncovered using a new fault-injection methodology

    NASA Technical Reports Server (NTRS)

    Padilla, Peter A.

    1991-01-01

    An investigation was made in AIRLAB of the fault handling performance of the Fault Tolerant MultiProcessor (FTMP). Fault handling errors detected during fault injection experiments were characterized. In these fault injection experiments, the FTMP disabled a working unit instead of the faulted unit once in every 500 faults, on the average. System design weaknesses allow active faults to exercise a part of the fault management software that handles Byzantine or lying faults. Byzantine faults behave such that the faulted unit points to a working unit as the source of errors. The design's problems involve: (1) the design and interface between the simplex error detection hardware and the error processing software, (2) the functional capabilities of the FTMP system bus, and (3) the communication requirements of a multiprocessor architecture. These weak areas in the FTMP's design increase the probability that, for any hardware fault, a good line replacement unit (LRU) is mistakenly disabled by the fault management software.

  20. Fault detection and diagnosis in asymmetric multilevel inverter using artificial neural network

    NASA Astrophysics Data System (ADS)

    Raj, Nithin; Jagadanand, G.; George, Saly

    2018-04-01

    The increased component requirement to realise multilevel inverter (MLI) fallout in a higher fault prospect due to power semiconductors. In this scenario, efficient fault detection and diagnosis (FDD) strategies to detect and locate the power semiconductor faults have to be incorporated in addition to the conventional protection systems. Even though a number of FDD methods have been introduced in the symmetrical cascaded H-bridge (CHB) MLIs, very few methods address the FDD in asymmetric CHB-MLIs. In this paper, the gate-open circuit FDD strategy in asymmetric CHB-MLI is presented. Here, a single artificial neural network (ANN) is used to detect and diagnose the fault in both binary and trinary configurations of the asymmetric CHB-MLIs. In this method, features of the output voltage of the MLIs are used as to train the ANN for FDD method. The results prove the validity of the proposed method in detecting and locating the fault in both asymmetric MLI configurations. Finally, the ANN response to the input parameter variation is also analysed to access the performance of the proposed ANN-based FDD strategy.

  1. Generalized analytic solutions and response characteristics of magnetotelluric fields on anisotropic infinite faults

    NASA Astrophysics Data System (ADS)

    Bing, Xue; Yicai, Ji

    2018-06-01

    In order to understand directly and analyze accurately the detected magnetotelluric (MT) data on anisotropic infinite faults, two-dimensional partial differential equations of MT fields are used to establish a model of anisotropic infinite faults using the Fourier transform method. A multi-fault model is developed to expand the one-fault model. The transverse electric mode and transverse magnetic mode analytic solutions are derived using two-infinite-fault models. The infinite integral terms of the quasi-analytic solutions are discussed. The dual-fault model is computed using the finite element method to verify the correctness of the solutions. The MT responses of isotropic and anisotropic media are calculated to analyze the response functions by different anisotropic conductivity structures. The thickness and conductivity of the media, influencing MT responses, are discussed. The analytic principles are also given. The analysis results are significant to how MT responses are perceived and to the data interpretation of the complex anisotropic infinite faults.

  2. Imaging the crustal structure of Haiti's transpressional fault system using seismicity and tomography

    NASA Astrophysics Data System (ADS)

    Possee, D.; Keir, D.; Harmon, N.; Rychert, C.; Rolandone, F.; Leroy, S. D.; Stuart, G. W.; Calais, E.; Boisson, D.; Ulysse, S. M. J.; Guerrier, K.; Momplaisir, R.; Prepetit, C.

    2017-12-01

    Oblique convergence of the Caribbean and North American plates has partitioned strain across an extensive transpressional fault system that bisects Haiti. Most recently the 2010, MW7.0 earthquake ruptured multiple thrust faults in southern Haiti. However, while the rupture mechanism has been well studied, how these faults are segmented and link to deformation across the plate boundary is still debated. Understanding the link between strain accumulation and faulting in Haiti is also key to future modelling of seismic hazards. To assess seismic activity and fault structures we used data from 31 broadband seismic stations deployed on Haiti for 16-months. Local earthquakes were recorded and hypocentre locations determined using a 1D velocity model. A high-quality subset of the data was then inverted using travel-time tomography for relocated hypocentres and 2D images of Vp and Vp/Vs crustal structure. Earthquake locations reveal two clusters of seismic activity, the first delineates faults associated with the 2010 earthquake and the second shows activity 100km further east along a thrust fault north of Lake Enriquillo (Dominican Republic). The velocity models show large variations in seismic properties across the plate boundary; shallow low-velocity zones with a 5-8% decrease in Vp and high Vp/Vs ratios of 1.85-1.95 correspond to sedimentary basins that form the low-lying terrain on Haiti. We also image a region with a 4-5% decrease in Vp and an increased Vp/Vs ratio of 1.80-1.85 dipping south to a depth of 20km beneath southern Haiti. This feature matches the location of a major thrust fault and suggests a substantial damage zone around this fault. Beneath northern Haiti a transition to lower Vp/Vs values of 1.70-1.75 reflects a compositional change from mafic facies such as the Caribbean large igneous province in the south, to arc magmatic facies associated with the Greater Antilles arc in the north. Our seismic images are consistent with the fault system across

  3. Simulation of Co-Seismic Off-Fault Stress Effects: Influence of Fault Roughness and Pore Pressure Coupling

    NASA Astrophysics Data System (ADS)

    Fälth, B.; Lund, B.; Hökmark, H.

    2017-12-01

    Aiming at improved safety assessment of geological nuclear waste repositories, we use dynamic 3D earthquake simulations to estimate the potential for co-seismic off-fault distributed fracture slip. Our model comprises a 12.5 x 8.5 km strike-slip fault embedded in a full space continuum where we apply a homogeneous initial stress field. In the reference case (Case 1) the fault is planar and oriented optimally for slip, given the assumed stress field. To examine the potential impact of fault roughness, we also study cases where the fault surface has undulations with self-similar fractal properties. In both the planar and the undulated cases the fault has homogeneous frictional properties. In a set of ten rough fault models (Case 2), the fault friction is equal to that of Case 1, meaning that these models generate lower seismic moments than Case 1. In another set of ten rough fault models (Case 3), the fault dynamic friction is adjusted such that seismic moments on par with that of Case 1 are generated. For the propagation of the earthquake rupture we adopt the linear slip-weakening law and obtain Mw 6.4 in Case 1 and Case 3, and Mw 6.3 in Case 2 (35 % lower moment than Case 1). During rupture we monitor the off-fault stress evolution along the fault plane at 250 m distance and calculate the corresponding evolution of the Coulomb Failure Stress (CFS) on optimally oriented hypothetical fracture planes. For the stress-pore pressure coupling, we assume Skempton's coefficient B = 0.5 as a base case value, but also examine the sensitivity to variations of B. We observe the following: (I) The CFS values, and thus the potential for fracture slip, tend to increase with the distance from the hypocenter. This is in accordance with results by other authors. (II) The highest CFS values are generated by quasi-static stress concentrations around fault edges and around large scale fault bends, where we obtain values of the order of 10 MPa. (III) Locally, fault roughness may have a

  4. The 2011 Hawthorne, Nevada, Earthquake Sequence; Shallow Normal Faulting

    NASA Astrophysics Data System (ADS)

    Smith, K. D.; Johnson, C.; Davies, J. A.; Agbaje, T.; Knezevic Antonijevic, S.; Kent, G.

    2011-12-01

    An energetic sequence of shallow earthquakes that began in early March 2011 in western Nevada, near the community of Hawthorne, has slowly decreased in intensity through mid-2011. To date about 1300 reviewed earthquake locations have been compiled; we have computed moment tensors for the larger earthquakes and have developed a set of high-precision locations for all reviewed events. The sequence to date has included over 50 earthquakes ML 3 and larger with the largest at Mw 4.6. Three 6-channel portable stations configured with broadband sensors and accelerometers were installed by April 20. Data from the portable instruments is telemetered through NSL's microwave backbone to Reno where it is integrated with regional network data for real-time notifications, ShakeMaps, and routine event analysis. The data is provided in real-time to NEIC, CISN and the IRIS DMC. The sequence is located in a remote area about 15-20 km southwest of Hawthorne in the footwall block of the Wassuk Range fault system. An initial concern was that the sequence might be associated with volcanic processes due to the proximity of late Quaternary volcanic flows; there have been no volcanic signatures observed in near source seismograms. An additional concern, as the sequence has proceeded, was a clear progression eastward toward the Wassuk Range front fault. The east dipping range bounding fault is capable of M 7+ events, and poses a significant hazard to the community of Hawthorne and local military facilities. The Hawthorne Army Depot is an ordinance storage facility and the nation's storage site for surplus mercury. The sequence is within what has been termed the 'Mina Deflection' of the Central Walker Lane Belt. Faulting along the Whiskey Flat section of the Wassuk front fault would be primarily down-to-the-east, with an E-W extension direction; moment tensors for the 2011 earthquake show a range of extension directions from E-W to NW-SE, suggesting a possible dextral component to the Wassuk

  5. Distributed Fault Detection Based on Credibility and Cooperation for WSNs in Smart Grids.

    PubMed

    Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong

    2017-04-28

    Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based on credibility and cooperation. Firstly, a reasonable credibility model of a sensor is established to identify any suspicious status of the sensor according to its own temporal data correlation. Based on the credibility model, the suspicious sensor is then chosen to launch fault diagnosis requests. Secondly, the sending time of fault diagnosis request is discussed to avoid the transmission overhead brought about by unnecessary diagnosis requests and improve the efficiency of fault detection based on neighbor cooperation. The diagnosis reply of a neighbor sensor is analyzed according to its own status. Finally, to further improve the accuracy of fault detection, the diagnosis results of neighbors are divided into several classifications to judge the fault status of the sensors which launch the fault diagnosis requests. Simulation results show that this novel mechanism can achieve high fault detection ratio with a small number of fault diagnoses and low data congestion probability.

  6. Distributed Fault Detection Based on Credibility and Cooperation for WSNs in Smart Grids

    PubMed Central

    Shao, Sujie; Guo, Shaoyong; Qiu, Xuesong

    2017-01-01

    Due to the increasingly important role in monitoring and data collection that sensors play, accurate and timely fault detection is a key issue for wireless sensor networks (WSNs) in smart grids. This paper presents a novel distributed fault detection mechanism for WSNs based on credibility and cooperation. Firstly, a reasonable credibility model of a sensor is established to identify any suspicious status of the sensor according to its own temporal data correlation. Based on the credibility model, the suspicious sensor is then chosen to launch fault diagnosis requests. Secondly, the sending time of fault diagnosis request is discussed to avoid the transmission overhead brought about by unnecessary diagnosis requests and improve the efficiency of fault detection based on neighbor cooperation. The diagnosis reply of a neighbor sensor is analyzed according to its own status. Finally, to further improve the accuracy of fault detection, the diagnosis results of neighbors are divided into several classifications to judge the fault status of the sensors which launch the fault diagnosis requests. Simulation results show that this novel mechanism can achieve high fault detection ratio with a small number of fault diagnoses and low data congestion probability. PMID:28452925

  7. Earthquake mechanism and predictability shown by a laboratory fault

    USGS Publications Warehouse

    King, C.-Y.

    1994-01-01

    Slip events generated in a laboratory fault model consisting of a circulinear chain of eight spring-connected blocks of approximately equal weight elastically driven to slide on a frictional surface are studied. It is found that most of the input strain energy is released by a relatively few large events, which are approximately time predictable. A large event tends to roughen stress distribution along the fault, whereas the subsequent smaller events tend to smooth the stress distribution and prepare a condition of simultaneous criticality for the occurrence of the next large event. The frequency-size distribution resembles the Gutenberg-Richter relation for earthquakes, except for a falloff for the largest events due to the finite energy-storage capacity of the fault system. Slip distributions, in different events are commonly dissimilar. Stress drop, slip velocity, and rupture velocity all tend to increase with event size. Rupture-initiation locations are usually not close to the maximum-slip locations. ?? 1994 Birkha??user Verlag.

  8. Interseismic Strain Accumulation of the Gazikoy-Saros segment (Ganos fault) of the North Anatolian Fault Zone

    NASA Astrophysics Data System (ADS)

    Havazli, E.; Wdowinski, S.; Amelung, F.

    2017-12-01

    The North Anatolian Fault Zone (NAFZ) is one of the most active continental transform faults in the world. A westward migrating earthquake sequence has started in 1939 in Erzincan and the last two events of this sequence occurred in 1999 in Izmit and Duzce manifesting the importance of NAFZ on the seismic hazard potential of the region. NAFZ exhibits slip rates ranging from 14-30 mm/yr along its 1500 km length with a right lateral strike slip characteristic. In the East of the Marmara Sea, the NAFZ splits into two branches. The Gazikoy-Saros segment (Ganos Fault) is the westernmost and onshore segment of the northern branch. The ENE-WSW oriented Ganos Fault is seismically active. It produced a Ms 7.2 earthquake in 1912, which was followed by several large aftershocks, including Ms 6.3 and Ms 6.9 events. Since 1912, the Ganos Fault did not produce any significant earthquakes (> M 5), in contrast to its adjacent segments, which produced 20 M>5 earthquakes, including a M 6.7 event, offshore in Gulf of Saros. Interseismic strain accumulation along the Ganos Fault was assessed from sparse GPS measurements along a single transect located perpendicular to the fault zone, suggesting strain accumulation rate of 20-25 mm/yr. Insofar, InSAR studies, based on C-band data, didn't produce conclusive results due to low coherence over the fault zone area, which is highly vegetated. In this study, we present a detailed interseismic velocity map of the Ganos Fault zone derived from L-band InSAR observations. We use 21 ALOS PALSAR scenes acquired over a 5-year period, from 2007 to 2011. We processed the ALOS data using the PySAR software, which is the University of Miami version of the Small Baseline (SB) method. The L-band observations enabled us to overcome the coherence issue in the study area. Our initial results indicate a maximum velocity of 15 mm/yr across the fault zone. The high spatial resolution of the InSAR-based interseismic velocity map will enable us to better to

  9. Map showing recently active breaks along the San Andreas Fault between Pt. Delgada and Bolinas Bay, California

    USGS Publications Warehouse

    Brown, Robert D.; Wolfe, Edward W.

    1970-01-01

    This strip map is one of a series of maps showing recently active fault breaks along the San Andreas and other active faults in California. It is designed to inform persons who are concerned with land use near the fault of the location of those fault breaks that have moved recently. The lines on the map are lines of rupture and creep that can be identified by field evidence and that clearly affect the present surface of the land. Map users should keep in mind that these lines are intended primarily as guides to help locate the fault; the mapped lines are not necessarily shown with the precision demanded by some engineering or land utilization needs.

  10. Rolling bearing fault diagnosis and health assessment using EEMD and the adjustment Mahalanobis-Taguchi system

    NASA Astrophysics Data System (ADS)

    Chen, Junxun; Cheng, Longsheng; Yu, Hui; Hu, Shaolin

    2018-01-01

    ABSTRACTSFor the timely identification of the potential <span class="hlt">faults</span> of a rolling bearing and to observe its health condition intuitively and <span class="hlt">accurately</span>, a novel <span class="hlt">fault</span> diagnosis and health assessment model for a rolling bearing based on the ensemble empirical mode decomposition (EEMD) method and the adjustment Mahalanobis-Taguchi system (AMTS) method is proposed. The specific steps are as follows: First, the vibration signal of a rolling bearing is decomposed by EEMD, and the extracted features are used as the input vectors of AMTS. Then, the AMTS method, which is designed to overcome the shortcomings of the traditional Mahalanobis-Taguchi system and to extract the key features, is proposed for <span class="hlt">fault</span> diagnosis. Finally, a type of HI concept is proposed according to the results of the <span class="hlt">fault</span> diagnosis to accomplish the health assessment of a bearing in its life cycle. To validate the superiority of the developed method proposed approach, it is compared with other recent method and proposed methodology is successfully validated on a vibration data-set acquired from seeded defects and from an accelerated life test. The results show that this method represents the actual situation well and is able to <span class="hlt">accurately</span> and effectively identify the <span class="hlt">fault</span> type.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880011511','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880011511"><span>A <span class="hlt">fault</span> injection experiment using the AIRLAB Diagnostic Emulation Facility</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Baker, Robert; Mangum, Scott; Scheper, Charlotte</p> <p>1988-01-01</p> <p>The preparation for, conduct of, and results of a simulation based <span class="hlt">fault</span> injection experiment conducted using the AIRLAB Diagnostic Emulation facilities is described. An objective of this experiment was to determine the effectiveness of the diagnostic self-test sequences used to uncover latent <span class="hlt">faults</span> in a logic network providing the key <span class="hlt">fault</span> tolerance features for a flight control computer. Another objective was to develop methods, tools, and techniques for conducting the experiment. More than 1600 <span class="hlt">faults</span> were injected into a logic gate level model of the Data Communicator/Interstage (C/I). For each <span class="hlt">fault</span> injected, diagnostic self-test sequences consisting of over 300 test vectors were supplied to the C/I model as inputs. For each test vector within a test sequence, the outputs from the C/I model were compared to the outputs of a <span class="hlt">fault</span> free C/I. If the outputs differed, the <span class="hlt">fault</span> was considered detectable for the given test vector. These results were then analyzed to determine the effectiveness of some test sequences. The results established coverage of selt-test diagnostics, identified areas in the C/I logic where the tests did not <span class="hlt">locate</span> <span class="hlt">faults</span>, and suggest <span class="hlt">fault</span> latency reduction opportunities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28961219','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28961219"><span>A Novel Online Data-Driven Algorithm for Detecting UAV Navigation Sensor <span class="hlt">Faults</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Rui; Cheng, Qi; Wang, Guanyu; Ochieng, Washington Yotto</p> <p>2017-09-29</p> <p>The use of Unmanned Aerial Vehicles (UAVs) has increased significantly in recent years. On-board integrated navigation sensors are a key component of UAVs' flight control systems and are essential for flight safety. In order to ensure flight safety, timely and effective navigation sensor <span class="hlt">fault</span> detection capability is required. In this paper, a novel data-driven Adaptive Neuron Fuzzy Inference System (ANFIS)-based approach is presented for the detection of on-board navigation sensor <span class="hlt">faults</span> in UAVs. Contrary to the classic UAV sensor <span class="hlt">fault</span> detection algorithms, based on predefined or modelled <span class="hlt">faults</span>, the proposed algorithm combines an online data training mechanism with the ANFIS-based decision system. The main advantages of this algorithm are that it allows real-time model-free residual analysis from Kalman Filter (KF) estimates and the ANFIS to build a reliable <span class="hlt">fault</span> detection system. In addition, it allows fast and <span class="hlt">accurate</span> detection of <span class="hlt">faults</span>, which makes it suitable for real-time applications. Experimental results have demonstrated the effectiveness of the proposed <span class="hlt">fault</span> detection method in terms of accuracy and misdetection rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70020700','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70020700"><span>Evidence of shallow <span class="hlt">fault</span> zone strengthening after the 1992 M7.5 Landers, California, earthquake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Li, Y.-G.; Vidale, J.E.; Aki, K.; Xu, Fei; Burdette, T.</p> <p>1998-01-01</p> <p>Repeated seismic surveys of the Landers, California, <span class="hlt">fault</span> zone that ruptured in the magnitude (M) 7.5 earthquake of 1992 reveal an increase in seismic velocity with time. P, S, and <span class="hlt">fault</span> zone trapped waves were excited by near-surface explosions in two <span class="hlt">locations</span> in 1994 and 1996, and were recorded on two linear, three-component seismic arrays deployed across the Johnson Valley <span class="hlt">fault</span> trace. The travel times of P and S waves for identical shot-receiver pairs decreased by 0.5 to 1.5 percent from 1994 to 1996, with the larger changes at stations <span class="hlt">located</span> within the <span class="hlt">fault</span> zone. These observations indicate that the shallow Johnson Valley <span class="hlt">fault</span> is strengthening after the main shock, most likely because of closure of cracks that were opened by the 1992 earthquake. The increase in velocity is consistent with the prevalence of dry over wet cracks and with a reduction in the apparent crack density near the <span class="hlt">fault</span> zone by approximately 1.0 percent from 1994 to 1996.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.H53G1783D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.H53G1783D"><span>Evolution of groundwater chemistry along <span class="hlt">fault</span> structures in sandstone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dausse, A.; Guiheneuf, N.; Pierce, A. A.; Cherry, J. A.; Parker, B. L.</p> <p>2016-12-01</p> <p>Fluid-rock interaction across geological structures plays a major role on evolution of groundwater chemistry and physical properties of reservoirs. In particular, groundwater chemistry evolve on different facies according to residence times which can be linked to hydraulic properties of the geological unit. In this study, we analyze groundwater samples collected at an 11 km² site <span class="hlt">located</span> in southern California (USA) to evaluate the evolution of groundwater chemistry according to different geological structures. Major and minor elements were sampled at the same period of time from 40 wells <span class="hlt">located</span> along the main structures in the northeast of the site, where major NE-SW trending <span class="hlt">faults</span> and other oriented ESE-WNW are present in sandstone Chatsworth formation. By analyzing the spatial distribution of ions concentration at the site scale, several hydrochemical compartments (main- and sub-compartments) can be distinguished and are in agreement with structural and hydrological information. In particular, as previously observed from piezometric informations, the shear zone <span class="hlt">fault</span> serves as a barrier for groundwater flow and separates the site on two mains compartments. In addition, the analysis along major <span class="hlt">faults</span> oriented orthogonal to this shear zone (ESE-WNW) in the eastern part of the site, shows an increase in mineralization following the hydraulic gradient. This salinization has been confirmed by ionic ratio and Gibbs plots and is attributed to fluid-rock interaction processes. In particular, groundwater chemistry seems to evolve from bicarbonate to sodium facies. Moreover, the gradient of concentrations vary depending on <span class="hlt">fault</span> <span class="hlt">locations</span> and can be related to their hydraulic properties and hence to different characteristic times from point to point. To conclude, major <span class="hlt">faults</span> across the site display different degrees of groundwater chemistry evolution, linked to their physical properties, which may in turn have a large impact on contaminant transport and attenuation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JSG...108..230L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JSG...108..230L"><span>Spatial arrangement and size distribution of normal <span class="hlt">faults</span>, Buckskin detachment upper plate, Western Arizona</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laubach, S. E.; Hundley, T. H.; Hooker, J. N.; Marrett, R. A.</p> <p>2018-03-01</p> <p><span class="hlt">Fault</span> arrays typically include a wide range of <span class="hlt">fault</span> sizes and those <span class="hlt">faults</span> may be randomly <span class="hlt">located</span>, clustered together, or regularly or periodically <span class="hlt">located</span> in a rock volume. Here, we investigate size distribution and spatial arrangement of normal <span class="hlt">faults</span> using rigorous size-scaling methods and normalized correlation count (NCC). Outcrop data from Miocene sedimentary rocks in the immediate upper plate of the regional Buckskin detachment-low angle normal-<span class="hlt">fault</span>, have differing patterns of spatial arrangement as a function of displacement (offset). Using lower size-thresholds of 1, 0.1, 0.01, and 0.001 m, displacements range over 5 orders of magnitude and have power-law frequency distributions spanning ∼ four orders of magnitude from less than 0.001 m to more than 100 m, with exponents of -0.6 and -0.9. The largest <span class="hlt">faults</span> with >1 m displacement have a shallower size-distribution slope and regular spacing of about 20 m. In contrast, smaller <span class="hlt">faults</span> have steep size-distribution slopes and irregular spacing, with NCC plateau patterns indicating imposed clustering. Cluster widths are 15 m for the 0.1-m threshold, 14 m for 0.01-m, and 1 m for 0.001-m displacement threshold <span class="hlt">faults</span>. Results demonstrate normalized correlation count effectively characterizes the spatial arrangement patterns of these <span class="hlt">faults</span>. Our example from a high-strain <span class="hlt">fault</span> pattern above a detachment is compatible with size and spatial organization that was influenced primarily by boundary conditions such as <span class="hlt">fault</span> shape, mechanical unit thickness and internal stratigraphy on a range of scales rather than purely by interaction among <span class="hlt">faults</span> during their propagation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T31E..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T31E..08S"><span>The Bear River <span class="hlt">Fault</span> Zone, Wyoming and Utah: Complex Ruptures on a Young Normal <span class="hlt">Fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwartz, D. P.; Hecker, S.; Haproff, P.; Beukelman, G.; Erickson, B.</p> <p>2012-12-01</p> <p>The Bear River <span class="hlt">fault</span> zone (BRFZ), a set of normal <span class="hlt">fault</span> scarps <span class="hlt">located</span> in the Rocky Mountains at the eastern margin of Basin and Range extension, is a rare example of a nascent surface-rupturing <span class="hlt">fault</span>. Paleoseismic investigations (West, 1994; this study) indicate that the entire neotectonic history of the BRFZ may consist of two large surface-<span class="hlt">faulting</span> events in the late Holocene. We have estimated a maximum per-event vertical displacement of 6-6.5 m at the south end of the <span class="hlt">fault</span> where it abuts the north flank of the east-west-trending Uinta Mountains. However, large hanging-wall depressions resulting from back rotation, which front scarps that locally exceed 15 m in height, are prevalent along the main trace, obscuring the net displacement and its along-strike distribution. The modest length (~35 km) of the BRFZ indicates ruptures with a large displacement-to-length ratio, which implies earthquakes with a high static stress drop. The BRFZ is one of several immature (low cumulative displacement) normal <span class="hlt">faults</span> in the Rocky Mountain region that appear to produce high-stress drop earthquakes. West (1992) interpreted the BRFZ as an extensionally reactivated ramp of the late Cretaceous-early Tertiary Hogsback thrust. LiDAR data on the southern section of the <span class="hlt">fault</span> and Google Earth imagery show that these young ruptures are more extensive than currently mapped, with newly identified large (>10m) antithetic scarps and footwall graben. The scarps of the BRFZ extend across a 2.5-5.0 km-wide zone, making this the widest and most complex Holocene surface rupture in the Intermountain West. The broad distribution of Late Holocene scarps is consistent with reactivation of shallow bedrock structures but the overall geometry of the BRFZ at depth and its extent into the seismogenic zone are uncertain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030111237&hterms=fracturing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfracturing','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030111237&hterms=fracturing&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dfracturing"><span>Secondary Fracturing of Europa's Crust in Response to Combined Slip and Dilation Along Strike-Slip <span class="hlt">Faults</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kattenhorn, S. A.</p> <p>2003-01-01</p> <p>A commonly observed feature in <span class="hlt">faulted</span> terrestrial rocks is the occurrence of secondary fractures alongside <span class="hlt">faults</span>. Depending on exact morphology, such fractures have been termed tail cracks, wing cracks, kinks, or horsetail fractures, and typically form at the tip of a slipping <span class="hlt">fault</span> or around small jogs or steps along a <span class="hlt">fault</span> surface. The <span class="hlt">location</span> and orientation of secondary fracturing with respect to the <span class="hlt">fault</span> plane or the <span class="hlt">fault</span> tip can be used to determine if <span class="hlt">fault</span> motion is left-lateral or right-lateral.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T22D..06G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T22D..06G"><span>Distributing Earthquakes Among California's <span class="hlt">Faults</span>: A Binary Integer Programming Approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geist, E. L.; Parsons, T.</p> <p>2016-12-01</p> <p>Statement of the problem is simple: given regional seismicity specified by a Gutenber-Richter (G-R) relation, how are earthquakes distributed to match observed <span class="hlt">fault</span>-slip rates? The objective is to determine the magnitude-frequency relation on individual <span class="hlt">faults</span>. The California statewide G-R b-value and a-value are estimated from historical seismicity, with the a-value accounting for off-<span class="hlt">fault</span> seismicity. UCERF3 consensus slip rates are used, based on geologic and geodetic data and include estimates of coupling coefficients. The binary integer programming (BIP) problem is set up such that each earthquake from a synthetic catalog spanning millennia can occur at any <span class="hlt">location</span> along any <span class="hlt">fault</span>. The decision vector, therefore, consists of binary variables, with values equal to one indicating the <span class="hlt">location</span> of each earthquake that results in an optimal match of slip rates, in an L1-norm sense. Rupture area and slip associated with each earthquake are determined from a magnitude-area scaling relation. Uncertainty bounds on the UCERF3 slip rates provide explicit minimum and maximum constraints to the BIP model, with the former more important to feasibility of the problem. There is a maximum magnitude limit associated with each <span class="hlt">fault</span>, based on <span class="hlt">fault</span> length, providing an implicit constraint. Solution of integer programming problems with a large number of variables (>105 in this study) has been possible only since the late 1990s. In addition to the classic branch-and-bound technique used for these problems, several other algorithms have been recently developed, including pre-solving, sifting, cutting planes, heuristics, and parallelization. An optimal solution is obtained using a state-of-the-art BIP solver for M≥6 earthquakes and California's <span class="hlt">faults</span> with slip-rates > 1 mm/yr. Preliminary results indicate a surprising diversity of on-<span class="hlt">fault</span> magnitude-frequency relations throughout the state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20728631','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20728631"><span>Analyzing <span class="hlt">fault</span> in pedestrian-motor vehicle crashes in North Carolina.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ulfarsson, Gudmundur F; Kim, Sungyop; Booth, Kathleen M</p> <p>2010-11-01</p> <p>Crashes between pedestrians and motor vehicles are an important traffic safety concern. This paper explores the assignment of <span class="hlt">fault</span> in such crashes, where observed factors are associated with pedestrian at <span class="hlt">fault</span>, driver at <span class="hlt">fault</span>, or both at <span class="hlt">fault</span>. The analysis is based on police reported crash data for 1997 through 2000 in North Carolina, U.S.A. The results show that pedestrians are found at <span class="hlt">fault</span> in 59% of the crashes, drivers in 32%, and both are found at <span class="hlt">fault</span> in 9%. The results indicate drivers need to take greater notice of pedestrians when drivers are turning, merging, and backing up as these are some of the prime factors associated with the driver being found at <span class="hlt">fault</span> in a crash. Pedestrians must apply greater caution when crossing streets, waiting to cross, and when walking along roads, as these are correlated with pedestrians being found at <span class="hlt">fault</span>. The results suggest a need for campaigns focused on positively affecting pedestrian street-crossing behavior in combination with added jaywalking enforcement. The results also indicate that campaigns to increase the use of pedestrian visibility improvements at night can have a significant positive impact on traffic safety. Intoxication is a concern and the results show that it is not only driver intoxication that is affecting safety, but also pedestrian intoxication. The findings show in combination with other research in the field, that results from traffic safety studies are not necessarily transferable between distant geographic <span class="hlt">locations</span>, and that <span class="hlt">location</span>-specific safety research needs to take place. It is also important to further study the specific effects of the design of the pedestrian environment on safety, e.g. crosswalk spacing, signal timings, etc., which together may affect pedestrian safety and pedestrian behavior. 2010 Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70046870','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70046870"><span>Geometry and earthquake potential of the shoreline <span class="hlt">fault</span>, central California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hardebeck, Jeanne L.</p> <p>2013-01-01</p> <p>The Shoreline <span class="hlt">fault</span> is a vertical strike‐slip <span class="hlt">fault</span> running along the coastline near San Luis Obispo, California. Much is unknown about the Shoreline <span class="hlt">fault</span>, including its slip rate and the details of its geometry. Here, I study the geometry of the Shoreline <span class="hlt">fault</span> at seismogenic depth, as well as the adjacent section of the offshore Hosgri <span class="hlt">fault</span>, using seismicity relocations and earthquake focal mechanisms. The Optimal Anisotropic Dynamic Clustering (OADC) algorithm (Ouillon et al., 2008) is used to objectively identify the simplest planar <span class="hlt">fault</span> geometry that fits all of the earthquakes to within their <span class="hlt">location</span> uncertainty. The OADC results show that the Shoreline <span class="hlt">fault</span> is a single continuous structure that connects to the Hosgri <span class="hlt">fault</span>. Discontinuities smaller than about 1 km may be undetected, but would be too small to be barriers to earthquake rupture. The Hosgri <span class="hlt">fault</span> dips steeply to the east, while the Shoreline <span class="hlt">fault</span> is essentially vertical, so the Hosgri <span class="hlt">fault</span> dips towards and under the Shoreline <span class="hlt">fault</span> as the two <span class="hlt">faults</span> approach their intersection. The focal mechanisms generally agree with pure right‐lateral strike‐slip on the OADC planes, but suggest a non‐planar Hosgri <span class="hlt">fault</span> or another structure underlying the northern Shoreline <span class="hlt">fault</span>. The Shoreline <span class="hlt">fault</span> most likely transfers strike‐slip motion between the Hosgri <span class="hlt">fault</span> and other <span class="hlt">faults</span> of the Pacific–North America plate boundary system to the east. A hypothetical earthquake rupturing the entire known length of the Shoreline <span class="hlt">fault</span> would have a moment magnitude of 6.4–6.8. A hypothetical earthquake rupturing the Shoreline <span class="hlt">fault</span> and the section of the Hosgri <span class="hlt">fault</span> north of the Hosgri–Shoreline junction would have a moment magnitude of 7.2–7.5.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1422763','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/1422763"><span>Detection of arcing <span class="hlt">location</span> on photovoltaic systems using filters</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Johnson, Jay</p> <p>2018-02-20</p> <p>The present invention relates to photovoltaic systems capable of identifying the <span class="hlt">location</span> of an arc-<span class="hlt">fault</span>. In particular, such systems include a unique filter connected to each photovoltaic (PV) string, thereby providing a unique filtered noise profile associated with a particular PV string. Also described herein are methods for identifying and isolating such arc-<span class="hlt">faults</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996LPI....27..373F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996LPI....27..373F"><span>Analysis of <span class="hlt">Fault</span> Lengths Across Valles Marineris, Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fori, A. N.; Schultz, R. A.</p> <p>1996-03-01</p> <p>Summary. As part of a larger project to determine the history of stress and strain across Valles Marineris, Mars, graben lengths <span class="hlt">located</span> within the Valley are measured using a two-dimensional window-sampling method to investigate depth of <span class="hlt">faulting</span> and accuracy of measurement. The resulting degree of uncertainty in measuring lengths (+19 km - 80% accuracy) is independent of the resolution at which the <span class="hlt">faults</span> are measured, so data sets and resultant statistical analysis from different scales or map areas can be compared. The cumulative length frequency plots show that the geometry of Valley <span class="hlt">faults</span> display no evidence of a frictional stability transition at depth in the lithosphere if mechanical interaction between individual <span class="hlt">faults</span> (an unphysical situation) is not considered. If strongly interacting <span class="hlt">faults</span> are linked and the composite lengths used to re-create the cumulative lengths plots, a significant change in slope is apparent suggesting the existence of a transition at about 35-65 km below the surface (assuming <span class="hlt">faults</span> are dipping from 50deg to 70deg This suggests the thermal gradient to the associated 300-400degC isotherm is 53C/km to 12degC/km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70035963','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70035963"><span>Slip maxima at <span class="hlt">fault</span> junctions and rupturing of barriers during the 2008 Wenchuan earthquake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shen, Z.-K.; Sun, Jielun; Zhang, P.; Wan, Y.; Wang, M.; Burgmann, R.; Zeng, Y.; Gan, Weijun; Liao, H.; Wang, Q.</p> <p>2009-01-01</p> <p>The disastrous 12 May 2008 Wenchuan earthquake in China took the local population as well as scientists by surprise. Although the Longmen Shan <span class="hlt">fault</span> zonewhich includes the <span class="hlt">fault</span> segments along which this earthquake nucleatedwas well known, geologic and geodetic data indicate relatively low (<3 mm yr -1) deformation rates. Here we invert Global Positioning System and Interferometric Synthetic Aperture Radar data to infer <span class="hlt">fault</span> geometry and slip distribution associated with the earthquake. Our analysis shows that the geometry of the <span class="hlt">fault</span> changes along its length: in the southwest, the <span class="hlt">fault</span> plane dips moderately to the northwest but becomes nearly vertical in the northeast. Associated with this is a change in the motion along the <span class="hlt">fault</span> from predominantly thrusting to strike-slip. Peak slip along the <span class="hlt">fault</span> occurs at the intersections of <span class="hlt">fault</span> segments <span class="hlt">located</span> near the towns of Yingxiu, Beichuan and Nanba, where fatalities and damage were concentrated. We suggest that these <span class="hlt">locations</span> represent barriers that failed in a single event, enabling the rupture to cascade through several <span class="hlt">fault</span> segments and cause a major moment magnitude (Mw) 7.9 earthquake. Using coseismic slip distribution and geodetic and geological slip rates, we estimate that the failure of barriers and rupture along multiple segments takes place approximately once in 4,000 years. ?? 2009 Macmillan Publishers Limited. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70037704','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70037704"><span>Shallow subsurface structure of the Wasatch <span class="hlt">fault</span>, Provo segment, Utah, from integrated compressional and shear-wave seismic reflection profiles with implications for <span class="hlt">fault</span> structure and development</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McBride, J.H.; Stephenson, W.J.; Williams, R.A.; Odum, J.K.; Worley, D.M.; South, J.V.; Brinkerhoff, A.R.; Keach, R.W.; Okojie-Ayoro, A. O.</p> <p>2010-01-01</p> <p>Integrated vibroseis compressional and experimental hammer-source, shear-wave, seismic reflection profiles across the Provo segment of the Wasatch <span class="hlt">fault</span> zone in Utah reveal near-surface and shallow bedrock structures caused by geologically recent deformation. Combining information from the seismic surveys, geologic mapping, terrain analysis, and previous seismic first-arrival modeling provides a well-constrained cross section of the upper ~500 m of the subsurface. <span class="hlt">Faults</span> are mapped from the surface, through shallow, poorly consolidated deltaic sediments, and cutting through a rigid bedrock surface. The new seismic data are used to test hypotheses on changing <span class="hlt">fault</span> orientation with depth, the number of subsidiary <span class="hlt">faults</span> within the <span class="hlt">fault</span> zone and the width of the <span class="hlt">fault</span> zone, and the utility of integrating separate elastic methods to provide information on a complex structural zone. Although previous surface mapping has indicated only a few <span class="hlt">faults</span>, the seismic section shows a wider and more complex deformation zone with both synthetic and antithetic normal <span class="hlt">faults</span>. Our study demonstrates the usefulness of a combined shallow and deeper penetrating geophysical survey, integrated with detailed geologic mapping to constrain subsurface <span class="hlt">fault</span> structure. Due to the complexity of the <span class="hlt">fault</span> zone, <span class="hlt">accurate</span> seismic velocity information is essential and was obtained from a first-break tomography model. The new constraints on <span class="hlt">fault</span> geometry can be used to refine estimates of vertical versus lateral tectonic movements and to improve seismic hazard assessment along the Wasatch <span class="hlt">fault</span> through an urban area. We suggest that earthquake-hazard assessments made without seismic reflection imaging may be biased by the previous mapping of too few <span class="hlt">faults</span>. ?? 2010 Geological Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T22B..03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T22B..03K"><span>Earthquake behavior along the Levant <span class="hlt">fault</span> from paleoseismology (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Klinger, Y.; Le Beon, M.; Wechsler, N.; Rockwell, T. K.</p> <p>2013-12-01</p> <p>The Levant <span class="hlt">fault</span> is a major continental structure 1200 km-long that bounds the Arabian plate to the west. The finite offset of this left-lateral strike-slip <span class="hlt">fault</span> is estimated to be 105 km for the section <span class="hlt">located</span> south of the restraining bend corresponding roughly to Lebanon. Along this southern section the slip-rate has been estimated over a large range of time scales, from few years to few hundreds thousands of years. Over these different time scales, studies agree for the slip-rate to be 5mm/yr × 2 mm/yr. The southern section of the Levant <span class="hlt">fault</span> is particularly attractive to study earthquake behavior through time for several reasons: 1/ The <span class="hlt">fault</span> geometry is simple and well constrained. 2/ The <span class="hlt">fault</span> system is isolated and does not interact with obvious neighbor <span class="hlt">fault</span> systems. 3/ The Middle-East, where the Levant <span class="hlt">fault</span> is <span class="hlt">located</span>, is the region in the world where one finds the longest and most complete historical record of past earthquakes. About 30 km north of the city of Aqaba, we opened a trench in the southern part of the Yotvata playa, along the Wadi Araba <span class="hlt">fault</span> segment. The stratigraphy presents silty sand playa units alternating with coarser sand sediments from alluvial fans flowing westwards from the Jordan plateau. Two <span class="hlt">fault</span> zones can be recognized in the trench and a minimum of 8 earthquakes can be identified, based on upward terminations of ground ruptures. Dense 14C dating through the entire exposure allows matching the 4 most recent events with historical events in AD1458, AD1212, AD1068 and AD748. Size of the ground rupture suggests a bi-modal distribution of earthquakes with earthquakes rupturing the entire Wadi Araba segment and earthquakes ending in the extensional jog forming the playa. Timing of earthquakes shows that no earthquakes occurred at this site since about 600 years, suggesting earthquake clustering along this section of the <span class="hlt">fault</span> and potential for a large earthquake in the near future. 3D paleoseismological trenches at the Beteiha</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.T51A1332O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.T51A1332O"><span>Subsurface Resistivity Structures in and Around Strike-Slip <span class="hlt">Faults</span> - Electromagnetic Surveys and Drillings Across Active <span class="hlt">Faults</span> in Central Japan -</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Omura, K.; Ikeda, R.; Iio, Y.; Matsuda, T.</p> <p>2005-12-01</p> <p>Electrical resistivity is important property to investigate the structure of active <span class="hlt">faults</span>. Pore fluid affect seriously the electrical properties of rocks, subsurface electrical resistivity can be an indicator of the existence of fluid and distribution of pores. Fracture zone of <span class="hlt">fault</span> is expected to have low resistivity due to high porosity and small gain size. Especially, strike-slip type <span class="hlt">fault</span> has nearly vertical fracture zone and the fracture zone would be detected by an electrical survey across the <span class="hlt">fault</span>. We performed electromagnetic survey across the strike-slip active <span class="hlt">faults</span> in central Japan. At the same <span class="hlt">faults</span>, we also drilled borehole into the <span class="hlt">fault</span> and did downhole logging in the borehole. We applied MT or CSAMT methods onto 5 <span class="hlt">faults</span>: Nojima <span class="hlt">fault</span> which appeared on the surface by the 1995 Great Kobe earthquake (M=7.2), western Nagano Ohtaki area(1984 Nagano-ken seibu earthquake (M=6.8), the <span class="hlt">fault</span> did not appeared on the surface), Neodani <span class="hlt">fault</span> which appeared by the 1891 Nobi earthquake (M=8.0), Atera <span class="hlt">fault</span> which seemed to be dislocated by the 1586 Tensyo earthquake (M=7.9), Gofukuji <span class="hlt">fault</span> that is considered to have activated about 1200 years ago. The sampling frequencies of electrical and magnetic field were 2 - 1024Hz (10 frequencies) for CSAMT survey and 0.00055 - 384Hz (40 frequencies) for MT survey. The electromagnetic data were processed by standard method and inverted to 2-D resistivity structure along transects of the <span class="hlt">faults</span>. Results of the survey were compared with downhole electrical logging data and observational descriptions of drilled cores. <span class="hlt">Fault</span> plane of each <span class="hlt">fault</span> were recognized as low resistivity region or boundary between relatively low and high resistivity region, except for Gofukuji <span class="hlt">fault</span>. As for Gofukuji <span class="hlt">fault</span>, <span class="hlt">fault</span> was <span class="hlt">located</span> in relatively high resistivity region. During very long elapsed time from the last earthquake, the properties of fracture zone of Gofukuji <span class="hlt">fault</span> might changed from low resistivity properties as observed for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1111657-fault-imaging-high-resolution-seismic-reflection-earthquake-hazard-geothermal-resource-assessment-reno-nevada','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1111657-fault-imaging-high-resolution-seismic-reflection-earthquake-hazard-geothermal-resource-assessment-reno-nevada"><span><span class="hlt">Fault</span> Imaging with High-Resolution Seismic Reflection for Earthquake Hazard and Geothermal Resource Assessment in Reno, Nevada</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Frary, Roxanna</p> <p>2012-05-05</p> <p>The Truckee Meadows basin is situated adjacent to the Sierra Nevada microplate, on the western boundary of the Walker Lane. Being in the transition zone between a range-front normal <span class="hlt">fault</span> on the west and northwest-striking right-lateral strike slip <span class="hlt">faults</span> to the east, there is no absence of <span class="hlt">faulting</span> in this basin. The Reno- Sparks metropolitan area is <span class="hlt">located</span> in this basin, and with a signi cant population living here, it is important to know where these <span class="hlt">faults</span> are. High-resolution seismic reflection surveys are used for the imaging of these <span class="hlt">faults</span> along the Truckee River, across which only one <span class="hlt">fault</span> wasmore » previously mapped, and in southern Reno near and along Manzanita Lane, where a swarm of short <span class="hlt">faults</span> has been mapped. The reflection profiles constrain the geometries of these <span class="hlt">faults</span>, and suggest additional <span class="hlt">faults</span> not seen before. Used in conjunction with depth to bedrock calculations and gravity measurements, the seismic reflection surveys provide de nitive <span class="hlt">locations</span> of <span class="hlt">faults</span>, as well as their orientations. O sets on these <span class="hlt">faults</span> indicate how active they are, and this in turn has implications for seismic hazard in the area. In addition to seismic hazard, the <span class="hlt">faults</span> imaged here tell us something about the conduits for geothermal fluid resources in Reno.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012IJTJE..29..111Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012IJTJE..29..111Y"><span>Evidential Networks for <span class="hlt">Fault</span> Tree Analysis with Imprecise Knowledge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Jianping; Huang, Hong-Zhong; Liu, Yu; Li, Yan-Feng</p> <p>2012-06-01</p> <p><span class="hlt">Fault</span> tree analysis (FTA), as one of the powerful tools in reliability engineering, has been widely used to enhance system quality attributes. In most <span class="hlt">fault</span> tree analyses, precise values are adopted to represent the probabilities of occurrence of those events. Due to the lack of sufficient data or imprecision of existing data at the early stage of product design, it is often difficult to <span class="hlt">accurately</span> estimate the failure rates of individual events or the probabilities of occurrence of the events. Therefore, such imprecision and uncertainty need to be taken into account in reliability analysis. In this paper, the evidential networks (EN) are employed to quantify and propagate the aforementioned uncertainty and imprecision in <span class="hlt">fault</span> tree analysis. The detailed conversion processes of some logic gates to EN are described in <span class="hlt">fault</span> tree (FT). The figures of the logic gates and the converted equivalent EN, together with the associated truth tables and the conditional belief mass tables, are also presented in this work. The new epistemic importance is proposed to describe the effect of ignorance degree of event. The <span class="hlt">fault</span> tree of an aircraft engine damaged by oil filter plugs is presented to demonstrate the proposed method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70187040','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70187040"><span>San Andreas tremor cascades define deep <span class="hlt">fault</span> zone complexity</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Shelly, David R.</p> <p>2015-01-01</p> <p>Weak seismic vibrations - tectonic tremor - can be used to delineate some plate boundary <span class="hlt">faults</span>. Tremor on the deep San Andreas <span class="hlt">Fault</span>, <span class="hlt">located</span> at the boundary between the Pacific and North American plates, is thought to be a passive indicator of slow <span class="hlt">fault</span> slip. San Andreas <span class="hlt">Fault</span> tremor migrates at up to 30 m s-1, but the processes regulating tremor migration are unclear. Here I use a 12-year catalogue of more than 850,000 low-frequency earthquakes to systematically analyse the high-speed migration of tremor along the San Andreas <span class="hlt">Fault</span>. I find that tremor migrates most effectively through regions of greatest tremor production and does not propagate through regions with gaps in tremor production. I interpret the rapid tremor migration as a self-regulating cascade of seismic ruptures along the <span class="hlt">fault</span>, which implies that tremor may be an active, rather than passive participant in the slip propagation. I also identify an isolated group of tremor sources that are offset eastwards beneath the San Andreas <span class="hlt">Fault</span>, possibly indicative of the interface between the Monterey Microplate, a hypothesized remnant of the subducted Farallon Plate, and the North American Plate. These observations illustrate a possible link between the central San Andreas <span class="hlt">Fault</span> and tremor-producing subduction zones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920063374&hterms=evaluation+framework&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Devaluation%2Bframework','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920063374&hterms=evaluation+framework&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Devaluation%2Bframework"><span>Probabilistic evaluation of on-line checks in <span class="hlt">fault</span>-tolerant multiprocessor systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nair, V. S. S.; Hoskote, Yatin V.; Abraham, Jacob A.</p> <p>1992-01-01</p> <p>The analysis of <span class="hlt">fault</span>-tolerant multiprocessor systems that use concurrent error detection (CED) schemes is much more difficult than the analysis of conventional <span class="hlt">fault</span>-tolerant architectures. Various analytical techniques have been proposed to evaluate CED schemes deterministically. However, these approaches are based on worst-case assumptions related to the failure of system components. Often, the evaluation results do not reflect the actual <span class="hlt">fault</span> tolerance capabilities of the system. A probabilistic approach to evaluate the <span class="hlt">fault</span> detecting and <span class="hlt">locating</span> capabilities of on-line checks in a system is developed. The various probabilities associated with the checking schemes are identified and used in the framework of the matrix-based model. Based on these probabilistic matrices, estimates for the <span class="hlt">fault</span> tolerance capabilities of various systems are derived analytically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S23F..04M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S23F..04M"><span>Microseismic Analysis of Fracture of an Intact Rock Asperity Traversing a Sawcut <span class="hlt">Fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mclaskey, G.; Lockner, D. A.</p> <p>2017-12-01</p> <p>Microseismic events carry information related to stress state, <span class="hlt">fault</span> geometry, and other subsurface properties, but their relationship to large and potentially damaging earthquakes is not well defined. We conducted laboratory rock mechanics experiments that highlight the interaction between a sawcut <span class="hlt">fault</span> and an asperity composed of an intact rock "pin". The sample is a 76 mm diameter cylinder of Westerly granite with a 21 mm diameter cylinder (the pin) of intact Westerly granite that crosses the sawcut <span class="hlt">fault</span>. Upon loading to 80 MPa in a triaxial machine, we first observed a slip event that ruptured the sawcut <span class="hlt">fault</span>, slipped about 35 mm, but was halted by the rock pin. With continued loading, the rock pin failed in a swarm of thousands of M -7 seismic events similar to the localized microcracking that occurs during the final fracture nucleation phase in an intact rock sample. Once the pin was fractured to a critical point, it permitted complete rupture events on the sawcut <span class="hlt">fault</span> (stick-slip instabilities). No seismicity was detected on the sawcut <span class="hlt">fault</span> plane until the pin was sheared. Subsequent slip events were preceded by 10s of foreshocks, all <span class="hlt">located</span> on the <span class="hlt">fault</span> plane. We also identified an aseismic zone on the <span class="hlt">fault</span> plane surrounding the fractured rock pin. A post-mortem analysis of the sample showed a thick gouge layer where the pin intersected the <span class="hlt">fault</span>, suggesting that this gouge propped open the <span class="hlt">fault</span> and prevented microseismic events in its vicinity. This experiment is an excellent case study in microseismicity since the events separate neatly into three categories: slip on the sawcut <span class="hlt">fault</span>, fracture of the intact rock pin, and off-<span class="hlt">fault</span> seismicity associated with pin-related rock joints. The distinct <span class="hlt">locations</span>, timing, and focal mechanisms of the different categories of microseismic events allow us to study how their occurrence is related to the mechanics of the deforming rock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1975/of75-41/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1975/of75-41/"><span>A review of recently active <span class="hlt">faults</span> in Taiwan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bonilla, Manuel G.</p> <p>1975-01-01</p> <p>Six <span class="hlt">faults</span> associated with five large earthquakes produced surface displacements ranging from 1 to 3 m in the period 1906 through 1951. Four of the ruptures occurred in the western coastal plain and foothills, and two occurred in the Longitudinal Valley of eastern Taiwan. Maps are included showing the <span class="hlt">locations</span> and dimensions of the displacements. The published geological literature probably would not lead one to infer the existence of a <span class="hlt">fault</span> along most of the 1906 rupture, except for descriptions of the rupture itself. Over most of its length the 1935 rupture on the Chihhu <span class="hlt">fault</span> is parallel to but more than 0.5 km from nearby <span class="hlt">faults</span> shown on geologic maps published in 1969 and 1971; only about 1.5 km of its 15 km length coincides with a mapped <span class="hlt">fault</span>. The coastal plain part of the Tuntzuchio <span class="hlt">fault</span> which ruptured in 1935 is apparently not revealed by landforms, and only suggested by other data. Part of the 1946 Hsinhua <span class="hlt">faulting</span> coincides with a <span class="hlt">fault</span> identified in the subsurface by seismic work but surface indications of the <span class="hlt">fault</span> are obscure. The 1951 Meilun <span class="hlt">faulting</span> occurred along a conspicuous pre-1951 scarp and the 1951 Yuli <span class="hlt">faulting</span> occurred near or in line with pre-1951 scarps. More than 40 <span class="hlt">faults</span> which, according to the published literature, have had Pleistocene or later movement are shown on a small-scale map. Most of these <span class="hlt">faults</span> are in the densely-populated western part of Taiwan. The map and text calls attention to <span class="hlt">faults</span> that may be active and therefore may be significant in planning important structures. Equivocal evidence suggestive of <span class="hlt">fault</span> creep was found on the Yuli <span class="hlt">fault</span> and the Hsinhua <span class="hlt">fault</span>. <span class="hlt">Fault</span> creep was not found at several places examined along the 1906 <span class="hlt">fault</span> trace. Tectonic uplift has occurred in Taiwan in the last 10,000 years and application of eustatic sea level curves to published radiocarbon dates shows that the minimum rate of uplift is considerably different in different parts of the island. Incomplete data indicate that the rate is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSeis..21.1397J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSeis..21.1397J"><span>On <span class="hlt">fault</span> evidence for a large earthquake in the late fifteenth century, Eastern Kunlun <span class="hlt">fault</span>, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Junlong, Zhang</p> <p>2017-11-01</p> <p>The EW-trending Kunlun <span class="hlt">Fault</span> System (KFS) is one of the major left-lateral strike-slip <span class="hlt">faults</span> on the Tibetan Plateau. It forms the northern boundary of the Bayan Har block. Heretofore, no evidence has been provided for the most recent event (MRE) of the 70-km-long eastern section of the KFS. The studied area is <span class="hlt">located</span> in the north of the Zoige Basin (northwest Sichuan province) and was recognized by field mapping. Several trenches were excavated and revealed evidence of repeated events in late Holocene. The <span class="hlt">fault</span> zone is characterized by a distinct 30-60-cm-thick clay <span class="hlt">fault</span> gouge layer juxtaposing the hanging wall bedrock over unconsolidated late Holocene footwall colluvium and alluvium. The <span class="hlt">fault</span> zone, hanging wall, and footwall were conformably overlain by undeformed post-MRE deposits. Samples of charred organic material were obtained from the top of the <span class="hlt">faulted</span> sediments and the base of the unfaulted sediments. Modeling of the age of samples, earthquake yielded a calibrated 2σ radiocarbon age of A.D. 1489 ± 82. Combined with the historical earthquake record, the MRE is dated at A.D. 1488. Based on the over 50 km-long surface rupture, the magnitude of this event is nearly M w 7.0. Our data suggests that a 200-km-long seismic gap could be further divided into the Luocha and Maqu sections. For the last 1000 years, the Maqu section has been inactive, and hence, it is likely that the end of its seismic cycle is approaching, and that there is a potentially significant seismic hazard in eastern Tibet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950059069&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2526%25231041','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950059069&hterms=1041&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2526%25231041"><span>FTAPE: A <span class="hlt">fault</span> injection tool to measure <span class="hlt">fault</span> tolerance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tsai, Timothy K.; Iyer, Ravishankar K.</p> <p>1995-01-01</p> <p>The paper introduces FTAPE (<span class="hlt">Fault</span> Tolerance And Performance Evaluator), a tool that can be used to compare <span class="hlt">fault</span>-tolerant computers. The tool combines system-wide <span class="hlt">fault</span> injection with a controllable workload. A workload generator is used to create high stress conditions for the machine. <span class="hlt">Faults</span> are injected based on this workload activity in order to ensure a high level of <span class="hlt">fault</span> propagation. The errors/<span class="hlt">fault</span> ratio and performance degradation are presented as measures of <span class="hlt">fault</span> tolerance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GeoJI.155..111F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GeoJI.155..111F"><span><span class="hlt">Fault</span> compaction and overpressured <span class="hlt">faults</span>: results from a 3-D model of a ductile <span class="hlt">fault</span> zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fitzenz, D. D.; Miller, S. A.</p> <p>2003-10-01</p> <p>A model of a ductile <span class="hlt">fault</span> zone is incorporated into a forward 3-D earthquake model to better constrain <span class="hlt">fault</span>-zone hydraulics. The conceptual framework of the model <span class="hlt">fault</span> zone was chosen such that two distinct parts are recognized. The <span class="hlt">fault</span> core, characterized by a relatively low permeability, is composed of a coseismic <span class="hlt">fault</span> surface embedded in a visco-elastic volume that can creep and compact. The <span class="hlt">fault</span> core is surrounded by, and mostly sealed from, a high permeability damaged zone. The model <span class="hlt">fault</span> properties correspond explicitly to those of the coseismic <span class="hlt">fault</span> core. Porosity and pore pressure evolve to account for the viscous compaction of the <span class="hlt">fault</span> core, while stresses evolve in response to the applied tectonic loading and to shear creep of the <span class="hlt">fault</span> itself. A small diffusive leakage is allowed in and out of the <span class="hlt">fault</span> zone. Coseismically, porosity is created to account for frictional dilatancy. We show in the case of a 3-D <span class="hlt">fault</span> model with no in-plane flow and constant fluid compressibility, pore pressures do not drop to hydrostatic levels after a seismic rupture, leading to an overpressured weak <span class="hlt">fault</span>. Since pore pressure plays a key role in the <span class="hlt">fault</span> behaviour, we investigate coseismic hydraulic property changes. In the full 3-D model, pore pressures vary instantaneously by the poroelastic effect during the propagation of the rupture. Once the stress state stabilizes, pore pressures are incrementally redistributed in the failed patch. We show that the significant effect of pressure-dependent fluid compressibility in the no in-plane flow case becomes a secondary effect when the other spatial dimensions are considered because in-plane flow with a near-lithostatically pressured neighbourhood equilibrates at a pressure much higher than hydrostatic levels, forming persistent high-pressure fluid compartments. If the observed <span class="hlt">faults</span> are not all overpressured and weak, other mechanisms, not included in this model, must be at work in nature, which need to be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T22D..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T22D..07T"><span>Imaging the North Anatolian <span class="hlt">Fault</span> using the scattered teleseismic wavefield</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, D. A.; Rost, S.; Houseman, G. A.; Cornwell, D. G.; Turkelli, N.; Teoman, U.; Kahraman, M.; Altuncu Poyraz, S.; Gülen, L.; Utkucu, M.; Frederiksen, A. W.; Rondenay, S.</p> <p>2013-12-01</p> <p>The North Anatolian <span class="hlt">Fault</span> Zone (NAFZ) is a major continental strike-slip <span class="hlt">fault</span> system, similar in size and scale to the San Andreas system, that extends ˜1200 km across Turkey. In 2012, a new multidisciplinary project (<span class="hlt">Fault</span>Lab) was instigated to better understand deformation throughout the entire crust in the NAFZ, in particular the expected transition from narrow zones of brittle deformation in the upper crust to possibly broader shear zones in the lower crust/upper mantle and how these features contribute to the earthquake loading cycle. This contribution will discuss the first results from the seismic component of the project, a 73 station network encompassing the northern and southern branches of the NAFZ in the Sakarya region. The Dense Array for North Anatolia (DANA) is arranged as a 6×11 grid with a nominal station spacing of 7 km, with a further 7 stations <span class="hlt">located</span> outside of the main grid. With the excellent resolution afforded by the DANA network, we will present images of crustal structure using the technique of teleseismic scattering tomography. The method uses a full waveform inversion of the teleseismic scattered wavefield coupled with array processing techniques to infer the properties and <span class="hlt">location</span> of small-scale heterogeneities (with scales on the order of the seismic wavelength) within the crust. We will also present preliminary results of teleseismic scattering migration, another powerful method that benefits from the dense data coverage of the deployed seismic network. Images obtained using these methods together with other conventional imaging techniques will provide evidence for how the deformation is distributed within the <span class="hlt">fault</span> zone at depth, providing constraints that can be used in conjunction with structural analyses of exhumed <span class="hlt">fault</span> segments and models of geodetic strain-rate across the <span class="hlt">fault</span> system. By linking together results from the complementary techniques being employed in the <span class="hlt">Fault</span>Lab project, we aim to produce a comprehensive</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMMR33C2680M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMMR33C2680M"><span>Laboratory Evidence of Strength Recovery of Healed <span class="hlt">Faults</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Masuda, K.</p> <p>2015-12-01</p> <p><span class="hlt">Fault</span> zones consist of a <span class="hlt">fault</span> core and a surrounding damage zone. <span class="hlt">Fault</span> zones are typically characterized by the presence of many healed surfaces, the strength of which is unknown. If a healed <span class="hlt">fault</span> recovers its strength such that its cohesion is equal to or greater than that of the host rock, repeated cycles of fracture and healing may be one mechanism producing wide <span class="hlt">fault</span> zones. I present laboratory evidence supporting the strength recovery of healed <span class="hlt">fault</span> surface, obtained by AE monitoring, strain measurements and X-ray CT techniques. The loading experiment was performed with a specimen collected from an exhumed <span class="hlt">fault</span> zone. Healed surfaces of the rock sample were interpreted to be parallel to slip surfaces. The specimen was a cylinder with 50 mm diameter and 100 mm long. The long axis of the specimen was inclined with respect to the orientation of the healed surfaces. The compression test used a constant loading rate under 50 MPa of confining pressure. Macroscopic failure occurred when the applied differential stress reached 439 MPa. The macro-fracture surface created during the experiment was very close to the preexisting plane. The AE hypocenters closely match the <span class="hlt">locations</span> of the preexisting healed surface and the new <span class="hlt">fault</span> plane. The experiment also revealed details of the initial stage of <span class="hlt">fault</span> development. The new <span class="hlt">fault</span> zone developed near, but not precisely on the preexisting healed <span class="hlt">fault</span> plane. An area of heterogeneous structure where stress appears to have concentrated, was where the AEs began, and it was also where the fracture started. This means that the healed surface was not a weak surface and that healing strengthened the <span class="hlt">fault</span> such that its cohesion was equal to or greater than that of the intact host rock. These results suggest that repeated cycles of fracture and healing may be the main mechanism creating wide <span class="hlt">fault</span> zones with multiple <span class="hlt">fault</span> cores and damage zones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMNS21C..10G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMNS21C..10G"><span>Magnetometric and gravimetric surveys in <span class="hlt">fault</span> detection over Acambay System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García-Serrano, A.; Sanchez-Gonzalez, J.; Cifuentes-Nava, G.</p> <p>2013-05-01</p> <p>In commemoration of the centennial of the Acambay intraplate earthquake of November 19th 1912, we carry out gravimetric and magnetometric surveys to define the structure of <span class="hlt">faults</span> caused by this event. The study area is <span class="hlt">located</span> approximately 11 km south of Acambay, in the Acambay-Tixmadeje <span class="hlt">fault</span> system, where we performed two magnetometric surveys, the first consisting of 17 lines with a spacing of 35m between lines and 5m between stations, and the second with a total of 12 lines with the same spacing, both NW. In addition to these two lines we performed gravimetric profiles <span class="hlt">located</span> in the central part of each magnetometric survey, with a spacing of 25m between stations, in order to correlate the results of both techniques, the lengths of such profiles were of 600m and 550m respectively. This work describes the data processing including directional derivatives, analytical signal and inversion, by means of which we obtain results of magnetic variations and anomaly traits highly correlated with those <span class="hlt">faults</span>. It is of great importance to characterize these <span class="hlt">faults</span> given the large population growth in the area and settlement houses on them, which involves a high risk in the security of the population, considering that these are active <span class="hlt">faults</span> and cannot be discard earthquakes associated with them, so it is necessary for the authorities and people have relevant information to these problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JPS...378..646L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JPS...378..646L"><span>Data-driven simultaneous <span class="hlt">fault</span> diagnosis for solid oxide fuel cell system using multi-label pattern identification</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Shuanghong; Cao, Hongliang; Yang, Yupu</p> <p>2018-02-01</p> <p><span class="hlt">Fault</span> diagnosis is a key process for the reliability and safety of solid oxide fuel cell (SOFC) systems. However, it is difficult to rapidly and <span class="hlt">accurately</span> identify <span class="hlt">faults</span> for complicated SOFC systems, especially when simultaneous <span class="hlt">faults</span> appear. In this research, a data-driven Multi-Label (ML) pattern identification approach is proposed to address the simultaneous <span class="hlt">fault</span> diagnosis of SOFC systems. The framework of the simultaneous-<span class="hlt">fault</span> diagnosis primarily includes two components: feature extraction and ML-SVM classifier. The simultaneous-<span class="hlt">fault</span> diagnosis approach can be trained to diagnose simultaneous SOFC <span class="hlt">faults</span>, such as fuel leakage, air leakage in different positions in the SOFC system, by just using simple training data sets consisting only single <span class="hlt">fault</span> and not demanding simultaneous <span class="hlt">faults</span> data. The experimental result shows the proposed framework can diagnose the simultaneous SOFC system <span class="hlt">faults</span> with high accuracy requiring small number training data and low computational burden. In addition, <span class="hlt">Fault</span> Inference Tree Analysis (FITA) is employed to identify the correlations among possible <span class="hlt">faults</span> and their corresponding symptoms at the system component level.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MS%26E..362a2025S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MS%26E..362a2025S"><span>System Analysis by Mapping a <span class="hlt">Fault</span>-tree into a Bayesian-network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheng, B.; Deng, C.; Wang, Y. H.; Tang, L. H.</p> <p>2018-05-01</p> <p>In view of the limitations of <span class="hlt">fault</span> tree analysis in reliability assessment, Bayesian Network (BN) has been studied as an alternative technology. After a brief introduction to the method for mapping a <span class="hlt">Fault</span> Tree (FT) into an equivalent BN, equations used to calculate the structure importance degree, the probability importance degree and the critical importance degree are presented. Furthermore, the correctness of these equations is proved mathematically. Combining with an aircraft landing gear’s FT, an equivalent BN is developed and analysed. The results show that richer and more <span class="hlt">accurate</span> information have been achieved through the BN method than the FT, which demonstrates that the BN is a superior technique in both reliability assessment and <span class="hlt">fault</span> diagnosis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910007729','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910007729"><span>Flight elements: <span class="hlt">Fault</span> detection and <span class="hlt">fault</span> management</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lum, H.; Patterson-Hine, A.; Edge, J. T.; Lawler, D.</p> <p>1990-01-01</p> <p><span class="hlt">Fault</span> management for an intelligent computational system must be developed using a top down integrated engineering approach. An approach proposed includes integrating the overall environment involving sensors and their associated data; design knowledge capture; operations; <span class="hlt">fault</span> detection, identification, and reconfiguration; testability; causal models including digraph matrix analysis; and overall performance impacts on the hardware and software architecture. Implementation of the concept to achieve a real time intelligent <span class="hlt">fault</span> detection and management system will be accomplished via the implementation of several objectives, which are: Development of <span class="hlt">fault</span> tolerant/FDIR requirement and specification from a systems level which will carry through from conceptual design through implementation and mission operations; Implementation of monitoring, diagnosis, and reconfiguration at all system levels providing <span class="hlt">fault</span> isolation and system integration; Optimize system operations to manage degraded system performance through system integration; and Lower development and operations costs through the implementation of an intelligent real time <span class="hlt">fault</span> detection and <span class="hlt">fault</span> management system and an information management system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70100270','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70100270"><span>Steep-dip seismic imaging of the shallow San Andreas <span class="hlt">Fault</span> near Parkfield</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hole, J.A.; Catchings, R.D.; St. Clair, K.C.; Rymer, M.J.; Okaya, D.A.; Carney, B.J.</p> <p>2001-01-01</p> <p>Seismic reflection and refraction images illuminate the San Andreas <span class="hlt">Fault</span> to a depth of 1 kilometer. The prestack depth-migrated reflection image contains near-vertical reflections aligned with the active <span class="hlt">fault</span> trace. The <span class="hlt">fault</span> is vertical in the upper 0.5 kilometer, then dips about 70° to the southwest to at least 1 kilometer subsurface. This dip reconciles the difference between the computed <span class="hlt">locations</span> of earthquakes and the surface <span class="hlt">fault</span> trace. The seismic velocity cross section shows strong lateral variations. Relatively low velocity (10 to 30%), high electrical conductivity, and low density indicate a 1-kilometer-wide vertical wedge of porous sediment or fractured rock immediately southwest of the active <span class="hlt">fault</span> trace.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFMNH53C2012L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFMNH53C2012L"><span>Using the 3D active <span class="hlt">fault</span> model to estimate the surface deformation, a study on HsinChu area, Taiwan.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Y. K.; Ke, M. C.; Ke, S. S.</p> <p>2016-12-01</p> <p>An active <span class="hlt">fault</span> is commonly considered to be active if they have moved one or more times in the last 10,000 years and likely to have another earthquake sometime in the future. The relationship between the <span class="hlt">fault</span> reactivation and the surface deformation after the Chi-Chi earthquake (M=7.2) in 1999 has been concerned up to now. According to the investigations of well-known disastrous earthquakes in recent years, indicated that surface deformation is controlled by the 3D <span class="hlt">fault</span> geometric shape. Because the surface deformation may cause dangerous damage to critical infrastructures, buildings, roads, power, water and gas lines etc. Therefore it's very important to make pre-disaster risk assessment via the 3D active <span class="hlt">fault</span> model to decrease serious economic losses, people injuries and deaths caused by large earthquake. The approaches to build up the 3D active <span class="hlt">fault</span> model can be categorized as (1) field investigation (2) digitized profile data and (3) build the 3D modeling. In this research, we tracked the <span class="hlt">location</span> of the <span class="hlt">fault</span> scarp in the field first, then combined the seismic profiles (had been balanced) and historical earthquake data to build the underground <span class="hlt">fault</span> plane model by using SKUA-GOCAD program. Finally compared the results come from trishear model (written by Richard W. Allmendinger, 2012) and PFC-3D program (Itasca) and got the calculated range of the deformation area. By analysis of the surface deformation area made from Hsin-Chu <span class="hlt">Fault</span>, we concluded the result the damage zone is approaching 68 286m, the magnitude is 6.43, the offset is 0.6m. base on that to estimate the population casualties, building damage by the M=6.43 earthquake in Hsin-Chu area, Taiwan. In the future, in order to be applied <span class="hlt">accurately</span> on earthquake disaster prevention, we need to consider further the groundwater effect and the soil structure interaction inducing by <span class="hlt">faulting</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMNH23C1542C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMNH23C1542C"><span>Shallow <span class="hlt">Faulting</span> in Morelia, Mexico, Based on Seismic Tomography and Geodetically Detected Land Subsidence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cabral-Cano, E.; Arciniega-Ceballos, A.; Vergara-Huerta, F.; Chaussard, E.; Wdowinski, S.; DeMets, C.; Salazar-Tlaczani, L.</p> <p>2013-12-01</p> <p>Subsidence has been a common occurrence in several cities in central Mexico for the past three decades. This process causes substantial damage to the urban infrastructure and housing in several cities and it is a major factor to be considered when planning urban development, land-use zoning and hazard mitigation strategies. Since the early 1980's the city of Morelia in Central Mexico has experienced subsidence associated with groundwater extraction in excess of natural recharge from rainfall. Previous works have focused on the detection and temporal evolution of the subsidence spatial distribution. The most recent InSAR analysis confirms the permanence of previously detected rapidly subsiding areas such as the Rio Grande Meander area and also defines 2 subsidence patches previously undetected in the newly developed suburban sectors west of Morelia at the Fraccionamiento Del Bosque along, south of Hwy. 15 and another patch <span class="hlt">located</span> north of Morelia along Gabino Castañeda del Rio Ave. Because subsidence-induced, shallow <span class="hlt">faulting</span> develops at high horizontal strain localization, newly developed a subsidence areas are particularly prone to <span class="hlt">faulting</span> and fissuring. Shallow <span class="hlt">faulting</span> increases groundwater vulnerability because it disrupts discharge hydraulic infrastructure and creates a direct path for transport of surface pollutants into the underlying aquifer. Other sectors in Morelia that have been experiencing subsidence for longer time have already developed well defined <span class="hlt">faults</span> such as La Colina, Central Camionera, Torremolinos and La Paloma <span class="hlt">faults</span>. Local construction codes in the vicinity of these <span class="hlt">faults</span> define a very narrow swath along which housing construction is not allowed. In order to better characterize these <span class="hlt">fault</span> systems and provide better criteria for future municipal construction codes we have surveyed the La Colina and Torremolinos <span class="hlt">fault</span> systems in the western sector of Morelia using seismic tomographic techniques. Our results indicate that La Colina <span class="hlt">Fault</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T33B2234C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T33B2234C"><span>Repeated <span class="hlt">fault</span> rupture recorded by paleoenvironmental changes in a wetland sedimentary sequence ponded against the Alpine <span class="hlt">Fault</span>, New Zealand</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clark, K.; Berryman, K. R.; Cochran, U. A.; Bartholomew, T.; Turner, G. M.</p> <p>2010-12-01</p> <p>At Hokuri Creek, in south Westland, New Zealand, an 18 m thickness of Holocene sediments has accumulated against the upthrown side of the Alpine <span class="hlt">Fault</span>. Recent fluvial incision has created numerous exposures of this sedimentary sequence. At a decimetre to metre scale there are two dominant types of sedimentary units: clastic-dominated, grey silt packages, and organic-dominated, light brown peaty-silt units. These units represent repeated alternations of the paleoenvironment due to <span class="hlt">fault</span> rupture over the past 7000 years. We have <span class="hlt">located</span> the event horizons within the sedimentary sequence, and identified evidence to support earthquake-driven paleoenvironmental change (rather than climatic variability), and developed a model of paleoenvironmental changes over a typical seismic cycle. To quantitatively characterise the sediments we use high resolution photography, x-ray imaging, magnetic-susceptibility and total carbon analysis. To understand the depositional environment we used diatom and pollen studies. The organic-rich units have very low magnetic susceptibility and density values, with high greyscale and high total carbon values. Diatoms indicate these units represent stable wetland environments with standing water and predominantly in-situ organic material deposition. The clastic-rich units are characterised by higher magnetic susceptibility and density values, with low greyscale and total carbon. The clastic-rich units represent environments of flowing water and deep pond settings that received predominantly catchment-derived silt and sand. The event horizon is <span class="hlt">located</span> at the upper contact of the organic-rich horizons. The event horizon contact marks a drastic change in hydrologic regime as <span class="hlt">fault</span> rupture changed the stream base level and there was a synchronous influx of clastic sediment as the catchment responded to earthquake shaking. During the interseismic period the flowing-water environment gradually stabilised and returned to an organic-rich wetland. Such</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26ES...87i2028T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26ES...87i2028T"><span><span class="hlt">Fault</span> <span class="hlt">location</span> method for unexposed gas trunk line insulation at stray current constant effect area</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsenev, A. N.; Nosov, V. V.; Akimova, E. V.</p> <p>2017-10-01</p> <p>For the purpose of gas trunk lines safe operation, two types of pipe wall metal anticorrosion protection are generally used - the passive (insulation coating) protection and the active (electrochemical) protection. In the process of a pipeline long-term operation, its insulation is subject to wear and damage. Electrochemical protection means of a certain potential value prevent metal dissolution in the soil. When insulation wear and tear attains a level of insufficiency of the protection potential value, the insulating coating needs repair which is a labor-consuming procedure. To reduce the risk of such situation, it is necessary to make inspection rounds to monitor the condition of pipe insulation. A method for pipeline insulation coating unexposed <span class="hlt">fault</span> <span class="hlt">location</span> based on Pearson method is considered, wherein a working cathodic protection station signal of 100 Hz frequency is used, which makes installation of a generator unnecessary, and also a specific generator signal of 1 kHz frequency is used at high noise immunity and sensitivity of the instrument complex. This method enables detection and sizing of unexposed pipeline defects within the zones of earth current permanent action. High noise immunity of selective indicators allows for operation in proximity to 110 kV, 220 kV, and 500 kV power transmission lines in action.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T42A..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T42A..08S"><span>Controls on Patterns of Repeated <span class="hlt">Fault</span> Rupture: Examples From the Denali and Bear River <span class="hlt">Faults</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwartz, D. P.; Hecker, S.</p> <p>2013-12-01</p> <p> was stressed sufficiently to fail at that time. The Bear River <span class="hlt">fault</span> zone (BRFZ) is a young normal <span class="hlt">fault</span> along the eastern margin of basin-range extension that appears to have reactivated a ramp in the Laramide-age Darby-Hogsback thrust. The entire Cenozoic history of the BRFZ may consist of only two surface-rupturing events in the late Holocene (one at ~5 ka and the most recent at ~2.5 ka). The 40-km-long <span class="hlt">fault</span> comprises synthetic and antithetic scarps extending across a zone up to 5 km wide. Remote sensing, including airborne LiDAR, and field studies show that, despite the complexity, the pattern of <span class="hlt">faulting</span> was similar (in <span class="hlt">location</span> and amount) for each of the two events and, at the south end, was strongly influenced by the east-west-trending Uinta Arch. Pre-existing structure clearly has exerted a first-order control on moment release on this immature <span class="hlt">fault</span>. As shown by these examples, data on timing of surface ruptures, coseismic slip, slip rate, and <span class="hlt">fault</span> geometry can provide a basis to constrain lengths of past and future earthquake ruptures, including possible alternative rupture scenarios. The difficult question for hazard analysis is whether the available data capture the full range of behavior and with what relative frequency do the alternatives occur?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFMED21B0274N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFMED21B0274N"><span>The hazard education model in the high school science-club activities above active huge <span class="hlt">fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, R.</p> <p>2017-12-01</p> <p>Along the west coast of pacific ocean, includes Japan, there are huge numerous volcanoes and earthquakes. The biggest cause is their <span class="hlt">location</span> on the border of plates. The pressure among the plates cause strains and cracks. By the island arc lines, strains make long and enormous <span class="hlt">faults</span>. More than huge 150 <span class="hlt">faults</span> are reported (the head quarters for earthquake research promotion, Japan, 2017). Below my working school, it is laying one of the biggest <span class="hlt">faults</span> Nagamachi-Rifu line which is also laying under 1 million population city Sendai. Before 2011 Tohoku earthquake, one of the hugest earthquake was predicted because of the <span class="hlt">fault</span> activities. Investigating the <span class="hlt">fault</span> activity with our school student who live in the closest area is one of the most important hazard education. Therefore, now we are constructing the science club activity with make attention for (1) seeking <span class="hlt">fault</span> line(s) with topographic land maps and on foot search (2) investigate boling core sample soils that was brought in our school founded. (1) Estimate of displacement of the <span class="hlt">faults</span> on foot observation In order to seek the unknown <span class="hlt">fault</span> line in Rifu area, at first it was needed to estimate on the maps(1:25,000 Scale Topographic Maps and Active <span class="hlt">Faults</span> in Urban Area of Map(Sendai), Geographical Survey Institute of Japan). After that estimation, walked over the region with club students to observe slopes which was occurred by the <span class="hlt">faults</span> activation and recorded on the maps. By observant slope gaps, there has a possibilities to have 3 or 4 <span class="hlt">fault</span> lines that are <span class="hlt">located</span> parallel to the known activate <span class="hlt">faults</span>. (2) Investigate of the boling core samples above the <span class="hlt">fault</span>. We investigated 6 columnar-shaped boling core samples which were excavated when the school has been built. The maximum depth of the samples are over 20m, some are new filled sands over original ash tephra and pumice from old volcanoes <span class="hlt">located</span> west direction. In the club activities, we described column diagram of sediments and discussed the sediment</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSV...385...16L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSV...385...16L"><span><span class="hlt">Fault</span> diagnosis of motor bearing with speed fluctuation via angular resampling of transient sound signals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lu, Siliang; Wang, Xiaoxian; He, Qingbo; Liu, Fang; Liu, Yongbin</p> <p>2016-12-01</p> <p>Transient signal analysis (TSA) has been proven an effective tool for motor bearing <span class="hlt">fault</span> diagnosis, but has yet to be applied in processing bearing <span class="hlt">fault</span> signals with variable rotating speed. In this study, a new TSA-based angular resampling (TSAAR) method is proposed for <span class="hlt">fault</span> diagnosis under speed fluctuation condition via sound signal analysis. By applying the TSAAR method, the frequency smearing phenomenon is eliminated and the <span class="hlt">fault</span> characteristic frequency is exposed in the envelope spectrum for bearing <span class="hlt">fault</span> recognition. The TSAAR method can <span class="hlt">accurately</span> estimate the phase information of the <span class="hlt">fault</span>-induced impulses using neither complicated time-frequency analysis techniques nor external speed sensors, and hence it provides a simple, flexible, and data-driven approach that realizes variable-speed motor bearing <span class="hlt">fault</span> diagnosis. The effectiveness and efficiency of the proposed TSAAR method are verified through a series of simulated and experimental case studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JSV...333.3321J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JSV...333.3321J"><span><span class="hlt">Fault</span> identification of rotor-bearing system based on ensemble empirical mode decomposition and self-zero space projection analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Fan; Zhu, Zhencai; Li, Wei; Zhou, Gongbo; Chen, Guoan</p> <p>2014-07-01</p> <p><span class="hlt">Accurately</span> identifying <span class="hlt">faults</span> in rotor-bearing systems by analyzing vibration signals, which are nonlinear and nonstationary, is challenging. To address this issue, a new approach based on ensemble empirical mode decomposition (EEMD) and self-zero space projection analysis is proposed in this paper. This method seeks to identify <span class="hlt">faults</span> appearing in a rotor-bearing system using simple algebraic calculations and projection analyses. First, EEMD is applied to decompose the collected vibration signals into a set of intrinsic mode functions (IMFs) for features. Second, these extracted features under various mechanical health conditions are used to design a self-zero space matrix according to space projection analysis. Finally, the so-called projection indicators are calculated to identify the rotor-bearing system's <span class="hlt">faults</span> with simple decision logic. Experiments are implemented to test the reliability and effectiveness of the proposed approach. The results show that this approach can <span class="hlt">accurately</span> identify <span class="hlt">faults</span> in rotor-bearing systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29214531','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29214531"><span>In situ, <span class="hlt">accurate</span>, surface-enhanced Raman scattering detection of cancer cell nucleus with synchronous <span class="hlt">location</span> by an alkyne-labeled biomolecular probe.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Jing; Liang, Lijia; Guan, Xin; Deng, Rong; Qu, Huixin; Huang, Dianshuai; Xu, Shuping; Liang, Chongyang; Xu, Weiqing</p> <p>2018-01-01</p> <p>A surface-enhanced Raman scattering (SERS) method for in situ detection and analysis of the intranuclear biomolecular information of a cell has been developed based on a small, biocompatible, nuclear-targeting alkyne-tagged deoxyribonucleic acid (DNA) probe (5-ethynyl-2'-deoxyuridine, EDU) that can specially accumulate in the cell nucleus during DNA replications to precisely <span class="hlt">locate</span> the nuclear region without disturbance in cell biological activities and functions. Since the specific alkyne group shows a Raman peak in the Raman-silent region of cells, it is an interior label to visualize the nuclear <span class="hlt">location</span> synchronously in real time when measuring the SERS spectra of a cell. Because no fluorescent-labeled dyes were used for <span class="hlt">locating</span> cell nuclei, this method is simple, nondestructive, non- photobleaching, and valuable for the in situ exploration of vital physiological processes with DNA participation in cell organelles. Graphical abstract A universal strategy was developed to <span class="hlt">accurately</span> <span class="hlt">locate</span> the nuclear region and obtain precise molecular information of cell nuclei by SERS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70030924','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70030924"><span>Quaternary tectonic <span class="hlt">faulting</span> in the Eastern United States</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wheeler, R.L.</p> <p>2006-01-01</p> <p>Paleoseismological study of geologic features thought to result from Quaternary tectonic <span class="hlt">faulting</span> can characterize the frequencies and sizes of large prehistoric and historical earthquakes, thereby improving the accuracy and precision of seismic-hazard assessments. Greater accuracy and precision can reduce the likelihood of both underprotection and unnecessary design and construction costs. Published studies proposed Quaternary tectonic <span class="hlt">faulting</span> at 31 <span class="hlt">faults</span>, folds, seismic zones, and fields of earthquake-induced liquefaction phenomena in the Appalachian Mountains and Coastal Plain. Of the 31 features, seven are of known origin. Four of the seven have nontectonic origins and the other three features are liquefaction fields caused by moderate to large historical and Holocene earthquakes in coastal South Carolina, including Charleston; the Central Virginia Seismic Zone; and the Newbury, Massachusetts, area. However, the causal <span class="hlt">faults</span> of the three liquefaction fields remain unclear. Charleston has the highest hazard because of large Holocene earthquakes in that area, but the hazard is highly uncertain because the earthquakes are uncertainly <span class="hlt">located</span>. Of the 31 features, the remaining 24 are of uncertain origin. They require additional work before they can be clearly attributed either to Quaternary tectonic <span class="hlt">faulting</span> or to nontectonic causes. Of these 24, 14 features, most of them <span class="hlt">faults</span>, have little or no published geologic evidence of Quaternary tectonic <span class="hlt">faulting</span> that could indicate the likely occurrence of earthquakes larger than those observed historically. Three more features of the 24 were suggested to have had Quaternary tectonic <span class="hlt">faulting</span>, but paleoseismological and other studies of them found no evidence of large prehistoric earthquakes. The final seven features of uncertain origin require further examination because all seven are in or near urban areas. They are the Moodus Seismic Zone (Hartford, Connecticut), Dobbs Ferry <span class="hlt">fault</span> zone and Mosholu <span class="hlt">fault</span> (New York</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040085710','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040085710"><span>Composite Bending Box Section Modal Vibration <span class="hlt">Fault</span> Detection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Werlink, Rudy</p> <p>2002-01-01</p> <p>One of the primary concerns with Composite construction in critical structures such as wings and stabilizers is that hidden <span class="hlt">faults</span> and cracks can develop operationally. In the real world, catastrophic sudden failure can result from these undetected <span class="hlt">faults</span> in composite structures. Vibration data incorporating a broad frequency modal approach, could detect significant changes prior to failure. The purpose of this report is to investigate the usefulness of frequency mode testing before and after bending and torsion loading on a composite bending Box Test section. This test article is representative of construction techniques being developed for the recent NASA Blended Wing Body Low Speed Vehicle Project. The Box section represents the construction technique on the proposed blended wing aircraft. Modal testing using an impact hammer provides an frequency fingerprint before and after bending and torsional loading. If a significant structural discontinuity develops, the vibration response is expected to change. The limitations of the data will be evaluated for future use as a non-destructive in-situ method of assessing hidden damage in similarly constructed composite wing assemblies. Modal vibration <span class="hlt">fault</span> detection sensitivity to band-width, <span class="hlt">location</span> and axis will be investigated. Do the sensor accelerometers need to be near the <span class="hlt">fault</span> and or in the same axis? The response data used in this report was recorded at 17 <span class="hlt">locations</span> using tri-axial accelerometers. The modal tests were conducted following 5 independent loading conditions before load to failure and 2 following load to failure over a period of 6 weeks. Redundant data was used to minimize effects from uncontrolled variables which could lead to incorrect interpretations. It will be shown that vibrational modes detected failure at many <span class="hlt">locations</span> when skin de-bonding failures occurred near the center section. Important considerations are the axis selected and frequency range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70068673','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70068673"><span>Aftershocks of the 2010 Mw 7.2 El Mayor-Cucapah earthquake revealcomplex <span class="hlt">faulting</span> in the Yuha Desert, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kroll, K.; Cochran, Elizabeth S.; Richards-Dinger, K.; Sumy, Danielle</p> <p>2013-01-01</p> <p>We detect and precisely <span class="hlt">locate</span> over 9500 aftershocks that occurred in the Yuha Desert region during a 2 month period following the 4 April 2010 Mw 7.2 El Mayor-Cucapah (EMC) earthquake. Events are relocated using a series of absolute and relative relocation procedures that include Hypoinverse, Velest, and hypoDD. <span class="hlt">Location</span> errors are reduced to ~40 m horizontally and ~120 m vertically.Aftershock <span class="hlt">locations</span> reveal a complex pattern of <span class="hlt">faulting</span> with en echelon <span class="hlt">fault</span> segments trending toward the northwest, approximately parallel to the North American-Pacific plate boundary and en echelon, conjugate features trending to the northeast. The relocated seismicity is highly correlated with published surface mapping of <span class="hlt">faults</span> that experienced triggered surface slip in response to the EMC main shock. Aftershocks occurred between 2 km and 11 km depths, consistent with previous studies of seismogenic thickness in the region. Three-dimensional analysis reveals individual and intersecting <span class="hlt">fault</span> planes that are limited in their along-strike length. These <span class="hlt">fault</span> planes remain distinct structures at depth, indicative of conjugate <span class="hlt">faulting</span>, and do not appear to coalesce onto a throughgoing <span class="hlt">fault</span> segment. We observe a complex spatiotemporal migration of aftershocks, with seismicity that jumps between individual <span class="hlt">fault</span> segments that are active for only a few days to weeks. Aftershock rates are roughly consistent with the expected earthquake production rates of Dieterich (1994). The conjugate pattern of <span class="hlt">faulting</span> and nonuniform aftershock migration patterns suggest that strain in the Yuha Desert is being accommodated in a complex manner.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730021606','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730021606"><span>A simulation of the San Andreas <span class="hlt">fault</span> experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Agreen, R. W.; Smith, D. E.</p> <p>1973-01-01</p> <p>The San Andreas <span class="hlt">Fault</span> Experiment, which employs two laser tracking systems for measuring the relative motion of two points on opposite sides of the <span class="hlt">fault</span>, was simulated for an eight year observation period. The two tracking stations are <span class="hlt">located</span> near San Diego on the western side of the <span class="hlt">fault</span> and near Quincy on the eastern side; they are roughly 900 kilometers apart. Both will simultaneously track laser reflector equipped satellites as they pass near the stations. Tracking of the Beacon Explorer C Spacecraft was simulated for these two stations during August and September for eight consecutive years. An error analysis of the recovery of the relative <span class="hlt">location</span> of Quincy from the data was made, allowing for model errors in the mass of the earth, the gravity field, solar radiation pressure, atmospheric drag, errors in the position of the San Diego site, and laser systems range biases and noise. The results of this simulation indicate that the distance of Quincy from San Diego will be determined each year with a precision of about 10 centimeters. This figure is based on the accuracy of earth models and other parameters available in 1972.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T31B2173Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T31B2173Z"><span>Along-strike variations of geometry and kinematics on the border <span class="hlt">fault</span> of Nanpu sag, Bohai Bay Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, C.; Ren, J.; Liu, X.; Sun, Z.; Su, M.</p> <p>2010-12-01</p> <p>Nanpu sag is <span class="hlt">located</span> in the north-eastern portion of the Huanghua depression, covering an area of approximately 1900km2, and comprises one of the most important petroliferous basins of the Bohai Bay Basin. The Nanpu sag is bordered by two master <span class="hlt">faults</span> with long-term activity: the Xi’nanzhuang (XNZ) and Bogezhuang (BGZ) <span class="hlt">fault</span>. By analysis of horizontal slices, gravity anomaly map and seismic reflection sections, we found there is no cutting relationship, and thus considered the XNZ and BGZ <span class="hlt">fault</span> as a same one. However it showed striking differences between the XNZ and BGZ segment in <span class="hlt">fault</span> occurrence, <span class="hlt">fault</span> throw and residual formation thickness and so on. The BGZ <span class="hlt">fault</span> was NW trending <span class="hlt">fault</span> with a steep inclination. Taken section across the northern region in Nanpu sag for example, its controlling depocenter is <span class="hlt">located</span> in eastern subsag (Fig.1); the XNZ <span class="hlt">fault</span> was a NE <span class="hlt">fault</span> and displayed a Shovel-shaped to plate-like geometry, with its controlling depocenter <span class="hlt">located</span> in western subsag. We qualitify the <span class="hlt">fault</span> throw, showing that the XNZ <span class="hlt">fault</span> strongly acted during the sedimentary period of Es3-Es2, while the BGZ <span class="hlt">fault</span> presented weak activity, and especially during Es31 submember-Es2 member, the XNZ <span class="hlt">fault</span> acted so strongly that the hanging wall of BGZ <span class="hlt">fault</span> was tilt-lifted and suffered erosion (Fig.1), which created Es1 uncomformity; The BGZ <span class="hlt">fault</span> acted strongly during the sedimentary period of Es1-Ed, which led the hanging wall of XNZ <span class="hlt">fault</span> to be tilt-lifted. Controlled by such segmented activity of the whole border <span class="hlt">fault</span>, which we suggested a "seesaw" model for its evolution, the northern part in the Nanpu sag experienced an alternative variation between a deposition center and an erosion region after tilt-lifting. Combination of the sediment stacking patterns, we further classified the history of "seesaw" activities into four stages: 1) Early double-break stage (Es35-Es31), both of the XNZ and BGZ <span class="hlt">fault</span> acted; 2) Middle the XNZ segment throw and the BGZ tilting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27889134','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27889134"><span>Neural adaptive observer-based sensor and actuator <span class="hlt">fault</span> detection in nonlinear systems: Application in UAV.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abbaspour, Alireza; Aboutalebi, Payam; Yen, Kang K; Sargolzaei, Arman</p> <p>2017-03-01</p> <p>A new online detection strategy is developed to detect <span class="hlt">faults</span> in sensors and actuators of unmanned aerial vehicle (UAV) systems. In this design, the weighting parameters of the Neural Network (NN) are updated by using the Extended Kalman Filter (EKF). Online adaptation of these weighting parameters helps to detect abrupt, intermittent, and incipient <span class="hlt">faults</span> <span class="hlt">accurately</span>. We apply the proposed <span class="hlt">fault</span> detection system to a nonlinear dynamic model of the WVU YF-22 unmanned aircraft for its evaluation. The simulation results show that the new method has better performance in comparison with conventional recurrent neural network-based <span class="hlt">fault</span> detection strategies. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23690980','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23690980"><span>Error properties of Argos satellite telemetry <span class="hlt">locations</span> using least squares and Kalman filtering.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boyd, Janice D; Brightsmith, Donald J</p> <p>2013-01-01</p> <p>Study of animal movements is key for understanding their ecology and facilitating their conservation. The Argos satellite system is a valuable tool for tracking species which move long distances, inhabit remote areas, and are otherwise difficult to track with traditional VHF telemetry and are not suitable for GPS systems. Previous research has raised doubts about the magnitude of position errors quoted by the satellite service provider CLS. In addition, no peer-reviewed publications have evaluated the usefulness of the CLS supplied error ellipses nor the accuracy of the new Kalman filtering (KF) processing method. Using transmitters hung from towers and trees in southeastern Peru, we show the Argos error ellipses generally contain <25% of the true <span class="hlt">locations</span> and therefore do not adequately describe the true <span class="hlt">location</span> errors. We also find that KF processing does not significantly increase <span class="hlt">location</span> accuracy. The errors for both LS and KF processing methods were found to be lognormally distributed, which has important repercussions for error calculation, statistical analysis, and data interpretation. In brief, "good" positions (<span class="hlt">location</span> codes 3, 2, 1, A) are <span class="hlt">accurate</span> to about 2 km, while 0 and B <span class="hlt">locations</span> are <span class="hlt">accurate</span> to about 5-10 km. However, due to the lognormal distribution of the errors, larger outliers are to be expected in all <span class="hlt">location</span> codes and need to be accounted for in the user's data processing. We evaluate five different empirical error estimates and find that 68% lognormal error ellipses provided the most useful error estimates. Longitude errors are larger than latitude errors by a factor of 2 to 3, supporting the use of elliptical error ellipses. Numerous studies over the past 15 years have also found <span class="hlt">fault</span> with the CLS-claimed error estimates yet CLS has failed to correct their misleading information. We hope this will be reversed in the near future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5021348-fault-born-landers-mojave-earthquake-line','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5021348-fault-born-landers-mojave-earthquake-line"><span>A <span class="hlt">fault</span> is born: The Landers-Mojave earthquake line</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Nur, A.; Ron, H.</p> <p>1993-04-01</p> <p>The epicenter and the southern portion of the 1992 Landers earthquake fell on an approximately N-S earthquake line, defined by both epicentral <span class="hlt">locations</span> and by the rupture directions of four previous M>5 earthquakes in the Mojave: The 1947 Manix; 1975 Galway Lake; 1979 Homestead Valley: and 1992 Joshua Tree events. Another M 5.2 earthquake epicenter in 1965 fell on this line where it intersects the Calico <span class="hlt">fault</span>. In contrast, the northern part of the Landers rupture followed the NW-SE trending Camp Rock and parallel <span class="hlt">faults</span>, exhibiting an apparently unusual rupture kink. The block tectonic model (Ron et al., 1984) combiningmore » <span class="hlt">fault</span> kinematic and mechanics, explains both the alignment of the events, and their ruptures (Nur et al., 1986, 1989), as well as the Landers kink (Nur et al., 1992). Accordingly, the now NW oriented <span class="hlt">faults</span> have rotated into their present direction away from the direction of maximum shortening, close to becoming locked, whereas a new <span class="hlt">fault</span> set, optimally oriented relative to the direction of shortening, is developing to accommodate current crustal deformation. The Mojave-Landers line may thus be a new <span class="hlt">fault</span> in formation. During the transition of <span class="hlt">faulting</span> from the old, well developed and wak but poorly oriented <span class="hlt">faults</span> to the strong, but favorably oriented new ones, both can slip simultaneously, giving rise to kinks such as Landers.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29219563','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29219563"><span>Experimental Demonstration of <span class="hlt">Fault</span>-Tolerant State Preparation with Superconducting Qubits.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takita, Maika; Cross, Andrew W; Córcoles, A D; Chow, Jerry M; Gambetta, Jay M</p> <p>2017-11-03</p> <p>Robust quantum computation requires encoding delicate quantum information into degrees of freedom that are hard for the environment to change. Quantum encodings have been demonstrated in many physical systems by observing and correcting storage errors, but applications require not just storing information; we must <span class="hlt">accurately</span> compute even with faulty operations. The theory of <span class="hlt">fault</span>-tolerant quantum computing illuminates a way forward by providing a foundation and collection of techniques for limiting the spread of errors. Here we implement one of the smallest quantum codes in a five-qubit superconducting transmon device and demonstrate <span class="hlt">fault</span>-tolerant state preparation. We characterize the resulting code words through quantum process tomography and study the free evolution of the logical observables. Our results are consistent with <span class="hlt">fault</span>-tolerant state preparation in a protected qubit subspace.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018SPIE10697E..1RG','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018SPIE10697E..1RG"><span>Encoder <span class="hlt">fault</span> analysis system based on Moire fringe error signal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gao, Xu; Chen, Wei; Wan, Qiu-hua; Lu, Xin-ran; Xie, Chun-yu</p> <p>2018-02-01</p> <p>Aiming at the problem of any <span class="hlt">fault</span> and wrong code in the practical application of photoelectric shaft encoder, a fast and <span class="hlt">accurate</span> encoder <span class="hlt">fault</span> analysis system is researched from the aspect of Moire fringe photoelectric signal processing. DSP28335 is selected as the core processor and high speed serial A/D converter acquisition card is used. And temperature measuring circuit using AD7420 is designed. Discrete data of Moire fringe error signal is collected at different temperatures and it is sent to the host computer through wireless transmission. The error signal quality index and <span class="hlt">fault</span> type is displayed on the host computer based on the error signal identification method. The error signal quality can be used to diagnosis the state of error code through the human-machine interface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.6919K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.6919K"><span>Project DAFNE - Drilling Active <span class="hlt">Faults</span> in Northern Europe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kukkonen, I. T.; Ask, M. S. V.; Olesen, O.</p> <p>2012-04-01</p> <p>We are currently developing a new ICDP project 'Drillling Active <span class="hlt">Faults</span> in Northern Europe' (DAFNE) which aims at investigating, via scientific drilling, the tectonic and structural characteristics of postglacial (PG) <span class="hlt">faults</span> in northern Fennoscandia, including their hydrogeology and associated deep biosphere [1, 2]. During the last stages of the Weichselian glaciation (ca. 9,000 - 15,000 years B.P.), reduced ice load and glacially affected stress field resulted in active <span class="hlt">faulting</span> in Fennoscandia with <span class="hlt">fault</span> scarps up to 160 km long and 30 m high. These postglacial (PG) <span class="hlt">faults</span> are usually SE dipping, SW-NE oriented thrusts, and represent reactivated, pre-existing crustal discontinuities. Postglacial <span class="hlt">faulting</span> indicates that the glacio-isostatic compensation is not only a gradual viscoelastic phenomenon, but includes also unexpected violent earthquakes, suggestively larger than other known earthquakes in stable continental regions. The research is anticipated to advance science in neotectonics, hydrogeology and deep biosphere studies, and provide important information for nuclear waste and CO2 disposal, petroleum exploration on the Norwegian continental shelf and studies of mineral resources in PG <span class="hlt">fault</span> areas. We expect that multidisciplinary research applying shallow and deep drilling of postglacial <span class="hlt">faults</span> would provide significant scientific results through generating new data and models, namely: (1) Understanding PG <span class="hlt">fault</span> genesis and controls of their <span class="hlt">locations</span>; (2) Deep structure and depth extent of PG <span class="hlt">faults</span>; (3) Textural, mineralogical and physical alteration of rocks in the PG <span class="hlt">faults</span>; (4) State of stress and estimates of paleostress of PG <span class="hlt">faults</span>; (5) Hydrogeology, hydrochemistry and hydraulic properties of PG <span class="hlt">faults</span>; (6) Dating of tectonic reactivation(s) and temporal evolution of tectonic systems hosting PG <span class="hlt">faults</span>; (7) Existence/non-existence of deep biosphere in PG <span class="hlt">faults</span>; (8) Data useful for planning radioactive waste disposal in crystalline bedrock; (9) Data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2017/1049/ofr20171049.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2017/1049/ofr20171049.pdf"><span>Eastern Denali <span class="hlt">Fault</span> surface trace map, eastern Alaska and Yukon, Canada</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Bender, Adrian M.; Haeussler, Peter J.</p> <p>2017-05-04</p> <p>We map the 385-kilometer (km) long surface trace of the right-lateral, strike-slip Denali <span class="hlt">Fault</span> between the Totschunda-Denali <span class="hlt">Fault</span> intersection in Alaska, United States and the village of Haines Junction, Yukon, Canada. In Alaska, digital elevation models based on light detection and ranging and interferometric synthetic aperture radar data enabled our <span class="hlt">fault</span> mapping at scales of 1:2,000 and 1:10,000, respectively. Lacking such resources in Yukon, we developed new structure-from-motion digital photogrammetry products from legacy aerial photos to map the <span class="hlt">fault</span> surface trace at a scale of 1:10,000 east of the international border. The section of the <span class="hlt">fault</span> that we map, referred to as the Eastern Denali <span class="hlt">Fault</span>, did not rupture during the 2002 Denali <span class="hlt">Fault</span> earthquake (moment magnitude 7.9). Seismologic, geodetic, and geomorphic evidence, along with a paleoseismic record of past ground-rupturing earthquakes, demonstrate Holocene and contemporary activity on the <span class="hlt">fault</span>, however. This map of the Eastern Denali <span class="hlt">Fault</span> surface trace complements other data sets by providing an openly accessible digital interpretation of the <span class="hlt">location</span>, length, and continuity of the fault’s surface trace based on the accompanying digital topography dataset. Additionally, the digitized <span class="hlt">fault</span> trace may provide geometric constraints useful for modeling earthquake scenarios and related seismic hazard.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/1424887','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/1424887"><span>PV System Component <span class="hlt">Fault</span> and Failure Compilation and Analysis.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Klise, Geoffrey Taylor; Lavrova, Olga; Gooding, Renee Lynne</p> <p></p> <p>This report describes data collection and analysis of solar photovoltaic (PV) equipment events, which consist of <span class="hlt">faults</span> and fa ilures that occur during the normal operation of a distributed PV system or PV power plant. We present summary statistics from <span class="hlt">locations</span> w here maintenance data is being collected at various intervals, as well as reliability statistics gathered from that da ta, consisting of <span class="hlt">fault</span>/failure distributions and repair distributions for a wide range of PV equipment types.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/21590470-accurate-analysis-change-volume-location-shape-metastatic-cervical-lymph-nodes-during-radiotherapy','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/21590470-accurate-analysis-change-volume-location-shape-metastatic-cervical-lymph-nodes-during-radiotherapy"><span><span class="hlt">Accurate</span> Analysis of the Change in Volume, <span class="hlt">Location</span>, and Shape of Metastatic Cervical Lymph Nodes During Radiotherapy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Takao, Seishin, E-mail: takao@mech-me.eng.hokudai.ac.jp; Tadano, Shigeru; Taguchi, Hiroshi</p> <p>2011-11-01</p> <p>Purpose: To establish a method for the <span class="hlt">accurate</span> acquisition and analysis of the variations in tumor volume, <span class="hlt">location</span>, and three-dimensional (3D) shape of tumors during radiotherapy in the era of image-guided radiotherapy. Methods and Materials: Finite element models of lymph nodes were developed based on computed tomography (CT) images taken before the start of treatment and every week during the treatment period. A surface geometry map with a volumetric scale was adopted and used for the analysis. Six metastatic cervical lymph nodes, 3.5 to 55.1 cm{sup 3} before treatment, in 6 patients with head and neck carcinomas were analyzed inmore » this study. Three fiducial markers implanted in mouthpieces were used for the fusion of CT images. Changes in the <span class="hlt">location</span> of the lymph nodes were measured on the basis of these fiducial markers. Results: The surface geometry maps showed convex regions in red and concave regions in blue to ensure that the characteristics of the 3D tumor geometries are simply understood visually. After the irradiation of 66 to 70 Gy in 2 Gy daily doses, the patterns of the colors had not changed significantly, and the maps before and during treatment were strongly correlated (average correlation coefficient was 0.808), suggesting that the tumors shrank uniformly, maintaining the original characteristics of the shapes in all 6 patients. The movement of the gravitational center of the lymph nodes during the treatment period was everywhere less than {+-}5 mm except in 1 patient, in whom the change reached nearly 10 mm. Conclusions: The surface geometry map was useful for an <span class="hlt">accurate</span> evaluation of the changes in volume and 3D shapes of metastatic lymph nodes. The fusion of the initial and follow-up CT images based on fiducial markers enabled an analysis of changes in the <span class="hlt">location</span> of the targets. Metastatic cervical lymph nodes in patients were suggested to decrease in size without significant changes in the 3D shape during radiotherapy. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T31B0629G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T31B0629G"><span>Discovering the Complexity of Capable <span class="hlt">Faults</span> in Northern Chile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, G.; del Río, I. A.; Rojas Orrego, C., Sr.; Astudillo, L. A., Sr.</p> <p>2017-12-01</p> <p>Great crustal earthquakes (Mw >7.0) in the upper plate of subduction zones are relatively uncommon and less well documented. We hypothesize that crustal earthquakes are poorly represented in the instrumental record because they have long recurrence intervals. In northern Chile, the extreme long-term aridity permits extraordinary preservation of landforms related to <span class="hlt">fault</span> activity, making this region a primary target to understand how upper plate <span class="hlt">faults</span> work at subduction zones. To understand how these <span class="hlt">faults</span> relate to crustal seismicity in the long-term, we have conducted a detailed palaeoseismological study. We performed a palaeoseismological survey integrating trench logging and photogrammetry based on UAVs. Optically stimulated luminescence (OSL) age determinations were practiced for dating deposits linked to <span class="hlt">faulting</span>. In this contribution we present the study case of two primary <span class="hlt">faults</span> <span class="hlt">located</span> in the Coastal Cordillera of northern Chile between Iquique (21ºS) and Antofagasta (24ºS). We estimate the maximum moment magnitude of earthquakes generated in these upper plate <span class="hlt">faults</span>, their recurrence interval and the <span class="hlt">fault</span>-slip rate. We conclude that the studied upper plate <span class="hlt">faults</span> show a complex kinematics on geological timescales. <span class="hlt">Faults</span> seem to change their kinematics from normal (extension) to reverse (compression) or from normal to transcurrent (compression) according to the stage of subduction earthquake cycle. Normal displacement is related to coseismic stages and compression is linked to interseismic period. As result this complex interaction these <span class="hlt">faults</span> are capable of generating Mw 7.0 earthquakes, with recurrence times on the order of thousands of years during every stage of the subduction earthquake cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.1615C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.1615C"><span>Salt movements and <span class="hlt">faulting</span> of the overburden - can numerical modeling predict the <span class="hlt">fault</span> patterns above salt structures?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clausen, O. R.; Egholm, D. L.; Wesenberg, R.</p> <p>2012-04-01</p> <p> model is thus an important contribution to the understanding of small-scale <span class="hlt">faults</span>, which may be unresolved by seismic data when the hydrocarbon production from reservoirs <span class="hlt">located</span> above salt structures is optimized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.T21D1847N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.T21D1847N"><span>High Resolution Seismic Imaging of the Trench Canyon <span class="hlt">Fault</span> Zone, Mono Lake, Northeastern California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Novick, M. W.; Jayko, A. S.; Roeske, S.; McClain, J. S.; Hart, P. E.; Boyle, M.</p> <p>2009-12-01</p> <p>High resolution seismic imaging of Mono Lake, <span class="hlt">located</span> in northeastern California, has revealed an approximately northwest striking <span class="hlt">fault</span> in the area to the west of aerially exposed Negit Volcano. This <span class="hlt">fault</span>, henceforth referred to as the Trench Canyon <span class="hlt">Fault</span> (TCF), has also been mapped onshore along a correlating strike as far north as Cedar Hill Volcano, <span class="hlt">located</span> to the northeast of the lake on the California/Nevada border. Onshore, the TCF was mapped for approximately 10 kilometers using air photos, DEM images, and standard geologic pace and compass mapping techniques. The TCF post- dates the last glacial maximum, evidenced by the cutting of wave cut benches along Cedar Hill Volcano. Relict, non-historic shorelines, left by the steady evaporation of Mono Lake beginning approximately 13k, are also repeatedly cut by the <span class="hlt">fault</span>. Additional evidence of <span class="hlt">fault</span> presence includes sag ponds, pressure ridges, tectonically fractured rocks, and normal <span class="hlt">fault</span> scarps found along strike. Offshore, DEM images show a northeast striking structure to the northwest of Negit Volcano, which is co-linear with the onshore TCF. High resolution seismic imaging of the structure, using an applied acoustic/SIG mini-sparker system, reveals steeply dipping Holocene sediments, as well as volcanic deposits from active vents which have erupted in the last 1000 years, offset by the <span class="hlt">fault</span>. Detailed structural analysis of the previously unstudied Trench Canyon <span class="hlt">Fault</span> (TFC) and <span class="hlt">faults</span> in the Cedar Hill region of northern California, along with seismic studies of sediments beneath Mono Lake not only allow for a better comprehension of this minor <span class="hlt">fault</span> system, but provide greater understanding of the larger and more complex Walker Lane Shear Zone. <span class="hlt">Fault</span> analyses, combined and correlated with those from CHV, give a better understanding of how slip is transferred into the complicated Mina defection to the east, from the dextral and normal <span class="hlt">faults</span> along the Sierra Nevada Range front.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T53B2715W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T53B2715W"><span>"The Big One" in Taipei: Numerical Simulation Study of the Sanchiao <span class="hlt">Fault</span> Earthquake Scenarios</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Y.; Lee, S.; Ng, S.</p> <p>2012-12-01</p> <p>Sanchiao <span class="hlt">fault</span> is a western boundary <span class="hlt">fault</span> of the Taipei basin <span class="hlt">located</span> in northern Taiwan, close to the densely populated Taipei metropolitan area. According to the report of Central Geological Survey, the terrestrial portion of the Sanchiao <span class="hlt">fault</span> can be divided into north and south segments. The south segment is about 13 km and north segment is about 21 km. Recent study demonstrated that there are about 40 km of the <span class="hlt">fault</span> trace that extended to the marine area offshore of northern Taiwan. Combined with the marine and terrestrial parts, the total <span class="hlt">fault</span> length of Sanchiao <span class="hlt">fault</span> could be nearly 70 kilometers. Based on the recipe proposed by IRIKURA and Miyake (2010), we estimate the Sanchiao <span class="hlt">fault</span> has the potential to produce an earthquake with moment magnitude larger than Mw 7.2. The total area of <span class="hlt">fault</span> rupture is about 1323 km2, asperity to the total <span class="hlt">fault</span> plane is 22%, and the slips of the asperity and background are 2.8 m and 1.6 m respectively. Use the characteristic source model based on this assumption, the 3D spectral-element method simulation results indicate that Peak ground acceleration (PGA) is significantly stronger along the surface <span class="hlt">fault</span>-rupture. The basin effects play an important role when wave propagates in the Taipei basin which cause seismic wave amplified and prolong the shaking for a very long time. It is worth noting that, when the rupture starts from the southern tip of the <span class="hlt">fault</span>, i.e. the hypocenter <span class="hlt">locates</span> in the basin, the impact of the Sanchiao <span class="hlt">fault</span> earthquake to the Taipei metropolitan area will be the most serious. The strong shaking can cover the entire Taipei city, and even across the basin that extended to eastern-most part of northern Taiwan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EOSTr..94T..96S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EOSTr..94T..96S"><span>Aftershocks to Philippine quake found within nearby megathrust <span class="hlt">fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, Colin</p> <p>2013-02-01</p> <p>On 31 August 2012 a magnitude 7.6 earthquake ruptured deep beneath the sea floor of the Philippine Trench, a powerful intraplate earthquake centered seaward of the plate boundary. In the wake of the main shock, sensors detected a flurry of aftershocks, counting 110 in total. Drawing on seismic wave observations and rupture mechanisms calculated for the aftershocks, Ye et al. found that many were <span class="hlt">located</span> near the epicenter of the main intraplate quake but at shallower depth; all involved normal <span class="hlt">faulting</span>. Some shallow thrusting aftershocks were <span class="hlt">located</span> farther to the west, centered within the potentially dangerous megathrust <span class="hlt">fault</span> formed by the subduction of the Philippine Sea plate beneath the Philippine microplate, the piece of crust housing the Philippine Islands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/985246','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/985246"><span>Development of Hydrologic Characterization Technology of <span class="hlt">Fault</span> Zones -- Phase I, 2nd Report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Karasaki, Kenzi; Onishi, Tiemi; Black, Bill</p> <p>2009-03-31</p> <p>This is the year-end report of the 2nd year of the NUMO-LBNL collaborative project: Development of Hydrologic Characterization Technology of <span class="hlt">Fault</span> Zones under NUMO-DOE/LBNL collaboration agreement, the task description of which can be found in the Appendix 3. Literature survey of published information on the relationship between geologic and hydrologic characteristics of <span class="hlt">faults</span> was conducted. The survey concluded that it may be possible to classify <span class="hlt">faults</span> by indicators based on various geometric and geologic attributes that may indirectly relate to the hydrologic property of <span class="hlt">faults</span>. Analysis of existing information on the Wildcat <span class="hlt">Fault</span> and its surrounding geology was performed. Themore » Wildcat <span class="hlt">Fault</span> is thought to be a strike-slip <span class="hlt">fault</span> with a thrust component that runs along the eastern boundary of the Lawrence Berkeley National Laboratory. It is believed to be part of the Hayward <span class="hlt">Fault</span> system but is considered inactive. Three trenches were excavated at carefully selected <span class="hlt">locations</span> mainly based on the information from the past investigative work inside the LBNL property. At least one <span class="hlt">fault</span> was encountered in all three trenches. Detailed trench mapping was conducted by CRIEPI (Central Research Institute for Electric Power Industries) and LBNL scientists. Some intriguing and puzzling discoveries were made that may contradict with the published work in the past. Predictions are made regarding the hydrologic property of the Wildcat <span class="hlt">Fault</span> based on the analysis of <span class="hlt">fault</span> structure. Preliminary conceptual models of the Wildcat <span class="hlt">Fault</span> were proposed. The Wildcat <span class="hlt">Fault</span> appears to have multiple splays and some low angled <span class="hlt">faults</span> may be part of the flower structure. In parallel, surface geophysical investigations were conducted using electrical resistivity survey and seismic reflection profiling along three lines on the north and south of the LBNL site. Because of the steep terrain, it was difficult to find optimum <span class="hlt">locations</span> for survey lines as it is desirable for them to be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MS%26E..274a2002Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MS%26E..274a2002Y"><span>A <span class="hlt">Fault</span> Recognition System for Gearboxes of Wind Turbines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Zhiling; Huang, Haiyue; Yin, Zidong</p> <p>2017-12-01</p> <p>Costs of maintenance and loss of power generation caused by the <span class="hlt">faults</span> of wind turbines gearboxes are the main components of operation costs for a wind farm. Therefore, the technology of condition monitoring and <span class="hlt">fault</span> recognition for wind turbines gearboxes is becoming a hot topic. A condition monitoring and <span class="hlt">fault</span> recognition system (CMFRS) is presented for CBM of wind turbines gearboxes in this paper. The vibration signals from acceleration sensors at different <span class="hlt">locations</span> of gearbox and the data from supervisory control and data acquisition (SCADA) system are collected to CMFRS. Then the feature extraction and optimization algorithm is applied to these operational data. Furthermore, to recognize the <span class="hlt">fault</span> of gearboxes, the GSO-LSSVR algorithm is proposed, combining the least squares support vector regression machine (LSSVR) with the Glowworm Swarm Optimization (GSO) algorithm. Finally, the results show that the <span class="hlt">fault</span> recognition system used in this paper has a high rate for identifying three states of wind turbines’ gears; besides, the combination of date features can affect the identifying rate and the selection optimization algorithm presented in this paper can get a pretty good date feature subset for the <span class="hlt">fault</span> recognition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=PIA07949&hterms=cutting&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcutting','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=PIA07949&hterms=cutting&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcutting"><span>Cross-Cutting <span class="hlt">Faults</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p><p/> 16 May 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows cross-cutting <span class="hlt">fault</span> scarps among graben features in northern Tempe Terra. Graben form in regions where the crust of the planet has been extended; such features are common in the regions surrounding the vast 'Tharsis Bulge' on Mars. <p/> <i><span class="hlt">Location</span> near</i>: 43.7oN, 90.2oW <i>Image width</i>: 3 km (1.9 mi) <i>Illumination from</i>: lower left <i>Season</i>: Northern Summer</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911966S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911966S"><span>Three dimensional modelling of earthquake rupture cycles on frictional <span class="hlt">faults</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simpson, Guy; May, Dave</p> <p>2017-04-01</p> <p>We are developing an efficient MPI-parallel numerical method to simulate earthquake sequences on preexisting <span class="hlt">faults</span> embedding within a three dimensional viscoelastic half-space. We solve the velocity form of the elasto(visco)dynamic equations using a continuous Galerkin Finite Element Method on an unstructured pentahedral mesh, which thus permits local spatial refinement in the vicinity of the <span class="hlt">fault</span>. Friction sliding is coupled to the viscoelastic solid via rate- and state-dependent friction laws using the split-node technique. Our coupled formulation employs a picard-type non-linear solver with a fully implicit, first order <span class="hlt">accurate</span> time integrator that utilises an adaptive time step that efficiently evolves the system through multiple seismic cycles. The implementation leverages advanced parallel solvers, preconditioners and linear algebra from the Portable Extensible Toolkit for Scientific Computing (PETSc) library. The model can treat heterogeneous frictional properties and stress states on the <span class="hlt">fault</span> and surrounding solid as well as non-planar <span class="hlt">fault</span> geometries. Preliminary tests show that the model successfully reproduces dynamic rupture on a vertical strike-slip <span class="hlt">fault</span> in a half-space governed by rate-state friction with the ageing law.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSG...102..147B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSG...102..147B"><span>How do horizontal, frictional discontinuities affect reverse <span class="hlt">fault</span>-propagation folding?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonanno, Emanuele; Bonini, Lorenzo; Basili, Roberto; Toscani, Giovanni; Seno, Silvio</p> <p>2017-09-01</p> <p>The development of new reverse <span class="hlt">faults</span> and related folds is strongly controlled by the mechanical characteristics of the host rocks. In this study we analyze the impact of a specific kind of anisotropy, i.e. thin mechanical and frictional discontinuities, in affecting the development of reverse <span class="hlt">faults</span> and of the associated folds using physical scaled models. We perform analog modeling introducing one or two initially horizontal, thin discontinuities above an initially blind <span class="hlt">fault</span> dipping at 30° in one case, and 45° in another, and then compare the results with those obtained from a fully isotropic model. The experimental results show that the occurrence of thin discontinuities affects both the development and the propagation of new <span class="hlt">faults</span> and the shape of the associated folds. New <span class="hlt">faults</span> 1) accelerate or decelerate their propagation depending on the <span class="hlt">location</span> of the tips with respect to the discontinuities, 2) cross the discontinuities at a characteristic angle (∼90°), and 3) produce folds with different shapes, resulting not only from the dip of the new <span class="hlt">faults</span> but also from their non-linear propagation history. Our results may have direct impact on future kinematic models, especially those aimed to reconstruct the tectonic history of <span class="hlt">faults</span> that developed in layered rocks or in regions affected by pre-existing <span class="hlt">faults</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.S21C2066U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.S21C2066U"><span>Experimental Modeling of Dynamic Shallow Dip-Slip <span class="hlt">Faulting</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Uenishi, K.</p> <p>2010-12-01</p> <p>In our earlier study (AGU 2005, SSJ 2005, JPGU 2006), using a finite difference technique, we have conducted some numerical simulations related to the source dynamics of shallow dip-slip earthquakes, and suggested the possibility of the existence of corner waves, i.e., shear waves that carry concentrated kinematic energy and generate extremely strong particle motions on the hanging wall of a nonvertical <span class="hlt">fault</span>. In the numerical models, a dip-slip <span class="hlt">fault</span> is <span class="hlt">located</span> in a two-dimensional, monolithic linear elastic half space, and the <span class="hlt">fault</span> plane dips either vertically or 45 degrees. We have investigated the seismic wave field radiated by crack-like rupture of this straight <span class="hlt">fault</span>. If the <span class="hlt">fault</span> rupture, initiated at depth, arrests just below or reaches the free surface, four Rayleigh-type pulses are generated: two propagating along the free surface into the opposite directions to the far field, the other two moving back along the ruptured <span class="hlt">fault</span> surface (interface) downwards into depth. These downward interface pulses may largely control the stopping phase of the dynamic rupture, and in the case the <span class="hlt">fault</span> plane is inclined, on the hanging wall the interface pulse and the outward-moving Rayleigh surface pulse interact with each other and the corner wave is induced. On the footwall, the ground motion is dominated simply by the weaker Rayleigh pulse propagating along the free surface because of much smaller interaction between this Rayleigh and the interface pulse. The generation of the downward interface pulses and corner wave may play a crucial role in understanding the effects of the geometrical asymmetry on the strong motion induced by shallow dip-slip <span class="hlt">faulting</span>, but it has not been well recognized so far, partly because those waves are not expected for a <span class="hlt">fault</span> that is <span class="hlt">located</span> and ruptures only at depth. However, the seismological recordings of the 1999 Chi-Chi, Taiwan, the 2004 Niigata-ken Chuetsu, Japan, earthquakes as well as a more recent one in Iwate-Miyagi Inland</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.H23A1634T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.H23A1634T"><span>Field Injection Test in the Host Rock nearby a <span class="hlt">Fault</span> Zone - Stress Determination and <span class="hlt">Fault</span> Hydraulic Diffusivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsopela, A.; Guglielmi, Y.; Donze, F. V.; De Barros, L.; Henry, P.; Castilla, R.; Gout, C.</p> <p>2017-12-01</p> <p>Fluid injections associated with human activities are well known to induce perturbations in the ambient rock mass. In particular, the hydromechanical response of a nearby <span class="hlt">fault</span> under an increase of the pore pressure is of great interest in permeability as well as seismicity related problems. We present a field injection experiment conducted in the host rock 4m away from a <span class="hlt">fault</span> affecting Toarcian shales (Tournemire massif, France). The site was densely instrumented and during the test the pressure, displacements and seismicity were recorded in order to capture the hydro-mechanical response of the surrounding stimulated volume. A numerical model was used including the reactivated structure at the injection point interacting with a plane representing the main <span class="hlt">fault</span> orientation. A number of calculations were performed in order to estimate the injection characteristics and the state of stress of the test. By making use of the recorded seismic events <span class="hlt">location</span> an attempt is made to reproduce the spatio-temporal characteristics of the microseismicity cloud. We have introduced in the model heterogeneous frictional properties along the <span class="hlt">fault</span> plane that result in flow and rupture channeling effects. Based on the spatio-temporal characteristics of these rupture events we attempt to estimate the resulting hydraulic properties of the <span class="hlt">fault</span> according to the triggering front concept proposed by Shapiro et al. (2002). The effect of the frictional heterogeneities and the <span class="hlt">fault</span> orientation on the resulting hydraulic diffusivity is discussed. We have so far observed in our model that by statistically taking into account the frictional heterogeneities in our analysis, the spatio-temporal characteristics of the rupture events and the recovered hydraulic properties of the <span class="hlt">fault</span> are in a satisfying agreement. References: Shapiro, S. A., Rothert, E., Rath, V., & Rindschwentner, J. (2002). Characterization of fluid transport properties of reservoirs using induced microseismicity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/ds/2006/177/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/ds/2006/177/"><span>Digital Database of Recently Active Traces of the Hayward <span class="hlt">Fault</span>, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lienkaemper, James J.</p> <p>2006-01-01</p> <p>The purpose of this map is to show the <span class="hlt">location</span> of and evidence for recent movement on active <span class="hlt">fault</span> traces within the Hayward <span class="hlt">Fault</span> Zone, California. The mapped traces represent the integration of the following three different types of data: (1) geomorphic expression, (2) creep (aseismic <span class="hlt">fault</span> slip),and (3) trench exposures. This publication is a major revision of an earlier map (Lienkaemper, 1992), which both brings up to date the evidence for <span class="hlt">faulting</span> and makes it available formatted both as a digital database for use within a geographic information system (GIS) and for broader public access interactively using widely available viewing software. The pamphlet describes in detail the types of scientific observations used to make the map, gives references pertaining to the <span class="hlt">fault</span> and the evidence of <span class="hlt">faulting</span>, and provides guidance for use of and limitations of the map. [Last revised Nov. 2008, a minor update for 2007 LiDAR and recent trench investigations; see version history below.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.S53A2823S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.S53A2823S"><span>Modelling of Earthquake History of the Knidos <span class="hlt">Fault</span> Zone SW Turkey Using in-situ 36Cl Surface Exposure Dating by R</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sahin, S.; Yıldırım, C.; Sarıkaya, M. A.; Tuysuz, O.; Genç, S. C.; Aksoy, M. E.; Doksanaltı, M. E.; Benedetti, L.</p> <p>2016-12-01</p> <p>Cosmogenic surface exposure dating is based on the production of rare nuclides in exposed rocks, which interact with cosmic rays. Through modelling of measured 36Cl concentrations, we might obtain information of the history of the earthquake activity. Yet, there are several factors which may impact production of rare nuclides such as geometry of <span class="hlt">fault</span>, topography, geographic <span class="hlt">location</span> of study area, temporal variations of the Earth's magnetic field, self-cover and denudation rate on the scarp. Our study area, the Knidos <span class="hlt">Fault</span> Zone, is <span class="hlt">located</span> on the Datça Peninsula in the Southwestern Anatolia and contains several normal <span class="hlt">fault</span> scarps formed within the limestone, which are appropriate to apply cosmogenic chlorine-36 dating. Since it has a well-preserved scarp, we have focused on the Mezarlık Segment of the <span class="hlt">fault</span> zone, which has an average length of 300 m and height 12-15 m. 128 continuous samples from top to bottom of the <span class="hlt">fault</span> scarp were collected to carry out analysis of cosmic 36Cl isotopes concentrations. Recent research elucidated each step of the application of this method by the Matlab (e.g. Schlagenhauf et al., 2010). It is vitally helpful to generate models activity of normal <span class="hlt">faults</span>. We, however, wanted to build a user-friendly program through an open source programing language R that might be able to help those without knowledge of complex math, programming, making calculations as easy as possible. We have set out to obtain <span class="hlt">accurate</span> conclusions to compare and contrast our results with synthetic profiles and previous studies of limestone <span class="hlt">fault</span> scarps. The preliminary results indicate at least three major or more earthquakes/earthquakes cluster events occurred on the Mezarlık <span class="hlt">fault</span> within the past 20 kyr; over 10 meters of displacement took place between early Holocene and late Pleistocene. Estimated ages of those three large slip events are 18.7, 15.1 and 10.8 ka respectively. This study was conducted with the Decision of the Council of Ministers with No</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S13E..03K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S13E..03K"><span>Multi-<span class="hlt">Fault</span> Rupture Scenarios in the Brawley Seismic Zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kyriakopoulos, C.; Oglesby, D. D.; Rockwell, T. K.; Meltzner, A. J.; Barall, M.</p> <p>2017-12-01</p> <p>Dynamic rupture complexity is strongly affected by both the geometric configuration of a network of <span class="hlt">faults</span> and pre-stress conditions. Between those two, the geometric configuration is more likely to be anticipated prior to an event. An important factor in the unpredictability of the final rupture pattern of a group of <span class="hlt">faults</span> is the time-dependent interaction between them. Dynamic rupture models provide a means to investigate this otherwise inscrutable processes. The Brawley Seismic Zone in Southern California is an area in which this approach might be important for inferring potential earthquake sizes and rupture patterns. Dynamic modeling can illuminate how the main <span class="hlt">faults</span> in this area, the Southern San Andreas (SSAF) and Imperial <span class="hlt">faults</span>, might interact with the intersecting cross <span class="hlt">faults</span>, and how the cross <span class="hlt">faults</span> may modulate rupture on the main <span class="hlt">faults</span>. We perform 3D finite element modeling of potential earthquakes in this zone assuming an extended array of <span class="hlt">faults</span> (Figure). Our results include a wide range of ruptures and <span class="hlt">fault</span> behaviors depending on assumptions about nucleation <span class="hlt">location</span>, geometric setup, pre-stress conditions, and locking depth. For example, in the majority of our models the cross <span class="hlt">faults</span> do not strongly participate in the rupture process, giving the impression that they are not typically an aid or an obstacle to the rupture propagation. However, in some cases, particularly when rupture proceeds slowly on the main <span class="hlt">faults</span>, the cross <span class="hlt">faults</span> indeed can participate with significant slip, and can even cause rupture termination on one of the main <span class="hlt">faults</span>. Furthermore, in a complex network of <span class="hlt">faults</span> we should not preclude the possibility of a large event nucleating on a smaller <span class="hlt">fault</span> (e.g. a cross <span class="hlt">fault</span>) and eventually promoting rupture on the main structure. Recent examples include the 2010 Mw 7.1 Darfield (New Zealand) and Mw 7.2 El Mayor-Cucapah (Mexico) earthquakes, where rupture started on a smaller adjacent segment and later cascaded into a larger</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2007/1103/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2007/1103/"><span>Map and Database of Probable and Possible Quaternary <span class="hlt">Faults</span> in Afghanistan</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ruleman, C.A.; Crone, A.J.; Machette, M.N.; Haller, K.M.; Rukstales, K.S.</p> <p>2007-01-01</p> <p> conjugate shear system in a transpressional region of the Trans-Himalayan orogenic belt. The general patterns and orientations of <span class="hlt">faults</span> and the styles of deformation that we interpret from the imagery are consistent with the styles of <span class="hlt">faulting</span> determined from focal mechanisms of historical earthquakes. Northwest-trending strike-slip <span class="hlt">fault</span> zones are cut and displaced by younger, southeast-verging thrust <span class="hlt">faults</span>; these relations define the interaction between northwest-southeast-oriented contraction and northwest-directed extrusion in the western Himalaya, Pamir, and Hindu Kush regions. Transpression extends into north-central Afghanistan where north-verging contraction along the east-west-trending Alburz-Marmul <span class="hlt">fault</span> system interacts with northwest-trending strike-slip <span class="hlt">faults</span>. Pressure ridges related to thrust <span class="hlt">faulting</span> and extensional basins bounded by normal <span class="hlt">faults</span> are <span class="hlt">located</span> at major stepovers in these northwest-trending strike-slip systems. In contrast, young <span class="hlt">faulting</span> in central and western Afghanistan indicates that the deformation is dominated by extension where strike-slip <span class="hlt">fault</span> zones transition into regions of normal <span class="hlt">faults</span>. In addition to these initial observations, our digital map and database provide a foundation that can be expanded, complemented, and modified as future investigations provide more detailed information about the <span class="hlt">location</span>, characteristics, and history of movement on Quaternary <span class="hlt">faults</span> in Afghanistan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Tectp.728...41C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Tectp.728...41C"><span>Hematite (U-Th)/He thermochronometry constrains intraplate strike-slip <span class="hlt">faulting</span> on the Kuh-e-Faghan <span class="hlt">Fault</span>, central Iran</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Calzolari, Gabriele; Rossetti, Federico; Ault, Alexis K.; Lucci, Federico; Olivetti, Valerio; Nozaem, Reza</p> <p>2018-03-01</p> <p>The Kuh-e-Faghan strike-slip <span class="hlt">fault</span> system (KFF), <span class="hlt">located</span> to the northern edge of the Lut Block in central Iran, developed through a Neogene-Quaternary pulsed history of eastward <span class="hlt">fault</span> propagation and <span class="hlt">fault</span>-related exhumation. This system is a consequence of the residual stresses transmitted from the Arabia-Eurasia convergent plate boundary. Here we integrate structural and textural analysis with new and previously published apatite fission-track (AFT) and apatite (U-Th)/He (apatite He) results, chlorite thermomentry, and hematite (U-Th)/He data from hematite-coated brittle <span class="hlt">fault</span> surfaces to constrain the timing of tectonic activity and refine patterns of late Miocene-Pliocene burial and exhumation associated with the propagation of the KFF. Twenty-nine hematite (U-Th)/He (hematite He) dates from three striated hematite coated slip surfaces from the KFF <span class="hlt">fault</span> core and damage zone yield individual dates from 12-2 Ma. Petrographic analysis and chlorite thermometry of a polyphase, fossil fluid system in the KFF <span class="hlt">fault</span> core document that fluid circulation and mineralization transitioned from a closed system characterized by pressure solution and calcite growth to an open system characterized by hot hydrothermal (T = 239 ± 10 °C) fluids and hematite formation. Hematite microtextures and grain size analysis reveal primary and secondary syntectonic hematite fabrics, no evidence of hematite comminution and similar hematite He closure temperatures ( 60-85 °C) in each sample. Integration of these results with thermal history modeling of AFT and apatite He data shows that KFF activity in the late Miocene is characterized by an early stage of <span class="hlt">fault</span> nucleation, fluid circulation, hematite mineralization, and eastward propagation not associated with vertical movement that lasted from 12 to 7 Ma. Hematite He, AFT, and apatite He data track a second phase of <span class="hlt">fault</span> system activity involving <span class="hlt">fault</span>-related exhumation initiating at 7 Ma and continuing until present time. Our new data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T53A..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T53A..05G"><span>Crustal structure of the Ionian basin and eastern Sicily margin : results from a wide angle seismic survey and implication for the crustal nature and origin of the basin, and the recent tear <span class="hlt">fault</span> <span class="hlt">location</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gutscher, M. A.; Dellong, D.; Klingelhoefer, F.; Kopp, H.; Graindorge, D.; Margheriti, L.; Moretti, M.</p> <p>2017-12-01</p> <p>In the Ionian Sea (Central Mediterranean) the slow convergence between Africa and Eurasia results in the formation of a narrow subduction zone. The nature of the crust and lithosphere of the subducting plate remain debated and could represent the last remnants of the Neo-Tethys ocean. The rifting mechanism that produced the Ionian basin are also still under discussion with the Malta escarpment representing a possible remnant of this opening. At present, this subduction is still retreating to the south-east (motion occurring since the last 35 Ma) but is confined to the narrow Ionian Basin. In order to accommodate slab roll-back, a major lateral slab tear <span class="hlt">fault</span> is required. This <span class="hlt">fault</span> is thought to propagate along the eastern Sicily margin but its precise <span class="hlt">location</span> remains controversial. This study focuses on the deep crustal structure of the Eastern-Sicily margin and the Malta Escarpment by presenting two wide-angle velocity profiles crossing these structures roughly orthogonally. The data used for the forward velocity modeling were acquired onboard the R/V Meteor during the DIONYSUS cruise in 2014. The results image an oceanic crust within the Ionian basin as well as the deep structure of the Malta Escarpment which presents characteristics of a transform margin. A deep and asymmetrical sedimentary basin is imaged south of the Messina strait and seems to have opened in between the Calabrian and Peloritan continental terranes. The interpretation of the velocity models suggests that the tear <span class="hlt">fault</span> is <span class="hlt">located</span> east of the Malta Escarpment, along the Alfeo <span class="hlt">fault</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70042757','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70042757"><span>Why the 2002 Denali <span class="hlt">fault</span> rupture propagated onto the Totschunda <span class="hlt">fault</span>: implications for <span class="hlt">fault</span> branching and seismic hazards</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Schwartz, David P.; Haeussler, Peter J.; Seitz, Gordon G.; Dawson, Timothy E.</p> <p>2012-01-01</p> <p>The propagation of the rupture of the Mw7.9 Denali <span class="hlt">fault</span> earthquake from the central Denali <span class="hlt">fault</span> onto the Totschunda <span class="hlt">fault</span> has provided a basis for dynamic models of <span class="hlt">fault</span> branching in which the angle of the regional or local prestress relative to the orientation of the main <span class="hlt">fault</span> and branch plays a principal role in determining which <span class="hlt">fault</span> branch is taken. GeoEarthScope LiDAR and paleoseismic data allow us to map the structure of the Denali-Totschunda <span class="hlt">fault</span> intersection and evaluate controls of <span class="hlt">fault</span> branching from a geological perspective. LiDAR data reveal the Denali-Totschunda <span class="hlt">fault</span> intersection is structurally simple with the two <span class="hlt">faults</span> directly connected. At the branch point, 227.2 km east of the 2002 epicenter, the 2002 rupture diverges southeast to become the Totschunda <span class="hlt">fault</span>. We use paleoseismic data to propose that differences in the accumulated strain on each <span class="hlt">fault</span> segment, which express differences in the elapsed time since the most recent event, was one important control of the branching direction. We suggest that data on event history, slip rate, paleo offsets, <span class="hlt">fault</span> geometry and structure, and connectivity, especially on high slip rate-short recurrence interval <span class="hlt">faults</span>, can be used to assess the likelihood of branching and its direction. Analysis of the Denali-Totschunda <span class="hlt">fault</span> intersection has implications for evaluating the potential for a rupture to propagate across other types of <span class="hlt">fault</span> intersections and for characterizing sources of future large earthquakes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MS%26E..327b2067K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MS%26E..327b2067K"><span>Product quality management based on CNC machine <span class="hlt">fault</span> prognostics and diagnosis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozlov, A. M.; Al-jonid, Kh M.; Kozlov, A. A.; Antar, Sh D.</p> <p>2018-03-01</p> <p>This paper presents a new <span class="hlt">fault</span> classification model and an integrated approach to <span class="hlt">fault</span> diagnosis which involves the combination of ideas of Neuro-fuzzy Networks (NF), Dynamic Bayesian Networks (DBN) and Particle Filtering (PF) algorithm on a single platform. In the new model, <span class="hlt">faults</span> are categorized in two aspects, namely first and second degree <span class="hlt">faults</span>. First degree <span class="hlt">faults</span> are instantaneous in nature, and second degree <span class="hlt">faults</span> are evolutional and appear as a developing phenomenon which starts from the initial stage, goes through the development stage and finally ends at the mature stage. These categories of <span class="hlt">faults</span> have a lifetime which is inversely proportional to a machine tool's life according to the modified version of Taylor’s equation. For <span class="hlt">fault</span> diagnosis, this framework consists of two phases: the first one is focusing on <span class="hlt">fault</span> prognosis, which is done online, and the second one is concerned with <span class="hlt">fault</span> diagnosis which depends on both off-line and on-line modules. In the first phase, a neuro-fuzzy predictor is used to take a decision on whether to embark Conditional Based Maintenance (CBM) or <span class="hlt">fault</span> diagnosis based on the severity of a <span class="hlt">fault</span>. The second phase only comes into action when an evolving <span class="hlt">fault</span> goes beyond a critical threshold limit called a CBM limit for a command to be issued for <span class="hlt">fault</span> diagnosis. During this phase, DBN and PF techniques are used as an intelligent <span class="hlt">fault</span> diagnosis system to determine the severity, time and <span class="hlt">location</span> of the <span class="hlt">fault</span>. The feasibility of this approach was tested in a simulation environment using the CNC machine as a case study and the results were studied and analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1814458B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1814458B"><span>Towards a <span class="hlt">Fault</span>-based SHA in the Southern Upper Rhine Graben</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baize, Stéphane; Reicherter, Klaus; Thomas, Jessica; Chartier, Thomas; Cushing, Edward Marc</p> <p>2016-04-01</p> <p>A brief overview at a seismic map of the Upper Rhine Graben area (say between Strasbourg and Basel) reveals that the region is seismically active. The area has been hit recently by shallow and moderate quakes but, historically, strong quakes damaged and devastated populated zones. Several authors previously suggested, through preliminary geomorphological and geophysical studies, that active <span class="hlt">faults</span> could be traced along the eastern margin of the graben. Thus, <span class="hlt">fault</span>-based PSHA (probabilistic seismic hazard assessment) studies should be developed. Nevertheless, most of the input data in <span class="hlt">fault</span>-based PSHA models are highly uncertain, based upon sparse or hypothetical data. Geophysical and geological data document the presence of post-Tertiary westward dipping <span class="hlt">faults</span> in the area. However, our first investigations suggest that the available surface <span class="hlt">fault</span> map do not provide a reliable document of Quaternary <span class="hlt">fault</span> traces. Slip rate values that can be currently used in <span class="hlt">fault</span>-PSHA models are based on regional stratigraphic data, but these include neither detailed datings nor clear base surface contours. Several hints on <span class="hlt">fault</span> activity do exist and we have now relevant tools and techniques to figure out the activity of the <span class="hlt">faults</span> of concern. Our preliminary analyses suggest that the LiDAR topography can adequately image the <span class="hlt">fault</span> segments and, thanks to detailed geomorphological analysis, these data allow tracking cumulative <span class="hlt">fault</span> offsets. Because the <span class="hlt">fault</span> models can therefore be considered highly uncertain, our coming project for the next 3 years is to acquire and analyze these <span class="hlt">accurate</span> topographical data, to trace the active <span class="hlt">faults</span> and to determine slip rates through relevant features dating. Eventually, we plan to find a key site to perform a paleoseismological trench because this approach has been proved to be worth in the Graben, both to the North (Wörms and Strasbourg) and to the South (Basel). This would be done in order to definitely prove whether the <span class="hlt">faults</span> ruptured</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JSG....32..693G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JSG....32..693G"><span>Palaeostress perturbations near the El Castillo de las Guardas <span class="hlt">fault</span> (SW Iberian Massif)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García-Navarro, Encarnación; Fernández, Carlos</p> <p>2010-05-01</p> <p>Use of stress inversion methods on <span class="hlt">faults</span> measured at 33 sites <span class="hlt">located</span> at the northwestern part of the South Portuguese Zone (Variscan Iberian Massif), and analysis of the basic dyke attitude at this same region, has revealed a prominent perturbation of the stress trajectories around some large, crustal-scale <span class="hlt">faults</span>, like the El Castillo de las Guardas <span class="hlt">fault</span>. The results are compared with the predictions of theoretical models of palaeostress deviations near master <span class="hlt">faults</span>. According to this comparison, the El Castillo de las Guardas <span class="hlt">fault</span>, an old structure that probably reversed several times its slip sense, can be considered as a sinistral strike-slip <span class="hlt">fault</span> during the Moscovian. These results also point out the main shortcomings that still hinder a rigorous quantitative use of the theoretical models of stress perturbations around major <span class="hlt">faults</span>: the spatial variation in the parameters governing the brittle behaviour of the continental crust, and the possibility of oblique slip along outcrop-scale <span class="hlt">faults</span> in regions subjected to general, non-plane strain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890015446','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890015446"><span>Predeployment validation of <span class="hlt">fault</span>-tolerant systems through software-implemented <span class="hlt">fault</span> insertion</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Czeck, Edward W.; Siewiorek, Daniel P.; Segall, Zary Z.</p> <p>1989-01-01</p> <p><span class="hlt">Fault</span> injection-based automated testing (FIAT) environment, which can be used to experimentally characterize and evaluate distributed realtime systems under <span class="hlt">fault</span>-free and <span class="hlt">faulted</span> conditions is described. A survey is presented of validation methodologies. The need for <span class="hlt">fault</span> insertion based on validation methodologies is demonstrated. The origins and models of <span class="hlt">faults</span>, and motivation for the FIAT concept are reviewed. FIAT employs a validation methodology which builds confidence in the system through first providing a baseline of <span class="hlt">fault</span>-free performance data and then characterizing the behavior of the system with <span class="hlt">faults</span> present. <span class="hlt">Fault</span> insertion is accomplished through software and allows <span class="hlt">faults</span> or the manifestation of <span class="hlt">faults</span> to be inserted by either seeding <span class="hlt">faults</span> into memory or triggering error detection mechanisms. FIAT is capable of emulating a variety of <span class="hlt">fault</span>-tolerant strategies and architectures, can monitor system activity, and can automatically orchestrate experiments involving insertion of <span class="hlt">faults</span>. There is a common system interface which allows ease of use to decrease experiment development and run time. <span class="hlt">Fault</span> models chosen for experiments on FIAT have generated system responses which parallel those observed in real systems under faulty conditions. These capabilities are shown by two example experiments each using a different <span class="hlt">fault</span>-tolerance strategy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1410872B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1410872B"><span>The role of rock anisotropy in developing non-Andersonian <span class="hlt">faults</span>: staircase trajectories for strike-slip <span class="hlt">faults</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barchi, M. R.; Collettini, C.; Lena, G.</p> <p>2012-04-01</p> <p>Thrust and normal <span class="hlt">faults</span> affecting mechanically heterogeneous multilayers often show staircase trajectories, where flat segments follow less competent units. Within flat segments the initiation/reactivation angle, θ, which is the angle that the <span class="hlt">fault</span> makes with the σ1 direction, is different from that predicted by the Andersonian theory. This suggests that <span class="hlt">fault</span> trajectory is mainly controlled by rock anisotropy instead of frictional properties of the material. Our study areas are <span class="hlt">located</span> in the Umbria-Marche fold-thrust belt, within the Northern Apennines of Italy. The area is characterized by a lithologically complex multilayer, about 2000 m thick, consisting of alternated competent (mainly calcareous) and less competent (marls or evaporites) units. At the outcrop scale, some units show a significant mechanical layering, consisting of alternated limestones and shales. Due to the complex tectonic evolution of the Apennines, well developed sets of conjugate normal, thrust and strike-slip <span class="hlt">faults</span> are exposed in the region. The study outcrop, Candigliano Gourge, is characterized by steep (dip > 60°) NE dipping beds, affected by conjugate sets of strike-slip <span class="hlt">faults</span>, exposed in the eastern limb of a NE verging anticline. The <span class="hlt">faults</span> develop within the Marne a Fucoidi Fm., a Cretaceous sedimentary unit, about 70 m thick, made of competent calcareous beds (about 20 cm thick), separated by marly beds (1-20 cm thick). The conjugate strike-slip <span class="hlt">faults</span> are formed after the major folding phase: in fact the strike-slip <span class="hlt">faults</span> cut both minor folds and striated bedding surfaces, related to syn-folding flexural slip. <span class="hlt">Faults</span> show marked staircase trajectories, with straight segments almost parallel to the marly horizons and ramps cutting through the calcareous layers. Slip along these <span class="hlt">faults</span> induces local block rotation of the competent strata, dilational jogs (pull-aparts), extensional duplexes and boudinage of the competent layers, while marly levels are strongly laminated. In</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/80237-strike-slip-faults-moroccan-rif-geophysical-signatures-hydrocarbon-potential','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/80237-strike-slip-faults-moroccan-rif-geophysical-signatures-hydrocarbon-potential"><span>Strike-slip <span class="hlt">faults</span> in the Moroccan Rif: Their geophysical signatures and hydrocarbon potential</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Jobidon, G.P.; Dakki, M.</p> <p>1994-12-31</p> <p>The Rif Domain in Northern Morocco includes major movements along left-lateral strike-slips <span class="hlt">faults</span> that created various structures and influenced depositional systems. The major ones are the Jebha <span class="hlt">fault</span> in the Rif`s northwest area, and the Nekkor <span class="hlt">fault</span> that extends southwesterly from the Mediterranean sea toward the Meseta. Although identified by surface geology in the east, the western extent of the <span class="hlt">faults</span> is ambiguous. Detail interpretation of gravity and magnetic maps provide a better definition of their <span class="hlt">locations</span> and related structures. The Rif`s geology is a mirror image of the right-lateral strike-slip <span class="hlt">fault</span> system of Venezuela and Trinidad. Most features associatedmore » with the Rif`s strike-slip <span class="hlt">faults</span> have not been explored to data and hydrocarbon potential remains a good possibility.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1208736-accurate-modeling-inversion-electrical-resistivity-data-presence-metallic-infrastructure-known-location-dimension','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1208736-accurate-modeling-inversion-electrical-resistivity-data-presence-metallic-infrastructure-known-location-dimension"><span><span class="hlt">Accurate</span> modeling and inversion of electrical resistivity data in the presence of metallic infrastructure with known <span class="hlt">location</span> and dimension</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Johnson, Timothy C.; Wellman, Dawn M.</p> <p>2015-06-26</p> <p>Electrical resistivity tomography (ERT) has been widely used in environmental applications to study processes associated with subsurface contaminants and contaminant remediation. Anthropogenic alterations in subsurface electrical conductivity associated with contamination often originate from highly industrialized areas with significant amounts of buried metallic infrastructure. The deleterious influence of such infrastructure on imaging results generally limits the utility of ERT where it might otherwise prove useful for subsurface investigation and monitoring. In this manuscript we present a method of <span class="hlt">accurately</span> modeling the effects of buried conductive infrastructure within the forward modeling algorithm, thereby removing them from the inversion results. The method ismore » implemented in parallel using immersed interface boundary conditions, whereby the global solution is reconstructed from a series of well-conditioned partial solutions. Forward modeling accuracy is demonstrated by comparison with analytic solutions. Synthetic imaging examples are used to investigate imaging capabilities within a subsurface containing electrically conductive buried tanks, transfer piping, and well casing, using both well casings and vertical electrode arrays as current sources and potential measurement electrodes. Results show that, although <span class="hlt">accurate</span> infrastructure modeling removes the dominating influence of buried metallic features, the presence of metallic infrastructure degrades imaging resolution compared to standard ERT imaging. However, <span class="hlt">accurate</span> imaging results may be obtained if electrodes are appropriately <span class="hlt">located</span>.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..1911259V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..1911259V"><span>Transient cnoidal waves explain the formation and geometry of <span class="hlt">fault</span> damage zones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Veveakis, Manolis; Schrank, Christoph</p> <p>2017-04-01</p> <p>The spatial footprint of a brittle <span class="hlt">fault</span> is usually dominated by a wide area of deformation bands and fractures surrounding a narrow, highly deformed <span class="hlt">fault</span> core. This diffuse damage zone relates to the deformation history of a <span class="hlt">fault</span>, including its seismicity, and has a significant impact on flow and mechanical properties of <span class="hlt">faulted</span> rock. Here, we propose a new mechanical model for damage-zone formation. It builds on a novel mathematical theory postulating fundamental material instabilities in solids with internal mass transfer associated with volumetric deformation due to elastoviscoplastic p-waves termed cnoidal waves. We show that transient cnoidal waves triggered by <span class="hlt">fault</span> slip events can explain the characteristic distribution and extent of deformation bands and fractures within natural <span class="hlt">fault</span> damage zones. Our model suggests that an overpressure wave propagating away from the slipping <span class="hlt">fault</span> and the material properties of the host rock control damage-zone geometry. Hence, cnoidal-wave theory may open a new chapter for predicting seismicity, material and geometrical properties as well as the <span class="hlt">location</span> of brittle <span class="hlt">faults</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T31A0617L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T31A0617L"><span>Deciphering the paleoseismic history of the central Dead Sea <span class="hlt">fault</span> (Yammouneh <span class="hlt">fault</span>, Lebanon) based on multiple luminescence dating techniques</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Le Beon, M.; Tseng, Y. C.; Klinger, Y.; Elias, A.; Kunz, A.; Sursock, A.; Daeron, M.; Tapponnier, P.; Jomaa, R.</p> <p>2017-12-01</p> <p>The Yammouneh <span class="hlt">fault</span> is the main strike-slip branch of the Dead Sea <span class="hlt">fault</span> system in Lebanon. The morphology of the northern Yammouneh <span class="hlt">fault</span> is characterized by a series of basins that represent archives for Late Pleistocene paleo-environments and paleo-earthquakes. We excavated a 4-m-deep trench across the <span class="hlt">fault</span> in the Jbab el-Homr basin that revealed a succession of remarkable, very thin palustrine and lacustrine layers, ruptured by at least 17 earthquakes. Absolute ages of 4 samples from 0.5 to 3.7 m depth are obtained by optically stimulated luminescence dating on fine-grain quartz and on fine-grain K-feldspar using both infrared luminescence at 50˚C (IRSL50) and at a high temperature of 225˚C (pIRIR225). A fair agreement is obtained between the quartz ages (from 26.5 ± 3.1 ka at 0.5 m depth to 30.3 ± 3.4 ka at 3.7 m depth) and the pIRIR225 ages (from 26.2 ± 2.3 ka at 0.5 m depth to 25.8 ± 2.1 ka at 3.7 m depth), while the fading-corrected IRSL50 ages are systematically younger (from 18.3 ± 1.6 ka at 0.5 m depth to 21.4 ± 1.8 ka at 3.7 m depth). As proposed in earlier studies, we hypothesize that the IRSL50 fading rate is underestimated. The sedimentary sequence may reflect deposition in a marsh or shallow lake in a pro-glacial environment at a time when a glacier may have occupied the summits of Mount Lebanon. Erosion may have been dominant after the Last Glacial Maximum. Regarding paleo-earthquakes, 14 surface-rupturing events occurred during 3.8 ka with a mean return time of 270 years and probable clustering, while only 2-11 events occurred since 26.5 ka. Firstly, we explain the lack of events since 26.5 ka by the existence of another <span class="hlt">fault</span> branch, which suggests that the active <span class="hlt">fault</span> zone migrated with time. Secondly, the shorter mean recurrence time in Jbab compared to the Yammouneh site, <span class="hlt">located</span> 30 km south may be explained by temporal variations in the earthquake cycle, different <span class="hlt">locations</span> relative to <span class="hlt">fault</span> segmentation, or by high-resolution of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.T44B..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.T44B..03S"><span>Geometrical and Structural Asperities on <span class="hlt">Fault</span> Surfaces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sagy, A.; Brodsky, E. E.; van der Elst, N.; Agosta, F.; di Toro, G.; Collettini, C.</p> <p>2007-12-01</p> <p>Earthquake dynamics are strongly affected by <span class="hlt">fault</span> zone structure and geometry. <span class="hlt">Fault</span> surface irregularities and the nearby structure control the rupture nucleation and propagation, the <span class="hlt">fault</span> strength, the near-field stress orientations and the hydraulic properties. New field observations demonstrate the existence of asperities in <span class="hlt">faults</span> as displayed by topographical bumps on the <span class="hlt">fault</span> surface and hardening of the internal structure near them. Ground-based LIDAR measurements on more than 30 normal and strike slip <span class="hlt">faults</span> in different lithologies demonstrate that <span class="hlt">faults</span> are not planar surfaces and roughness is strongly dependent on <span class="hlt">fault</span> displacement. In addition to the well-understood roughness exemplified by abrasive striations and fracture segmentation, we found semi-elliptical topographical bumps with wavelengths of a few meters. In many <span class="hlt">faults</span> the bumps are not spread equally on the surface and zones can be bumpier than others. The bumps are most easily identified on <span class="hlt">faults</span> with total displacement of dozens to hundreds of meters. Smaller scale roughness on these <span class="hlt">faults</span> is smoothed by abrasive processes. A key site in southern Oregon shows that the topographic bumps are closely tied to the internal structure of the <span class="hlt">fault</span> zone. At this <span class="hlt">location</span>, we combine LiDAR data with detailed structural analysis of the <span class="hlt">fault</span> zone embedded in volcanic rocks. Here the bumps correlate with an abrupt change in the width of the cohesive cataclasite layer that is exposed under a thin ultracataclasite zone. In most of the exposures the cohesive layer thickness is 10-20 cm. However, under protruding bumps the layer is always thickened and the width can locally exceed one meter. Field and microscopic analyses show that the layer contains grains with dimensions ranging from less than 10 μ up to a few centimeters. There is clear evidence of internal flow, rotation and fracturing of the grains in the layer. X-Ray diffraction measurements of samples from the layer show that the bulk</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010012169&hterms=theory+develop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtheory%2Bdevelop','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010012169&hterms=theory+develop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtheory%2Bdevelop"><span>Robust <span class="hlt">Fault</span> Detection for Aircraft Using Mixed Structured Singular Value Theory and Fuzzy Logic</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Collins, Emmanuel G.</p> <p>2000-01-01</p> <p>The purpose of <span class="hlt">fault</span> detection is to identify when a <span class="hlt">fault</span> or failure has occurred in a system such as an aircraft or expendable launch vehicle. The <span class="hlt">faults</span> may occur in sensors, actuators, structural components, etc. One of the primary approaches to model-based <span class="hlt">fault</span> detection relies on analytical redundancy. That is the output of a computer-based model (actually a state estimator) is compared with the sensor measurements of the actual system to determine when a <span class="hlt">fault</span> has occurred. Unfortunately, the state estimator is based on an idealized mathematical description of the underlying plant that is never totally <span class="hlt">accurate</span>. As a result of these modeling errors, false alarms can occur. This research uses mixed structured singular value theory, a relatively recent and powerful robustness analysis tool, to develop robust estimators and demonstrates the use of these estimators in <span class="hlt">fault</span> detection. To allow qualitative human experience to be effectively incorporated into the detection process fuzzy logic is used to predict the seriousness of the <span class="hlt">fault</span> that has occurred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.S43A2031R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.S43A2031R"><span>The seismic velocity structure of a foreshock zone on an oceanic transform <span class="hlt">fault</span>: Imaging a rupture barrier to the 2008 Mw 6.0 earthquake on the Gofar <span class="hlt">fault</span>, EPR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roland, E. C.; McGuire, J. J.; Lizarralde, D.; Collins, J. A.</p> <p>2010-12-01</p> <p>East Pacific Rise (EPR) oceanic transform <span class="hlt">faults</span> are known to exhibit a number of unique seismicity characteristics, including abundant seismic swarms, a prevalence of aseismic slip, and high rates of foreshock activity. Until recently the details of how this behavior fits into the seismic cycle of large events that occur periodically on transforms have remained poorly understood. In 2008 the most recent seismic cycle of the western segment (G3) of the Gofar <span class="hlt">fault</span> (4 degrees South on the EPR) ended with a Mw 6.0 earthquake. Seismicity associated with this event was recorded by a local array of ocean bottom seismometers, and earthquake <span class="hlt">locations</span> reveal several distinct segments with unique slip behavior on the G3 <span class="hlt">fault</span>. Preceding the Mw 6.0 event, a significant foreshock sequence was recorded just to the east of the mainshock rupture zone that included more than 20,000 detected earthquakes. This foreshock zone formed the eastern barrier to the mainshock rupture, and following the mainshock, seismicity rates within the foreshock zone remained unchanged. Based on aftershock <span class="hlt">locations</span> of events following the 2007 Mw 6.0 event that completed the seismic cycle on the eastern end of the G3 <span class="hlt">fault</span>, it appears that the same foreshock zone may have served as the western rupture barrier for that prior earthquake. Moreover, mainshock rupture associated with each of the last 8 large (~ Mw 6.0) events on the G3 <span class="hlt">fault</span> seems to terminate at the same foreshock zone. In order to elucidate some of the structural controls on <span class="hlt">fault</span> slip and earthquake rupture along transform <span class="hlt">faults</span>, we present a seismic P-wave velocity profile crossing the center of the foreshock zone of the Gofar <span class="hlt">fault</span>, as well as a profile for comparison across the neighboring Quebrada <span class="hlt">fault</span>. Although tectonically similar, Quebrada does not sustain large earthquakes and is thought to accommodate slip primarily aseismically and with small magnitude earthquake swarms. Velocity profiles were obtained using data collected</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2003/ofr-03-451/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2003/ofr-03-451/"><span>Database and Map of Quaternary <span class="hlt">Faults</span> and Folds in Peru and its Offshore Region</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Machare, Jose; Fenton, Clark H.; Machette, Michael N.; Lavenu, Alain; Costa, Carlos; Dart, Richard L.</p> <p>2003-01-01</p> <p>This publication consists of a main map of Quaternary <span class="hlt">faults</span> and fiolds of Peru, a table of Quaternary <span class="hlt">fault</span> data, a region inset map showing relative plate motion, and a second inset map of an enlarged area of interest in southern Peru. These maps and data compilation show evidence for activity of Quaternary <span class="hlt">faults</span> and folds in Peru and its offshore regions of the Pacific Ocean. The maps show the <span class="hlt">locations</span>, ages, and activity rates of major earthquake-related features such as <span class="hlt">faults</span> and <span class="hlt">fault</span>-related folds. These data are accompanied by text databases that describe these features and document current information on their activity in the Quaternary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/hfstudy/modeling-fault-activation-and-seismicity-injection-directly-fault-zone-associated-hydraulic','PESTICIDES'); return false;" href="https://www.epa.gov/hfstudy/modeling-fault-activation-and-seismicity-injection-directly-fault-zone-associated-hydraulic"><span>Modeling of <span class="hlt">fault</span> activation and seismicity by injection directly into a <span class="hlt">fault</span> zone associated with hydraulic fracturing of shale-gas reservoirs</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>LBNL, in consultation with the EPA, expanded upon a previous study by injecting directly into a 3D representation of a hypothetical <span class="hlt">fault</span> zone <span class="hlt">located</span> in the geologic units between the shale-gas reservoir and the drinking water aquifer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.S21A2157C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.S21A2157C"><span>Using focal mechanism solutions to correlate earthquakes with <span class="hlt">faults</span> in the Lake Tahoe-Truckee area, California and Nevada, and to help design LiDAR surveys for active-<span class="hlt">fault</span> reconnaissance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cronin, V. S.; Lindsay, R. D.</p> <p>2011-12-01</p> <p>Geomorphic analysis of hillshade images produced from aerial LiDAR data has been successful in identifying youthful <span class="hlt">fault</span> traces. For example, the recently discovered Polaris <span class="hlt">fault</span> just northwest of Lake Tahoe, California/Nevada, was recognized using LiDAR data that had been acquired by local government to assist land-use planning. Subsequent trenching by consultants under contract to the US Army Corps of Engineers has demonstrated Holocene displacement. The Polaris <span class="hlt">fault</span> is inferred to be capable of generating a magnitude 6.4-6.9 earthquake, based on its apparent length and offset characteristics (Hunter and others, 2011, BSSA 101[3], 1162-1181). Dingler and others (2009, GSA Bull 121[7/8], 1089-1107) describe paleoseismic or geomorphic evidence for late Neogene displacement along other <span class="hlt">faults</span> in the area, including the West Tahoe-Dollar Point, Stateline-North Tahoe, and Incline Village <span class="hlt">faults</span>. We have used the seismo-lineament analysis method (SLAM; Cronin and others, 2008, Env Eng Geol 14[3], 199-219) to establish a tentative spatial correlation between each of the previously mentioned <span class="hlt">faults</span>, as well as with segments of the Dog Valley <span class="hlt">fault</span> system, and one or more earthquake(s). The ~18 earthquakes we have tentatively correlated with <span class="hlt">faults</span> in the Tahoe-Truckee area occurred between 1966 and 2008, with magnitudes between 3 and ~6. Given the focal mechanism solution for a well-<span class="hlt">located</span> shallow-focus earthquake, the nodal planes can be projected to Earth's surface as represented by a DEM, plus-or-minus the vertical and horizontal uncertainty in the focal <span class="hlt">location</span>, to yield two seismo-lineament swaths. The trace of the <span class="hlt">fault</span> that generated the earthquake is likely to be found within one of the two swaths [1] if the <span class="hlt">fault</span> surface is emergent, and [2] if the <span class="hlt">fault</span> surface is approximately planar in the vicinity of the focus. Seismo-lineaments from several of the earthquakes studied overlap in a manner that suggests they are associated with the same <span class="hlt">fault</span>. The surface</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70028373','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70028373"><span>Association of the 1886 Charleston, South Carolina, earthquake and seismicity near Summervile with a 12º bend in the East Coast <span class="hlt">fault</span> system and triple-<span class="hlt">fault</span> junctions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Marple, R.; Miller, R.</p> <p>2006-01-01</p> <p>Seismic-reflection data were integrated with other geophysical, geologic, and seismicity data to better determine the <span class="hlt">location</span> and nature of buried <span class="hlt">faults</span> in the Charleston, South Carolina, region. Our results indicate that the 1886 Charleston, South Carolina, earthquake and seismicity near Summerville are related to local stresses caused by a 12?? bend in the East Coast <span class="hlt">fault</span> system (ECFS) and two triple-<span class="hlt">fault</span> junctions. One triple junction is formed by the intersection of the northwest-trending Ashley River <span class="hlt">fault</span> with the two segments of the ECFS north and south of the bend. The other triple junction is formed by the intersection of the northeast-trending Summerville <span class="hlt">fault</span> and a newly discovered northwest-trending Berkeley <span class="hlt">fault</span> with the ECFS about 10 km north of the bend. The Summerville <span class="hlt">fault</span> is a northwest-dipping border <span class="hlt">fault</span> of the Triassic-age Jedburg basin that is undergoing reverse-style reactivation. This reverse-style reactivation is unusual because the Summerville <span class="hlt">fault</span> parallels the regional stress field axis, suggesting that the reactivation is from stresses applied by dextral motion on the ECFS. The southwest-dip and reverse-type motion of the Berkeley <span class="hlt">fault</span> are interpreted from seismicity data and a seismic-reflection profile in the western part of the study area. Our results also indicate that the East Coast <span class="hlt">fault</span> system is a Paleozoic basement <span class="hlt">fault</span> and that its reactivation since early Mesozoic time has fractured through the overlying allochthonous terranes.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025485','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025485"><span>Imaging the complexity of an active normal <span class="hlt">fault</span> system: The 1997 Colfiorito (central Italy) case study</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chiaraluce, L.; Ellsworth, W.L.; Chiarabba, C.; Cocco, M.</p> <p>2003-01-01</p> <p>Six moderate magnitude earthquakes (5 < Mw < 6) ruptured normal <span class="hlt">fault</span> segments of the southern sector of the North Apennine belt (central Italy) in the 1997 Colfiorito earthquake sequence. We study the progressive activation of adjacent and nearby parallel <span class="hlt">faults</span> of this complex normal <span class="hlt">fault</span> system using ???1650 earthquake <span class="hlt">locations</span> obtained by applying a double-difference <span class="hlt">location</span> method, using travel time picks and waveform cross-correlation measurements. The lateral extent of the <span class="hlt">fault</span> segments range from 5 to 10 km and make up a broad, ???45 km long, NW trending <span class="hlt">fault</span> system. The geometry of each segment is quite simple and consists of planar <span class="hlt">faults</span> gently dipping toward SW with an average dip of 40??-45??. The <span class="hlt">fault</span> planes are not listric but maintain a constant dip through the entire seismogenic volume, down to 8 km depth. We observe the activation of <span class="hlt">faults</span> on the hanging wall and the absence of seismicity in the footwall of the structure. The observed <span class="hlt">fault</span> segmentation appears to be due to the lateral heterogeneity of the upper crust: preexisting thrusts inherited from Neogene's compressional tectonic intersect the active normal <span class="hlt">faults</span> and control their maximum length. The stress tensor obtained by inverting the six main shock focal mechanisms of the sequence is in agreement with the tectonic stress active in the inner chain of the Apennine, revealing a clear NE trending extension direction. Aftershock focal mechanisms show a consistent extensional kinematics, 70% of which are mechanically consistent with the main shock stress field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2010/1010/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2010/1010/"><span>The Quaternary Silver Creek <span class="hlt">Fault</span> Beneath the Santa Clara Valley, California</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wentworth, Carl M.; Williams, Robert A.; Jachens, Robert C.; Graymer, Russell W.; Stephenson, William J.</p> <p>2010-01-01</p> <p> a negative flower structure. This structure implies some continuing strike slip on the Silver Creek <span class="hlt">Fault</span> in the late Quaternary as well, with a transtensional component but no dip slip. Our only basis for estimating the rate of this later Quaternary strike slip on the Silver Creek <span class="hlt">Fault</span> is to assume continuation of the inferred early Quaternary rate of less than 2 mm/yr. <span class="hlt">Faulting</span> evident in a detailed seismic reflection profile across the Silver Creek <span class="hlt">Fault</span> extends up to the limit of data at a depth of 50 m and age of about 140 ka, and the course of Coyote Creek suggests Holocene capture in a structural depression along the <span class="hlt">fault</span>. No surface trace is evident on the alluvial plain, however, and convincing evidence of Holocene offset is lacking. Few instrumentally recorded earthquakes are <span class="hlt">located</span> near the <span class="hlt">fault</span>, and those that are near its southern end represent cross-<span class="hlt">fault</span> shortening, not strike slip. The <span class="hlt">fault</span> might have been responsible, however, for two poorly <span class="hlt">located</span> moderate earthquakes that occurred in the area in 1903. Its southeastern end does mark an abrupt change in the pattern of abundant instrumentally recorded earthquakes along the Calaveras <span class="hlt">Fault</span>-in both its strike and in the depth distribution of hypocenters-that could indicate continuing influence by the Silver Creek <span class="hlt">Fault</span>. In the absence of convincing evidence to the contrary, and as a conservative estimate, we presume that the Silver Creek <span class="hlt">Fault</span> has continued its strike-slip movement through the Holocene, but at a very slow rate. Such a slow rate would, at most, yield very infrequent damaging earthquakes. If the 1903 earthquakes did, in fact, occur on the Silver Creek <span class="hlt">Fault</span>, they would have greatly reduced the short-term future potential for large earthquakes on the <span class="hlt">fault</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.bssaonline.org/content/100/3/1031.short','USGSPUBS'); return false;" href="http://www.bssaonline.org/content/100/3/1031.short"><span>Seismotectonics and <span class="hlt">fault</span> structure of the California Central Coast</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hardebeck, Jeanne L.</p> <p>2010-01-01</p> <p>I present and interpret new earthquake relocations and focal mechanisms for the California Central Coast. The relocations improve upon catalog <span class="hlt">locations</span> by using 3D seismic velocity models to account for lateral variations in structure and by using relative arrival times from waveform cross-correlation and double-difference methods to image seismicity features more sharply. Focal mechanisms are computed using ray tracing in the 3D velocity models. Seismicity alignments on the Hosgri <span class="hlt">fault</span> confirm that it is vertical down to at least 12 km depth, and the focal mechanisms are consistent with right-lateral strike-slip motion on a vertical <span class="hlt">fault</span>. A prominent, newly observed feature is an ~25 km long linear trend of seismicity running just offshore and parallel to the coastline in the region of Point Buchon, informally named the Shoreline <span class="hlt">fault</span>. This seismicity trend is accompanied by a linear magnetic anomaly, and both the seismicity and the magnetic anomaly end where they obliquely meet the Hosgri <span class="hlt">fault</span>. Focal mechanisms indicate that the Shoreline <span class="hlt">fault</span> is a vertical strike-slip <span class="hlt">fault</span>. Several seismicity lineations with vertical strike-slip mechanisms are observed in Estero Bay. Events greater than about 10 km depth in Estero Bay, however, exhibit reverse-<span class="hlt">faulting</span> mechanisms, perhaps reflecting slip at the top of the remnant subducted slab. Strike-slip mechanisms are observed offshore along the Hosgri–San Simeon <span class="hlt">fault</span> system and onshore along the West Huasna and Rinconada <span class="hlt">faults</span>, while reverse mechanisms are generally confined to the region between these two systems. This suggests a model in which the reverse <span class="hlt">faulting</span> is primarily due to restraining left-transfer of right-lateral slip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511547R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511547R"><span>High resolution t-LiDAR scanning of an active bedrock <span class="hlt">fault</span> scarp for palaeostress analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reicherter, Klaus; Wiatr, Thomas; Papanikolaou, Ioannis; Fernández-Steeger, Tomas</p> <p>2013-04-01</p> <p>Palaeostress analysis of an active bedrock normal <span class="hlt">fault</span> scarp based on kinematic indicators is carried applying terrestrial laser scanning (t-LiDAR or TLS). For this purpose three key elements are necessary for a defined region on the <span class="hlt">fault</span> plane: (i) the orientation of the <span class="hlt">fault</span> plane, (ii) the orientation of the slickenside lineation or other kinematic indicators and (iii) the sense of motion of the hanging wall. We present a workflow to obtain palaeostress data from point cloud data using terrestrial laser scanning. The entire case-study was performed on a continuous limestone bedrock normal <span class="hlt">fault</span> scarp on the island of Crete, Greece, at four different <span class="hlt">locations</span> along the WNW-ESE striking Spili <span class="hlt">fault</span>. At each <span class="hlt">location</span> we collected data with a mobile terrestrial light detection and ranging system and validated the calculated three-dimensional palaeostress results by comparison with the conventional palaeostress method with compass at three of the <span class="hlt">locations</span>. Numerous kinematics indicators for normal <span class="hlt">faulting</span> were discovered on the <span class="hlt">fault</span> plane surface using t-LiDAR data and traditional methods, like Riedel shears, extensional break-outs, polished corrugations and many more. However, the kinematic indicators are more or less unidirectional and almost pure dip-slip. No oblique reactivations have been observed. But, towards the tips of the <span class="hlt">fault</span>, inclination of the striation tends to point towards the centre of the <span class="hlt">fault</span>. When comparing all reconstructed palaeostress data obtained from t-LiDAR to that obtained through manual compass measurements, the degree of <span class="hlt">fault</span> plane orientation divergence is around ±005/03 for dip direction and dip. The degree of slickenside lineation variation is around ±003/03 for dip direction and dip. Therefore, the percentage threshold error of the individual vector angle at the different investigation site is lower than 3 % for the dip direction and dip for planes, and lower than 6 % for strike. The maximum mean variation of the complete</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.T21C0441F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.T21C0441F"><span>Structural Analysis of the Exhumed SEMP <span class="hlt">Fault</span> Zone, Austria: Towards an Understanding of <span class="hlt">Fault</span> Zone Architecture Throughout the Seismogenic Crust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Frost, E. K.; Dolan, J. F.; Sammis, C.; Hacker, B.; Ratschbacher, L.</p> <p>2006-12-01</p> <p>One of the most exciting and important frontiers in earthquake science is the linkage between the internal structure and the mechanical behavior of <span class="hlt">fault</span> zones. In particular, little is known about how <span class="hlt">fault</span>-zone structure varies as a function of depth, from near-surface conditions down through the seismogenic crust and into the ductile lower crust. Such understanding is vital if we are to understand the mechanical instabilities that control the nucleation and propagation of seismic ruptures. This imperative has led us to the Oligo-Miocene Salzach-Ennstal-Mariazell-Puchberg [SEMP] <span class="hlt">fault</span> zone in Austria, a major left-lateral strike-slip <span class="hlt">fault</span> that has been exhumed differentially such that it exposes a continuum of structural levels along strike. This exhumed <span class="hlt">fault</span> system provides a unique opportunity to systematically examine depth-dependent changes in <span class="hlt">fault</span>-zone geometry and structure along a single <span class="hlt">fault</span>. In order to establish the structure of the <span class="hlt">fault</span> zone in the seismogenic crust, we are studying exposures of this <span class="hlt">fault</span> at a variety of exhumation levels, from <1 km near the eastern end of the <span class="hlt">fault</span>, downward through the seismogenic crust, across the brittle-ductile transition, and into the uppermost part of the lower crust in western Austria. Here we present our results from one of these study sites, a spectacular exposure of the <span class="hlt">fault</span> zone near the town of Gstatterboden in central Austria. The <span class="hlt">fault</span>, which at this <span class="hlt">location</span> has been exhumed from a depth of ~ 2-3 km, juxtaposes limestone of the Wettersteinkalk on the south with dolomite of the Ramsaudolomit on the north. We conducted two detailed structural traverses over a <span class="hlt">fault</span>-perpendicular width of over 200 m. Analysis of the density and orientation of outcrop scale features, such as <span class="hlt">faults</span> and fractures, reveals a highly asymmetric pattern of <span class="hlt">fault</span> zone damage. Dolomite to the north of the <span class="hlt">fault</span> is extensively shattered, while the limestone unit to the south shows only minor evidence of <span class="hlt">fault</span> damage</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018MS%26E..294a2074I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018MS%26E..294a2074I"><span>Study of a phase-to-ground <span class="hlt">fault</span> on a 400 kV overhead transmission line</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iagăr, A.; Popa, G. N.; Diniş, C. M.</p> <p>2018-01-01</p> <p>Power utilities need to supply their consumers at high power quality level. Because the <span class="hlt">faults</span> that occur on High-Voltage and Extra-High-Voltage transmission lines can cause serious damages in underlying transmission and distribution systems, it is important to examine each <span class="hlt">fault</span> in detail. In this work we studied a phase-to-ground <span class="hlt">fault</span> (on phase 1) of 400 kV overhead transmission line Mintia-Arad. Indactic® 650 <span class="hlt">fault</span> analyzing system was used to record the history of the <span class="hlt">fault</span>. Signals (analog and digital) recorded by Indactic® 650 were visualized and analyzed by Focus program. Summary of <span class="hlt">fault</span> report allowed evaluation of behavior of control and protection equipment and determination of cause and <span class="hlt">location</span> of the <span class="hlt">fault</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T22A..01M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T22A..01M"><span>Finding <span class="hlt">Faults</span>: Tohoku and other Active Megathrusts/Megasplays</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, J. C.; Conin, M.; Cook, B. J.; Kirkpatrick, J. D.; Remitti, F.; Chester, F.; Nakamura, Y.; Lin, W.; Saito, S.; Scientific Team, E.</p> <p>2012-12-01</p> <p>Current subduction-<span class="hlt">fault</span> drilling procedure is to drill a logging hole, identify target <span class="hlt">faults</span>, then core and instrument them. Seismic data may constrain <span class="hlt">faults</span> but the additional resolution of borehole logs is necessary for efficient coring and instrumentation under difficult conditions and tight schedules. Thus, refining the methodology of identifying <span class="hlt">faults</span> in logging data has become important, and thus comparison of log signatures of <span class="hlt">faults</span> in different <span class="hlt">locations</span> is worthwhile. At the C0019 (JFAST) drill site, the Tohoku megathrust was principally identified as a decollement where steep cylindrically-folded bedding abruptly flattens below the basal detachment. A similar structural contrast occurs across a megasplay <span class="hlt">fault</span> in the NanTroSEIZE transect (Site C0004). At the Tohoku decollement, a high gamma-ray value from a pelagic clay layer, predicted as a likely decollement sediment type, strengthens the megathrust interpretation. The original identification of the pelagic clay as a decollement candidate was based on results of previous coring of an oceanic reference site. Negative density anomalies, often seen as low resistivity zones, identified a subsidiary <span class="hlt">fault</span> in the deformed prism overlying the Tohoku megathrust. Elsewhere, at Barbados, Nankai (Moroto), and Costa Rica, negative density anomalies are associated with the decollement and other <span class="hlt">faults</span> in hanging walls. Log-based density anomalies in <span class="hlt">fault</span> zones provide a basis for recognizing in-situ <span class="hlt">fault</span> zone dilation. At the Tohoku Site C0019, breakouts are present above but not below the megathrust. Changes in breakout orientation and width (stress magnitude) occur across megasplay <span class="hlt">faults</span> at Sites C0004 and C0010 in the NantroSEIZE transect. Annular pressure anomalies are not apparent at the Tohoku megathrust, but are variably associated with <span class="hlt">faults</span> and fracture zones drilled along the NanTroSEIZE transect. Overall, images of changes in structural features, negative density anomalies, and changes in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3574731','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3574731"><span>Customized Multiwavelets for Planetary Gearbox <span class="hlt">Fault</span> Detection Based on Vibration Sensor Signals</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sun, Hailiang; Zi, Yanyang; He, Zhengjia; Yuan, Jing; Wang, Xiaodong; Chen, Lue</p> <p>2013-01-01</p> <p>Planetary gearboxes exhibit complicated dynamic responses which are more difficult to detect in vibration signals than fixed-axis gear trains because of the special gear transmission structures. Diverse advanced methods have been developed for this challenging task to reduce or avoid unscheduled breakdown and catastrophic accidents. It is feasible to make <span class="hlt">fault</span> features distinct by using multiwavelet denoising which depends on the feature separation and the threshold denoising. However, standard and fixed multiwavelets are not suitable for <span class="hlt">accurate</span> <span class="hlt">fault</span> feature detections because they are usually independent of the measured signals. To overcome this drawback, a method to construct customized multiwavelets based on the redundant symmetric lifting scheme is proposed in this paper. A novel indicator which combines kurtosis and entropy is applied to select the optimal multiwavelets, because kurtosis is sensitive to sharp impulses and entropy is effective for periodic impulses. The improved neighboring coefficients method is introduced into multiwavelet denoising. The vibration signals of a planetary gearbox from a satellite communication antenna on a measurement ship are captured under various motor speeds. The results show the proposed method could <span class="hlt">accurately</span> detect the incipient pitting <span class="hlt">faults</span> on two neighboring teeth in the planetary gearbox. PMID:23334609</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70048550','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70048550"><span>InSAR Evidence for an active shallow thrust <span class="hlt">fault</span> beneath the city of Spokane Washington, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wicks, Charles W.; Weaver, Craig S.; Bodin, Paul; Sherrod, Brian</p> <p>2013-01-01</p> <p>In 2001, a nearly five month long sequence of shallow, mostly small magnitude earthquakes occurred beneath the city of Spokane, a city with a population of about 200,000, in the state of Washington. During most of the sequence, the earthquakes were not well <span class="hlt">located</span> because seismic instrumentation was sparse. Despite poor-quality <span class="hlt">locations</span>, the earthquake hypocenters were likely very shallow, because residents near the city center both heard and felt many of the earthquakes. The combination of poor earthquake <span class="hlt">locations</span> and a lack of known surface <span class="hlt">faults</span> with recent movement make assessing the seismic hazards related to the earthquake swarm difficult. However, the potential for destruction from a shallow moderate-sized earthquake is high, for example Christchurch New Zealand in 2011, so assessing the hazard potential of a seismic structure involved in the Spokane earthquake sequence is important. Using interferometric synthetic aperture radar (InSAR) data from the European Space Agency ERS2 and ENVISAT satellites and the Canadian Space Agency RADARSAT-1, satellite we are able to show that slip on a shallow previously unknown thrust <span class="hlt">fault</span>, which we name the Spokane <span class="hlt">Fault</span>, is the source of the earthquake sequence. The part of the Spokane <span class="hlt">Fault</span> that slipped during the 2001 earthquake sequence underlies the north part of the city, and slip on the <span class="hlt">fault</span> was concentrated between ~0.3 and 2 km depth. Projecting the buried <span class="hlt">fault</span> plane to the surface gives a possible surface trace for the Spokane <span class="hlt">Fault</span> that strikes northeast from the city center into north Spokane.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1513800L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1513800L"><span>Development of fluid overpressures in crustal <span class="hlt">faults</span> and implications for earthquakes mechanics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leclère, Henri; Cappa, Frédéric; Faulkner, Daniel; Armitage, Peter; Blake, Oshaine; Fabbri, Olivier</p> <p>2013-04-01</p> <p>The development and maintenance of fluid overpressures strongly influence the mechanical behavior of the crust and especially crustal <span class="hlt">fault</span> zones. The mechanisms allowing fluid pressure build-up are still open questions, and their influence on tectonic and <span class="hlt">fault</span> weakening processes remain unclear. The determination of the hydraulic and mechanical properties of crustal <span class="hlt">fault</span> zone elements is a key aspect to improve our understanding of the fluid-tectonic interactions and more particularly the role of fluids in <span class="hlt">fault</span> mechanics and earthquake triggering. Here we address this question combining geological observations, laboratory experiments and hydromechanical models of an active crustal <span class="hlt">fault</span>-zone in the Ubaye-Argentera area (southeastern France). Previous studies showed that the fluids <span class="hlt">located</span> in the <span class="hlt">fault</span> zone developed overpressures between 7 and 26 MPa, that triggered intense seismic swarms (i.e. 16,000 events in 2003-2004) (Jenatton et al., 2007; Daniel et al., 2011; Leclère et al., 2012). The <span class="hlt">fault</span>-zone studied here is <span class="hlt">located</span> in the Argentera external crystalline massif and is connected to regional NW-SE steeply-dipping dextral strike-slip <span class="hlt">faults</span> with an offset of several kilometers. The <span class="hlt">fault</span> zone cuts through migmatitic gneisses composed of quartz, K-feldspar, plagioclase, biotite and minor muscovite. It exposes several anastomosed core zones surrounded by damage zones with a pluri-decametric total width. The core zones are made up of centimetric to pluridecimetric phyllosilicate-rich gouge layers while the damage zones are composed of pluri-metric phyllonitic rock derived from mylonite. The permeability and elastic moduli of the host rock, damage zone and <span class="hlt">fault</span> core were measured from plugs with a diameter of 20 mm and lengths between 26 to 51 mm, using a high-pressure hydrostatic fluid-flow apparatus. Measurements were made with confining pressures ranging from 30 to 210 MPa and using argon pore fluid pressure of 20 MPa. Data show a variation of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Tectp.733..193Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Tectp.733..193Y"><span>Rupture preparation process controlled by surface roughness on meter-scale laboratory <span class="hlt">fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamashita, Futoshi; Fukuyama, Eiichi; Xu, Shiqing; Mizoguchi, Kazuo; Kawakata, Hironori; Takizawa, Shigeru</p> <p>2018-05-01</p> <p>We investigate the effect of <span class="hlt">fault</span> surface roughness on rupture preparation characteristics using meter-scale metagabbro specimens. We repeatedly conducted the experiments with the same pair of rock specimens to make the <span class="hlt">fault</span> surface rough. We obtained three experimental results under the same experimental conditions (6.7 MPa of normal stress and 0.01 mm/s of loading rate) but at different roughness conditions (smooth, moderately roughened, and heavily roughened). During each experiment, we observed many stick-slip events preceded by precursory slow slip. We investigated when and where slow slip initiated by using the strain gauge data processed by the Kalman filter algorithm. The observed rupture preparation processes on the smooth <span class="hlt">fault</span> (i.e. the first experiment among the three) showed high repeatability of the spatiotemporal distributions of slow slip initiation. Local stress measurements revealed that slow slip initiated around the region where the ratio of shear to normal stress (τ/σ) was the highest as expected from finite element method (FEM) modeling. However, the exact <span class="hlt">location</span> of slow slip initiation was where τ/σ became locally minimum, probably due to the frictional heterogeneity. In the experiment on the moderately roughened <span class="hlt">fault</span>, some irregular events were observed, though the basic characteristics of other regular events were similar to those on the smooth <span class="hlt">fault</span>. Local stress data revealed that the spatiotemporal characteristics of slow slip initiation and the resulting τ/σ drop for irregular events were different from those for regular ones even under similar stress conditions. On the heavily roughened <span class="hlt">fault</span>, the <span class="hlt">location</span> of slow slip initiation was not consistent with τ/σ anymore because of the highly heterogeneous static friction on the <span class="hlt">fault</span>, which also decreased the repeatability of spatiotemporal distributions of slow slip initiation. These results suggest that <span class="hlt">fault</span> surface roughness strongly controls the rupture preparation process</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.9256H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.9256H"><span>Fluid flow and permeabilities in basement <span class="hlt">fault</span> zones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hollinsworth, Allan; Koehn, Daniel</p> <p>2017-04-01</p> <p><span class="hlt">Fault</span> zones are important sites for crustal fluid flow, specifically where they cross-cut low permeability host rocks such as granites and gneisses. Fluids migrating through <span class="hlt">fault</span> zones can cause rheology changes, mineral precipitation and pore space closure, and may alter the physical and chemical properties of the host rock and deformation products. It is therefore essential to consider the evolution of permeability in <span class="hlt">fault</span> zones at a range of pressure-temperature conditions to understand fluid migration throughout a <span class="hlt">fault</span>'s history, and how fluid-rock interaction modifies permeability and rheological characteristics. Field localities in the Rwenzori Mountains, western Uganda and the Outer Hebrides, north-west Scotland, have been selected for field work and sample collection. Here Archaean-age TTG gneisses have been <span class="hlt">faulted</span> within the upper 15km of the crust and have experienced fluid ingress. The Rwenzori Mountains are an anomalously uplifted horst-block <span class="hlt">located</span> in a transfer zone in the western rift of the East African Rift System. The north-western ridge is characterised by a tectonically simple western flank, where the partially mineralised Bwamba <span class="hlt">Fault</span> has detached from the Congo craton. Mineralisation is associated with hydrothermal fluids heated by a thermal body beneath the Semliki rift, and has resulted in substantial iron oxide precipitation within porous cataclasites. Non-mineralised <span class="hlt">faults</span> further north contain foliated gouges and show evidence of leaking fluids. These <span class="hlt">faults</span> serve as an analogue for <span class="hlt">faults</span> associated with the Lake Albert oil and gas prospects. The Outer Hebrides <span class="hlt">Fault</span> Zone (OHFZ) was largely active during the Caledonian Orogeny (ca. 430-400 Ma) at a deeper crustal level than the Ugandan rift <span class="hlt">faults</span>. Initial dry conditions were followed by fluid ingress during deformation that controlled its rheological behaviour. The transition also altered the existing permeability. The OHFZ is a natural laboratory in which to study brittle <span class="hlt">fault</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T21A0537B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T21A0537B"><span>Earthquakes and aseismic creep associated with growing <span class="hlt">fault</span>-related folds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burke, C. C.; Johnson, K. M.</p> <p>2017-12-01</p> <p>Blind thrust <span class="hlt">faults</span> overlain by growing anticlinal folds pose a seismic risk to many urban centers in the world. A large body of research has focused on using fold and growth strata geometry to infer the rate of slip on the causative <span class="hlt">fault</span> and the distribution of off-<span class="hlt">fault</span> deformation. However, because we have had few recorded large earthquakes on blind <span class="hlt">faults</span> underlying folds, it remains unclear how much of the folding occurs during large earthquakes or during the interseismic period accommodated by aseismic creep. Numerous kinematic and mechanical models as well as field observations demonstrate that flexural slip between sedimentary layering is an important mechanism of <span class="hlt">fault</span>-related folding. In this study, we run boundary element models of flexural-slip <span class="hlt">fault</span>-related folding to examine the extent to which energy is released seismically or aseismically throughout the evolution of the fold and <span class="hlt">fault</span>. We assume a <span class="hlt">fault</span> imbedded in viscoelastic mechanical layering under frictional contact. We assign depth-dependent frictional properties and adopt a rate-state friction formulation to simulate slip over time. We find that in many cases, a large percentage (greater than 50%) of fold growth is accomplished by aseismic creep at bedding and <span class="hlt">fault</span> contacts. The largest earthquakes tend to occur on the <span class="hlt">fault</span>, but a significant portion of the seismicity is distributed across bedding contacts through the fold. We are currently working to quantify these results using a large number of simulations with various fold and <span class="hlt">fault</span> geometries. Result outputs include <span class="hlt">location</span>, duration, and magnitude of events. As more simulations are completed, these results from different fold and <span class="hlt">fault</span> geometries will provide insight into how much folding occurs from these slip events. Generalizations from these simulations can be compared with observations of active <span class="hlt">fault</span>-related folds and used in the future to inform seismic hazard studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP43C0709B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP43C0709B"><span>Evolution of triangular topographic facets along active normal <span class="hlt">faults</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balogun, A.; Dawers, N. H.; Gasparini, N. M.; Giachetta, E.</p> <p>2011-12-01</p> <p> measurements of the triangular facets to represent possible <span class="hlt">locations</span> of <span class="hlt">fault</span> segment linkage associated with normal <span class="hlt">fault</span> evolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S23B0796C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S23B0796C"><span>Seismicity rate surge on <span class="hlt">faults</span> after shut-in: poroelastic response to fluid injection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, K. W.; Yoon, H.; Martinez, M. J.</p> <p>2017-12-01</p> <p>Subsurface energy activities such as geological CO2 storage and wastewater injection require injecting large amounts of fluid into the subsurface, which will alter the states of pore pressure and stress in the storage formation. One of the main issues for injection-induced seismicity is the post shut-in increases in the seismicity rate, often observed in the fluid-injection operation sites. The rate surge can be driven by the following mechanisms: (1) pore-pressure propagation into distant <span class="hlt">faults</span> after shut-in and (2) poroelastic stressing caused by well operations, depending on <span class="hlt">fault</span> geometry, hydraulic and mechanical properties of the formation, and injection history. We simulate the aerial view of the target reservoir intersected by strike-slip <span class="hlt">faults</span>, in which injection-induced pressure buildup encounters the <span class="hlt">faults</span> directly. We examine the poroelastic response of the <span class="hlt">faults</span> to fluid injection and perform a series of sensitivity tests considering: (1) permeability of the <span class="hlt">fault</span> zone, (2) <span class="hlt">locations</span> and the number of <span class="hlt">faults</span> with respect to the injection point, and (3) well operations with varying the injection rate. Our analysis of the Coulomb stress change suggests that the sealing <span class="hlt">fault</span> confines pressure diffusion which stabilizes or weakens the nearby conductive <span class="hlt">fault</span> depending on the injection <span class="hlt">location</span>. We perform the sensitivity test by changing injection scenarios (time-dependent rates), while keeping the total amount of injected fluids. Sensitivity analysis shows that gradual reduction of the injection rate minimizes the Coulomb stress change and the least seismicity rates are predicted. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA-0003525.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70025911','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70025911"><span>A shallow <span class="hlt">fault</span>-zone structure illuminated by trapped waves in the Karadere-Duzce branch of the North Anatolian <span class="hlt">Fault</span>, western Turkey</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ben-Zion, Y.; Peng, Z.; Okaya, D.; Seeber, L.; Armbruster, J.G.; Ozer, N.; Michael, A.J.; Baris, S.; Aktar, M.</p> <p>2003-01-01</p> <p>We discuss the subsurface structure of the Karadere-Duzce branch of the North Anatolian <span class="hlt">Fault</span> based on analysis of a large seismic data set recorded by a local PASSCAL network in the 6 months following the Mw = 7.4 1999 Izmit earthquake. Seismograms observed at stations <span class="hlt">located</span> in the immediate vicinity of the rupture zone show motion amplification and long-period oscillations in both P- and S-wave trains that do not exist in nearby off-<span class="hlt">fault</span> stations. Examination of thousands of waveforms reveals that these characteristics are commonly generated by events that are well outside the <span class="hlt">fault</span> zone. The anomalous features in <span class="hlt">fault</span>-zone seismograms produced by events not necessarily in the <span class="hlt">fault</span> may be referred to generally as <span class="hlt">fault</span>-zone-related site effects. The oscillatory shear wave trains after the direct S arrival in these seismograms are analysed as trapped waves propagating in a low-velocity <span class="hlt">fault</span>-zone layer. The time difference between the S arrival and trapped waves group does not grow systematically with increasing source-receiver separation along the <span class="hlt">fault</span>. These observations imply that the trapping of seismic energy in the Karadere-Duzce rupture zone is generated by a shallow <span class="hlt">fault</span>-zone layer. Traveltime analysis and synthetic waveform modelling indicate that the depth of the trapping structure is approximately 3-4 km. The synthetic waveform modelling indicates further that the shallow trapping structure has effective waveguide properties consisting of thickness of the order of 100 m, a velocity decrease relative to the surrounding rock of approximately 50 per cent and an S-wave quality factor of 10-15. The results are supported by large 2-D and 3-D parameter space studies and are compatible with recent analyses of trapped waves in a number of other <span class="hlt">faults</span> and rupture zones. The inferred shallow trapping structure is likely to be a common structural element of <span class="hlt">fault</span> zones and may correspond to the top part of a flower-type structure. The motion amplification</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1616429M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1616429M"><span>3D <span class="hlt">Fault</span> Network of the Murchison Domain, Yilgarn Craton</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murdie, Ruth; Gessner, Klaus</p> <p>2014-05-01</p> <p>'s pmd*CRC Eastern Goldfields model. In the central portion, the major <span class="hlt">faults</span> such as the Youanmi and Wattle Creek, dip to the east and can be followed into the fabric of the Yarraquin Seismic Province. The Wattle Creek Shear Zone in particular can be traced on all three of the Youanmi seismic lines. The greenstones are cradled between these major <span class="hlt">faults</span> and antithetic westward dipping subsidiary <span class="hlt">faults</span> such as the Edale Shear Zone. While the Ida <span class="hlt">Fault</span> cannot be <span class="hlt">located</span> with great confidence, the slight drop in Moho depth toward the east and the overall change of seismic texture delineate the Youanmi-Eastern Goldfields boundary. The Lawler's Anticline, presumably <span class="hlt">located</span> in the hanging wall of the Ida <span class="hlt">Fault</span>, again changes the style of <span class="hlt">faulting</span> with the Lawler's tonalite forming the core of a 10 km-scale antiform. The <span class="hlt">fault</span> network presented here is a milestone to a craton-wide integrated structural model and will hopefully contribute to provide a better spatial context for geological, geochemical and geophysical data in our quest to understand the tectonics and mineral potential of the Yilgarn craton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.6786A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.6786A"><span><span class="hlt">Fault</span> fluid evolution at the outermost edges of the southern Apennines fold-and-thrust belt, Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agosta, Fabrizio; Belviso, Claudia; Cavalcante, Francesco; Vita Petrullo, Angela</p> <p>2017-04-01</p> <p> an <span class="hlt">accurate</span> analysis of their abutting and crosscutting relationships, we envision that the <span class="hlt">fault</span> fluid was first likely derived from a deep-seated, acid fluid, which interacted with either Triassic or Messinian in age evaporitic rocks during its ascendance from depth. From such a fluid, jarosite precipitated within N-S and NE-SW joints and sheared joints <span class="hlt">located</span> both away and within the <span class="hlt">fault</span> damage zone. Then, very warm fluids similar to the lahars that were channeled along the eastern flank of the Vulture Volcano caused the precipitation of Opal A within the dense fracture network of the footwall damage zone, likely causing its hydraulic fracturing, and in the N-S striking veins present in the vicinity of the <span class="hlt">fault</span> zone. Finally, gotheite coated the major slickensides and sealed the NE-SW fractures, postdating all previous mineralization. Gothetite precipitate from a <span class="hlt">fault</span> fluid, meteoric in origin, which interacted with the volcanic aquifer causing oxidation of the iron-rich minerals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27370486','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27370486"><span><span class="hlt">Fault</span> detection, isolation, and diagnosis of self-validating multifunctional sensors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Jing-Li; Chen, Yin-Sheng; Zhang, Li-Li; Sun, Zhen</p> <p>2016-06-01</p> <p>A novel <span class="hlt">fault</span> detection, isolation, and diagnosis (FDID) strategy for self-validating multifunctional sensors is presented in this paper. The sparse non-negative matrix factorization-based method can effectively detect <span class="hlt">faults</span> by using the squared prediction error (SPE) statistic, and the variables contribution plots based on SPE statistic can help to <span class="hlt">locate</span> and isolate the faulty sensitive units. The complete ensemble empirical mode decomposition is employed to decompose the <span class="hlt">fault</span> signals to a series of intrinsic mode functions (IMFs) and a residual. The sample entropy (SampEn)-weighted energy values of each IMFs and the residual are estimated to represent the characteristics of the <span class="hlt">fault</span> signals. Multi-class support vector machine is introduced to identify the <span class="hlt">fault</span> mode with the purpose of diagnosing status of the faulty sensitive units. The performance of the proposed strategy is compared with other <span class="hlt">fault</span> detection strategies such as principal component analysis, independent component analysis, and <span class="hlt">fault</span> diagnosis strategies such as empirical mode decomposition coupled with support vector machine. The proposed strategy is fully evaluated in a real self-validating multifunctional sensors experimental system, and the experimental results demonstrate that the proposed strategy provides an excellent solution to the FDID research topic of self-validating multifunctional sensors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MSSP...88..123A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MSSP...88..123A"><span>Fusion information entropy method of rolling bearing <span class="hlt">fault</span> diagnosis based on n-dimensional characteristic parameter distance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ai, Yan-Ting; Guan, Jiao-Yue; Fei, Cheng-Wei; Tian, Jing; Zhang, Feng-Ling</p> <p>2017-05-01</p> <p>To monitor rolling bearing operating status with casings in real time efficiently and <span class="hlt">accurately</span>, a fusion method based on n-dimensional characteristic parameters distance (n-DCPD) was proposed for rolling bearing <span class="hlt">fault</span> diagnosis with two types of signals including vibration signal and acoustic emission signals. The n-DCPD was investigated based on four information entropies (singular spectrum entropy in time domain, power spectrum entropy in frequency domain, wavelet space characteristic spectrum entropy and wavelet energy spectrum entropy in time-frequency domain) and the basic thought of fusion information entropy <span class="hlt">fault</span> diagnosis method with n-DCPD was given. Through rotor simulation test rig, the vibration and acoustic emission signals of six rolling bearing <span class="hlt">faults</span> (ball <span class="hlt">fault</span>, inner race <span class="hlt">fault</span>, outer race <span class="hlt">fault</span>, inner-ball <span class="hlt">faults</span>, inner-outer <span class="hlt">faults</span> and normal) are collected under different operation conditions with the emphasis on the rotation speed from 800 rpm to 2000 rpm. In the light of the proposed fusion information entropy method with n-DCPD, the diagnosis of rolling bearing <span class="hlt">faults</span> was completed. The <span class="hlt">fault</span> diagnosis results show that the fusion entropy method holds high precision in the recognition of rolling bearing <span class="hlt">faults</span>. The efforts of this study provide a novel and useful methodology for the <span class="hlt">fault</span> diagnosis of an aeroengine rolling bearing.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Tecto..36.2647R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Tecto..36.2647R"><span>Slip Inversion Along Inner Fore-Arc <span class="hlt">Faults</span>, Eastern Tohoku, Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Regalla, Christine; Fisher, Donald M.; Kirby, Eric; Oakley, David; Taylor, Stephanie</p> <p>2017-11-01</p> <p>The kinematics of deformation in the overriding plate of convergent margins may vary across timescales ranging from a single seismic cycle to many millions of years. In Northeast Japan, a network of active <span class="hlt">faults</span> has accommodated contraction across the arc since the Pliocene, but several <span class="hlt">faults</span> <span class="hlt">located</span> along the inner fore arc experienced extensional aftershocks following the 2011 Tohoku-oki earthquake, opposite that predicted from the geologic record. This observation suggests that fore-arc <span class="hlt">faults</span> may be favorable for stress triggering and slip inversion, but the geometry and deformation history of these <span class="hlt">fault</span> systems are poorly constrained. Here we document the Neogene kinematics and subsurface geometry of three prominent fore-arc <span class="hlt">faults</span> in Tohoku, Japan. Geologic mapping and dating of growth strata provide evidence for a 5.6-2.2 Ma initiation of Plio-Quaternary contraction along the Oritsume, Noheji, and Futaba <span class="hlt">Faults</span> and an earlier phase of Miocene extension from 25 to 15 Ma along the Oritsume and Futaba <span class="hlt">Faults</span> associated with the opening of the Sea of Japan. Kinematic modeling indicates that these <span class="hlt">faults</span> have listric geometries, with ramps that dip 40-65°W and sole into subhorizontal detachments at 6-10 km depth. These <span class="hlt">fault</span> systems can experience both normal and thrust sense slip if they are mechanically weak relative to the surrounding crust. We suggest that the inversion history of Northeast Japan primed the fore arc with a network of weak <span class="hlt">faults</span> mechanically and geometrically favorable for slip inversion over geologic timescales and in response to secular variations in stress state associated with the megathrust seismic cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999Icar..141...53T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999Icar..141...53T"><span>Astypalaea Linea: A Large-Scale Strike-Slip <span class="hlt">Fault</span> on Europa</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tufts, B. Randall; Greenberg, Richard; Hoppa, Gregory; Geissler, Paul</p> <p>1999-09-01</p> <p>Astypalaea Linea is an 810-km strike-slip <span class="hlt">fault</span>, <span class="hlt">located</span> near the south pole of Europa. In length, it rivals the San Andreas <span class="hlt">Fault</span> in California, and it is the largest strike-slip <span class="hlt">fault</span> yet known on Europa. The <span class="hlt">fault</span> was discovered using Voyager 2 images, based upon the presence of familiar strike-slip features including linearity, pull-aparts, and possible braids, and upon the offset of multiple piercing points. <span class="hlt">Fault</span> displacement is 42 km, right-lateral, in the southern and central parts and probably throughout. Pull-aparts present along the <span class="hlt">fault</span> trace probably are gaps in the lithosphere bounded by vertical cracks, and which opened due to <span class="hlt">fault</span> motion and filled with material from below. Crosscutting relationships suggest the <span class="hlt">fault</span> to be of intermediate relative age. The <span class="hlt">fault</span> may have initiated as a crack due to tension from combined diurnal tides and nonsynchronous rotation, according to the tectonic model of R. Greenberg et al. (1998a, Icarus135, 64-78). Under the influence of varying diurnal tides, strike-slip offset may have occurred through a process called “walking,” which depends upon an inelastic lithospheric response to displacement. Alternatively, <span class="hlt">fault</span> displacement may have been driven by currents in the theorized Europan ocean, which may have created simple shear structures such as braids. The discovery of Astypalaea Linea extends the geographical range of lateral motion on Europa. Such motion requires the presence of a decoupling zone of ductile ice or liquid water, a sufficiently rigid lithosphere, and a mechanism to consume surface area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/935424','SCIGOV-STC'); return false;" href="https://www.osti.gov/servlets/purl/935424"><span>Helicopter magnetic survey conducted to <span class="hlt">locate</span> wells</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Veloski, G.A.; Hammack, R.W.; Stamp, V.</p> <p>2008-07-01</p> <p>A helicopter magnetic survey was conducted in August 2007 over 15.6 sq mi at the Naval Petroleum Reserve No. 3’s (NPR-3) Teapot Dome Field near Casper, Wyoming. The survey’s purpose was to <span class="hlt">accurately</span> <span class="hlt">locate</span> wells drilled there during more than 90 years of continuous oilfield operation. The survey was conducted at low altitude and with closely spaced flight lines to improve the detection of wells with weak magnetic response and to increase the resolution of closely spaced wells. The survey was in preparation for a planned CO2 flood for EOR, which requires a complete well inventory with <span class="hlt">accurate</span> <span class="hlt">locations</span> formore » all existing wells. The magnetic survey was intended to <span class="hlt">locate</span> wells missing from the well database and to provide <span class="hlt">accurate</span> <span class="hlt">locations</span> for all wells. The ability of the helicopter magnetic survey to <span class="hlt">accurately</span> <span class="hlt">locate</span> wells was accomplished by comparing airborne well picks with well <span class="hlt">locations</span> from an intense ground search of a small test area.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SPIE10157E..1LS','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SPIE10157E..1LS"><span>Potential <span class="hlt">fault</span> region detection in TFDS images based on convolutional neural network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Junhua; Xiao, Zhongwen</p> <p>2016-10-01</p> <p>In recent years, more than 300 sets of Trouble of Running Freight Train Detection System (TFDS) have been installed on railway to monitor the safety of running freight trains in China. However, TFDS is simply responsible for capturing, transmitting, and storing images, and fails to recognize <span class="hlt">faults</span> automatically due to some difficulties such as such as the diversity and complexity of <span class="hlt">faults</span> and some low quality images. To improve the performance of automatic <span class="hlt">fault</span> recognition, it is of great importance to <span class="hlt">locate</span> the potential <span class="hlt">fault</span> areas. In this paper, we first introduce a convolutional neural network (CNN) model to TFDS and propose a potential <span class="hlt">fault</span> region detection system (PFRDS) for simultaneously detecting four typical types of potential <span class="hlt">fault</span> regions (PFRs). The experimental results show that this system has a higher performance of image detection to PFRs in TFDS. An average detection recall of 98.95% and precision of 100% are obtained, demonstrating the high detection ability and robustness against various poor imaging situations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890008675','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890008675"><span>Impact of device level <span class="hlt">faults</span> in a digital avionic processor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Suk, Ho Kim</p> <p>1989-01-01</p> <p>This study describes an experimental analysis of the impact of gate and device-level <span class="hlt">faults</span> in the processor of a Bendix BDX-930 flight control system. Via mixed mode simulation, <span class="hlt">faults</span> were injected at the gate (stuck-at) and at the transistor levels and, their propagation through the chip to the output pins was measured. The results show that there is little correspondence between a stuck-at and a device-level <span class="hlt">fault</span> model, as far as error activity or detection within a functional unit is concerned. In so far as error activity outside the injected unit and at the output pins are concerned, the stuck-at and device models track each other. The stuck-at model, however, overestimates, by over 100 percent, the probability of <span class="hlt">fault</span> propagation to the output pins. An evaluation of the Mean Error Durations and the Mean Time Between Errors at the output pins shows that the stuck-at model significantly underestimates (by 62 percent) the impact of an internal chip <span class="hlt">fault</span> on the output pins. Finally, the study also quantifies the impact of device <span class="hlt">fault</span> by <span class="hlt">location</span>, both internally and at the output pins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSG....73...97I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSG....73...97I"><span>What can the dihedral angle of conjugate-<span class="hlt">faults</span> tell us?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ismat, Zeshan</p> <p>2015-04-01</p> <p>Deformation within the upper crust (elastico-frictional regime) is largely accommodated by fractures and conjugate <span class="hlt">faults</span>. The Coulomb fracture criterion leads us to expect that the average dihedral angle of conjugate-<span class="hlt">fault</span> sets is expected to be ∼60°. Experiments, however, reveal a significant amount of scatter from this 60° average. The confining pressure under which these rocks are deformed is a contributing factor to this scatter. The Canyon Range syncline, Sevier fold-thrust belt (USA) and the Jebel Bani, Anti-Atlas fold-belt (Morocco) both folded under different depths, within the elastico-frictional regime, by cataclastic flow. Conjugate-<span class="hlt">fault</span> sets assisted deformation by cataclastic flow. The Canyon Range syncline and the Jebel Bani are used here as natural examples to test the relationship between the dihedral angle of conjugate-<span class="hlt">faults</span> and confining pressure. Variations is confining pressure are modeled by the difference in depth of deformation and position within the folds. Results from this study show that the dihedral angle increases with an increase in depth and within the hinge regions of folds, where space problems commonly occur. Moreover, the shortening directions based on the acute bisectors of conjugate-<span class="hlt">faults</span> may not be <span class="hlt">accurately</span> determined if the dihedral angles are unusually large or small, leading to incorrect kinematic analyses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V23B2827H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V23B2827H"><span>Spatial Patterns of Geomorphic Surface Features and <span class="hlt">Fault</span> Morphology Based on Diffusion Equation Modeling of the Kumroch <span class="hlt">Fault</span> Kamchatka Peninsula, Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heinlein, S. N.</p> <p>2013-12-01</p> <p>Remote sensing data sets are widely used for evaluation of surface manifestations of active tectonics. This study utilizes ASTER GDEM and Landsat ETM+ data sets with Google Earth images draped over terrain models. This study evaluates 1) the surrounding surface geomorphology of the study area with these data sets and 2) the morphology of the Kumroch <span class="hlt">Fault</span> using diffusion modeling to estimate constant diffusivity (κ) and estimate slip rates by means of real ground data measured across <span class="hlt">fault</span> scarps by Kozhurin et al. (2006). Models of the evolution of <span class="hlt">fault</span> scarp morphology provide time elapsed since slip initiated on a <span class="hlt">faults</span> surface and may therefore provide more <span class="hlt">accurate</span> estimates of slip rate than the rate calculated by dividing scarp offset by the age of the ruptured surface. Profile modeling of scarps collected by Kozhurin et al. (2006) formed by several events distributed through time and were evaluated using a constant slip rate (CSR) solution which yields a value A/κ (1/2 slip rate/diffusivity). Time elapsed since slip initiated on the <span class="hlt">fault</span> is determined by establishing a value for κ and measuring total scarp offset. CSR nonlinear modeling estimated of κ range from 8m2/ka - 14m2/ka on the Kumroch <span class="hlt">Fault</span> which indicates a slip rates of 0.6 mm/yr - 1.0 mm/yr since 3.4 ka -3.7 ka. This method provides a quick and inexpensive way to gather data for a regional tectonic study and establish estimated rates of tectonic activity. Analyses of the remote sensing data are providing new insight into the role of active tectonics within the region. Results from <span class="hlt">fault</span> scarp diffusion models of Mattson and Bruhn (2001) and DuRoss and Bruhn (2004) and Kozhurin et al. (2006), Kozhurin (2007), Kozhurin et al. (2008) and Pinegina et al. 2012 trench profiles of the KF as calibrated age <span class="hlt">fault</span> scarp diffusion rates were estimated. (-) mean that no data could be determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.S33A2801G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.S33A2801G"><span>Development of double-pair double difference <span class="hlt">location</span> algorithm and its application to the regular earthquakes and non-volcanic tremors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, H.; Zhang, H.</p> <p>2016-12-01</p> <p>Relocating high-precision earthquakes is a central task for monitoring earthquakes and studying the structure of earth's interior. The most popular <span class="hlt">location</span> method is the event-pair double-difference (DD) relative <span class="hlt">location</span> method, which uses the catalog and/or more <span class="hlt">accurate</span> waveform cross-correlation (WCC) differential times from event pairs with small inter-event separations to the common stations to reduce the effect of the velocity uncertainties outside the source region. Similarly, Zhang et al. [2010] developed a station-pair DD <span class="hlt">location</span> method which uses the differential times from common events to pairs of stations to reduce the effect of the velocity uncertainties near the source region, to relocate the non-volcanic tremors (NVT) beneath the San Andreas <span class="hlt">Fault</span> (SAF). To utilize advantages of both DD <span class="hlt">location</span> methods, we have proposed and developed a new double-pair DD <span class="hlt">location</span> method to use the differential times from pairs of events to pairs of stations. The new method can remove the event origin time and station correction terms from the inversion system and cancel out the effects of the velocity uncertainties near and outside the source region simultaneously. We tested and applied the new method on the northern California regular earthquakes to validate its performance. In comparison, among three DD <span class="hlt">location</span> methods, the new double-pair DD method can determine more <span class="hlt">accurate</span> relative <span class="hlt">locations</span> and the station-pair DD method can better improve the absolute <span class="hlt">locations</span>. Thus, we further proposed a new <span class="hlt">location</span> strategy combining station-pair and double-pair differential times to determine <span class="hlt">accurate</span> absolute and relative <span class="hlt">locations</span> at the same time. For NVTs, it is difficult to pick the first arrivals and derive the WCC event-pair differential times, thus the general practice is to measure station-pair envelope WCC differential times. However, station-pair tremor <span class="hlt">locations</span> are scattered due to the low-precision relative <span class="hlt">locations</span>. The ability that double-pair data</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050176477','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050176477"><span>Geometry of Thrust <span class="hlt">Faults</span> Beneath Amenthes Rupes, Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vidal, A.; Mueller, K. M.; Golombek, M. P.</p> <p>2005-01-01</p> <p>Amenthes Rupes is a 380 km-long lobate <span class="hlt">fault</span> scarp <span class="hlt">located</span> in the eastern hemisphere of Mars near the dichotomy boundary. The scarp is marked by about 1 km of vertical separation across a northeast dipping thrust <span class="hlt">fault</span> (top to the SW) and offsets heavily-cratered terrain of Late Noachian age, the visible portion of which was in place by 3.92 Ga and the buried portion in place between 4.08 and 4.27 Ga. The timing of scarp formation is difficult to closely constrain. Previous geologic mapping shows that near the northern end of Amenthes Rupes, Hesperian age basalts terminate at the scarp, suggesting that <span class="hlt">fault</span> slip predated the emplacement of these flows at 3.69 to 3.9 Ga. Maxwell and McGill also suggest the <span class="hlt">faulting</span> ceased before the final emplacement of the Late Hesperian lavas on Isidis Planitia. The trend of the <span class="hlt">faults</span> at Amenthes, like many thrust <span class="hlt">faults</span> at the dichotomy boundary, parallels the boundary itself. Schultz and Watters used a dislocation modeling program to match surface topography and vertical offset of the scarp at Amenthes Rupes, varying the dip and depth of <span class="hlt">faulting</span>, assuming a slip of 1.5 km on the <span class="hlt">fault</span>. They modeled <span class="hlt">faulting</span> below Amenthes Rupes as having a dip of between 25 and 30 degrees and a depth of 25 to 35 km, based on the best match to topography. Assuming a 25 degree dip and surface measurements of vertical offset of between 0.3 and 1.2 km, Watters later estimated the maximum displacement on the Amenthes Rupes <span class="hlt">fault</span> to be 2.90 km. However, these studies did not determine the geometry of the thrust using quantitative constraints that included shortening estimates. Amenthes Rupes deforms large preexisting impact craters. We use these craters to constrain shortening across the scarp and combine this with vertical separation to infer <span class="hlt">fault</span> geometry. <span class="hlt">Fault</span> dip was also estimated using measurements of scarp morphology. Measurements were based on 460 m (1/128 per pixel) digital elevation data from the Mars Orbiter Laser Altimeter (MOLA), an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSM.S43C..03V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSM.S43C..03V"><span>The Morelia-Acambay <span class="hlt">Fault</span> System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Velázquez Bucio, M.; Soria-Caballero, D.; Garduño-Monroy, V.; Mennella, L.</p> <p>2013-05-01</p> <p>The Trans-Mexican Volcanic Belt (TMVB) is one of the most actives and representative zones of Mexico geologically speaking. Research carried out in this area gives stratigraphic, seismologic and historical evidence of its recent activity during the quaternary (Martinez and Nieto, 1990). Specifically the Morelia-Acambay <span class="hlt">faults</span> system (MAFS) consist in a series of normal <span class="hlt">faults</span> of dominant direction E - W, ENE - WSW y NE - SW which is cut in center west of the Trans-Mexican Volcanic Belt. This <span class="hlt">fault</span> system appeared during the early Miocene although the north-south oriented structures are older and have been related to the activity of the tectonism inherited from the "Basin and Range" system, but that were reactivated by the east- west <span class="hlt">faults</span>. It is believed that the activity of these <span class="hlt">faults</span> has contributed to the creation and evolution of the longed lacustrine depressions such as: Chapala, Zacapu, Cuitzeo, Maravatio y Acambay also the <span class="hlt">location</span> of monogenetic volcanoes that conformed the Michoacan-Guanajuato volcanic field (MGVF) and tend to align in the direction of the SFMA dominant effort. In a historical time different segments of the MAFS have been the epicenter of earthquakes from moderated to strong magnitude like the events of 1858 in Patzcuaro, Acambay in 1912, 1979 in Maravatio and 2007 in Morelia, among others. Several detailed analysis and semi-detailed analysis through a GIS platform based in the vectorial archives and thematic charts 1:50 000 scaled from the data base of the INEGI which has allowed to remark the influence of the MAFS segments about the morphology of the landscape and the identification of other structures related to the movement of the existent <span class="hlt">faults</span> like fractures, alignments, collapses and others from the zone comprehended by the northwest of Morelia in Michoacán to the East of Acambay, Estado de México. Such analysis suggests that the <span class="hlt">fault</span> segments possess a normal displacement plus a left component. In addition it can be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPS...293..548Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPS...293..548Y"><span><span class="hlt">Fault</span> detection of the connection of lithium-ion power batteries based on entropy for electric vehicles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Lei; Wang, Zhenpo; Ma, Jun</p> <p>2015-10-01</p> <p>This paper proposes a method of <span class="hlt">fault</span> detection of the connection of Lithium-Ion batteries based on entropy for electric vehicle. In electric vehicle operation process, some factors, such as road conditions, driving habits, vehicle performance, always affect batteries by vibration, which easily cause loosing or virtual connection between batteries. Through the simulation of the battery charging and discharging experiment under vibration environment, the data of voltage fluctuation can be obtained. Meanwhile, an optimal filtering method is adopted using discrete cosine filter method to analyze the characteristics of system noise, based on the voltage set when batteries are working under different vibration frequency. Experimental data processed by filtering is analyzed based on local Shannon entropy, ensemble Shannon entropy and sample entropy. And the best way to find a method of <span class="hlt">fault</span> detection of the connection of lithium-ion batteries based on entropy is presented for electric vehicle. The experimental data shows that ensemble Shannon entropy can predict the <span class="hlt">accurate</span> time and the <span class="hlt">location</span> of battery connection failure in real time. Besides electric-vehicle industry, this method can also be used in other areas in complex vibration environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRB..118.1778H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRB..118.1778H"><span>Origins of oblique-slip <span class="hlt">faulting</span> during caldera subsidence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Holohan, Eoghan P.; Walter, Thomas R.; Schöpfer, Martin P. J.; Walsh, John J.; van Wyk de Vries, Benjamin; Troll, Valentin R.</p> <p>2013-04-01</p> <p>Although conventionally described as purely dip-slip, <span class="hlt">faults</span> at caldera volcanoes may have a strike-slip displacement component. Examples occur in the calderas of Olympus Mons (Mars), Miyakejima (Japan), and Dolomieu (La Reunion). To investigate this phenomenon, we use numerical and analog simulations of caldera subsidence caused by magma reservoir deflation. The numerical models constrain mechanical causes of oblique-slip <span class="hlt">faulting</span> from the three-dimensional stress field in the initial elastic phase of subsidence. The analog experiments directly characterize the development of oblique-slip <span class="hlt">faulting</span>, especially in the later, non-elastic phases of subsidence. The combined results of both approaches can account for the orientation, mode, and <span class="hlt">location</span> of oblique-slip <span class="hlt">faulting</span> at natural calderas. Kinematically, oblique-slip <span class="hlt">faulting</span> originates to resolve the following: (1) horizontal components of displacement that are directed radially toward the caldera center and (2) horizontal translation arising from off-centered or "asymmetric" subsidence. We informally call these two origins the "camera iris" and "sliding trapdoor" effects, respectively. Our findings emphasize the fundamentally three-dimensional nature of deformation during caldera subsidence. They hence provide an improved basis for analyzing structural, geodetic, and geophysical data from calderas, as well as analogous systems, such as mines and producing hydrocarbon reservoirs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.S11B..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.S11B..03S"><span>Paleoearthquakes on the Denali-Totschunda <span class="hlt">Fault</span> system: Preliminary Observations of Slip and Timing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schwartz, D. P.; Denali Fault Earthquake Geology Wp, .</p> <p>2003-12-01</p> <p>Understanding the behavior of large strike-slip <span class="hlt">fault</span> systems requires information about the amount of slip and timing of past earthquakes at different <span class="hlt">locations</span> along a <span class="hlt">fault</span>. A historical surface rupture adds a critically important baseline for calibration. During July 2003 we performed additional mapping of the 2002 Denali-Totschunda surface rupture with the goal of also measuring and dating slip during previous earthquakes. We were able to obtain slip values for prior events at a dozen <span class="hlt">locations</span> along Denali-Totschunda strike-slip rupture. We focused on the penultimate event, which is easiest to distinguish (slip from individual older events can eventually be measured). On the Denali <span class="hlt">fault</span> just west of the intersection with the Susitna Glacier thrust 2002 slip was low, 1.0 m to 1.5 m; cumulative slip from two events was 2.5-3.0, which is essentially double. On the 100-km-long section between Black Rapids Glacier and Gillett Pass, where 2002 slip averaged 5 m, three measurements indicate penultimate-event slip was about the same as 2002. The 7-8 m offset section east of Gillett Pass has the clearest paleoevent slip history. We measured three <span class="hlt">locations</span> where 2002 slip was 7-8m and cumulative offset on channels was 14.5-16 m. Along this section previous workers noted gullies with 15 m offsets before the 2002 earthquake, suggesting the past three events here had similar slip. On the Totschunda <span class="hlt">fault</span> paleo offsets appear to be similar in amount to 2002. At one locality we measured 2.8 m in 2002 and 5.4 m for two events. A second site had 1.0-1.4 m of offset in 2002 and 3.1 m for two events. A third <span class="hlt">location</span> yielded 3.3 m in 2002 and 10.8 m on a paleochannel, which could represent three events with similar slip. A <span class="hlt">location</span> in the Denali-Totschunda transition zone had a 5-6 m-high scarp and a well-developed sag pond, indicating that this complex part of the <span class="hlt">fault</span> system has been active in previous events. The major observation is that the paleo offset measurements</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T33E0776P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T33E0776P"><span>Interactions between Polygonal Normal <span class="hlt">Faults</span> and Larger Normal <span class="hlt">Faults</span>, Offshore Nova Scotia, Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pham, T. Q. H.; Withjack, M. O.; Hanafi, B. R.</p> <p>2017-12-01</p> <p>Polygonal <span class="hlt">faults</span>, small normal <span class="hlt">faults</span> with polygonal arrangements that form in fine-grained sedimentary rocks, can influence ground-water flow and hydrocarbon migration. Using well and 3D seismic-reflection data, we have examined the interactions between polygonal <span class="hlt">faults</span> and larger normal <span class="hlt">faults</span> on the passive margin of offshore Nova Scotia, Canada. The larger normal <span class="hlt">faults</span> strike approximately E-W to NE-SW. Growth strata indicate that the larger normal <span class="hlt">faults</span> were active in the Late Cretaceous (i.e., during the deposition of the Wyandot Formation) and during the Cenozoic. The polygonal <span class="hlt">faults</span> were also active during the Cenozoic because they affect the top of the Wyandot Formation, a fine-grained carbonate sedimentary rock, and the overlying Cenozoic strata. Thus, the larger normal <span class="hlt">faults</span> and the polygonal <span class="hlt">faults</span> were both active during the Cenozoic. The polygonal <span class="hlt">faults</span> far from the larger normal <span class="hlt">faults</span> have a wide range of orientations. Near the larger normal <span class="hlt">faults</span>, however, most polygonal <span class="hlt">faults</span> have preferred orientations, either striking parallel or perpendicular to the larger normal <span class="hlt">faults</span>. Some polygonal <span class="hlt">faults</span> nucleated at the tip of a larger normal <span class="hlt">fault</span>, propagated outward, and linked with a second larger normal <span class="hlt">fault</span>. The strike of these polygonal <span class="hlt">faults</span> changed as they propagated outward, ranging from parallel to the strike of the original larger normal <span class="hlt">fault</span> to orthogonal to the strike of the second larger normal <span class="hlt">fault</span>. These polygonal <span class="hlt">faults</span> hard-linked the larger normal <span class="hlt">faults</span> at and above the level of the Wyandot Formation but not below it. We argue that the larger normal <span class="hlt">faults</span> created stress-enhancement and stress-reorientation zones for the polygonal <span class="hlt">faults</span>. Numerous small, polygonal <span class="hlt">faults</span> formed in the stress-enhancement zones near the tips of larger normal <span class="hlt">faults</span>. Stress-reorientation zones surrounded the larger normal <span class="hlt">faults</span> far from their tips. Fewer polygonal <span class="hlt">faults</span> are present in these zones, and, more importantly, most polygonal <span class="hlt">faults</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910001638','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910001638"><span><span class="hlt">Fault</span> diagnosis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Abbott, Kathy</p> <p>1990-01-01</p> <p>The objective of the research in this area of <span class="hlt">fault</span> management is to develop and implement a decision aiding concept for diagnosing <span class="hlt">faults</span>, especially <span class="hlt">faults</span> which are difficult for pilots to identify, and to develop methods for presenting the diagnosis information to the flight crew in a timely and comprehensible manner. The requirements for the diagnosis concept were identified by interviewing pilots, analyzing actual incident and accident cases, and examining psychology literature on how humans perform diagnosis. The diagnosis decision aiding concept developed based on those requirements takes abnormal sensor readings as input, as identified by a <span class="hlt">fault</span> monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the <span class="hlt">fault</span> and all components affected by the <span class="hlt">fault</span>. This concept was implemented for diagnosis of aircraft propulsion and hydraulic subsystems in a computer program called Draphys (Diagnostic Reasoning About Physical Systems). Draphys is unique in two important ways. First, it uses models of both functional and physical relationships in the subsystems. Using both models enables the diagnostic reasoning to identify the <span class="hlt">fault</span> propagation as the <span class="hlt">faulted</span> system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the <span class="hlt">faulted</span> system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the <span class="hlt">fault</span>. The crew interface research is examining display issues associated with presenting diagnosis information to the flight crew. One study examined issues for presenting system status information. One lesson learned from that study was that pilots found <span class="hlt">fault</span> situations to be more complex if they involved multiple subsystems. Another was pilots could identify the <span class="hlt">faulted</span> systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23436210','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23436210"><span>Finding <span class="hlt">faults</span>: analogical comparison supports spatial concept learning in geoscience.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jee, Benjamin D; Uttal, David H; Gentner, Dedre; Manduca, Cathy; Shipley, Thomas F; Sageman, Bradley</p> <p>2013-05-01</p> <p>A central issue in education is how to support the spatial thinking involved in learning science, technology, engineering, and mathematics (STEM). We investigated whether and how the cognitive process of analogical comparison supports learning of a basic spatial concept in geoscience, <span class="hlt">fault</span>. Because of the high variability in the appearance of <span class="hlt">faults</span>, it may be difficult for students to learn the category-relevant spatial structure. There is abundant evidence that comparing analogous examples can help students gain insight into important category-defining features (Gentner in Cogn Sci 34(5):752-775, 2010). Further, comparing high-similarity pairs can be especially effective at revealing key differences (Sagi et al. 2012). Across three experiments, we tested whether comparison of visually similar contrasting examples would help students learn the <span class="hlt">fault</span> concept. Our main findings were that participants performed better at identifying <span class="hlt">faults</span> when they (1) compared contrasting (<span class="hlt">fault</span>/no <span class="hlt">fault</span>) cases versus viewing each case separately (Experiment 1), (2) compared similar as opposed to dissimilar contrasting cases early in learning (Experiment 2), and (3) viewed a contrasting pair of schematic block diagrams as opposed to a single block diagram of a <span class="hlt">fault</span> as part of an instructional text (Experiment 3). These results suggest that comparison of visually similar contrasting cases helped distinguish category-relevant from category-irrelevant features for participants. When such comparisons occurred early in learning, participants were more likely to form an <span class="hlt">accurate</span> conceptual representation. Thus, analogical comparison of images may provide one powerful way to enhance spatial learning in geoscience and other STEM disciplines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MeScT..27l5006C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MeScT..27l5006C"><span>Multiple resolution chirp reflectometry for <span class="hlt">fault</span> localization and diagnosis in a high voltage cable in automotive electronics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Seung Jin; Lee, Chun Ku; Shin, Yong-June; Park, Jin Bae</p> <p>2016-12-01</p> <p>A multiple chirp reflectometry system with a <span class="hlt">fault</span> estimation process is proposed to obtain multiple resolution and to measure the degree of <span class="hlt">fault</span> in a target cable. A multiple resolution algorithm has the ability to localize <span class="hlt">faults</span>, regardless of <span class="hlt">fault</span> <span class="hlt">location</span>. The time delay information, which is derived from the normalized cross-correlation between the incident signal and bandpass filtered reflected signals, is converted to a <span class="hlt">fault</span> <span class="hlt">location</span> and cable length. The in-phase and quadrature components are obtained by lowpass filtering of the mixed signal of the incident signal and the reflected signal. Based on in-phase and quadrature components, the reflection coefficient is estimated by the proposed <span class="hlt">fault</span> estimation process including the mixing and filtering procedure. Also, the measurement uncertainty for this experiment is analyzed according to the Guide to the Expression of Uncertainty in Measurement. To verify the performance of the proposed method, we conduct comparative experiments to detect and measure <span class="hlt">faults</span> under different conditions. Considering the installation environment of the high voltage cable used in an actual vehicle, target cable length and <span class="hlt">fault</span> position are designed. To simulate the degree of <span class="hlt">fault</span>, the variety of termination impedance (10 Ω , 30 Ω , 50 Ω , and 1 \\text{k} Ω ) are used and estimated by the proposed method in this experiment. The proposed method demonstrates advantages in that it has multiple resolution to overcome the blind spot problem, and can assess the state of the <span class="hlt">fault</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/6211604','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/biblio/6211604"><span>Arc <span class="hlt">fault</span> detection system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Jha, K.N.</p> <p>1999-05-18</p> <p>An arc <span class="hlt">fault</span> detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings <span class="hlt">located</span> in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker <span class="hlt">located</span> between the switchboard and a power supply to remove the supply of power to the switchboard. 1 fig.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/servlets/purl/872294','DOE-PATENT-XML'); return false;" href="https://www.osti.gov/servlets/purl/872294"><span>Arc <span class="hlt">fault</span> detection system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Jha, Kamal N.</p> <p>1999-01-01</p> <p>An arc <span class="hlt">fault</span> detection system for use on ungrounded or high-resistance-grounded power distribution systems is provided which can be retrofitted outside electrical switchboard circuits having limited space constraints. The system includes a differential current relay that senses a current differential between current flowing from secondary windings <span class="hlt">located</span> in a current transformer coupled to a power supply side of a switchboard, and a total current induced in secondary windings coupled to a load side of the switchboard. When such a current differential is experienced, a current travels through a operating coil of the differential current relay, which in turn opens an upstream circuit breaker <span class="hlt">located</span> between the switchboard and a power supply to remove the supply of power to the switchboard.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.S44C..03E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.S44C..03E"><span>Magnetotelluric Studies of <span class="hlt">Fault</span> Zones Surrounding the 2016 Pawnee, Oklahoma Earthquake</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Evans, R. L.; Key, K.; Atekwana, E. A.</p> <p>2016-12-01</p> <p>Since 2008, there has been a dramatic increase in earthquake activity in the central United States in association with major oil and gas operations. Oklahoma is now considered one the most seismically active states. Although seismic networks are able to detect activity and map its locus, they are unable to image the distribution of fluids in the <span class="hlt">fault</span> responsible for triggering seismicity. Electrical geophysical methods are ideally suited to image fluid bearing <span class="hlt">faults</span> since the injected waste-waters are highly saline and hence have a high electrical conductivity. To date, no study has imaged the fluids in the <span class="hlt">faults</span> in Oklahoma and made a direct link to the seismicity. The 2016 M5.8 Pawnee, Oklahoma earthquake provides an unprecedented opportunity for scientists to provide that link. Several injection wells are <span class="hlt">located</span> within a 20 km radius of the epicenter; and studies have suggested that injection of fluids in high-volume wells can trigger earthquakes as far away as 30 km. During late October to early November, 2016, we are collecting magnetotelluric (MT) data with the aim of constraining the distribution of fluids in the <span class="hlt">fault</span> zone. The MT technique uses naturally occurring electric and magnetic fields measured at Earth's surface to measure conductivity structure. We plan to carry out a series of short two-dimensional (2D) profiles of wideband MT acquisition <span class="hlt">located</span> through areas where the <span class="hlt">fault</span> recently ruptured and seismic activity is concentrated and also across the <span class="hlt">faults</span> in the vicinity that did not rupture. The integration of our results and ongoing seismic studies will lead to a better understanding of the links between fluid injection and seismicity.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.9822G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.9822G"><span>The role of large strike-slip <span class="hlt">faults</span> in a convergent continental setting - first results from the Dzhungarian <span class="hlt">Fault</span> in Eastern Kazakhstan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grützner, Christoph; Campbell, Grace; Elliott, Austin; Walker, Richard; Abdrakhmatov, Kanatbek</p> <p>2016-04-01</p> <p>The Tien Shan and the Dzhungarian Ala-tau mountain ranges in Eastern Kazakhstan and China take up a significant portion of the total convergence between India and Eurasia, despite the fact that they are more than 1000 km away from the actual plate boundary. Shortening is accommodated by large thrust <span class="hlt">faults</span> that strike more or less perpendicular to the convergence vector, and by a set of conjugate strike-slip <span class="hlt">faults</span>. Some of these strike-slip <span class="hlt">faults</span> are major features of several hundred kilometres length and have produced great historical earthquakes. In most cases, little is known about their slip-rates and earthquake history, and thus, about their role in the regional tectonic setting. This study deals with the NW-SE trending Dzhungarian <span class="hlt">Fault</span>, a more than 350 km-long, right-lateral strike slip feature. It borders the Dzhungarian Ala-tau range and forms one edge of the so-called Dzhungarian Gate. The <span class="hlt">fault</span> curves from a ~305° strike at its NW tip in Kazakhstan to a ~328° strike in China. No historical ruptures are known from the Kazakh part of the <span class="hlt">fault</span>. A possible rupture in 1944 in the Chinese part remains discussed. We used remote sensing, Structure-from-Motion (SfM), differential GPS, field mapping, and Quaternary dating of offset geological markers in order to map the <span class="hlt">fault</span>-related morphology and to measure the slip rate of the <span class="hlt">fault</span> at several <span class="hlt">locations</span> along strike. We also aimed to find out the age of the last surface rupturing earthquake and to determine earthquake recurrence intervals and magnitudes. We were further interested in the relation between horizontal and vertical motion along the <span class="hlt">fault</span> and possible <span class="hlt">fault</span> segmentation. Here we present first results from our 2015 survey. High-resolution digital elevation models of offset river terraces allowed us to determine the slip vector of the most recent earthquake. Preliminary dating results from abandoned fluvial terraces allow us to speculate on a late Holocene surface rupturing event. Morphological</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T41B2919W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T41B2919W"><span>Preliminary Investigation and Surficial Mapping of the <span class="hlt">Faults</span> North and South of Blacktail Butte, Teton County, Wyoming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wittke, S.</p> <p>2016-12-01</p> <p>The Wyoming State Geological Survey has focused on surficial mapping and examination of the <span class="hlt">location</span> and offset of <span class="hlt">faults</span> north and south of Blacktail Butte in eastern Jackson Hole, Wyoming. The <span class="hlt">fault</span> strands south of Blacktail Butte are classified as Late Quaternary, the <span class="hlt">faults</span> north of the butte are considered Class B structures by the USGS. Little to no detailed studies, including paleoseismic investigations or <span class="hlt">fault</span> scarp morphology, have been conducted on these <span class="hlt">fault</span> strands. The acquisition of LiDAR for the Grand Teton National Park and recent aerial photographs provided data necessary for revised mapping and geomorphic interpretation of <span class="hlt">fault</span>-related features north and south of Blacktail Butte. New <span class="hlt">fault</span> traces and geomorphic features were identified in the LiDAR data which had not been previously mapped. Mapped <span class="hlt">fault</span> traces are intermittent, forming a 1.5 km-long graben that extends south from Blacktail Butte and crosses a loess-mantle late-Pleistocene terrace generated from the Pinedale glaciation. Other lineaments were identified that continued for another 0.5 km to the south. With very little vertical offset across the system and comparatively short <span class="hlt">fault</span> strands, the <span class="hlt">faults</span> may represent secondary features related to movement on another unidentified <span class="hlt">fault</span> within the basin. The secondary <span class="hlt">faults</span> north of Blacktail Butte were mapped based on geomorphic features and through LiDAR-based spatial analysis. The <span class="hlt">fault</span> scarps are relatively short and are present on alluvial fan and/or terrace deposits related to the Pinedale glaciation or on undated Holocene deposits. The scarps have little net vertical offset, suggesting they could also be secondary features related to movement from another unidentified <span class="hlt">fault</span> within the basin. Improved understanding of these <span class="hlt">fault</span> strands is significant because of the vicinity to populated areas within Jackson Hole and the possible relevance to the Teton <span class="hlt">Fault</span> system. To our knowledge, these <span class="hlt">fault</span> strands have not been proposed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70029072','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70029072"><span>Kinematics, mechanics, and potential earthquake hazards for <span class="hlt">faults</span> in Pottawatomie County, Kansas, USA</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ohlmacher, G.C.; Berendsen, P.</p> <p>2005-01-01</p> <p>Many stable continental regions have subregions with poorly defined earthquake hazards. Analysis of minor structures (folds and <span class="hlt">faults</span>) in these subregions can improve our understanding of the tectonics and earthquake hazards. Detailed structural mapping in Pottawatomie County has revealed a suite consisting of two uplifted blocks aligned along a northeast trend and surrounded by <span class="hlt">faults</span>. The first uplift is <span class="hlt">located</span> southwest of the second. The northwest and southeast sides of these uplifts are bounded by northeast-trending right-lateral <span class="hlt">faults</span>. To the east, both uplifts are bounded by north-trending reverse <span class="hlt">faults</span>, and the first uplift is bounded by a north-trending high-angle <span class="hlt">fault</span> to the west. The structural suite occurs above a basement <span class="hlt">fault</span> that is part of a series of north-northeast-trending <span class="hlt">faults</span> that delineate the Humboldt <span class="hlt">Fault</span> Zone of eastern Kansas, an integral part of the Midcontinent Rift System. The favored kinematic model is a contractional stepover (push-up) between echelon strike-slip <span class="hlt">faults</span>. Mechanical modeling using the boundary element method supports the interpretation of the uplifts as contractional stepovers and indicates that an approximately east-northeast maximum compressive stress trajectory is responsible for the formation of the structural suite. This stress trajectory suggests potential activity during the Laramide Orogeny, which agrees with the age of kimberlite emplacement in adjacent Riley County. The current stress field in Kansas has a N85??W maximum compressive stress trajectory that could potentially produce earthquakes along the basement <span class="hlt">faults</span>. Several epicenters of seismic events (<M2.0) are <span class="hlt">located</span> within 10 km of the structural suite. One epicenter is coincident with the northwest boundary of the uplift. This structural suite, a contractional stepover between echelon northeast-trending right-lateral <span class="hlt">faults</span>, is similar to that mapped in the New Madrid Seismic Zone, and both areas currently feature roughly east-west maximum</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JSeis..21.1641J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JSeis..21.1641J"><span>Intraplate seismicity along the Gedi <span class="hlt">Fault</span> in Kachchh rift basin of western India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Joshi, Vishwa; Rastogi, B. K.; Kumar, Santosh</p> <p>2017-11-01</p> <p>The Kachchh rift basin is <span class="hlt">located</span> on the western continental margin of India and has a history of experiencing large to moderate intraplate earthquakes with M ≥ 5. During the past two centuries, two large earthquakes of Mw 7.8 (1819) and Mw 7.7 (2001) have occurred in the Kachchh region, the latter with an epicenter near Bhuj. The aftershock activity of the 2001 Bhuj earthquake is still ongoing with migration of seismicity. Initially, epicenters migrated towards the east and northeast within the Kachchh region but, since 2007, it has also migrated to the south. The triggered <span class="hlt">faults</span> are mostly within 100 km and some up to 200 km distance from the epicentral area of the mainshock. Most of these <span class="hlt">faults</span> are trending in E-W direction, and some are transverse. It was noticed that some <span class="hlt">faults</span> generate earthquakes down to the Moho depth whereas some <span class="hlt">faults</span> show earthquake activity within the upper crustal volume. The Gedi <span class="hlt">Fault</span>, situated about 50 km northeast of the 2001 mainshock epicenter, triggered the largest earthquake of Mw 5.6 in 2006. We have carried out detailed seismological studies to evaluate the seismic potential of the Gedi <span class="hlt">Fault</span>. We have relocated 331 earthquakes by HypoDD to improve upon <span class="hlt">location</span> errors. Further, the relocated events are used to estimate the b value, p value, and fractal correlation dimension Dc of the <span class="hlt">fault</span> zone. The present study indicates that all the events along the Gedi <span class="hlt">Fault</span> are shallow in nature, with focal depths less than 20 km. The estimated b value shows that the Gedi aftershock sequence could be classified as Mogi's type 2 sequence, and the p value suggests a relatively slow decay of aftershocks. The <span class="hlt">fault</span> plane solutions of some selected events of Mw > 3.5 are examined, and activeness of the Gedi <span class="hlt">Fault</span> is assessed from the results of active <span class="hlt">fault</span> studies as well as GPS and InSAR results. All these results are critically examined to evaluate the material properties and seismic potential of the Gedi <span class="hlt">Fault</span> that may be useful</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S53B0707Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S53B0707Q"><span>Deciphering Stress State of Seismogenic <span class="hlt">Faults</span> in Oklahoma and Kansas Based on High-resolution Stress Maps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Y.; Chen, X.; Haffener, J.; Trugman, D. T.; Carpenter, B.; Reches, Z.</p> <p>2017-12-01</p> <p>Induced seismicity in Oklahoma and Kansas delineates clear <span class="hlt">fault</span> trends. It is assumed that fluid injection reactivates <span class="hlt">faults</span> which are optimally oriented relative to the regional tectonic stress field. We utilized recently improved earthquake <span class="hlt">locations</span> and more complete focal mechanism catalogs to quantitatively analyze the stress state of seismogenic <span class="hlt">faults</span> with high-resolution stress maps. The steps of analysis are: (1) Mapping the <span class="hlt">faults</span> by clustering seismicity using a nearest-neighbor approach, manually picking the <span class="hlt">fault</span> in each cluster and calculating the <span class="hlt">fault</span> geometry using principal component analysis. (2) Running a stress inversion with 0.2° grid spacing to produce an in-situ stress map. (3) The <span class="hlt">fault</span> stress state is determined from <span class="hlt">fault</span> geometry and a 3D Mohr circle. The parameter `understress' is calculated to quantify the criticalness of these <span class="hlt">faults</span>. If it approaches 0, the <span class="hlt">fault</span> is critically stressed; while understress=1 means there is no shear stress on the <span class="hlt">fault</span>. Our results indicate that most of the active <span class="hlt">faults</span> have a planar shape (planarity>0.8), and dip steeply (dip>70°). The <span class="hlt">fault</span> trends are distributed mainly in conjugate set ranges of [50°,70°] and [100°,120°]. More importantly, these conjugate trends are consistent with mapped basement fractures in southern Oklahoma, suggesting similar basement features from regional tectonics. The <span class="hlt">fault</span> length data shows a loglinear relationship with the maximum earthquake magnitude with an expected maximum magnitude range from 3.2 to 4.4 for most seismogenic <span class="hlt">faults</span>. Based on 3D local Mohr circle, we find that 61% of the <span class="hlt">faults</span> have low understress (<0.2); while several <span class="hlt">faults</span> with high understress (>0.5) are <span class="hlt">located</span> within highest-rate injection zones and therefore are likely to be influenced by high pore pressure. The <span class="hlt">faults</span> that hosted the largest earthquakes, M5.7 Prague and M5.8 Pawnee are critically stressed (understress < 0.08), whereas the <span class="hlt">fault</span> of M5 Fairview earthquake is only</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5982639','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5982639"><span>A Novel <span class="hlt">Fault</span> Diagnosis Method for Rotating Machinery Based on a Convolutional Neural Network</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yang, Tao; Gao, Wei</p> <p>2018-01-01</p> <p><span class="hlt">Fault</span> diagnosis is critical to ensure the safety and reliable operation of rotating machinery. Most methods used in <span class="hlt">fault</span> diagnosis of rotating machinery extract a few feature values from vibration signals for <span class="hlt">fault</span> diagnosis, which is a dimensionality reduction from the original signal and may omit some important <span class="hlt">fault</span> messages in the original signal. Thus, a novel diagnosis method is proposed involving the use of a convolutional neural network (CNN) to directly classify the continuous wavelet transform scalogram (CWTS), which is a time-frequency domain transform of the original signal and can contain most of the information of the vibration signals. In this method, CWTS is formed by discomposing vibration signals of rotating machinery in different scales using wavelet transform. Then the CNN is trained to diagnose <span class="hlt">faults</span>, with CWTS as the input. A series of experiments is conducted on the rotor experiment platform using this method. The results indicate that the proposed method can diagnose the <span class="hlt">faults</span> <span class="hlt">accurately</span>. To verify the universality of this method, the trained CNN was also used to perform <span class="hlt">fault</span> diagnosis for another piece of rotor equipment, and a good result was achieved. PMID:29734704</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/29734704','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/29734704"><span>A Novel <span class="hlt">Fault</span> Diagnosis Method for Rotating Machinery Based on a Convolutional Neural Network.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guo, Sheng; Yang, Tao; Gao, Wei; Zhang, Chen</p> <p>2018-05-04</p> <p><span class="hlt">Fault</span> diagnosis is critical to ensure the safety and reliable operation of rotating machinery. Most methods used in <span class="hlt">fault</span> diagnosis of rotating machinery extract a few feature values from vibration signals for <span class="hlt">fault</span> diagnosis, which is a dimensionality reduction from the original signal and may omit some important <span class="hlt">fault</span> messages in the original signal. Thus, a novel diagnosis method is proposed involving the use of a convolutional neural network (CNN) to directly classify the continuous wavelet transform scalogram (CWTS), which is a time-frequency domain transform of the original signal and can contain most of the information of the vibration signals. In this method, CWTS is formed by discomposing vibration signals of rotating machinery in different scales using wavelet transform. Then the CNN is trained to diagnose <span class="hlt">faults</span>, with CWTS as the input. A series of experiments is conducted on the rotor experiment platform using this method. The results indicate that the proposed method can diagnose the <span class="hlt">faults</span> <span class="hlt">accurately</span>. To verify the universality of this method, the trained CNN was also used to perform <span class="hlt">fault</span> diagnosis for another piece of rotor equipment, and a good result was achieved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMIN33A1297D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMIN33A1297D"><span>Spatiotemporal analysis of Quaternary normal <span class="hlt">faults</span> in the Northern Rocky Mountains, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davarpanah, A.; Babaie, H. A.; Reed, P.</p> <p>2010-12-01</p> <p>, are <span class="hlt">located</span>. The GIS based autocorrelation method, applied to the trace orientation, length, frequency, and spatial distribution for each age-defined <span class="hlt">fault</span> set, revealed spatial homogeneity for each specific set. The results of the method of Moran`sI and Geary`s C show no spatial autocorrelation among the trend of the <span class="hlt">fault</span> traces and their <span class="hlt">location</span>. Our results suggest that while lineaments of similar age define a clustered pattern in each domain, the overall distribution pattern of lineaments with different ages seems to be non-uniform (random). The directional distribution analysis reveals a distinct range of variation for <span class="hlt">fault</span> traces of different ages (i.e., some displaying ellipsis behavior). Among the Quaternary normal <span class="hlt">fault</span> sets, the youngest lineament set (i.e., last 150 years) defines the greatest ellipticity (eccentricity) and the least lineaments distribution variation. The frequency rose diagram for the entire Quaternary normal <span class="hlt">faults</span>, shows four major modes (around 360o, 330o, 300o, and 270o), and two minor modes (around 235 and 205).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27649171','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27649171"><span>Weak <span class="hlt">Fault</span> Feature Extraction of Rolling Bearings Based on an Improved Kurtogram.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Xianglong; Feng, Fuzhou; Zhang, Bingzhi</p> <p>2016-09-13</p> <p>Kurtograms have been verified to be an efficient tool in bearing <span class="hlt">fault</span> detection and diagnosis because of their superiority in extracting transient features. However, the short-time Fourier Transform is insufficient in time-frequency analysis and kurtosis is deficient in detecting cyclic transients. Those factors weaken the performance of the original kurtogram in extracting weak <span class="hlt">fault</span> features. Correlated Kurtosis (CK) is then designed, as a more effective solution, in detecting cyclic transients. Redundant Second Generation Wavelet Packet Transform (RSGWPT) is deemed to be effective in capturing more detailed local time-frequency description of the signal, and restricting the frequency aliasing components of the analysis results. The authors in this manuscript, combining the CK with the RSGWPT, propose an improved kurtogram to extract weak <span class="hlt">fault</span> features from bearing vibration signals. The analysis of simulation signals and real application cases demonstrate that the proposed method is relatively more <span class="hlt">accurate</span> and effective in extracting weak <span class="hlt">fault</span> features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5038758','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5038758"><span>Weak <span class="hlt">Fault</span> Feature Extraction of Rolling Bearings Based on an Improved Kurtogram</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chen, Xianglong; Feng, Fuzhou; Zhang, Bingzhi</p> <p>2016-01-01</p> <p>Kurtograms have been verified to be an efficient tool in bearing <span class="hlt">fault</span> detection and diagnosis because of their superiority in extracting transient features. However, the short-time Fourier Transform is insufficient in time-frequency analysis and kurtosis is deficient in detecting cyclic transients. Those factors weaken the performance of the original kurtogram in extracting weak <span class="hlt">fault</span> features. Correlated Kurtosis (CK) is then designed, as a more effective solution, in detecting cyclic transients. Redundant Second Generation Wavelet Packet Transform (RSGWPT) is deemed to be effective in capturing more detailed local time-frequency description of the signal, and restricting the frequency aliasing components of the analysis results. The authors in this manuscript, combining the CK with the RSGWPT, propose an improved kurtogram to extract weak <span class="hlt">fault</span> features from bearing vibration signals. The analysis of simulation signals and real application cases demonstrate that the proposed method is relatively more <span class="hlt">accurate</span> and effective in extracting weak <span class="hlt">fault</span> features. PMID:27649171</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMNS51B1825D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMNS51B1825D"><span>Near-Surface Geophysical Character of a Holocene <span class="hlt">Fault</span> Carrying Geothermal Flow Near Pyramid Lake, Nevada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dudley, C.; Dorsey, A.; Louie, J. N.; Schwering, P. C.; Pullammanappallil, S.</p> <p>2012-12-01</p> <p>Lines of calcium carbonate tufa columns mark recent <span class="hlt">faults</span> that cut 11 ka Lake Lahontan sediments at Astor Pass, north of Pyramid Lake, Nevada. Throughout the Great Basin, <span class="hlt">faults</span> appear to control the <span class="hlt">location</span> of geothermal resources, providing pathways for fluid migration. Reservoir-depth (greater than 1 km) seismic imaging at Astor Pass shows a <span class="hlt">fault</span> that projects to one of the lines of tufa columns at the surface. The presence of the tufa deposits suggests this <span class="hlt">fault</span> carried warm geothermal waters through the lakebed clay sediments in recent time. The warm fluids deposited the tufa when they hit cold Lake Lahontan water at the lakebed. Lake Lahontan covered this <span class="hlt">location</span> to a depth of at least 60 m at 11 ka. In collaboration with the Pyramid Lake Paiute Tribe, an Applied Geophysics class at UNR investigated the near-surface geophysical characteristics of this <span class="hlt">fault</span>. The survey comprises near-surface seismic reflection and refraction, nine near-surface refraction microtremor (SeisOpt® ReMi™) arrays, nine near-surface direct-current resistivity soundings, magnetic surveys, and gravity surveys at and near the tufa columns. The refraction microtremor results show shear velocities near tufa and <span class="hlt">faults</span> to be marginally lower, compared to Vs away from the <span class="hlt">faults</span>. Overall, the 30-m depth-averaged shear velocities are low, less than 300 m/s, consistent with the lakebed clay deposits. These results show no indication of any fast (> 500 m/s) tufa below the surface at or near the tufa columns. Vs30 averages were 274 ± 13 m/s on the <span class="hlt">fault</span>, 287 ± 2 m/s at 150 m east of the <span class="hlt">fault</span>, and 290 ± 15 m/s at 150 m west of the <span class="hlt">fault</span>. The P-velocity refraction optimization results also show no indication of high-velocity tufa buried below the surface in the Lahontan sediments, reinforcing the idea that all tufa was deposited above the lakebed surface. The seismic results provide a negative test of the hypothesis that deposition of the lakebeds in the Quaternary buried and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70042444','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70042444"><span>Low strength of deep San Andreas <span class="hlt">fault</span> gouge from SAFOD core</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lockner, David A.; Morrow, Carolyn A.; Moore, Diane E.; Hickman, Stephen H.</p> <p>2011-01-01</p> <p>The San Andreas <span class="hlt">fault</span> accommodates 28–34 mm yr−1 of right lateral motion of the Pacific crustal plate northwestward past the North American plate. In California, the <span class="hlt">fault</span> is composed of two distinct locked segments that have produced great earthquakes in historical times, separated by a 150-km-long creeping zone. The San Andreas <span class="hlt">Fault</span> Observatory at Depth (SAFOD) is a scientific borehole <span class="hlt">located</span> northwest of Parkfield, California, near the southern end of the creeping zone. Core was recovered from across the actively deforming San Andreas <span class="hlt">fault</span> at a vertical depth of 2.7 km (ref. 1). Here we report laboratory strength measurements of these <span class="hlt">fault</span> core materials at in situ conditions, demonstrating that at this locality and this depth the San Andreas <span class="hlt">fault</span> is profoundly weak (coefficient of friction, 0.15) owing to the presence of the smectite clay mineral saponite, which is one of the weakest phyllosilicates known. This Mg-rich clay is the low-temperature product of metasomatic reactions between the quartzofeldspathic wall rocks and serpentinite blocks in the <span class="hlt">fault</span>2, 3. These findings provide strong evidence that deformation of the mechanically unusual creeping portions of the San Andreas <span class="hlt">fault</span> system is controlled by the presence of weak minerals rather than by high fluid pressure or other proposed mechanisms1. The combination of these measurements of <span class="hlt">fault</span> core strength with borehole observations1, 4, 5 yields a self-consistent picture of the stress state of the San Andreas <span class="hlt">fault</span> at the SAFOD site, in which the <span class="hlt">fault</span> is intrinsically weak in an otherwise strong crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70034792','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70034792"><span>Low strength of deep San Andreas <span class="hlt">fault</span> gouge from SAFOD core</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lockner, D.A.; Morrow, C.; Moore, D.; Hickman, S.</p> <p>2011-01-01</p> <p>The San Andreas <span class="hlt">fault</span> accommodates 28-"34-???mm-???yr ????'1 of right lateral motion of the Pacific crustal plate northwestward past the North American plate. In California, the <span class="hlt">fault</span> is composed of two distinct locked segments that have produced great earthquakes in historical times, separated by a 150-km-long creeping zone. The San Andreas <span class="hlt">Fault</span> Observatory at Depth (SAFOD) is a scientific borehole <span class="hlt">located</span> northwest of Parkfield, California, near the southern end of the creeping zone. Core was recovered from across the actively deforming San Andreas <span class="hlt">fault</span> at a vertical depth of 2.7-???km (ref. 1). Here we report laboratory strength measurements of these <span class="hlt">fault</span> core materials at in situ conditions, demonstrating that at this locality and this depth the San Andreas <span class="hlt">fault</span> is profoundly weak (coefficient of friction, 0.15) owing to the presence of the smectite clay mineral saponite, which is one of the weakest phyllosilicates known. This Mg-rich clay is the low-temperature product of metasomatic reactions between the quartzofeldspathic wall rocks and serpentinite blocks in the <span class="hlt">fault</span>. These findings provide strong evidence that deformation of the mechanically unusual creeping portions of the San Andreas <span class="hlt">fault</span> system is controlled by the presence of weak minerals rather than by high fluid pressure or other proposed mechanisms. The combination of these measurements of <span class="hlt">fault</span> core strength with borehole observations yields a self-consistent picture of the stress state of the San Andreas <span class="hlt">fault</span> at the SAFOD site, in which the <span class="hlt">fault</span> is intrinsically weak in an otherwise strong crust. ?? 2011 Macmillan Publishers Limited. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.S54A..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.S54A..01S"><span><span class="hlt">Accurate</span> source <span class="hlt">location</span> from waves scattered by surface topography: Applications to the Nevada and North Korean test sites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Y.; Wang, N.; Bao, X.; Flinders, A. F.</p> <p>2016-12-01</p> <p>Scattered waves generated near the source contains energy converted from the near-field waves to the far-field propagating waves, which can be used to achieve <span class="hlt">location</span> accuracy beyond the diffraction limit. In this work, we apply a novel full-wave <span class="hlt">location</span> method that combines a grid-search algorithm with the 3D Green's tensor database to <span class="hlt">locate</span> the Non-Proliferation Experiment (NPE) at the Nevada test site and the North Korean nuclear tests. We use the first arrivals (Pn/Pg) and their immediate codas, which are likely dominated by waves scattered at the surface topography near the source, to determine the source <span class="hlt">location</span>. We investigate seismograms in the frequency of [1.0 2.0] Hz to reduce noises in the data and highlight topography scattered waves. High resolution topographic models constructed from 10 and 90 m grids are used for Nevada and North Korea, respectively. The reference velocity model is based on CRUST 1.0. We use the collocated-grid finite difference method on curvilinear grids to calculate the strain Green's tensor and obtain synthetic waveforms using source-receiver reciprocity. The `best' solution is found based on the least-square misfit between the observed and synthetic waveforms. To suppress random noises, an optimal weighting method for three-component seismograms is applied in misfit calculation. Our results show that the scattered waves are crucial in improving resolution and allow us to obtain <span class="hlt">accurate</span> solutions with a small number of stations. Since the scattered waves depends on topography, which is known at the wavelengths of regional seismic waves, our approach yields absolute, instead of relative, source <span class="hlt">locations</span>. We compare our solutions with those of USGS and other studies. Moreover, we use differential waveforms to <span class="hlt">locate</span> pairs of the North Korea tests from years 2006, 2009, 2013 and 2016 to further reduce the effects of unmodeled heterogeneities and errors in the reference velocity model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011IJTJE..28...31K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011IJTJE..28...31K"><span>GUI Type <span class="hlt">Fault</span> Diagnostic Program for a Turboshaft Engine Using Fuzzy and Neural Networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kong, Changduk; Koo, Youngju</p> <p>2011-04-01</p> <p>The helicopter to be operated in a severe flight environmental condition must have a very reliable propulsion system. On-line condition monitoring and <span class="hlt">fault</span> detection of the engine can promote reliability and availability of the helicopter propulsion system. A hybrid health monitoring program using Fuzzy Logic and Neural Network Algorithms can be proposed. In this hybrid method, the Fuzzy Logic identifies easily the <span class="hlt">faulted</span> components from engine measuring parameter changes, and the Neural Networks can quantify <span class="hlt">accurately</span> its identified <span class="hlt">faults</span>. In order to use effectively the <span class="hlt">fault</span> diagnostic system, a GUI (Graphical User Interface) type program is newly proposed. This program is composed of the real time monitoring part, the engine condition monitoring part and the <span class="hlt">fault</span> diagnostic part. The real time monitoring part can display measuring parameters of the study turboshaft engine such as power turbine inlet temperature, exhaust gas temperature, fuel flow, torque and gas generator speed. The engine condition monitoring part can evaluate the engine condition through comparison between monitoring performance parameters the base performance parameters analyzed by the base performance analysis program using look-up tables. The <span class="hlt">fault</span> diagnostic part can identify and quantify the single <span class="hlt">faults</span> the multiple <span class="hlt">faults</span> from the monitoring parameters using hybrid method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1436338-field-characterization-elastic-properties-across-fault-zone-reactivated-fluid-injection','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1436338-field-characterization-elastic-properties-across-fault-zone-reactivated-fluid-injection"><span>Field characterization of elastic properties across a <span class="hlt">fault</span> zone reactivated by fluid injection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Jeanne, Pierre; Guglielmi, Yves; Rutqvist, Jonny</p> <p></p> <p>In this paper, we studied the elastic properties of a <span class="hlt">fault</span> zone intersecting the Opalinus Clay formation at 300 m depth in the Mont Terri Underground Research Laboratory (Switzerland). Four controlled water injection experiments were performed in borehole straddle intervals set at successive <span class="hlt">locations</span> across the <span class="hlt">fault</span> zone. A three-component displacement sensor, which allowed capturing the borehole wall movements during injection, was used to estimate the elastic properties of representative <span class="hlt">locations</span> across the <span class="hlt">fault</span> zone, from the host rock to the damage zone to the <span class="hlt">fault</span> core. Young's moduli were estimated by both an analytical approach and numerical finite differencemore » modeling. Results show a decrease in Young's modulus from the host rock to the damage zone by a factor of 5 and from the damage zone to the <span class="hlt">fault</span> core by a factor of 2. In the host rock, our results are in reasonable agreement with laboratory data showing a strong elastic anisotropy characterized by the direction of the plane of isotropy parallel to the laminar structure of the shale formation. In the <span class="hlt">fault</span> zone, strong rotations of the direction of anisotropy can be observed. Finally, the plane of isotropy can be oriented either parallel to bedding (when few discontinuities are present), parallel to the direction of the main fracture family intersecting the zone, and possibly oriented parallel or perpendicular to the fractures critically oriented for shear reactivation (when repeated past rupture along this plane has created a zone).« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1436338-field-characterization-elastic-properties-across-fault-zone-reactivated-fluid-injection','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1436338-field-characterization-elastic-properties-across-fault-zone-reactivated-fluid-injection"><span>Field characterization of elastic properties across a <span class="hlt">fault</span> zone reactivated by fluid injection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Jeanne, Pierre; Guglielmi, Yves; Rutqvist, Jonny; ...</p> <p>2017-08-12</p> <p>In this paper, we studied the elastic properties of a <span class="hlt">fault</span> zone intersecting the Opalinus Clay formation at 300 m depth in the Mont Terri Underground Research Laboratory (Switzerland). Four controlled water injection experiments were performed in borehole straddle intervals set at successive <span class="hlt">locations</span> across the <span class="hlt">fault</span> zone. A three-component displacement sensor, which allowed capturing the borehole wall movements during injection, was used to estimate the elastic properties of representative <span class="hlt">locations</span> across the <span class="hlt">fault</span> zone, from the host rock to the damage zone to the <span class="hlt">fault</span> core. Young's moduli were estimated by both an analytical approach and numerical finite differencemore » modeling. Results show a decrease in Young's modulus from the host rock to the damage zone by a factor of 5 and from the damage zone to the <span class="hlt">fault</span> core by a factor of 2. In the host rock, our results are in reasonable agreement with laboratory data showing a strong elastic anisotropy characterized by the direction of the plane of isotropy parallel to the laminar structure of the shale formation. In the <span class="hlt">fault</span> zone, strong rotations of the direction of anisotropy can be observed. Finally, the plane of isotropy can be oriented either parallel to bedding (when few discontinuities are present), parallel to the direction of the main fracture family intersecting the zone, and possibly oriented parallel or perpendicular to the fractures critically oriented for shear reactivation (when repeated past rupture along this plane has created a zone).« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.T12A..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.T12A..01H"><span>A New Kinematic Model for Polymodal <span class="hlt">Faulting</span>: Implications for <span class="hlt">Fault</span> Connectivity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Healy, D.; Rizzo, R. E.</p> <p>2015-12-01</p> <p>Conjugate, or bimodal, <span class="hlt">fault</span> patterns dominate the geological literature on shear failure. Based on Anderson's (1905) application of the Mohr-Coulomb failure criterion, these patterns have been interpreted from all tectonic regimes, including normal, strike-slip and thrust (reverse) <span class="hlt">faulting</span>. However, a fundamental limitation of the Mohr-Coulomb failure criterion - and others that assume <span class="hlt">faults</span> form parallel to the intermediate principal stress - is that only plane strain can result from slip on the conjugate <span class="hlt">faults</span>. However, deformation in the Earth is widely accepted as being three-dimensional, with truly triaxial stresses and strains. Polymodal <span class="hlt">faulting</span>, with three or more sets of <span class="hlt">faults</span> forming and slipping simultaneously, can generate three-dimensional strains from truly triaxial stresses. Laboratory experiments and outcrop studies have verified the occurrence of the polymodal <span class="hlt">fault</span> patterns in nature. The connectivity of polymodal <span class="hlt">fault</span> networks differs significantly from conjugate <span class="hlt">fault</span> networks, and this presents challenges to our understanding of <span class="hlt">faulting</span> and an opportunity to improve our understanding of seismic hazards and fluid flow. Polymodal <span class="hlt">fault</span> patterns will, in general, have more connected nodes in 2D (and more branch lines in 3D) than comparable conjugate (bimodal) patterns. The anisotropy of permeability is therefore expected to be very different in rocks with polymodal <span class="hlt">fault</span> patterns in comparison to conjugate <span class="hlt">fault</span> patterns, and this has implications for the development of hydrocarbon reservoirs, the genesis of ore deposits and the management of aquifers. In this contribution, I assess the published evidence and models for polymodal <span class="hlt">faulting</span> before presenting a novel kinematic model for general triaxial strain in the brittle field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......273B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......273B"><span>Transfer zones in listric normal <span class="hlt">fault</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bose, Shamik</p> <p></p> <p>Listric normal <span class="hlt">faults</span> are common in passive margin settings where sedimentary units are detached above weaker lithological units, such as evaporites or are driven by basal structural and stratigraphic discontinuities. The geometries and styles of <span class="hlt">faulting</span> vary with the types of detachment and form landward and basinward dipping <span class="hlt">fault</span> systems. Complex transfer zones therefore develop along the terminations of adjacent <span class="hlt">faults</span> where deformation is accommodated by secondary <span class="hlt">faults</span>, often below seismic resolution. The rollover geometry and secondary <span class="hlt">faults</span> within the hanging wall of the major <span class="hlt">faults</span> also vary with the styles of <span class="hlt">faulting</span> and contribute to the complexity of the transfer zones. This study tries to understand the controlling factors for the formation of the different styles of listric normal <span class="hlt">faults</span> and the different transfer zones formed within them, by using analog clay experimental models. Detailed analyses with respect to <span class="hlt">fault</span> orientation, density and connectivity have been performed on the experiments in order to gather insights on the structural controls and the resulting geometries. A new high resolution 3D laser scanning technology has been introduced to scan the surfaces of the clay experiments for <span class="hlt">accurate</span> measurements and 3D visualizations. Numerous examples from the Gulf of Mexico have been included to demonstrate and geometrically compare the observations in experiments and real structures. A salt cored convergent transfer zone from the South Timbalier Block 54, offshore Louisiana has been analyzed in detail to understand the evolutionary history of the region, which helps in deciphering the kinematic growth of similar structures in the Gulf of Mexico. The dissertation is divided into three chapters, written in a journal article format, that deal with three different aspects in understanding the listric normal <span class="hlt">fault</span> systems and the transfer zones so formed. The first chapter involves clay experimental models to understand the <span class="hlt">fault</span> patterns in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920059468&hterms=fault+tree+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfault%2Btree%2Banalysis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920059468&hterms=fault+tree+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dfault%2Btree%2Banalysis"><span><span class="hlt">Fault</span> tree models for <span class="hlt">fault</span> tolerant hypercube multiprocessors</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Boyd, Mark A.; Tuazon, Jezus O.</p> <p>1991-01-01</p> <p>Three candidate <span class="hlt">fault</span> tolerant hypercube architectures are modeled, their reliability analyses are compared, and the resulting implications of these methods of incorporating <span class="hlt">fault</span> tolerance into hypercube multiprocessors are discussed. In the course of performing the reliability analyses, the use of HARP and <span class="hlt">fault</span> trees in modeling sequence dependent system behaviors is demonstrated.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26646282','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26646282"><span><span class="hlt">Fault</span> Tree Analysis.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McElroy, Lisa M; Khorzad, Rebeca; Rowe, Theresa A; Abecassis, Zachary A; Apley, Daniel W; Barnard, Cynthia; Holl, Jane L</p> <p></p> <p>The purpose of this study was to use <span class="hlt">fault</span> tree analysis to evaluate the adequacy of quality reporting programs in identifying root causes of postoperative bloodstream infection (BSI). A systematic review of the literature was used to construct a <span class="hlt">fault</span> tree to evaluate 3 postoperative BSI reporting programs: National Surgical Quality Improvement Program (NSQIP), Centers for Medicare and Medicaid Services (CMS), and The Joint Commission (JC). The literature review revealed 699 eligible publications, 90 of which were used to create the <span class="hlt">fault</span> tree containing 105 <span class="hlt">faults</span>. A total of 14 identified <span class="hlt">faults</span> are currently mandated for reporting to NSQIP, 5 to CMS, and 3 to JC; 2 or more programs require 4 identified <span class="hlt">faults</span>. The <span class="hlt">fault</span> tree identifies numerous contributing <span class="hlt">faults</span> to postoperative BSI and reveals substantial variation in the requirements and ability of national quality data reporting programs to capture these potential <span class="hlt">faults</span>. Efforts to prevent postoperative BSI require more comprehensive data collection to identify the root causes and develop high-reliability improvement strategies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Tectp.726...43M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Tectp.726...43M"><span>Magnetotelluric study to characterize Kachchh Mainland <span class="hlt">Fault</span> (KMF) and Katrol Hill <span class="hlt">Fault</span> (KHF) in the western part of Kachchh region of Gujarat, India</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mohan, Kapil; Chaudhary, Peush; Patel, Pruthul; Chaudhary, B. S.; Chopra, Sumer</p> <p>2018-02-01</p> <p>The Kachchh Mainland <span class="hlt">Fault</span> (KMF) is a major E-W trending <span class="hlt">fault</span> in the Kachchh region of Gujarat extending >150 km from Lakhpat village in the west to the Bhachau town in the east. The Katrol Hill <span class="hlt">Fault</span> (KHF) is an E-W trending intrabasinal <span class="hlt">fault</span> <span class="hlt">located</span> in the central region of Kachchh Basin and the south of KMF. The western parts of both of the <span class="hlt">faults</span> are characterized, and the sediment thickness has been estimated in the region using a Magnetotelluric (MT) survey at 17 sites along a 55 km long north-south profile with a site spacing of 2-3 km. The analysis reveals that the maximum sediment thickness is 2.3 km (Quaternary, Tertiary, and Mesozoic) in the region, out of which, the Mesozoic sediments feature a maximum thickness of 2 km. The estimated sediment thickness is found consistent with the thickness suggested by a deep borehole (depth approx. 2.5 km) drilled by Oil and Natural Gas Corporation (ONGC) at Nirona (Northern part of the study area). From 2-D inversion of the MT data, three conductive zones are identified from north to south. The first conductive zone is dipping nearly vertical down to 7-8 km depth. It becomes north-dipping below 8 km depth and is inferred as KMF. The second conductive zone is found steeply dipping into the southern limbs near Manjal village (28 km south of Nirona), which is inferred as the KHF. A vertical-dipping (down to 20 km depth) conductive zone has also been observed near Ulat village, <span class="hlt">located</span> 16 km north of Manjal village and 12 km south of Nirona village. This conductive zone becomes listric north-dipping beyond 20 km depth. It is reported first time by a Geophysical survey in the region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900012989','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900012989"><span>NASA ground terminal communication equipment automated <span class="hlt">fault</span> isolation expert systems</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tang, Y. K.; Wetzel, C. R.</p> <p>1990-01-01</p> <p>The prototype expert systems are described that diagnose the Distribution and Switching System I and II (DSS1 and DSS2), Statistical Multiplexers (SM), and Multiplexer and Demultiplexer systems (MDM) at the NASA Ground Terminal (NGT). A system level <span class="hlt">fault</span> isolation expert system monitors the activities of a selected data stream, verifies that the <span class="hlt">fault</span> exists in the NGT and identifies the faulty equipment. Equipment level <span class="hlt">fault</span> isolation expert systems are invoked to isolate the <span class="hlt">fault</span> to a Line Replaceable Unit (LRU) level. Input and sometimes output data stream activities for the equipment are available. The system level <span class="hlt">fault</span> isolation expert system compares the equipment input and output status for a data stream and performs loopback tests (if necessary) to isolate the faulty equipment. The equipment level <span class="hlt">fault</span> isolation system utilizes the process of elimination and/or the maintenance personnel's <span class="hlt">fault</span> isolation experience stored in its knowledge base. The DSS1, DSS2 and SM <span class="hlt">fault</span> isolation systems, using the knowledge of the current equipment configuration and the equipment circuitry issues a set of test connections according to the predefined rules. The faulty component or board can be identified by the expert system by analyzing the test results. The MDM <span class="hlt">fault</span> isolation system correlates the failure symptoms with the faulty component based on maintenance personnel experience. The faulty component can be determined by knowing the failure symptoms. The DSS1, DSS2, SM, and MDM equipment simulators are implemented in PASCAL. The DSS1 <span class="hlt">fault</span> isolation expert system was converted to C language from VP-Expert and integrated into the NGT automation software for offline switch diagnoses. Potentially, the NGT <span class="hlt">fault</span> isolation algorithms can be used for the DSS1, SM, amd MDM <span class="hlt">located</span> at Goddard Space Flight Center (GSFC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T21A2800L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T21A2800L"><span>Syn-Extensional Constrictional Folding of the Gwoira Rider Block, a Large <span class="hlt">Fault</span>-Bounded Slice Atop the Mai'iu Low-Angle Normal <span class="hlt">Fault</span>, Woodlark Rift.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Little, T. A.; Webber, S. M.; Norton, K. P.; Mizera, M.; Oesterle, J.; Ellis, S. M.</p> <p>2016-12-01</p> <p>The Mai'iu <span class="hlt">Fault</span> is an active and corrugated low-angle normal <span class="hlt">fault</span> (LANF) in Woodlark Rift, Eastern Papua New Guinea, which dips 21° NNE, accommodating rapid N-S extension. The Gwoira rider block is a large <span class="hlt">fault</span>-bounded sedimentary slice comprising the Gwoira Conglomerate, <span class="hlt">located</span> within a large synformal megamullion in the Mai'iu <span class="hlt">Fault</span> surface. The Gwoira Conglomerate was originally deposited on the Mai'iu <span class="hlt">Fault</span> hanging wall concurrent with extension, and has since been buried to a maximum depth of 1600-2100 m (evidenced by vitrinite reflectance data), back-tilted, and synformally folded. Both the Gwoira Conglomerate (former hanging wall) and mylonitic foliation (footwall) of the Mai'iu <span class="hlt">Fault</span> have been shortened E-W, perpendicular to the extension direction. We show that E-W synformal folding of the Gwoira Conglomerate was concurrent with ongoing sedimentation and extension on the Mai'iu <span class="hlt">Fault</span>. Structurally shallower Gwoira Conglomerate strata are folded less than deeper strata, indicating that folding was progressively accrued concurrent with N-S extension. We also show that abandonment of the inactive strand of the Mai'iu <span class="hlt">Fault</span> in favor of the Gwoira <span class="hlt">Fault</span>, which resulted in formation of the Gwoira rider block, occurred in response to progressive megamullion amplification and resultant misorientation of the inactive strand of the Mai'iu <span class="hlt">Fault</span>. We attribute E-W folding to extension-perpendicular constriction. This is consistent with observations of outcrop-scale conjugate strike-slip <span class="hlt">faults</span> that deform the footwall and hanging wall of the Mai'iu <span class="hlt">Fault</span>, and accommodate E-W shortening. Constrictional folding remains active in the near-surface as evidenced by synformal tilting of inferred Late Quaternary fluvial terraces atop the Gwoira rider block. This sequence of progressive constrictional folding is dated using 26Al/10Be terrestrial cosmogenic nuclide burial dating of the Gwoira Conglomerate. Finally, because rider block formation records abandonment of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PApGe.174.2925G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PApGe.174.2925G"><span><span class="hlt">Fault</span> Slip Distribution of the 2016 Fukushima Earthquake Estimated from Tsunami Waveforms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gusman, Aditya Riadi; Satake, Kenji; Shinohara, Masanao; Sakai, Shin'ichi; Tanioka, Yuichiro</p> <p>2017-08-01</p> <p>The 2016 Fukushima normal-<span class="hlt">faulting</span> earthquake (Mjma 7.4) occurred 40 km off the coast of Fukushima within the upper crust. The earthquake generated a moderate tsunami which was recorded by coastal tide gauges and offshore pressure gauges. First, the sensitivity of tsunami waveforms to <span class="hlt">fault</span> dimensions and depths was examined and the best size and depth were determined. Tsunami waveforms computed based on four available focal mechanisms showed that a simple <span class="hlt">fault</span> striking northeast-southwest and dipping southeast (strike = 45°, dip = 41°, rake = -95°) yielded the best fit to the observed waveforms. This <span class="hlt">fault</span> geometry was then used in a tsunami waveform inversion to estimate the <span class="hlt">fault</span> slip distribution. A large slip of 3.5 m was <span class="hlt">located</span> near the surface and the major slip region covered an area of 20 km × 20 km. The seismic moment, calculated assuming a rigidity of 2.7 × 1010 N/m2 was 3.70 × 1019 Nm, equivalent to Mw = 7.0. This is slightly larger than the moments from the moment tensor solutions (Mw 6.9). Large secondary tsunami peaks arrived approximately an hour after clear initial peaks were recorded by the offshore pressure gauges and the Sendai and Ofunato tide gauges. Our tsunami propagation model suggests that the large secondary tsunami signals were from tsunami waves reflected off the Fukushima coast. A rather large tsunami amplitude of 75 cm at Kuji, about 300 km north of the source, was comparable to those recorded at stations <span class="hlt">located</span> much closer to the epicenter, such as Soma and Onahama. Tsunami simulations and ray tracing for both real and artificial bathymetry indicate that a significant portion of the tsunami wave was refracted to the coast <span class="hlt">located</span> around Kuji and Miyako due to bathymetry effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70157058','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70157058"><span>Deformation of the 2002 Denali <span class="hlt">Fault</span> earthquakes, mapped by Radarsat-1 interferometry</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lu, Zhong; Wright, Tim; Wicks, Chuck</p> <p>2003-01-01</p> <p>The magnitude 7.9 earthquake that struck central Alaska on 3 November 2002 was the largest strike-slip earthquake in North America for more than 150 years. The earthquake ruptured about 340 km of the Denali <span class="hlt">Fault</span> system with observed right-lateral offsets of up to 9 m [Eberhart-Phillips et al., 2003] (Figure l). The rupture initiated with slip on a previously unknown thrust <span class="hlt">fault</span>, the 40-km-long Susitna Glacier <span class="hlt">Fault</span>. The rupture propagated eastward for about 220 km along the right-lateral Denali <span class="hlt">Fault</span> where right-lateral slip averaged ˜5 m, before stepping southeastward onto the Totschunda <span class="hlt">Fault</span> for about 70 km, with offsets as large as 2 m. The 3 November earthquake was preceded by a magnitude 6.7 shock on 23 October—the Nenana Mountain Earthquake—which was <span class="hlt">located</span> about 25 km to the west of the 3 November earthquake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017IJC....90.2227Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017IJC....90.2227Q"><span><span class="hlt">Fault</span>-tolerant cooperative output regulation for multi-vehicle systems with sensor <span class="hlt">faults</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, Liguo; He, Xiao; Zhou, D. H.</p> <p>2017-10-01</p> <p>This paper presents a unified framework of <span class="hlt">fault</span> diagnosis and <span class="hlt">fault</span>-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor <span class="hlt">faults</span>. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor <span class="hlt">faults</span>. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised <span class="hlt">fault</span> diagnosis scheme is designed to cope with sensor <span class="hlt">faults</span> occurring in followers. A residual generator is developed to detect sensor <span class="hlt">faults</span> of each follower, and a bank of <span class="hlt">fault</span>-matching estimators are proposed to isolate and estimate sensor <span class="hlt">faults</span> of each follower. Unlike the current distributed <span class="hlt">fault</span> diagnosis for multi-vehicle systems, the presented decentralised <span class="hlt">fault</span> diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor <span class="hlt">fault</span> estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70048667','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70048667"><span>Crustal structure and <span class="hlt">fault</span> geometry of the 2010 Haiti earthquake from temporary seismometer deployments</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Douilly, Roby; Haase, Jennifer S.; Ellsworth, William L.; Bouin, Marie‐Paule; Calais, Eric; Symithe, Steeve J.; Armbruster, John G.; Mercier de Lépinay, Bernard; Deschamps, Anne; Mildor, Saint‐Louis; Meremonte, Mark E.; Hough, Susan E.</p> <p>2013-01-01</p> <p>Haiti has been the locus of a number of large and damaging historical earthquakes. The recent 12 January 2010 Mw 7.0 earthquake affected cities that were largely unprepared, which resulted in tremendous losses. It was initially assumed that the earthquake ruptured the Enriquillo Plantain Garden <span class="hlt">fault</span> (EPGF), a major active structure in southern Haiti, known from geodetic measurements and its geomorphic expression to be capable of producing M 7 or larger earthquakes. Global Positioning Systems (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data, however, showed that the event ruptured a previously unmapped <span class="hlt">fault</span>, the Léogâne <span class="hlt">fault</span>, a north‐dipping oblique transpressional <span class="hlt">fault</span> <span class="hlt">located</span> immediately north of the EPGF. Following the earthquake, several groups installed temporary seismic stations to record aftershocks, including ocean‐bottom seismometers on either side of the EPGF. We use data from the complete set of stations deployed after the event, on land and offshore, to relocate all aftershocks from 10 February to 24 June 2010, determine a 1D regional crustal velocity model, and calculate focal mechanisms. The aftershock <span class="hlt">locations</span> from the combined dataset clearly delineate the Léogâne <span class="hlt">fault</span>, with a geometry close to that inferred from geodetic data. Its strike and dip closely agree with the global centroid moment tensor solution of the mainshock but with a steeper dip than inferred from previous finite <span class="hlt">fault</span> inversions. The aftershocks also delineate a structure with shallower southward dip offshore and to the west of the rupture zone, which could indicate triggered seismicity on the offshore Trois Baies reverse <span class="hlt">fault</span>. We use first‐motion focal mechanisms to clarify the relationship of the <span class="hlt">fault</span> geometry to the triggered aftershocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28290529','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28290529"><span>Late Quaternary <span class="hlt">faulting</span> in the Sevier Desert driven by magmatism.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stahl, T; Niemi, N A</p> <p>2017-03-14</p> <p>Seismic hazard in continental rifts varies as a function of strain accommodation by tectonic or magmatic processes. The nature of <span class="hlt">faulting</span> in the Sevier Desert, <span class="hlt">located</span> in eastern Basin and Range of central Utah, and how this <span class="hlt">faulting</span> relates to the Sevier Desert Detachment low-angle normal <span class="hlt">fault</span>, have been debated for nearly four decades. Here, we show that the geodetic signal of extension across the eastern Sevier Desert is best explained by magma-assisted rifting associated with Plio-Pleistocene volcanism. GPS velocities from 14 continuous sites across the region are best-fit by interseismic strain accumulation on the southern Wasatch <span class="hlt">Fault</span> at c. 3.4 mm yr -1 with a c. 0.5 mm yr -1 tensile dislocation opening in the eastern Sevier Desert. The characteristics of surface deformation from field surveys are consistent with dike-induced <span class="hlt">faulting</span> and not with <span class="hlt">faults</span> soling into an active detachment. Geologic extension rates of c. 0.6 mm yr -1 over the last c. 50 kyr in the eastern Sevier Desert are consistent with the rates estimated from the geodetic model. Together, these findings suggest that Plio-Pleistocene extension is not likely to have been accommodated by low-angle normal <span class="hlt">faulting</span> on the Sevier Desert Detachment and is instead accomplished by strain localization in a zone of narrow, magma-assisted rifting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5349561','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5349561"><span>Late Quaternary <span class="hlt">faulting</span> in the Sevier Desert driven by magmatism</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Stahl, T.; Niemi, N. A.</p> <p>2017-01-01</p> <p>Seismic hazard in continental rifts varies as a function of strain accommodation by tectonic or magmatic processes. The nature of <span class="hlt">faulting</span> in the Sevier Desert, <span class="hlt">located</span> in eastern Basin and Range of central Utah, and how this <span class="hlt">faulting</span> relates to the Sevier Desert Detachment low-angle normal <span class="hlt">fault</span>, have been debated for nearly four decades. Here, we show that the geodetic signal of extension across the eastern Sevier Desert is best explained by magma-assisted rifting associated with Plio-Pleistocene volcanism. GPS velocities from 14 continuous sites across the region are best-fit by interseismic strain accumulation on the southern Wasatch <span class="hlt">Fault</span> at c. 3.4 mm yr−1 with a c. 0.5 mm yr−1 tensile dislocation opening in the eastern Sevier Desert. The characteristics of surface deformation from field surveys are consistent with dike-induced <span class="hlt">faulting</span> and not with <span class="hlt">faults</span> soling into an active detachment. Geologic extension rates of c. 0.6 mm yr−1 over the last c. 50 kyr in the eastern Sevier Desert are consistent with the rates estimated from the geodetic model. Together, these findings suggest that Plio-Pleistocene extension is not likely to have been accommodated by low-angle normal <span class="hlt">faulting</span> on the Sevier Desert Detachment and is instead accomplished by strain localization in a zone of narrow, magma-assisted rifting. PMID:28290529</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MSSP...75..544D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MSSP...75..544D"><span>Extraction of <span class="hlt">fault</span> component from abnormal sound in diesel engines using acoustic signals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dayong, Ning; Changle, Sun; Yongjun, Gong; Zengmeng, Zhang; Jiaoyi, Hou</p> <p>2016-06-01</p> <p>In this paper a method for extracting <span class="hlt">fault</span> components from abnormal acoustic signals and automatically diagnosing diesel engine <span class="hlt">faults</span> is presented. The method named dislocation superimposed method (DSM) is based on the improved random decrement technique (IRDT), differential function (DF) and correlation analysis (CA). The aim of DSM is to linearly superpose multiple segments of abnormal acoustic signals because of the waveform similarity of faulty components. The method uses sample points at the beginning of time when abnormal sound appears as the starting position for each segment. In this study, the abnormal sound belonged to shocking faulty type; thus, the starting position searching method based on gradient variance was adopted. The coefficient of similar degree between two same sized signals is presented. By comparing with a similar degree, the extracted <span class="hlt">fault</span> component could be judged automatically. The results show that this method is capable of <span class="hlt">accurately</span> extracting the <span class="hlt">fault</span> component from abnormal acoustic signals induced by faulty shocking type and the extracted component can be used to identify the <span class="hlt">fault</span> type.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.T31A1786K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.T31A1786K"><span><span class="hlt">Faulting</span>, Seismicity and Stress Interaction in the Salton Sea Region of Southern California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kilb, D. L.; Brothers, D. S.; Lin, G.; Kent, G.; Newman, R. L.; Driscoll, N.</p> <p>2009-12-01</p> <p>The Salton Sea region in southern California provides an ideal <span class="hlt">location</span> to study the relationship between transcurrent and extensional motion in the northern Gulf of California margin, allowing us to investigate the spatial and temporal interaction of <span class="hlt">faults</span> in the area and better understand their kinematics. In this region, the San Andreas <span class="hlt">Fault</span> (SAF) and Imperial <span class="hlt">Fault</span> present two major transform <span class="hlt">faults</span> separated by the Salton Sea transtensional domain. Earthquakes over magnitude 4 in this area almost always have associated aftershock sequences. Recent seismic reflection surveys in the Salton Sea reveal that the majority of <span class="hlt">faults</span> under the southern Salton Sea trend ~N15°E, appear normal-dominant and have very minimal associated microseismicity. These normal <span class="hlt">faults</span> rupture every 100-300 years in large earthquakes and most of the nearby microseismicity <span class="hlt">locates</span> east of the mapped surface traces. For example, there is profuse microseismicity in the Brawley Seismic Zone (BSZ), which is coincident with the southern terminus of the SAF as it extends offshore into the Salton Sea. Earthquakes in the BSZ are dominantly swarm-like, occurring along short (<5 km) ~N45°E oriented sinistral and N35°W oriented dextral <span class="hlt">fault</span> planes. This mapped seismicity makes a rung-and-ladder pattern. In an effort to reconcile differences between processes at the surface and those at seismogenic depths we integrate near surface <span class="hlt">fault</span> kinematics, geometry and paleoseismic history with seismic data. We identify linear and planer trends in these data (20 near surface <span class="hlt">faults</span>, >20,000 relocated earthquakes and >2,000 earthquake focal mechanisms) and when appropriate estimate the <span class="hlt">fault</span> strike and dip using principal component analysis. With our more detailed image of the <span class="hlt">fault</span> structure we assess how static stress changes imparted by magnitude ~6.0 ruptures along N15E oriented normal <span class="hlt">faults</span> beneath the Salton Sea can modulate the stress field in the BSZ and along the SAF. These tests include</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.S21E..05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.S21E..05T"><span>New Insights on Seismicity and the Velocity Structure beneath the Western Segment of the North Anatolian <span class="hlt">Fault</span> Zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teoman, U.; Altuncu Poyraz, S.; Kahraman, M.; Mutlu, A. K.; Cambaz, D.; Turkelli, N.; Thompson, D. A.; Rost, S.; Houseman, G. A.; Utkucu, M.</p> <p>2014-12-01</p> <p>To extensively investigate the upper crustal structure beneath the western segment of the North Anatolian <span class="hlt">Fault</span> Zone (NAFZ) in Sakarya and the surroundings, a temporary seismic network consisting of 70 stations (with nearly 7km station spacing) was deployed in early May 2012 and operated for 18 months during the Faultlab experiment encompassing both the northern and southern strands of the <span class="hlt">fault</span> in between the area of 1999 İzmit and Düzce mainshock ruptures. With the help of this new and extensive data set, our main objective is to provide new insights on the most recent micro-seismic activity and the velocity structure beneath the region. Out of 2437 events contaminated by the explosions, we extracted 1344 well <span class="hlt">located</span> earthquakes with a total of 31595 P and 18512 S phase readings which lead to an avarage Vp/Vs ratio of ~1.82 extracted from the wadati diagram. The enhanced station coverage decreased the magnitude threshold to 0.1 where the horizontal and vertical <span class="hlt">location</span> errors did not exceed 0.5 km and 2.0 km, respectively. Average RMS values were calculated within the range of 0.05-0.4 seconds. We observed significant seismic activity along both branches of the <span class="hlt">fault</span> where the depth of the seismogenic zone was confined to 15 km. Focal parameters of 41 earthquakes with magnitudes greater than 1.8 were also determined using both Regional Moment Tensor Inversion and P first arrival time methods. Focal mechanism solutions confirm that Sakarya and its vicinity could be defined by a compressional regime showing a primarily oblique-slip motion character. Furthermore, we selected the earthquakes recorded by at least 8 stations with azimuthal gaps less than 200° for the ongoing tomographic inversion that would enable us to <span class="hlt">accurately</span> map the complex upper crustal velocity structure with high resolution beneath this segment of the NAFZ.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/1242337-development-evaluation-virtual-refrigerant-mass-flow-sensors-fault-detection-diagnostics','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/1242337-development-evaluation-virtual-refrigerant-mass-flow-sensors-fault-detection-diagnostics"><span>Development and evaluation of virtual refrigerant mass flow sensors for <span class="hlt">fault</span> detection and diagnostics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Kim, Woohyun; Braun, J.</p> <p></p> <p>Refrigerant mass flow rate is an important measurement for monitoring equipment performance and enabling <span class="hlt">fault</span> detection and diagnostics. However, a traditional mass flow meter is expensive to purchase and install. A virtual refrigerant mass flow sensor (VRMF) uses a mathematical model to estimate flow rate using low-cost measurements and can potentially be implemented at low cost. This study evaluates three VRMFs for estimating refrigerant mass flow rate. The first model uses a compressor map that relates refrigerant flow rate to measurements of inlet and outlet pressure, and inlet temperature measurements. The second model uses an energy-balance method on the compressormore » that uses a compressor map for power consumption, which is relatively independent of compressor <span class="hlt">faults</span> that influence mass flow rate. The third model is developed using an empirical correlation for an electronic expansion valve (EEV) based on an orifice equation. The three VRMFs are shown to work well in estimating refrigerant mass flow rate for various systems under <span class="hlt">fault</span>-free conditions with less than 5% RMS error. Each of the three mass flow rate estimates can be utilized to diagnose and track the following <span class="hlt">faults</span>: 1) loss of compressor performance, 2) fouled condenser or evaporator filter, 3) faulty expansion device, respectively. For example, a compressor refrigerant flow map model only provides an <span class="hlt">accurate</span> estimation when the compressor operates normally. When a compressor is not delivering the expected flow due to a leaky suction or discharge valve or other internal <span class="hlt">fault</span>, the energy-balance or EEV model can provide <span class="hlt">accurate</span> flow estimates. In this paper, the flow differences provide an indication of loss of compressor performance and can be used for <span class="hlt">fault</span> detection and diagnostics.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Tectp.733..257L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Tectp.733..257L"><span>Stability of <span class="hlt">faults</span> with heterogeneous friction properties and effective normal stress</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, Yingdi; Ampuero, Jean-Paul</p> <p>2018-05-01</p> <p>Abundant geological, seismological and experimental evidence of the heterogeneous structure of natural <span class="hlt">faults</span> motivates the theoretical and computational study of the mechanical behavior of heterogeneous frictional <span class="hlt">fault</span> interfaces. <span class="hlt">Fault</span> zones are composed of a mixture of materials with contrasting strength, which may affect the spatial variability of seismic coupling, the <span class="hlt">location</span> of high-frequency radiation and the diversity of slip behavior observed in natural <span class="hlt">faults</span>. To develop a quantitative understanding of the effect of strength heterogeneity on the mechanical behavior of <span class="hlt">faults</span>, here we investigate a <span class="hlt">fault</span> model with spatially variable frictional properties and pore pressure. Conceptually, this model may correspond to two rough surfaces in contact along discrete asperities, the space in between being filled by compressed gouge. The asperities have different permeability than the gouge matrix and may be hydraulically sealed, resulting in different pore pressure. We consider <span class="hlt">faults</span> governed by rate-and-state friction, with mixtures of velocity-weakening and velocity-strengthening materials and contrasts of effective normal stress. We systematically study the diversity of slip behaviors generated by this model through multi-cycle simulations and linear stability analysis. The <span class="hlt">fault</span> can be either stable without spontaneous slip transients, or unstable with spontaneous rupture. When the <span class="hlt">fault</span> is unstable, slip can rupture either part or the entire <span class="hlt">fault</span>. In some cases the <span class="hlt">fault</span> alternates between these behaviors throughout multiple cycles. We determine how the <span class="hlt">fault</span> behavior is controlled by the proportion of velocity-weakening and velocity-strengthening materials, their relative strength and other frictional properties. We also develop, through heuristic approximations, closed-form equations to predict the stability of slip on heterogeneous <span class="hlt">faults</span>. Our study shows that a <span class="hlt">fault</span> model with heterogeneous materials and pore pressure contrasts is a viable framework</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080004301','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080004301"><span><span class="hlt">Fault</span> detection and bypass in a sequence information signal processor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peterson, John C. (Inventor); Chow, Edward T. (Inventor)</p> <p>1992-01-01</p> <p>The invention comprises a plurality of scan registers, each such register respectively associated with a processor element; an on-chip comparator, encoder and <span class="hlt">fault</span> bypass register. Each scan register generates a unitary signal the logic state of which depends on the correctness of the input from the previous processor in the systolic array. These unitary signals are input to a common comparator which generates an output indicating whether or not an error has occurred. These unitary signals are also input to an encoder which identifies the <span class="hlt">location</span> of any <span class="hlt">fault</span> detected so that an appropriate multiplexer can be switched to bypass the faulty processor element. Input scan data can be readily programmed to fully exercise all of the processor elements so that no <span class="hlt">fault</span> can remain undetected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.477...84S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.477...84S"><span>Frictional stability and earthquake triggering during fluid pressure stimulation of an experimental <span class="hlt">fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scuderi, M. M.; Collettini, C.; Marone, C.</p> <p>2017-11-01</p> <p>It is widely recognized that the significant increase of M > 3.0 earthquakes in Western Canada and the Central United States is related to underground fluid injection. Following injection, fluid overpressure lubricates the <span class="hlt">fault</span> and reduces the effective normal stress that holds the <span class="hlt">fault</span> in place, promoting slip. Although, this basic physical mechanism for earthquake triggering and <span class="hlt">fault</span> slip is well understood, there are many open questions related to induced seismicity. Models of earthquake nucleation based on rate- and state-friction predict that fluid overpressure should stabilize <span class="hlt">fault</span> slip rather than trigger earthquakes. To address this controversy, we conducted laboratory creep experiments to monitor <span class="hlt">fault</span> slip evolution at constant shear stress while the effective normal stress was systematically reduced via increasing fluid pressure. We sheared layers of carbonate-bearing <span class="hlt">fault</span> gouge in a double direct shear configuration within a true-triaxial pressure vessel. We show that <span class="hlt">fault</span> slip evolution is controlled by the stress state acting on the <span class="hlt">fault</span> and that fluid pressurization can trigger dynamic instability even in cases of rate strengthening friction, which should favor aseismic creep. During fluid pressurization, when shear and effective normal stresses reach the failure condition, accelerated creep occurs in association with <span class="hlt">fault</span> dilation; further pressurization leads to an exponential acceleration with <span class="hlt">fault</span> compaction and slip localization. Our work indicates that <span class="hlt">fault</span> weakening induced by fluid pressurization can overcome rate strengthening friction resulting in fast acceleration and earthquake slip. Our work points to modifications of the standard model for earthquake nucleation to account for the effect of fluid overpressure and to <span class="hlt">accurately</span> predict the seismic risk associated with fluid injection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2015/1122/pdf/ofr20151122.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2015/1122/pdf/ofr20151122.pdf"><span>Trench logs, terrestrial lidar system imagery, and radiocarbon data from the kilometer-62 site on the Greenville <span class="hlt">Fault</span>, southeastern Alameda County, California, 2014</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lienkaemper, James J.; DeLong, Stephen B.; Avdievitch, Nikita N.; Pickering, Alexandra J; Guilderson, Thomas P.</p> <p>2015-01-01</p> <p>In 2014, we investigated an abrupt 8.5-meter (m), right-laterally deflected stream channel <span class="hlt">located</span> near the Greenville <span class="hlt">Fault</span> in southeastern Alameda County, California (-121.56224° E, 37.53430° N) that we discovered using 0.5-m resolution, 2011 aerial lidar imagery flown along the active <span class="hlt">fault</span> trace. Prior to trenching we surveyed the site using a terrestrial lidar system (TLS) to document the exact geomorphic expression of this deflected stream channel before excavating a trench adjacent to it. We trenched perpendicular to the <span class="hlt">fault</span> hoping to document the prehistoric history of earthquake ruptures along the <span class="hlt">fault</span>. However, the alluvial stratigraphy that we document in these trench logs shows conclusively that this trench did not expose any active <span class="hlt">fault</span> trace. Using other local geomorphic evidence for the <span class="hlt">fault</span> <span class="hlt">location</span>, a straight <span class="hlt">fault</span> scarp immediately north of this stream projects slightly upslope of the west end of our trench and may be the actual <span class="hlt">location</span> of the active <span class="hlt">fault</span> trace. Five radiocarbon samples establish age control for the alluvial sequence documented in the trench, which may in the future be useful in constraining the long-term slip rate of the Greenville <span class="hlt">Fault</span>. The deflection had been caused by an abrupt nontectonic termination of unit u30, a relatively thick (0.15–0.35 m) silt that is more erosion resistant than the adjacent cohesionless sand and gravel. </p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA112960','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA112960"><span>MX Siting Investigation. <span class="hlt">Faults</span> and Lineaments in the MX Siting Region, Nevada and Utah. Volume I.</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1981-11-06</p> <p>indicate favorable mineral potential. Verifi- cation, Operational Base, and Shelter Layout studies used <span class="hlt">fault</span> and lineament data to assist in determining... shelter <span class="hlt">locations</span> were situated so as to avoid <span class="hlt">faults</span> but roads were allowed to cross some <span class="hlt">faults</span> and lineaments because it is generally infeasible, if not... Cordillera in the Western United States, in Smith, R. B., and Eaton, G. P., eds., Cenozoic tectonics - and regional geophysics of the western Cordillera</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/biblio/5807059-faulting-thebes-gap-mo-ill-implications-new-madrid-tectonism','SCIGOV-STC'); return false;" href="https://www.osti.gov/biblio/5807059-faulting-thebes-gap-mo-ill-implications-new-madrid-tectonism"><span><span class="hlt">Faulting</span> at Thebes Gap, Mo. -Ill. : Implications for New Madrid tectonism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/search">DOE Office of Scientific and Technical Information (OSTI.GOV)</a></p> <p>Harrison, R.W.; Schultz, A.P.</p> <p>1992-01-01</p> <p>Recent geologic mapping in the Thebes Gap area has identified numerous NNE- and NE-striking <span class="hlt">faults</span> having a long-lived and complex structural history. The <span class="hlt">faults</span> are <span class="hlt">located</span> in an area of moderate recent seismicity at the northern margin of the Mississippi embayment, approximately 45 km north of the New Madrid seismic zone. Earliest deformation occurred along dextral strike-slip <span class="hlt">faults</span> constrained as post-Devonian and pre-Cretaceous. Uplift and erosion of all Carboniferous strata suggest that this <span class="hlt">faulting</span> is related to development of the Pascola arch (Ouachita orogeny). This early deformation is characterized by strongly <span class="hlt">faulted</span> and folded Ordovician through Devonian rocks overlain inmore » places with angular unconformity by undeformed Cretaceous strata. Elsewhere, younger deformation involves Paleozoic, Cretaceous, Paleocene, and Eocene formations. These units have experienced both minor high-angle normal <span class="hlt">faulting</span> and major, dextral strike-slip <span class="hlt">faulting</span>. Quaternary-Tertiary Mounds Gravel is also involved in the latest episode of strike-slip deformation. Enechelon north-south folds, antithetic R[prime] shears, and drag folds indicate right-lateral motion. Characteristic positive and negative flower structures are commonly revealed in cross section. Right-stepping <span class="hlt">fault</span> strands have produced pull-apart basins where Ordovician, Silurian, Devonian, Cretaceous, and Tertiary units are downdropped several hundreds of meters and occur in chaotic orientations. Similar <span class="hlt">fault</span> orientations and kinematics, as well as recent seismicity and close proximity, clearly suggest a structural relationship between deformation at Thebes Gap and tectonism associated with the New Madrid area.« less</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018Tectp.733..209X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018Tectp.733..209X"><span>Strain rate effect on <span class="hlt">fault</span> slip and rupture evolution: Insight from meter-scale rock friction experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Shiqing; Fukuyama, Eiichi; Yamashita, Futoshi; Mizoguchi, Kazuo; Takizawa, Shigeru; Kawakata, Hironori</p> <p>2018-05-01</p> <p>We conduct meter-scale rock friction experiments to study strain rate effect on <span class="hlt">fault</span> slip and rupture evolution. Two rock samples made of Indian metagabbro, with a nominal contact dimension of 1.5 m long and 0.1 m wide, are juxtaposed and loaded in a direct shear configuration to simulate the <span class="hlt">fault</span> motion. A series of experimental tests, under constant loading rates ranging from 0.01 mm/s to 1 mm/s and under a fixed normal stress of 6.7 MPa, are performed to simulate conditions with changing strain rates. Load cells and displacement transducers are utilized to examine the macroscopic <span class="hlt">fault</span> behavior, while high-density arrays of strain gauges close to the <span class="hlt">fault</span> are used to investigate the local <span class="hlt">fault</span> behavior. The observations show that the macroscopic peak strength, strength drop, and the rate of strength drop can increase with increasing loading rate. At the local scale, the observations reveal that slow loading rates favor generation of characteristic ruptures that always nucleate in the form of slow slip at about the same <span class="hlt">location</span>. In contrast, fast loading rates can promote very abrupt rupture nucleation and along-strike scatter of hypocenter <span class="hlt">locations</span>. At a given propagation distance, rupture speed tends to increase with increasing loading rate. We propose that a strain-rate-dependent <span class="hlt">fault</span> fragmentation process can enhance the efficiency of <span class="hlt">fault</span> healing during the stick period, which together with healing time controls the recovery of <span class="hlt">fault</span> strength. In addition, a strain-rate-dependent weakening mechanism can be activated during the slip period, which together with strain energy selects the modes of <span class="hlt">fault</span> slip and rupture propagation. The results help to understand the spectrum of <span class="hlt">fault</span> slip and rock deformation modes in nature, and emphasize the role of heterogeneity in tuning <span class="hlt">fault</span> behavior under different strain rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28676691','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28676691"><span>Near-field <span class="hlt">fault</span> slip of the 2016 Vettore Mw 6.6 earthquake (Central Italy) measured using low-cost GNSS.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wilkinson, Maxwell W; McCaffrey, Ken J W; Jones, Richard R; Roberts, Gerald P; Holdsworth, Robert E; Gregory, Laura C; Walters, Richard J; Wedmore, Luke; Goodall, Huw; Iezzi, Francesco</p> <p>2017-07-04</p> <p>The temporal evolution of slip on surface ruptures during an earthquake is important for assessing <span class="hlt">fault</span> displacement, defining seismic hazard and for predicting ground motion. However, measurements of near-field surface displacement at high temporal resolution are elusive. We present a novel record of near-field co-seismic displacement, measured with 1-second temporal resolution during the 30 th October 2016 M w 6.6 Vettore earthquake (Central Italy), using low-cost Global Navigation Satellite System (GNSS) receivers <span class="hlt">located</span> in the footwall and hangingwall of the Mt. Vettore - Mt. Bove <span class="hlt">fault</span> system, close to new surface ruptures. We observe a clear temporal and spatial link between our near-field record and InSAR, far-field GPS data, regional measurements from the Italian Strong Motion and National Seismic networks, and field measurements of surface ruptures. Comparison of these datasets illustrates that the observed surface ruptures are the propagation of slip from depth on a surface rupturing (i.e. capable) <span class="hlt">fault</span> array, as a direct and immediate response to the 30 th October earthquake. Large near-field displacement ceased within 6-8 seconds of the origin time, implying that shaking induced gravitational processes were not the primary driving mechanism. We demonstrate that low-cost GNSS is an <span class="hlt">accurate</span> monitoring tool when installed as custom-made, short-baseline networks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986JSG.....8..737N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986JSG.....8..737N"><span><span class="hlt">Fault</span> geometries in basement-induced wrench <span class="hlt">faulting</span> under different initial stress states</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Naylor, M. A.; Mandl, G.; Supesteijn, C. H. K.</p> <p></p> <p>Scaled sandbox experiments were used to generate models for relative ages, dip, strike and three-dimensional shape of <span class="hlt">faults</span> in basement-controlled wrench <span class="hlt">faulting</span>. The basic <span class="hlt">fault</span> sequence runs from early en échelon Riedel shears and splay <span class="hlt">faults</span> through 'lower-angle' shears to P shears. The Riedel shears are concave upwards and define a tulip structure in cross-section. In three dimensions, each Riedel shear has a helicoidal form. The sequence of <span class="hlt">faults</span> and three-dimensional geometry are rationalized in terms of the prevailing stress field and Coulomb-Mohr theory of shear failure. The stress state in the sedimentary overburden before wrenching begins has a substantial influence on the <span class="hlt">fault</span> geometries and on the final complexity of the <span class="hlt">fault</span> zone. With the maximum compressive stress (∂ 1) initially parallel to the basement <span class="hlt">fault</span> (transtension), Riedel shears are only slightly en échelon, sub-parallel to the basement <span class="hlt">fault</span>, steeply dipping with a reduced helicoidal aspect. Conversely, with ∂ 1 initially perpendicular to the basement <span class="hlt">fault</span> (transpression), Riedel shears are strongly oblique to the basement <span class="hlt">fault</span> strike, have lower dips and an exaggerated helicoidal form; the final <span class="hlt">fault</span> zone is both wide and complex. We find good agreement between the models and both mechanical theory and natural examples of wrench <span class="hlt">faulting</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JAG...124..148L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JAG...124..148L"><span>Self-constrained inversion of microgravity data along a segment of the Irpinia <span class="hlt">fault</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lo Re, Davide; Florio, Giovanni; Ferranti, Luigi; Ialongo, Simone; Castiello, Gabriella</p> <p>2016-01-01</p> <p>A microgravity survey was completed to precisely <span class="hlt">locate</span> and better characterize the near-surface geometry of a recent <span class="hlt">fault</span> with small throw in a mountainous area in the Southern Apennines (Italy). The site is on a segment of the Irpinia <span class="hlt">fault</span>, which is the source of the M6.9 1980 earthquake. This <span class="hlt">fault</span> cuts a few meter of Mesozoic carbonate bedrock and its younger, mostly Holocene continental deposits cover. The amplitude of the complete Bouguer anomaly along two profiles across the <span class="hlt">fault</span> is about 50 μGal. The data were analyzed and interpreted according to a self-constrained strategy, where some rapid estimation of source parameters was later used as constraint for the inversion. The <span class="hlt">fault</span> has been clearly identified and localized in its horizontal position and depth. Interesting features in the overburden have been identified and their interpretation has allowed us to estimate the <span class="hlt">fault</span> slip-rate, which is consistent with independent geological estimates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeoRL..3521307U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeoRL..3521307U"><span>Heterogeneous rupture on homogenous <span class="hlt">faults</span>: Three-dimensional spontaneous rupture simulations with thermal pressurization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Urata, Yumi; Kuge, Keiko; Kase, Yuko</p> <p>2008-11-01</p> <p>To understand role of fluid on earthquake rupture processes, we investigated effects of thermal pressurization on spatial variation of dynamic rupture by computing spontaneous rupture propagation on a rectangular <span class="hlt">fault</span>. We found thermal pressurization can cause heterogeneity of rupture even on a <span class="hlt">fault</span> of uniform properties. On drained <span class="hlt">faults</span>, tractions drop linearly with increasing slip in the same way everywhere. However, by changing the drained condition to an undrained one, the slip-weakening curves become non-linear and depend on <span class="hlt">locations</span> on <span class="hlt">faults</span> with small shear zone thickness w, and the dynamic frictional stresses vary spatially and temporally. Consequently, the super-shear transition <span class="hlt">fault</span> length decreases for small w, and the final slip distribution can have some peaks regardless of w, especially on undrained <span class="hlt">faults</span>. These effects should be taken into account of determining dynamic rupture parameters and modeling earthquake cycles when the presence of fluid is suggested in the source regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2007/1437/b/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2007/1437/b/"><span>Recurrence Interval and Event Age Data for Type A <span class="hlt">Faults</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dawson, Timothy E.; Weldon, Ray J.; Biasi, Glenn P.</p> <p>2008-01-01</p> <p>This appendix summarizes available recurrence interval, event age, and timing of most recent event data for Type A <span class="hlt">faults</span> considered in the Earthquake Rate Model 2 (ERM 2) and used in the ERM 2 Appendix C analysis as well as Appendix N (time-dependent probabilities). These data have been compiled into an Excel workbook named Appendix B A-<span class="hlt">fault</span> event ages_recurrence_V5.0 (herein referred to as the Appendix B workbook). For convenience, the Appendix B workbook is attached to the end of this document as a series of tables. The tables within the Appendix B workbook include site <span class="hlt">locations</span>, event ages, and recurrence data, and in some cases, the interval of time between earthquakes is also reported. The Appendix B workbook is organized as individual worksheets, with each worksheet named by <span class="hlt">fault</span> and paleoseismic site. Each worksheet contains the site <span class="hlt">location</span> in latitude and longitude, as well as information on event ages, and a summary of recurrence data. Because the data has been compiled from different sources with different presentation styles, descriptions of the contents of each worksheet within the Appendix B spreadsheet are summarized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.S21C0755C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.S21C0755C"><span>Using Earthquake Analysis to Expand the Oklahoma <span class="hlt">Fault</span> Database</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, J. C.; Evans, S. C.; Walter, J. I.</p> <p>2017-12-01</p> <p>The Oklahoma Geological Survey (OGS) is compiling a comprehensive Oklahoma <span class="hlt">Fault</span> Database (OFD), which includes <span class="hlt">faults</span> mapped in OGS publications, university thesis maps, and industry-contributed shapefiles. The OFD includes nearly 20,000 <span class="hlt">fault</span> segments, but the work is far from complete. The OGS plans on incorporating other sources of data into the OFD, such as new <span class="hlt">faults</span> from earthquake sequence analyses, geologic field mapping, active-source seismic surveys, and potential fields modeling. A comparison of Oklahoma seismicity and the OFD reveals that earthquakes in the state appear to nucleate on mostly unmapped or unknown <span class="hlt">faults</span>. Here, we present <span class="hlt">faults</span> derived from earthquake sequence analyses. From 2015 to present, there has been a five-fold increase in realtime seismic stations in Oklahoma, which has greatly expanded and densified the state's seismic network. The current seismic network not only improves our threshold for <span class="hlt">locating</span> weaker earthquakes, but also allows us to better constrain focal plane solutions (FPS) from first motion analyses. Using nodal planes from the FPS, HypoDD relocation, and historic seismic data, we can elucidate these previously unmapped seismogenic <span class="hlt">faults</span>. As the OFD is a primary resource for various scientific investigations, the inclusion of seismogenic <span class="hlt">faults</span> improves further derivative studies, particularly with respect to seismic hazards. Our primal focus is on four areas of interest, which have had M5+ earthquakes in recent Oklahoma history: Pawnee (M5.8), Prague (M5.7), Fairview (M5.1), and Cushing (M5.0). Subsequent areas of interest will include seismically active data-rich areas, such as the central and northcentral parts of the state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70018170','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70018170"><span>Application of ground-penetrating radar to investigation of near-surface <span class="hlt">fault</span> properties in the San Francisco Bay region</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cai, J.; McMechan, G.A.; Fisher, M.A.</p> <p>1996-01-01</p> <p>In many geologic environments, ground-penetrating radar (GPR) provides high-resolution images of near-surface Earth structure. GPR data collection is nondestructive and very economical. The scale of features detected by GPR lies between those imaged by high-resolution seismic reflection surveys and those exposed in trenches and is therefore potentially complementary to traditional techniques for <span class="hlt">fault</span> <span class="hlt">location</span> and mapping. Sixty-two GPR profiles were collected at 12 sites in the San Francisco Bay region. Results show that GPR data correlate with large-scale features in existing trench observations, can be used to <span class="hlt">locate</span> <span class="hlt">faults</span> where they are buried or where their positions are not well known, and can identify previously unknown <span class="hlt">fault</span> segments. The best data acquired were on a profile across the San Andreas <span class="hlt">fault</span>, traversing Pleistocene terrace deposits south of Olema in Marin County; this profile shows a complicated multi-branched <span class="hlt">fault</span> system from the ground surface down to about 40 m, the maximum depth for which data were recorded.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3274107','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3274107"><span>Simplified Interval Observer Scheme: A New Approach for <span class="hlt">Fault</span> Diagnosis in Instruments</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Martínez-Sibaja, Albino; Astorga-Zaragoza, Carlos M.; Alvarado-Lassman, Alejandro; Posada-Gómez, Rubén; Aguila-Rodríguez, Gerardo; Rodríguez-Jarquin, José P.; Adam-Medina, Manuel</p> <p>2011-01-01</p> <p>There are different schemes based on observers to detect and isolate <span class="hlt">faults</span> in dynamic processes. In the case of <span class="hlt">fault</span> diagnosis in instruments (FDI) there are different diagnosis schemes based on the number of observers: the Simplified Observer Scheme (SOS) only requires one observer, uses all the inputs and only one output, detecting <span class="hlt">faults</span> in one detector; the Dedicated Observer Scheme (DOS), which again uses all the inputs and just one output, but this time there is a bank of observers capable of <span class="hlt">locating</span> multiple <span class="hlt">faults</span> in sensors, and the Generalized Observer Scheme (GOS) which involves a reduced bank of observers, where each observer uses all the inputs and m-1 outputs, and allows the localization of unique <span class="hlt">faults</span>. This work proposes a new scheme named Simplified Interval Observer SIOS-FDI, which does not requires the measurement of any input and just with just one output allows the detection of unique <span class="hlt">faults</span> in sensors and because it does not require any input, it simplifies in an important way the diagnosis of <span class="hlt">faults</span> in processes in which it is difficult to measure all the inputs, as in the case of biologic reactors. PMID:22346593</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.T22B0509M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.T22B0509M"><span>Comparative study of two active <span class="hlt">faults</span> in different stages of the earthquake cycle in central Japan -The Atera <span class="hlt">fault</span> (with 1586 Tensho earthquake) and the Nojima <span class="hlt">fault</span> (with 1995 Kobe earthquake)-</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matsuda, T.; Omura, K.; Ikeda, R.</p> <p>2003-12-01</p> <p>National Research Institute for Earth Science and Disaster Prevention (NIED) has been conducting _g<span class="hlt">Fault</span> zone drilling_h. <span class="hlt">Fault</span> zone drilling is especially important in understanding the structure, composition, and physical properties of an active <span class="hlt">fault</span>. In the Chubu district of central Japan, large active <span class="hlt">faults</span> such as the Atotsugawa (with 1858 Hietsu earthquake) and the Atera (with 1586 Tensho earthquake) <span class="hlt">faults</span> exist. After the occurrence of the 1995 Kobe earthquake, it has been widely recognized that direct measurements in <span class="hlt">fault</span> zones by drilling. This time, we describe about the Atera <span class="hlt">fault</span> and the Nojima <span class="hlt">fault</span>. Because, these two <span class="hlt">faults</span> are similar in geological situation (mostly composed of granitic rocks), so it is easy to do comparative study of drilling investigation. The features of the Atera <span class="hlt">fault</span>, which have been dislocated by the 1586 Tensho earthquake, are as follows. Total length is about 70 km. That general trend is NW45 degree with a left-lateral strike slip. Slip rate is estimated as 3-5 m / 1000 years. Seismicity is very low at present and lithologies around the <span class="hlt">fault</span> are basically granitic rocks and rhyolite. Six boreholes have been drilled from the depth of 400 m to 630 m. Four of these boreholes (Hatajiri, Fukuoka, Ueno and Kawaue) are <span class="hlt">located</span> on a line crossing in a direction perpendicular to the Atera <span class="hlt">fault</span>. In the Kawaue well, mostly fractured and alternating granitic rock continued from the surface to the bottom at 630 m. X-ray fluorescence analysis (XRF) is conducted to estimate the amount of major chemical elements using the glass bead method for core samples. The amounts of H20+ are about from 0.5 to 2.5 weight percent. This fractured zone is also characterized by the logging data such as low resistivity, low P-wave velocity, low density and high neutron porosity. The 1995 Kobe (Hyogo-ken Nanbu) earthquake occurred along the NE-SW-trending Rokko-Awaji <span class="hlt">fault</span> system, and the Nojima <span class="hlt">fault</span> appeared on the surface on Awaji Island when this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T43H..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T43H..07W"><span>Effects of Arabia-Eurasia Collision on Strike-slip <span class="hlt">Faults</span> in Central Anatolia?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Whitney, D. L.; Lefebvre, C.; Thomson, S. N.; Idleman, L.; Cosca, M. A.; Kaymakci, N.; Teyssier, C. P.; Umhoefer, P. J.</p> <p>2013-12-01</p> <p>The North and East Anatolian <span class="hlt">faults</span> accommodate much of the tectonic escape of Anatolia in response to Arabia-Eurasia collision and building of the Turkish-Iranian plateau, but these structures formed <10 m.y. ago, at least 25 m.y. after the onset of collision at ~35 Ma. Some of the major strike-slip <span class="hlt">fault</span> zones <span class="hlt">located</span> between the North and East Anatolian <span class="hlt">faults</span> have had long and complex histories of displacement. These <span class="hlt">faults</span> have deformed, and in some cases exhumed, metamorphic massifs <span class="hlt">located</span> between <span class="hlt">fault</span> strands. One example is the Nigde Massif, which was initially exhumed in the Late Cretaceous, then reburied and reheated, along with its overlying sedimentary basin, to a depth of ~10 km at 30 × 5 Ma. Final exhumation and cooling occurred by ~15-17 Ma (massif margin) to ~12 Ma (structurally deepest levels). This depth-temperature-time-deformation history is tracked by a combination of thermobarometric methods, structural and stratigraphic analysis, and geo/thermochronometry (U-Pb zircon, monazite; 40Ar/39Ar hornblende, muscovite, biotite, K-feldspar; zircon and apatite fission-track in metamorphic rocks and basin deposits; and apatite (U-Th)/He). Recent mapping shows the presence of at least two oblique-thrust slices; the structurally higher one accounts for the resetting of detrital apatite fission track and AHe ages in the basin rocks as well as metamorphic apatite near the margin of the massif. The structurally deeper one cuts through the metamorphic basement and explains why mineral lineations and metamorphic assemblages are different along the eastern margin relative to those in the core of the massif. Although the timing of displacement has not been dated directly, low-T thermochronology age and modeling results document a perturbation at ~30 Ma, consistent with the idea that the Ecemis <span class="hlt">Fault</span> of the Central Anatolian <span class="hlt">Fault</span> Zone, and probably other pre-existing strike-slip <span class="hlt">faults</span> in central Anatolia, experienced Late Eocene-Oligocene displacement in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T23F0689M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T23F0689M"><span>Stress and Strain Rates from <span class="hlt">Faults</span> Reconstructed by Earthquakes Relocalization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morra, G.; Chiaraluce, L.; Di Stefano, R.; Michele, M.; Cambiotti, G.; Yuen, D. A.; Brunsvik, B.</p> <p>2017-12-01</p> <p>Recurrence of main earthquakes on the same <span class="hlt">fault</span> depends on kinematic setting, hosting lithologies and <span class="hlt">fault</span> geometry and population. Northern and central Italy transitioned from convergence to post-orogenic extension. This has produced a unique and very complex tectonic setting characterized by superimposed normal <span class="hlt">faults</span>, crossing different geologic domains, that allows to investigate a variety of seismic manifestations. In the past twenty years three seismic sequences (1997 Colfiorito, 2009 L'Aquila and 2016-17 Amatrice-Norcia-Visso) activated a 150km long normal <span class="hlt">fault</span> system <span class="hlt">located</span> between the central and northern apennines and allowing the recordings of thousands of seismic events. Both the 1997 and the 2009 main shocks were preceded by a series of small pre-shocks occurring in proximity to the future largest events. It has been proposed and modelled that the seismicity pattern of the two foreshocks sequences was caused by active dilatancy phenomenon, due to fluid flow in the source area. Seismic activity has continued intensively until three events with 6.0</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoJI.204.1503H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoJI.204.1503H"><span><span class="hlt">Fault</span> zone reverberations from cross-correlations of earthquake waveforms and seismic noise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hillers, Gregor; Campillo, Michel</p> <p>2016-03-01</p> <p>Seismic wavefields interact with low-velocity <span class="hlt">fault</span> damage zones. Waveforms of ballistic <span class="hlt">fault</span> zone head waves, trapped waves, reflected waves and signatures of trapped noise can provide important information on structural and mechanical <span class="hlt">fault</span> zone properties. Here we extend the class of observable <span class="hlt">fault</span> zone waves and reconstruct in-<span class="hlt">fault</span> reverberations or multiples in a strike-slip <span class="hlt">faulting</span> environment. Manifestations of the reverberations are significant, consistent wave fronts in the coda of cross-correlation functions that are obtained from scattered earthquake waveforms and seismic noise recorded by a linear <span class="hlt">fault</span> zone array. The physical reconstruction of Green's functions is evident from the high similarity between the signals obtained from the two different scattered wavefields. Modal partitioning of the reverberation wavefield can be tuned using different data normalization techniques. The results imply that <span class="hlt">fault</span> zones create their own ambiance, and that the here reconstructed reverberations are a key seismic signature of wear zones. Using synthetic waveform modelling we show that reverberations can be used for the imaging of structural units by estimating the <span class="hlt">location</span>, extend and magnitude of lateral velocity contrasts. The robust reconstruction of the reverberations from noise records suggests the possibility to resolve the response of the damage zone material to various external and internal loading mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2018JSG...111...27B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2018JSG...111...27B"><span>Near-surface clay authigenesis in exhumed <span class="hlt">fault</span> rock of the Alpine <span class="hlt">Fault</span> Zone (New Zealand); O-H-Ar isotopic, XRD and chemical analysis of illite and chlorite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Boles, Austin; Mulch, Andreas; van der Pluijm, Ben</p> <p>2018-06-01</p> <p>Exhumed <span class="hlt">fault</span> rock of the central Alpine <span class="hlt">Fault</span> Zone (South Island, New Zealand) shows extensive clay mineralization, and it has been the focus of recent research that aims to describe the evolution and frictional behavior of the <span class="hlt">fault</span>. Using Quantitative X-ray powder diffraction, 40Ar/39Ar geochronology, hydrogen isotope (δD) geochemistry, and electron microbeam analysis, we constrain the thermal and fluid conditions of deformation that produced two predominant clay phases ubiquitous to the exposed <span class="hlt">fault</span> damage zone, illite and chlorite. Illite polytype analysis indicates that most end-member illite and chlorite material formed in equilibrium with meteoric fluid (δD = -55 to -75‰), but two <span class="hlt">locations</span> preserve a metamorphic origin of chlorite (δD = -36 to -45‰). Chlorite chemical geothermometry constrains crystal growth to T = 210-296 °C. Isotopic analysis also constrains illite growth to T < 100 °C, consistent with the mineralogy, with Ar ages <0.5 Ma. High geothermal gradients in the study area promoted widespread, near-surface mineralization, and limited the window of clay authigenesis in the Alpine <span class="hlt">Fault</span> Zone to <5 km for chlorite and <2 km for illite. This implies a significant contrast between <span class="hlt">fault</span> rock exposed at the surface and that at depth, and informs discussions about <span class="hlt">fault</span> strength, clays and frictional behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.er.usgs.gov/publication/70030544','USGSPUBS'); return false;" href="https://pubs.er.usgs.gov/publication/70030544"><span>Monitoring microearthquakes with the San Andreas <span class="hlt">fault</span> observatory at depth</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Oye, V.; Ellsworth, W.L.</p> <p>2007-01-01</p> <p>In 2005, the San Andreas <span class="hlt">Fault</span> Observatory at Depth (SAFOD) was drilled through the San Andreas <span class="hlt">Fault</span> zone at a depth of about 3.1 km. The borehole has subsequently been instrumented with high-frequency geophones in order to better constrain <span class="hlt">locations</span> and source processes of nearby microearthquakes that will be targeted in the upcoming phase of SAFOD. The microseismic monitoring software MIMO, developed by NORSAR, has been installed at SAFOD to provide near-real time <span class="hlt">locations</span> and magnitude estimates using the high sampling rate (4000 Hz) waveform data. To improve the detection and <span class="hlt">location</span> accuracy, we incorporate data from the nearby, shallow borehole (???250 m) seismometers of the High Resolution Seismic Network (HRSN). The event association algorithm of the MIMO software incorporates HRSN detections provided by the USGS real time earthworm software. The concept of the new event association is based on the generalized beam forming, primarily used in array seismology. The method requires the pre-computation of theoretical travel times in a 3D grid of potential microearthquake <span class="hlt">locations</span> to the seismometers of the current station network. By minimizing the differences between theoretical and observed detection times an event is associated and the <span class="hlt">location</span> accuracy is significantly improved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MeScR..12..111H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MeScR..12..111H"><span>Staged-<span class="hlt">Fault</span> Testing of Distance Protection Relay Settings</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Havelka, J.; Malarić, R.; Frlan, K.</p> <p>2012-01-01</p> <p>In order to analyze the operation of the protection system during induced <span class="hlt">fault</span> testing in the Croatian power system, a simulation using the CAPE software has been performed. The CAPE software (Computer-Aided Protection Engineering) is expert software intended primarily for relay protection engineers, which calculates current and voltage values during <span class="hlt">faults</span> in the power system, so that relay protection devices can be properly set up. Once the accuracy of the simulation model had been confirmed, a series of simulations were performed in order to obtain the optimal <span class="hlt">fault</span> <span class="hlt">location</span> to test the protection system. The simulation results were used to specify the test sequence definitions for the end-to-end relay testing using advanced testing equipment with GPS synchronization for secondary injection in protection schemes based on communication. The objective of the end-to-end testing was to perform field validation of the protection settings, including verification of the circuit breaker operation, telecommunication channel time and the effectiveness of the relay algorithms. Once the end-to-end secondary injection testing had been completed, the induced <span class="hlt">fault</span> testing was performed with three-end lines loaded and in service. This paper describes and analyses the test procedure, consisting of CAPE simulations, end-to-end test with advanced secondary equipment and staged-<span class="hlt">fault</span> test of a three-end power line in the Croatian transmission system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/2000/ofr-00-0018/','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/2000/ofr-00-0018/"><span>Map and database of Quaternary <span class="hlt">faults</span> in Venezuela and its offshore regions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Audemard, F.A.; Machette, M.N.; Cox, J.W.; Dart, R.L.; Haller, K.M.</p> <p>2000-01-01</p> <p>As part of the International Lithosphere Program’s “World Map of Major Active <span class="hlt">Faults</span>,” the U.S. Geological Survey is assisting in the compilation of a series of digital maps of Quaternary <span class="hlt">faults</span> and folds in Western Hemisphere countries. The maps show the <span class="hlt">locations</span>, ages, and activity rates of major earthquake-related features such as <span class="hlt">faults</span> and <span class="hlt">fault</span>-related folds. They are accompanied by databases that describe these features and document current information on their activity in the Quaternary. The project is a key part of the Global Seismic Hazards Assessment Program (ILP Project II-0) for the International Decade for Natural Hazard Disaster Reduction.The project is sponsored by the International Lithosphere Program and funded by the USGS’s National Earthquake Hazards Reduction Program. The primary elements of the project are general supervision and interpretation of geologic/tectonic information, data compilation and entry for <span class="hlt">fault</span> catalog, database design and management, and digitization and manipulation of data in †ARCINFO. For the compilation of data, we engaged experts in Quaternary <span class="hlt">faulting</span>, neotectonics, paleoseismology, and seismology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997P%26SS...45.1069N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997P%26SS...45.1069N"><span>Tectonic lineations and frictional <span class="hlt">faulting</span> on a relatively simple body (Ariel)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nyffenegger, Paul; Davis, Dan M.; Consolmagno, Guy J.</p> <p>1997-09-01</p> <p>Anderson's model of <span class="hlt">faulting</span> and the Mohr-Coulomb failure criterion can predict the orientations of <span class="hlt">faults</span> generated in laboratory triaxial compression experiments, but do a much poorer job of explaining the orientations of outcrop- and map-scale <span class="hlt">faults</span> on Earth. This failure may be due to the structural complexity of the Earth's lithosphere, the failure of laboratory experiments to predict <span class="hlt">accurately</span> the strength of natural <span class="hlt">faults</span>, or some fundamental flaw in the model. A simpler environment, such as the lithosphere of an icy satellite, allows us to test whether this model can succeed in less complex settings. A mathematical method is developed to analyze patterns in fracture orientations that can be applied to fractures in the lithospheres of icy satellites. In a initial test of the method, more than 300 lineations on Uranus' satellite Ariel are examined. A nonrandom pattern of lineations is looked for, and the source of the stresses that caused those features and the strength of the material in which they occur are constrained. It is impossible to observe directly the slip on these fractures. However, their orientations are clearly nonrandom and appear to be consistent with Andersonian strike-slip <span class="hlt">faulting</span> in a relatively weak frictional lithosphere during one or more episodes of tidal flexing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T21A2519Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T21A2519Z"><span>Active <span class="hlt">fault</span> systems of the Kivu rift and Virunga volcanic province, and implications for geohazards</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zal, H. J.; Ebinger, C. J.; Wood, D. J.; Scholz, C. A.; d'Oreye, N.; Carn, S. A.; Rutagarama, U.</p> <p>2013-12-01</p> <p>H Zal, C Ebinger, D. Wood, C. Scholz, N. d'Oreye, S. Carn, U. Rutagarama The weakly magmatic Western rift system, East Africa, is marked by <span class="hlt">fault</span>-bounded basins filled by freshwater lakes that record tectonic and climatic signals. One of the smallest of the African Great Lakes, Lake Kivu, represents a unique geohazard owing to the warm, saline bottom waters that are saturated in methane, as well as two of the most active volcanoes in Africa that effectively dam the northern end of the lake. Yet, the dynamics of the basin system and the role of magmatism were only loosely constrained prior to new field and laboratory studies in Rwanda. In this work, we curated, merged, and analyzed historical and digital data sets, including spectral analyses of merged Shuttle Radar Topography Mission topography and high resolution CHIRP bathymetry calibrated by previously mapped <span class="hlt">fault</span> <span class="hlt">locations</span> along the margins and beneath the lake. We quantitatively compare these <span class="hlt">fault</span> maps with the time-space distribution of earthquakes <span class="hlt">located</span> using data from a temporary array along the northern sector of Lake Kivu, as well as space-based geodetic data. During 2012, seismicity rates were highest beneath Nyiragongo volcano, where a range of low frequency (1-3 s peak frequency) to tectonic earthquakes were <span class="hlt">located</span>. Swarms of low-frequency earthquakes correspond to periods of elevated gas emissions, as detected by Ozone Monitoring Instrument (OMI). Earthquake swarms also occur beneath Karisimbi and Nyamuragira volcanoes. A migrating swarm of earthquakes in May 2012 suggests a sill intrusion at the DR Congo-Rwanda border. We delineate two <span class="hlt">fault</span> sets: SW-NE, and sub-N-S. Excluding the volcano-tectonic earthquakes, most of the earthquakes are <span class="hlt">located</span> along subsurface projections of steep border <span class="hlt">faults</span>, and intrabasinal <span class="hlt">faults</span> calibrated by seismic reflection data. Small magnitude earthquakes also occur beneath the uplifted rift flanks. Time-space variations in seismicity patterns provide a baseline</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017AGUFM.T41C0648L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017AGUFM.T41C0648L"><span><span class="hlt">Fault</span> zone property near Xinfengjiang Reservoir using dense, across-<span class="hlt">fault</span> seismic array</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, M. H. B.; Yang, H.; Sun, X.</p> <p>2017-12-01</p> <p>Properties of <span class="hlt">fault</span> zones are important to the understanding of earthquake process. Around the <span class="hlt">fault</span> zone is a damaged zone which is characterised by a lower seismic velocity. This is detectable as a low velocity zone and measure some physical property of the <span class="hlt">fault</span> zone, which is otherwise difficult sample directly. A dense, across-<span class="hlt">fault</span> array of short period seismometer is deployed on an inactive <span class="hlt">fault</span> near Xinfengjiang Reservoir. Local events were manually picked. By computing the synthetic arrival time, we were able to constrain the parameters of the <span class="hlt">fault</span> zone Preliminary result shows that the <span class="hlt">fault</span> zone is around 350 m wide with a P and S velocity increase of around 10%. The <span class="hlt">fault</span> is geologically inferred, and this result suggested that it may be a geological layer. The other possibility is that the higher velocity is caused by a combination of <span class="hlt">fault</span> zone healing and fluid intrusion. Whilst the result was not able to tell us the nature of the <span class="hlt">fault</span>, it demonstrated that this method is able to derive properties from a <span class="hlt">fault</span> zone.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <div class="footer-extlink text-muted" style="margin-bottom:1rem; text-align:center;">Some links on this page may take you to non-federal websites. 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