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1

Paleoseismic study of the Cathedral Rapids fault in the northern Alaska Range near Tok, Alaska  

NASA Astrophysics Data System (ADS)

The Cathedral Rapids fault extends ~40 km between the Tok and Robertson River valleys and is the easternmost fault in a series of active south-dipping imbricate thrust faults which bound the northern flank of the Alaska Range. Collectively, these faults accommodate a component of convergence transferred north of the Denali fault and related to the westward (counterclockwise) rotation of the Wrangell Block driven by relative Pacific/North American plate motion along the eastern Aleutian subduction zone and Fairweather fault system. To the west, the system has been defined as the Northern Foothills Fold and Thrust Belt (NFFTB), a 50-km-wide zone of east-west trending thrust faults that displace Quaternary deposits and have accommodated ~3 mm/yr of shortening since latest Pliocene time (Bemis, 2004). Over the last several years, the eastward extension of the NFFTB between Delta Junction and the Canadian border has been studied by the Alaska Division of Geological & Geophysical Surveys to better characterize faults that may affect engineering design of the proposed Alaska-Canada natural gas pipeline and other infrastructure. We summarize herein reconnaissance field observations along the western part of the Cathedral Rapids fault. The western part of the Cathedral Rapids fault extends 21 km from Sheep Creek to Moon Lake and is characterized by three roughly parallel sinuous traces that offset glacial deposits of the Illinoian to early Wisconsinan Delta glaciations and the late Wisconsinan Donnelly glaciation, as well as, Holocene alluvial deposits. The northern trace of the fault is characterized by an oversteepened, beveled, ~2.5-m-high scarp that obliquely cuts a Holocene alluvial fan and projects into the rangefront. Previous paleoseismic studies along the eastern part of the Cathedral Rapids fault and Dot “T” Johnson fault indicate multiple latest Pleistocene and Holocene earthquakes associated with anticlinal folding and thrust faulting (Carver et al., 2010). Combined with this previous work, our paleoseismic assessment of the western Cathedral Rapids fault, including trenching in fall 2010, may contribute to increasing the understanding of the style and timing of deformation for faults bounding the northern flank of the Alaska Range. These data may also provide insight into the eastern extent of the NFFTB and its role in accommodating regional shortening.

Koehler, R. D.; Farrell, R.; Carver, G. A.

2010-12-01

2

Denali Fault: Black Rapids Glacier  

USGS Multimedia Gallery

View eastward along Black Rapids Galcier. The Denali fault follows the trace of the glacier. These very large rockslides went a mile across the glacier on the right side. Investigations of the headwall of the middle landslide indicate a volume at least as large as that which fell, has dropped a mete...

2008-12-15

3

Anisotropy of magnetic susceptibility (AMS) analysis of basalt dikes at Cathedral Cliffs, WY: implications for Heart Mountain faulting  

Microsoft Academic Search

Mafic dikes pervade the upper plate of the Heart Mountain Detachment (HMD), yet the dike concentration in the lower plate is sparse. Previous workers interpreted that these dikes were emplaced either coeval with or subsequent to the emplacement of the upper plate. The magnetic fabrics of 32 mafic dikes at Cathedral Cliffs were analyzed using low-field anisotropy of magnetic susceptibility

Josh Defrates; David H. Malone; John P. Craddock

2006-01-01

4

Anisotropy of magnetic susceptibility (AMS) analysis of basalt dikes at Cathedral Cliffs, WY: implications for Heart Mountain faulting  

NASA Astrophysics Data System (ADS)

Mafic dikes pervade the upper plate of the Heart Mountain Detachment (HMD), yet the dike concentration in the lower plate is sparse. Previous workers interpreted that these dikes were emplaced either coeval with or subsequent to the emplacement of the upper plate. The magnetic fabrics of 32 mafic dikes at Cathedral Cliffs were analyzed using low-field anisotropy of magnetic susceptibility (AMS) as a proxy for flow. These dikes intrude Ordovician-Mississippian carbonate and overlying Eocene volcanic rocks and are truncated along the nearly horizontal HMD. The dikes trend between N10°W and N20°E, are all steeply dipping, and range in width between 0.5 and 3 m. Flow directions for the dikes were determined by the bearing and plunge of the Kmax (maximum principal susceptibility) axes relative to the dike orientation. About 66% of the dikes sampled show typical dike AMS patterns with Kmax and Kint in the plane of the dike and Kmin normal to the dike plane. About 66% of the dikes sampled have Kmax inclinations >45° and thus were emplaced upward; 16% of the dikes have Kmax inclinations of <10° and thus were emplaced laterally. The remaining dikes have intermediate Kmax inclinations. With numerous dikes showing vertical to sub-vertical emplacement directions and with no magmatic source immediately below the detachment the dikes must predate emplacement of the upper plate. Therefore, upper plate dilation by dike intrusion could not be a driving force for protracted extension. Our date is consistent with a single catastrophic emplacement event, and inconsistent with an extensional allochthon model of incremental emplacement over long intervals of time.

DeFrates, Josh; Malone, David H.; Craddock, John P.

2006-01-01

5

St. Paul's Cathedral  

NSDL National Science Digital Library

Perhaps one of the finest neo-Classical cathedrals in the world, the current St. Paul's cathedral is an example of the outstanding architecture of Christopher Wren, and a testimony to his dogged persistence and passion for his life's work. In keeping with the attention to detail that is indicative of Mr. Wren's work, the St. Paul's Web site has detailed information on visiting the cathedral, the various musical performances that it hosts, and an interactive timeline detailing the history of St. Paul's that extends back to the year 604. Along with this information, the site also tells visitors about upcoming events at the cathedral, along with an extensive online gift shop that offers a diverse set of St. Paul's related material for purchase.

6

Amiens and Its Cathedral.  

ERIC Educational Resources Information Center

Introduces a place of mathematics using a town called Amiens and its Cathedral whose overall floor plan was based on the Greek cross using proportions matching that of the ideal human body, the figures in the shape of an octagram or star octagon, and the symbols in the design. (ASK)

Brinkworth, Peter; Scott, Paul

1997-01-01

7

Earthquake Resistant Cathedral in Chile  

USGS Multimedia Gallery

A cathedral in the central square of Chillán, Chile replaces the ancient cathedral that collapsed during the strong earthquake of 1939. This modern structure was constructed with earthquake resistance as the primary consideration. The only damage caused by the M 8.8 earthquake on Feb. 27, 2010 was b...

2010-03-30

8

An example of complex fault geometries in a young, rapidly deforming transform fault system: The Maacama Fault in northern California  

NASA Astrophysics Data System (ADS)

The Maacama Fault Zone (MFZ) in northern California is a young transform system that developed behind the northward migrating Mendocino Triple Junction, and comprises a complex set of active, linked fault strands that form a series of pull-apart basins within the rapidly slipping (~13.9 mm/yr) right-lateral fault system. Surface fault traces within the MFZ are defined by geomorphic features, shallow resistivity profiles, and previously published surface creep and paleoseismic trenching studies. The surface traces of these faults outline classic pull-apart rhomohedrons, with all of the bounding faults inferred to be kinematically linked and currenty active. This activity is supported not only by paleoseismic and surface creep studies, which have tended to focus on the single main strand of the Maacama Fault, but also by the location of tabular seismogenic zones that project from the subsurface into several of the mapped surface fault traces. For each of the 3 mapped pull-apart basins, at least two of the interpreted bounding faults can be shown to be currently active, requiring near-synchronous activity on all of the kinematically linked faults. Historically, active displacement across the MFZ has been assigned to only one relatively well-studied main strand of the fault zone, which slips at ~6.5 mm/yr, resulting in an apparent slip deficit of ~7.4 mm/yr. However, the newly studied adjacent faults in this complex system could accommodate as much or more slip than the historically defined main fault trace, thus resulting in a possibly broader zone of seismic hazard, but less risk of major earthquakes on the main trace. Timing of pull-apart basin initiations is not well constrained, with data permitting either the interpretation that basins formed due to oblique subduction and are currently being reactivated by similar stresses, or that they are newly formed and rapidly evolving. Limited data even allows that the largest pull-apart system may be a reactivated pre-existing structure, while the remaining two pull-aparts are newly formed. At several locations, the MFZ clearly reactivates pre-existing Franciscan subduction-related structures. Evidence of this includes the correlation of surface projections of seismogenic zones with outcrops of subduction related fault zones, and also best-fit planes through seismicity that have the same attitude as the pre-existing reverse faults that are seen in the Franciscan accretionary prism. Outcrops along these pre-existing fault zones have been analyzed by thin-section and XRD analysis, and include abundant mixed-layer clays, serpentine and chrysotile, and silica-carbonate. While each of these sheared deposits are evidence of a fault zone, the abundant clay in particular may be responsible for facilitating fault creep, such as the ~6.5 mm/yr seen on the main strand of the MFZ, and as has been suggested in the same formation at the SAFOD site in central California. The complexity of the MFZ is interpreted to result at least partially from the fact that it deforms heterogeneous Fransican mélange lithologies, which offer a closely spaced set of weak pre-existing fault planes that accommodate rapid displacement along the young San Andreas transform boundary.

Schroeder, R. D.; Brady, R. J.

2009-12-01

9

Rapid Determination of Near-Fault Earthquake Deformation Using LIDAR  

NASA Astrophysics Data System (ADS)

The 2005 airborne lidar survey of the southern San Andreas, San Jacinto and Banning faults (the "B4 Survey") has delivered a high-resolution digital elevation model (DEM) of 1100 km of the most seismically active fault systems in southern California for the express purpose of providing a baseline for post-earthquake slip determination. We used this survey as a testbed to experiment with processing algorithms for rapid estimation of near-fault ground deformation. One algorithm uses simultaneous cross correlation of both topography and backscatter intensity from pre-earthquake and simulated post-earthquake LIDAR datasets. We show robust recovery of the direction and magnitude of an applied synthetic slip of 5 m in the horizontal and 0.5 m in the vertical within the test area, with excellent discrimination between areas with and without applied slip. Another algorithm relies on an evolutionary programming approach, which is more robust in the presence of multiple minima of the solution manifold, but requires substantially more processing power. Our results indicate that one should be able to recover slip to accuracies of better than 20 cm in the horizontal and 1 cm in the vertical, at a spatial resolution of ?15 m for lidar datasets with sample densities as low as 0.5 points/m2.

Borsa, A. A.; Minster, J. H.

2011-12-01

10

Rapid Determination of Near-Fault Earthquake Deformation using LIDAR  

NASA Astrophysics Data System (ADS)

The 2005 airborne lidar swath mapping (ALSM) survey of the southern San Andreas, San Jacinto and Banning faults (the “B4 survey”) delivered a high-resolution digital elevation model of 1100 km of the most seismically active fault systems in southern California for the express purpose of providing a baseline for post-earthquake slip determination. We used the B4 survey as a testbed to develop a processing algorithm that rapidly estimates near-fault coseismic ground deformation using simultaneous cross correlation of topography and backscatter intensity from pre/post-earthquake LIDAR datasets. We show robust recovery of the direction and magnitude of an applied synthetic slip of 5 m in the horizontal and 0.5 m in the vertical, with excellent discrimination between areas with and without applied slip. Our results indicate that we should be able to accurately recover horizontal slip ?0.5 m and vertical slip ?3 cm. We also used this algorithm to investigate misfit between overlapping B4 survey swaths in both the horizontal and vertical; our previous work in this area focused only on the vertical component of error. Significant calibration errors in geolocation resulted in across-swath elevation errors throughout the B4 survey of equal or greater magnitude than the expected vertical GPS error. This suggests that further research in calibration methods would have at least as much impact on survey accuracy as improving GPS trajectories and could greatly improve the recovery of the small vertical coseismic displacements expected in a strike-slip regime such as the San Andreas.

Borsa, A. A.; Minster, J. H.

2009-12-01

11

Rapid detection of faults for safety critical aircraft operation  

Microsoft Academic Search

Fault diagnosis typically assumes a sufficiently large fault signature and enough time for a reliable decision to be reached. However, for a class of safety critical faults on commercial aircraft engines, prompt detection is paramount within a millisecond range to allow accommodation to avert undesired engine behavior. At the same time, false positives must be avoided to prevent inappropriate control

Kai Goebel; Neil Eklund; Brent Brunell

2004-01-01

12

Cathedral house & crocker fence, Taylor Street east and north ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Cathedral house & crocker fence, Taylor Street east and north elevations, perspective view from the northeast - Grace Cathedral, George William Gibbs Memorial Hall, 1051 Taylor Street, San Francisco, San Francisco County, CA

13

Rapid recovery from transient faults in the fault-tolerant processor with fault-tolerant shared memory  

NASA Technical Reports Server (NTRS)

The Draper fault-tolerant processor with fault-tolerant shared memory (FTP/FTSM), which is designed to allow application tasks to continue execution during the memory alignment process, is described. Processor performance is not affected by memory alignment. In addition, the FTP/FTSM incorporates a hardware scrubber device to perform the memory alignment quickly during unused memory access cycles. The FTP/FTSM architecture is described, followed by an estimate of the time required for channel reintegration.

Harper, Richard E.; Butler, Bryan P.

1990-01-01

14

Fault structures in rapidly quenched Ni-Mo binary alloys  

NASA Technical Reports Server (NTRS)

Fault structures in two Ni-Mo alloy ribbons (Ni-28 at. pct Mo and Ni-35 at. pct Mo) cast by a free jet chill block melt spinning process were studied. Thin foils for TEM studies were made by electrochemical thinning using an alcohol/butyl cellosolve/perchloric acid mixture in a twin jet electropolishing device. The samples displayed typical grains containing linear faulted regions on the wheelside of the two alloy ribbons. However, an anomalous diffraction behavior was observed upon continuous tilting of the sample: the network of diffraction spots from a single grain appeared to expand or contract and rotate. This anomalous diffraction behavior was explained by assuming extended spike formation at reciprocal lattice points, resulting in a network of continuous rel rods. The validity of the model was confirmed by observations of a cross section of the reciprocal lattice parallel to the rel rods.

Jayaraman, N.; Tewari, S. N.

1986-01-01

15

The Role of Advection on Fault Zone Temperature after an Earthquake: Implications for Rapid Response Drilling  

NASA Astrophysics Data System (ADS)

The lack of near-fault thermal anomalies as predicted for frictional heat generation has been one of the primary observations suggesting that many large faults slip at very low shear stresses. In addition to the lack of a heat flow anomaly near the San Andreas Fault, scientific boreholes that intersect fault zones within months to years after major earthquakes (Nojima and Chelungpu) have failed to observe the predicted temperature anomalies. Understanding how a thermal signature from frictional heating may be perturbed by advection is critical for interpreting these thermal observations in terms of fault strength, and also in designing a potential rapid response borehole that would cross a fault soon after a large earthquake. Although previous studies have illustrated that for the San Andreas Fault, the long term effects of topographically-driven groundwater flow are unlikely to obscure a heat flow anomaly, the extent to which transient groundwater flow, driven by earthquake processes, affects the thermal signature across seismogenic faults is unresolved. Here, using 2-D models of coupled fluid flow and heat transport, we evaluate whether rapid heating and pressurization of fluids during an earthquake can drive advective flow that modifies the temperature signature from frictional heating. For a wide range of assumed permeability scenarios, we simulate heating and pressurization for an earthquake with 5 m of slip on a thrust fault (similar to the 1999 Chi-Chi earthquake on the Chelungpu fault in Taiwan or the 2008 Sichuan earthquake in China, both with Mw > 7), and evaluate the resulting effects on fluid flow and temperature. Our results show that very high permeabilities (>10-14 m2) are needed before there are significant differences from the conduction-dominated results. However, even in simulations that include high permeability in the fault or country rock (up to 10- 13 m2) advective flow only has a small effect on the temperature anomaly across the fault (<5% difference from the conductive solution after 2 years). Our results suggest that transient advective flow from thermal pressurization is unlikely to obscure a thermal anomaly from frictional heating, and that a frictional heat signature should still be detectable at drillable depths (~1 to 4 km) within a rapid response borehole 1 to 2 years after a large earthquake.

Fulton, P. M.; Saffer, D. M.; Brodsky, E. E.

2008-12-01

16

Rapid Assessment of Earthquakes with Radar and Optical Geodetic Imaging and Finite Fault Models (Invited)  

NASA Astrophysics Data System (ADS)

Earthquake responders need to know where the earthquake has caused damage and what is the likely intensity of damage. The earliest information comes from global and regional seismic networks, which provide the magnitude and locations of the main earthquake hypocenter and moment tensor centroid and also the locations of aftershocks. Location accuracy depends on the availability of seismic data close to the earthquake source. Finite fault models of the earthquake slip can be derived from analysis of seismic waveforms alone, but the results can have large errors in the location of the fault ruptures and spatial distribution of slip, which are critical for estimating the distribution of shaking and damage. Geodetic measurements of ground displacements with GPS, LiDAR, or radar and optical imagery provide key spatial constraints on the location of the fault ruptures and distribution of slip. Here we describe the analysis of interferometric synthetic aperture radar (InSAR) and sub-pixel correlation (or pixel offset tracking) of radar and optical imagery to measure ground coseismic displacements for recent large earthquakes, and lessons learned for rapid assessment of future events. These geodetic imaging techniques have been applied to the 2010 Leogane, Haiti; 2010 Maule, Chile; 2010 Baja California, Mexico; 2008 Wenchuan, China; 2007 Tocopilla, Chile; 2007 Pisco, Peru; 2005 Kashmir; and 2003 Bam, Iran earthquakes, using data from ESA Envisat ASAR, JAXA ALOS PALSAR, NASA Terra ASTER and CNES SPOT5 satellite instruments and the NASA/JPL UAVSAR airborne system. For these events, the geodetic data provided unique information on the location of the fault or faults that ruptured and the distribution of slip that was not available from the seismic data and allowed the creation of accurate finite fault source models. In many of these cases, the fault ruptures were on previously unknown faults or faults not believed to be at high risk of earthquakes, so the area and degree of damage was a surprise. The satellite or airborne imagery was not available in the first days after these earthquakes, and hand-crafted analysis added more time after data delivery, so source assessment products were not useful for the initial rescue operations, but they were useful for guiding field mapping and early recovery planning. Future rapid assessment of earthquakes could be speeded by automated analysis and more prompt data accessibility to provide products in time to benefit rescue operations.

Fielding, E. J.; Sladen, A.; Simons, M.; Rosen, P. A.; Yun, S.; Li, Z.; Avouac, J.; Leprince, S.

2010-12-01

17

DISTANT VIEW OF ST. FRANCIS DE SALES CATHEDRAL, LOOKING NORTH ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DISTANT VIEW OF ST. FRANCIS DE SALES CATHEDRAL, LOOKING NORTH ALONG MARTIN LUTHER KING JR. WAY FROM 14TH STREET - St. Francis de Sales Church, 2100 Martin Luther King, Jr. Way, Oakland, Alameda County, CA

18

Materials Physics of Faults in Rapid Shear and Consequences for Earthquake Dynamics (Louis Néel Medal Lecture)  

NASA Astrophysics Data System (ADS)

Field observations of maturely slipped faults show that despite a generally broad zone of damage by cracking and granulation, large shear deformation, and therefore heat generation, in individual earthquakes takes place with extreme localization to a zone of order 1 mm or less width within a finely granulated fault core. Relevant fault weakening processes during large crustal events are therefore likely to be thermally influenced, although a constraint to be met, from scarcity of pseudotachylite, is that melting within fault zones seems relatively rare, at least in the up per crust. Further, given the porosit y of damage zones, it seems reasonable to assume in-situ water presence. The lecture reviews current understanding of the materials physics underlying rapid shear of such fault zones, addressing questions like: Why is there severe localization? What are the dynamic relations between shear stress sustained by the fault and its slip history? How do those relations, taken to provide the boundary conditions on a rupturing interface between elastic regions of the earth, control key features of the dynamics of earthquakes? Primary dynamic weakening mechanisms, expected active in at least the early phases of nearly all crustal events, are flash heating at highly stressed frictional micro-contacts and thermal pressurization of native fault-zone pore fluid, the latter with a net effect that depends on interactions with dilatancy. Other weakening processes may also become active at large enough T rise, still prior to bulk melting, including endothermic decomposition reactions releasing a CO2 or H2O fluid phase under conditions that the fluid and solid products would, at the same p and T , occupy more volume than the parent rock, so that the pore fluid is forced to undergo severe pressure increase. The endothermic nature of the reactions buffers against melting because frictional work is absorbed into enthalpy increase of the reactants. There may also be a contribution to the weakening linked to the typically nanoscale range of the solid product phases. The results, applied to modeling of spontaneous slip ruptures, show how faults can be statically strong yet dynamically weak, and operate under low overall driving stress, in a manner that generates negligible heat and meets major seismic constraints on slip, stress drop, and self-healing rupture mode. They also shed light on how fault segments that normally shear stably, so as to not nucleate earthquakes, can nevertheless take part in major events when a high-slip rupture impinges from a bordering segment. The studies reviewed have been done collaboratively with, or draw on the separate insights of, N. Brantut, M. Cocco, E. Dunham, D. Garagash, D. Goldsby, N. Lapusta, H. Noda, J. Platt, A. Rempel, J. Rudnicki, P. Segall, T. Shimamoto, J. Sulem, T. Tullis and I. Vardoulakis.

Rice, J. R.

2012-04-01

19

Has the Nojima fault healed rapidly? Results from seismogenic zone drilling and monitoring at the Nojima fault, Japan  

Microsoft Academic Search

After the 1995 Kobe earthquake (M=7.2),Geological Survey of Japan (GSJ), National Research Institute of Earthquake Science and Disaster Prevention (NIED), and University group drille boreholes along the Nojima fault which appeared as surface break after the earthquake. The boreholes at Hirabayashi, where the maximum slip of 2 m was observed, drilled by GSJ and NIED penetrated fault core of the

H. Ito; E. Roeloffs; N. Matsumoto; Y. Kuwahara

2003-01-01

20

GPR survey to confirm the location of ancient structures under the Valencian Cathedral (Spain)  

Microsoft Academic Search

This paper describes the ground-penetrating radar (GPR) survey performed inside the Cathedral of Valencia, Spain. It is part of historical studies performed in the Cathedral in order to add information to old maps and documents in the Cathedral Archives and also to analyze the extent and importance of potentially destructive moisture areas that were appearing on the floor. The construction

Vega Pérez Gracia; José Antonio Canas; Lluis G Pujades; Jaume Clapés; Oriol Caselles; Francesc Garc??a; Raul Osorio

2000-01-01

21

An Algorithm for Rapid Determination of Near-Fault Earthquake Deformation using LIDAR  

NASA Astrophysics Data System (ADS)

The recently-completed airborne lidar swath mapping (ALSM) survey of the southern San Andreas, San Jacinto and Banning faults (the "B4 survey") has delivered a high-resolution digital elevation model of 1100 km of the most seismically active fault systems in southern California for the express purpose of providing a baseline for post-earthquake slip determination. We used the B4 survey as a testbed to develop a processing algorithm that rapidly estimates near-fault coseismic ground deformation using simultaneous cross correlation of topography and backscatter intensity from pre/post-earthquake LIDAR datasets. We show robust recovery of the direction and magnitude of an applied synthetic slip of 5 m in the horizontal and 0.5 m in the vertical, with excellent discrimination between areas with and without applied slip. Our results indicate that we should be able to accurately recover horizontal slip ?0.5 m and vertical slip ?3 cm. We also used this algorithm to investigate misfit between overlapping B4 survey swaths in both the horizontal and vertical; our previous work in this area focused only on the vertical component of error. Significant calibration errors in geolocation resulted in across-swath elevation errors throughout the B4 survey of equal or greater magnitude than the expected vertical GPS error. This suggests that further research in calibration methods would have at least as much impact on survey accuracy as improving GPS trajectories and could greatly improve the recovery of the small vertical coseismic displacements expected in a strike-slip regime such as the San Andreas.

Borsa, A. A.; Minster, J. B.

2009-05-01

22

Acoustic Coupling Effects in ST Paul's Cathedral, London  

NASA Astrophysics Data System (ADS)

In St Paul's Cathedral there are many arches, columns and cornices which enable the internal space to be divided into subspaces. The subspaces may be considered to be acoustically coupled via areas which connect the rooms. Two of the most acoustically important subspaces in the Cathedral are the choir and the space under the dome. The choir, the space within the wooden choir stalls, has more sound absorption than the rest of the building, which is mostly marble and Portland stone. In the model of coupled subspaces an acoustic energy balance equation, applied to a diffuse field, is derived for each subspace. In St Paul's Cathedral the internal space is divided into 70 acoustical subspaces. The initial-value problem which is formulated by the system of 70 acoustic energy balance equations with initial conditions has been reduced to the eigenvalue problem. The decay of sound energy density has been obtained for different locations in the Cathedral and for different positions of the sound source. Experimentally obtained sound decay curves are in good agreement with numerical results. Both the experimental and numerical results demonstrate the fine structure of reverberation.

ANDERSON, J. S.; BRATOS-ANDERSON, M.

2000-09-01

23

Stable, rapid rate of slip since inception of the San Jacinto fault, California  

NASA Astrophysics Data System (ADS)

California, where the San Jacinto fault (SJF) and San Andreas fault (SAF) accommodate the majority of the dextral shear deformation between the Pacific and North American plates, initiation of the SJF led to an apparent decline in the slip rate of the SAF. Previous studies suggest that since then, slip rate has covaried between these faults (possibly due to changes in fault strength, variation in topographic loading along a fault, or the development of new faults) and that presently the SJF is the dominant plate boundary structure. However, we dated displaced sedimentary deposits and landforms over three distinct time intervals since ~700 ka, and our results imply a constant slip rate of 12.1+3.4/-2.6 mm/yr. This rate is similar to the fault's lifetime rate and from rates derived from geodesy, suggesting that since the SJF initiated, its slip rate has remained relatively stable and does not exceed that of the SAF.

Blisniuk, Kimberly; Oskin, Michael; MéRiaux, Anne-Sophie; Rockwell, Thomas; Finkel, Robert C.; Ryerson, Frederick J.

2013-08-01

24

A teleseismic study of the 2002 Denali fault, Alaska, earthquake and implications for rapid strong-motion estimation  

USGS Publications Warehouse

Slip histories for the 2002 M7.9 Denali fault, Alaska, earthquake are derived rapidly from global teleseismic waveform data. In phases, three models improve matching waveform data and recovery of rupture details. In the first model (Phase I), analogous to an automated solution, a simple fault plane is fixed based on the preliminary Harvard Centroid Moment Tensor mechanism and the epicenter provided by the Preliminary Determination of Epicenters. This model is then updated (Phase II) by implementing a more realistic fault geometry inferred from Digital Elevation Model topography and further (Phase III) by using the calibrated P-wave and SH-wave arrival times derived from modeling of the nearby 2002 M6.7 Nenana Mountain earthquake. These models are used to predict the peak ground velocity and the shaking intensity field in the fault vicinity. The procedure to estimate local strong motion could be automated and used for global real-time earthquake shaking and damage assessment. ?? 2004, Earthquake Engineering Research Institute.

Ji, C.; Helmberger, D. V.; Wald, D. J.

2004-01-01

25

Bacterial and fungal deterioration of the Milan Cathedral marble treated with protective synthetic resins  

Microsoft Academic Search

Surfaces are continuously exposed to physical, chemical and biological degradation. Among the biological agents that cause deterioration, microorganisms are of critical importance.This work is part of a research programme for the characterisation of the alterations of the Milan Cathedral (Italy). Four stone samples of the Milan Cathedral were chemically analysed and the microbiological growth assessed. X-ray diffraction (XRD) showed that

Francesca Cappitelli; Pamela Principi; Roberta Pedrazzani; Lucia Toniolo; Claudia Sorlini

2007-01-01

26

Finite-fault source inversion using teleseismic P waves: simple parameterization and rapid analysis  

USGS Publications Warehouse

We examine the ability of teleseismic P waves to provide a timely image of the rupture history for large earthquakes using a simple, 2D finite?fault source parameterization. We analyze the broadband displacement waveforms recorded for the 2010 Mw~7 Darfield (New Zealand) and El Mayor?Cucapah (Baja California) earthquakes using a single planar fault with a fixed rake. Both of these earthquakes were observed to have complicated fault geometries following detailed source studies conducted by other investigators using various data types. Our kinematic, finite?fault analysis of the events yields rupture models that similarly identify the principal areas of large coseismic slip along the fault. The results also indicate that the amount of stabilization required to spatially smooth the slip across the fault and minimize the seismic moment is related to the amplitudes of the observed P waveforms and can be estimated from the absolute values of the elements of the coefficient matrix. This empirical relationship persists for earthquakes of different magnitudes and is consistent with the stabilization constraint obtained from the L?curve in Tikhonov regularization. We use the relation to estimate the smoothing parameters for the 2011 Mw 7.1 East Turkey, 2012 Mw 8.6 Northern Sumatra, and 2011 Mw 9.0 Tohoku, Japan, earthquakes and invert the teleseismic P waves in a single step to recover timely, preliminary slip models that identify the principal source features observed in finite?fault solutions obtained by the U.S. Geological Survey National Earthquake Information Center (USGS/NEIC) from the analysis of body? and surface?wave data. These results indicate that smoothing constraints can be estimated a priori to derive a preliminary, first?order image of the coseismic slip using teleseismic records.

Mendoza, C.; Hartzell, S.

2013-01-01

27

Strain on the San Andreas fault near Palmdale, California: Rapid, aseismic change  

USGS Publications Warehouse

Frequently repeated strain measurements near Palmdale, California, during the period from 1971 through 1980 indicate that, in addition to a uniform accumulation of right-lateral shear strain (engineering shear, 0.35 microradian per year) across the San Andreas fault, a 1-microstrain contraction perpendicular to the fault that accumulated gradually during the interval 1974 through 1978 was aseismically released between February and November 1979. Subsequently (November 1979 to March 1980), about half of the contraction was recovered. This sequence of strain changes can be explained in terms of south-southwestward migration of a slip event consisting of the south-southwestward movement of the upper crust on a horizontal detachment surface at a depth of 10 to 30 kilometers. The large strain change in 1979 corresponds to the passage of the slip event beneath the San Andreas fault. Copyright ?? 1980 AAAS.

Savage, J. C.; Prescott, W. H.; Lisowski, M.; King, N. E.

1981-01-01

28

Rapid strain accumulation on the Ashkabad fault (Turkmenistan) from atmosphere-corrected InSAR  

NASA Astrophysics Data System (ADS)

We have measured interseismic deformation across the Ashkabad strike-slip fault using 13 Envisat interferograms covering a total effective timespan of ˜30 years. Atmospheric contributions to phase delay are significant and variable due to the close proximity of the Caspian Sea. In order to retrieve the pattern of strain accumulation, we show it is necessary to use data from Envisat's Medium-Resolution Imaging Spectrometer (MERIS) instrument, as well as numerical weather model outputs from the European Centre for Medium-Range Weather Forecasts (ECMWF), to correct interferograms for differences in water vapor and atmospheric pressure, respectively. This has enabled us to robustly estimate the slip rate and locking depth for the Ashkabad fault using a simple elastic dislocation model. Our data are consistent with a slip rate of 5-12 mm/yr below a locking depth of 5.5-17 km for the Ashkabad fault, and synthetic tests support the magnitude of the uncertainties on these estimates. Our estimate of slip rate is 1.25-6 times higher than some previous geodetic estimates, with implications for both seismic hazard and regional tectonics, in particular supporting fast relative motion between the South Caspian Block and Eurasia. This result reinforces the importance of correcting for atmospheric contributions to interferometric phase for small strain measurements. We also attempt to validate a recent method for atmospheric correction based on ECMWF ERA-Interim model outputs alone and find that this technique does not work satisfactorily for this region when compared to the independent MERIS estimates.

Walters, R. J.; Elliott, J. R.; Li, Z.; Parsons, B.

2013-07-01

29

Fluorescence lidar imaging of the cathedral and baptistery of Parma  

NASA Astrophysics Data System (ADS)

Extensive fluorescence multispectral imaging of the cathedral and baptistery of Parma, Italy, is reported and discussed. In particular, the first fluorescence imaging data from protection-treated stony materials were recorded. Fluorescence spectra were taken with a mobile lidar system scanning the monument surfaces with a frequency-tripled Nd:YAG laser beam from a distance of about 80 m. For each pixel of the area investigated, a high-spectral-resolution spectrum in the full visible range was acquired. The principal-component analysis technique was used to obtain thematic maps that outlined areas subject to protective treatment and biological growth, and other features, such as different types of stones and decoration pigments.

Lognoli, D.; Cecchi, G.; Mochi, I.; Pantani, L.; Raimondi, V.; Chiari, R.; Johansson, T.; Weibring, P.; Edner, H.; Svanberg, S.

30

Stability and localization of rapid shear in fluid-saturated fault gouge: 1. Linearized stability analysis  

NASA Astrophysics Data System (ADS)

Field observations of major earthquake fault zones show that shear deformation is often confined to principal slipping zones that may be of order 1-100 ?m wide, located within a broader gouge layer of order 10-100 mm wide. This paper examines the possibility that the extreme strain localization observed may be due to the coupling of shear heating, thermal pressurization, and diffusion. In the absence of a stabilizing mechanism shear deformation in a continuum analysis will collapse to an infinitesimally thin zone. Two possible stabilizing mechanisms, studied in this paper, are rate-strengthening friction and dilatancy. For rate-strengthening friction alone, a linear stability analysis shows that uniform shear of a gouge layer is unstable for perturbations exceeding a critical wavelength. Using this critical wavelength we predict a width for the localized zone as a function of the gouge properties. Taking representative parameters for fault gouge at typical centroidal depths of crustal seismogenic zones, we predict localized zones of order 5-40 ?m wide, roughly consistent with field and experimental observations. For dilatancy alone, linearized strain rate perturbations with a sufficiently large wavelength will undergo transient exponential growth before decaying back to uniform shear. The total perturbation strain accumulated during this transient strain rate localization is shown to be largely controlled by a single dimensionless parameter E, which is a measure of the dilatancy of the gouge material due to an increase in strain rate.

Rice, James R.; Rudnicki, John W.; Platt, John D.

2014-05-01

31

Rapid fault model estimation based on RTK-GPS and its application to near-field tsunami forecasting  

NASA Astrophysics Data System (ADS)

The 2011 off the Pacific coast of Tohoku Earthquake (Mw 9.0) generated a huge tsunami that inflicted enormous damage on the Pacific side of Tohoku region. Three minutes after the earthquake, the Japan Meteorological Agency issued a tsunami warning based on the seismic data. The estimated maximum tsunami heights (up to 6 m), however, were clearly smaller than the observed one (more than 10 m) because of underestimation of the earthquake magnitude. The magnitude can be derived within a short period following the earthquake, which can saturate for such great earthquakes. This example clearly shows necessity of accurate tsunami early warning system and importance of the rapid determination of reliable earthquake sizes. Blewitt et al. [GRL, 2006] already pointed out that a true earthquake size and its tsunamigenic potential could be determined using GPS data. The permanent displacement directly tells us the true earthquake size information. It is the great advantage of the GPS compared with the seismometer even though the signal-to-noise ratio is lower than it. Based on these backgrounds, we newly developed an algorithm to detect/estimate static ground displacement due to earthquake faulting from real time kinematic GPS (RTK-GPS) time series for quasi real-time determination of seismic fault model. We use the method using comparison between short-term and long-term average, which is generally used for automatic detection of seismic waves. Before its practical application, we assessed the noise property of the RTK-GPS time series with various conditions such as baseline lengths, GPS satellites ephemerides, etc., with analysis software "RTKLIB 2.4.0" [http://www.rtklib.com] to show that the ultra-rapid ephemerides distributed by the international GNSS Service result in enough precision for the crustal deformation monitoring with long baselines up to 1,000 km. We applied the algorithm to the GPS data obtained in the Tohoku Earthquake to assess its ability of event detection and performance of fault model estimation. The maximum baseline length is about 900 km. Detection and calculation of the coseismic displacements finished at all sites within about 4.5 min from origin time. Estimation of parameters of a rectangular fault with a uniform slip was also carried out every 20 sec to give the final earthquake magnitude reaching Mw 8.7, which is close to actual one (9.0). Once the fault model is estimated, tsunami waveforms can be synthesized within 1 min by using pre-computed tsunami Green's functions for initial displacement of elementary sea-surface sources [Tsushima et al., Ocean Science Meeting, 2010]. The calculated waveforms show good agreement with the observed tsunami both in arrival times and wave heights at coastal tide gauge stations in near field. In the Tohoku earthquake, tsunami height calculation based on seismic fault model was capable within 6 min from the origin time. These tsunami predictions can be provided 20 min before the actual tsunami attack in this case. The time in advance can save people in the coastal area by providing enough time for evacuation.

Kobayashi, T.; Ohta, Y.; Miura, S.; Tsushima, H.; Hino, R.; Takasu, T.; Fujimoto, H.

2011-12-01

32

Rapid, decimeter-resolution fault zone topography mapped with Structure from Motion  

NASA Astrophysics Data System (ADS)

Recent advances in the generation of high-resolution topography have revolutionized our ability to detect subtle geomorphic features related to ground-rupturing earthquakes. Currently, the most popular topographic mapping methods are airborne Light Detection And Ranging (LiDAR) and terrestrial laser scanning (TLS). Though powerful, these laser scanning methods have some inherent drawbacks: airborne LiDAR is expensive and can be logistically complicated, while TLS is time consuming even for small field sites and suffers from patchy coverage due to its restricted field-of-view. An alternative mapping technique, called Structure from Motion (SfM), builds upon traditional photogrammetry to reproduce the topography and texture of a scene from photographs taken at varying viewpoints. The improved availability of cheap, unmanned aerial vehicles (UAVs) as camera platforms further expedites data collection by covering large areas efficiently with optimal camera angles. Here, we introduce a simple and affordable UAV- or balloon-based SfM mapping system which can produce dense point clouds and sub-decimeter resolution digital elevation models (DEMs) registered to geospatial coordinates using either the photograph's GPS tags or a few ground control points across the scene. The system is ideally suited for studying ruptures of prehistoric, historic, and modern earthquakes in areas of sparse or low-lying vegetation. We use two sites from southern California faults to illustrate. The first is the ~0.1 km2 Washington Street site, located on the Banning strand of the San Andreas fault near Thousand Palms. A high-resolution DEM with ~700 point/m2 was produced from 230 photos collected on a balloon platform flying at 50 m above the ground. The second site is the Galway Lake Road site, which spans a ~1 km strip of the 1992 Mw 7.3 Landers earthquake on the Emerson Fault. The 100 point/m2 DEM was produced from 267 photos taken with a balloon platform at a height of 60 m above the ground. We compare our SfM results to existing airborne LiDAR or TLS datasets. Each SfM survey required less than 2 hours for setup and data collection, an allotment much lower than that required for TLS data collection, given the size of the sites. Processing time is somewhat slower, but depends on the quality of the DEM desired and is almost fully automated. The SfM point cloud densities we present are comparable to TLS but exceed the density of most airborne LiDAR and the orthophotos (texture maps) from the SfM are valuable complements to the DEMs. The SfM topography illuminates features along the faults that can be used to measure offsets from past ruptures, offering the potential to enhance regional seismic hazard analyses.

Johnson, K. L.; Nissen, E.; Saripalli, S.; Arrowsmith, R.; McGarey, P.; Scharer, K. M.; Williams, P. L.

2013-12-01

33

Real-time magnitude estimation and rapid fault characterization with GPS data for Earthquake Early Warning applications  

NASA Astrophysics Data System (ADS)

The combined use of seismic and geodetic observations is now a common practice for finite-fault modeling and seismic source parametrization. With the advent of high-rate 1Hz GPS stations the seismological community has begun to look at ways to include GPS data in Earthquake Early Warning (EEW) algorithms. GPS stations record ground displacement without any risk of saturating or need for baseline or other corrections. Thus, geodetic displacement timeseries complement the high-frequency information provided by seismic data. In the standard approaches to early warning, the initial portion of the P-wave signal is used to rapidly characterize the earthquake magnitude and to predict the expected ground shaking at a target site, before damaging waves arrive. Whether the final magnitude of an earthquake can be predicted while the rupture process is underway, still represents a controversial issue; the point is that the limitations of the standard approaches when applied to giant earthquakes have become evident after the experience of the Mw 9.0, 2011 Tohoku-Oki earthquake. Here we explore the application of GPS data to EEW and investigate whether the co-seismic ground deformation can be used to provide fast and reliable magnitude estimations. We implemented an algorithm to extract the permanent static offset from GPS displacement timeseries; the static displacement is then used to invert for the slip distribution on the fault plane, using a constant-slip, rectangular source embedded in a homogeneous half-space. We developed an efficient real-time static slip inversion scheme for both the rapid determination of the event size and for the near real-time estimation of the rupture area. This would allow for a correct evaluation of the expected ground shaking at the target sites, which represents, without doubt, the most important aspect of the practical implementation of an early warning system and the most relevant information to be provided to non-expert end-users. The strategy we propose is fairly robust and does not need any predefined geometry or restrictive prior assumptions; the starting model is a simple fault plane divided into a limited number of patches. The geometry and dimensions are determined as soon as the first magnitude estimation from near-field seismic stations is available. The methodology is expected to be suitable for any seismically active area and can be easily incorporated into a real-time Earthquake Early Warning System.

Colombelli, S.; Allen, R. M.; Zollo, A.

2012-12-01

34

Rapid Deployment with Confidence: Calibration and Fault Detection in Environmental Sensor Networks  

Microsoft Academic Search

Rapidly deployable sensor networks are portable, reusable, and can take advantage of a human user in the field attending to the deployment. Unfortunately, even small disruptions or problems in collected data must be addressed quickly, as the overall quantity of data gathered is small relative to long- term deployments. In this paper we describe a procedure for calibration and a

Nithya Ramanathan; Laura Balzano; Marci Burt; Deborah Estrin; Tom Harmon; Charlie Harvey; Jenny Jay; Eddie Kohler; Sarah Rothenberg; Mani Srivastava

2006-01-01

35

RAPID  

Cancer.gov

Rapid Access to Preventive Intervention Development (RAPID) Program About RAPID Description and Objectives of the Program Oversight RAPID Is Not... Frequently Asked Questions Application Information Format of Applications Address for Applications

36

In situ investigations of vault paintings in the Antwerp cathedral  

NASA Astrophysics Data System (ADS)

X-ray fluorescence spectroscopy (XRF) and Raman spectroscopy have been used to examine 15th century mediaeval and 16th century renaissance vault paintings in the Our Lady's Cathedral (Antwerp, Belgium) in view of their restoration. The use of mobile instruments made it possible to work totally non-destructively. This complementary approach yields information on the elemental (XRF) and on the molecular composition (Raman) of the pigments. For the 15th century vault painting the pigments lead-tin yellow (Pb 2SnO 4), lead white (2PbCO 3·Pb(OH) 2), vermilion (HgS), massicot (PbO) and azurite (2CuCO 3·Cu(OH) 2) could be identified. The pigments used for the 16th century vault painting could be identified as red lead (Pb 3O 4), hematite (Fe 2O 3), lead white (2PbCO 3·Pb(OH) 2) and azurite (2CuCO 3·Cu(OH) 2). For both paintings the presence of the strong Raman scatterer calcite (CaCO 3) resulted in a difficult identification of the pigments by Raman spectroscopy. The presence of gypsum (CaSO 4·2H 2O) on the mediaeval vault painting probably indicates that degradation took place.

Deneckere, Annelien; Schudel, Walter; Van Bos, Marina; Wouters, Helena; Bergmans, Anna; Vandenabeele, Peter; Moens, Luc

2010-02-01

37

Lidar remote sensing of the Parma Cathedral and Baptistery  

NASA Astrophysics Data System (ADS)

Fluorescence lidar is a well known instrument that is mainly employed for the remote sensing of the Earth's surface. In recent years, IROE, in collaboration with other Italian and foreign institutions, carried out the first experiments on remote sensing of historical buildings using fluorescence lidar. The main part of these experiments deals with the remote monitoring of biodeteriogens and the lithological characteristics of the building materials. This paper describes the results of the field experiment carried out at the Parma Cathedral and Baptistery in September 2000. Two systems, the tripled Nd:YAG lidar of the Lund Institute of Technology and the XeCl lidar of the CNR-IROE, operated for one week, in order to test the possible applications of both fluorescence point measurement and fluorescence thematic imaging in the remote non-destructive monitoring of buildings. Apart from confirming the possibility of detecting biodeteriogens, for the first time in our knowledge the processing of the fluorescence data made possible the detection of restorations and the distinction between pigments having the same color.

Weibring, Petter K.; Lognoli, David; Chiari, Roberto; Cecchi, Giovanna; Edner, Hans; Johansson, Thomas; Pantani, Luca; Svanberg, Sune; Tirelli, Daniele; Trambusti, Massimo

2001-10-01

38

The role of dyking and fault control in the rapid onset of eruption at Chaitén volcano, Chile.  

PubMed

Rhyolite is the most viscous of liquid magmas, so it was surprising that on 2?May 2008 at Chaitén Volcano, located in Chile's southern Andean volcanic zone, rhyolitic magma migrated from more than 5?km depth in less than 4?hours (ref.?1) and erupted explosively with only two days of detected precursory seismic activity. The last major rhyolite eruption before that at Chaitén was the largest volcanic eruption in the twentieth century, at Novarupta volcano, Alaska, in 1912. Because of the historically rare and explosive nature of rhyolite eruptions and because of the surprisingly short warning before the eruption of the Chaitén volcano, any information about the workings of the magmatic system at Chaitén, and rhyolitic systems in general, is important from both the scientific and hazard perspectives. Here we present surface deformation data related to the Chaitén eruption based on radar interferometry observations from the Japan Aerospace Exploration Agency (JAXA) DAICHI (ALOS) satellite. The data on this explosive rhyolite eruption indicate that the rapid ascent of rhyolite occurred through dyking and that melt segregation and magma storage were controlled by existing faults. PMID:22012396

Wicks, Charles; de la Llera, Juan Carlos; Lara, Luis E; Lowenstern, Jacob

2011-10-20

39

The Grammar School at the Cathedral of the Canary Islands (1563-1851)  

ERIC Educational Resources Information Center

From 1563 until the death of the last teacher in 1851, there was a prebendary in the Cathedral of the Canary Islands in charge of the education of children. In fact, it could be said that this prebendary was the only continuous secondary school teacher there was in the Canary Islands until the beginning of the nineteenth century when the High…

Vera-Cazorla, Maria Jesus

2013-01-01

40

The effect of air pollution on the stone decay of the Cologne Cathedral  

NASA Astrophysics Data System (ADS)

Different building stones of the Cologne Cathedral show a large variation of weathering phenomena. The Drachenfels trachyte, which was the construction material for the medieval part of the cathedral, shows significant surface deterioration, back-weathering coexisting with flaking, crumbling or the massive formation of gypsum crusts. Wolff (1992) first mentioned the negative interferences between the Schlaitdorfer sandstone and the Londorfer basalt lava or the Drachenfels trachyte and the Krensheimer muschelkalk. Crust formation on limestone, sandstone, and volcanic rock from the Cologne Cathedral as well as from the Xanten and Altenberg Cathedral are investigated. These three buildings are located in different areas and exposed to varying industrial, urban, and rural environmental situations. The material investigated range from dark grey to black framboidal crusts. This 3 to 10 mm thick cauliflower-like form of gypsum crust incorporates particles from the pollution fluxes. It covers the stone surface and mainly occurs at sites protected from wind and direct rain. Secondly, thin laminar black crusts trace the stone surface and may cover complete sections of the building's structure not necessarily preferring protected sites. This kind of crust seems to have very strong bonds between the thin black crust and the stone surface. Major and trace element distribution show an enrichment of sulfur, indicating the presence of gypsum, lead and other typical pollutants (arsenic, antimony, bismuth, tin etc.), which generally can be linked to traffic and industry. This indicates that even though the SO2 emission has decreased due to i.e. stronger regulations of waste incineration plants and the ban of leaded petrol, the pollutants are still present in the crusts on the building stones. From systematic SEM observations it becomes evident that the total amount of pollution is less pronounced in the Altenberg and Xanten Cathedrals as compared with the Cologne Cathedral. The formation of gypsum occurs at lower amounts in Altenberg, which correlates well with the measured SO2 content. On the other hand, the increasing H2O content in the trachyte and the crusts correlates well with an increasing phyllosilicate formation. Through the combination of different analytical techniques it was possible to clearly distinguish samples from the industrial or rural environment. If the data is compared to actual pollutant emissions, the analyzed samples imply present but also past pollution fluxes. Thus, the soiled zones of the built environment can function as environmental indicators.

Graue, B.; Siegesmund, S.; Licha, T.; Simon, K.; Oyhantcabal, P.; Middendorf, B.

2012-04-01

41

Exeter Cathedral Keystones and Carvings: A Catalogue Raisonne of the Sculptures & Their Polychromy  

NSDL National Science Digital Library

Exeter Cathedral Keystones and Carvings functions as "an illustrated introduction to, and explanatory catalogue of all the figurative sculpture that is part of the original interior fabric of the medieval building." The material on the site, which is primarily geared toward art historians and medievalists, was compiled by Avril Kay Henry, former professor of English Medieval Culture at University of Exeter, and the late Anna Carson Hulbert, a well known conservator. The site does not provide a tour through the cathedral so much as it offers photos and explanations of the individual sculptural pieces: "medieval bosses, corbels, labelstops, figurative capitals (and a few other interior carvings) which are an integral part of the medieval interior construction of Exeter Cathedral, Devon, England." Users can browse or search the contents, and a nice introduction and bibliography are both useful supplements. From the homepage, users can access a page that explains navigation and layout of the site, entitled The Resource: Coverage and Use. This one is well worth a stop for medievalists.

Henry, Avril.; Hulbert, Anna C.

2001-01-01

42

Rapid estimation of fault parameters for tsunami warning along the Mexican subduction zone based on real-time GPS (Invited)  

NASA Astrophysics Data System (ADS)

A reliable and robust tsunami early warning is now possible thanks to the availability of real-time GPS data. With few assumptions regarding the characteristics of the geometry of the subduction interface (dip, width of the seismogenic zone, and maximum depth of the seismically-coupled interface), we can estimate the length, L, and the width, W, of the rupture, as well as its downdip extension, C (Singh et al., 2008; 2012). These are estimated from the amplitude of the observed horizontal displacement along the coast and its fall off with distance, as well as the polarity of the vertical displacement. Based on Okada's (1992) model, we compute the slip D on the fault, to finally obtain the seismic moment, Mo. Pérez-Campos et al. (2013) showed the feasibility of such tsunami early warning for the Mexican subduction zone. Mo could be obtained in ~2 min after origin time from a dense distribution of real-time high-rate GPS stations along the coast. However, the current GPS network is sparse. Despite this, a robust estimate of magnitude Mw can be obtained. For this work, we perform sensitivity tests for Mw and position of the fault with respect to the trench.

Perez-Campos, X.; Singh, S. K.; Melgar, D.; Cruz Atienza, V. M.; Iglesias, A.; Hjorleifsdottir, V.

2013-12-01

43

Testing of a rapid fault detection model for quality control: Borophosphosilicate glass thin films monitored by infrared absorption spectroscopy  

SciTech Connect

Infrared absorption spectra of 108 borophosphosilicate glass (BPSG) thin films produced in a multiple-wafer low-pressure chemical vapor deposition (LPCVD) reactor were collected to enable the development and testing of a rapid and inexpensive method for determining if films are within the desired specifications. Classification of samples into good and bad product categories was made by applying principal component analysis to the spectra. Mahalanobis distances were used as the classification metric. The highest overall percentage of correct classification of samples based upon their spectra with two-step classification was 95{percent}. The misclassified samples were, however, within the error of the reference methods that were used in making the original classification against which the infrared (IR) classification methods were tested. The classification errors are thus just as likely to be a result of misclassification by the reference method rather than errors by the IR classification. Although reference measurements were used in this article for the original classification of the samples, these expensive and time-consuming reference methods can be eliminated simply by building classification models on samples determined to produce a product within the correct device specifications. The IR classification methods presented here hold great promise as a tool for rapid quality control of BPSG deposition. {copyright} {ital 1997 American Vacuum Society.}

Zhang, S.; Franke, J.E.; Niemczyk, T.M. [Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131 (United States)] [Department of Chemistry, University of New Mexico, Albuquerque, New Mexico 87131 (United States); Haaland, D.M. [Sandia National Laboratories, Albuquerque, New Mexico 87185-0342 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185-0342 (United States); Cox, J.N.; Banerjee, I. [Intel Corporation, 3065 Bowers Avenue, Santa Clara, California 95052 (United States)] [Intel Corporation, 3065 Bowers Avenue, Santa Clara, California 95052 (United States)

1997-07-01

44

Examples of weathering and deterioration of Tertiary building stones at St. Michaels Cathedral in Cluj-Napoca (Romania)  

Microsoft Academic Search

St. Michaels Cathedral is one of the oldest Gothic architectural monuments in Cluj. It is built predominantly of Cenozoic (Eocene) limestones which were deposited on a shallow carbonate platform. They are composed of different facies and microfacies types with varying amounts of particles, matrix and cement. Limestones from the Baci quarry (Cluj Limestone), which is situated about 3 km from

Roman Koch; Paul Calin Racataianu; Ioan I. Bucur

2008-01-01

45

Crowning the Cathedral of Florence: Brunelleschi Builds His Dome. A Unit of Study for Grades 7-10.  

ERIC Educational Resources Information Center

This unit focuses on a dramatic moment in the Renaissance from about 1420 when Filippo Brunelleschi single handedly created, defined, and engineered a new architecture by building the great dome of the cathedral of Santa Maria del Fiore in Florence. The dome became the symbol of Florence's grandeur during the Renaissance, and a model for great…

Symcox, Linda

46

Imperial Designs, Post-Colonial Replications: Class and Power at Cathedral and John Connon School in Bombay  

ERIC Educational Resources Information Center

Utilizing a framework which employs symbolic capital and post-colonial analysis, this paper examines the cultural meanings of English-language education at Cathedral and John Connon School in Bombay, India. The central question this article seeks to address is how power is replicated through education and, more specifically, the ways in which…

Dewey, Susan

2006-01-01

47

Photogrammetric and LIDAR Documentation of the Royal Chapel Cathedral-Mosque of Cordoba, Spain)  

NASA Astrophysics Data System (ADS)

At present, cultural heritage documentation projects use a variety of spatial data acquisition techniques such as conventional surveying, photogrammetry and terrestrial laser scanning. This paper deals with a full documentation project based on all those techniques in the Royal Chapel located in the Cathedral-Mosque of Cordoba in Spain, declared World Heritage Site by UNESCO. At present, the Royal Chapel is under study for a detailed diagnostic analysis in order to evaluate the actual state of the chapel, pathologies, construction phases, previous restoration works, material analysis, etc. So in order to assist the evaluation, a documentation project with photogrammetric and laser scanner techniques (TLS) has been carried out. With this purpose, accurate cartographic and 3D products, by means of the integration of both image and laser based techniques, were needed to register all data collected during the diagnostic analysis.

Cardenal, J.; Perez-Garcia, J. L.; Mata, E.; Hernandez, M. A.; Mozas, A.; Delgado, J.; Lopez-Arenas, A.; Meroño, J. E.

2012-07-01

48

Vertical distribution of air pollutants at the Gustavii Cathedral in Göteborg, Sweden  

NASA Astrophysics Data System (ADS)

Atmospheric trace gases and particles were measured at two heights at the Gustavii Cathedral in Göteborg, Sweden, during 7 weeks in September and October 1999. The Gustavii Cathedral is situated in the city centre of Göteborg, which is near the harbour area and encircled by heavy traffic some hundred metres away. The main body of the church is as high as the surrounding buildings, while the tower extends well above. The sampling points were placed on the west wall of the tower at 10 and 32 m height, i.e. well below and above the roof top level of surrounding buildings, respectively. Sulphur dioxide and nitric acid were sampled using the denuder technique and analysed by Ion Chromatography, IC. Total suspended particulates (TSP) were sampled using filter cups and subsequently analysed by energy dispersive X-ray fluorescence spectroscopy (EDXRF). In addition to the diurnal sampling of species, nitrogen oxides were measured using chemiluminescence detectors. Additional data from the Environmental Office in Göteborg was used in the analysis. Differences between the concentrations measured at the upper and lower levels were calculated and their variation and dependence on meteorological factors were evaluated. On the average larger concentrations were found at the lower level for soil derived elements and TSP, while nitric acid and nitric oxide showed larger concentrations at the upper level. Sulphur dioxide and nitrogen dioxide, as well as many of the elements in the TSP, showed equal concentrations at the two levels. However, depending on wind direction the measured differences of nitrogen oxides could be both positive and negative.

Janhäll, Sara; Molnár, Peter; Hallquist, Mattias

49

Bacterial and fungal deterioration of the Milan Cathedral marble treated with protective synthetic resins.  

PubMed

Surfaces are continuously exposed to physical, chemical and biological degradation. Among the biological agents that cause deterioration, microorganisms are of critical importance. This work is part of a research programme for the characterisation of the alterations of the Milan Cathedral (Italy). Four stone samples of the Milan Cathedral were chemically analysed and the microbiological growth assessed. X-ray diffraction (XRD) showed that calcite was always present in each sample and one sample was also characterised by the chemical form of alteration gypsum. Using Fourier Transform Infrared Spectroscopy (FTIR) together with Scanning Electron Microscopy (SEM), it was possible to prove that the samples were consolidated with the synthetic acrylics and epoxy resins. The green-black biological patinas of the specimens were studied using cultivation, microscope observations and a method for single-cell detection. Sampling for fluorescent in-situ hybridisation (FISH), with ribosomal RNA targeted oligonucleotide probes, was also performed using adhesive tapes. The bulk of the prokaryotes were Bacteria but some Archaea were also found. The bacterial cells were further characterised using specific probes for Cyanobacteria, and alpha-, beta-and gamma-Proteobacteria. In addition, black fungi isolated from the stone and the fungi of the standard ASTM G21-96(2002) method were employed to test if the detected synthetic resins could be used as the sole source of carbon and energy. One isolated Cladosporium sp. attacked the freshly dried acrylic resin. Results show that the detected bacteria and fungi can cause severe damage both to the stone monument and its synthetic consolidants. PMID:17658586

Cappitelli, Francesca; Principi, Pamela; Pedrazzani, Roberta; Toniolo, Lucia; Sorlini, Claudia

2007-10-15

50

Detection and Elimination of Cyanobacteria from Frescoes: The Case of the St. Brizio Chapel (Orvieto Cathedral, Italy)  

Microsoft Academic Search

A rosy discoloration partly masking the Luca Signorelli frescoes in St. Brizio Chapel (Orvieto Cathedral, Italy) for many\\u000a years proved to be a biological alteration, so the present research focused on investigating biodeteriogens and selecting\\u000a an appropriate biocide to treat them. Optical epifluorescence and electronic microscopic observations of the rosy powder revealed\\u000a a prevalent autofluorescent coccoid form with a diameter

F. Cappitelli; P. Abbruscato; P. Foladori; E. Zanardini; G. Ranalli; P. Principi; F. Villa; A. Polo; C. Sorlini

2009-01-01

51

North Anatolian Fault in the Gulf of Izmit (Turkey): Rapid vertical motion in response to minor bends of a nonvertical continental transform  

NASA Astrophysics Data System (ADS)

The catastrophic rupture of the North Anatolian Fault east of the Marmara Sea on 17 August 1999 highlighted a need for mapping the underwater extension of that continental transform. A new bathymetric map of Izmit Gulf indicates that the fault follows the axis of the gulf with a few minor bends. Submerged shorelines and shelf breaks that formed during the Last Glacial Maximum provide markers to quantify vertical deformation. Variable tilting of these horizons reveals that vertical deformation is highest just south of the fault. A correlation between vertical deformation of the southern fault block and distance to fault bends can be accounted for by a fault dipping steeply to the south. Hence subsidence (uplift) of the southern, hanging wall block would be expected where the fault strikes at a slightly transtensional (transpressional) orientation to relative plate motion. Subsidence reaches about 8 mm/yr west of the town of Golcuk and might be accommodated in 1-2 m subsidence events during large earthquakes. That scenario is compatible with the tsunami runups and the coseismic subsidence of the southern shore that occurred in 1999. Seafloor morphology also suggests that earthquakes are accompanied by widespread gas and fluid release. The periphery of the deepest basin displays a hummocky texture diagnostic of sediment fluidization, and mud volcanoes occur west of Hersek peninsula that might be activated by earthquakes. Finally, the backscatter imagery reveals a series of lineaments midway through the gulf that are interpreted as products of the 1999 surface rupture. The seafloor is undisturbed farther west, suggesting that surface slip decreased to an insignificant level beyond Hersek. Possibly, the stress shadow from the 10 July 1894 earthquake, which was felt strongly along the western Izmit Gulf, contributed to arrest the 1999 surface rupture.

Cormier, Marie-Helene; Seeber, Leonardo; McHugh, Cecilia M. G.; Polonia, Alina; ?Agatay, Namik; Emre, Ã.-Mer; Gasperini, Luca; GöRür, Naci; Bortoluzzi, Giovanni; Bonatti, Enrico; Ryan, William B. F.; Newman, Kori R.

2006-04-01

52

Acoustic conditioning of the metropolitan cathedral of Porto Alegre, RS, Brazil  

NASA Astrophysics Data System (ADS)

In the acoustic study of the Metropolitan Cathedral of Porto Alegre, RS, Brazil, initially background noise and reverberation time were measured. A digital model was built using acoustic simulation software AcustaCadd, applying the values of the measured reverberation time. Then reverberation time, speech intelligibility, and geometric acoustics were analyzed. As a result the Project of Acoustic Conditioning was developed to correct the high reverberation time, by increasing absorption with the installation of 65000 m of panels of glass wool (100 mm, 60 kg/m). Advantage was taken of existing details in the plaster to embed the panels in the walls. Also the volume of the choir and of the lateral balcony to the altar was reduced and the interior of this was covered with the same glass wool. Special care was taken to minimize alterations to the architectural characteristics of the place, because it is a construction of historical importance. The measured values of background noise were also analyzed and appropriate acoustic isolation considered. The final measure of the reverberation time showed an average reduction of 5 seconds and better speech intelligibility, long demanded by the users. [Work supported by FAIR/FUNDATEC, BR; IUCC-US, SP.

Simoes, Flavio M.; Nabinger, Luciano B.; Ramalho, Aline I.

2002-11-01

53

An in situ corrosion study of Middle Ages wrought iron bar chains in the Amiens Cathedral  

NASA Astrophysics Data System (ADS)

The corrosion behaviour of Middle Ages wrought iron bar chains exposed to indoor atmospheric corrosion for hundred of years in the Notre Dame Cathedral of Amiens (France) has been evaluated by means of Electrochemical Impedance Spectroscopy (EIS), a well-established electrochemical technique extensively used for testing anticorrosive properties of metal coatings. The measurements have been performed in situ with a portable EIS instrument designed to work as a standalone device, in six different areas of the wrought iron bar chains characterized by different aesthetical appearance. Moreover, a properly designed electrochemical cell has been employed to carry out the impedance measurements without affecting the artefacts surfaces. The wrought iron bar chains, as evidenced by ?-Raman and microscopic analyses, are covered by corrosion products constituted by iron oxides and oxyhydroxides, such as goethite, lepidocrocite, maghemite, akaganeite, organized in complex layered structures. In situ EIS allows one to investigate the phenomena involved at the electrochemical interfaces among the various corrosion products and to assess and predict their corrosion behaviour. From the analysis of the experimental findings of this monitoring campaign, EIS measurements can be proposed to restorers/conservators as a reliable indicator of dangerous situations on which they must act for the preservation of the iron artefacts.

Grassini, S.; Angelini, E.; Parvis, M.; Bouchar, M.; Dillmann, P.; Neff, D.

2013-12-01

54

Monitoring of the Heat and Moisture Transport through Walls of St. Martin Cathedral Tower in Bratislava  

NASA Astrophysics Data System (ADS)

Historic monuments are subject to degradation due to exposition to surrounding meteorological conditions and groundwater. Construction of buildings consists of the plaster and material components that have porous structure. Processes like heat transport, moisture diffusion, moisturizing and drying; freezing and thawing can be found in such structures depending on environmental conditions. Monitoring of the temperature - moisture regime gives a picture on the processes running in the structure. Long term monitoring of the tower of St. Martin Cathedral in Bratislava have been performed under window sill of the belfry in exterior in south orientation. Principle of the hot-ball method is used for monitoring of the temperature and thermal conductivity. The thermal conductivity of the porous system depends on the pore content. Moisture sensors are constructed from the parent material in a form of cylinder. Sensors are calibrated for dry and water saturated stage prior installation in the walls. Monitoring has been carried out in plaster and in the masonry in a distance about 10 cm from the wall surface, where sensors are installed. Information on temperature, moisture and thermal conductivity can be gained from measured signal. Use of two sensors allows estimation on heat and moisture transport through the wall. Monitoring has been performed in the period from April 2013 up to July 2013. Monitored data are correlated to the meteorological data. Details of various effects will be discussed.

Kubi?ár, ?udovít; Hudec, Ján; Fidríková, Danica; Štofanik, Vladimír; Dieška, Peter; Vretenár, Viliam

2014-05-01

55

Millennial slip-rates along the eastern Kunlun fault and rapid evolution of channel morphology in the yellow river headwaters, northeastern Tibet, China  

NASA Astrophysics Data System (ADS)

A mechanical description of the interplay between ongoing crustal deformation and topographic evolution within the Tibetan Plateau remains outstanding, and thus our ability to describe the mechanisms responsible for the creation of this and other continental plateaus is limited. In this work, we employ a multidisciplinary approach to investigate the Quaternary record of active tectonism and coeval topographic evolution in the northeastern Tibetan Plateau. Fluvial channel topographic data paired with geochronologically calibrated measures of erosion rate reveal a headward migrating wave of dramatically accelerated incision rates in the headwaters of the Yellow River, which drains a large portion of northeastern Tibet. This transient increase in incision is likely driven by downstream base-level changes along the plateau margin and is superimposed onto a broad region of higher erosion rates confined to the plateau itself, within the Anyemaqen Shan (mountains). The Kunlun fault, one of the major active strike-slip faults of Tibet, trends through the Anyemaqen Shan. Using a careful approach towards quantifying millennial slip-rates along this fault zone based on the age of offset landforms, we constrain the Pleistocene kinematics of the eastern portion of the Kunlun fault and link this deformation to tectonically-driven erosion in the Anyemaqen Shan. Consideration of the age and morphology of fluvial terraces offset by the fault both highlights uncertainties associated with slip-rate determinations and allow more confident quantification of the allowable range of slip-rates at sites that take advantage of these features. Several new slip-rate determinations from this study at select locations corroborate a small number of previous determinations to identify an eastward decreasing slip-rate gradient and termination of the Kunlun fault within the Anyemaqen Shan. Existing geodetic data reveals a similar pattern of eastward-decreasing distributed shear across the fault zone. The spatial coincidence of tectonically driven erosion in the Anyemaqen Shan with the slip-rate gradient and termination the Kunlun fault implies that the crust of the northeastern plateau has the ability to accumulate regionally distributed permanent strain. Therefore, traditional 'rigid-body' rotation type descriptions of Tibetan Plateau kinematics fail to describe deformation on the northeastern plateau.

Harkins, Nathan W.

56

Fault finder  

DOEpatents

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.

Bunch, Richard H. (1614 NW. 106th St., Vancouver, WA 98665) [1614 NW. 106th St., Vancouver, WA 98665

1986-01-01

57

Laser Scanning for the Geometric Study of the ALCÁNTARA Bridge and Coria Cathedral  

NASA Astrophysics Data System (ADS)

The conservation of built heritage is becoming increasingly important, and may even be an obligation for future generations. Techniques must therefore be developed to help document heritage and thus improve knowledge and conservation. The terrestrial laser scanning technique allows a massive capture of points of an object. Among its main applications are to obtain geometries of historic buildings and monuments, allowing the documentation of their heritage. But this technique also facilitates other very important information for the conservation of the monument in question from the same data set: the damage it presents. We can, therefore, also document the geometry of the object by making a survey of the damage it presents at the moment of data collection. The cracks and their layout and trajectory can be observed, allowing measurements to be made to assess necessary conservation measures. Given that the apertures of the same crack at different points in historical structures often vary by several centimeters, it is also important to know the extent of the damage along its entire path, and whether there is any relative motion between the two sides of the crack. This communication presents the application of laser scanning in the Alcántara Bridge and Coria Cathedral, both in the province of Cáceres (Spain). It outlines the criteria used for scanning both monuments: selection of placements, recording technique, errors between placements and the elimination of residual points. Once the mesh had been obtained, the information on the damage presented by these monuments was analysed, describing, characterizing and contrasting them with data taken in the field.

De Matías, J.; Berenguer, F.; Cortés, J. P.; De Sanjosé, J. J.; Atkinson, A.

2013-02-01

58

The Cathedral of St. Giorgio in Ragusa Ibla (Italy): a case study of the use of protective products  

NASA Astrophysics Data System (ADS)

The Cathedral of St. Giorgio in Ragusa Ibla like the majority of historic buildings in the Ragusa area is constructed mainly from locally outcropping calcarenite belonging to the Ragusa Formation. Through the years, the cathedral has undergone diverse restoration procedures using different protective products , the nature of which was determined by means of Fourier transform infrared spectroscopy (FT-IR) and gas chromatography coupled with mass spectrometry (GC MS). Regardless of these interventions, the materials used today are still subject to diverse forms of alterations and degradation (alveolitation, differential degradation, decohesions, chromatic alterations and the formation of biological patinas correlated to lichen activity), which cause considerable damage to the façade. In this paper, three protective products were tested on the calcarenite of the Ragusa Formation taken from a quarry: a fluorurated elastomer , a fluorurated anionic polyurethane and linseed oil. The protective efficiency was determined, after undergoing UV radiation aging by means of capillary water absorption, porosimetric and colorimetric procedures. The results highlighted a good and persistent protective capability of both the elastomer and the fluorurated polyurethane, whereas, the linseed oil not only provoked strong chromatic variations but also quickly lost its hydro-repellant capacity with aging.

Barone, Germana; Campani, Elisa; Casoli, Antonella; La Russa, Mauro Francesco; Lo Giudice, Antonino; Mazzoleni, Paolo; Pezzino, Antonino

2008-06-01

59

THE PUZZLING HARMONIC BEHAVIOR OF THE CATHEDRAL QPO IN XTE J1859+226  

SciTech Connect

We present a spectral and temporal analysis of the Cathedral quasi-periodic oscillation (QPO) detected in the power density spectra of the black hole binary and microquasar XTE J1859+226, obtained using Rossi X-Ray Timing Explorer. This type of QPO has been seen on two occasions (MJDs 51574.43 and 51575.43) during the 1998 outburst of this source. It manifests as two peaks with similar amplitudes ({approx}3% and {approx}5% rms) and harmonically related centroid frequencies ({approx}3 and {approx}6 Hz). The temporal properties of these two peaks are different: the amplitude of the {approx}3-Hz feature varies, in anticorrelation with the count rate, by {approx}50%. The {approx}6-Hz feature, on the other hand, shows a slight increase ({approx}7%) in its amplitude with the count rate. The rms spectra of the two peaks are also quite different. The {approx}3-Hz feature is softer than the other one, and, although its rms amplitude increases with energy, it shows a cutoff at an energy of {approx}6 keV. The rms of the {approx}6-Hz feature increases with energies up to at least 20 keV. We also study the bicoherence b{sup 2}({mu}, {nu}) of both observations. At the diagonal position of the peaks, the values b{sup 2}({approx} 3, {approx} 3) and b{sup 2}({approx} 6, {approx} 6) are rather high and similar to those reported for type C QPOs of GRS 1915+105. In comparison with the latter source, the bicoherence of the {approx}3-Hz feature is higher than that of the other peak, which may indicate that the {approx}3-Hz feature is the fundamental QPO and the other is its first harmonic. The value of b{sup 2}({approx} 3, {approx} 6) is, however, very low and therefore indicates a behavior different from that seen in the type C QPO of GRS 1915+105. We discuss the implications of these differences in the context of a harmonic relationship between the peaks, and suggest that, rather than pure harmonics, we may see different modes of the same underlying phenomenon competing to produce QPOs at different frequencies.

Rodriguez, J. [Laboratoire AIM, UMR 7158, CEA/DSM-CNRS-Universite Paris Diderot, IRFU/SAp, F-91191 Gif-sur-Yvette (France); Varniere, P. [Laboratoire APC, UMR 7164, CNRS-Universite Paris Diderot-CEA/DSM, 10 rue Alice Domon et Leonie Duquet, 75205 Paris Cedex 13 (France)

2011-07-10

60

Fault diagnosis  

NASA Technical Reports Server (NTRS)

The objective of the research in this area of fault management is to develop and implement a decision aiding concept for diagnosing faults, especially faults 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 fault monitor. Based on these abnormal sensor readings, the diagnosis concept identifies the cause or source of the fault and all components affected by the fault. 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 fault propagation as the faulted system continues to operate, and to diagnose physical damage. Draphys also reasons about behavior of the faulted system over time, to eliminate possibilities as more information becomes available, and to update the system status as more components are affected by the fault. 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 fault situations to be more complex if they involved multiple subsystems. Another was pilots could identify the faulted systems more quickly if the system status was presented in pictorial or text format. Another study is currently under way to examine pilot mental models of the aircraft subsystems and their use in diagnosis tasks. Future research plans include piloted simulation evaluation of the diagnosis decision aiding concepts and crew interface issues. Information is given in viewgraph form.

Abbott, Kathy

1990-01-01

61

Rapid exhumation at ~ 8 Ma on the Liupan Shan thrust fault from apatite fission-track thermochronology: Implications for growth of the northeastern Tibetan Plateau margin  

Microsoft Academic Search

The Liupan Shan Mountain is one of the outermost ranges in northeastern Tibetan Plateau. The onset of its uplift provides insight on whether the plateau grew sequentially outward or broad areas of the plateau deformed simultaneously. The apatite fission-track method can be used to date rapid cooling as the result of unroofing of rocks in response to tectonically induced vertical

Dewen Zheng; Pei-Zhen Zhang; Jinlin Wan; Daoyang Yuan; Chuanyou Li; Gongming Yin; Guangliang Zhang; Zhicai Wang; Wei Min; Jie Chen

2006-01-01

62

New geomorphic evidence for en échelon fault system in East Karakoram - Jiali Fault zone  

NASA Astrophysics Data System (ADS)

The Karakoram-Jiali Fault zone (KJFZ) is one of the important active fault systems in the Tibetan Plateau. This zone mainly consists of two major faults (i.e., Karakoram fault and Jiali fault) and other minor faults in between. In the middle of KJFZ, there are several en échelon minor faults, such as the faults of Beng Co, Gyaring Co, Lamu Co, and Awong Co. Those faults are all right-lateral strike-slip faults and striking N120°- 130°E. In the east of the Beng Co fault and Jiali Fault, there are still several lineations striking parallel to the Beng Co fault. They are located at 31-32°N, en échelon in configuration, similar in length, and subparallel to each other. In this study they are tentatively regarded as part of the KJFZ. Based on Landsat7 and ASTER satellite imagery, we find a number of geomorphic features to interpret them as active faults. One of above-mentioned minor faults located in the immediate west is identified with the offset of the last glacial moraine, many abandon channels, disrupted stream beds, and shutter ridges, etc. Based on a previously published TL date, the slip rate of this fault is ca. 15 ± 2 mm/yr. According to previous study, the Jiali Fault possesses rapid dextral slip rate (15-20mm/yr) and the maximum observed offset is ca. 1.5km. Both of our imagery analysis and field survey found no evidence to indicate the late Pleistocene activity of the main trace of the Jiali fault. We therefore incline to conclude that instead of the main Jiali Fault those en échelon faults in its west are relatively more active at least since late Pleistocene.

Chung, L.; Chen, Y.; Yu, T.; Cao, Z.; Yin, G.

2008-12-01

63

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

64

Fault simulation using small fault samples  

Microsoft Academic Search

This article emphasizes simulation-based sampling techniques for estimating fault coverage that use small fault samples. Although random testing is considered to be the primary area of application of the technique it is also suitable for estimating the fault coverage of nonrandom tests based on specific fault models. Especially for fault coverages exceeding 95%, it is shown that a precise estimate

Wilfried Daehn

1991-01-01

65

Physiochemical Evidence of Faulting Processes and Modeling of Fluid in Evolving Fault Systems in Southern California  

SciTech Connect

Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.

Boles, James [Professor

2013-05-24

66

Fault models  

NASA Technical Reports Server (NTRS)

A major problem in the qualification of integrated circuit cells and in the development of adequate tests for the circuits is to lack of information on the nature and density of fault models. Some of this information is being obtained from the test structures. In particular, the Pinhole Array Capacitor is providing values for the resistance of gate oxide shorts, and the Addressable Inverter Matrix is providing values for parameter distributions such as noise margins. Another CMOS fault mode, that of the open-gated transistor, is examined and the state of the transistors assessed. Preliminary results are described for a number of open-gated structures such as transistors, inverters, and NAND gates. Resistor faults are applied to various CMOS gates and the time responses are noted. The critical value for the resistive short to upset the gate response was determined.

Sayah, H. R.; Buehler, M. G.

1985-01-01

67

Synthetic consolidants attacked by melanin-producing fungi: case study of the biodeterioration of Milan (Italy) cathedral marble treated with acrylics.  

PubMed

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks. PMID:17071788

Cappitelli, Francesca; Nosanchuk, Joshua D; Casadevall, Arturo; Toniolo, Lucia; Brusetti, Lorenzo; Florio, Sofia; Principi, Pamela; Borin, Sara; Sorlini, Claudia

2007-01-01

68

Synthetic Consolidants Attacked by Melanin-Producing Fungi: Case Study of the Biodeterioration of Milan (Italy) Cathedral Marble Treated with Acrylics?  

PubMed Central

Monuments and artistic stone surfaces are often consolidated and protected with synthetic polymers, in particular, acrylics. Although it is generally thought that acrylic polymers are resistant to biodeterioration, we report for the first time the systematic occurrence of dematiaceous meristematic fungi on many marble samples of the cathedral in Milan (Italy) previously treated with this material. Fourier transform infrared spectroscopy applied to the Milan cathedral stone samples revealed characteristic features of biodeteriorated synthetic resins that differentiated them from the aged but nonbiodeteriorated samples. Samples showing biological colonization were analyzed for the presence of fungi. Cultivation and morphological characterization and methods independent from cultivation, such as denaturing gradient gel electrophoresis coupled with partial 18S rRNA gene sequencing and immunofluorescence staining with melanin-binding antibodies, showed that melanin-producing species are heavily present on stone surfaces protected with acrylic resins. This observation raises the question of the effectiveness of acrylics in protecting stone artworks.

Cappitelli, Francesca; Nosanchuk, Joshua D.; Casadevall, Arturo; Toniolo, Lucia; Brusetti, Lorenzo; Florio, Sofia; Principi, Pamela; Borin, Sara; Sorlini, Claudia

2007-01-01

69

Case-Based Diagnosis of Multiple Faults  

Microsoft Academic Search

In order to maintain complex technical systems e.g. a telecommunication network, a rapid and precise recognition of faults and critical situations is required. But the large number of different components, the high degree of interdependencies among the components and the permanent changes in these systems make the diagnosis of faults and critical situations difficult.

Ralph Deters; Bundeswehr Mianchen

1995-01-01

70

Detection and elimination of cyanobacteria from frescoes: the case of the St. Brizio Chapel (Orvieto Cathedral, Italy).  

PubMed

A rosy discoloration partly masking the Luca Signorelli frescoes in St. Brizio Chapel (Orvieto Cathedral, Italy) for many years proved to be a biological alteration, so the present research focused on investigating biodeteriogens and selecting an appropriate biocide to treat them. Optical epifluorescence and electronic microscopic observations of the rosy powder revealed a prevalent autofluorescent coccoid form with a diameter bigger than 5 microm. Chlorophylls a and b were extracted, suggesting the presence of cyanobacteria, a thesis subsequently confirmed by flow cytometry. Cultural media were inoculated with the rosy powder, and microorganisms grew as a green patina in phototrophic conditions and as a rosy patina when organic compounds were added to the mineral medium. The rosy discoloration was most likely caused by the presence of phycoerythrin. The sequencing of the cyanobacteria-specific polymerase chain reaction (PCR)-DGGE bands matched, with a similarity percentage >94, uncultured cyanobacteria, and the sequences were deposited in the GenBank under EU874241, EU874242, EU874243, EU874244, EU874245, EU874246, and EU874247. Finally, the efficiency of the two biocides Neo Desogen and Metatin 5810-101, both based on benzalkonium chloride, was evaluated using adenosine triphosphate measurements and PCR-based detection of cyanobacteria. Metatin, used in situ at 2% of the trade product, proved to be the better biocide, no cyanobacteria being detected after the Metatin treatment. PMID:18752018

Cappitelli, F; Abbruscato, P; Foladori, P; Zanardini, E; Ranalli, G; Principi, P; Villa, F; Polo, A; Sorlini, C

2009-05-01

71

Advanced information system for the investigation of the deterioration of the floor in the Cathedral of Siena  

NASA Astrophysics Data System (ADS)

The preservation and recovery of monuments are hotly debated topics in the field of cultural heritage conservation. In the early 1990's, our group in Siena started a study of the stone materials used in the architecture of Siena. The data were then processed by a GIS (Geographic Information System), which allows one to perform a series of interactive data analyses. An important example of the application of this methodology is the marble floor of the cathedral of Siena, consisting of 58 main scenes framed by decorations, for a total of 2500 m2. The analysis involved: a petrographic study of the main lithotypes used in the scenes and of the various types of deterioration detected; realization of a full digital photo-image and of digital models for the reliefs; identification of anomalies beneath the floor by means of geo-radar and geo-electric instruments; monitoring of thermohygrometric conditions; mapping of the 22 stone varieties employed, their state of preservation (33 types of deterioration) and the previous restoration interventions.

Giamello, Marco; Droghini, Francesca; Guasparri, Giovanni; Mugnaini, Sonia; Romussi, Walter; Sabatini, Giuseppe; Scala, Andrea

2003-10-01

72

Determining the impact of faulting on the rate of erosion in a low-relief landscape: A case study using in situ produced 21Ne on active normal faults in the Bishop  

Microsoft Academic Search

article i nfo 21 Ne Normal faults exposed in the Volcanic Tableland in the southeastern part of the Bishop Tuff provide a unique opportunity to investigate whether tectonic faulting and associated fracturing control the rate of erosion in the vicinity of actively growing faults. If fracturing increases with fault displacement, erosion close to the faults should be more rapid for

California M. M. Goethals; S. Niedermann; R. Hetzel; C. R. Fenton

73

Microprocessor entomology: a taxonomy of design faults in COTS microprocessors  

Microsoft Academic Search

The rapid increase of the complexity of high-performance COTS (Commercial Off-The-Shelf) microprocessors has led to continuing post-design discoveries of numerous design faults, called “errata” by the manufacturers. This paper presents a systematic framework, the Design Fault Taxonomy, for the study of such design faults. Based on the proposed methodology, an in-depth analysis of design faults uncovered in the Intel Pentium

Algirdas Avizienis; Yutao He

1999-01-01

74

CMOS Bridging Fault Detection  

Microsoft Academic Search

The authors compare the performance of two test generation techniques, stuck fault testing and current testing, when applied to CMOS bridging faults. Accurate simulation of such faults mandated the development of several new design automation tools, including an analog-digital fault simulator. The results of this simulation are analyzed. It is shown that stuck fault test generation, while inherently incapable of

Thomas M. Storey; Wojciech Maly

1990-01-01

75

Normal Fault Visualization  

NSDL National Science Digital Library

This module demonstrates the motion on an active normal fault. Faulting offsets three horizontal strata. At the end of the faulting event, surface topography has been generated. The upper rock layer is eroded by clicking on the 'begin erosion' button. The operator can manipulate the faulting motion, stopping and reversing motion on the fault at any point along the transit of faulting. The action of erosion is also interactive. One possible activity is an investigation of the control of different faulting styles on regional landscape form. This visual lends itself to an investigation of fault motion, and a comparison of types of faults. The interactive normal faulting visual could be compared to other interactive visuals depicting thrust faults, reverse faults, and strike slip faults (interactive animations of these fault types can be found by clicking on 'Media Types' at top red bar, then 'Animations', then 'Faults'). By comparing the interactive images of different types of faulting with maps of terrains dominated by different faulting styles, students are aided in conceptualizing how certain faulting styles produce distinctive landforms on the earth's surface (e.g., ridge and valley topography [thrust faulting dominant] versus basin-and-range topography [normal faulting dominant]). Jimm Myers, geology professor at the University of Wyoming, originated the concept of The Magma Foundry, a website dedicated to improving Earth science education across the grade levels. The Magma Foundry designs and creates modular, stand-alone media components that can be utilized in a variety of pedagogical functions in courses and labs.

Myers, Jimm

76

Segmentation and growth of an obliquely reactivated normal fault  

NASA Astrophysics Data System (ADS)

Detailed kinematic analysis of a large (1800 m maximum displacement) reactivated normal fault in the Taranaki Basin, New Zealand, has been conducted using high quality 3D seismic data. The Parihaka Fault is approximately north-south striking in basement, where it accrued Late Cretaceous to Early Eocene displacements in response to east-west extension, and was obliquely reactivated by NW-SE extension in the Pliocene. Reactivation resulted in upward propagation, newly formed segmentation and up-dip clockwise rotation of the fault surface by up to ˜20° from the strike of the basement fault. Fault segmentation, and map-view soft-linkage by relay zones in post Miocene strata, was synchronous with the formation of antithetic faults in Late Miocene strata at bends in the fault surface. Fault segment lengths, antithetic faults and relay zone dimensions were formed geologically instantaneously during initial reactivation of the main fault at 3.7-3.4 Ma (i.e. within the first ˜10% of faulting). Rapid formation of Pliocene fault segments is followed by displacement accumulation without an increase in fault segment length until eventual relay breaching when continued ramp rotation is unsustainable. This evolutionary history is consistent with a model in which arrays of fault segments are, from inception, components of a single coherent structure.

Giba, M.; Walsh, J. J.; Nicol, A.

2012-06-01

77

Fault architecture, fault rocks and fault rock properties in carbonate rocks  

Microsoft Academic Search

Fault architecture, fault rocks and fault rock properties in carbonate rocks The current study addresses a comparative analysis of fault zones in limestone and dolomite rocks comparing the architecture of fault core and damage zones, fault rocks, and the hydrodynamic properties of faults exposed in the Upper Triassic Wetterstein Fm. of the Hochschwab Massif (Austria). All analysed faults are sinistral

Helene Bauer; Kurt Decker

2010-01-01

78

Design of fault simulator  

Microsoft Academic Search

Fault simulator is proposed to understand and evaluate all possible fault propagation scenarios, which is an essential part of safety design and operation design and support of chemical\\/production processes. Process models are constructed and integrated with fault models, which are formulated in qualitative manner using fault semantic networks (FSN). Trend analysis techniques are used to map real time and simulation

Hossam A. Gabbar; Hanaa E. Sayed; Ajiboye S. Osunleke; Hara Masanobu

2009-01-01

79

On Distributed Fault Simulation  

Microsoft Academic Search

The authors examine the computational aspects of fault simulation of digital circuits and address issues related to the efficient partitioning of a fault simulation task to a number of subtasks assignable for execution to the nodes of a distributed system. They review the basic concepts involved in the operation of fault simulation. They describe the implementation of a distributed fault

Tassos Markas; Mark Royals; Nick Kanopoulos

1990-01-01

80

High impedance fault detection  

US Patent & Trademark Office Database

An apparatus, system, and method for detecting high impedance faults in electrical power lines using a composite high impedance fault detection system having a voter logic that samples the logical outputs from a plurality of independent high impedance detection systems and determines a high impedance fault if any two of the plurality of independent high impedance detection systems indicates a high impedance fault. Preferably, the plurality of high impedance detection systems include a wavelet based high impedance fault detection system having a first logical output, a higher order statistics based high impedance fault detection system having a second logical output, and a neural net based high impedance fault detection system having a third logical output. Preferably, each of the plurality of high impedance fault detection systems includes an independent high impedance fault detection application that independently detects a high impedance fault on the electrical power line.

2006-06-27

81

Fault analysis based on fault reporting in JSP software development  

Microsoft Academic Search

A fault analysis procedure is proposed for software development using JSP (Jackson structured programming). In the procedure, it is assumed that developers submit a fault report, which includes information (such as fault type, cause of fault and product) on actual fault correction activities. The procedure can identify the step in the JSP process at which fault might be introduced. Fault

Yukio MOHRI; T. Kikuno

1991-01-01

82

Towards In-Flight Detection and Accommodation of Faults in Aircraft Engines  

Microsoft Academic Search

To effectively accommodate safety critical faults in-flight it is necessary to rapidly detect them and to have a means to accommodate the fault. We present results on model-based fault detection using sensor residuals from an extended Kalman filter with an embedded real-time engine model to characterize un-faulted behavior over the flight envelope. Thereafter, we present an approach for online fault

Randal Rausch; Daniel E. Viassolo; Aditya Kumar; Kai Goebel; Neil Eklund; Brent Brunell; Pierino Bonanni

2004-01-01

83

Loading of the san andreas fault by flood-induced rupture of faults beneath the salton Sea  

USGS Publications Warehouse

The southern San Andreas fault has not experienced a large earthquake for approximately 300 years, yet the previous five earthquakes occurred at ???180-year intervals. Large strike-slip faults are often segmented by lateral stepover zones. A Movement on smaller faults within a stepover zone could perturb the main fault segments and potentially trigger a large earthquake. The southern San Andreas fault terminates in an extensional stepover zone beneath the Salton Sea-a lake that has experienced periodic flooding and desiccation since the late Holocene. Here we reconstruct the magnitude and timing of fault activity beneath the Salton Sea over several earthquake cycles. We observe coincident timing between flooding events, stepover fault displacement and ruptures on the San Andreas fault. Using Coulomb stress models, we show that the combined effect of lake loading, stepover fault movement and increased pore pressure could increase stress on the southern San Andreas fault to levels sufficient to induce failure. We conclude that rupture of the stepover faults, caused by periodic flooding of the palaeo-Salton Sea and by tectonic forcing, had the potential to trigger earthquake rupture on the southern San Andreas fault. Extensional stepover zones are highly susceptible to rapid stress loading and thus the Salton Sea may be a nucleation point for large ruptures on the southern San Andreas fault. ?? 2011 Macmillan Publishers Limited. All rights reserved.

Brothers, D.; Kilb, D.; Luttrell, K.; Driscoll, N.; Kent, G.

2011-01-01

84

Behavioral Fault Simulation in VHDL  

Microsoft Academic Search

This paper presents two tools which facilitate the fault simulation of behavioral models described using VHDL. The first tool is the Behavioral Fault Mapper (BFM). The BFM algorithm accepts a fault-free VHDL model and a fault list of N faults from which it produces N faulty models. The process of mapping the faults in the fault list onto copies of

P. C. Ward; James R. Armstrong

1990-01-01

85

Fault Tolerant Strategies for BLDC Motor Drives under Switch Faults  

Microsoft Academic Search

In this paper, the fault tolerant system for BLDC motors has been proposed to maintain the control performance under switching device faults of inverter. The proposed fault tolerant system provides compensation for open-circuit faults and short-circuit faults in power converter. The fault identification is quickly achieved by simple algorithm using the characteristic of BLDC motor drives. The drive system after

Byoung-Gun Park; Tae-Sung Kim; Ji-Su Ryu; Dong-Seok Hyun

2006-01-01

86

Bridge fault diagnosis using stuck-at fault simulation  

Microsoft Academic Search

A new diagnostic fault simulator is described that diagnoses both feedback and nonfeedback bridge faults in combinational circuits while using information from fault simulation of single stuck-at faults. A realistic fault model is used which considers the existence of the Byzantine Generals problem. Sets representing nodes possibly involved in a defect are partitioned based on logic and fault simulation of

Jue Wu; Elizabeth M. Rudnick

2000-01-01

87

Fault Mapping in Haiti  

USGS Multimedia Gallery

USGS geologist Carol Prentice surveying features that have been displaced by young movements on the Enriquillo fault in southwest Haiti.  The January 2010 Haiti earthquake was associated with the Enriquillo fault....

2010-08-13

88

Nonlinear Fault Diagnosis.  

National Technical Information Service (NTIS)

A summary of several research projects in the nonlinear fault diagnosis is given. Several alternative algorithms for the solution of the nonlinear fault diagnosis problem are presented, together with a diagnosibility theory, and a set of criteria which an...

R. W. Liu K. Nakajima P. Olivier Q. D. Ngo R. Saeks

1981-01-01

89

Off-fault damage and acoustic emission distributions during the evolution of structurally complex faults over series of stick-slip events  

NASA Astrophysics Data System (ADS)

Variations in fault structure, for example, surface roughness and deformation zone width, influence the location and dynamics of large earthquakes as well as the distribution of small seismic events. In nature, changes in fault roughness and seismicity characteristics can rarely be studied simultaneously, so that little is known about their interaction and evolution. Here, we investigate the connection between fault structure and near-fault distributions of seismic events over series of stick-slip cycles in the laboratory. We conducted a set of experiments on rough faults that developed from incipient fracture surfaces. We monitored stress and seismic activity which occurred in the form of acoustic emissions (AEs). We determined AE density distributions as a function of fault normal distance based on high-accuracy hypocentre locations during subsequent interslip periods. The characteristics of these distributions were closely connected to different structural units of the faults, that is, the fault core, off-fault and background damage zone. The core deformation zone was characterized by consistently high seismic activity, whereas the off-fault damage zone displayed a power-law decay of seismic activity with increasing distance from the fault core. The exponents of the power-law-distributed off-fault activity increased with successive stick-slip events so that later interslip periods showed a more rapid spatial decay of seismic activity from the fault. The increase in exponents was strongest during the first one to three interslip periods and reached approximately constant values thereafter. The relatively rapid spatial decay of AE events during later interslip periods is likely an expression of decreasing fault zone complexity and roughness. Our results indicate a close relationship between fault structure, stress and seismic off-fault activity. A more extensive mapping of seismic off-fault activity-decay has the potential to significantly advance the understanding of fault zone properties including variations in fault roughness and stress.

Goebel, T. H. W.; Becker, T. W.; Sammis, C. G.; Dresen, G.; Schorlemmer, D.

2014-06-01

90

Off-fault damage and acoustic emission distributions during the evolution of structurally complex faults over series of stick-slip events  

NASA Astrophysics Data System (ADS)

Variations in fault structure, for example, surface roughness and deformation zone width, influence the location and dynamics of large earthquakes as well as the distribution of small seismic events. In nature, changes in fault roughness and seismicity characteristics can rarely be studied simultaneously, so that little is known about their interaction and evolution. Here, we investigate the connection between fault structure and near-fault distributions of seismic events over series of stick-slip cycles in the laboratory. We conducted a set of experiments on rough faults that developed from incipient fracture surfaces. We monitored stress and seismic activity which occurred in the form of acoustic emissions (AEs). We determined AE density distributions as a function of fault normal distance based on high-accuracy hypocentre locations during subsequent interslip periods. The characteristics of these distributions were closely connected to different structural units of the faults, that is, the fault core, off-fault and background damage zone. The core deformation zone was characterized by consistently high seismic activity, whereas the off-fault damage zone displayed a power-law decay of seismic activity with increasing distance from the fault core. The exponents of the power-law-distributed off-fault activity increased with successive stick-slip events so that later interslip periods showed a more rapid spatial decay of seismic activity from the fault. The increase in exponents was strongest during the first one to three interslip periods and reached approximately constant values thereafter. The relatively rapid spatial decay of AE events during later interslip periods is likely an expression of decreasing fault zone complexity and roughness. Our results indicate a close relationship between fault structure, stress and seismic off-fault activity. A more extensive mapping of seismic off-fault activity-decay has the potential to significantly advance the understanding of fault zone properties including variations in fault roughness and stress.

Goebel, T. H. W.; Becker, T. W.; Sammis, C. G.; Dresen, G.; Schorlemmer, D.

2014-04-01

91

The influence of indoor microclimate on thermal comfort and conservation of artworks: the case study of the cathedral of Matera (South Italy)  

NASA Astrophysics Data System (ADS)

The Matera Cathedral was built in Apulian-Romanesque style in the thirteenth century on the highest spur of the "Civita" that divides "Sassi" district in two parts. The constructive material is the calcareous stone of the Vaglia, extracted from quarries in the area of Matera. The interior is Baroque and presents several artworks, including: mortars covered with a golden patina, a wooden ceiling, painted canvas and painting frescoes, three minor altars and a major altar of precious white marble, a nativity scene made of local painted limestone. The research had to evaluate the indoor microclimate during and after the restoration works, that also concern the installation of floor heating system to heat the indoor environments. Specifically, we have analyzed the thermal comfort and the effect that the artwork and construction materials inside the Cathedral of Matera have undergone. This evaluation was carried out in two different phases: in the first one we have investigated the state of the art (history of the site, constructive typology and artworks); in the second one we have done a systematic diagnosis and an instrumental one. The analysis were carried out in a qualitative and quantitative way and have allowed us to test indoor microclimatic parameters (air temperature, relative humidity and indoor air velocity), surface temperatures of the envelope and also Fanger's comfort indices (PMV and PPD) according to the UNI EN ISO 7730. The thermal mapping of the wall surface and of the artworks, carried out through thermal imaging camera, and the instrumental measurement campaigns were made both before restoration and after installation of the heating system; in addition measurements were taken with system on and off. The analysis thus made possible to verify that the thermo-hygrometric parameters found, as a result of the recovery operations, meet the limits indicated by the regulations and international studies. In this way, we can affirm that the indoor environment of the Cathedral of Matera is suitable both from the point of view of indoor comfort (both during the summer and the winter season) and of microclimatic parameters that are in the intervals prescribed by the regulations on the conservation of artworks of art (Ministerial Decree of 10/05/2001 dictated by the Ministry for heritage and cultural activities). Moreover the energy performance of the building-plant system was evaluated according to the Italian Norm UNI TS 11300. In particular the summer comfort is guaranteed by the huge thermal inertia of the structure that reduces the internal temperature fluctuation. Instead, the winter comfort is guaranteed by the floor heating system, which through the use of evolving fluid at low temperatures, also ensures higher efficiency and significant energy savings, as well as the protection and conservation of the artistic heritage present in the Cathedral.

Cardinale, Tiziana; Rospi, Gianluca; Cardinale, Nicola; Paterino, Lucia; Persia, Ivan

2014-05-01

92

Fault recovery characteristics of the fault tolerant multi-processor  

NASA Technical Reports Server (NTRS)

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.

Padilla, Peter A.

1990-01-01

93

The San Andreas Fault  

USGS Publications Warehouse

The presence of the San Andreas fault was brought dramatically to world attention on April 18, 1906, when sudden displacement along the fault produced the great San Francisco earthquake and fire. This earthquake, however, was but one of many that have resulted from episodic displacement along the fault throughout its life of about 15-20 million years.

Schulz, Sandra S.; Wallace, Robert E.

1993-01-01

94

Fault tolerant control of spacecraft  

NASA Astrophysics Data System (ADS)

Autonomous multiple spacecraft formation flying space missions demand the development of reliable control systems to ensure rapid, accurate, and effective response to various attitude and formation reconfiguration commands. Keeping in mind the complexities involved in the technology development to enable spacecraft formation flying, this thesis presents the development and validation of a fault tolerant control algorithm that augments the AOCS on-board a spacecraft to ensure that these challenging formation flying missions will fly successfully. Taking inspiration from the existing theory of nonlinear control, a fault-tolerant control system for the RyePicoSat missions is designed to cope with actuator faults whilst maintaining the desirable degree of overall stability and performance. Autonomous fault tolerant adaptive control scheme for spacecraft equipped with redundant actuators and robust control of spacecraft in underactuated configuration, represent the two central themes of this thesis. The developed algorithms are validated using a hardware-in-the-loop simulation. A reaction wheel testbed is used to validate the proposed fault tolerant attitude control scheme. A spacecraft formation flying experimental testbed is used to verify the performance of the proposed robust control scheme for underactuated spacecraft configurations. The proposed underactuated formation flying concept leads to more than 60% savings in fuel consumption when compared to a fully actuated spacecraft formation configuration. We also developed a novel attitude control methodology that requires only a single thruster to stabilize three axis attitude and angular velocity components of a spacecraft. Numerical simulations and hardware-in-the-loop experimental results along with rigorous analytical stability analysis shows that the proposed methodology will greatly enhance the reliability of the spacecraft, while allowing for potentially significant overall mission cost reduction.

Godard

95

Application of multiclass support vector machines for fault diagnosis of field air defense gun  

Microsoft Academic Search

This paper introduces multiclass support vector machines (SVM) and a back-propagation neural network (BPNN) for fault diagnosis of a field air defense gun. These intelligent methods preclude human error in fault diagnosis, and they make it possible to diagnose a new failure precisely and rapidly. Our experimental results show that both SVM and BPNN provide excellent fault diagnosis accuracy when

S. Deng; Seng-Yi Lin; We-Luan Chang

2011-01-01

96

Diagnosing CMOS bridging faults with stuck-at fault dictionaries  

Microsoft Academic Search

It is shown that the traditional approach to diagnosing stuck-at faults with fault dictionaries generated for stuck-at faults is not appropriate for diagnosing CMOS bridging faults. A novel technique for using stuck-at-fault dictionaries to diagnose bridging faults is described. Teradyne's LASAR was used to simulate bridging and stuck-at faults in a number of combinational circuits, including parity trees, multiplexers, and

Steven D. Millman; Edward J. McCluskey; John M. Acken

1990-01-01

97

Rough faults, distributed weakening, and off-fault deformation  

Microsoft Academic Search

We report systematic spatial variations in fault rocks along nonplanar strike-slip faults cross-cutting the Lake Edison Granodiorite, Sierra Nevada, California (Sierran wavy fault) and Lobbia outcrops of the Adamello Batholith in the Italian Alps (Lobbia wavy fault). In the case of the Sierran fault, pseudotachylyte formed at contractional fault bends, where it is found as thin (1–2 mm) fault-parallel veins.

W. Ashley Griffith; Stefan Nielsen; Giulio Di Toro; Steven A. F. Smith

2010-01-01

98

Accelerated Fault Simulation and Fault Grading in Combinational Circuits  

Microsoft Academic Search

The principles of fault simulation and fault grading are introduced by a general description of the problem. Based upon the well-known concept of restricting fault simulation to the fanout stems and of combining it with a backward traversal inside the fanout-free regions of the circuit, proposals are presented to further accelerate fault simulation and fault grading. These proposals aim at

Kurt Antreich; Michael H. Schulz

1987-01-01

99

On the Emulation of Software Faults by Software Fault Injection  

Microsoft Academic Search

This paper presents an experimental study on the emulation of software faults by fault injection. In a first experiment, a set of real software faults has been compared with faults injected by a SWIFI tool (Xception) to evaluate the accuracy of the injected faults. Results revealed the limitations of Xception (and other SWIFI tools) in the emulation of different classes

Henrique Madeira; Diamantino Costa; Marco Vieira

2000-01-01

100

Frictional constraints on crustal faulting  

USGS Publications Warehouse

We consider how variations in fault frictional properties affect the phenomenology of earthquake faulting. In particular, we propose that lateral variations in fault friction produce the marked heterogeneity of slip observed in large earthquakes. We model these variations using a rate- and state-dependent friction law, where we differentiate velocity-weakening behavior into two fields: the strong seismic field is very velocity weakening and the weak seismic field is slightly velocity weakening. Similarly, we differentiate velocity-strengthening behavior into two fields: the compliant field is slightly velocity strengthening and the viscous field is very velocity strengthening. The strong seismic field comprises the seismic slip concentrations, or asperities. The two "intermediate" fields, weak seismic and compliant, have frictional velocity dependences that are close to velocity neutral: these fields modulate both the tectonic loading and the dynamic rupture process. During the interseismic period, the weak seismic and compliant regions slip aseismically, while the strong seismic regions remain locked, evolving into stress concentrations that fail only in main shocks. The weak seismic areas exhibit most of the interseismic activity and aftershocks but can also creep seismically. This "mixed" frictional behavior can be obtained from a sufficiently heterogenous distribution of the critical slip distance. The model also provides a mechanism for rupture arrest: dynamic rupture fronts decelerate as they penetrate into unloaded complaint or weak seismic areas, producing broad areas of accelerated afterslip. Aftershocks occur on both the weak seismic and compliant areas around a fault, but most of the stress is diffused through aseismic slip. Rapid afterslip on these peripheral areas can also produce aftershocks within the main shock rupture area by reloading weak fault areas that slipped in the main shock and then healed. We test this frictional model by comparing the seismicity and the coseismic slip for the 1966 Parkfield, 1979 Coyote Lake, and 1984 Morgan Hill earthquakes. The interevent seismicity and aftershocks appear to occur on fault areas outside the regions of significant slip: these regions are interpreted as either weak seismic or compliant, depending on whether or not they manifest interevent seismicity.

Boatwright, J.; Cocco, M.

1996-01-01

101

It's Not Your Fault  

NSDL National Science Digital Library

In this lesson students will learn about tectonic plate movement. They will discover that we can measure the relative motions of the Pacific Plate and the North American Plate along the San Andreas Fault. Students will be able to compare and contrast movements on either side of the San Andreas Fault, calculate the amount of movement of a tectonic plate over a period of time, and describe the processes involved in the occurrence of earthquakes along the fault.

102

Complex Paleotopography and Faulting near the Elsinore Fault, Coyote Mountains, southern California  

NASA Astrophysics Data System (ADS)

The Coyote Mountains of southern California are bounded on the southwest by the Elsinore Fault, an active dextral fault within the San Andreas Fault zone. According to Axen and Fletcher (1998) and Dorsey and others (2011), rocks exposed in these mountains comprise a portion of the hanging wall of the east-vergent Salton Detachment Fault, which was active from the late Miocene-early Pliocene to Ca. 1.1-1.3 Ma. Detachment faulting was accompanied by subsidence, resulting in deposition of a thick sequence of marine and nonmarine sedimentary rocks. Regional detachment faulting and subsidence ceased with the inception of the Elsinore Fault, which has induced uplift of the Coyote Mountains. Detailed geologic mapping in the central Coyote Mountains supports the above interpretation and adds some intriguing details. New discoveries include a buttress unconformity at the base of the Miocene/Pliocene section that locally cuts across strata at an angle so high that it could be misinterpreted as a fault. We thus conclude that the syn-extension strata were deposited on a surface with very rugged topography. We also discovered that locally-derived nonmarine gravel deposits exposed near the crest of the range, previously interpreted as part of the Miocene Split Mountain Group by Winker and Kidwell (1996), unconformably overlie units of the marine Miocene/Pliocene Imperial Group and must therefore be Pliocene or younger. The presence of such young gravel deposits on the crest of the range provides evidence for its rapid uplift. Additional new discoveries flesh out details of the structural history of the range. We mapped just two normal faults, both of which were relatively minor, thus supporting Axen and Fletcher's assertion that the hanging wall block of the Salton Detachment Fault had not undergone significant internal deformation during extension. We found abundant complex synthetic and antithetic strike-slip faults throughout the area, some of which offset Quaternary alluvial deposits. We interpret these faults as Riedel shears of the Elsinore Fault that distribute dextral strain over an area at least 2 km wide. Finally, our mapping of the Elsinore Fault itself reveals two releasing bends that are superimposed on the overall transpressive regime in the area. Axen, G.J. and Fletcher, J.M., 1998, Hall Volume, GSA, p. 365-392. Dorsey, R.J., Housen, B.A., Janecke, S.U., Fanning, C. M., Spears, A.L.F., 2011, GSA Bulletin, v. 123, p. 771-793. Winker, C.D. and Kidwell, S.M., 1996, Field Conference Guide, Pacific Section AAPG/SEPM, Book 80, p. 295-336.

Brenneman, M. J.; Bykerk-Kauffman, A.

2012-12-01

103

How Faults Shape the Earth.  

ERIC Educational Resources Information Center

Presents fault activity with an emphasis on earthquakes and changes in continent shapes. Identifies three types of fault movement: normal, reverse, and strike faults. Discusses the seismic gap theory, plate tectonics, and the principle of superposition. Vignettes portray fault movement, and the locations of the San Andreas fault and epicenters of…

Bykerk-Kauffman, Ann

1992-01-01

104

Relationship Between Mapped Fault Stepovers and Earthquake Fault Planes at Depth  

NASA Astrophysics Data System (ADS)

The San Andreas fault system in the San Francisco Bay area is complex, consisting of several sub-parallel strands with numerous stepovers and bends. Source characterization of future likely earthquakes in the Bay Area requires understanding of the role these fault stepovers and bends play in fault segmentation. Absent aftershocks or microseismicity, it is difficult to determine the subsurface fault geometry. To better understand the role of geometric complexity in controlling earthquake ruptures, I have examined data from several recent major strike-slip earthquakes. The 1995 Mw6.9 Kobe earthquake originated within a 5-km right (dilatational) step in a right-lateral fault and produced a bilateral rupture. Wald (J. Phys. Earth, 1996) showed that the hypocenter occurred at the intersection of the two well-constrained, offset fault planes that were steeply dipping toward each other. A 3-km right step in the San Andreas offshore from the Golden Gate inferred from seismic and potential field data consistently produces normal faulting microearthquakes. The 1906 earthquake with its bilateral rupture is thought to have originated along the offshore segment of the San Andreas fault near the Golden Gate; by analogy with the Kobe earthquake, we have suggested that the 1906 also nucleated within a stepover region. Modeling dynamic rupture propagation constrained by near-fault ground motion records for the 1999 Izmit M7.4 earthquake, led Aochi and Madariaga (BSSA, 2003) to conclude that this rupture was rapid and continuous on a smooth fault structure with a bend of only a few degrees beneath a 5-km right (dilatational) stepover mapped at the surface in the vicinity of Sapanca lake. Similarly, aftershocks and surface faulting of the1995 Mw7.2 Landers earthquake suggest continuous rupture across a 5-km dilatational jog, utilizing an oblique fault connecting the 2 offset fault segments; whereas, the rupture across a second, 2-km dilatational jog appears more diffuse, with no continuous through-going structure (Felzer and Beroza, GRL, 1999). Relocated East Bay microseismicity using the double-difference technique indicates a continuous zone consisting of straight, near-vertical fault planes connecting the Calaveras and Hayward faults across a 5-6 km left (restraining) step (Waldhauser and Ellsworth, JGR, 2002; Ponce et al., EOS, 2003; Simpson et al., EOS, 2003). These near-vertical planes are well-defined below 5 km depth, in contrast to a complex pattern of surface fault traces with no through-going, connecting structure. The data suggest that, for at least some fault stopovers, the earthquake rupture surface at depth may be far simpler and more continuous than surface fault traces suggest and that fault stepovers and bends mapped at the surface do not necessarily represent segment boundaries or major energy barriers to rupture at depth. These observations raise intriguing questions about how, absent microseismisty, to determine if a fault stepover may have a simple connection at depth and what parameters, e.g. step size, total displacement, rock type, relative fault strength, etc. might control the depth variation in structural style

Zoback, M.

2003-12-01

105

Analysis of fault traps  

SciTech Connect

Unfaulted four-way-dip closures are the simplest and most attractive hydrocarbon traps. A single sealing lithology can provide both top and lateral seals. Seal risks are minimized with unfaulted four-way-dip closures. Unfortunately, most large four-way-drip closures have already been drilled, particularly in mature areas such as the US Gulf Coast. Exceptions may exist in deep water, at great depth, or in areas with significant lateral velocity variations, but for the most part, explorationists working mature areas are looking for either fault traps or stratigraphic traps. This article focuses on extensional fault systems, although many of the observations are applicable to compressional and strike-slip faulting. The following topics are discussed: mapping faults including discussions on the aliasing problem, fault shape, 3-D data, en echelon faults and the coherence cube; a general discussion of fault traps; juxtaposition traps and the use of ``Allan sections;`` and fault-sealing traps and the three mechanisms that cause fault-zone capillary properties to differ from unfaulted rock -- clay smear, grain crushing and diagenesis.

Brenneke, J.C. [Subsurface Consultants and Associates, Inc., Houston, TX (United States)

1995-12-01

106

The Aigion–Neos Erineos coastal normal fault system (western Corinth Gulf Rift, Greece): Geomorphological signature, recent earthquake history, and evolution  

Microsoft Academic Search

At the westernmost part of the Corinth Rift (Greece), an area of rapid extension and active normal faulting, geomorphological observations reveal the existence and geometry of an active NW-SE trending coastal fault system, which includes the Aigion fault. We recognize a similar fault pattern on both the coastal range front to the NW of Aigion town and the Holocene fan

N. Palyvos; D. Pantosti; P. M. De Martini; F. Lemeille; D. Sorel; K. Pavlopoulos

2005-01-01

107

High and Low Temperature Oceanic Detachment Faults  

NASA Astrophysics Data System (ADS)

One of the most important discoveries in Plate Tectonics in the last ten years is a "detachment mode" of seafloor spreading. Up to 50% of the Atlantic seafloor has formed by a combination of magmatism and slip on long-lived, convex-up detachment faults, forming oceanic core complexes (OCC). Two end-member types of OCC can be defined: The Atlantis Bank on the Southwest Indian Ridge is a high temperature OCC sampled by ODP Hole 735b. Deformation was dominated by crystal-plastic flow both above and below the solidus at 800-950 °C, over a period of around 200 ka. In contrast, the Atlantis Massif at 30 °N in the Atlantic, sampled by IODP Hole 1309D, is a low temperature OCC in which crystal plastic deformation of gabbro is very rare and greenschist facies deformation was localised onto talc-tremolite-chlorite schists in serpentinite, and breccia zones in gabbro and diabase. The upper 100m of Hole 1309D contains about 43% diabase intruded into hydrated fault breccias. This detachment fault zone can be interpreted as a dyke-gabbro transition, which was originally (before flexural unroofing) a lateral boundary between active hydrothermal circulation in the fault zone and hangingwall, and intrusion of gabbroic magma in the footwall. Thus a major difference between high and low temperature detachment faults may be cooling of the latter by active hydrothermal circulation. 2-D thermal modelling suggests that if a detachment fault is formed in a magmatically robust segment of a slow spreading ridge, high temperature mylonites can be formed for 1-2 ka provided there is no significant hydrothermal cooling of the fault zone. In contrast, if the fault zone is held at temperatures of 400 °C by fluid circulation, cooling of the upper 1 km of the fault footwall occurs far too rapidly for extensive mylonites to form. Our models are consistent with published cooling rate data from geospeedometry and isotopic closure temperatures. The control on this process is likely a combination of geometry and timing of deformation; if the fault zone forms within a large semi-molten gabbro body it will be isolated from hydrothermal fluid, whereas if a series of small melt bodies collect in the footwall of a permeable detachment fault, they will cool rapidly. A corollary of our model is that at slow spreading ridges the depth of melt lenses and hence the dyke gabbro transition is determined not by spreading rate (as has been suggested at fast spreading ridges) but by the effective depth of high permeability and hence hydrothermal circulation. In actively faulting environments permeability can exist to greater depths, and magma can only easily rise above these depths as dykes or volcanics. The type of detachment fault formed may depend on whether detachment faults nucleate in a robust magmatic system where they can root into a melt zone, or if magma collects in the footwall of an active fault.

Titarenko, Sofya; McCaig, Andrew

2013-04-01

108

Denali Fault: Susitna Glacier  

USGS Multimedia Gallery

Helicopters and satellite phones were integral to the geologic field response. Here, Peter Haeussler is calling a seismologist to pass along the discovery of the Susitna Glacier thrust fault. View is to the north up the Susitna Glacier. The Denali fault trace lies in the background where the two lan...

2008-12-15

109

Folds and Faults  

NSDL National Science Digital Library

In this activity, students will learn how rock layers are folded and faulted and how to represent these structures in maps and cross sections. They will use playdough to represent layers of rock and make cuts in varying orientations to represent faults and other structures.

110

Fault tree handbook  

Microsoft Academic Search

This handbook describes a methodology for reliability analysis of complex systems such as those which comprise the engineered safety features of nuclear power generating stations. After an initial overview of the available system analysis approaches, the handbook focuses on a description of the deductive method known as fault tree analysis. The following aspects of fault tree analysis are covered: basic

D. F. Haasl; N. H. Roberts; W. E. Vesely; F. F. Goldberg

1981-01-01

111

Fault rocks lab  

NSDL National Science Digital Library

This lab is intended to give students some hands on experience looking at fault rocks with a suite of cataclasites and mylonites I have collected. The focus is on identifying key textural features in both hand sample and thin section and understanding how deformation within a fault zone varies with depth.

Singleton, John

112

SFT: scalable fault tolerance  

Microsoft Academic Search

In this paper we will present a new technology that we are currently developing within the SFT: Scalable Fault Tolerance FastOS project which seeks to implement fault tolerance at the operating system level. Major design goals include dynamic reallocation of resources to allow continuing execution in the presence of hardware failures, very high scalability, high efficiency (low overhead), and transparency---requiring

Fabrizio Petrini; Jarek Nieplocha; Vinod Tipparaju

2006-01-01

113

RAPID Contacts  

Cancer.gov

Rapid Access to Preventive Intervention Development (RAPID) Program Contacts Program Contact RAPID ProgramAttn: Izet M. Kapetanovic, PhD, Program Director Chemopreventive Agent Development Research Group Division of Cancer Prevention, NCI Executive Plaza

114

Solar system fault detection  

DOEpatents

A fault detecting apparatus and method are provided for use with an active solar system. The apparatus provides an indication as to whether one or more predetermined faults have occurred in the solar system. The apparatus includes a plurality of sensors, each sensor being used in determining whether a predetermined condition is present. The outputs of the sensors are combined in a pre-established manner in accordance with the kind of predetermined faults to be detected. Indicators communicate with the outputs generated by combining the sensor outputs to give the user of the solar system and the apparatus an indication as to whether a predetermined fault has occurred. Upon detection and indication of any predetermined fault, the user can take appropriate corrective action so that the overall reliability and efficiency of the active solar system are increased.

Farrington, Robert B. (Wheatridge, CO); Pruett, Jr., James C. (Lakewood, CO)

1986-01-01

115

Long-term monitoring of fresco paintings in the cathedral of Valencia (Spain) through humidity and temperature sensors in various locations for preventive conservation.  

PubMed

We describe the performance of a microclimate monitoring system that was implemented for the preventive conservation of the Renaissance frescoes in the apse vault of the Cathedral of Valencia, that were restored in 2006. This system comprises 29 relative humidity (RH) and temperature sensors: 10 of them inserted into the plaster layer supporting the fresco paintings, 10 sensors in the walls close to the frescoes and nine sensors measuring the indoor microclimate at different points of the vault. Principal component analysis was applied to RH data recorded in 2007. The analysis was repeated with data collected in 2008 and 2010. The resulting loading plots revealed that the similarities and dissimilarities among sensors were approximately maintained along the three years. A physical interpretation was provided for the first and second principal components. Interestingly, sensors recording the highest RH values correspond to zones where humidity problems are causing formation of efflorescence. Recorded data of RH and temperature are discussed according to Italian Standard UNI 10829 (1999). PMID:22164100

Zarzo, Manuel; Fernández-Navajas, Angel; García-Diego, Fernando-Juan

2011-01-01

116

Seismic and aseismic deformation associated with the 1952 Kern County, California, earthquake and relationship to the quaternary history of the White Wolf fault  

Microsoft Academic Search

Synthesis of geodetic, and seismic data from the White Wolf fault, California, indicates that the fault separates an area of late Quaternary and continuing rapid uplift in the Tehachapi Mountains and Transverse Ranges from even more rapid subsidence in the southern San Joaquin Valley. On July 21, 1952, rupture of the White Wolf fault produced the ML = 7.2 Kern

Ross S. Stein; Wayne Thatcher

1981-01-01

117

Fault weakening and earthquake instability by powder lubrication  

USGS Publications Warehouse

Earthquake instability has long been attributed to fault weakening during accelerated slip1, and a central question of earthquake physics is identifying the mechanisms that control this weakening2. Even with much experimental effort2-12, the weakening mechanisms have remained enigmatic. Here we present evidence for dynamic weakening of experimental faults that are sheared at velocities approaching earthquake slip rates. The experimental faults, which were made of room-dry, solid granite blocks, quickly wore to form a fine-grain rock powder known as gouge. At modest slip velocities of 10-60mms-1, this newly formed gouge organized itself into a thin deforming layer that reduced the fault's strength by a factor of 2-3. After slip, the gouge rapidly 'aged' and the fault regained its strength in a matter of hours to days. Therefore, only newly formed gouge can weaken the experimental faults. Dynamic gouge formation is expected to be a common and effective mechanism of earthquake instability in the brittle crust as (1) gouge always forms during fault slip5,10,12-20; (2) fault-gouge behaves similarly to industrial powder lubricants21; (3) dynamic gouge formation explains various significant earthquake properties; and (4) gouge lubricant can form for a wide range of fault configurations, compositions and temperatures15. ?? 2010 Macmillan Publishers Limited. All rights reserved.

Reches, Z.; Lockner, D. A.

2010-01-01

118

Rapid Acceleration Leads to Rapid Weakening in Earthquake-Like Laboratory Experiments  

NASA Astrophysics Data System (ADS)

After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

Chang, J. C.; Lockner, D. A.; Reches, Z.

2012-10-01

119

Rapid acceleration leads to rapid weakening in earthquake-like laboratory experiments  

USGS Publications Warehouse

After nucleation, a large earthquake propagates as an expanding rupture front along a fault. This front activates countless fault patches that slip by consuming energy stored in Earth’s crust. We simulated the slip of a fault patch by rapidly loading an experimental fault with energy stored in a spinning flywheel. The spontaneous evolution of strength, acceleration, and velocity indicates that our experiments are proxies of fault-patch behavior during earthquakes of moment magnitude (Mw) = 4 to 8. We show that seismically determined earthquake parameters (e.g., displacement, velocity, magnitude, or fracture energy) can be used to estimate the intensity of the energy release during an earthquake. Our experiments further indicate that high acceleration imposed by the earthquake’s rupture front quickens dynamic weakening by intense wear of the fault zone.

Chang, Jefferson C.; Lockner, David A; Reches, Z.

2012-01-01

120

Immunity-Based Aircraft Fault Detection System  

NASA Technical Reports Server (NTRS)

In the study reported in this paper, we have developed and applied an Artificial Immune System (AIS) algorithm for aircraft fault detection, as an extension to a previous work on intelligent flight control (IFC). Though the prior studies had established the benefits of IFC, one area of weakness that needed to be strengthened was the control dead band induced by commanding a failed surface. Since the IFC approach uses fault accommodation with no detection, the dead band, although it reduces over time due to learning, is present and causes degradation in handling qualities. If the failure can be identified, this dead band can be further A ed to ensure rapid fault accommodation and better handling qualities. The paper describes the application of an immunity-based approach that can detect a broad spectrum of known and unforeseen failures. The approach incorporates the knowledge of the normal operational behavior of the aircraft from sensory data, and probabilistically generates a set of pattern detectors that can detect any abnormalities (including faults) in the behavior pattern indicating unsafe in-flight operation. We developed a tool called MILD (Multi-level Immune Learning Detection) based on a real-valued negative selection algorithm that can generate a small number of specialized detectors (as signatures of known failure conditions) and a larger set of generalized detectors for unknown (or possible) fault conditions. Once the fault is detected and identified, an adaptive control system would use this detection information to stabilize the aircraft by utilizing available resources (control surfaces). We experimented with data sets collected under normal and various simulated failure conditions using a piloted motion-base simulation facility. The reported results are from a collection of test cases that reflect the performance of the proposed immunity-based fault detection algorithm.

Dasgupta, D.; KrishnaKumar, K.; Wong, D.; Berry, M.

2004-01-01

121

Active faults in the Kashmir Valley  

NASA Astrophysics Data System (ADS)

The risk of earthquake is ever increasing in mountains along with rapid growth of population and urbanization. Over half a million people died in the last decade due to earthquakes. The devastations of Sumatra and Thai coasts in 2004, of Kashmir and New Orleans in 2005, of SW Java in 2006, of Sumatra again in 2007, W Sichuan and Myanmar in 2008, of Haiti in 2010, Japan, New Zealand and Turkey in 2011, brought enormous damage. The primary step in this regard could be to establish an earthquake risk model. The Kashmir valley is a NW-SE trending oval-shaped inter-mountain basin. A number of low magnitude earthquakes have recently been reported from the border and few inside the Kashmir valley. A number of active reverse faults were identified in this valley using remote sensing images and active geomorphic features. NE dipping reverse faults uplifted the young alluvial fan at the SW side. An active tectonic environment has been created by these reverse faults; sediment filled streams at NE, and uplifted quaternary deposits at SW. These resulted in an overall tilting of the entire Kashmir valley towards NE. Dating of displaced deposits is required to estimate the total convergence along these faults. Broadly, these faults are because of the convergence of Indian plate beneath the Eurasian plate.

Shah, A.

2012-04-01

122

Drilling into Faults Quickly After Earthquakes (Invited)  

NASA Astrophysics Data System (ADS)

What will it take to advance from our current empirical model of earthquake initiation and fault slip, to a full physics-based understanding of the rupture process? We need to know the absolute stress levels on the fault during an earthquake, how the stresses recover afterwards to prepare for the next event, how one earthquake promotes or inhibits another, and how the material properties of a particular fault affect its propensity to fail catastrophically, rather than creep. Immediately after a large earthquake, there is an opportunity to gain crucial information to fill these gaps in knowledge. For about two years after a major earthquake, the fault is observably changing and a deep borehole can capture measurable signals. For instance, the strength of faults and their time and slip dependence are generally unknown, especially for large displacements and high slip velocity. Current laboratory evidence suggests that friction could drop dramatically during an earthquake, but the actual fault friction levels of a large earthquake have never been measured. Temperature profiles across the fault are the most direct way to quantify coseismic friction. Because most of the frictional resistance is dissipated as heat, any temperature increase on the fault at the time of the earthquake is potentially interpretable as a cumulative measure of frictional heat generation during slip. To obtain the largest and most unambiguous signal possible, it is critical to record these measurements both soon after earthquake slip, and at depths where shear stress (a function of the effective normal stress and the effective coefficient of friction) is sufficiently large to generate an observable temperature anomaly. Model calculations suggest that a borehole drilled to 2 km depth within 1.5 years after an earthquake with >1 m surface displacement should be sufficient to observe a resolvable temperature signal. Similar constraints apply for other major data needs. Combining the constraints results in a preferred timetable of drilling initiating within 6 months after the earthquake and intersect the fault at 2 km depth within 1.5 years. Although major advances in earthquake physics projects have been made from previous rapid drilling projects on the Nojima, Chelungpu and Wenchuan Faults, a hole that meets these more stringent target requirements has not yet been completed.

Brodsky, E. E.; Mori, J. J.; Fulton, P. M.

2010-12-01

123

Characterization of Fault Zones  

NASA Astrophysics Data System (ADS)

- There are currently three major competing views on the essential geometrical, mechanical, and mathematical nature of faults. The standard view is that faults are (possibly segmented and heterogeneous) Euclidean zones in a continuum solid. The continuum-Euclidean view is supported by seismic, gravity, and electromagnetic imaging studies; by successful modeling of observed seismic radiation, geodetic data, and changes in seismicity patterns; by detailed field studies of earthquake rupture zones and exhumed faults; and by recent high resolution hypocenter distributions along several faults. The second view focuses on granular aspects of fault structures and deformation fields. The granular view is supported by observations of rock particles in fault zone gouge; by studies of block rotations and the mosaic structure of the lithosphere (which includes the overall geometry of plate tectonics); by concentration of deformation signals along block boundaries; by correlation of seismicity patterns on scales several times larger than those compatible with a continuum framework; and by strongly heterogeneous wave propagation effects on the earth's surface. The third view is that faults are fractal objects with rough surfaces and branching geometry. The fractal view is supported by some statistical analysis of regional hypocenter locations; by long-range correlation of various measurements in geophysical boreholes; by the fact that observed power-law statistics of earthquakes are compatible with an underlying scale-invariant geometrical structure; by geometrical analysis of fault traces at the earth's surface; and by measurements of joint and fault surfaces topography.There are several overlaps between expected phenomenology in continuum-Euclidean, granular, and fractal frameworks of crustal deformation. As examples, highly heterogeneous seismic wavefields can be generated by granular media, by fractal structures, and by ground motion amplification around and scattering from an ensemble of Euclidean fault zones. A hierarchical granular structure may have fractal geometry. Power-law statistics of earthquakes can be generated by slip on one or more heterogeneous planar faults, by a fractal collection of faults, and by deformation of granular material. Each of the three frameworks can produce complex spatio-temporal patterns of earthquakes and faults. At present the existing data cannot distinguish unequivocally between the three different views on the nature of fault zones or determine their scale of relevance. However, in each observational category, the highest resolution results associated with mature large-displacement faults are compatible with the standard continuum-Euclidean framework. This can be explained by a positive feedback mechanism associated with strain weakening rheology and localization, which attracts the long-term evolution of faults toward progressive regularization and Euclidean geometry. A negative feedback mechanism associated with strain hardening during initial deformation phases and around persisting geometrical irregularities and conjugate sets of faults generates new fractures and granularity at different scales. We conclude that long-term deformation in the crust, including many aspects of the observed spatio-temporal complexity of earthquakes and faults, may be explained to first order within the continuum-Euclidean framework.

Ben-Zion, Y.; Sammis, C. G.

124

The Kunlun Fault  

NASA Technical Reports Server (NTRS)

The Kunlun fault is one of the gigantic strike-slip faults that bound the north side of Tibet. Left-lateral motion along the 1,500-kilometer (932-mile) length of the Kunlun has occurred uniformly for the last 40,000 years at a rate of 1.1 centimeter per year, creating a cumulative offset of more than 400 meters. In this image, two splays of the fault are clearly seen crossing from east to west. The northern fault juxtaposes sedimentary rocks of the mountains against alluvial fans. Its trace is also marked by lines of vegetation, which appear red in the image. The southern, younger fault cuts through the alluvium. A dark linear area in the center of the image is wet ground where groundwater has ponded against the fault. Measurements from the image of displacements of young streams that cross the fault show 15 to 75 meters (16 to 82 yards) of left-lateral offset. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) acquired the visible light and near infrared scene on July 20, 2000. Image courtesy NASA/GSFC/MITI/ERSDAC/JAROS, and the U.S./Japan ASTER Science Team

2002-01-01

125

Fault detection and isolation  

NASA Astrophysics Data System (ADS)

In order for a current satellite-based navigation system (such as the Global Positioning System, GPS) to meet integrity requirements, there must be a way of detecting erroneous measurements, without help from outside the system. This process is called Fault Detection and Isolation (FDI). Fault detection requires at least one redundant measurement, and can be done with a parity space algorithm. The best way around the fault isolation problem is not necessarily isolating the bad measurement, but finding a new combination of measurements which excludes it.

Bernath, Greg

1994-02-01

126

Fault detection and isolation  

NASA Technical Reports Server (NTRS)

In order for a current satellite-based navigation system (such as the Global Positioning System, GPS) to meet integrity requirements, there must be a way of detecting erroneous measurements, without help from outside the system. This process is called Fault Detection and Isolation (FDI). Fault detection requires at least one redundant measurement, and can be done with a parity space algorithm. The best way around the fault isolation problem is not necessarily isolating the bad measurement, but finding a new combination of measurements which excludes it.

Bernath, Greg

1994-01-01

127

Behavioral-level fault simulation  

Microsoft Academic Search

An approach to fault simulation is presented in which behavioral fault models represent complex failures in VLSI designs. Errors are deliberately introduced into the description of a design that contains no faults. These errors can be fault values of variables that represent state or timing parameters, a faulty description that is substituted for part of the good description, or a

SUMIT GHOSH

1988-01-01

128

VSC transmission control under faults  

Microsoft Academic Search

This paper studies the VSC (voltage source converter) transmission control for fault conditions. A small-signal VSC transmission controller considers only small deviations around steady state and in case of faults there would be large overvoltages and overcurrents. An additional fault controller is introduced to reduce transient overvoltages and overcurrents which occur in case of faults. Parallel configuration is used in

L. A. Lamont; D. Jovcic; K. Abbott

2004-01-01

129

What's Cooking? Evaluating frictional stress using extractable organic material in fault zones  

NASA Astrophysics Data System (ADS)

The detection of a frictional heating signature is a promising, but elusive, way to measure frictional stress on exhumed faults lacking evidence of melting. We present a new paleothermometer for fault zones that uses the thermal alteration of organic molecules to detect frictional heating along faults. As a rock is heated, temperature-sensitive molecules degrade, increasing the abundance of refractory organic molecules. On the short timescales involved in fault heating, these reactions are strongly temperature dependent and therefore track the maximum temperature achieved during fault slip. Furthermore, because there are no retrograde reactions in these organic systems, the maximum heating signature is preserved. We tested our approach with samples from a pseudotachylyte-bearing thrust fault in the Ghost Rocks Formation, Kodiak, Alaska and applied our approach to several strike-slip and thrust faults. In the Ghost Rocks thrust fault we found higher concentrations of refractory diamondoid compounds in the pseudotachylyte-bearing rocks and lower concentrations in adjacent fault rocks and off-fault samples. The presence of pseudotachylyte indicates significant, rapid heating of these rocks during fault slip. Our finding confirms that this rapid heating is sufficient to measurably alter the thermal maturity of organic molecules. In the other faults we studied, the concentrations of refractory methylphenanthrene molecules was no different between fault and surrounding rock indicating no detectable heating. These results suggests little frictional heating of the fault rocks occurred despite total fault offsets >20 km during burial at 2-4 km. This work represents a promising new avenue for detecting heat signatures along faults that can be applied to a variety of sedimentary rock types and burial depths.

Polissar, P. J.; Savage, H. M.; Sheppard, R. E.; Rowe, C. D.; Brodsky, E. E.

2011-12-01

130

Hoist fault diagnosis system based on optical fiber vibration sensor  

NASA Astrophysics Data System (ADS)

The mine hoist operation status is closely related to the vibration signal of the hoist various components. using optical fiber sensing technology, this paper designed a hoist fault diagnosis system based on vibration spectrum analysis. Through rapid demodulation of real-time vibration signal, the system realized vibration spectrum analysis to various parts of the hoist. The test results show that the system can achieve effective monitoring of the various parts of the hoist operating status, provide an important basis for fault diagnosis.

Zhao, Lin; Wang, Jiqiang; Liu, Kun; Yang, Lin

2013-09-01

131

Faults and Folds Animation  

NSDL National Science Digital Library

This animation explores the forces and processes that deform rocks by creating folds, faults, and mountain ranges. You will learn how landmasses move, see the resulting deformation, and learn how this deformation relates to plate tectonics.

2002-01-01

132

Tolerance to Unbounded Byzantine Faults  

Microsoft Academic Search

An ideal approach to deal with faults in large-scale distributed systems is to contain the effects of faults as locally as possible and, additionally, to ensure some type of tolerance within each fault-affected locality. Existing results using this approach accommodate only limited faults (such as crashes) or assume that fault occurrence is bounded in space and\\/or time. In this paper,

Mikhail Nesterenko; Anish Arora

2002-01-01

133

Fault tolerant magnetic bearings  

SciTech Connect

A fault tolerant magnetic bearing system was developed and demonstrated on a large flexible-rotor test rig. The bearing system comprises a high speed, fault tolerant digital controller, three high capacity radial magnetic bearings, one thrust bearing, conventional variable reluctance position sensors, and an array of commercial switching amplifiers. Controller fault tolerance is achieved through a very high speed voting mechanism which implements triple modular redundancy with a powered spare CPU, thereby permitting failure of up to three CPU modules without system failure. Amplifier/cabling/coil fault tolerance is achieved by using a separate power amplifier for each bearing coil and permitting amplifier reconfiguration by the controller upon detection of faults. This allows hot replacement of failed amplifiers without any system degradation and without providing any excess amplifier kVA capacity over the nominal system requirement. Implemented on a large (2440 mm in length) flexible rotor, the system shows excellent rejection of faults including the failure of three CPUs as well as failure of two adjacent amplifiers (or cabling) controlling an entire stator quadrant.

Maslen, E.H.; Sortore, C.K.; Gillies, G.T.; Williams, R.D.; Fedigan, S.J. [Univ. of Virginia, Charlottesville, VA (United States); Aimone, R.J. [Mobile Technology Co., Paulsboro, NJ (United States)

1999-07-01

134

Packaged Fault Model for Geometric Segmentation of Active Faults Into Earthquake Source Faults  

NASA Astrophysics Data System (ADS)

In Japan, the empirical formula proposed by Matsuda (1975) mainly based on the length of the historical surface fault ruptures and magnitude, is generally applied to estimate the size of future earthquakes from the extent of existing active faults for seismic hazard assessment. Therefore validity of the active fault length and defining individual segment boundaries where propagating ruptures terminate are essential and crucial to the reliability for the accurate assessments. It is, however, not likely for us to clearly identify the behavioral earthquake segments from observation of surface faulting during the historical period, because most of the active faults have longer recurrence intervals than 1000 years in Japan. Besides uncertainties of the datasets obtained mainly from fault trenching studies are quite large for fault grouping/segmentation. This is why new methods or criteria should be applied for active fault grouping/segmentation, and one of the candidates may be geometric criterion of active faults. Matsuda (1990) used _gfive kilometer_h as a critical distance for grouping and separation of neighboring active faults. On the other hand, Nakata and Goto (1998) proposed the geometric criteria such as (1) branching features of active fault traces and (2) characteristic pattern of vertical-slip distribution along the fault traces as tools to predict rupture length of future earthquakes. The branching during the fault rupture propagation is regarded as an effective energy dissipation process and could result in final rupture termination. With respect to the characteristic pattern of vertical-slip distribution, especially with strike-slip components, the up-thrown sides along the faults are, in general, located on the fault blocks in the direction of relative strike-slip. Applying these new geometric criteria to the high-resolution active fault distribution maps, the fault grouping/segmentation could be more practically conducted. We tested this model successfully on the active faults generated the 1943 Tottori earthquake, the Chojagahara-Yoshii fault zone in Chugoku district in southwest Japan, as well as the active fault system in northern Luzon, the Philippines. Thus, we name this conceptual model as _gPackaged Fault Model_h and call the active faults grouped by the model as _gPackaged Faults_h for individual earthquake source faults. Moreover, we come to know that active fault mapping with _gPackaged Fault Model_h in mind enables us to find many new active fault traces (e.g., the Shigenobu fault along the MTL in Japan).

Nakata, T.; Kumamoto, T.

2004-12-01

135

Fault reactivation control on normal fault growth: an experimental study  

NASA Astrophysics Data System (ADS)

Field studies frequently emphasize how fault reactivation is involved in the deformation of the upper crust. However, this phenomenon is generally neglected (except in inversion models) in analogue and numerical models performed to study fault network growth. Using sand/silicon analogue models, we show how pre-existing discontinuities can control the geometry and evolution of a younger fault network. The models show that the reactivation of pre-existing discontinuities and their orientation control: (i) the evolution of the main fault orientation distribution through time, (ii) the geometry of relay fault zones, (iii) the geometry of small scale faulting, and (iv) the geometry and location of fault-controlled basins and depocenters. These results are in good agreement with natural fault networks observed in both the Gulf of Suez and Lake Tanganyika. They demonstrate that heterogeneities such as pre-existing faults should be included in models designed to understand the behavior and the tectonic evolution of sedimentary basins.

Bellahsen, Nicolas; Daniel, Jean Marc

2005-04-01

136

About RAPID  

Cancer.gov

The Rapid Access to Preventive Intervention Development (RAPID) Program makes the contract resources from NCI's Division of Cancer Prevention available to academic and academically-affiliated investigators for preclinical and early clinical drug development.

137

Effects of fault propagation on superficial soils/gravel aquifer properties: The Chihshang Fault in Eastern Taiwan  

NASA Astrophysics Data System (ADS)

A mature bedrock fault zone generally consists of a fault core, a damage zone, and a surrounding host rock with different permeabilities, which mainly depend on the fracture density. However, near the surface, when an active thrust fault propagates from bedrocks into an unconsolidated surface cover, it results in a diffused fault zone, which may influence the hydraulic and mechanical properties around the fault zone. It is thus of great concern to understand to which extent surface soil/gravel hydraulic properties modifications by continuously active faulting can impact geotechnical projects in countries under active tectonic context, such as Taiwan, where active faults often are blinded beneath thick soil/gravel covers. By contrast, it is also interesting to decipher those fault-induced permeability modifications to estimate potential activity precursors to large earthquakes. Here, we combined a variety of measurements and analyses on the Chihshang fault, located at the plate suture between the Philippine Sea and Eurasian plates, which converge at a rapid rate of 8 cm/yr in Taiwan. At the Chinyuan site, the Chihshang fault is propagating from depth to emerge through thick alluvial deposits. We characterized the fault geometry and slip behavior at the shallow level by measuring and analyzing horizontal, vertical displacements, and groundwater table across the surface fault zone. The yielded fault dip of 45o in the shallow alluvium is consistent with the observations from surface ruptures and subsurface core logging. The 7-year-long groundwater table record shows that the piezometric level in the hanging wall is about 8 meter higher than that in the footwall in the summer; and about 10 meter higher in the winter. Repeated slug tests have been monthly conducted since 2007 to provide the average permeability within the fault zone and the presumably low-deformed zone outside of the diffused fault zone. Based on in-situ measurements at four wells across the fault zone, a 2-D modeling of pore pressure distribution around the fault zone is conducted using the finite-difference method (FLAC3D). The results showed that the permeability within the fault zone is 10-10 cm2 and outside of the fault zone is 10-8 cm2. The low permeable zone is estimated to be about 4-5 meters thick, and its location matches with the main fault structures mapped from geological and geodetic results. This low permeability fault zone acts as a hydraulic boundary, which explains the difference in the piezometric levels observed within the soil aquifer across the fault zone. This study provides a good natural analogue to permeability changes induced by clay smearing during soft sediments faulting. It also shows the significant impact of active thrust faults on soft sediments aquifer drainage.

Mu, C.; Lee, J.; guglielmi, Y.

2013-12-01

138

Thermochronological investigation of fault zones  

NASA Astrophysics Data System (ADS)

The timing of faulting episodes can be constrained by radiometric dating of fault-zone rocks. Fault-zone material suitable for dating is produced by tectonic processes, such as (1) fragmentation of host rocks, followed by grain-size reduction and recrystallization to form mica and clay minerals, (2) secondary heating/melting of host rocks by frictional fault motions, and (3) mineral vein formation as a result of fluid advection associated with the fault motions. The thermal regime of fault zones consists primarily of the following three factors: (a) regional geothermal structure across the fault zone and background thermal history of studied province bounded by fault systems, (b) frictional heating of wall rocks by fault motions, and (c) heating of host rocks by hot fluid advection in and around the fault zone. Thermochronological methods widely applied in fault zones are K-Ar (40Ar/39Ar), fission-track, and U-Th methods, for which methodological principles as well as analytical procedures are briefly described. The thermal sensitivities of individual thermochronological systems are then reviewed, which critically control the response of each method against the thermal processes. Based on the knowledge above, representative examples as well as key issues are highlighted to date fault gouges, pseudotachylytes, mylonites and carbonate veins, placing new constraints upon geological, geomorphological and seismological frames. Finally, the Nojima Fault is presented as an example for multiple applications of thermochronological methods in a complex fault zone.

Tagami, Takahiro

2012-05-01

139

Insurance Applications of Active Fault Maps Showing Epistemic Uncertainty  

NASA Astrophysics Data System (ADS)

Insurance loss modeling for earthquakes utilizes available maps of active faulting produced by geoscientists. All such maps are subject to uncertainty, arising from lack of knowledge of fault geometry and rupture history. Field work to undertake geological fault investigations drains human and monetary resources, and this inevitably limits the resolution of fault parameters. Some areas are more accessible than others; some may be of greater social or economic importance than others; some areas may be investigated more rapidly or diligently than others; or funding restrictions may have curtailed the extent of the fault mapping program. In contrast with the aleatory uncertainty associated with the inherent variability in the dynamics of earthquake fault rupture, uncertainty associated with lack of knowledge of fault geometry and rupture history is epistemic. The extent of this epistemic uncertainty may vary substantially from one regional or national fault map to another. However aware the local cartographer may be, this uncertainty is generally not conveyed in detail to the international map user. For example, an area may be left blank for a variety of reasons, ranging from lack of sufficient investigation of a fault to lack of convincing evidence of activity. Epistemic uncertainty in fault parameters is of concern in any probabilistic assessment of seismic hazard, not least in insurance earthquake risk applications. A logic-tree framework is appropriate for incorporating epistemic uncertainty. Some insurance contracts cover specific high-value properties or transport infrastructure, and therefore are extremely sensitive to the geometry of active faulting. Alternative Risk Transfer (ART) to the capital markets may also be considered. In order for such insurance or ART contracts to be properly priced, uncertainty should be taken into account. Accordingly, an estimate is needed for the likelihood of surface rupture capable of causing severe damage. Especially where a high deductible is in force, this requires estimation of the epistemic uncertainty on fault geometry and activity. Transport infrastructure insurance is of practical interest in seismic countries. On the North Anatolian Fault in Turkey, there is uncertainty over an unbroken segment between the eastern end of the Dazce Fault and Bolu. This may have ruptured during the 1944 earthquake. Existing hazard maps may simply use a question mark to flag uncertainty. However, a far more informative type of hazard map might express spatial variations in the confidence level associated with a fault map. Through such visual guidance, an insurance risk analyst would be better placed to price earthquake cover, allowing for epistemic uncertainty.

Woo, G.

2005-12-01

140

Investigation of Active Fault Scarps by Means of Geophysical Prospecting Methods, Javakheti Fault Case, Georgia  

NASA Astrophysics Data System (ADS)

Current presentation concerns investigation of Javakheti seismically active fault (Georgia, South Caucasus region) by means of Geophysical prospecting methods, carried out during the past two years. The named fault represents the major seismo tectonic structure at Javakhety volcanic highland. Fault segments at some places are well expressed on surface and several of those were mapped even during the Geologic surveys carried in 60-70's of previous century, though not recognized as a single structure. Detailed study of seismically active faults is an important component for proper seismic hazard assessment. Fault scarps, an evidence of fault's activity, are expressed on the earth surface as a result of accumulated rapid displacements due to earthquakes. Geomorphologic studies could provide us with rather general information about the fault, while much more information can be derived from paleo trenching and borehole coring. Unfortunately these methods are quite expensive and time consuming, requiring significant technical and man resources. Shallow Geophysical prospecting methods seems to be a valuable addition to above mentioned techniques. In our case extensive Geophysical prospecting surveys, preceded by Geomorphologic and Geologic Surveys have provided valuable information, first of all for correct identification of fault but also regarding the fault dynamics and internal structure of scarps. During this year geophysical studies were followed by paleo trenching at two locations, preliminary selected based on Geophysical data. Both trenches appeared to be successful, were revealed tracks of several paleo earthquakes currently under processing. Studies were also focused on development of Geophysical prospecting techniques and Interpretation of the results. During the past two years fault scarps were studied by means of Seismic prospecting methods (refracted waves, 2D tomography and surface waves), electric resistivity and Ground Penetrating Radar (200 and 80 MHz antennas). Al these rather inexpensive methods were applied along the same profiles, supplementing each other and providing favorable conditions for analysis and interpretation. As mentioned above, two of the profiles were excavated providing ground truth data and giving more confidence two our interpretations. Presumably, the approaches developed and accumulated experience could be of interest for future studies.

Elashvili, M.; Sakhelashvili, G.; Gigiberia, M.; Maisaia, I.; Godoladze, T.; Javakhishvili, Z.; Durgaryan, R.; Gevorgyan, M.

2011-12-01

141

Fault terminations, Seminoe Mountains, Wyoming  

SciTech Connect

Two basement-involved faults terminate in folds in the Seminoe Mountains. Mesoscopic and macroscopic structures in sedimentary rocks provide clues to the interrelationship of faults and folds in this region, and on the linkage between faulting and folding in general. The Hurt Creek fault trends 320[degree] and has maximum separation of 1.5 km measured at the basement/cover contact. Separation on the fault decreases upsection to zero within the Jurassic Sundance Formation. Unfaulted rock units form an anticline around the fault tip. The complementary syncline is angular with planar limbs and a narrow hinge zone. The syncline axial trace intersects the fault in the footwall at the basement/cover cut-off. Map patterns are interpreted to show thickening of Mesozoic units adjacent to the syncline hinge. In contrast, extensional structures are common in the faulted anticline within the Permian Goose Egg and Triassic Chugwater Formations. A hanging wall splay fault loses separation into the Goose Egg formation which is thinned by 50% at the fault tip. Mesoscopic normal faults are oriented 320--340[degree] and have an average inclination of 75[degree] SW. Megaboudins of Chugwater are present in the footwall of the Hurt Creek fault, immediately adjacent to the fault trace. The Black Canyon fault transported Precambrian-Pennsylvanian rocks over Pennsylvanian Tensleep sandstone. This fault is layer-parallel at the top of the Tensleep and loses separation along strike into an unfaulted syncline in the Goose Egg Formation. Shortening in the pre-Permian units is accommodated by slip on the basement-involved Black Canyon fault. Equivalent shortening in Permian-Cretaceous units occurs on a system of thin-skinned'' thrust faults.

Dominic, J.B.; McConnell, D.A. (Univ. of Akron, OH (United States). Dept. of Geology)

1992-01-01

142

A healing-reloading feedback control on the growth rate of seismogenic faults  

NASA Astrophysics Data System (ADS)

Spatial and temporal variations in the growth rates of faults are explained in terms of a stress feedback mechanism operating in the seismogenic upper crust. It is based on the idea that seismic rupture of a fault perturbs the surrounding stress field, advancing the occurrence of future earthquakes on some faults that are optimally oriented while relaxing stress levels on others. If post-slip healing is geologically rapid, then the earthquakes that are thus induced will contribute to reloading along the earlier rupture zone because of the symmetry of the optimal geometry. A positive feedback is set up so that, even in areas that are undergoing uniform tectonic straining, some faults develop higher displacement rates and grow more rapidly while others experience reduced rates or become inactive. Using a thin plate elastic model for lithospheric-scale faulting, it is shown that this healing-reloading feedback mechanism drives rapid localisation and the formation of major through-going faults moving at plate boundary velocities. Enhanced displacement rates (compared to an isolated fault) develop shortly after the onset of deformation along those faults which are optimally positioned in the overall fault population. Thus the formation of a new plate boundary fault zone is predetermined and is a consequence of, rather than the precursor of, preferentially high displacement rates. Also, fault segments located at points of rupture symmetry, e.g. the central portion of a fault zone, are reloaded more frequently and develop higher displacement rates and consequently have longer segment lengths and/or larger displacement to length ratios. Episodic fault movement through time is a general feature of the model. These predictions are consistent with available field observations over a wide range of scales. Thus, elastic-brittle failure and healing appear to be important rheological components of the lithosphere on long time scales (10 4-10 6 y), as well as on the time scale of earthquake recurrence.

Cowie, P. A.

1998-08-01

143

An Empirical Comparison of Software Fault Tolerance and Fault Elimination  

Microsoft Academic Search

The authors compared two major approaches to the improvement of software-software fault elimination and software fault tolerance-by examination of the fault detection (and tolerance, where applicable) of five techniques: run-time assertions, multiversion voting, functional testing augmented by structural testing, code reading by stepwise abstraction, and static data-flow analysis. The focus was on characterizing the sets of faults detected by the

Timothy J. Shimeall; Nancy G. Leveson

1991-01-01

144

Computer hardware fault administration  

DOEpatents

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.

Archer, Charles J. (Rochester, MN); Megerian, Mark G. (Rochester, MN); Ratterman, Joseph D. (Rochester, MN); Smith, Brian E. (Rochester, MN)

2010-09-14

145

Ius Chasma Fault  

NASA Technical Reports Server (NTRS)

MGS MOC Release No. MOC2-415, 8 July 2003

This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a 'text-book example' of an offset in layered rock caused by a fault. The offset is most easily seen near the upper right of the image. The martian crust is faulted, and the planet has probably experienced 'earthquakes' (or, marsquakes) in the past. This scene is located on the floor of Ius Chasma near 7.8oS, 80.6oW. Sunlight illuminates the scene from the upper left.

2003-01-01

146

Shallow faults mapped with seismic reflections: Lost River Fault, Idaho  

Microsoft Academic Search

A high-resolution seismic-reflection survey, conducted at the intersection of Arentson Gulch road and the western splay of the Lost River fault scarp in central Idaho, defines a bedrock surface about 80 m deep which is segmented by several faults forming graben structures. Six meters of total fault displacement can be interpreted on the bedrock reflector while only 1 to 2

Mubarik Ali; Richard D. Miller; Don W. Steeples

1991-01-01

147

Shallow faults mapped with seismic reflections: Lost River fault, Idaho  

Microsoft Academic Search

A high-resolution seismic-reflection survey, conducted at the intersection of Arentson Gulch road and the western splay of the Lost River fault scarp in central Idaho, defines a bedrock surface about 80 m deep which is segmented by several faults forming graben structures. Six meters of total fault displacement can be interpreted on the bedrock reflector while only 1 to 2

Mubarik Ali; Richard D. Miller; Don W. Steeples

1991-01-01

148

Subsurface fault geometry inferred from topographic relief and footwall geologic information: An example from the Ikoma fault zone, southwest Japan  

NASA Astrophysics Data System (ADS)

To improve seismic hazard assessment caused by inland earthquakes, it is necessary to clarify subsurface fault geometry and fault slip sense. Although seismic reflection profiles are commonly used to image subsurface fault geometry and associated deformation, there are numerous technical and conditional limitations that often prevent us seeing deeper extension of the fault. To perform the best estimate of the subsurface fault at seismogenic depth, we use all the geomorphic and geologic information to better constrain numerical fault models. Here we choose the Ikoma fault zone, east of the Osaka plain, southwest Japan, as a case study to infer subsurface fault geometry with a great deal of shallow geologic information. The Ikoma fault zone composes a part of NS-trending topographic relief of basins and ranges in Osaka-Kyoto region where significant EW contraction has been continuously occurring in the late Quaternary (Huzita, 1962). To model the east Osaka basin and the Ikoma Mountains, both of which corresponds to footwall and hanging wall of the Ikoma fault, we employ dislocation model in an elastic half space of Okada (1992). We first calculate surface displacement with a simple rectangular fault, and then compare with the present topographic profile across the fault. We find our best estimate of the fault width, dip, and top depth to maximize the cross correlation and/or to minimize the root mean square of the residual between the model and the topographic profile by grid search technique. Since we apply the dislocation model to the topographic profile across an active fault, we introduce information of the confirmed fault position at the Earth's surface into our model when calculated displacement pattern and topographic cross section are compared. Our result shows that a 14-km-wide shallow dipping thrust fault better explains the topographic relief across the Ikoma fault. However, such fault models cannot reproduce the basin-forming deformation on the footwall. Numerous geologic data of pre-Tertiary bedrock, Pleistocene to Holocene marine and non-marine sediments beneath the Osaka plane (e.g., Horikawa et al., 2003) provide several well-constrained chronological key units which allow us to incorporate the information into our models. In the case of bedrock deformation, our best estimate is a combination of fault width 19km, dip 50°, and top depth 2 km. To explain the thick Quaternary sedimentary units up to ~1,500 m on the footwall, fault dip must be deeper than 50°. None of the traditional geologic fold models (e.g., fault-propagation fold), most of which take detachment into account, can explain such significant basin subsidence. However, one could criticize limitations of the elastic half space model for the long-term geologic processes of tens of thousand years to a few million years. We thus intend to perform further experiments considering viscoelastic relaxation of lower crust, topographic change in upheaval side due to rapid surface erosion, newly-formed dislocation (fault) beyond elaselastic limit.

Tani, E.; Toda, S.

2013-12-01

149

Fault Rate Acceleration and Low Angle Normal Faulting: The Hunter Mountain Fault, California.  

NASA Astrophysics Data System (ADS)

The Panamint Valley, Hunter Mountain, Saline Range (PHS) faults are, together with the Death Valley and Owens Valley faults, one of the three major fault zones within the Eastern California Shear Zone (ECSZ). The ECSZ is the most active fault system bounding the Basin and Range to the southwest with approximately 10 mm/yr of cumulative slip along strike-slip and trans-tensional segments. Interferometry Synthetic Aperture Radar (InSAR) is a geodetic technique that allows measurement of ground motion at a mm/yr accuracy over large areas with a high measurement sampling. We processed a large number of data to investigate ground motion in the PHS fault system to shed light on the interseismic strain accumulation and its relation to the fault geometry. Results indicate high strain rate over the Hunter Mountain fault, possibly showing slip rate acceleration of the fault since inception time. The locking depth of the fault inferred from elastic modeling of interseismic strain accumulation is on the order of a few kilometers, significantly shallower than for neighboring faults. The shallow locking depth inferred for the Hunter Mountain fault corresponds to the extension at depth of two suggested bounding low angle normal faults. This finding reinforced recent field study findings about possible activity of the low angle normal fault system.

Gourmelen, N.; Amelung, F.; Dixon, T.; Manzo, M.; Casu, F.; Pepe, A.; Lanari, R.

2008-05-01

150

Impacts of Fault Geometry on Fault System Behaviors  

NASA Astrophysics Data System (ADS)

Complexity in earthquake populations arises primarily due to two components: friction and fault geometry. We present preliminary investigations into contributions to event population complexity due to fault geometry variation. In one key application, we investigate probabilities of events continuing along multiple, en echelon fault segments in both compressional and extensional regimes as a function of distance between the segments and segment overlap. These and other results are produced in the course of developing the extended finite element method, XFEM (e.g. [Dolbow, Moes, and Belytschko, 2001]), for static, quasistatic, and dynamic rupture problems on complicated fault networks. This method, part of a broader class of mesh-free methods, allow faults to be included nearly arbitrarily in a simulation, enabling many simulations with varying fault geometries to be conducted with minimal remeshing. We introduce the enforcement of failure criteria in dynamic rupture problems and test the method through a series of two-dimensional static and dynamic benchmarks. We also introduce a novel, ``two and a half-dimensional'' formulation, where two-dimensional plates intersect at faults that include a dip parameter which can vary along-strike. This enables us to model fault systems with strike-slip, thrust, normal, and mixed-mode faults. To demonstrate this capability, we examine fault systems composed of faults taken from the SCEC Community Fault Model Surface Traces. These results demonstrate the feasibility of the XFEM for both static and dynamic rupture problems. Furthermore, we demonstrate usage of the XFEM in studies with uncertain fault geometry, and enable new studies of fault system behaviors due to fault geometry.

Coon, E. T.; Shaw, B. E.; Spiegelman, M. W.

2009-12-01

151

Measurements and tests of HTS bulk material in resistive fault current limiters  

Microsoft Academic Search

The application of superconducting fault current limiters (SCFCL) depends highly on their technical and economical benefits. Therefore it is obvious that the main requirements on the SCFCL are a reliable, fail-safe and rapid current limitation, low losses, and an inexpensive production.As a potential candidate material we have investigated HTS bulk material in resistive fault current limiters. Our report focuses on

M. Noe; K.-P Juengst; F. N Werfel; S. Elschner; J. Bock; A. Wolf; F. Breuer

2002-01-01

152

Fault Detection in Routing Protocols  

Microsoft Academic Search

Routing protocol faults cause problems ranging from an inability to communicate to excessive routing overhead. This paper proposes a system for detecting a wide range of routing protocol faults. Our system deploys virtual routers called RouteMonitors to monitor a routing protocol. We de- ployed RouteMonitors in the MBone's DVMRP infrastruc- ture and uncovered a number of faults. We were also

Daniel Massey; Bill Fenner

1999-01-01

153

Improving fault handling software techniques  

Microsoft Academic Search

The paper presents the new software library supporting development of the fault-robust applications. The main goals of the proposed software hardening mechanisms are: usage simplicity for the programmer, independence from the development tool, effectiveness in terms of fault coverage, low static and dynamic overheads. The paper describes implemented software mechanisms and discusses their effectiveness verified with fault injection experiments.

Piotr Gawkowski; Tomasz Rutkowski; Janusz Sosnowski

2010-01-01

154

Modelling the Fault Correction Process  

Microsoft Academic Search

In general, software reliability models have focused on modeling and predicting failure occurrence and have not given equal priority to modeling the fault correction process. However, there is a need for fault correction prediction, because there are important applications that fault correction modeling and prediction support. These are the following: predicting whether reliability goals have been achieved, developing stopping rules

Norman F. Schneidewind

2001-01-01

155

Fault testing quantum switching circuits  

Microsoft Academic Search

Test pattern generation is an electronic design automation tool that attempts to find an input (or test) sequence that, when applied to a digital circuit, enables one to distinguish between the correct circuit behavior and the faulty behavior caused by particular faults. The effectiveness of this classical method is measured by the fault coverage achieved for the fault model and

Jacob Biamonte; Marek Perkowski

2005-01-01

156

Row fault detection system  

DOEpatents

An apparatus and program product check for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

Archer, Charles Jens (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Ratterman, Joseph D. (Rochester, MN); Smith, Brian Edward (Rochester, MN)

2010-02-23

157

Fault tolerant anonymous channel  

Microsoft Academic Search

Previous anonymous channels, called MIX nets, do not workif one center stops. This paper shows new anonymous channels which allowless than a half of faulty centers. A fault tolerant multivalued electionscheme is obtained automatically. A very efficient ZKIP for the centersis also presented.

Wakaha Ogata; Kaoru Kurosawa; Kazue Sako; Kazunori Takatani

1997-01-01

158

Row fault detection system  

DOEpatents

An apparatus, program product and method checks for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

Archer, Charles Jens (Rochester, MN) [Rochester, MN; Pinnow, Kurt Walter (Rochester, MN) [Rochester, MN; Ratterman, Joseph D. (Rochester, MN) [Rochester, MN; Smith, Brian Edward (Rochester, MN) [Rochester, MN

2008-10-14

159

Row fault detection system  

DOEpatents

An apparatus, program product and method check for nodal faults in a row of nodes by causing each node in the row to concurrently communicate with its adjacent neighbor nodes in the row. The communications are analyzed to determine a presence of a faulty node or connection.

Archer, Charles Jens (Rochester, MN); Pinnow, Kurt Walter (Rochester, MN); Ratterman, Joseph D. (Rochester, MN); Smith, Brian Edward (Rochester, MN)

2012-02-07

160

Formal Fault Tree Semantics  

Microsoft Academic Search

In train control systems, more and more (electro-)mechanical devices are substituted by software based devices. To sustain the high level safety standards for these embedded systems, we propose the integration of fault tree analysis and formal methods. This combines two important safety analysis methods from the involved domains of engineering and software development. Our approach proposes to build a formal

Gerhard Schellhorn; Andreas Thums; Wolfgang Reif Lehrstuhl

2002-01-01

161

Fault isolation techniques  

NASA Technical Reports Server (NTRS)

Three major areas that are considered in the development of an overall maintenance scheme of computer equipment are described. The areas of concern related to fault isolation techniques are: the programmer (or user), company and its policies, and the manufacturer of the equipment.

Dumas, A.

1981-01-01

162

Structural Evidence for Fault Reactivation: the Active Priene-Sazli Fault Zone, Söke-Milet Basin, Western Anatolia  

NASA Astrophysics Data System (ADS)

Western Anatolia is located at tha eastern part of the Aegean region that forms one of the most seismically active and rapidly extending regions in the world. One of the most prominent structural component of the Western Anatolia is E-W trending grabens. One of them is the Büyük Menderes Graben (BMG) showing a major change in strike ranging from E-W to NE-SW in its western end. This NE-SW oriented part of the graben is known as the Söke-Milet basin (SMB). The depression is 35 km long and 16 km wide. NW border of the basin is characterized by a morphotectonic structure namely Priene-Sazl? fault zone (PSFZ). The 16 July 1955 Söke-Balat earthquake (M=6.8) was atributed to this fault (Eyidogan and Jackson, 1985; Sengör, 1987; Altunel, 1998). However, field based kinematic studies on the PSFZ are lacking except for Gürer et. al. (2001). In this paper, we studied several reactivated fault segments of the PSFZ that are repeatedly formed under changing stress fields in order to evaluate the kinematic and stress history of the region by using structural relationships between striations and fault-plane related structures. The PSFZ consists of 5 fault segments which are en échelon arranged on the basis of mapping geological structures. The northern segments that strikes NE in the north and bends into an approximately E-W direction around Doganbey to the SW. Each segment is identified as steep opographic scarps ranging in height from a few meters to several hundred meters. Fault segments become to linkage and show breaching of the relay ramps between them. We interpret that such fault patterns have been formed in a region where extension has reactivated on pre-existing structures in an oblique sense. Evidence for this is the presence of three sets of striations each with different orientations on the same slip surface of the studied fault segments. Here, two differently oriented strike-slip slickenlines are postdated by dip-slip striations. Based on our structural observations, we suggest different episodes of fault evolution for the PSFZ; (i) first the fault formed as a dextral strike-slip faulting, (ii) then, sense of the direction was sinistral oblique-slip (iii) and finally PSFZ was reactivated during the Quaternary as an approximately pure dip-slip normal fault. Key words: Reactivation, strike-slip fault, active fault, western Anatolia This study is supported by Dokuz Eylül University Research Projects "AFS- 0908.01.06.02" and "BAP-03 KB FEN 047", "BAP- 04 KB FEN 042", "BAP- 07 KB FEN 047".

Sümer, Ö.; Inci, U.; Sözbilir, H.; Uzel, B.

2009-04-01

163

Earthquakes and fault creep on the northern San Andreas fault  

USGS Publications Warehouse

At present there is an absence of both fault creep and small earthquakes on the northern San Andreas fault, which had a magnitude 8 earthquake with 5 m of slip in 1906. The fault has apparently been dormant after the 1906 earthquake. One possibility is that the fault is 'locked' in some way and only produces great earthquakes. An alternative possibility, presented here, is that the lack of current activity on the northern San Andreas fault is because of a lack of sufficient elastic strain after the 1906 earthquake. This is indicated by geodetic measurements at Fort Ross in 1874, 1906 (post-earthquake), and 1969, which show that the strain accumulation in 1969 (69 ?? 10-6 engineering strain) was only about one-third of the strain release (rebound) in the 1906 earthquake (200 ?? 10-6 engineering strain). The large difference in seismicity before and after 1906, with many strong local earthquakes from 1836 to 1906, but only a few strong earthquakes from 1906 to 1976, also indicates a difference of elastic strain. The geologic characteristics (serpentine, fault straightness) of most of the northern San Andreas fault are very similar to the characteristics of the fault south of Hollister, where fault creep is occurring. Thus, the current absence of fault creep on the northern fault segment is probably due to a lack of sufficient elastic strain at the present time. ?? 1979.

Nason, R.

1979-01-01

164

Fault Scarp Offsets and Fault Population Analysis on Dione  

NASA Astrophysics Data System (ADS)

Cassini images of Dione show several fault zones cutting through the moon’s icy surface. We have measured the displacement and length of 271 faults, and estimated the strain occurring in 6 different fault zones. These measurements allow us to quantify the total amount of surface strain on Dione as well as constrain what processes might have caused these faults to form. Though we do not have detailed topography across fault scarps on Dione, we can use their projected size on the camera plane to estimate their heights, assuming a reasonable surface slope. Starting with high resolution images of Dione obtained by the Cassini ISS, we marked points at the top to the bottom of each fault scarp to measure the fault’s projected displacement and its orientation along strike. Line and sample information for the measurements were then processed through ISIS to derive latitude/longitude information and pixel dimensions. We then calculate the three dimensional orientation of a vector running from the bottom to the top of the fault scarp, assuming a 45 degree angle with respect to the surface, and project this vector onto the spacecraft camera plane. This projected vector gives us a correction factor to estimate the actual vertical displacement of the fault scarp. This process was repeated many times for each fault, to show variations of displacement along the length of the fault. To compare each fault to its neighbors and see how strain was accommodated across a population of faults, we divided the faults into fault zones, and created new coordinate systems oriented along the central axis of each fault zone. We could then quantify the amount of fault overlap and add the displacement of overlapping faults to estimate the amount of strain accommodated in each zone. Faults in the southern portion of Padua have a strain of 0.031(+/-) 0.0097, central Padua exhibits a strain of .032(+/-) 0.012, and faults in northern Padua have a strain of 0.025(+/-) 0.0080. The western faults of Eurotas have a strain of 0.031(+/-) 0.011, while the eastern faults have a strain of 0.037(+/-) 0.025. Lastly, Clusium has a strain of 0.10 (+/-) 0.029. We also calculated the ratio of maximum fault displacement vs. the length of the faults, and we found this ratio to be 0.019 when drawing a trend line through all the faults that were analyzed. D/L measurements performed on two faults on Europa using stereo topography showed a value of .021 (Nimmo and Schenk 2006), the only other icy satellite where this ratio has been measured. In contrast, faults on Earth has a D/L ratio of about .1 and Mars has a D/L Ratio of about .01 (Schultz et al. 2006).

Tarlow, S.; Collins, G. C.

2010-12-01

165

An empirical comparison of software fault tolerance and fault elimination  

NASA Technical Reports Server (NTRS)

Reliability is an important concern in the development of software for modern systems. Some researchers have hypothesized that particular fault-handling approaches or techniques are so effective that other approaches or techniques are superfluous. The authors have performed a study that compares two major approaches to the improvement of software, software fault elimination and software fault tolerance, by examination of the fault detection obtained by five techniques: run-time assertions, multi-version voting, functional testing augmented by structural testing, code reading by stepwise abstraction, and static data-flow analysis. This study has focused on characterizing the sets of faults detected by the techniques and on characterizing the relationships between these sets of faults. The results of the study show that none of the techniques studied is necessarily redundant to any combination of the others. Further results reveal strengths and weakness in the fault detection by the techniques studied and suggest directions for future research.

Shimeall, Timothy J.; Leveson, Nancy G.

1991-01-01

166

Fault zone structure of the Wildcat fault in Berkeley, California - Field survey and fault model test -  

Microsoft Academic Search

In order to develop hydrologic characterization technology of fault zones, it is desirable to clarify the relationship between the geologic structure and hydrologic properties of fault zones. To this end, we are performing surface-based geologic and trench investigations, geophysical surveys and borehole-based hydrologic investigations along the Wildcat fault in Berkeley,California to investigate the effect of fault zone structure on regional

K. Ueta; C. T. Onishi; K. Karasaki; S. Tanaka; T. Hamada; T. Sasaki; H. Ito; K. Tsukuda; K. Ichikawa; J. Goto; T. Moriya

2010-01-01

167

Reconstructing Fault History from Fault Rocks and Travertine Deposits, Rock Canyon Fault, Utah  

NASA Astrophysics Data System (ADS)

Central Utah lies along the eastern border of the Basin and Range Province. Within this region the Rock and Dry Canyon's graben structure is a block dropped down by oblique faults with an anomalous east-west orientation relative to other Basin and Range structures. Travertine is a rock composed of calcium carbonate that is commonly associated with faults, particularly active faults. The geometry and the macro/microstructures of travertine can provide a record of the evolution of the fault through time. The objectives of this study are to document the evidence of fault history contained in travertine formed along the Rock Canyon fault in order to test the hypothesis that this is a young, potentially active structure contributing to Basin and Range Province deformation. Polished rock slabs prepared from travertine samples collected along the mapped Rock Canyon fault show a wide range of textures, including columnar, radial/fibrous, banded, bedded, botryoidal, and brecciated travertine (broken, cemented fault rock) along with fibrous, brecciated, and blocky crystalline calcite. Angular clasts of layered travertine, deposited along the fault at an earlier stage, are contained within breccias documenting a subsequent slip event (or events). Therefore, initial observations on fault rock textures indicate that there were multiple slip episodes on the Rock Canyon fault. More detailed microscopic observations on thin sections prepared from the same samples will constrain the number and type of fracturing, fault slip, and vein precipitation events that occurred.

Main, J.; Wilson, T. J.

2011-12-01

168

Effect of surrounding fault on distributed fault of blind reverse fault in sedimentary basin - Uemachi Faults, Osaka Basin, Southwest Japan -  

NASA Astrophysics Data System (ADS)

Several large cities and metropolitan areas, such as Osaka and Kobe are located in the Osaka basin, which has been filled by the Pleistocene Osaka group and the later sediments. 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 various geological, geophysical surveys, such as seismic reflection, micro tremor, gravity surveys and deep boreholes, revealed the complex basement configuration along the Uemachi faults. The depth of the basement is shallow in the central part of the Osaka plain. The Uemachi faults are locates on the western side of the basement upland. In the central part of the Uemachi faults, the displacement decreases. The fault model of the Uemachi faults consists of the two parts, the north and south parts. The NE-SW trending branch faults, Suminoe and Sakuragawa flexures, are also recognized based on various surveys around the central part. Kusumoto et al. (2001) reported that surrounding faults enable to form the basement configuration without the Uemachi faults model based on a dislocation model. Inoue et al. (2011) 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 of 7 faults including the Uemachi faults. In this study, the Osaka-wan fault was considered for the dislocation model. The results show the basement configuration including NE-SW branch faults. The basement configuration differs from the subsurface structure derived from the investigation of abundance geotechnical borehole data around the central part of the Uemachi faults. The tectonic developing process including the erosion and sea level change are require to understanding the structure from the basement to the surface of the Uemachi Fault Zone. This research is partly funded by the Comprehensive Research on the Uemachi Fault Zone (in FY2010 and FY2011) by MEXT.

Inoue, N.

2012-12-01

169

Is Jiali Fault still an active fault in the late Pleistocene?  

Microsoft Academic Search

The Karakoram-Jiali Fault Zone (KJFZ) is the most important active structure system in the Tibetan Plateau. This zone consists of two major faults (i.e., Karakoram fault and Jiali fault) and other minor faults in between. The Karakoram fault strikes NW to SE in the western Tibet, while the Jiali fault roughly EW in the eastern Tibet, According to previous study,

L. Chung; Y. Chen; K. Lai; G. Yin; Z. Cao

2007-01-01

170

Microseismicity, fault structure, & the seismic cycle: Insights from laboratory stick-slip experiments  

NASA Astrophysics Data System (ADS)

The deformation along tectonic plate boundaries is associated with the storage and release of elastic energy. The abrupt release of strain energy results in seismic energy emission during fault slip, i.e., earthquake ruptures. The dynamics of these earthquakes, including the nucleation, propagation and arrest of ruptures, is closely tied to local fault zone properties. However, the details of how fault zone properties influence small and large earthquakes is insufficiently understood, partially due to limited observations of fault zone structure at seismogenic depths, and necessarily incomplete seismic catalogs. Here, we investigate the connection between micro-seismicity, and variations in fault stress and structure during series of stick-slip experiments on structurally-complex fault zones generated in natural granite samples. Within the present experimental series, we strove to mimic the natural faulting process by creating series of stick-slip events under seismogenic stress conditions on complex faults. Throughout the experiments, we monitored variations in stress, strain, and seismic activity. The latter was compared to post-experimental micro-structure of faults observed in computer tomography images and thin sections. Our laboratory-created faults exhibited many of the structural hallmarks of faults in nature. Moreover, the observed seismic event distributions show many similarities to natural seismicity, including Omori-Utsu type aftershock decays, Gutenberg-Richter frequency magnitude distributions, power-law off-fault activity decays, and fractal hypocenter distributions. The spatial and temporal variations in seismic event distributions in our experiments can be explained through variations in fault structure and stress. At high stresses and in the proximity to fault asperity regions, micro-seismic events tend to cluster, and show low b-values as well as high seismic moment release. Furthermore, our laboratory experiments provide insight into the creation of off-fault damage and resulting variations in micro-seismicity distributions. The off-fault micro-seismic events decay as a power-law at larger fault-normal distance with an exponent that is connected to fault roughness and normal stress. Our laboratory faults showed rapid structural evolution toward less complexity, however, evolutionary processes were predominantly limited to initial seismic cycles. Our results emphasize that small seismic events contain essential information about fault properties, e.g., roughness, structural heterogeneity and stress level, which in turn may control the dynamics of large earthquakes. A detailed analysis of micro-seismicity statistics and inferred fault properties therefore have the potential to significantly advance the seismic hazard assessment of active tectonic regions.

Gobel, Thomas H. W.

171

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

NASA Technical Reports Server (NTRS)

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.

Padilla, Peter A.

1991-01-01

172

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

NASA Astrophysics Data System (ADS)

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.

Padilla, Peter A.

1991-03-01

173

An expert system for fault diagnosis in a Space Shuttle main engine  

NASA Technical Reports Server (NTRS)

The detection and diagnosis of SSME faults in an early stage is important in order to allow enough time for fault preventive or corrective measurements. Since most of the faults in a complex system like SSME develop rapidly, early detection and diagnosis of faults is critical for the survival of space vehicles. An expert system has been designed for automatic learning, detection, identification, verification, and correction of anomalous propulsion system operations. This paper describes an innovative machine learning approach which is employed for the automatic training of this expert system.

Ali, Moonis; Gupta, U. K.

1990-01-01

174

Managing Fault Management Development  

NASA Technical Reports Server (NTRS)

As the complexity of space missions grows, development of Fault Management (FM) capabilities is an increasingly common driver for significant cost overruns late in the development cycle. FM issues and the resulting cost overruns are rarely caused by a lack of technology, but rather by a lack of planning and emphasis by project management. A recent NASA FM Workshop brought together FM practitioners from a broad spectrum of institutions, mission types, and functional roles to identify the drivers underlying FM overruns and recommend solutions. They identified a number of areas in which increased program and project management focus can be used to control FM development cost growth. These include up-front planning for FM as a distinct engineering discipline; managing different, conflicting, and changing institutional goals and risk postures; ensuring the necessary resources for a disciplined, coordinated approach to end-to-end fault management engineering; and monitoring FM coordination across all mission systems.

McDougal, John M.

2010-01-01

175

Randomness fault detection system  

NASA Technical Reports Server (NTRS)

A method and apparatus are provided for detecting a fault on a power line carrying a line parameter such as a load current. The apparatus monitors and analyzes the load current to obtain an energy value. The energy value is compared to a threshold value stored in a buffer. If the energy value is greater than the threshold value a counter is incremented. If the energy value is greater than a high value threshold or less than a low value threshold then a second counter is incremented. If the difference between two subsequent energy values is greater than a constant then a third counter is incremented. A fault signal is issued if the counter is greater than a counter limit value and either the second counter is greater than a second limit value or the third counter is greater than a third limit value.

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

1996-01-01

176

Fault tolerant mechanism design  

Microsoft Academic Search

Abstract We introduce the notion of fault tolerant mechanism design, which ex- tends the standard game,theoretic framework,of mechanism,design to allow for uncertainty about execution. Specically, we dene the problem of task allocation in which the private information of the agents is not only their costs of attempting the tasks but also their probabilities of failure. For several dif- ferent instances

Ryan Porter; Amir Ronen; Yoav Shoham; Moshe Tennenholtz

2008-01-01

177

Dynamic Fault Detection Chassis  

Microsoft Academic Search

The high frequency switching megawatt-class High Voltage Converter Modulator (HVCM) developed by Los Alamos National Laboratory for the Oak Ridge National Laboratory's Spallation Neutron Source (SNS) is now in operation. One of the major problems with the modulator systems is shoot-thru conditions that can occur in a IGBTs H-bridge topology resulting in large fault currents and device failure in a

Mize; Jeffery J

2007-01-01

178

Practical quantum fault tolerance  

NASA Astrophysics Data System (ADS)

The standard approach to quantum fault tolerance is to calculate error thresholds on basic gates in the limit of arbitrarily many concatenation levels. In contrast this paper takes the number of qubits and the target implementation accuracy as given, and provides a framework for engineering the constrained quantum system to the required tolerance. The approach requires solving the full dynamics of the quantum system for an arbitrary admixture (biased or unbiased) of Pauli errors. The inaccuracy between ideal and implemented quantum systems is captured by the supremum of the Schatten k-norm of the difference between the ideal and implemented density matrices taken over all density matrices. This is a more complete analysis than the standard approach, where an intricate combination of worst case assumptions and combinatorial analysis is used to analyze the special case of equiprobable errors. Conditions for fault tolerance are now expressed in terms of error regions rather than a single number (the standard error threshold). In the important special case of a stochastic noise model and a single logical qubit, an optimization over all 2×2 density matrices is required to obtain the full dynamics. The complexity of this calculation is greatly simplified through reduction to an optimization over only three projectors. Error regions are calculated for the standard 5- and 7-qubit codes. Knowledge of the full dynamics makes it possible to design sophisticated concatenation strategies that go beyond repeatedly using the same code, and these strategies can achieve target fault tolerance thresholds with fewer qubits.

Gilbert, G.; Weinstein, Y. S.; Aggarwal, V.; Calderbank, A. R.

2009-05-01

179

The South Marmara Fault  

NASA Astrophysics Data System (ADS)

We use about 800 km of multichannel exploration seismic reflection profiles of the seventies as well as the results of three drill holes that penetrated the sedimentary cover down to the Upper Cretaceous basement to describe a continuous gently curvilinear, south-concave zone of deformation about 10 km wide that extended over the whole southern shelf of the Sea of Marmara from the Gulf of Gemlik to the Dardanelles Straits in Lower Pliocene time, about 4 Ma. We call this zone of deformation the South Marmara Fault (SMF) system and propose that the SMF was then a branch of the dextral North Anatolian Fault. This branch passed to the north of the Marmara Island Eocene block and thus had a south-facing concavity. This curvature resulted in a significant component of shortening in the western part of the fault. The SMF was deactivated at the end of Lower Pliocene, about 3.5 Ma, except for its easternmost branch between the Gulf of Gemlik and ?mral? Island where about 5 mm/year of dextral motion is still occurring today.

Le Pichon, Xavier; ?mren, Caner; Rangin, Claude; ?engör, A. M. Celâl; Siyako, Muzaffer

2014-01-01

180

Seismic Hazard and Fault Length  

NASA Astrophysics Data System (ADS)

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 southern California. Then we compared our mx values with those proposed by CALTRANS, and those assumed in the 2002 USGS/CGS hazard model. To calculate the planning magnitude mp we assumed a truncated Gutenberg-Richter magnitude distribution with parameters a, b, and mx. We fixed b and solved for the a-value in terms of mx, b, and the tectonic moment rate. For many faults mp is relatively insensitive to mx and typically falls off at higher magnitudes because the a-value decreases with increasing mx when the moment rate is constrained. Furthermore, we find that by increasing mx the cumulative earthquake rate actually decreases for smaller magnitude (5 and 6) events. This suggests that fewer magnitude 5 and 6 earthquakes are required to balance the moment budget if larger, but highly infrequent, earthquakes are allowed to occur.

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

2005-12-01

181

The San Andreas Fault 'Supersite' (Invited)  

NASA Astrophysics Data System (ADS)

An expanded and permanent Supersite has been proposed to the Committee on Earth Observation Satellites (CEOS) for the San Andreas Fault system, based upon the successful initial Group on Earth Observations (GEO) Geohazard Supersite for the Los Angeles region from 2009-2013. As justification for the comprehensive San Andreas Supersite, consider the earthquake history of California, in particular the devastating M 7.8 San Francisco earthquake of 1906, which occurred along the San Andreas Fault, as did an earthquake of similar magnitude in 1857 in southern California. Los Angeles was only a small town then, but now the risk exposure has increased for both of California's megacities. Between the San Francisco and Los Angeles urban areas lies a section of the San Andreas Fault known to creep continually, so it has relatively less earthquake hazard. It used to be thought of as capable of stopping earthquakes entering it from either direction. Transitional behavior at either end of the creeping section is known to display a full range of seismic to aseismic slip events and accompanying seismicity and strain transient events. Because the occurrence of creep events is well documented by instrumental networks such as CISN and PBO, the San Andreas Supersite can be expected to be especially effective. A good baseline level of geodetic data regarding past events and strain accumulation and release exists. Many prior publications regarding the occurrence of geophysical phenomena along the San Andreas Fault system mean that in order to make novel contributions, state-of-the-art science will be required within this Supersite region. In more recent years, the 1989 Loma Prieta earthquake struck adjacent to the San Andreas Fault and caused the most damage along the western side of the San Francisco Bay Area. More recently, the concern has focused on the potential for future events along the Hayward Fault along the eastern side of San Francisco Bay. In Southern California, earthquakes struck in 1992 (Landers), 1994 (Northridge) and 1999 (Hector Mine) as well as the 2010 El Mayor - Cucapah (EM-C) earthquake (just south of the US-Mexico border). Of these four notable events, all produced extensive surface faulting except for the 1994 Northridge event, which was close to the Los Angeles urban area on a buried thrust fault. Northridge caused by far the most destruction, topping $20B (US) and resulting in 57 fatalities due to its location under an urban area. The Landers, Hector Mine and EM-C events occurred in desert areas away from major urban centers, and each proved to be a new and unique test-bed for making rapid progress in earthquake science and creative use of geodetic imagery. InSAR studies were linked to GPS deformation and mapping of surface ruptures and seismicity in a series of important papers about these earthquakes. The hazard in California remains extremely high, with tens of millions of people living in close proximity to the San Andreas Fault system as it runs past both San Francisco and Los Angeles. Dense in-situ networks of seismic and geodetic instruments are continually used for research and earthquake monitoring, as well as development of an earthquake early warning capability. Principles of peer review from funding agencies and open data availability will be observed for all data. For all of these reasons, the San Andreas Fault system is highly appropriate for consideration as a world-class permanent Supersite in the GEO framework.

Hudnut, K. W.

2013-12-01

182

Dynamics of fault interaction - Parallel strike-slip faults  

Microsoft Academic Search

We use a 2D finite difference computer program to study the effect of fault steps on dynamic ruptures. Our results indicate that a strike-slip earthquake is unlikely to jump a fault step wider than 5 km, in correlation with field observations of moderate to great-sized earthquakes. We also find that dynamically propagating ruptures can jump both compressional and dilational fault

Ruth A. Harris; Steven M. Day

1993-01-01

183

Hurricane Bonnie Dissolving Crystal Cathedral  

NSDL National Science Digital Library

A fly in to a set of nested 3D isosurfaces of constant precipitation density for Hurricane Bonnie, measured by TRMM on August 22, 1998. The isosurfaces a removed one-by-one until only the highest density surface remains, then the surfaces are restored in reverse order.

Bridgman, Tom; Adler, Robert

2000-09-05

184

Internal structure, fault rocks, and inferences regarding deformation, fluid flow, and mineralization in the seismogenic Stillwater normal fault, Dixie Valley, Nevada  

USGS Publications Warehouse

Outcrop mapping and fault-rock characterization of the Stillwater normal fault zone in Dixie Valley, Nevada are used to document and interpret ancient hydrothermal fluid flow and its possible relationship to seismic deformation. The fault zone is composed of distinct structural and hydrogeological components. Previous work on the fault rocks is extended to the map scale where a distinctive fault core shows a spectrum of different fault-related breccias. These include predominantly clast-supported breccias with angular clasts that are cut by zones containing breccias with rounded clasts that are also clast supported. These are further cut by breccias that are predominantly matrix supported with angular and rounded clasts. The fault-core breccias are surrounded by a heterogeneously fractured damage zone. Breccias are bounded between major, silicified slip surfaces, forming large pod-like structures, systematically oriented with long axes parallel to slip. Matrix-supported breccias have multiply brecciated, angular and rounded clasts revealing episodic deformation and fluid flow. These breccias have a quartz-rich matrix with microcrystalline anhedral, equant, and pervasively conformable mosaic texture. The breccia pods are interpreted to have formed by decompression boiling and rapid precipitation of hydrothermal fluids whose flow was induced by coseismic, hybrid dilatant-shear deformation and hydraulic connection to a geothermal reservoir. The addition of hydrothermal silica cement localized in the core at the map scale causes fault-zone widening, local sealing, and mechanical heterogeneities that impact the evolution of the fault zone throughout the seismic cycle. ?? 2010.

Caine, J. S.; Bruhn, R. L.; Forster, C. B.

2010-01-01

185

Fault management for data systems  

NASA Technical Reports Server (NTRS)

Issues related to automating the process of fault management (fault diagnosis and response) for data management systems are considered. Substantial benefits are to be gained by successful automation of this process, particularly for large, complex systems. The use of graph-based models to develop a computer assisted fault management system is advocated. The general problem is described and the motivation behind choosing graph-based models over other approaches for developing fault diagnosis computer programs is outlined. Some existing work in the area of graph-based fault diagnosis is reviewed, and a new fault management method which was developed from existing methods is offered. Our method is applied to an automatic telescope system intended as a prototype for future lunar telescope programs. Finally, an application of our method to general data management systems is described.

Boyd, Mark A.; Iverson, David L.; Patterson-Hine, F. Ann

1993-01-01

186

Software Evolution and the Fault Process  

NASA Technical Reports Server (NTRS)

In developing a software system, we would like to estimate the way in which the fault content changes during its development, as well determine the locations having the highest concentration of faults. In the phases prior to test, however, there may be very little direct information regarding the number and location of faults. This lack of direct information requires developing a fault surrogate from which the number of faults and their location can be estimated. We develop a fault surrogate based on changes in the fault index, a synthetic measure which has been successfully used as a fault surrogate in previous work. We show that changes in the fault index can be used to estimate the rates at which faults are inserted into a system between successive revisions. We can then continuously monitor the total number of faults inserted into a system, the residual fault content, and identify those portions of a system requiring the application of additional fault detection and removal resources.

Nikora, Allen P.; Munson, John C.

1999-01-01

187

Fault trees and sequence dependencies  

Microsoft Academic Search

One of the frequency cited shortcomings of fault-tree models, their inability to model so-called sequence dependencies, is discussed. Several sources of such sequence dependencies are discussed, and new fault-tree gates to capture this behavior are defined. These complex behaviors can be included in present fault-tree models because they utilize a Markov solution. The utility of the new gates is demonstrated

Joanne Bechta Dugan; Salvatore J. Bavuso; Mark A. Boyd

1990-01-01

188

Compositional Temporal Fault Tree Analysis  

Microsoft Academic Search

HiP-HOPS (Hierarchically-Performed Hazard Origin and Propaga- tion Studies) is a recent technique that partly automates Fault Tree Analysis (FTA) by constructing fault trees from system topologies annotated with component-level failure specifications. HiP-HOPS has hitherto created only classical combinatorial fault trees that fail to capture the often significant temporal ordering of failure events. In this paper, we propose temporal extensions to

Martin Walker; Leonardo Bottaci; Yiannis Papadopoulos

2007-01-01

189

Handling Software Faults with Redundancy  

Microsoft Academic Search

Software engineering methods can increase the dependability of software systems, and yet some faults escape even the most\\u000a rigorous and methodical development process. Therefore, to guarantee high levels of reliability in the presence of faults,\\u000a software systems must be designed to reduce the impact of the failures caused by such faults, for example by deploying techniques\\u000a to detect and compensate

Antonio Carzaniga; Alessandra Gorla; Mauro Pezzè

2008-01-01

190

Software Fault Tolerance in the Application Layer  

Microsoft Academic Search

By software fault tolerance in the application layer, we mean a set of application level software components to detect and recover from faults that are not handled in the hardware or operating system layers of a computer system. We consider those faults that cause an application process to crash or hang; they include application software faults as well as faults

Yennun Huang

1995-01-01

191

Multiple Fault Diagnosis in Combinational Networks.  

National Technical Information Service (NTIS)

A new concept, the prime fault, is introduced for the study of multiple fault diagnosis in combinational logic networks. It is shown that every multiple fault in a network can be represented by a functionally equivalent fault with prime faults as its only...

C. W. Y. Cha

1974-01-01

192

Experimental Fault Reactivation on Favourably and Unfavourably Oriented Faults  

NASA Astrophysics Data System (ADS)

In this study, we introduce work which aims assess the loading of faults to failure under different stress regimes in a triaxial deformation apparatus. We explore experimentally the reshear of an existing fault in various orientations for particular values of (?1 - ?3) and ?3' for contrasting loading systems - load-strengthening (equivalent to a thrust fault) with ?1' increasing at constant ?3', versus load-weakening (equivalent to a normal fault) with reducing ?3' under constant ?1'. Experiments are conducted on sawcut granite samples with fault angles at a variety of orientations relative to ?1 , ranging from an optimal orientation for reactivation to lockup angles where new faults are formed in preference to reactivating the existing sawcut orientation. Prefailure and postfailure behaviour is compared in terms of damage zone development via monitoring variations in ultrasonic velocity and acoustic emission behaviour. For example, damage surrounding unfavourably oriented faults is significantly higher than that seen around favourably orientated faults due to greater maximum stresses attained prior to unstable slip, which is reflected by the increased acoustic emission activity leading up to failure. In addition, we also experimentally explore the reshear of natural pseudotachylytes (PSTs) from two different fault zones; the Gole Larghe Fault, Adamello, Italy in which the PSTs are in relatively isotropic Tonalite (at lab sample scale) and the Alpine Fault, New Zealand in which the PSTs are in highly anisotropic foliated shist. We test whether PSTs will reshear in both rock types under the right conditions, or whether new fractures in the wall rock will form in preference to reactivating the PST (PST shear strength is higher than that of the host rock). Are PSTs representative of one slip event?

Mitchell, T. M.; Sibson, R. H.; Renner, J.; Toy, V. G.; di Toro, G.; Smith, S. A.

2010-12-01

193

Fault trees and sequence dependencies  

NASA Technical Reports Server (NTRS)

One of the frequently cited shortcomings of fault-tree models, their inability to model so-called sequence dependencies, is discussed. Several sources of such sequence dependencies are discussed, and new fault-tree gates to capture this behavior are defined. These complex behaviors can be included in present fault-tree models because they utilize a Markov solution. The utility of the new gates is demonstrated by presenting several models of the fault-tolerant parallel processor, which include both hot and cold spares.

Dugan, Joanne Bechta; Boyd, Mark A.; Bavuso, Salvatore J.

1990-01-01

194

Fault-tolerant processing system  

NASA Technical Reports Server (NTRS)

A fault-tolerant, fiber optic interconnect, or backplane, which serves as a via for data transfer between modules. Fault tolerance algorithms are embedded in the backplane by dividing the backplane into a read bus and a write bus and placing a redundancy management unit (RMU) between the read bus and the write bus so that all data transmitted by the write bus is subjected to the fault tolerance algorithms before the data is passed for distribution to the read bus. The RMU provides both backplane control and fault tolerance.

Palumbo, Daniel L. (Inventor)

1996-01-01

195

Overview of the Southern San Andreas Fault Model  

USGS Publications Warehouse

This appendix summarizes the data and methodology used to generate the source model for the southern San Andreas fault. It is organized into three sections, 1) a section by section review of the geological data in the format of past Working Groups, 2) an overview of the rupture model, and 3) a manuscript by Biasi and Weldon (in review Bulletin of the Seismological Society of America) that describes the correlation methodology that was used to help develop the ?geologic insight? model. The goal of the Biasi and Weldon methodology is to quantify the insight that went into developing all A faults; as such it is in concept consistent with all other A faults but applied in a more quantitative way. The most rapidly slipping fault and the only known source of M~8 earthquakes in southern California is the San Andreas fault. As such it plays a special role in the seismic hazard of California, and has received special attention in the current Working Group. The underlying philosophy of the current Working Group is to model the recurrence behavior of large, rapidly slipping faults like the San Andreas from observed data on the size, distribution and timing of past earthquakes with as few assumptions about underlying recurrence behavior as possible. In addition, we wish to carry the uncertainties in the data and the range of reasonable extrapolations from the data to the final model. To accomplish this for the Southern San Andreas fault we have developed an objective method to combine all of the observations of size, timing, and distribution of past earthquakes into a comprehensive set of earthquake scenarios that each represent a possible history of earthquakes for the past ~1400 years. The scenarios are then ranked according to their overall consistency with the data and then the frequencies of all of the ruptures permitted by the current Working Group?s segmentation model are calculated. We also present 30-yr conditional probabilities by segment and compare to previous results. A distinctive aspect of the current model is that the probability is higher at both ends of the fault and that the ends have a much greater fraction of smaller events. There is a significant difference in the likelihood of large (M 7.7-8.0) earthquakes along the fault from north to south, with large 1857-like events common on the northern half of the southern San Andreas fault but relatively few M 7.7-8.0 expected on the southern half.

Weldon, Ray J., II; Biasi, Glenn P.; Wills, Chris J.; Dawson, Timothy E.

2008-01-01

196

A survey of an introduction to fault diagnosis algorithms  

NASA Technical Reports Server (NTRS)

This report surveys the field of diagnosis and introduces some of the key algorithms and heuristics currently in use. Fault diagnosis is an important and a rapidly growing discipline. This is important in the design of self-repairable computers because the present diagnosis resolution of its fault-tolerant computer is limited to a functional unit or processor. Better resolution is necessary before failed units can become partially reuseable. The approach that holds the greatest promise is that of resident microdiagnostics; however, that presupposes a microprogrammable architecture for the computer being self-diagnosed. The presentation is tutorial and contains examples. An extensive bibliography of some 220 entries is included.

Mathur, F. P.

1972-01-01

197

Perspective View, Garlock Fault  

NASA Technical Reports Server (NTRS)

California's Garlock Fault, marking the northwestern boundary of the Mojave Desert, lies at the foot of the mountains, running from the lower right to the top center of this image, which was created with data from NASA's shuttle Radar Topography Mission (SRTM), flown in February 2000. The data will be used by geologists studying fault dynamics and landforms resulting from active tectonics. These mountains are the southern end of the Sierra Nevada and the prominent canyon emerging at the lower right is Lone Tree canyon. In the distance, the San Gabriel Mountains cut across from the leftside of the image. At their base lies the San Andreas Fault which meets the Garlock Fault near the left edge at Tejon Pass. The dark linear feature running from lower right to upper left is State Highway 14 leading from the town of Mojave in the distance to Inyokern and the Owens Valley in the north. The lighter parallel lines are dirt roads related to power lines and the Los Angeles Aqueduct which run along the base of the mountains.

This type of display adds the important dimension of elevation to the study of land use and environmental processes as observed in satellite images. The perspective view was created by draping a Landsat satellite image over an SRTM elevation model. Topography is exaggerated 1.5 times vertically. The Landsat image was provided by the United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota.

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC.

Size: Varies in a perspective view Location: 35.25 deg. North lat., 118.05 deg. West lon. Orientation: Looking southwest Original Data Resolution: SRTM and Landsat: 30 meters (99 feet) Date Acquired: February 16, 2000

2000-01-01

198

Computer system isolates faults  

SciTech Connect

Maintaining transaction processing systems in continuous operation, a minicomputer system made by tolerant systems detects and isolates faults, then transfers work loads to the appropriate backup resource. An eternity system is actually 1 to 15 computer systems, called system building blocks, interconnected by a communication network. Modularity is provided by tolerant's flexible architecture technique. This allows a user to expand system capacity with nondedicated computers which can be assigned to tasks such as increasing processing power, user accessibility and database size as dictated by needs. The loosely-coupled nature of the system increases reliability.

Hall, D.E.

1983-11-01

199

It's All Their Fault?  

PubMed

Many students fail our introductory science courses and give up on science altogether. How much of this is their fault is debatable. But what is not debatable is that we can improve the situation by using active learning methods. Many faculty claim critical thinking is their highest priority. Their teaching seldom reflects this. They emphasize facts and lecture without context. Most of our students are not going to be scientists, but they are going to be citizens and need to be able to spot inaccuracies when they appear in the media. Case-based and Problem-based Teaching are proven ways to achieve this goal. PMID:23653695

Herreid, Clyde Freeman

2010-01-01

200

It's All Their Fault?  

PubMed Central

Many students fail our introductory science courses and give up on science altogether. How much of this is their fault is debatable. But what is not debatable is that we can improve the situation by using active learning methods. Many faculty claim critical thinking is their highest priority. Their teaching seldom reflects this. They emphasize facts and lecture without context. Most of our students are not going to be scientists, but they are going to be citizens and need to be able to spot inaccuracies when they appear in the media. Case-based and Problem-based Teaching are proven ways to achieve this goal.

Herreid, Clyde Freeman

2010-01-01

201

Fault current limiter  

SciTech Connect

A fault current limiter (FCL) includes a series of high permeability posts for collectively define a core for the FCL. A DC coil, for the purposes of saturating a portion of the high permeability posts, surrounds the complete structure outside of an enclosure in the form of a vessel. The vessel contains a dielectric insulation medium. AC coils, for transporting AC current, are wound on insulating formers and electrically interconnected to each other in a manner such that the senses of the magnetic field produced by each AC coil in the corresponding high permeability core are opposing. There are insulation barriers between phases to improve dielectric withstand properties of the dielectric medium.

Darmann, Francis Anthony

2013-10-08

202

Dynamics of earthquake faults  

SciTech Connect

The authors present an overview of ongoing studies of the rich dynamical behavior of the uniform, deterministic Burridge-Knopoff model of an earthquake fault, discussing the model's behavior in the context of current seismology. The topics considered include: (1) basic properties of the model, such as the distinction between small and large events and the magnitude vs frequency distribution; (2) dynamics of individual events, including dynamical selection of rupture propagation speeds; (3) generalizations of the model to more realistic, higher-dimensional models; and (4) studies of predictability, in which artificial catalogs generated by the model are used to test and determine the limitations of pattern recognition algorithms used in seismology.

Carlson, J.M. (Department of Physics and Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)); Langer, J.S. (Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)); Shaw, B.E. (Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States) Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964 (United States))

1994-04-01

203

The load balance on the fault ring based fault-tolerant routing scheme in Tori  

Microsoft Academic Search

In the network of tori with faults, many fault-tolerant routing schemes have been proposed based on the fault models. Although these schemes enable the packets to bypass the fault regions without causing any deadlock in the network, they have the common shortcoming. Since all blocked packets would be misrouted on the fault ring, the fault ring would undertake heavier traffic

Lingfu Xie; Du Xu; Shizhong Xu

2009-01-01

204

A complete algorithm to fault calculation due to simultaneous faults. \\  

Microsoft Academic Search

This paper discusses the great variety of fault types that can arise on a power system. The most important techniques of this paper is the consideration of unequal magnitudes of source EMF and with different phase angles to show their effect on fault analysis and protection of the power system. Furthermore, an algorithm developed for the calculation of simultaneous power

Fathy M. Abouelenin

2002-01-01

205

Fault Branching and Rupture Directivity  

NASA Astrophysics Data System (ADS)

Can the rupture directivity of past earthquakes be inferred from fault geometry? Nakata et al. [J. Geogr., 1998] propose to relate the observed surface branching of fault systems with directivity. Their work assumes that all branches are through acute angles in the direction of rupture propagation. However, in some observed cases rupture paths seem to branch through highly obtuse angles, as if to propagate ``backwards". Field examples of that are as follows: (1) Landers 1992. When crossing from the Johnson Valley to the Homestead Valley (HV) fault via the Kickapoo (Kp) fault, the rupture from Kp progressed not just forward onto the northern stretch of the HV fault, but also backwards, i.e., SSE along the HV [Sowers et al., 1994, Spotila and Sieh, 1995, Zachariasen and Sieh, 1995, Rockwell et al., 2000]. Measurements of surface slip along that backward branch, a prominent feature of 4 km length, show right-lateral slip, decreasing towards the SSE. (2) At a similar crossing from the HV to the Emerson (Em) fault, the rupture progressed backwards along different SSE splays of the Em fault [Zachariasen and Sieh, 1995]. (3). In crossing from the Em to Camp Rock (CR) fault, again, rupture went SSE on the CR fault. (4). Hector Mine 1999. The rupture originated on a buried fault without surface trace [Li et al., 2002; Hauksson et al., 2002] and progressed bilaterally south and north. In the south it met the Lavic Lake (LL) fault and progressed south on it, but also progressed backward, i.e. NNW, along the northern stretch of the LL fault. The angle between the buried fault and the northern LL fault is around -160o, and that NNW stretch extends around 15 km. The field examples with highly obtuse branch angles suggest that there may be no simple correlation between fault geometry and rupture directivity. We propose that an important distinction is whether those obtuse branches actually involved a rupture path which directly turned through the obtuse angle (while continuing also on the main fault), or rather involved arrest by a barrier on the original fault and jumping [Harris and Day, JGR, 1993] to a neighboring fault on which rupture propagated bilaterally to form what appears as a backward-branched structure. Our studies [Poliakov et al., JGR in press, 2002; Kame et al, EOS, 2002] of stress fields around a dynamically moving mode II crack tip show a clear tendency to branch from the straight path at high rupture speeds, but the stress fields never allow the rupture path to directly turn through highly obtuse angles, and hence that mechanism is unlikely. In contrast, study of fault maps in the vicinity of the Kp to HV fault transition [Sowers et al., 1994], discussed as case (1) above, strongly suggest that the large-angle branching occurred as a jump, which we propose as the likely general mechanism. Implications for the Nakata et al. [1998] aim of inferring rupture directivity from branch geometry is that this will be possible only when rather detailed characterization (by surface geology, seismic relocation, trapped waves) of fault connectivity can be carried out in the vicinity of the branching junction, to ascertain whether direct turning of the rupture path through an angle, or jumping and then propagating bilaterally, were involved in prior events. They have opposite implications for how we would associate past directivity with a (nominally) branched fault geometry.

Dmowska, R.; Rice, J. R.; Kame, N.

2002-12-01

206

Central Asia Active Fault Database  

NASA Astrophysics Data System (ADS)

The ongoing collision of the Indian subcontinent with Asia controls active tectonics and seismicity in Central Asia. This motion is accommodated by faults that have historically caused devastating earthquakes and continue to pose serious threats to the population at risk. Despite international and regional efforts to assess seismic hazards in Central Asia, little attention has been given to development of a comprehensive database for active faults in the region. To address this issue and to better understand the distribution and level of seismic hazard in Central Asia, we are developing a publically available database for active faults of Central Asia (including but not limited to Afghanistan, Tajikistan, Kyrgyzstan, northern Pakistan and western China) using ArcGIS. The database is designed to allow users to store, map and query important fault parameters such as fault location, displacement history, rate of movement, and other data relevant to seismic hazard studies including fault trench locations, geochronology constraints, and seismic studies. Data sources integrated into the database include previously published maps and scientific investigations as well as strain rate measurements and historic and recent seismicity. In addition, high resolution Quickbird, Spot, and Aster imagery are used for selected features to locate and measure offset of landforms associated with Quaternary faulting. These features are individually digitized and linked to attribute tables that provide a description for each feature. Preliminary observations include inconsistent and sometimes inaccurate information for faults documented in different studies. For example, the Darvaz-Karakul fault which roughly defines the western margin of the Pamir, has been mapped with differences in location of up to 12 kilometers. The sense of motion for this fault ranges from unknown to thrust and strike-slip in three different studies despite documented left-lateral displacements of Holocene and late Pleistocene landforms observed near the fault trace.

Mohadjer, Solmaz; Ehlers, Todd A.; Kakar, Najibullah

2014-05-01

207

Developing a Knowledge-Based System Using Rough Set Theory and Genetic Algorithms for Substation Fault Diagnosis  

Microsoft Academic Search

Supervisory Control and Data Acquisition (SCADA) systems are fundamental tools for quick fault diagnosis and efficient restoration\\u000a of power systems. When multiple faults, or malfunctions of protection devices occur in the system, the SCADA system issues\\u000a many alarm signals rapidly and relays these to the control center. The original cause and location of the fault can be difficult\\u000a to determine

Ching Lai Hor; Peter Crossley; Simon Watson; Dean Millar

208

SFT: Scalable Fault Tolerance  

SciTech Connect

In this paper we will present a new technology that we are currently developing within the SFT: Scalable Fault Tolerance FastOS project which seeks to implement fault tolerance at the operating system level. Major design goals include dynamic reallocation of resources to allow continuing execution in the presence of hardware failures, very high scalability, high efficiency (low overhead), and transparency—requiring no changes to user applications. Our technology is based on a global coordination mechanism, that enforces transparent recovery lines in the system, and TICK, a lightweight, incremental checkpointing software architecture implemented as a Linux kernel module. TICK is completely user-transparent and does not require any changes to user code or system libraries; it is highly responsive: an interrupt, such as a timer interrupt, can trigger a checkpoint in as little as 2.5?s; and it supports incremental and full checkpoints with minimal overhead—less than 6% with full checkpointing to disk performed as frequently as once per minute.

Petrini, Fabrizio; Nieplocha, Jarek; Tipparaju, Vinod

2006-04-15

209

Software fault injection for survivability  

Microsoft Academic Search

In this paper, we present an approach and experimental results from using software fault injection to assess information survivability. We define information survivability to mean the ability of an information system to continue to operate in the presence of faults, anomalous system behavior, or malicious attack. In the past, finding and removing software flaws has traditionally been the realm of

J. M. Voas; A. K. Ghosh

2000-01-01

210

Fault Injection for the Masses  

Microsoft Academic Search

The key technology that the author would like to see adopted by the masses is a family of software fault injection algorithms that can predict where to concentrate testing. From a novelty standpoint, these algorithms were (and still are) unique among other methods of performing fault injection. The author concedes that the algorithms are computational, but the results can provide

Jeffrey M. Voas

1997-01-01

211

Fault trees and imperfect coverage  

Microsoft Academic Search

A new algorithm is presented for solving the fault tree. The algorithm includes the dynamic behavior of the fault\\/error handling model but obviates the need for the Markov chain solution. As the state space is expanded in a breadth-first search (the same is done in the conversion to a Markov chain), the state's contribution to each future state is calculated

Joanne Bechta Dugan

1989-01-01

212

Surface Creep on California Faults  

NSDL National Science Digital Library

This site provides data from a number of creepmeters in California. A creepmeter is an instrument that monitors the slow surface displacement of an active fault. Its function is not to measure fault slip during earthquakes, but to record the slow aseismic slip between earthquakes.

Bilham, Roger; Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado

213

JPL Fault Protection Software Experiences  

NASA Technical Reports Server (NTRS)

This objectives of this slide presentation are to: (1) Share JPL experiences by describing the evolution of fault protection during its history in deep space exploration, (2) Examine issues of fault protection scope and implementation that affect missions today, and (3) Discuss solutions for the problems of today and tomorrow.

Barltrop, Kevin; Dvorak, Dan

2008-01-01

214

Real-Time Fault Diagnostics  

Microsoft Academic Search

The intelligent process control system (IPCS), an integrated environment for developing complex process control and automation systems is discussed, focusing on its real-time fault diagnostics capability. IPCS has been used to build a supervisory monitoring and diagnostics system for a cogenerator plant. The requirements and problems specific to such systems are examined. The key concepts involved in fault modeling in

Samir Padalkar; Gabor Karsai; Csaba Biegl; Janos Sztipanovits; Koji Okuda; Nobuji Miyasaka

1991-01-01

215

Accelerometer having integral fault null  

NASA Technical Reports Server (NTRS)

An improved accelerometer is introduced. It comprises a transducer responsive to vibration in machinery which produces an electrical signal related to the magnitude and frequency of the vibration; and a decoding circuit responsive to the transducer signal which produces a first fault signal to produce a second fault signal in which ground shift effects are nullified.

Bozeman, Richard J., Jr. (inventor)

1995-01-01

216

RADIOGENIC ARGON AND STRONTIUM DIFFUSION PARAMETERS IN BIOTITE AT LOW TEMPERATURES OBTAINED FROM ALPINE FAULT UPLIFT IN NEW ZEALAND  

Microsoft Academic Search

Rapid uplift along the Alpine Fault zone in New Zealand exposed ancient ; mica schists which are estimated to have been at depths up to 9000 ft prior to ; the fault displacement, on the assumption that the smooth surface represented by ; the present, flat topped, peak elevations is truly representative of the mature ; Pliocene surface prior to

P. M. Hurley; H. Hughes; W. H. Jr. Pinson; H. W. Fairbairn

1962-01-01

217

Localization of listric faults at thrust fault ramps beneath the Great Salt Lake Basin, Utah: Evidence from seismic imaging and finite element modeling  

NASA Astrophysics Data System (ADS)

Reflection seismic data from the Great Salt Lake Basin, Utah, show that the major basin-bounding normal faults decrease in dip from ˜60° at the surface to ˜10°-20° at depths as shallow as 4-6 km. This rapid decrease in fault dip at depths shallower than the brittle-ductile transition zone in the Basin and Range Province suggests an explanation other than a gradual change of rheology and stress orientations with depth. Using a dense grid of seismic data, gravity data, borehole data, and published geologic information from islands in the lake, we constrain the position of the Sevier age Willard thrust and a footwall imbricate and show their reactivation as normal faults during Tertiary extension. In the absence of surface geologic information, we use available subsurface information from the lake to draw an analogy with the Ogden duplex in the Wasatch Front, where Cenozoic normal faulting was superimposed on an earlier Sevier age thrust regime to give rise to listric normal faults. Our interpretations are consistent with finite element modeling results, which demonstrate that extensional slip on preexisting thrust ramps leads to the formation of energetically favored synthetic normal faults, some of which may merge with the thrust ramp and obtain listric geometries. Further slip on these listric faults gives rise to secondary synthetic and antithetic faults resulting in hanging wall grabens.

Mohapatra, Gopal K.; Johnson, Roy A.

1998-05-01

218

Tectonic development of the Alpine fault zone, New Zealand: a fission-track study  

SciTech Connect

Fission-track dating of zircons from the Alpine fault zone in New Zealand and associated granites and gneisses reveals at least three stages in the development of the present fault zone. Mylonites northwest of the Fraser fault give ages of ca 80 Ma. Zircons from the Fraser Formation, bounded by the Fraser and Alpine faults, give ages of ca 9 Ma. Samples east of the Alpine fault give ages below 5 Ma. These youngest ages result from the currently active uplift of the Alpine schists against the Alpine fault. The 9 ma ages record a rapid uplift of the Fraser Formation owing to the onset of compression across the plate boundary. Mylonites to the west of the mapped Fraser fault that give zircon fission-track ages of ca 80 Ma indicate a third, much earlier phase of fault movement. Structural and other geologic evidence supports these conclusions. The observation that the present plate boundary was located along a preexisting zone of weakness suggests that mylonite zones may merit greater attention as possible sites for initiation of rifting and/or continental transform faults. 26 references.

White, S.H.; Green, P.F.

1986-02-01

219

Arc fault detection system  

DOEpatents

An arc fault 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 located 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 located between the switchboard and a power supply to remove the supply of power to the switchboard.

Jha, Kamal N. (Bethel Park, PA)

1999-01-01

220

Fault Tolerant Cache Schemes  

NASA Astrophysics Data System (ADS)

Most of modern microprocessors employ on—chip cache memories to meet the memory bandwidth demand. These caches are now occupying a greater real es tate of chip area. Also, continuous down scaling of transistors increases the possi bility of defects in the cache area which already starts to occupies more than 50% of chip area. For this reason, various techniques have been proposed to tolerate defects in cache blocks. These techniques can be classified into three different cat egories, namely, cache line disabling, replacement with spare block, and decoder reconfiguration without spare blocks. This chapter examines each of those fault tol erant techniques with a fixed typical size and organization of L1 cache, through extended simulation using SPEC2000 benchmark on individual techniques. The de sign and characteristics of each technique are summarized with a view to evaluate the scheme. We then present our simulation results and comparative study of the three different methods.

Tu, H.-Yu.; Tasneem, Sarah

221

Improving Multiple Fault Diagnosability using Possible Conflicts  

NASA Technical Reports Server (NTRS)

Multiple fault diagnosis is a difficult problem for dynamic systems. Due to fault masking, compensation, and relative time of fault occurrence, multiple faults can manifest in many different ways as observable fault signature sequences. This decreases diagnosability of multiple faults, and therefore leads to a loss in effectiveness of the fault isolation step. We develop a qualitative, event-based, multiple fault isolation framework, and derive several notions of multiple fault diagnosability. We show that using Possible Conflicts, a model decomposition technique that decouples faults from residuals, we can significantly improve the diagnosability of multiple faults compared to an approach using a single global model. We demonstrate these concepts and provide results using a multi-tank system as a case study.

Daigle, Matthew J.; Bregon, Anibal; Biswas, Gautam; Koutsoukos, Xenofon; Pulido, Belarmino

2012-01-01

222

The continuity of active fault systems in Greece  

NASA Astrophysics Data System (ADS)

Evidence from geomorphology, the distribution of large earthquakes, and geodetic measurements suggests that the active faulting in mainland Greece and the north Aegean Sea is concentrated into a small number of discrete, linear zones that bound relatively rigid blocks. On land, the zones are most clearly identified where the faulting is associated with large escarpments, particularly in hard footwall rocks. The zones can become indistinct and diffuse near their ends, sometimes because they enter high, unstable topography where landsliding obscures the fault morphology, but mostly because the extension rates decrease along strike as a consequence of the relative rotation of the blocks they bound. The main graben systems of Chalkidiki, southern Thessaly and the North Gulf of Evia all seem to connect with the strike-slip faulting in the offshore Aegean and to die out in the west, a configuration related to clockwise rotations in east-central Greece. By contrast, the Gulf of Corinth, which is the fastest opening graben system in Greece, opens more rapidly in the west than the east. Both these features of the Gulf of Corinth are consequences of the motion of the south Aegean and Peloponnese as a single block. Late Pliocene and Quaternary geology and geomorphology indicate that the boundaries of the rigid blocks in central Greece have changed over that time, with faulting migrating into the hanging walls, sometimes changing in orientation. These changes are probably related to the way faulting in the seismogenic layer adapts to block rotation, so as to maintain the general features of a velocity field that is controlled by larger scale effects, such as buoyancy forces and the seaward migration of the subducting slab beneath Crete. The image of Greece as a mosaic of rigid blocks whose boundaries change with time is a useful framework for seismic hazard evaluation, but we emphasize that some moderate-sized earthquakes do occur away from the main fault zones, within the relatively rigid blocks and especially near their diffuse ends.

Goldsworthy, Mary; Jackson, James; Haines, John

2002-03-01

223

The Continuity of Active Fault Systems in Greece  

NASA Astrophysics Data System (ADS)

Evidence from geomorphology, the distribution of large earthquakes, and geodetic measurements suggests that the active faulting in mainland Greece and the north Aegean Sea is concentrated into a small number of discrete, linear zones that bound relatively rigid blocks. On land, the zones are most clearly identified where the faulting is associated with large escarpments, particularly in hard footwall rocks. The zones can become indistinct and diffuse near their ends, sometimes because they enter high, unstable topography where landsliding obscures the fault morphology, but mostly because the extension rates decrease along strike as a consequence of the relative rotation of the blocks they bound. The main graben systems of Chalkidiki, southern Thessaly and the North Gulf of Evia all seem to connect with the strike-slip faulting in the offshore Aegean and to die out in the west, a configuration related to clockwise rotations in east-central Greece. By contrast, the Gulf of Corinth, which is the fastest opening graben system in Greece, opens more rapidly in the west than the east. Both of these features are consequences of the motion of the south Aegean and Peloponnese as a single block. Late Pliocene and Quaternary geology and geomorphology indicate that the boundaries of the rigid blocks in central Greece have changed over that time, with faulting migrating into the hanging walls, sometimes changing in orientation. These changes are probably related to the way faulting in the seismogenic layer adapts to block rotation, so as to maintain the general features of a velocity field that is controlled by larger scale effects, such as buoyancy forces and the seaward migration of the subducting slab beneath Crete. The image of Greece as a mosaic of rigid blocks whose boundaries change with time is a useful framework for seismic hazard evaluation, but we emphasize that some moderate-sized earthquakes do occur away from the main fault zones, within the relatively rigid blocks and especially near their diffuse ends.

Goldsworthy, M.; Jackson, J.; Haines, J.

2001-12-01

224

Populations of faults and fault displacements and their effects on estimates of fault-related regional extension  

NASA Astrophysics Data System (ADS)

Measured populations of fault displacements, derived from regional seismic, oilfield seismic, coalmine plans and outcrop data show a power law distribution with exponents (- S) of -0.45 to -0.95 for singleline samples across an array of faults. The more negative values indicate relatively larger numbers of smaller faults. An expression for a population of active faults, derived from the Gutenberg-Richter magnitude-frequency relation for earthquakes, is log N = a - bD log D, where D = maximum displacement of a fault, N = number of faults of maximum displacement D or greater, and b D ? 1.0 and has the same value as b for the corresponding earthquake population. Populations of 'dead' faults existing at the end of a tectonic episode have been numerically derived, using a fault growth model, and satisfy the relation log N = a - E log D where E has a value between 1.6 and 2.0. Numerically derived populations of fault displacements in a dead fault population have slopes of - S where S = E - 1. The contribution of an individual fault to the regional strain varies with the lifetime seismic moment of the fault and is proportional to D2. Estimation of fault-related extension by summing heaves on faults of a limited size range is valid only if the measured size range of faults accommodates most of the extension. Correction can be made if the S value of the fault displacement population is known.

Walsh, J. J.; Watterson, J.

1992-06-01

225

Relationship between Bouguer anomaly and active fault ( source fault) - For the purpose of estimate of source fault -  

Microsoft Academic Search

Concepts of setting source fault parameters from active faults are discussed for predictions of strong ground motion. Estimation of ground motion plays important rule for the prevention of earthquake hazards. From recent developments in waveform inversion analysis of source fault rupture processes through large earthquakes, it is found that strong ground motion is strongly affected by fault geometry and slip

N. Kitada; N. Inoue; K. Takemura

2008-01-01

226

Hayward Fault rate constraints at Berkeley: Evaluation of the 335-meter Strawberry Creek offset  

NASA Astrophysics Data System (ADS)

At UC Berkeley the active channel of Strawberry Creek is offset 335 meters by the Hayward fault and two abandoned channels of Strawberry Creek are laterally offset 580 and 730 meters. These relationships record the displacement of the northern Hayward fault at Berkeley over a period of tens of millennia. The Strawberry Creek site has a similar geometry to the central San Andreas fault's Wallace Creek site, which arguably provides the best geological evidence of "millennial" fault kinematics in California (Sieh and Jahns, 1984). Slip rate determinations are an essential component of overall hazard evaluation for the Hayward fault, and this site is ripe to disclose a long-term form of this parameter, to contrast with geodetic and other geological rate evidence. Large offsets at the site may lower uncertainty in the rate equation relative to younger sites, as the affect of stream abandonment age, generally the greatest source of rate uncertainty, is greatly reduced. This is helpful here because it more-than-offsets uncertainties resulting from piercing projections to the fault. Strawberry Creek and its ancestral channels suggest west-side-up vertical deformation across the Hayward fault at this location. The development of the vertical deformation parameter will complement ongoing geodetic measurements, particularly InSAR, and motivate testing of other geological constraints. Up-to-the-west motion across the Hayward fault at Berkeley has important implications for the partitioning of strain and kinematics of the northern Hayward fault, and may explain anomalous up-on-the-west landforms elsewhere along the fault. For example, geological features of the western Berkeley Hills are consistent with rapid and recent uplift to the west of the fault. On the basis of a preliminary analysis of the offset channels of Strawberry Creek, up-to-the-west uplift is about 0.5mm/yr across the Hayward fault at Berkeley. If this is in fact the long-term rate, the 150 m height of the Hills to the northwest of the Strawberry Creek site was produced during the past about 300,000 years by a significant dip- slip (thrust) component of Hayward fault motion. Rapid and recent uplift of some portions of the East Bay Hills has important implications for fault geometries and slope stability, and should strongly influence the investigation fault hazards in areas that are more complexly deformed.

Williams, P. L.

2007-12-01

227

Crystal fractionation in the friction melts of seismic faults (Alpine Fault, New Zealand)  

NASA Astrophysics Data System (ADS)

Compositional variations are documented in friction melts along the Hari Hari section of the Alpine Fault, New Zealand, with multiple stages of melt injection into quartzo-feldspathic schists. Intermediate to felsic melts were heterogeneous in composition, but all fractions show a common trend, with a tendency for the younger melt layers and glasses to be more alkali - (Na + K) and Si-enriched, while being depleted in mafic (Fe + Mg + Mn) components. These changes are attributed primarily to crystal fractionation of the melt during transport. Farther traveled molten layers were on the whole less viscous, mostly due to a higher melt-to-clast ratio; however, compositional change, together with a decrease in volatile content, produced a progressively more viscous liquid melt with time. The glass phase is interpreted as a remnant of this high viscosity felsic residual melt that was preserved during final quenching. Following initial failure, the formation of largely phyllosilicate-derived, volatile-rich, lower viscosity melt corresponds with a phase of fault weakening. Subsequent rapid crystal fractionation during melt transport, the loss of volatiles and freezing of residual melt contributed to the strengthening of the fault during seismic slip.

Warr, Laurence N.; van der Pluijm, Ben A.

2005-06-01

228

Fault Injection Campaign for a Fault Tolerant Duplex Framework  

NASA Technical Reports Server (NTRS)

Fault tolerance is an efficient approach adopted to avoid or reduce the damage of a system failure. In this work we present the results of a fault injection campaign we conducted on the Duplex Framework (DF). The DF is a software developed by the UCLA group [1, 2] that uses a fault tolerant approach and allows to run two replicas of the same process on two different nodes of a commercial off-the-shelf (COTS) computer cluster. A third process running on a different node, constantly monitors the results computed by the two replicas, and eventually restarts the two replica processes if an inconsistency in their computation is detected. This approach is very cost efficient and can be adopted to control processes on spacecrafts where the fault rate produced by cosmic rays is not very high.

Sacco, Gian Franco; Ferraro, Robert D.; von llmen, Paul; Rennels, Dave A.

2007-01-01

229

Method of locating ground faults  

NASA Technical Reports Server (NTRS)

The present invention discloses a method of detecting and locating current imbalances such as ground faults in multiwire systems using the Faraday effect. As an example, for 2-wire or 3-wire (1 ground wire) electrical systems, light is transmitted along an optical path which is exposed to magnetic fields produced by currents flowing in the hot and neutral wires. The rotations produced by these two magnetic fields cancel each other, therefore light on the optical path does not read the effect of either. However, when a ground fault occurs, the optical path is exposed to a net Faraday effect rotation due to the current imbalance thereby exposing the ground fault.

Patterson, Richard L. (inventor); Rose, Allen H. (inventor); Cull, Ronald C. (inventor)

1994-01-01

230

Fault-free performance validation of fault-tolerant multiprocessors  

NASA Technical Reports Server (NTRS)

A validation methodology for testing the performance of fault-tolerant computer systems was developed and applied to the Fault-Tolerant Multiprocessor (FTMP) at NASA-Langley's AIRLAB facility. This methodology was claimed to be general enough to apply to any ultrareliable computer system. The goal of this research was to extend the validation methodology and to demonstrate the robustness of the validation methodology by its more extensive application to NASA's Fault-Tolerant Multiprocessor System (FTMP) and to the Software Implemented Fault-Tolerance (SIFT) Computer System. Furthermore, the performance of these two multiprocessors was compared by conducting similar experiments. An analysis of the results shows high level language instruction execution times for both SIFT and FTMP were consistent and predictable, with SIFT having greater throughput. At the operating system level, FTMP consumes 60% of the throughput for its real-time dispatcher and 5% on fault-handling tasks. In contrast, SIFT consumes 16% of its throughput for the dispatcher, but consumes 66% in fault-handling software overhead.

Czeck, Edward W.; Feather, Frank E.; Grizzaffi, Ann Marie; Segall, Zary Z.; Siewiorek, Daniel P.

1987-01-01

231

Ground-Fault Feeder Detection With Fault-Current and Fault-Resistance Measurement in Mine Power Systems  

Microsoft Academic Search

Many mine power systems operate with a floating neutral or are high-resistance grounded, and earth fault current is no more than a few tens of amperes. Traditional earth-fault-detection methods based on zero-sequence current have poor sensitivity in this case. For improvement, a fault-detection scheme with fault-current and fault-resistance measurement is presented in this paper, which is capable of detecting high-impedance

Xiangjun Zeng; K. K. Li; W. L. Chan; Sheng Su; Yuanyuan Wang

2008-01-01

232

Creating Small Fault Dictionar-ies  

Microsoft Academic Search

Diagnostic fault simulation can generate enormous amounts of data. The techniques used to manage this data can have signi cant e ect on the outcome of the fault diagnosis procedure. We rst demonstrate that if information is removed from a fault dictionary, its ability to diagnose unmodeled faults may be severely curtailed even if dictionary quality metrics remain una ected;

B. Chess; T. Larrabee

1999-01-01

233

Inductive Fault Analysis of MOS Integrated Circuits  

Microsoft Academic Search

Inductive Fault Analysis (IFA) is a systematic Procedure to predict all the faults that are likely to occur in MOS integrated circuit or subcircuit The three major steps of the IFA procedure are: (1) generation of Physical defects using statistical data from the fabrication process; (2) extraction of circuit-level faults caused by these defects; and (3) classification of faults types

John Shen; W. Maly; F. J. Ferguson

1985-01-01

234

Composite fault location for Distribution Management Systems  

Microsoft Academic Search

The problem of fault location is an integral part of Distribution Management System (DMS) solutions. This paper presents a method of locating fault in unsymmetrical networks, including both radial and meshed parts of the network. The real-time information regarding the topological condition of the network and the status updates of the Fault Indicators are used as input to the fault

I. Dzafic; P. Mohapatra; H. T. Neisius

2010-01-01

235

Feedback bridging fault detection using current monitoring  

Microsoft Academic Search

Feedback bridging faults in CMOS circuits are difficult to detect by monitoring logic values. The authors study the possibility of detecting feedback bridging faults by using current monitoring. It is shown that by monitoring current, the feedback bridging faults that cause a metastable state can be detected. Using the same method, the feedback bridging faults can also be detected that

D. Lu; C. Q. Tong

1992-01-01

236

Sensitivity analysis of modular dynamic fault trees  

Microsoft Academic Search

Dynamic fault tree analysis, as currently supported by the Galileo software package, provides an effective means for assessing the reliability of embedded computer-based systems. Dynamic fault trees extend traditional fault trees by defining special gates to capture sequential and functional dependency characteristics. A modular approach to the solution of dynamic fault trees effectively applies Binary Decision Diagram (BOD) and Markov

Yong Ou; Joanne Bechta Dugan

2000-01-01

237

Variance analysis in software fault prediction models  

Microsoft Academic Search

Software fault prediction models play an important role in software quality assurance. They identify software subsystems (modules,components, classes, or files) which are likely to contain faults. These subsystems, in turn, receive additional resources for verification and validation activities. Fault prediction models are binary classifiers typically developed using one of the supervised learning techniques from either a subset of the fault

B Cukic; T Menzies; Y Jiang

2009-01-01

238

Spontaneous Rupture Processes on a Bending Fault  

Microsoft Academic Search

We simulated spontaneous rupture processes on vertical bending faults, using a 3-D finite-difference method. Since shear and normal stresses on the fault depend upon its angle to the principal stresses, rupture velocity and slip ahead of a bending point vary with strike change. Moreover, slip on a bending fault is less than one on a flat fault, since a bending

Y. Kase; S. M. Day

2004-01-01

239

Faults and folds, fact and fiction  

Microsoft Academic Search

After reviewing the microscopic and macroscopic texture of fault zones, the localisation of rupture and creep is described, and the reduced strength of fault zones is investigated. Simple strength and viscosity models for the whole lithosphere play a major role for the geometry of fault zones. Compressional faults (thrusts) show ramp- and flat structures, often soling in a (weak) detachment

R. Meissner

1996-01-01

240

Toward A Quantifiable Definition of Software Faults  

Microsoft Academic Search

An important aspect of developing models relating the number and type of faults in a software system to a set of structural measurement is defining what constitutes a fault. By definition, a fault is a structural imperfection in a software system that may lead to the system's eventually failing. A measurable and precise definition of what faults are makes it

John C. Munson; Allen P. Nikora

2002-01-01

241

Implications for mechanical properties of brittle faults from observations of the Punchbowl fault zone, California  

Microsoft Academic Search

Field observations of the Punchbowl fault zone, an inactive trace of the San Andreas, are integrated with results from experimental deformation of naturally deformed Punchbowl fault rocks for a qualitative description of the mechanical properties of the fault and additional information for conceptual models of crustal faulting. The Punchbowl fault zone consists of a single, continuous gouge layer bounded by

F. M. Chester; J. M. Logan

1986-01-01

242

A Fault Prediction Approach for Process Plants using Fault Tree Analysis in Sensor Malfunction  

Microsoft Academic Search

In this paper, a fault prediction approach for process plants using fault tree analysis is presented in the presence of no or false information of certain sensor. The fault propagation model is constructed by causal relationships from fault tree analysis (FTA). Knowledge about system failure, which is obtained from the fault propagation model, is represented as abnormality patterns in process

Zongxiao Yang; Xiaobo Yuan; Zhiqiang Feng; Kazuhiko Suzuki; Akira Inoue

2006-01-01

243

Study on equivalent calculation model of voltage across faulted open port in power system fault analysis  

Microsoft Academic Search

The paper proposes a method to calculate voltage across faulted open port of short circuit fault and open conductor fault in detail. Based on the superposition theory, the formula is deduced to calculate voltage across faulted open port of short circuit fault when the potential values and the phrase angles of generators in power system unequal to each other. On

Li Linlin; Zhao Shiqi; Xing Shuntao; Yuan Wei

2010-01-01

244

Predicting Fault-Prone Modules: A Comparative Study  

Microsoft Academic Search

Offshore and outsourced software development is a rapidly increasing trend in global software business environment. Predicting\\u000a fault-prone modules in outsourced software product may allow both parties to establish mutually satisfactory, cost-effective\\u000a testing strategies and product acceptance criteria, especially in iterative transitions. In this paper, based on industrial\\u000a software releases data, we conduct an empirical study to compare ten classifiers over

Hao Jia; Fengdi Shu; Ye Yang; Qing Wang

2009-01-01

245

Dates, rates and angles of faulting in the Peru-Chile Trench  

Microsoft Academic Search

THE high convergence rate between the Nazca Plate and the South American continent1 (10 cm yr-1) has been reported to result in rapid rates of vertical tectonism in the trench off northern Peru2,3. This paper presents additional evidence for recent, reverse faulting along the Peru-Chile Trench and new evidence for an older episode of normal faulting. We discuss the implications

Roger A. Prince

1978-01-01

246

Differential Fault Analysis on CLEFIA  

NASA Astrophysics Data System (ADS)

CLEFIA is a new 128-bit block cipher proposed by SONY corporation recently. The fundamental structure of CLEFIA is a generalized Feistel structure consisting of 4 data lines. In this paper, the strength of CLEFIA against the differential fault attack is explored. Our attack adopts the byte-oriented model of random faults. Through inducing randomly one byte fault in one round, four bytes of faults can be simultaneously obtained in the next round, which can efficiently reduce the total induce times in the attack. After attacking the last several rounds' encryptions, the original secret key can be recovered based on some analysis of the key schedule. The data complexity analysis and experiments show that only about 18 faulty ciphertexts are needed to recover the entire 128-bit secret key and about 54 faulty ciphertexts for 192/256-bit keys.

Chen, Hua; Wu, Wenling; Feng, Dengguo

247

Cell boundary fault detection system  

DOEpatents

A method determines a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

Archer, Charles Jens (Rochester, MN) [Rochester, MN; Pinnow, Kurt Walter (Rochester, MN) [Rochester, MN; Ratterman, Joseph D. (Rochester, MN) [Rochester, MN; Smith, Brian Edward (Rochester, MN) [Rochester, MN

2009-05-05

248

Fault Diagnosis in FET Modules.  

National Technical Information Service (NTIS)

The use of Field Effect Transistor (FET) devices in logic design has changed the design emphasis from networks composed of single logic gates to networks composed of complex functional modules. Fault diagnosis techniques which have been discussed in the l...

G. Metze M. Paige

1971-01-01

249

The intermediate principal stress effect on faulting and fault orientation  

NASA Astrophysics Data System (ADS)

We conducted true triaxial compression tests on rectangular prismatic specimens (19×19×38 mm) of siltstone core extracted from a depth of 1252 m, some 140 m below the borehole intersection with the Chelungpu Fault, Taiwan. Experiments consisted of four series of tests in each of which ?3 was kept constant and ?2 was varied from test to test. The major principal stress (?1), aligned with the long vertical side of the specimen, was raised at constant strain rate until a through-going, steeply dipping fault was initiated. As in igneous and metamorphic rocks previously tested, ?1 required to bring about faulting rose as ?2 was set at increasing levels above ?3. This observation reflects the significant contribution of ?2 to the compressive strength, and raises doubt about the suitability of the Mohr-Coulomb criterion. Rather, a strength criterion in terms of the invariants octahedral shear stress (?oct) as a function of mean stress (?oct) provides a good fit to the experimental data. In all tests fault strike was aligned with ?2 direction. The angle (or dip) ? of the fault was also strongly affected by ?2. For constant ?3 the angle rose with ?2, again departing from the Mohr-Coulomb criterion, which predicts a fault angle independent of the intermediate principal stress. The experimental results, revealing the dependence of fault angle ? on ?2, were compared with predictions based on shear localization theory incorporating a yield surface and plastic potential that depend on the following three stress invariants (rather than two, as in Rudnicki and Rice, 1975): ?oct, ?oct, and the Lode angle ?L (=arctan{[2?2 - ?1 - ?3]-[?3 (?1 - ?3)]}). Dependences of the yield surface and plastic potential on mean stress were inferred from the fault angles observed in axisymmetric compression and deviatoric pure shear. Using these relationships to predict fault angle ? for deviatoric stress states other than axisymmetric compression and pure shear, yields good agreement with the experimental observations. The results predict that for constant mean stress, the fault angle ? decreases as the deviatoric stress state varies from axisymmetric extension to axisymmetric compression. For fixed deviatoric stress states, ? decreases monotonically with increasing mean stress.

Haimson, Bezalel; Rudnicki, John

2010-05-01

250

Fault Diagnosis for Timed Automata  

Microsoft Academic Search

In this paper we study the problem of fault diagnosis in the context of dense-time automata. Our work is inspired from (SSL+95, SSL+96), who have studied the problem in the context of discrete event systems (DES) (RW87). We stick to the terminology used in the above papers, although we find the term fault detection, rather than diagnosis, more appropriate. Indeed,

Stavros Tripakis

2002-01-01

251

Types of Faults in California  

NSDL National Science Digital Library

This educational movie made using SCEC-VDO shows the differences between strike-slip faults and thrust faults in southern California.The Southern California Earthquake Center's Virtual Display of Objects SCEC-VDO is 3D visualization software that allows users to display study and make movies of earthquakes as they occur globally. SCEC-VDO was developed by interns of SCEC Undergraduate Studies in Earthquake Information Technology UseIT under the supervision of Sue Perry and Tom Jordan.

Jordan., Interns O.

252

Fault Tree Analysis: A Bibliography  

NASA Technical Reports Server (NTRS)

Fault tree analysis is a top-down approach to the identification of process hazards. It is as one of the best methods for systematically identifying an graphically displaying the many ways some things can go wrong. This bibliography references 266 documents in the NASA STI Database that contain the major concepts. fault tree analysis, risk an probability theory, in the basic index or major subject terms. An abstract is included with most citations, followed by the applicable subject terms.

2000-01-01

253

Software-controlled fault tolerance  

Microsoft Academic Search

adapt to the changing reliability and performance demands of a system. This paper proposes software-controlled fault tolerance, a concept allowing designers and users to tailor their perfor- mance and reliability for each situation. Several software-controllable fault detection techniques are then presented: SWIFT, a software-only technique, and CRAFT, a suite of hybrid hardware\\/ software techniques. Finally, the paper introduces PROFiT, a

George A. Reis; Jonathan Chang; Neil Vachharajani; Ram Rangan; David I. August; Shubhendu S. Mukherjee

2005-01-01

254

Nonlinear Network Dynamics on Earthquake Fault Systems  

SciTech Connect

Earthquake faults occur in interacting networks having emergent space-time modes of behavior not displayed by isolated faults. Using simulations of the major faults in southern California, we find that the physics depends on the elastic interactions among the faults defined by network topology, as well as on the nonlinear physics of stress dissipation arising from friction on the faults. Our results have broad applications to other leaky threshold systems such as integrate-and-fire neural networks.

Rundle, Paul B.; Rundle, John B.; Tiampo, Kristy F.; Sa Martins, Jorge S.; McGinnis, Seth; Klein, W.

2001-10-01

255

Tutorial: Advanced fault tree applications using HARP  

NASA Technical Reports Server (NTRS)

Reliability analysis of fault tolerant computer systems for critical applications is complicated by several factors. These modeling difficulties are discussed and dynamic fault tree modeling techniques for handling them are described and demonstrated. Several advanced fault tolerant computer systems are described, and fault tree models for their analysis are presented. HARP (Hybrid Automated Reliability Predictor) is a software package developed at Duke University and NASA Langley Research Center that is capable of solving the fault tree models presented.

Dugan, Joanne Bechta; Bavuso, Salvatore J.; Boyd, Mark A.

1993-01-01

256

Earthquake Dynamics at Linked Fault Stepovers  

Microsoft Academic Search

Previous studies of strike-slip fault systems with linking dip-slip faults (Oglesby, 2003) have indicated that with equivalent shear and normal stresses on all segments, extensional stepovers with linking normal faults are more likely to produce multi-segment events that rupture the entire fault system, compared to compressive stepovers with linking thrust faults. This difference is due to the sign of the

D. D. Oglesby

2004-01-01

257

Passive fault current limiting device  

DOEpatents

A passive current limiting device and isolator is particularly adapted for use at high power levels for limiting excessive currents in a circuit in a fault condition such as an electrical short. The current limiting device comprises a magnetic core wound with two magnetically opposed, parallel connected coils of copper, a high temperature superconductor or other electrically conducting material, and a fault element connected in series with one of the coils. Under normal operating conditions, the magnetic flux density produced by the two coils cancel each other. Under a fault condition, the fault element is triggered to cause an imbalance in the magnetic flux density between the two coils which results in an increase in the impedance in the coils. While the fault element may be a separate current limiter, switch, fuse, bimetal strip or the like, it preferably is a superconductor current limiter conducting one-half of the current load compared to the same limiter wired to carry the total current of the circuit. The major voltage during a fault condition is in the coils wound on the common core in a preferred embodiment. 6 figs.

Evans, D.J.; Cha, Y.S.

1999-04-06

258

Software Fault Tolerance: A Tutorial  

NASA Technical Reports Server (NTRS)

Because of our present inability to produce error-free software, software fault tolerance is and will continue to be an important consideration in software systems. The root cause of software design errors is the complexity of the systems. Compounding the problems in building correct software is the difficulty in assessing the correctness of software for highly complex systems. After a brief overview of the software development processes, we note how hard-to-detect design faults are likely to be introduced during development and how software faults tend to be state-dependent and activated by particular input sequences. Although component reliability is an important quality measure for system level analysis, software reliability is hard to characterize and the use of post-verification reliability estimates remains a controversial issue. For some applications software safety is more important than reliability, and fault tolerance techniques used in those applications are aimed at preventing catastrophes. Single version software fault tolerance techniques discussed include system structuring and closure, atomic actions, inline fault detection, exception handling, and others. Multiversion techniques are based on the assumption that software built differently should fail differently and thus, if one of the redundant versions fails, it is expected that at least one of the other versions will provide an acceptable output. Recovery blocks, N-version programming, and other multiversion techniques are reviewed.

Torres-Pomales, Wilfredo

2000-01-01

259

Mechanical strengths of fault and its surrounding rocks on an active creeping fault at Chihshang, Eastern Taiwan: an approach of numerical modeling  

NASA Astrophysics Data System (ADS)

The Chihshang fault is one of the most active segments of the Longitudinal Valley Fault, the plate suture between the converging Philippine and Eurasian plates in eastern Taiwan. Two moderate earthquakes of M 6.2 and M 6.5 resulted from rupturing of the Chihshang fault with substantial surface ruptures, occurred in 1951 and 2003, respectively. In between the 50-year inter-seismic period, the Chihshang fault reveals a seasonal creeping behavior at a rapid rate of about 20-30 mm/yr, at least during the last 25 years with instrumental observation. Based on data from the Chinyuan geodetic network measured once or twice per year across the 150-m-wide fault zone since 1998, we deployed elastic and visco-elastic modeling in order to seek the fault geometry and the mechanical behaviors of the fault and its surround rocks, in the uppermost 120 m surface level. By searching best-fits for the least residual mean values, we obtained an optimal model with the following parameters: 1) 15-20 m of unconsolidated covered deposits for the surfacial locked zone, 2) 40°-50° of the fault dip angle, 3) cohesion of about 15 KPa and friction angle of 9°-12° for the mechanical strength of the fault, 4) Young's modulus of about 0.1-0.3 GPa for the surrounding rocks. These results show that the Chihshang fault at the Chinyuan site has a relatively week mechanical strength, which is consistent with the fact of continuously surface creep. However, creep occurred only in wet seasons indicates the mechanical strength of the fault might become significantly stronger during the dry season when no surface slip occurred. The optimal model also indicates that a gentle anticlinal fold developed in the hanging wall of the fault and that the slip on the fault plane decreases gradually from depth toward the surface with near-zero slip in the upper 15-20 m. It is worth to note that the surface ruptures on cultural feature, such as brittle concrete retaining walls, distributed in a rather wide fault zone, as interpreted as being due to a growing fold structure with a wide wavelength. It should be taken into consideration for mitigation against seismic hazards.

Lee, J.; Chang, K.; Huang, J.; Lin, M.

2005-12-01

260

Coseismic paleomagnetic signal in fault pseudotachylytes?  

NASA Astrophysics Data System (ADS)

The 59 Ma-old fault-related pseudotachylytes of the Peninsular Ranges of California have been investigated from the microstructural and magnetic point of view. These veins have a 30-fold increase in magnetic susceptibility compared to their tonalitic host-rock. The increase results from the breakdown of mafic silicates during frictional melting and subsequent formation of abundant fine grained magnetite grains. Upon rapid cooling of the pseudotachylyte melt in the Earth's magnetic field the rocks acquire a strong thermoremanent magnetization. In addition to this dominant process some samples exhibit a "lightning-induced" remanent magnetization acquired during seismic slip in the presence of a high magnetic field. This unusual remanence component is anomalous in direction and tends to be at high angle to the pseudotachylyte vein plane. We propose that the coseismic lightning-induced magnetization is caused by electrical currents possibly similar to those responsible for earthquake lightnings.

Ferre, E.; Geissman, J. W.; Zechmeister, M. S.

2012-04-01

261

Suppression of strike-slip fault zones by preexisting crustal heterogeneities  

NASA Astrophysics Data System (ADS)

Although transform (strike-slip on land) faults are a defining feature of plate tectonics, plate boundary models show several regions where shearing is the primary regional deformation mechanism that completely lack or have underdeveloped strike-slip fault systems with respect to their slip rate. Regions that exhibit rapid toroidal (shearing) flow as indicated by GPS velocities, focal mechanisms, and/or neotectonic models but lack pervasive strike-slip faulting tend to possess common features that predate shearing, such as: (1) extensive fracturing perpendicular or sub-perpendicular to the shear plane (e.g., South Iceland Seismic Zone and Walker Lane, CA), and/or (2) regional cover of flood basalts or andesites containing columnar joints (e.g., Brothers Fault Zone, Oregon). We present a new plane-stress finite-strain analog model created to investigate the evolution of primary deformation zones in pure strike-slip fault systems where crustal heterogeneities emulating (1) and (2) exist prior to shear initiation. Experimental results indicate that, in comparison to systems with originally pristine surfaces, strike-slip fault systems containing preexisting structures develop more distributed geometries and that more than twice as much net offset is required for throughgoing strike-slip faulting to occur. These results provide new insight for kinematic interpretations of structural data from fault systems on Earth, Venus and other terrestrial bodies where crustal heterogeneities such as shear-plane perpendicular fractures and/or basaltic or andesitic flood basalts are present prior to shear initiation. Direct and independent confirmation of fault zone suppression could be provided through detailed geologic analyses of underdeveloped fault zones on Earth that exemplify the fault zone development observed in these experiments (e.g., Walker Lane, CA-NV).

Curren, I. S.; Bird, P.

2013-12-01

262

Quantifying the Growth History of an Ancient Border Fault System, and the Role of Normal Fault Growth on Sedimentation During Basin Formation: a Case Study from the Late Cambrian Owen Conglomerate, West Coast Range, western Tasmania, Australia  

NASA Astrophysics Data System (ADS)

The stratigraphic and depositional architecture of evolving extensional basins is principally controlled by normal fault growth through the generation of accommodation space. The history of border fault systems therefore controls the evolution of internal drainage patterns and basin facies distributions. Despite recent advances in the understanding of present-day normal fault growth, quantifying the effect of normal fault evolution on the architecture of ancient sedimentary basins has been largely obscured by post-rift deformation and erosion. The Late Cambrian Owen Conglomerate along the West Coast Range of western Tasmania, Australia, includes thick fluvial sandstone and marine turbidite sequences, as well as fluvial and marine conglomerates. The accumulation of this formation provides excellent insights into the rift-fill history of an ancient extensional basin, due to rugged, glaciated topography and exceptional outcrops, and the typically overfilled nature of the basin, which preserves the fault displacement history. Structural traverses have delineated the geometry of the extensional fault system active during deposition of the Owen Conglomerate. The fault system comprises a segmented array of border faults with variable along-strike polarity. Minimum displacements were calculated from present-day stratigraphic thicknesses, and define a roughly symmetric displacement-length profile that resembles that of a single, isolated fault, with maximum displacement (Dmax) located at the centre of the fault array, and decreasing displacement toward the distal segments. Displacement along the fault system, however, indicates a varied growth history through time. Isolated faulting (Stage 1) occurred during the early stages of rifting, when small fault segments grew in isolation. Stage 1 faults exhibit a Dmax at the centre of each individual segment. Rapid propagation of fault segments to maximum strike length occurred early in the basin history, with only limited interaction and feedback between individual segments. Continued growth faulting (Stage 2) resulted in migration of the locus of maximum displacement as individual segments began to interact and link. Eventual linkage of fault segments (Stage 3) occurred during the final stages of rifting, where the overall system exhibits a characteristic, through-going, displacement-length profile. Integration of lithofacies distributions, isopach maps and palaeocurrent data with the structural dataset shows that the stratigraphic architecture is strongly coupled with the development of the border fault system, and offers a high resolution model for fault development. While the generation of accommodation space adjacent to footwall scarps facilitated the development of a hanging-wall, dip-slope fluvial catchment and axial-through drainage networks, tectonic subsidence also provided a crucial trigger for the onset of isolated marine sedimentation where accommodation space generated by the localised accumulation of displacement on individual segments outpaced sediment supply.

Noll, C. A.; Hall, M.

2003-12-01

263

Anisotropy of permeability in faulted porous sandstones  

NASA Astrophysics Data System (ADS)

Studies of fault rock permeabilities advance the understanding of fluid migration patterns around faults and contribute to predictions of fault stability. In this study a new model is proposed combining brittle deformation structures formed during faulting, with fluid flow through pores. It assesses the impact of faulting on the permeability anisotropy of porous sandstone, hypothesising that the formation of fault related micro-scale deformation structures will alter the host rock porosity organisation and create new permeability pathways. Core plugs and thin sections were sampled around a normal fault and oriented with respect to the fault plane. Anisotropy of permeability was determined in three orientations to the fault plane at ambient and confining pressures. Results show that permeabilities measured parallel to fault dip were up to 10 times higher than along fault strike permeability. Analysis of corresponding thin sections shows elongate pores oriented at a low angle to the maximum principal palaeo-stress (?1) and parallel to fault dip, indicating that permeability anisotropy is produced by grain scale deformation mechanisms associated with faulting. Using a soil mechanics 'void cell model' this study shows how elongate pores could be produced in faulted porous sandstone by compaction and reorganisation of grains through shearing and cataclasis.

Farrell, N. J. C.; Healy, D.; Taylor, C. W.

2014-06-01

264

Software reliability through fault-avoidance and fault-tolerance  

NASA Technical Reports Server (NTRS)

Twenty independently developed but functionally equivalent software versions were used to investigate and compare empirically some properties of N-version programming, Recovery Block, and Consensus Recovery Block, using the majority and consensus voting algorithms. This was also compared with another hybrid fault-tolerant scheme called Acceptance Voting, using dynamic versions of consensus and majority voting. Consensus voting provides adaptation of the voting strategy to varying component reliability, failure correlation, and output space characteristics. Since failure correlation among versions effectively reduces the cardinality of the space in which the voter make decisions, consensus voting is usually preferable to simple majority voting in any fault-tolerant system. When versions have considerably different reliabilities, the version with the best reliability will perform better than any of the fault-tolerant techniques.

Vouk, Mladen A.; Mcallister, David F.

1991-01-01

265

Quantifying Morphologic Changes in a Low Gradient River Crossing Southeast Louisiana Fault Zones  

NASA Astrophysics Data System (ADS)

This study investigates the signature of faulting in low gradient, alluvial rivers crossing the Baton Rouge fault zone (BRFZ) and Denham Springs-Scotlandville fault zone (DSSFZ), which encompass a set of East-West striking normal faults in southeast Louisiana. These faults exhibit surface expressions associated with up to a few meters of vertical displacement of Late Pleistocene sediments, but little is known about their activity during the Holocene. Our study aims to quantify geomorphic changes in a number of rivers that cross these fault zones and to use these changes to gain insight into the history of faulting in the region. We hypothesize that fault movement will be evident in patterns of river sinuosity, slope, and width to depth ratio. We focus on four subparallel channels of various discharges that cross either or both the BRFZ and the DSSFZ. Information on local fault scarp heights and channel reaches are extracted by GIS analysis of the LA LiDAR 5 m DEM, as well as flow modeling using the HEC-RAS software program. On the Tickfaw River, we conducted field surveys using differential GPS to record contemporary water surface slopes and channel location. Historic channel features on the Tickfaw are characterized using a series of aerial photographs dating back to 1952. Over the past 50 years, the Tickfaw River has shortened its course through the study area significantly (~4.9%) by means of meander cutoffs. Since 1952, sinuosity (P) has decreased in all of the Tickfaw channel reaches that cross fault segments. Currently, the sinuosity is extremely low (average P = 1.14) where the river crosses the DSSFZ and slightly higher where the river crosses the BRFZ (average P = 1.9). We use the LiDAR data to quantify offset on the faults that the river crosses. These values will be compared with the average lateral migration rate of the river in order to better understand the time scales over which both processes operate. If the faults appear to have little morphologic impact on the river, it is likely that that fluvial migration rates are rapid enough to erase any signature of the accumulated throw from the faults. With continued analysis, our goal is to develop a reliable method for using alluvial rivers to help unravel the history of fault systems in low gradient landscapes, with possible applications for detecting regions vulnerable to fault-related subsidence.

Fischer, G.; Gasparini, N. M.; Dawers, N. H.

2011-12-01

266

Graphite as a fault lubricant  

NASA Astrophysics Data System (ADS)

Graphite is a well-known solid lubricant, and has been found in ~14 vol% of fraction from fault zones in a variety of geological settings (e.g. the Atotsugawa fault system, Japan: Oohashi et al., 2011a, submitted; the KTB borehole, Germany: Zulauf et al., 1990; and the Err nappe detachment fault, Switzerland: Manatschal, 1999). However, it received little attention even though friction of graphite gouge shows strikingly low (steady-state friction coefficient ?0.1) over seven orders of magnitude in slip rate (0.16 ?m/s to 1.3 m/s; Oohashi et al., 2011b). Thus the friction experiments were performed on mixed graphite and quartz gouges with different compositions in order to determine the minimum amount of graphite in reducing the frictional strength of faults dramatically, by using a rotary-shear low to high-velocity friction apparatus. Experimental result clearly indicates that the friction coefficient of the mixture gouge decreases with graphite content following a power-law relation irrespective of slip rate; it starts to reduce at the fraction of 5 vol% and reaches to the almost same level of pure graphite gouge at the fraction of more than 20 vol%. This result implies that the 14 vol% of graphite in natural fault rock is enough amount for reduce the shear strength to half of initial. According to the textural observation, slight weakening of 5-8 vol% of graphite mixture is associated with the development of partial connection of graphite matrix, forming a slip localized surface. On the other hand, the formation of through-going connection of diffused graphite-matrix zones along shear planes is most likely to have caused the dramatic weakening of gouge with graphite of more than 20 vol%. The non-linear power-law dependency of friction on graphite content leads to more efficient reduction of fault strength as compared with the previously reported almost linear dependency on the effects of clay minerals (e.g. Shimamoto & Logan, 1981). Hence the result demonstrates the potential importance of graphite as a weakening agent of mature faults as graphite can reduce friction efficiently as compared with other weak clay minerals. Such mechanical properties of graphite may explain the lack of pronounced heat flow in major crustal faults and the long-term fault weakening.

Oohashi, K.; Hirose, T.; Shimamoto, T.

2011-12-01

267

Matching pursuit of an adaptive impulse dictionary for bearing fault diagnosis  

NASA Astrophysics Data System (ADS)

The sparse decomposition based on matching pursuit is an adaptive sparse expression of the signals. An adaptive matching pursuit algorithm that uses an impulse dictionary is introduced in this article for rolling bearing vibration signal processing and fault diagnosis. First, a new dictionary model is established according to the characteristics and mechanism of rolling bearing faults. The new model incorporates the rotational speed of the bearing, the dimensions of the bearing and the bearing fault status, among other parameters. The model can simulate the impulse experienced by the bearing at different bearing fault levels. A simulation experiment suggests that a new impulse dictionary used in a matching pursuit algorithm combined with a genetic algorithm has a more accurate effect on bearing fault diagnosis than using a traditional impulse dictionary. However, those two methods have some weak points, namely, poor stability, rapidity and controllability. Each key parameter in the dictionary model and its influence on the analysis results are systematically studied, and the impulse location is determined as the primary model parameter. The adaptive impulse dictionary is established by changing characteristic parameters progressively. The dictionary built by this method has a lower redundancy and a higher relevance between each dictionary atom and the analyzed vibration signal. The matching pursuit algorithm of an adaptive impulse dictionary is adopted to analyze the simulated signals. The results indicate that the characteristic fault components could be accurately extracted from the noisy simulation fault signals by this algorithm, and the result exhibited a higher efficiency in addition to an improved stability, rapidity and controllability when compared with a matching pursuit approach that was based on a genetic algorithm. We experimentally analyze the early-stage fault signals and composite fault signals of the bearing. The results further demonstrate the effectiveness and superiority of the matching pursuit algorithm that uses the adaptive impulse dictionary. Finally, this algorithm is applied to the analysis of engineering data, and good results are achieved.

Cui, Lingli; Wang, Jing; Lee, Seungchul

2014-05-01

268

Constraining Fault Evolution at an Active Extensional Relay: Star Valley, Wyoming  

NASA Astrophysics Data System (ADS)

Relay zones, the sites where faults overlap and become linked, provide important insights into the processes by which fault segments coalesce. Whilst numerous studies have been made of the detailed structural geometry of relay zones, our understanding of the temporal evolution of faulting during relay formation remains limited. We focus on the Grover relay, a 4-km-wide en echelon step in the Star Valley fault located at the eastern margin of the Basin and Range province, Wyoming. Several coeval latest Quaternary ruptures have been documented on both segments by paleoseismological studies suggesting that the north and south segments are well linked. We use sedimentological and geomorphic observations to investigate faulting-landscape interactions and to propose a model of relay evolution. Typically relay zones comprise an en echelon fault overlap of inboard and outboard faults. At the Grover relay, the outboard fault loses displacement northward into a N-plunging fault-related anticline that has deformed early synrift deposits. Early syn-rift and pre-rift rocks are also preserved between the segments of the Star Valley faults and are being exhumed in the footwall of the outboard fault suggesting that the relay is not a newly developing one. Stratigraphic relations at the initial point of fault overlap indicate that approximately 2-my-old syn-rift alluvial fan conglomerates derived from erosion of the inboard footwall onlap and are ponded against the hangingwall dipslope of the outboard segment. This indicates that the Star Valley segments were in overlap position and the outboard fault formed topography during conglomerate deposition. This pinning point provides a minimum age for onset of fault overlap and permits estimation of a propagation rate for the outboard fault tip of approximately 9 mm/yr. This is an order of magnitude greater than Holocene fault displacement rates derived from trenching studies. Analysis of drainage patterns indicates that streams on the outboard footwall have incised headward in response to displacement on the outboard fault and captured drainage that originally flowed down the relay. Captured streams show well-developed concave profiles. Streams on the outboard fault tip by contrast show convex-up profiles indicating that tectonics dominates the streams ability to incise and develop an equilibrium profile. Stream capture has resulted in major denudation of the outboard footwall suggesting that this may be an important process in local footwall erosion. Comparison with numerical landscape evolution models (Densmore et al. 2003) suggests that capture of early formed relay zone drainage occurs in situations where fault segments propagate into overlap position and link rapidly, after which displacement addition on the overlapped segments drives the rapid baselevel fall that leads to capture. We hypothesise that the relative timeframe of fault linkage plays a critical role in landscape evolution and sediment dispersal patterns at evolving relays.

Gupta, S.; Davis, A. M.; Densmore, A. L.; Dawers, N. H.

2003-12-01

269

Late Quaternary Deformation Along the Wairarapa Fault, North Island, New Zealand  

NASA Astrophysics Data System (ADS)

The Wairarapa fault, one of the largest active faults in the hanging wall of the Hikurangi subduction margin, New Zealand, averaged 16m dextral slip during the M >8.1 1855 earthquake. Previous workers inferred that uplift of 2.7m at the coast, observed by a surveyor in 1855, occurred on the southern continuation of the Wairarapa fault, the Wharekauhau (WH) thrust. New mapping, stratigraphic, and paloseismologic results from the WH thrust suggest the pattern of surface rupture in 1855 and earlier earthquakes was significantly different than previously inferred, requiring a more complex model for seismic hazard and tectonic evolution of the region. Detailed mapping indicates that the coastal segment of the WH thrust did not rupture the surface in 1855. The thrust, a major range-bounding fault, emplaces Mesozoic graywacke over ~80-100 ka last- interglacial marine, and lacustrine rocks, and in part coeval to younger alluvial gravels. Fault activity is indicated by facies and thickness changes. This older sequence is tilted and overlapped unconformably by a silt layer and much less deformed alluvial fan gravels that range in age from >22ka to <9 ka. These younger gravels were deposited in a valley incised across the fault scarp, in-filled this topography, and show no evidence of syn-depositional deformation. New 14C ages record a period of fault inactivity from 14 - 9 ka (calib yrs BP). The abandoned, overlapping fan surface is slightly deformed across the fault (15 m of folding- related throw). We infer that the thrust has propagated eastward in the subsurface, uplifting the abandoned WH fault, an inference that is supported by the pattern of Holocene incision. The only recent faulting consists of subvertical en echelon segments that have undergone minor dip-slip and dextral slip. A trench excavated across the fault scarp in late Holocene gravels suggests that the only fault along the trace of the WH thrust that broke within 3 m of the surface in 1855 was a minor strike-slip fault splay. New14C ages are consistent with the most recent event occurring in 1855 and suggest one earlier event. The range-bounding trace of the WH thrust appears to have been abandoned in the Holocene, with deformation occuring both west and east of this fault. Thus southern end of the Wairarapa fault consists of at least three active structures: 1) A western oblique-slip fault (or fault zone) that has ruptured repeatedly in the Holocene, including 1855, uplifting the Rimutaka anticline and accommodating large-magnitude strike-slip. Details of the 1855 event are obscured by landsliding in the Rimutaka range but the uplift is recorded by a flight of beach ridges at Turakirae Head; 2) a middle strike-slip strand that in part coincides with the projected trace of the abandoned WH thrust: 3) an eastern blind thrust that initiated after 9 ka and that has an unknown rupture history. Uplift with respect to sea level on the middle and eastern strands of the WH fault zone totals ~1mm/yr over the last 125 ka, and is indistinguishable in rate from that measured along the main (strike- slip) part of the Wairarapa fault to the north. To the west of the WH fault, the crest of the Rimutaka anticline at the coast is uplifting at 3 times this rate, (McSaveny et al., in press). The relationship between this locally enhanced rate of coastal uplift at the southern end of the Wairarapa fault zone, and the WH fault is apparently complex and changing rapidly in time, but has important implications for understanding seismic hazard and tectonics of this part of the Hikurangi margin.

Schermer, E. R.; Little, T. A.

2006-12-01

270

Transient Faults in Computer Systems  

NASA Technical Reports Server (NTRS)

A powerful technique particularly appropriate for the detection of errors caused by transient faults in computer systems was developed. The technique can be implemented in either software or hardware; the research conducted thus far primarily considered software implementations. The error detection technique developed has the distinct advantage of having provably complete coverage of all errors caused by transient faults that affect the output produced by the execution of a program. In other words, the technique does not have to be tuned to a particular error model to enhance error coverage. Also, the correctness of the technique can be formally verified. The technique uses time and software redundancy. The foundation for an effective, low-overhead, software-based certification trail approach to real-time error detection resulting from transient fault phenomena was developed.

Masson, Gerald M.

1993-01-01

271

Faulting in porous carbonate grainstones  

NASA Astrophysics Data System (ADS)

In the recent past, a new faulting mechanism has been documented within porous carbonate grainstones. This mechanism is due to strain localization into narrow tabular bands characterized by both volumetric and shear strain; for this reason, these features are named compactive shear bands. In the field, compactive shear bands are easily recognizable because they are lightly coloured with respect to the parent rock, and/or show a positive relief because of their increased resistance to weathering. Both characteristics, light colours and positive relief, are a consequence of the compaction processes that characterize these bands, which are the simplest structure element that form within porous carbonate grainstones. With ongoing deformation, the single compactive shear bands, which solve only a few mm of displacement, may evolve into zone of compactive shear bands and, finally, into well-developed faults characterized by slip surfaces and fault rocks. Field analysis conducted in key areas of Italy allow us to documented different modalities of interaction and linkage among the compactive shear bands: (i) a simple divergence of two different compactive shear bands from an original one, (ii) extensional and contractional jogs formed by two continuous, interacting compactive shear bands, and (iii) eye structures formed by collinear interacting compactive shear bands, which have been already described for deformation bands in sandstones. The last two types of interaction may localize the formation of compaction bands, which are characterized by pronounced component of compaction and negligible components of shearing, and/or pressure solution seams. All the aforementioned types of interaction and linkage could happen at any deformation stage, single bands, zone of bands or well developed faults. The transition from one deformation process to another, which is likely to be controlled by the changes in the material properties, is recorded by different ratios and distributions of the fault dimensional attributes. The results of field analysis are consistent with length (L), displacement (D) and thickness (T) of single compactive shear bands clustering around given values, peculiar to the individual lithologies, and does not point out to any scale relationship among these parameters. On the contrary, in zones of shear bands and well-developed faults the D values are maximum in the central portion of individual elements. Differently from what characterize the well-developed faults, in which the slip increments are solved along the main slip surfaces, within zones of compactive shear bands the displacement varies according to the number of individual single bands, so that an increased displacement is related to an higher number of bands. As a consequence, the T-D plot concerning zones of compactive shear bands and well-developed faults show two different populations, which suggest that well-developed faults are much efficient to resolve displacement, with respect the zone of shear bands, because they include sharp slip surfaces. The petrographical and petrophysical properties of the tectonic features described above, which have been assessed by mean of detailed laboratory analyses, are consistent with the single compactive shear bands and zones of shear bands behaving as seals for underground fluid flow with respect to the host rock. These features, strongly present within the fault damage zones of well-developed faults, may compartmentalize the fluid flow in faulted carbonate reservoirs.

Tondi, Emanuele; Agosta, Fabrizio

2010-05-01

272

InSAR measurements around active faults: creeping Philippine Fault and un-creeping Alpine Fault  

NASA Astrophysics Data System (ADS)

Recently, interferometric synthetic aperture radar (InSAR) time-series analyses have been frequently applied to measure the time-series of small and quasi-steady displacements in wide areas. Large efforts in the methodological developments have been made to pursue higher temporal and spatial resolutions by using frequently acquired SAR images and detecting more pixels that exhibit phase stability. While such a high resolution is indispensable for tracking displacements of man-made and other small-scale structures, it is not necessarily needed and can be unnecessarily computer-intensive for measuring the crustal deformation associated with active faults and volcanic activities. I apply a simple and efficient method to measure the deformation around the Alpine Fault in the South Island of New Zealand, and the Philippine Fault in the Leyte Island. I use a small-baseline subset (SBAS) analysis approach (Berardino, et al., 2002). Generally, the more we average the pixel values, the more coherent the signals are. Considering that, for the deformation around active faults, the spatial resolution can be as coarse as a few hundred meters, we can severely 'multi-look' the interferograms. The two applied cases in this study benefited from this approach; I could obtain the mean velocity maps on practically the entire area without discarding decorrelated areas. The signals could have been only partially obtained by standard persistent scatterer or single-look small-baseline approaches that are much more computer-intensive. In order to further increase the signal detection capability, it is sometimes effective to introduce a processing algorithm adapted to the signal of interest. In an InSAR time-series processing, one usually needs to set the reference point because interferograms are all relative measurements. It is difficult, however, to fix the reference point when one aims to measure long-wavelength deformation signals that span the whole analysis area. This problem can be solved by adding the displacement offset in each interferogram as a model parameter and solving the system of equations with the minimum norm condition. This way, the unknown offsets can be automatically determined. By applying this method to the ALOS/PALSAR data acquired over the Alpine Fault, I obtained the mean velocity map showing the right-lateral relative motion of the blocks north and south of the fault and the strain concentration (large velocity gradient) around the fault. The velocity gradient around the fault has along-fault variation, probably reflecting the variation in the fault locking depth. When one aims to detect fault creeps, i.e., displacement discontinuity in space, one can additionally introduce additional parameters to describe the phase ramps in the interferograms and solve the system of equations again with the minimum norm condition. Then, the displacement discontinuity appears more clearly in the result at the cost of suppressing long-wavelength displacements. By applying this method to the ALOS/PALSAR data acquired over the Philippine Fault in Leyte Island, I obtained the mean velocity map showing fault creep at least in the northern and central parts of Leyte at a rate of around 10 mm/year.

Fukushima, Y.

2013-12-01

273

Faulting at Mormon Point, Death Valley, California: A low-angle normal fault cut by high-angle faults  

NASA Astrophysics Data System (ADS)

New geophysical and fault kinematic studies indicate that late Cenozoic basin development in the Mormon Point area of Death Valley, California, was accommodated by fault rotations. Three of six fault segments recognized at Mormon Point are now inactive and have been rotated to low dips during extension. The remaining three segments are now active and moderately to steeply dipping. From the geophysical data, one active segment appears to offset the low-angle faults in the subsurface of Death Valley.

Keener, Charles; Serpa, Laura; Pavlis, Terry L.

1993-04-01

274

A Dynamic Finite Element Method for Simulating the Physics of Faults Systems  

NASA Astrophysics Data System (ADS)

We introduce a dynamic Finite Element method using a novel high level scripting language to describe the physical equations, boundary conditions and time integration scheme. The library we use is the parallel Finley library: a finite element kernel library, designed for solving large-scale problems. It is incorporated as a differential equation solver into a more general library called escript, based on the scripting language Python. This library has been developed to facilitate the rapid development of 3D parallel codes, and is optimised for the Australian Computational Earth Systems Simulator Major National Research Facility (ACcESS MNRF) supercomputer, a 208 processor SGI Altix with a peak performance of 1.1 TFlops. Using the scripting approach we obtain a parallel FE code able to take advantage of the computational efficiency of the Altix 3700. We consider faults as material discontinuities (the displacement, velocity, and acceleration fields are discontinuous at the fault), with elastic behavior. The stress continuity at the fault is achieved naturally through the expression of the fault interactions in the weak formulation. The elasticity problem is solved explicitly in time, using the Saint Verlat scheme. Finally, we specify a suitable frictional constitutive relation and numerical scheme to simulate fault behaviour. Our model is based on previous work on modelling fault friction and multi-fault systems using lattice solid-like models. We adapt the 2D model for simulating the dynamics of parallel fault systems described to the Finite-Element method. The approach uses a frictional relation along faults that is slip and slip-rate dependent, and the numerical integration approach introduced by Mora and Place in the lattice solid model. In order to illustrate the new Finite Element model, single and multi-fault simulation examples are presented.

Saez, E.; Mora, P.; Gross, L.; Weatherley, D.

2004-12-01

275

Update: San Andreas Fault experiment  

NASA Technical Reports Server (NTRS)

Satellite laser ranging techniques are used to monitor the broad motion of the tectonic plates comprising the San Andreas Fault System. The San Andreas Fault Experiment, (SAFE), has progressed through the upgrades made to laser system hardware and an improvement in the modeling capabilities of the spaceborne laser targets. Of special note is the launch of the Laser Geodynamic Satellite, LAGEOS spacecraft, NASA's only completely dedicated laser satellite in 1976. The results of plate motion projected into this 896 km measured line over the past eleven years are summarized and intercompared.

Christodoulidis, D. C.; Smith, D. E.

1984-01-01

276

Latent Sector Faults and Reliability of Disk Arrays.  

National Technical Information Service (NTIS)

This thesis studies the effects of latent sensor faults on reliability, performance, and combined performability of disk arrays. This is done by developing two novel reliability models that include two fault types: disk unit faults and sector faults. The ...

H. H. Kari

1997-01-01

277

Promises and Fault-Tolerant Database Access.  

National Technical Information Service (NTIS)

This paper studies the power of access, especially fault-tolerant access, to probabilistic databases and to unambiguous databases . We study fault-tolerant access to probabilistic computation, and completely characterize the complexity classes R and ZPP i...

J. Cai L. A. Hemachandra J. Vyskoc

1993-01-01

278

Yield Enhancement by Fault Tolerant Systolic Arrays.  

National Technical Information Service (NTIS)

In this paper interstitial fault tolerance (IFT), a technique for incorporating fault tolerance into systolic arrays in a natural manner, is discussed. IFT can be used for reliable computation or for yield enhancement. Here the author compares IFT used fo...

R. H. Kuhn

1983-01-01

279

Solar Dynamic Power System Fault Diagnosis  

NASA Technical Reports Server (NTRS)

The objective of this research is to conduct various fault simulation studies for diagnosing the type and location of faults in the power distribution system. Different types of faults are simulated at different locations within the distribution system and the faulted waveforms are monitored at measurable nodes such as at the output of the DDCU's. These fault signatures are processed using feature extractors such as FFT and wavelet transforms. The extracted features are fed to a clustering based neural network for training and subsequent testing using previously unseen data. Different load models consisting of constant impedance and constant power are used for the loads. Open circuit faults and short circuit faults are studied. It is concluded from present studies that using features extracted from wavelet transforms give better success rates during ANN testing. The trained ANN's are capable of diagnosing fault types and approximate locations in the solar dynamic power distribution system.

Momoh, James A.; Dias, Lakshman G.

1996-01-01

280

An experimental study of memory fault latency  

NASA Technical Reports Server (NTRS)

The difficulty with the measurement of fault latency is due to the lack of observability of the fault occurrence and error generation instants in a production environment. The authors describe an experiment, using data from a VAX 11/780 under real workload, to study fault latency in the memory subsystem accurately. Fault latency distributions are generated for stuck-at-zero (s-a-0) and stuck-at-one (s-a-1) permanent fault models. The results show that the mean fault latency of an s-a-0 fault is nearly five times that of the s-a-1 fault. An analysis of variance is performed to quantify the relative influence of different workload measures on the evaluated latency.

Chillarege, Ram; Iyer, Ravi K.

1989-01-01

281

Detection of faults and software reliability analysis  

NASA Technical Reports Server (NTRS)

Specific topics briefly addressed include: the consistent comparison problem in N-version system; analytic models of comparison testing; fault tolerance through data diversity; and the relationship between failures caused by automatically seeded faults.

Knight, J. C.

1987-01-01

282

Parametric Modeling and Fault Tolerant Control  

NASA Technical Reports Server (NTRS)

Fault tolerant control is considered for a nonlinear aircraft model expressed as a linear parameter-varying system. By proper parameterization of foreseeable faults, the linear parameter-varying system can include fault effects as additional varying parameters. A recently developed technique in fault effect parameter estimation allows us to assume that estimates of the fault effect parameters are available on-line. Reconfigurability is calculated for this model with respect to the loss of control effectiveness to assess the potentiality of the model to tolerate such losses prior to control design. The control design is carried out by applying a polytopic method to the aircraft model. An error bound on fault effect parameter estimation is provided, within which the Lyapunov stability of the closed-loop system is robust. Our simulation results show that as long as the fault parameter estimates are sufficiently accurate, the polytopic controller can provide satisfactory fault-tolerance.

Wu, N. Eva; Ju, Jianhong

2000-01-01

283

Scaling of fault damage zones with displacement and the implications for fault growth processes  

Microsoft Academic Search

Knowledge of the spatial extent of damage surrounding fault zones is important for understanding crustal fluid flow and also for understanding the physical processes and mechanics by which fault zones develop with slip. There are few data available on the scaling of the fault damage zone with fault displacement, and of those that exist, deriving scaling relationships is hampered by

D. R. Faulkner; T. M. Mitchell; E. Jensen; J. Cembrano

2011-01-01

284

Neural network based fault diagnosis and fault tolerant control for BLDC motor  

Microsoft Academic Search

A fault diagnostics and fault tolerant control system for controller of brushless direct current motor is designed. The neural network state observer is trained by real nonlinear control system. From the residual difference between outputs of actual system and neural network observer, the fault of control system is detected and determined. The simulation results and study on fault diagnostics are

Zheng Li

2009-01-01

285

Fast Protection of Strong Power Systems With Fault Current Limiters and PLL-Aided Fault Detection  

Microsoft Academic Search

In this paper, a new method is proposed that can be used to discriminate faults from switching transients. The method is primarily intended for use in systems where fast fault detection and fast fault clearing before the first peak of the fault current are required. An industrial system, in which high short-circuit power is desired but in which high short-circuit

Magnus Ohrstrom; Lennart Soder

2011-01-01

286

Curved Fault Dynamic Rupture Study: Wasatch Fault Salt Lake City Segment  

NASA Astrophysics Data System (ADS)

Faults are not planar; the curvature of the fault provides us useful information on the earthquake mechanics and faulting (Scholz, 1990). Fault geometry has a profound impact on both static aspect (stress distribution in the fault zone) and dynamic aspect (facilitation and impedance of the fault rupture process) of some fundamental earthquake problems. In most earthquake simulations, planar/piece-wise planar faults are used for numerical simplicity. For real earthquake scenarios, especially ground motion prediction, the eligibility of using simplified planar fault geometry needs to be validated, otherwise the simplification might bias the final conclusion. We analyze the rupture process and ground motion statistics in earthquake simulations for Wasatch Fault -Salt Lake City segment- with different fault configurations. We use a finite element method (Ma & Liu, 2006) to simulate the dynamics of a propagating rupture. We consider various initial stress distribution schemes on the fault (uniform, depth-dependent, random). We want to understand 1) how does the fault geometry itself influence the physical rupture process? and 2) what effect does the curvature have on redistributing the initial stresses on the fault? We will monitor the Coulomb stress change near the fault (Liu et al, 2010). This may provide some indication of the interaction between discontinuous fault segments and dynamic triggering as well as the distribution of aftershocks/foreshocks in relation to the fault geometry.

Liu, Q.; Archuleta, R. J.; Smith, R. B.

2011-12-01

287

Migrating Fault Trees To Decision Trees For Real Time Fault Detection On International Space Station  

Microsoft Academic Search

Fault Tree Analysis shows the possible causes of a system malfunction by enumerating the suspect components and their respective failure modes that may have induced the problem. Complex systems often use fault trees to analyze the faults. Fault diagnosis, when error occurs, is performed by engineers and analysts performing extensive examination of all data gathered during the mission. International Space

Charles Lee; Richard L. Alena; Peter Robinson

2005-01-01

288

Paleomagnetic Data From the Rinconada Fault in Central California: Evidence for Off-fault Deformation  

Microsoft Academic Search

The Rinconada fault is one of three major sub-parallel faults of the San Andreas fault system in central California. The fault has 18 km of dextral displacement since the Pliocene and up to 60 km of total displacement for the Tertiary. A fold and thrust best is well developed in Miocene and younger sedimentary rocks on either side of the

S. Crump; S. Titus; Z. McGuire; B. A. Housen

2009-01-01

289

Fault-tolerant wormhole routing in tori  

Microsoft Academic Search

We present a method to enhance wormhole routing algorithms for deadlock-free fault-tolerant routing in tori. We consider arbitrarily-located faulty blocks and assume only local knowledge of faults. Messages are routed via shortest paths when there are no faults, and this constraint is only slightly relaxed to facilitate routing in the presence of faults. The key concept we use is that,

Suresh Chalasani; Rajendra V. Boppana

1994-01-01

290

Low Angle Normal Fault, Fossil or Active?  

NASA Astrophysics Data System (ADS)

The Panamint Valley - Hunter Mountain - Saline Range (PHS) faults are, together with the Death Valley and Owens Valley faults, one of the three major fault zones within the Eastern California Shear Zone (ECSZ). The ECSZ is the most active fault system bounding the Basin and Range to the southwest with approximately 10 mm/yr of cumulative slip along strike-slip and trans-tensional segments. Previous work has identified the Panamint Valley and Saline Range faults as low angle normal faults and the Hunter Mountain as a transfer fault (Wesnousky and Jones, 1994). A debate exists whether this system is active at present time. Interferometry Synthetic Aperture Radar (InSAR) is a geodetic technique that allows measurement of ground motion at a mm/yr accuracy over large areas with a high measurement sampling. We processed a large number of data to investigate ground motion in the PHS fault system to shed light on the interseismic strain accumulation and its relation to the fault geometry. Preliminary results indicate high strain rate over the Hunter Mountain fault. The locking depth of the fault inferred from elastic modeling of interseismic strain accumulation is on the order of 4km, significantly shallower than for neighboring faults. In contrast, the long wavelength strain field across the Panamint and Saline faults indicates possibly deeper locking depths and/or shallower dip. The shallow locking depth of 4km inferred for the Hunter Mountain fault corresponds with the extension at depth of the two bounding low angle normal faults below Hunter Mountain, suggesting a control by the low angle normal fault system.

Gourmelen, N.; Falk, A.; Manzo, M.; Francesco, C.; Lanari, R.; Johnson, K.

2007-12-01

291

Automatic fault diagnosis of a switching regulator  

NASA Astrophysics Data System (ADS)

This paper describes a microprocessor-based system for the automatic fault diagnosis of a switching regulator. It covers the system from a test philosophy to a working breadboard that correctly identifies single simulated faults in the switching regulator. In addition to open circuit, short circuit, and stuck at faults, the system is capable of diagnosing faults due to excessive leakage, drift in critical components, and system instability.

Nienhaus, H. A.; Palmer, D. E.

292

Slip localization and fault weakening as a consequence of fault gouge strengthening — Insights from laboratory experiments  

NASA Astrophysics Data System (ADS)

A laboratory study of simulated quartz gouges was conducted to investigate how solution transfer processes influence the mechanical behaviour of fault wear products at high temperature, hydrothermal conditions. Experiments were performed under nominally dry conditions, as well as in the presence of an aqueous pore fluid, at elevated temperatures (500 to 927 °C), and at effective confining pressure conditions ( ?2' = ?3' = 100 MPa) to simulate, on a laboratory timescale, processes that may be important in fluid-active fault zones at depth in the continental crust. The mechanical data and microstructural analysis indicate that the kinetics of solution transfer processes can exert a fundamental control on the mechanical behaviour of fault wear products. It is found that, at nominally dry conditions, gouges deform by cataclastic creep and distributed shear, with strength and microstructures being relatively unaffected by temperature. At moderately chemically reactive, hydrothermal conditions (500-600 °C, coarse grain size, or fast deformation rate), the presence of a reactive pore fluid slightly reduces the shear strength with respect to dry conditions. However, at highly chemically reactive, hydrothermal conditions (600-927 °C, small grain size, and slow deformation rate), rapid porosity reduction is accommodated by dissolution-precipitation processes. Deformation under such conditions results in a fast increase of grain contact area and the development of cohesive bonds between adjacent particles, which in turn inhibits cataclastic granular flow. With increasing displacement and compaction of the quartz gouge, there is a sudden transition from distributed cataclastic flow, to slip localization at the interface between the gouge and one of the forcing blocks. This deformation mode switch is associated with dramatic weakening (up to 50% drop in shear resistance, and changes in the apparent coefficient of friction from > 0.7 to ? 0.4). Stress drop occurs over many minutes in the laboratory. It is speculated that solution-assisted gouge compaction, and consequent slip localization with associated slow, yet dramatic stress drop, could provide a mechanism for the occurrence of slow earthquakes.

Giger, Silvio B.; Cox, Stephen F.; Tenthorey, Eric

2008-11-01

293

Mechanical Role of Fluids in Earthquakes and Faulting  

NASA Astrophysics Data System (ADS)

Following the contributions of Hubbert and Rubey, the level of ambient pore pressure is of accepted importance for understanding the static frictional strength of faults. There are also important dynamical interactions between pore fluids and faulting. Some of those are addressed here, with examples to be chosen from the following: (1) Pore fluid presence at full saturation promotes strong localization in rapidly shearing granular materials, even in cases for which the friction coefficient increases rapidly with shearing rate [see Rice, Rudnicki and Tsai, this meeting]. (2) Thermal pressurization of earthquake faults during seismic slip may provide the primary weakening process during earthquakes in mature crustal fault zones; it provides a plausible basic explanation, based on geological and laboratory data, of the magnitudes of the fracture energies of earthquakes as inferred independently from seismological data [see web link below]. The process also seems to be active in some large landslides. (3) Pore pressure alterations are induced by rapid mode II slip on fault planes when they have bordering gouge or damage zones which are of dissimilar permeability and/or poroelastic properties. This provides a fuller, new perspective on effects of material dissimilarity across a slip surface on altering the effective normal stress and thus interacting with dynamic rupture [see Rudnicki and Rice, this meeting]. (4) Gouge dilatancy associated with slip-rate increases induces suction in the pore fluid, so as to partially stabilize faults against earthquake nucleation, and also to slow rupture propagation into shallow fault regions. An open question is that of when and if shear heating acts to aid nucleation; the effect seems negligible for nucleation under slow tectonic loading but may be important for nucleation driven by sudden steps in stress. (5) Permeability determines pore pressure gradients for given flow rates, but increases in pore pressure cause increases in permeability. That allows slow solitary waves of pore pressure increase which propagate upwards against gravity in fault zones that are reasonably sealed from their surroundings, following initiation by, e.g., breaching of a pressurized seal at depth. (6) Aseismic slip transients in subduction zones occur in an environment of active compaction and metamorphic fluid release, and fluids seem responsible for associated tremor as well. Recent modeling [see Liu and Rice, this meeting] links elevation of fluid pressure to the speed of along-strike propagation of slip transients. (7) Poroelastic responses to stress transfer have been detected for some earthquakes, and associated transient stress changes may play a role in aftershock sequences, although probably secondary in general. (8) Another type of fluid saturated ``fault zone'', in granulated sediments between dissimilar materials, is the bed of a mobile ice sheet. Some of the concepts in topics 1 to 4 above may have application to surges, ice streams, and glacial earthquakes. These various cases 1 to 8 involve many contributors in the geophysical community, and include collaborative current or recent studies of the author with Massimo Cocco (2), Yajing Liu (4, 6), Alan Rempel (2), John Rudnicki (1,3), Paul Segall (4), and Victor Tsai (1,8).

Rice, J. R.

2005-12-01

294

Application of trishear fault-propagation folding to active reverse faults: examples from the Dalong Fault, Gansu Province, NW China  

NASA Astrophysics Data System (ADS)

Determining accurate fault slip rates at 1 ka to 1 Ma timescales requires well-constrained palinspastic reconstructions of dateable geomorphic and/or geologic markers. Although general kinematic models have been developed to simultaneously reconstruct both bedrock (e.g. bedding and fault attitudes) and neotectonic markers (e.g. strath terraces) along active strike-slip and thrust faults, it is not clear if these models can also account for deformation along steeply dipping (>45°) reverse faults. To address this problem, we have investigated the active, ˜50° dipping, Dalong reverse fault system. This ˜40-km-long fault system forms part of the Aksai restraining stepover along the active, left-slip Altyn Tagh Fault in northwestern China. Our geometric and kinematic analyses show that conventional fault-bend fold models cannot satisfy the steeply-dipping fault geometry we observe in the bedrock record. Likewise, standard fault-propagation fold models fail to match our measurements of a set of fluvial terraces. However, by expanding the trishear model of fault-propagation folding to track both bedrock and neotectonic markers, we are able to match both sets of records. In particular, we have developed trishear kinematic models for two sites (Liuchenzi and Qingyazi) using the numerical modeling program, Fault/Fold v.5.0. This work indicates that an important implication of active trishear fault-propagation folding is that terrace deformation extends for over 1 km on either side of the fault trace. Thus, to accurately measure the total magnitude of vertical separation between matching terraces in the hanging wall and footwall, terrace profiles across active reverse faults must extend 1-2 km on either side of this zone of deformation.

Gold, Ryan D.; Cowgill, Eric; Wang, Xiao-Feng; Chen, Xuan-Hua

2006-02-01

295

Dislocation model for aseismic fault slip in the transverse ranges of Southern California  

NASA Technical Reports Server (NTRS)

Geodetic data at a plate boundary can reveal the pattern of subsurface displacements that accompany plate motion. These displacements are modelled as the sum of rigid block motion and the elastic effects of frictional interaction between blocks. The frictional interactions are represented by uniform dislocation on each of several rectangular fault patches. The block velocities and fault parameters are then estimated from geodetic data. Bayesian inversion procedure employs prior estimates based on geological and seismological data. The method is applied to the Transverse Ranges, using prior geological and seismological data and geodetic data from the USGS trilateration networks. Geodetic data imply a displacement rate of about 20 mm/yr across the San Andreas Fault, while the geologic estimates exceed 30 mm/yr. The prior model and the final estimates both imply about 10 mm/yr crustal shortening normal to the trend of the San Andreas Fault. Aseismic fault motion is a major contributor to plate motion. The geodetic data can help to identify faults that are suffering rapid stress accumulation; in the Transverse Ranges those faults are the San Andreas and the Santa Susana.

Cheng, A.; Jackson, D. D.; Matsuura, M.

1985-01-01

296

Study on fault induced rock bursts  

Microsoft Academic Search

In order to study the rules of rock bursts caused by faults by means of mechanical analysis of a roof rock-mass balanced structure and numerical simulation about fault slip destabilization, the effect of coal mining operation on fault plane stresses and slip displacement were studied. The results indicate that the slip displacement sharply increases due to the decrease of normal

Zhi-hua LI; Lin-ming DOU; Cai-ping LU; Zong-long MU; An-ye CAO

2008-01-01

297

Active faulting and tectonics in China  

Microsoft Academic Search

We present a study of the active tectonics of China based on an interpretation of Landsat (satellite) imagery and supplemented with seismic data. Several important fault systems can be identified, and most are located in regions of high historical seismicity. We deduce the type and sense of faulting from adjacent features seen on these photos, from fault plane solutions of

Paul Tapponnier; Peter Molnar

1977-01-01

298

Short failure analysis under fault isolation  

Microsoft Academic Search

Scanning superconducting quantum interference device (SQUID) microscopy, along with real time X-ray (RTX) microscopy and scanning acoustic microscopy (SAM), was used as a fault isolation tool for IC short circuit failure analysis. Fault isolation was carried out before physical analysis. Experimental procedures and results for both fault isolation and physical analysis are given in detail

Z. H. Mai; M. Palaniappan; J. M. Chin; C. E. Soh; L. A. Knauss; E. F. Fleet

2001-01-01

299

High temperature superconducting fault current limiter  

DOEpatents

A fault current limiter for an electrical circuit is disclosed. The fault current limiter includes a high temperature superconductor in the electrical circuit. The high temperature superconductor is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter. 15 figs.

Hull, J.R.

1997-02-04

300

High temperature superconducting fault current limiter  

DOEpatents

A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

Hull, John R. (Hinsdale, IL)

1997-01-01

301

Lithospheric elasticity promotes episodic fault activity  

Microsoft Academic Search

Based on the agreement between geodetic and geological plate velocities, interplate fault slip rates are usually considered constant over long periods of time. However, measurements made at different time scales on intracontinental faults suggest that slip rate evolves with time. We examine the slip evolution of a fault embedded in an elastic lithosphere loaded by plate motion. We first assume

Jean Chéry; Philippe Vernant

2006-01-01

302

FAULT & COORDINATION STUDY FOR T PLANT COMPLEX  

SciTech Connect

A short circuit study is performed to determine the maximum fault current that the system protective devices, transformers, and interconnections would he subject to in event of a three phase, phase-to-phase, or phase-to-ground fault. Generally, the short circuit study provides the worst case fault current levels at each bus or connection point of the system.

MCDONALD, G.P.; BOYD-BODIAU, E.A.

2004-09-01

303

Predicting Where Faults Can Hide from Testing  

Microsoft Academic Search

Sensitivity analysis, which estimates the probability that a program location can hide a failure-causing fault, is addressed. The concept of sensitivity is discussed, and a fault\\/failure model that accounts for fault location is presented. Sensitivity analysis requires that every location be analyzed for three properties: the probability of execution occurring, the probability of infection occurring, and the probability of propagation

Jeffrey M. Voas; Larry J. Morell; Keith W. Miller

1991-01-01

304

Recurrent Faults in Objective Test Items.  

ERIC Educational Resources Information Center

A study of recurrent faults in multiple-choice items in Britain's Open University's computer-marked tests has led to a procedure for avoiding these faults. A description of the study covers the incidence and sources of faults (obviousness, memorization, unclear instruction, ambiguity, distractors, inter-item effects, and structure) and…

Stratton, N. J.

1981-01-01

305

Path delay fault simulation of sequential circuits  

Microsoft Academic Search

To analyze path delay faults in synchronous sequential circuits, stimuli are simulated in a dual-vector mode. The signal states represent the logic and transition conditions for two consecutive vectors. After the simulation of each vector, only the activated paths are traced and the corresponding fault effect, if propagated to a flip-flop, is added to its fault list. A path numbering

Soumitra Bose; Prathima Agrawal; Vishwani D. Agrawal

1993-01-01

306

Fault tolerant software modules for SIFT  

NASA Technical Reports Server (NTRS)

The implementation of software fault tolerance is investigated for critical modules of the Software Implemented Fault Tolerance (SIFT) operating system to support the computational and reliability requirements of advanced fly by wire transport aircraft. Fault tolerant designs generated for the error reported and global executive are examined. A description of the alternate routines, implementation requirements, and software validation are included.

Hecht, M.; Hecht, H.

1982-01-01

307

Field Trip to the Hayward Fault Zone  

NSDL National Science Digital Library

This guide provides directions to locations in Hayward, California where visitors can see evidence of creep along the Hayward Fault. There is also information about the earthquake hazards associated with fault zones, earthquake prediction, and landforms associated with offset along a fault. The guide is available in downloadable, printable format (PDF) in two resolutions

308

Fault-Tolerance in Universal Middleware Bridge  

Microsoft Academic Search

Universal middleware bridge (UMB) provides seamless interoperation among heterogeneous home network middleware. There have been high demands for the UMB components (UMB core and adaptors) to have fault- tolerance capabilities. This paper presents a TMO structuring approach together with new implementation techniques for the fault-tolerant TMO-replica structuring scheme called PSTR. PSTR implementations of UMB components provide fault tolerance capabilities essential

Kyung-deok Moon; Jun Hee Park; Liangchen Zheng; Qian Zhou

2008-01-01

309

Information Survivability, Security, and Fault Tolerance  

Microsoft Academic Search

Unlike traditional fault tolerant computing, fault tolerant computing in support of infor- mation survivability must provide access to information in the face of attacks on integrity and availability. One large class of fault tolerant techniques uses a quorum of redundant components to determine what the \\

Matt Bishop

310

Modular approach to fault tree analysis  

Microsoft Academic Search

An analytical method to describe fault tree diagrams in terms of their modular composition is developed. Fault tree structures are characterized by recursively relating the top tree event to all its basic component inputs through a set of equations defining each of the modules for the fault tree. It is shown that such a modular description is an extremely valuable

J. Olmes; L. Wolf

1977-01-01

311

Formal methodology for fault tree construction  

Microsoft Academic Search

A model is presented for formulating the Boolean failure logic, cailed ; the fault tree, for electrical systems from associated schematic diagrams and ; system-independent component information. The model is developed in detail for ; electrical systems, while its implication and terminology extend to all fault ; tree construction. The methodology is verified as formal by fault trees ; constructed

Fussell

1973-01-01

312

Cottage Grove Fault System in Southern Illinois.  

National Technical Information Service (NTIS)

The Cottage Grove Fault System is one of the major tectonic fault systems in southern Illinois. It extends from the Saline-Gallatin County line westward at least as far as Campbell Hill in Jackson County, a distance of about 70 miles. The zone of faulting...

W. J. Nelson H. F. Krausse H. M. Bristol

1981-01-01

313

A fault simulator for MOS LSI circuits  

Microsoft Academic Search

This paper describes a fault simulator for MOS LSI circuits. The basic primitives for this simulator are MOS transistor structures where the transistors are evaluated logically. The simulator provides the capability of modeling and simulating both the classical input\\/output stuck-at faults and the nonclassical transistor stuck-on and stuck-open faults.

A. K. Bose; P. Kozak; C.-Y. Lo; H. N. Nham; E. Pacas-Skewes

1988-01-01

314

A fault simulator for MOS LSI circuits  

Microsoft Academic Search

This paper describes a fault simulator for MOS LSI circuits. The basic primitives for this simulator are MOS transistor structures where the transistors are evaluated logically. The simulator provides the capability of modeling and simulating both the classical input\\/output stuck-at faults and the non-classical transistor stuck-on and stuck-open faults.

A. K. Bose; P. Kozak; C.-Y. Lo; H. N. Nham; E. Pacas-Skewes; K. Wu

1982-01-01

315

On fault detection in CMOS logic networks  

Microsoft Academic Search

This paper considers the problem of detecting faults in CMOS combinational networks. Effects of open and short faults in CMOS networks are analyzed. It is shown that the test sequence must be properly organized if the effects of all open faults are to be observable at the network output terminal. A simple and efficient heuristic method for organizing the test

Kuang-Wei Chiang; Zvonko G. Vranesic

1983-01-01

316

SOFTWARE EVOLUTION AND THE FAULT PROCESS  

Microsoft Academic Search

In developing a software system, we would like to estimate the way in which the fault content changes during its development, as well determine the locations having the highest concentration of faults. In the phases prior to test, however, there may be very little direct in- formation regarding the number and location of faults. This lack of direct information requires

John C. Munson

1998-01-01

317

Estimating Software Fault Content Before Coding  

Microsoft Academic Search

The standard software development process consists of multiple stages: requirements. design, coding, system test, first office. and finally delivery. An objective of this process is to minimize the number of faults in delivered code. Root cause analysis shows that many of the faults can be traced back to requirements or design faults. As part of the software development process, reviews

S. G. Eickt; Clive R. Loader; M. D. Long; Lawrence G. Votta; S. V. Wiel

1992-01-01

318

An empirical investigation of software fault distribution  

Microsoft Academic Search

The paper investigates the distribution of faults within three evolutionary versions or releases of a system software product. A greater concentration of faults was found in certain software program modules as compared to other modules. The fault rates are correlated to the percentage of new and changed lines of code, the module size, and the programming languages used. Additionally, a

Karl-Heinrich Moller; Daniel J. Paulish

1993-01-01

319

Estimating software fault content before coding  

Microsoft Academic Search

The standard software development process consists of multiple stages: requirements, design, coding, system test, first office, and finally delivery. An objective of this process is to minimize the number of faults in delivered code. Root cause analysis shows that many of the faults can be traced back to requirements or design faults. As part of the software development process, reviews

Stephen G. Eick; Clive R. Loader; M. David Long; Lawrence G. Votta; Scott A. Vander Wiel

1992-01-01

320

Measurement and application of fault latency  

NASA Technical Reports Server (NTRS)

The time interval between the occurrence of a fault and the detection of the error caused by the fault is divided by the generation of that error into two parts: fault latency and error latency. Since the moment of error generation is not directly observable, all related works in the literature have dealt with only the sum of fault and error latencies, thereby making the analysis of their separate effects impossible. To remedy this deficiency, (1) a new methodology for indirectly measuring fault latency is presented; the distribution of fault latency is derived from the methodology; and (3) the knowledge of fault latency is applied to the analysis of two important examples. The proposed methodology has been implemented for measuring fault latency in the Fault-Tolerant Multiprocessor (FTMP) at the NASA Airlab. The experimental results show wide variations in the mean fault latencies of different function circuits within FTMP. Also, the measured distributions of fault latency are shown to have monotone hazard rates. Consequently, Gamma and Weibull distributions are selected for the least-squares fit as the distribution of fault latency.

Shin, K. G.; Lee, Y.-H.

1986-01-01

321

COMMENTS ON STACKING FAULT ENERGY OF THORIUM  

Microsoft Academic Search

Transmission electron microscopic studies were made of foils made from ; cold-rolled thorium sheet. Tangled dislocations forming a crude cell structure ; were observed, but no fringes characteristic of stacking faults were visible. No ; example of cross-slip was observed. The results suggest that thorium has an ; intermediate stacking fault energy. The interpretation of stacking fault ; probability as

J. O. Stiegler; C. J. McHargue

1963-01-01

322

On-line fault diagnosis of power substation using connectionist expert system  

SciTech Connect

This paper proposes a new connectionist (or neural network) expert system for on-line fault diagnosis of a power substation. The Connectionist Expert Diagnosis System has similar profile of an expert system, but can be constructed much more easily from elemental samples. These samples associate the faults with their protective relays and breakers as well as the bus voltages and feeder currents. Through an elaborately designed structure, alarm signals are processed by different connectionist models. The output of the connectionist models is then integrated to provide the final conclusion with a confidence level. The proposed approach has been practically verified by testing on a typical Taiwan Power (Taipower) secondary substation. The test results show that rapid and exactly correct diagnosis is obtained even for the fault conditions involving multiple faults or failure operation of protective relay and circuit breaker. Moreover, the system can be transplanted into various substations with little additional implementation effort.

Yang, H.T.; Chang, W.Y.; Huang, C.L. [National Cheng Kung Univ., Tainan (Taiwan, Province of China). Dept. of Electrical Engineering

1995-02-01

323

Unified Fault-Tolerance Protocol.  

National Technical Information Service (NTIS)

Davies and Wakerly show that Byzantine fault tolerance can be achieved by a cascade of broadcasts and middle value select functions. We present an extension of the Davies and Wakerly protocol, the unified protocol, and its proof of correctness. We prove t...

P. Miner A. Gedser L. Pike J. Maddalon

2004-01-01

324

Reflection Survey at Barracuda Fault.  

National Technical Information Service (NTIS)

This paper presents the results of a reconnaissance survey conducted by Western Geophysical Company over the Barracuda Fault structure, which is located about 200 miles east of Guadeloupe Island in the West Indies. This was one of the areas selected for e...

L. Paitson C. H. Savit D. M. Blue W. A. Knox

1965-01-01

325

Cell boundary fault detection system  

DOEpatents

An apparatus and program product determine a nodal fault along the boundary, or face, of a computing cell. Nodes on adjacent cell boundaries communicate with each other, and the communications are analyzed to determine if a node or connection is faulty.

Archer, Charles Jens (Rochester, MN) [Rochester, MN; Pinnow, Kurt Walter (Rochester, MN) [Rochester, MN; Ratterman, Joseph D. (Rochester, MN) [Rochester, MN; Smith, Brian Edward (Rochester, MN) [Rochester, MN

2011-04-19

326

Software Fault Tolerance: A Tutorial  

Microsoft Academic Search

Because of our present inability to produce error-freesoftware, software fault tolerance is and will continue to be animportant consideration in software systems. The root cause ofsoftware design errors is the complexity of the systems.Compounding the problems in building correct software is thedifficulty in assessing the correctness of software for highlycomplex systems. This paper presents a review of software faulttolerance. After

Wilfredo Torres-Pomales

2000-01-01

327

SWIFT: Software Implemented Fault Tolerance  

Microsoft Academic Search

To improve performance and reduce power, processor designers employ advances that shrink feature sizes, lower voltage levels, reduce noise margins, and increase clock rates. However, these advances make processors more susceptible to transient faults that can affect correctness. While reliable systems typically employ hardware techniques to address soft-errors, software techniques can provide a lower-cost and more flexible alternative. This paper

George A. Reis; Jonathan Chang; Neil Vachharajani; Ram Rangan; David I. August

2005-01-01

328

SIFT: software implemented fault tolerance  

Microsoft Academic Search

Many computer applications have stringent requirements for continued correct operation of the computer in the presence of internal faults. The subject of design of such highly reliable computers has been extensively studied, and numerous techniques have been developed to achieve this high reliability. Such computers are termed \\

John H. Wensley

1972-01-01

329

Fault-crossing P delays, epicentral biasing, and fault behavior in Central California  

USGS Publications Warehouse

The P delays across the San Andreas fault zone in central California have been determined from travel-time differences at station pairs spanning the fault, using off-fault local earthquake or quarry blast sources. Systematic delays as large as 0.4 sec have been observed for paths crossing the fault at depths of 5-10 km. These delays can account for the apparent deviation of epicenters from the mapped fault trace. The largest delays occur along the San Andreas fault between San Juan Bautista and Bear Valley and Between Bitterwater Valley and Parkfield. Spatial variations in fault behavior correlate with the magnitude of the fault-crossing P delay. The delay decreases to the northwest of San Juan Bautista across the "locked" section of the San Andreas fault and also decreases to the southeast approaching Parkfield. Where the delay is large, seismicity is relatively high and the fault is creeping. ?? 1979.

Marks, S. M.; Bufe, C. G.

1979-01-01

330

The Heart Mountain fault: Implications for the dynamics of decollement  

NASA Astrophysics Data System (ADS)

The Hart Mountain docollement in Northwestern Wyoming originally comprised a plate of rock up to 750m thick and 1300 sq kilometers in area. This plate moved rapidly down a slope no steeper than 2 deg. during Early Eocene time, transporting some blocks at least 50m from their original positions. Sliding occurred just before a volcanic erruption and was probably accompanied by seismic events. The initial movement was along a bedding plane fault in the Bighorn Dolomite, 2 to 3 meters above its contact with the Grove Creek member of the Snowy Range formation. The major pecularity of this fault is that it lies in the strong, cliff-forming Bighorn Dolomite, rather than in the weaker underlying shales. The dynamics of decollement are discussed.

Melosh, H. J.

331

A Fault Injection Technique for VHDL Behavioral-Level Models  

Microsoft Academic Search

Fault injection is an important technique for the evaluation of design metrics such as reliability,safety, and fault coverage. Fault injection involves inserting faults into a system and monitoringthe system to determine its behavior in response to the fault. Recently, designers are realizingthe advantages of using simulation to perform fault injection on a model of the design, as opposedto performing the

Todd A. Delong; Barry W. Johnson; Joseph A. Profeta III

1996-01-01

332

Facies composition and scaling relationships of extensional faults in carbonates  

Microsoft Academic Search

Fault seal evaluations in carbonates are challenged by limited input data. Our analysis of 100 extensional faults in shallow-buried layered carbonate rocks aims to improve forecasting of fault core characteristics in these rocks. We have analyzed the spatial distribution of fault core elements described using a Fault Facies classification scheme; a method specifically developed for 3D fault description and quantification,

Eivind Bastesen; Alvar Braathen

2010-01-01

333

Earthquake scaling relations for mid-ocean ridge transform faults  

NASA Astrophysics Data System (ADS)

A mid-ocean ridge transform fault (RTF) of length L, slip rate V, and moment release rate ? can be characterized by a seismic coupling coefficient ? = AE/AT, where AE ˜ ?/V is an effective seismic area and AT ? L3/2V-1/2 is the area above an isotherm Tref. A global set of 65 RTFs with a combined length of 16,410 km is well described by a linear scaling relation (1) AE ? AT, which yields ? = 0.15 ± 0.05 for Tref = 600°C. Therefore about 85% of the slip above the 600°C isotherm must be accommodated by subseismic mechanisms, and this slip partitioning does not depend systematically on either V or L. RTF seismicity can be fit by a truncated Gutenberg-Richter distribution with a slope ? = 2/3 in which the cumulative number of events N0 and the upper cutoff moment MC = ?DCAC depend on AT. Data for the largest events are consistent with a self-similar slip scaling, DC ? AC1/2, and a square root areal scaling (2) AC ? AT1/2. If relations 1 and 2 apply, then moment balance requires that the dimensionless seismic productivity, ?0 ? ?0/ATV, should scale as ?0 ? AT-1/4, which we confirm using small events. Hence the frequencies of both small and large earthquakes adjust with AT to maintain constant coupling. RTF scaling relations appear to violate the single-mode hypothesis, which states that a fault patch is either fully seismic or fully aseismic and thus implies AC ? AE. The heterogeneities in the stress distribution and fault structure responsible for relation 2 may arise from a thermally regulated, dynamic balance between the growth and coalescence of fault segments within a rapidly evolving fault zone.

Boettcher, M. S.; Jordan, T. H.

2004-12-01

334

Late Holocene earthquakes on the Toe Jam Hill fault, Seattle fault zone, Bainbridge Island, Washington  

Microsoft Academic Search

Five trenches across a Holocene fault scarp yield the first radiocarbon-measured earthquake recurrence intervals for a crustal fault in western Washington. The scarp, the first to be revealed by laser im- agery, marks the Toe Jam Hill fault, a north-dipping backthrust to the Seattle fault. Folded and faulted strata, liquefac- tion features, and forest soil A horizons buried by hanging-wall-collapse

Alan R. Nelson; Samuel Y. Johnson; Harvey M. Kelsey; Ray E. Wells; Brian L. Sherrod; Silvio K. Pezzopane; Lee-Ann Bradley; Rich D. Koehler; Robert C. Bucknam

2003-01-01

335

Dynamic fault-tree models for fault-tolerant computer systems  

Microsoft Academic Search

Reliability analysis of fault-tolerant computer systems for critical applications is complicated by several factors. Systems designed to achieve high levels of reliability frequently employ high levels of redundancy, dynamic redundancy management, and complex fault and error recovery techniques. This paper describes dynamic fault-tree modeling techniques for handling these difficulties. Three advanced fault-tolerant computer systems are described: a fault-tolerant parallel processor,

Joanne Bechta Dugan; Salvatore J. Bavuso; Mark A. Boyd

1992-01-01

336

Architecture of small-scale fault zones in the context of the Leinetalgraben Fault System  

Microsoft Academic Search

Understanding fault zone properties in different geological settings is important to better assess the development and propagation of faults. In addition this allows better evaluation and permeability estimates of potential fault-related geothermal reservoirs. The Leinetalgraben fault system provides an outcrop analogue for many fault zones in the subsurface of the North German Basin. The Leinetalgraben is a N-S-trending graben structure,

Dorothea Reyer; Sonja L. Philipp

2010-01-01

337

Dealing with dormant faults in an embedded fault-tolerant computer system  

Microsoft Academic Search

Accumulation of dormant faults is a potential threat in a fault tolerant system, especially because most often fault tolerance is based on the single-fault assumption. We investigate this threat by the example of an automotive steer-by-wire application based on the Time-Triggered Architecture (TTA). By means of a Markov model we illustrate that the effect of fault dormancy can degrade the

C. Scherrer; A. Steininger

2003-01-01

338

Fault Diagnosis in HVAC Chillers  

NASA Technical Reports Server (NTRS)

Modern buildings are being equipped with increasingly sophisticated power and control systems with substantial capabilities for monitoring and controlling the amenities. Operational problems associated with heating, ventilation, and air-conditioning (HVAC) systems plague many commercial buildings, often the result of degraded equipment, failed sensors, improper installation, poor maintenance, and improperly implemented controls. Most existing HVAC fault-diagnostic schemes are based on analytical models and knowledge bases. These schemes are adequate for generic systems. However, real-world systems significantly differ from the generic ones and necessitate modifications of the models and/or customization of the standard knowledge bases, which can be labor intensive. Data-driven techniques for fault detection and isolation (FDI) have a close relationship with pattern recognition, wherein one seeks to categorize the input-output data into normal or faulty classes. Owing to the simplicity and adaptability, customization of a data-driven FDI approach does not require in-depth knowledge of the HVAC system. It enables the building system operators to improve energy efficiency and maintain the desired comfort level at a reduced cost. In this article, we consider a data-driven approach for FDI of chillers in HVAC systems. To diagnose the faults of interest in the chiller, we employ multiway dynamic principal component analysis (MPCA), multiway partial least squares (MPLS), and support vector machines (SVMs). The simulation of a chiller under various fault conditions is conducted using a standard chiller simulator from the American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE). We validated our FDI scheme using experimental data obtained from different types of chiller faults.

Choi, Kihoon; Namuru, Setu M.; Azam, Mohammad S.; Luo, Jianhui; Pattipati, Krishna R.; Patterson-Hine, Ann

2005-01-01

339

Fault-Tolerant Heat Exchanger  

NASA Technical Reports Server (NTRS)

A compact, lightweight heat exchanger has been designed to be fault-tolerant in the sense that a single-point leak would not cause mixing of heat-transfer fluids. This particular heat exchanger is intended to be part of the temperature-regulation system for habitable modules of the International Space Station and to function with water and ammonia as the heat-transfer fluids. The basic fault-tolerant design is adaptable to other heat-transfer fluids and heat exchangers for applications in which mixing of heat-transfer fluids would pose toxic, explosive, or other hazards: Examples could include fuel/air heat exchangers for thermal management on aircraft, process heat exchangers in the cryogenic industry, and heat exchangers used in chemical processing. The reason this heat exchanger can tolerate a single-point leak is that the heat-transfer fluids are everywhere separated by a vented volume and at least two seals. The combination of fault tolerance, compactness, and light weight is implemented in a unique heat-exchanger core configuration: Each fluid passage is entirely surrounded by a vented region bridged by solid structures through which heat is conducted between the fluids. Precise, proprietary fabrication techniques make it possible to manufacture the vented regions and heat-conducting structures with very small dimensions to obtain a very large coefficient of heat transfer between the two fluids. A large heat-transfer coefficient favors compact design by making it possible to use a relatively small core for a given heat-transfer rate. Calculations and experiments have shown that in most respects, the fault-tolerant heat exchanger can be expected to equal or exceed the performance of the non-fault-tolerant heat exchanger that it is intended to supplant (see table). The only significant disadvantages are a slight weight penalty and a small decrease in the mass-specific heat transfer.

Izenson, Michael G.; Crowley, Christopher J.

2005-01-01

340

The occurrence of graphite-bearing fault rocks in the Atotsugawa fault system, Japan: Origins and implications for fault creep  

NASA Astrophysics Data System (ADS)

Graphite in fault zones has received little attention even though it is a well-known solid lubricant that could affect frictional properties of faults dramatically. This paper reports the presence of abundant graphite in fault zones of the Atotsugawa fault system, central Japan. Mesoscopic and microscopic observations of fault rocks revealed two processes of carbon enrichment in fault zones. One is a pressure solution process or diffusive mass transfer in general which removes water-soluble minerals such as quartz and carbonates from rocks, resulting in the enrichment of insoluble minerals including carbon. The other process is precipitation of graphite from a high-temperature carbon-rich fluid, forming graphite filling fractures within cataclasitic fault zones. The two processes have led to the concentration, up to 12 wt% of graphite, in the Atotsugawa fault zones, compared to 0 to 3 wt% of carbonaceous materials in the host rocks. This concentration is high enough for graphite to affect frictional properties at wide range of slip rates. The presence of graphite may provide an explanation for the low resistivity, the patterns of microearthquakes and fault creep along the western part of the Atotsugawa fault system. Graphite should receive more attention as a weakening and stabilizing agent of faults.

Oohashi, Kiyokazu; Hirose, Takehiro; Kobayashi, Kenta; Shimamoto, Toshihiko

2012-05-01

341

Fault tolerant high-performance PACS network design and implementation  

NASA Astrophysics Data System (ADS)

The Wake Forest University School of Medicine and the Wake Forest University/Baptist Medical Center (WFUBMC) are implementing a second generation PACS. The first generation PACS provided helpful information about the functional and temporal requirements of the system. It highlighted the importance of image retrieval speed, system availability, RIS/HIS integration, the ability to rapidly view images on any PACS workstation, network bandwidth, equipment redundancy, and the ability for the system to evolve using standards-based components. This paper deals with the network design and implementation of the PACS. The physical layout of the hospital areas served by the PACS, the choice of network equipment and installation issues encountered are addressed. Efforts to optimize fault tolerance are discussed. The PACS network is a gigabit, mixed-media network based on LAN emulation over ATM (LANE) with a rapid migration from LANE to Multiple Protocols Over ATM (MPOA) planned. Two fault-tolerant backbone ATM switches serve to distribute network accesses with two load-balancing 622 megabit per second (Mbps) OC-12 interconnections. The switch was sized to be upgradable to provide a 2.54 Gbps OC-48 interconnection with an OC-12 interconnection as a load-balancing backup. Modalities connect with legacy network interface cards to a switched-ethernet device. This device has two 155 Mbps OC-3 load-balancing uplinks to each of the backbone ATM switches of the PACS. This provides a fault-tolerant logical connection to the modality servers which pass verified DICOM images to the PACS servers and proper PACS diagnostic workstations. Where fiber pulls were prohibitively expensive, edge ATM switches were installed with an OC-12 uplink to a backbone ATM switches. The PACS and data base servers are fault-tolerant, hot-swappable Sun Enterprise Servers with an OC-12 connection to a backbone ATM switch and a fast-ethernet connection to a back-up network. The workstations come with 10/100 BASET autosense cards. A redundant switched-ethernet network will be installed to provide yet another degree of network fault-tolerance. The switched-ethernet devices are connected to each of the backbone ATM switches with two-load-balancing OC-3 connections to provide fault-tolerant connectivity in the event of a primary network failure.

Chimiak, William J.; Boehme, Johannes M.

1998-07-01

342

Predeployment validation of fault-tolerant systems through software-implemented fault insertion  

NASA Technical Reports Server (NTRS)

Fault injection-based automated testing (FIAT) environment, which can be used to experimentally characterize and evaluate distributed realtime systems under fault-free and faulted conditions is described. A survey is presented of validation methodologies. The need for fault insertion based on validation methodologies is demonstrated. The origins and models of faults, 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 fault-free performance data and then characterizing the behavior of the system with faults present. Fault insertion is accomplished through software and allows faults or the manifestation of faults to be inserted by either seeding faults into memory or triggering error detection mechanisms. FIAT is capable of emulating a variety of fault-tolerant strategies and architectures, can monitor system activity, and can automatically orchestrate experiments involving insertion of faults. There is a common system interface which allows ease of use to decrease experiment development and run time. Fault 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 fault-tolerance strategy.

Czeck, Edward W.; Siewiorek, Daniel P.; Segall, Zary Z.

1989-01-01

343

Deformation associated with continental normal faults  

NASA Astrophysics Data System (ADS)

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 normal fault illustrate how these secondary structures influence the deformation in ways that are similar to fault/fold geometry mapped in the western Grand Canyon. Specifically, synthetic faults amplify hanging wall bedding dips, antithetic faults reduce dips, and joints act to localize deformation. The distribution of aftershocks in the hanging wall of the Kozani-Grevena earthquake suggests that secondary structures may accommodate strains associated with slip on a master fault during postseismic deformation.

Resor, Phillip G.

344

Detection of faults and software reliability analysis  

NASA Technical Reports Server (NTRS)

Multiversion or N-version programming was proposed as a method of providing fault tolerance in software. The approach requires the separate, independent preparation of multiple versions of a piece of software for some application. Specific topics addressed are: failure probabilities in N-version systems, consistent comparison in N-version systems, descriptions of the faults found in the Knight and Leveson experiment, analytic models of comparison testing, characteristics of the input regions that trigger faults, fault tolerance through data diversity, and the relationship between failures caused by automatically seeded faults.

Knight, J. C.

1986-01-01

345

Rock Friction from the Nanoscale to the San Andreas Fault  

NASA Astrophysics Data System (ADS)

Nucleation of earthquakes (EQs) and the resistance of faults to shearing during EQs are determined by nano-to-micro- scale frictional processes that occur on tectonic-scale faults. A first-order observation from rock-friction studies is that of ageing, i.e., the linear increase in friction with the log of the time of stationary contact, manifest as a positive or negative dependence of friction on sliding rate. A necessary condition for EQ nucleation is a negative rate dependence of friction. In spite of the success of friction `laws' which encapsulate the rate and time dependences of friction in fitting experimental data and reproducing natural phenomena in EQ models, these laws lack a physical basis. Atomic force microscope (AFM) experiments on silica-silica contacts explore the physics of ageing, more specifically increases in adhesion of nanometers-sized contacts with time (Li et al., Nature, 2011). The experiments reveal prominent ageing which increases with humidity, as in rock friction tests, without increases in contact area due to creep (the canonical explanation for ageing in rock-friction tests). Ageing in the AFM tests is in fact much larger than in rock-friction tests, a discrepancy explained with a simple multi-asperity contact model. At EQ slip rates (>=1 m/s) a variety of dynamic fault-weakening mechanisms may decrease the shear resistance of faults, which would have important consequences for the magnitudes of EQ stress drops, strong ground motions and accelerations, for the EQ energy budget, and for the state of stress on faults. Experiments on rocks found in the Earth's crust for slip rates up to ˜0.4 m/s over ˜40 mm of slip, reveal a dramatic 1/V decrease in frictional strength above a characteristic weakening velocity Vw of ˜0.1 m/s (Goldsby and Tullis, Science, 2011). Friction is also revealed to be a nearly pure function of slip rate, i.e., it adjusts to the ambient slip rate over only microns of slip. The observations are explained by `flash heating', whereby microscopic asperity contacts become intensely frictionally heated and weakened above Vw. Dramatically lower friction due to flash heating may explain why heat flow along active faults like the San Andreas Fault is much lower than expected. Strong velocity-weakening friction and the rapid strength recovery with decreasing slip rate from flash heating may explain why EQ ruptures propagate as slip pulses rather than as cracks.

Goldsby, David L.

2012-02-01

346

Rapid shallow breathing  

MedlinePLUS

Tachypnea; Breathing - rapid and shallow; Fast shallow breathing; Respiratory rate - rapid and shallow ... Shallow, rapid breathing has many possible medical causes, including: Asthma Blood clot in an artery in the lung Choking Chronic obstructive ...

347

Expulsion of abnormally pressured fluids along faults  

NASA Astrophysics Data System (ADS)

Numerical simulations of fluid flow and heat transport in the South Eugene Island minibasin, offshore Louisiana, show that expulsion of geopressured fluids along faults can produce temperature and pressure anomalies similar to those observed in the area. In the simulations, abnormally pressured fluid moves along the fault through a fracture network. A thermal anomaly forms adjacent to the fault, while a larger fluid pressure anomaly extends into sediments on either side. Results from constant fault permeability simulations indicate that (1) geopressured sediments must be relatively permeable (5 × 10-17 m2) for expulsion to occur, (2) the size of thermal anomalies depend on the depth to which the fault is hydraulically open, and (3) fluid is vertically transported into shallow sediments when fault permeability is high, while lateral transport along deeper sands dominates when fault permeability is low. Excess fluid pressure in abnormally pressured sediments drops to half its original value throughout much of the minibasin after 10,000 years of expulsion; the associated thermal anomaly is also larger than observations, suggesting expulsion is not continuous. Variable fault permeability simulations, in which compaction of fault zone sediments closes the fracture network, indicate that fault permeability decreases by 1-2 orders of magnitude 1-200 years after expulsion begins. Thermal and baric anomalies from variable permeability simulations are smaller than from constant permeability simulations and are more consistent with available data. Faults must remain permeable for 20-30 years to produce thermal and baric anomalies similar to those observed in the area.

Roberts, Sheila J.; Nunn, Jeffrey A.; Cathles, Larry; Cipriani, Francois-Dominique

1996-12-01

348

Rupture dynamics of a geometrically complex fault  

NASA Astrophysics Data System (ADS)

We study the propagation of a two dimensional antiplane rupture along a complex geometrical fault containing a series of kinks of different angles and intervals between the kinks. Numerical solutions are obtained using the spectral element methods developed by Vilotte, Ampuero and Komatisch. We model both periodically kinked and simple versions of randomly kinked faults. We compare our simulations with the results obtained for rupture propagation along flat faults. We find that geometrically complex differ substantially from flat faults. First, complex faults emit high frequency radiation of ?-2 type every time they encounter geometrical discontinuities, this produces a strong damping of rupture propagation. Second, the average rupture speed along the overall direction of the fault is substantially reduced and, depending on the nature of the geometrical discontinuities, ruptures may be easily stopped. Energy release rates computed assuming that the fault is flat increase as the fault becomes increasingly complex. The stress field around the fault may be described as a corridor of strongly variable stress with patches of stress increase and decrease even if the slip on the fault is continuous. Contrary to flat faults, earthquake propagation leaves behind a complex final state of stress. Our model confirms the experimental findings of many authors who worked on high speed mode I fracture.

Madariaga, R. I.; Ampuero, J.

2005-12-01

349

Model-Based Fault Tolerant Control  

NASA Technical Reports Server (NTRS)

The Model Based Fault Tolerant Control (MBFTC) task was conducted under the NASA Aviation Safety and Security Program. The goal of MBFTC is to develop and demonstrate real-time strategies to diagnose and accommodate anomalous aircraft engine events such as sensor faults, actuator faults, or turbine gas-path component damage that can lead to in-flight shutdowns, aborted take offs, asymmetric thrust/loss of thrust control, or engine surge/stall events. A suite of model-based fault detection algorithms were developed and evaluated. Based on the performance and maturity of the developed algorithms two approaches were selected for further analysis: (i) multiple-hypothesis testing, and (ii) neural networks; both used residuals from an Extended Kalman Filter to detect the occurrence of the selected faults. A simple fusion algorithm was implemented to combine the results from each algorithm to obtain an overall estimate of the identified fault type and magnitude. The identification of the fault type and magnitude enabled the use of an online fault accommodation strategy to correct for the adverse impact of these faults on engine operability thereby enabling continued engine operation in the presence of these faults. The performance of the fault detection and accommodation algorithm was extensively tested in a simulation environment.

Kumar, Aditya; Viassolo, Daniel

2008-01-01

350

Wrench faulting using seismic and Landsat  

SciTech Connect

Two high-multiplicity seismic profiles demonstrate the compressional nature of the faulting along the Double Mountain Lineament in northeast Garza County in the Permian basin. NASA high-altitude aircraft imagery using Landsat parameters delineate the traces of these faults on the surface. The drainage system also defines the fault traces by following the zones of fracture and weakness in the Permian and Triassic outcrops. A north-south seismic profile crosses the Double Mountain lineament (P Shear), defining two thrust faults, two high-angle reverse faults and a pop-up block (flow structure). NASA high-altitude imagery and stream drainage indicate the traces of these faults. The pattern developed fits the definition of left lateral wrench faulting. Overlying carbonate shelf margins are developed above the underlying structure, which further enhances the structural interpretation. An east-west seismic profile 3 mi southeast of the north-south profile again defines the Double Mountain Lineament or P Shear and the associated faulting. A 1-mi wide pop-up block with a high angle reverse fault on both sides demonstrates the compressional nature of the faulting, and the high-altitude imagery delineates the surface traces of the faults. This structure has been drilled with several Stawn and Ellenburger producers, confirming the seismic and surface interpretations in the subsurface.

Bolden, G.P.

1987-05-01

351

Experiments in fault tolerant software reliability  

NASA Technical Reports Server (NTRS)

Twenty functionally equivalent programs were built and tested in a multiversion software experiment. Following unit testing, all programs were subjected to an extensive system test. In the process sixty-one distinct faults were identified among the versions. Less than 12 percent of the faults exhibited varying degrees of positive correlation. The common-cause (or similar) faults spanned as many as 14 components. However, a majority of these faults were trivial, and easily detected by proper unit and/or system testing. Only two of the seven similar faults were difficult faults, and both were caused by specification ambiguities. One of these faults exhibited variable identical-and-wrong response span, i.e. response span which varied with the testing conditions and input data. Techniques that could have been used to avoid the faults are discussed. For example, it was determined that back-to-back testing of 2-tuples could have been used to eliminate about 90 percent of the faults. In addition, four of the seven similar faults could have been detected by using back-to-back testing of 5-tuples. It is believed that most, if not all, similar faults could have been avoided had the specifications been written using more formal notation, the unit testing phase was subject to more stringent standards and controls, and better tools for measuring the quality and adequacy of the test data (e.g. coverage) were used.

Mcallister, David F.; Vouk, Mladen A.

1989-01-01

352

Tool for Viewing Faults Under Terrain  

NASA Technical Reports Server (NTRS)

Multi Surface Light Table (MSLT) is an interactive software tool that was developed in support of the QuakeSim project, which has created an earthquake- fault database and a set of earthquake- simulation software tools. MSLT visualizes the three-dimensional geometries of faults embedded below the terrain and animates time-varying simulations of stress and slip. The fault segments, represented as rectangular surfaces at dip angles, are organized into collections, that is, faults. An interface built into MSLT queries and retrieves fault definitions from the QuakeSim fault database. MSLT also reads time-varying output from one of the QuakeSim simulation tools, called "Virtual California." Stress intensity is represented by variations in color. Slips are represented by directional indicators on the fault segments. The magnitudes of the slips are represented by the duration of the directional indicators in time. The interactive controls in MSLT provide a virtual track-ball, pan and zoom, translucency adjustment, simulation playback, and simulation movie capture. In addition, geographical information on the fault segments and faults is displayed on text windows. Because of the extensive viewing controls, faults can be seen in relation to one another, and to the terrain. These relations can be realized in simulations. Correlated slips in parallel faults are visible in the playback of Virtual California simulations.

Siegel, Herbert, L.; Li, P. Peggy

2005-01-01

353

Multiple Fault Isolation in Redundant Systems  

NASA Technical Reports Server (NTRS)

We consider the problem of sequencing tests to isolate multiple faults in redundant (fault-tolerant) systems with minimum expected testing cost (time). It can be shown that single faults and minimal faults, i.e., minimum number of failures with a failure signature different from the union of failure signatures of individual failures, together with their failure signatures, constitute the necessary information for fault diagnosis in redundant systems. In this paper, we develop an algorithm to find all the minimal faults and their failure signatures. Then, we extend the Sure diagnostic strategies [1] of our previous work to diagnose multiple faults in redundant systems. The proposed algorithms and strategies are illustrated using several examples.

Shakeri, M.; Pattipati, Krishna R.; Raghavan, V.; Patterson-Hine, Ann; Iverson, David L.

1997-01-01

354

Naval weapons center active fault map series  

NASA Astrophysics Data System (ADS)

The NWC Active Fault Map Series shows the locations of active faults and features indicative of active faulting within much of Indian Wells Valley and portions of the Randsburg Wash/Mojave B test range areas of the Naval Weapons Center. Map annotations are used extensively to identify criteria employed in identifying the fault offsets, and to present other valuable data. All of the mapped faults show evidence of having moved during about the last 12,500 years or represent geologically young faults that occur within seismic gaps. Only faults that offset the surface or show other evidence of surface deformation were mapped. A portion of the City of Ridgecrest is recommended as being a Seismic Hazard Special Studies Zone in which detailed earthquake hazard studies should be required.

Roquemore, G. R.; Zellmer, J. T.

1987-08-01

355

Arc burst pattern analysis fault detection system  

NASA Technical Reports Server (NTRS)

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.

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

1997-01-01

356

Alp Transit: Crossing Faults 44 and 49  

NASA Astrophysics Data System (ADS)

This paper describes the crossing of faults 44 and 49 when constructing the 57 km Gotthard base tunnel of the Alp Transit project. Fault 44 is a permeable fault that triggered significant surface deformations 1,400 m above the tunnel when it was reached by the advancing excavation. The fault runs parallel to the downstream face of the Nalps arch dam. Significant deformations were measured at the dam crown. Fault 49 is sub-vertical and permeable, and runs parallel at the upstream face of the dam. It was necessary to assess the risk when crossing fault 49, as a limit was put on the acceptable dam deformation for structural safety. The simulation model, forecasts and action decided when crossing over the faults are presented, with a brief description of the tunnel, the dam, and the monitoring system.

El Tani, M.; Bremen, R.

2014-05-01

357

Basin width control of faulting in the Naryn Basin, south-central Kyrgyzstan  

NASA Astrophysics Data System (ADS)

In Central Asia's Tien Shan, deformation is distributed across the wide orogen, a characteristic of intracontinental mountain building. Active faults are commonly found within intramontane basins that separate its constituent ranges. In order to explore the controls on this intramontane basin deformation, we study the Naryn Basin of south-central Kyrgyzstan. A series of five balanced cross-sections reveals a transition in patterns of faulting from faults confined to basin margins to faults focused within the basin center. The 20-km-wide eastern Naryn Basin displays deformation attributed to low-angle splays of the northern, basin-bounding fault. In the 40-km-wide western Naryn Basin, the pattern of deformation linked to the northern range remains, but is accompanied by steeper faults that dip both south and north without being directly linked to the basin-bounding fault. We compare these cross-sections to synthetic aperture radar interferometry (InSAR) measurements of surface deformation. Profiles of InSAR-derived surface deformation rates across the Naryn Basin reveal that in the west, deformation is distributed across the broad basin interior, whereas in the east, rapid uplift is concentrated at the margin of the narrower basin. From the geodetic and structural data, we infer that in the western Naryn Basin, deformation has migrated away from the northern basin margin and into the interior. Deformation of the eastern basin interior, however, remains linked to the basin-bounding fault. A simple mechanical model demonstrates that basin width may control basin deformation whereby basin-interior faulting in the narrow, eastern Naryn Basin is inhibited by the overburden of adjacent ranges.

Goode, Joseph K.; Burbank, Douglas W.; Bookhagen, Bodo

2011-12-01

358

Paleoearthquake recurrence on the East Paradise fault zone, metropolitan Albuquerque, New Mexico  

USGS Publications Warehouse

A fortuitous exposure of the East Paradise fault zone near Arroyo de las Calabacillas has helped us determine a post-middle Pleistocene history for a long-forgotten Quaternary fault in the City of Albuquerque, New Mexico. Mapping of two exposures of the fault zone allowed us to measure a total vertical offset of 2.75 m across middle Pleistocene fluvial and eolian deposits and to estimate individual surface-faulting events of about 1, 0.5, and 1.25 m. These measurements and several thermoluminescence ages allow us to calculate a long-term average slip rate of 0.01 ± 0.001 mm/yr and date two surface-faulting events to 208 ± 25 ka and 75 ± 7 ka. The youngest event probably occurred in the late Pleistocene, sometime after 75 ± 7 ka. These data yield a single recurrence interval of 133 ± 26 ka and an average recurrence interval of 90 ± 10 ka. However, recurrence intervals are highly variable because the two youngest events occurred in less than 75 ka. Offsets of 0.5-1.25 m and a fault length of 13-20 km indicate that surface-rupturing paleoearthquakes on the East Paradise fault zone had probable Ms or Mw magnitudes of 6.8-7.0. Although recurrence intervals are long on the East Paradise fault zone, these data are significant because they represent some of the first published slip rate, paleoearthquake magnitude, and recurrence information for any of the numerous Quaternary faults in the rapidly growing Albuquerque-Rio Rancho metropolitan area.

Personius, Stephen F.; Mahan, Shannon A.

2000-01-01

359

Silica Lubrication in Faults (Invited)  

NASA Astrophysics Data System (ADS)

Silica-rich rocks are common in the crust, so silica lubrication may be important for causing fault weakening during earthquakes if the phenomenon occurs in nature. In laboratory friction experiments on chert, dramatic shear weakening has been attributed to amorphization and attraction of water from atmospheric humidity to form a 'silica gel'. Few observations of the slip surfaces have been reported, and the details of weakening mechanism(s) remain enigmatic. Therefore, no criteria exist on which to make comparisons of experimental materials to natural faults. We performed a series of friction experiments, characterized the materials formed on the sliding surface, and compared these to a geological fault in the same rock type. Experiments were performed in the presence of room humidity at 2.5 MPa normal stress with 3 and 30 m total displacement for a variety of slip rates (10-4 - 10-1 m/s). The friction coefficient (?) reduced from >0.6 to ~0.2 at 10-1 m/s, but only fell to ~0.4 at 10-2 - 10-4 m/s. The slip surfaces and wear material were observed using laser confocal Raman microscopy, electron microprobe, X-ray diffraction, and transmission electron microscopy. Experiments at 10-1 m/s formed wear material consisting of ?1 ?m powder that is aggregated into irregular 5-20 ?m clumps. Some material disaggregated during analysis with electron beams and lasers, suggesting hydrous and unstable components. Compressed powder forms smooth pavements on the surface in which grains are not visible (if present, they are <100 nm). Powder contains amorphous material and as yet unidentified crystalline and non-crystalline forms of silica (not quartz), while the worn chert surface underneath shows Raman spectra consistent with a mixture of quartz and amorphous material. If silica amorphization facilitates shear weakening in natural faults, similar wear materials should be formed, and we may be able to identify them through microstructural studies. However, the sub-micron particles of unstable materials are unlikely to survive in the crust over geologic time, so a direct comparison of fresh experimental wear material and ancient fault rock needs to account for the alteration and crystallization of primary materials. The surface of the Corona fault is coated by a translucent shiny layer consisting of ~100 nm interlocking groundmass of dislocation-free quartz, 10 nm ellipsoidal particles, and interstitial patches of amorphous silica. We interpret this layer as the equivalent of the experimentally produced amorphous material after crystallizing to more stable forms over geological time.

Rowe, C. D.; Rempe, M.; Lamothe, K.; Kirkpatrick, J. D.; White, J. C.; Mitchell, T. M.; Andrews, M.; Di Toro, G.

2013-12-01

360

BP network model optimized using the genetic algorithms and the application on fault diagnose of equipments  

Microsoft Academic Search

The BP nerve network has been widely applied on fault diagnosis. The BP network due to adopt search arithmetic along grads drop, therefore there are some problems such as slow convergence rate and easily getting into local infinitesimal. The genetic algorithms has the excellence of rapid searching rate. Therefore, auto-adapt genetic algorithms is adopted to optimize the BP algorithms in

Meng Xianyao; Han Xinjie; Meng Song

2006-01-01

361

Active tectonics of the Beichuan and Pengguan faults at the eastern margin of the Tibetan Plateau  

Microsoft Academic Search

The steep, high-relief eastern margin of the Tibetan Plateau has undergone rapid Cenozoic cooling and denudation yet shows little evidence for large-magnitude shortening or accommodation generation in the foreland basin. We address this paradox by using a variety of geomorphic observations to place constraints on the kinematics and slip rates of several large faults that parallel the plateau margin. The

Alexander L. Densmore; Michael A. Ellis; Yong Li; Rongjun Zhou; Gregory S. Hancock; Nicholas Richardson

2007-01-01

362

Development of a high current HVDC circuit breaker with fast fault clearing capability  

Microsoft Academic Search

Recent years have seen rapid growth in direct current transmission. This growth increases the need and scope of application for a high voltage direct current circuit breaker. Significant improvements have been made in a previously developed 500 kV, 2000A HVdc circuit breaker. These improvements have increased the current interrupting capabilities to 4000A dc and more and have decreased the fault

B. Pauli; G. Mauthe; E. Ruoss; G. Ecklin; J. Porter; J. Vithayathit

1988-01-01

363

The Work Budget of Rough Faults  

NASA Astrophysics Data System (ADS)

Faults in nature, while generally idealized as planar displacement discontinuities, are indeed rough and non-planar. This roughness is observable over many orders of magnitude across faults that may vary in length from tens of microns to several kilometers. Stress distributions along these rough fault profiles are highly heterogeneous, reflecting the fractal nature of the fault roughness. Here we utilize the boundary element method to model the work budget of frictional slip and opening on synthetic fault profiles generated with known fractal parameters, including the Hurst exponent and the root mean square slope, a measure of roughness amplitude. Energy within the fault models is partitioned into frictional, external, gravitational, seismic, and internal elastic strain energy. Results show that external work, or the work done on the external model boundaries, is smallest for a perfectly planar fault, and steadily increases with increasing roughness amplitude. This pattern is also seen in the internal strain energy, the energy expended in deforming the host rock. The opposite is true for gravitational work, or the work done against gravity in uplifting host rock, as well as with frictional work, the energy dissipated with frictional slip on the fault. These patterns correlate with the decrease in total slip, an increasing number of fault elements experiencing opening, and increasing roughness amplitude of faults. Remarkably, however, for a narrow range of roughness amplitudes which are commonly observed along natural faults, the total work of the system remains approximately constant, while slightly larger than the total work of a planar fault. Faults evolve toward the most mechanically efficient configuration; therefore we argue that this range of roughness amplitudes may act as an energy barrier, preventing faults from removing asperities and evolving to smooth, planar discontinuities.

Newman, P. J.; Griffith, W. A.; Cooke, M. L.

2012-12-01

364

Tracing the Geomorphic Signature of Lateral Faulting  

NASA Astrophysics Data System (ADS)

Active strike-slip faults are among the most dangerous geologic features on Earth. Unfortunately, it is challenging to estimate their slip rates, seismic hazard, and evolution over a range of timescales. An under-exploited tool in strike-slip fault characterization is quantitative analysis of the geomorphic response to lateral fault motion to extract tectonic information directly from the landscape. Past geomorphic work of this kind has focused almost exclusively on vertical motion, despite the ubiquity of horizontal motion in crustal deformation and mountain building. We seek to address this problem by investigating the landscape response to strike-slip faulting in two ways: 1) examining the geomorphology of the Marlborough Fault System (MFS), a suite of parallel strike-slip faults within the actively deforming South Island of New Zealand, and 2) conducting controlled experiments in strike-slip landscape evolution using the CHILD landscape evolution model. The MFS offers an excellent natural experiment site because fault initiation ages and cumulative displacements decrease from north to south, whereas slip rates increase over four fold across a region underlain by a single bedrock unit (Torlesse Greywacke). Comparison of planform and longitudinal profiles of rivers draining the MFS reveals strong disequilibrium within tributaries that drain to active fault strands, and suggests that river capture related to fault activity may be a regular process in strike-slip fault zones. Simple model experiments support this view. Model calculations that include horizontal motion as well as vertical uplift demonstrate river lengthening and shortening due to stream capture in response to shutter ridges sliding in front of stream outlets. These results suggest that systematic variability in fluvial knickpoint location, drainage area, and incision rates along different faults or fault segments may be expected in catchments upstream of strike-slip faults and could act as useful indicators of fault activity.

Duvall, A. R.; Tucker, G. E.

2012-12-01

365

Structural anisotropy of normal fault surfaces  

NASA Astrophysics Data System (ADS)

Precise description of natural fault surfaces is indispensable to understanding the geometry, mechanics and fluid transport properties of faults. Profiles of fault surfaces in the Wasatch fault zone and Oquirrh Mountains, Utah, are measured at 30° increments within the fault plane to determine the directional anisotropy of surface roughness at wavelengths between 10 -3 m and 30 m, and then compared with profiles of larger-scale fault surfaces. Surface anisotropy and an increasing ratio of surface amplitude to wavelength are consistent with self-affine fault topography at wavelengths between 1 mm and approximately 5 km. Fractal dimension of surface profiles generally decreases systematically as the angle to the slip direction increases. Directional anisotropy is described by an azimuthal scaling function ?? = K sin( ?) + ?0 or AF? = ( AFmax -1) sin( ?) + 1, where ?? and AF? are the amplitude to wavelength ratio and anisotropy factor respectively at azimuth ?, measured clockwise relative to slip direction within the fault surface, and ?0 is the amplitude to wavelength ratio parallel to slip direction. K = ( ?90 - ?0) is an anisotropy coefficient and increases systematically with spatial wavelength on the fault surface. Characterization of natural fault surfaces provides parameters such as fractal dimension ( D), intercept (log( C)) of power spectra, profile variance, and variation in anisotropy factor ( AF), which are needed to generate fractal models of natural fault surfaces using spectral synthesis. We generate sample models which illustrate the differences between fault surfaces characterized by constant versus azimuthally varying fractal dimension. The latter model surfaces contain low amplitude corrugations superimposed on elongate ridges which parallel slip direction. This surface texture resembles that of natural fault surfaces that refract across lithologic layering or are cut by secondary faults such as R and R' shears.

Lee, Joong-Jeek; Bruhn, Ronald L.

1996-08-01

366

Has the San Gabriel fault been offset  

SciTech Connect

The San Gabriel fault (SGF) in southern California is a right-lateral, strike-slip fault extending for 85 mi in an arcuate, southwestward-bowing curve from near the San Andreas fault at Frazier Mountain to its intersection with the left-lateral San Antonio Canyon fault (SACF) in the eastern San Gabriel Mountains. Termination of the SGF at the presently active SACF is abrupt and prompts the question Has the San Gabriel Fault been offset. Tectonic and geometric relationships in the area suggest that the SGF has been offset approximately 6 mi in a left-lateral sense and that the offset continuation of the SGF, across the SACF, is the right-lateral, strike-slip San Jacinto fault (SJF), which also terminates at the SACF. Reversing the left-lateral movement on the SACF to rejoin the offset ends of the SGF and SJF reveals a fault trace that is remarkably similar in geometry and movement (and perhaps in tectonic history), to the trace of the San Andreas fault through the southern part of the San Bernardino Mountains. The relationship of the Sierra Madre-Cucamonga fault system to the restored SGF-SJF fault is strikingly similar to the relationship of the Banning fault to the Mission Creek-Mill Creek portion of the San Andreas fault. Structural relations suggest that the San Gabriel-San Jacinto system predates the San Andreas fault in the eastern San Gabriel Mountains and that continuing movement on the SACF is currently affecting the trace of the San Andreas fault in the Cajon Pass area.

Sheehan, J.R.

1988-03-01

367

The Earthquake Loading Cycle and the Deep Structure of the North Anatolian Fault  

NASA Astrophysics Data System (ADS)

Deformation of the Earth's upper crust is localised onto narrow fault zones, which may slip suddenly and catastrophically in earthquakes. Strain in the upper mantle is more broadly distributed and is typically thought to occur by continuous ductile creep. The transition in the lower crust from broad shear zone to a narrow structure in the upper crust is poorly understood but the properties of the lower crust are an important control on the behaviour of the system during the earthquake loading cycle. The properties of lower crustal rocks, and their spatial variation, cannot be measured directly; instead inferences are typically made from seismic observations, exhumed geological analogues, and modelling of surface deformation data. Existing seismic experiments have poor resolution in the lower crust; and current geodetic models do not reproduce observations of rapid post-seismic and focussed inter-seismic strain. Here we present the preliminary findings of FaultLab, an interdisciplinary experiment using seismic imaging, geodesy, numerical modelling, and geology to investigate how the earthquake loading cycle of the North Anatolian Fault Zone is controlled by its deep crustal structure. We present results from an 18 month deployment of a 73 station network encompassing the northern and southern branches of the NAFZ in the Sakarya region. The dense array (nominal station station spacing of 7 km) crosses the 1999 Izmit earthquake rupture and is designed to provide high resolution images of the mid-lower crust. Teleseismic scattering tomography and receiver function analysis suggest that the two branches of the fault remain as relatively narrow structures to at least 20 km, and that the faults separate very different terranes. This portion of the North Anatolian Fault has the best geodetic record for any strike-slip fault, with deformation well recorded both before and after the 1999 earthquakes. Prior to the earthquake, strain was focused in a ~50 km region around the fault. Following the earthquake, a rapid post-seismic transient was observed, which slowly decayed over the subsequent decade. Viscoelastic modelling requires materials with at least two relaxation time constants to explain these observations - a strong material to allow focused interseismic strain, and a weak material to give rapid postseismic deformation. Geological analogues of the mid-lower crust beneath the North Anatolian Fault are consistent with the idea that strain is focused in relatively narrow shear zones. We present a shear-zone model for the earthquake deformation cycle that is consistent with these interdisciplinary observations, and discuss the implications for other fault zones.

Wright, Tim; Cornwell, David; Farrell, Katie; Houseman, Greg; Hussain, Ekbal; Llloyd, Geoffrey; Phillips, Richard; Thompson, David; Rost, Sebastian; Yamasaki, Tadashi; Turkelli, Niyazi; Gulen, Levent

2014-05-01

368

3D simulation of near-fault strong ground motion: comparison between surface rupture fault and buried fault  

NASA Astrophysics Data System (ADS)

In this paper, near-fault strong ground motions caused by a surface rupture fault (SRF) and a buried fault (BF) are numerically simulated and compared by using a time-space-decoupled, explicit finite element method combined with a multi-transmitting formula (MTF) of an artificial boundary. Prior to the comparison, verification of the explicit element method and the MTF is conducted. The comparison results show that the final dislocation of the SRF is larger than the BF for the same stress drop on the fault plane. The maximum final dislocation occurs on the fault upper line for the SRF; however, for the BF, the maximum final dislocation is located on the fault central part. Meanwhile, the PGA, PGV and PGD of long period ground motions (?1 Hz) generated by the SRF are much higher than those of the BF in the near-fault region. The peak value of the velocity pulse generated by the SRF is also higher than the BF. Furthermore, it is found that in a very narrow region along the fault trace, ground motions caused by the SRF are much higher than by the BF. These results may explain why SRFs almost always cause heavy damage in near-fault regions compared to buried faults.

Liu, Qifang; Yuan, Yifan; Jin, Xing

2007-12-01

369

Fault Diagnosis on Multiple Fault Models by Using Pass/Fail Information  

NASA Astrophysics Data System (ADS)

In general, we do not know which fault model can explain the cause of the faulty values at the primary outputs in a circuit under test before starting diagnosis. Moreover, under Built-In Self Test (BIST) environment, it is difficult to know which primary output has a faulty value on the application of a failing test pattern. In this paper, we propose an effective diagnosis method on multiple fault models, based on only pass/fail information on the applied test patterns. The proposed method deduces both the fault model and the fault location based on the number of detections for the single stuck-at fault at each line, by performing single stuck-at fault simulation with both passing and failing test patterns. To improve the ability of fault diagnosis, our method uses the logic values of lines and the condition whether the stuck-at faults at the lines are detected or not by passing and failing test patterns. Experimental results show that our method can accurately identify the fault models (stuck-at fault model, AND/OR bridging fault model, dominance bridging fault model, or open fault model) for 90% faulty circuits and that the faulty sites are located within two candidate faults.

Takamatsu, Yuzo; Takahashi, Hiroshi; Higami, Yoshinobu; Aikyo, Takashi; Yamazaki, Koji

370

Dynamic Modeling of Coseismic Rupture on Partially-Creeping Strike-Slip Faults  

NASA Astrophysics Data System (ADS)

Partially creeping faults exhibit complex behavior in terms of which parts of the fault slip seismically versus aseismically; this complexity is both temporal and spatial. Several faults in California exhibit creep that is rapid enough to be detected geodetically using InSAR, GPS and near-field methods, such as theodolite measurements of alignment arrays. Such studies of the Hayward Fault in the San Francisco Bay Area suggest that it has a complex pattern of creeping and locked patches along strike and down dip. The spatial pattern of creeping versus locked zones may have as much of an effect on throughgoing rupture as the more general presence of creep does. We use the 3D finite element modeling code FaultMod to conduct single-cycle models of dynamic rupture on partially creeping strike slip faults, in order to determine whether coseismic rupture can propagate into creeping regions, and how the presence and distribution of creep affects the ability of rupture to propagate along strike. We implement a rate-state friction criterion, in which locked zones of the fault are represented by rate-weakening behavior, and creeping zones of the fault are assigned rate-strengthening properties. We model two simplified partial creep geometries: a locked patch at the base of a largely creeping fault (similar to what is inferred for the Hayward Fault), and a creeping patch at the surface of a predominantly locked fault (similar to what is inferred for the Rodgers Creek Fault). We find that, in the case of a locked patch within a creeping fault, rupture does not propagate more than a kilometer past the edges of the locked patch, regardless of the patch radius. The case of a creeping patch within a locked fault is more complicated. We find that the width of the locked areas around the creeping patch determine whether or not rupture is able to propagate around the creeping patch and along the full strike of the fault; if the width of locked zone between the edge of the creeping patch and the end of the fault is too narrow, rupture is arrested. Regardless of along strike extent, rupture is able to penetrate several kilometers into the creeping patch, or all the way through it in the case of smaller patch radii, though at a slower rate than in the locked parts of the fault. By imposing multiple creeping and locked patches on a realistically complex fault geometry, we expect to be able to estimate the spatial and temporal distribution of coseismic slip on a partially creeping fault. We believe that combining the results of such dynamic models with static models of interseismic and postseismic creep may allow us to extend our slip estimates to cover the full earthquake cycle.

Lozos, J.; Funning, G.; Oglesby, D. D.

2013-12-01

371

Stacking faults in Si nanocrystals  

SciTech Connect

Si nanocrystals (Si nc) were formed by the implantation of Si{sup +} into a SiO{sub 2} film on (100) Si, followed by high-temperature annealing. High-resolution transmission electron microscopy has been used to examine the microstructure of the Si nc produced by a high-dose (3x10{sup 17} cm{sup -2}) implantation. It is shown that there are only stacking-fault (SF) defects in some nanocrystals; while in others the stacking faults (SFs) coexist with twins. Two kinds of SFs, one being an intrinsic SF, the other being an extrinsic SF, have been observed inside the Si nc. More intrinsic SFs have been found in the Si nc, and the possible reasons are discussed. These microstructural defects are expected to play an important role in the light emission from the Si nc.

Wang, Y.Q.; Smirani, R.; Ross, G.G. [INRS-EMT, 1650, Boulevard Lionel-Boulet, Varennes, Quebec, J3X 1S2 (Canada)

2005-05-30

372

Perspective View, San Andreas Fault  

NASA Technical Reports Server (NTRS)

The prominent linear feature straight down the center of this perspective view is California's famous San Andreas Fault. The image, created with data from NASA's Shuttle Radar Topography Mission (SRTM), will be used by geologists studying fault dynamics and landforms resulting from active tectonics. This segment of the fault lies west of the city of Palmdale, Calif., about 100 kilometers (about 60 miles) northwest of Los Angeles. The fault is the active tectonic boundary between the North American plate on the right, and the Pacific plate on the left. Relative to each other, the Pacific plate is moving away from the viewer and the North American plate is moving toward the viewer along what geologists call a right lateral strike-slip fault. Two large mountain ranges are visible, the San Gabriel Mountains on the left and the Tehachapi Mountains in the upper right. Another fault, the Garlock Fault lies at the base of the Tehachapis; the San Andreas and the Garlock Faults meet in the center distance near the town of Gorman. In the distance, over the Tehachapi Mountains is California's Central Valley. Along the foothills in the right hand part of the image is the Antelope Valley, including the Antelope Valley California Poppy Reserve. The data used to create this image were acquired by SRTM aboard the Space Shuttle Endeavour, launched on February 11, 2000.

This type of display adds the important dimension of elevation to the study of land use and environmental processes as observed in satellite images. The perspective view was created by draping a Landsat satellite image over an SRTM elevation model. Topography is exaggerated 1.5 times vertically. The Landsat image was provided by the United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota.

SRTM uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

Size: Varies in a perspective view Location: 34.70 deg. North lat., 118.57 deg. West lon. Orientation: Looking Northwest Original Data Resolution: SRTM and Landsat: 30 meters (99 feet) Date Acquired: February 16, 2000

2000-01-01

373

Fault trees and imperfect coverage  

NASA Technical Reports Server (NTRS)

A new algorithm is presented for solving the fault tree. The algorithm includes the dynamic behavior of the fault/error handling model but obviates the need for the Markov chain solution. As the state space is expanded in a breadth-first search (the same is done in the conversion to a Markov chain), the state's contribution to each future state is calculated exactly. A dynamic state truncation technique is also presented; it produces bounds on the unreliability of the system by considering only part of the state space. Since the model is solved as the state space is generated, the process can be stopped as soon as the desired accuracy is reached.

Dugan, Joanne B.

1989-01-01

374

Superconducting fault-current limiter  

NASA Astrophysics Data System (ADS)

The use of superconductivity to limit fault currents in power systems was examined. The various types of superconducting fault current limiters (SCFCL) were identified through a literature search, then analyzed and compared. The following design parameters were developed: 2.75 ohms, 118 kV (rms, 163 MJ for resistive limiters; 14.5 mH, 110 kV (rms), 8.3 MJ for inductive limiters. The operating characteristics of the resistive SCFCL were derived using transient circuit and heat transfer analysis. Evaluation of SCFCL performance and materials evaluation are discussed. Nb3Sn on a sapphire substrate appears to be the most promising material. No insurmountable obstacles to the development of an SCFCL were revealed. A substantial amount of detailed design and process development will be required before a fully rated module is built for power testing.

1982-02-01

375

RAPID TSUNAMI MODELS AND EARTHQUAKE SOURCE PARAMETERS: FAR-FIELD AND LOCAL APPLICATIONS  

Microsoft Academic Search

Rapid tsunami models have recently been developed to forecast far-field tsunami amplitudes from initial earthquake information (magnitude and hypocenter). Earthquake source parameters that directly affect tsunami generation as used in rapid tsunami models are examined, with particular attention to local versus far-field application of those models. First, validity of the assumption that the focal mechanism and type of faulting for

Eric L. Geist

376

Folding above faults, Rocky Mountains  

SciTech Connect

Asymmetric folds formed above basement faults can be observed throughout the Rocky Mountains. Several previous interpretations of the folding process made the implicit assumption that one or both fold hinges migrated or rolled'' through the steep forelimb of the fold as the structure evolved (rolling hinge model). Results of mapping in the Bighorn and Seminoe Mountains, WY, and Sangre de Cristo Range, CO, do not support this hypothesis. An alternative interpretation is presented in which fold hinges remained fixed in position during folding (fixed hinge model). Mapped folds share common characteristics: (1) axial traces of the folds intersect faults at or near the basement/cover interface, and diverge from faults upsection; (2) fold hinges are narrow and interlimb angles cluster around 80--100[degree] regardless of fold location; (3) fold shape is typically angular, despite published cross sections that show concentric folds; and, (4) beds within the folds show thickening and/or thinning, most commonly adjacent to fold hinges. The rolling hinge model requires that rocks in the fold forelimbs bend through narrow fold hinges as deformation progressed. Examination of massive, competent rock units such as the Ord. Bighorn Dolomite, Miss. Madison Limestone, and, Penn. Tensleep Sandstone reveals no evidence of the extensive internal deformation that would be expected if hinges rolled through rocks of the forelimb. The hinges of some folds (e.g. Golf Creek anticline, Bighorn Mountains) are offset by secondary faults, effectively preventing the passage of rocks from backlimb to forelimb. The fixed hinge model proposes that the fold hinges were defined early in fold evolution, and beds were progressively rotated and steepened as the structure grew.

McConnell, D.A. (Univ. of Akron, OH (United States). Dept. of Geology)

1992-01-01

377

Distributed multisensor fusion for machine condition monitoring fault diagnosis  

NASA Astrophysics Data System (ADS)

This paper presents a new general framework for multisensor fusion based on a distributed detection. Parallel processing and distributed multisensor fusion, as rapidly emerging and promising technologies, provides powerful tools for solving this difficult problem, The distribution and parallelism of proposing and confirming of hypothesis in condition and diagnostic is prosed. A combination serial and parallel reconfiguration of n sensors for decision fusion is analyzed. It shows the result for a real-time parallel distributed complex machine condition monitor and fault diagnostic system.

Wang, Xue; Zhao, Guohua; Xie, Xin

2001-09-01

378

Mantle convection with plates and mobile, faulted plate margins.  

PubMed

A finite-element formulation of faults has been incorporated into time-dependent models of mantle convection with realistic rheology, continents, and phase changes. Realistic tectonic plates naturally form with self-consistent coupling between plate and mantle dynamics. After the initiation of subduction, trenches rapidly roll back with subducted slabs temporarily laid out along the base of the transition zone. After the slabs have penetrated into the lower mantle, the velocity of trench migration decreases markedly. The inhibition of slab penetration into the lower mantle by the 670-kilometer phase change is greatly reduced in these models as compared to models without tectonic plates. PMID:17813909

Zhong, S; Gurnis, M

1995-02-10

379

DC superconducting fault current limiter  

NASA Astrophysics Data System (ADS)

There is a lack of satisfying solutions for fault currents using conventional technologies, especially in DC networks, where a superconducting fault current limiter could play a very important part. DC networks bring a lot of advantages when compared to traditional AC ones, in particular within the context of the liberalization of the electric market. Under normal operation in a DC network, the losses in the superconducting element are nearly zero and only a small, i.e. a low cost, refrigeration system is then required. The absence of zero crossing of a DC fault current favourably accelerates the normal zone propagation. The very high current slope at the time of the short circuit in a DC grid is another favourable parameter. The material used for the experiments is YBCO deposited on Al2O3 as well as YBCO coated conductors. The DC limitation experiments are compared to AC ones at different frequencies (50-2000 Hz). Careful attention is paid to the quench homogenization, which is one of the key issues for an SC FCL. The University of Geneva has proposed constrictions. We have investigated an operating temperature higher than 77 K. As for YBCO bulk, an operation closer to the critical temperature brings a highly improved homogeneity in the electric field development. The material can then absorb large energies without degradation. We present tests at various temperatures. These promising results are to be confirmed over long lengths.

Tixador, P.; Villard, C.; Cointe, Y.

2006-03-01

380

Oligocene Initiation of the Central Altyn Tagh Fault System Inferred From 40Ar/39Ar K-feldspar Thermochronology  

NASA Astrophysics Data System (ADS)

Determining the timing of Cenozoic deformation within and to the north of the Tibetan plateau is one of the major problems in understanding the evolution of the Indo-Asian collision. The NE-SW striking, left-slip Altyn Tagh fault system defines the northwestern margin of the Tibetan plateau and has played a key role in the collision by transferring deformation into the interior of Asia. Between 85° E and 92° E longitude the fault system is a 100 km wide shear zone that contains two main strands: the North Altyn fault in the north and the Altyn Tagh fault to the south. Structural mapping along the westernmost 120 km of the North Altyn fault indicates Tertiary motion was dominantly left-slip, with a small reverse component. To determine the ages of these two structures we have performed 40Ar/39Ar step heating experiments on fifteen basement K-feldspar samples collected between 85° 40'E and 86° 55'E longitude. Five of the samples are from tectonic slivers within 8 km of the active trace of the Altyn Tagh fault and show clear evidence of Oligocene to Early Miocene accelerated cooling. Eight samples from along the North Altyn fault show evidence of Late Triassic to Early Jurassic rapid cooling followed by a second phase of cooling in the middle Oligocene. We interpret the data from both the tectonic slivers along the Altyn Tagh fault and basement exposures along the North Altyn fault to indicate that slip along these structures had initiated by the Early Oligocene. Furthermore, we suggest that the left-slip North Altyn fault has reactivated a Mesozoic reverse fault. Mesozoic cooling of rocks along the North Altyn fault likely reflects denudation in the hanging wall of a NW-directed reverse fault since our structural mapping indicates Middle Jurassic fanglomerates in the footwall of the North Altyn fault experienced NW-directed contractional deformation prior to development of a Cretaceous(?) angular unconformity. Ongoing modeling of the 40Ar/39Ar data in the context of multidiffusion domain theory will allow us to place more precise constraints on the timing of Oligocene cooling, the age of the Altyn Tagh fault, and the magnitude of post-Jurassic vertical separation across the North Altyn fault.

Cowgill, E.; Yin, A.; Harrison, T. M.; Grove, M.; Wang, X.

2001-12-01

381

Clumped isotopes reveal the influence of deformation style on fluid flow and cementation along the Moab Fault, Paradox Basin, Utah  

NASA Astrophysics Data System (ADS)

Brittle fault systems can serve as either conduits or barriers to fluid flow, impacting mass and heat transfer in the crust and influencing the potential storage and migration of hydrocarbons and geothermal fluids. For fault systems in porous sandstones, different classes of structures control both hydrological and mechanical behavior during fault evolution: while cataclastic deformation bands form zones of localized deformation and crushed grains that reduce permeability within and across fault zones, joints can act as significant conduits for fluid. We investigate the relationship between structures and fluid flow in porous sandstones by studying calcite cements along the Moab Fault, a large normal fault system in the Paradox Basin, Utah. We use clumped isotope thermometry of fault cements to independently determine both the temperature and ?18O of the water from which the cements grew, placing new constraints on the source and path of diagenetic fluids in the basin. Based on fluid inclusion micro-thermometry and stable isotopic analysis of calcite cements from the Moab Fault, previous workers have hypothesized that joints served as conduits for the ascension of warm (84-125 °C) basinal fluids and deeply circulating meteoric waters. At the minor joint-dominated fault segment from which these data were collected, clumped isotope temperatures range from 57±10 to 101±2°C (2 SE), consistent with this hypothesis. However, at the nearby intersection of two major fault segments - in a zone characterized by both deformation bands and abundant joints - we find a broad range of temperatures (12±4 to 78±4°C) that vary spatially with distance from the fault and correlate with variations in secondary deformation structures (joints and deformation bands). These data provide the first evidence for cement growth from Earth surface-temperature fluids along the Moab Fault and suggests that the Fault served as a conduit for both ascending and descending fluids. The spatial distribution of low-temperature cements argues for rapid penetration of surface waters flowing down intensely-jointed fault intersections and suggests that deformation-band faults served as low-permeability baffles, preventing lateral migration of cold fluids. This interpretation is consistent with the cathodoluminescence patterns and ?18O and ?13C values of the samples, and confirms the important role of structures in transmission and compartmentalization of fluids in porous rocks. Our study illustrates how clumped isotope thermometry can aid in understanding interactions of mechanical, chemical, and transport processes associated with fractures and faults.

Huntington, K. W.; Bergman, S.; Crider, J. G.

2012-12-01

382

The evolution of fabric with displacement in natural brittle faults  

NASA Astrophysics Data System (ADS)

In experiments performed at room temperature on gouges, a characteristic clast size distribution (CSD) is produced with increasing strain, and shear localization is documented to begin after few millimetres of sliding. But in natural faults active at depth in the crust, mechanical processes are associated with fluid-rock interactions, which might control the deformation and strength recovery. We aim to investigate the microstructural, geochemical and mineralogical evolution of low-displacement faults with increasing shear strain. The faults (cataclasite- and pseudotachylyte-bearing) are hosted in tonalite and were active at 9-11 km and 250-300°C. The samples were collected on a large glacier-polished outcrop, where major faults (accommodating up to 4300 mm of displacement) exploit pre-existing magmatic joints and are connected by a network of secondary fractures and faults (accommodating up to 500 mm of displacement) breaking intact tonalite. We performed optical and cathodoluminescence (CL) microscope, Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Rietveld X-Ray Powder Diffraction and microprobe chemical analysis in deformation zones of secondary faults with various offsets in order to evaluate the transfer of chemical species between dissolution zones and protected zones. Image analysis techniques were applied on SEM-BSE and optical microscope images to compute the CSD in samples, which experienced an increasing amount of strain. The secondary fractures are up to 5 mm thick. Within the first 20 mm of displacement, shear localizes along Y and R1 surfaces and a cataclastic foliation develops. The CSD evolves from a fractal dimension D of 1.3 in fractures without visible displacement to values above 2 after the first 500 mm of displacement. Chemical maps and CL images indicate that the foliation in cataclasite results from the rotation and fragmentation of clasts, with dissolution of quartz and passive concentration of Ti oxides and titanite in the foliation planes. The cataclasites are cemented by pervasive precipitation of K-feldspar plagues and idiomorphic, randomly oriented, epidote and chlorite. We conclude that the textures of these small displacement (< 500 mm) faults are controlled by brittle processes (fracture propagation and cataclastic comminution) similar to those reproduced in friction experiments performed on granite gouge (e.g., Beeler et al., 1996; Logan, 2007). Then progressively, stress driven fluid-rock reactions develop as fracturing and grain size reduction allows the kinetics of these reactions to be more efficient and fracture interconnection allows fluid infiltration. Healing of microfractures and fault rock cementation caused a rapid posteismic recovery of fault strength. References Beeler, N.M., Tullis, T.E., Blanpied, L., Weeks, J.D., 1996. Frictional behaviour of large displacement experimental faults. Journal of Geophysical Research 101, B4, 8697-8715. Logan, J.M., 2007. The progression from damage to localization of displacement observed in laboratory testing of porous rocks, in Lewis, H., and Couples, G.D. (eds.) The relationship between damage and localization. Geological Society of London Special Publication 289, 75-87.

Mittempergher, S.; Di Toro, G.; Gratier, J.; Aretusini, S.; Boullier-Bertrand, A.

2011-12-01

383

Fault tolerant operation of switched reluctance machine  

NASA Astrophysics Data System (ADS)

The energy crisis and environmental challenges have driven industry towards more energy efficient solutions. With nearly 60% of electricity consumed by various electric machines in industry sector, advancement in the efficiency of the electric drive system is of vital importance. Adjustable speed drive system (ASDS) provides excellent speed regulation and dynamic performance as well as dramatically improved system efficiency compared with conventional motors without electronics drives. Industry has witnessed tremendous grow in ASDS applications not only as a driving force but also as an electric auxiliary system for replacing bulky and low efficiency auxiliary hydraulic and mechanical systems. With the vast penetration of ASDS, its fault tolerant operation capability is more widely recognized as an important feature of drive performance especially for aerospace, automotive applications and other industrial drive applications demanding high reliability. The Switched Reluctance Machine (SRM), a low cost, highly reliable electric machine with fault tolerant operation capability, has drawn substantial attention in the past three decades. Nevertheless, SRM is not free of fault. Certain faults such as converter faults, sensor faults, winding shorts, eccentricity and position sensor faults are commonly shared among all ASDS. In this dissertation, a thorough understanding of various faults and their influence on transient and steady state performance of SRM is developed via simulation and experimental study, providing necessary knowledge for fault detection and post fault management. Lumped parameter models are established for fast real time simulation and drive control. Based on the behavior of the faults, a fault detection scheme is developed for the purpose of fast and reliable fault diagnosis. In order to improve the SRM power and torque capacity under faults, the maximum torque per ampere excitation are conceptualized and validated through theoretical analysis and experiments. With the proposed optimal waveform, torque production is greatly improved under the same Root Mean Square (RMS) current constraint. Additionally, position sensorless operation methods under phase faults are investigated to account for the combination of physical position sensor and phase winding faults. A comprehensive solution for position sensorless operation under single and multiple phases fault are proposed and validated through experiments. Continuous position sensorless operation with seamless transition between various numbers of phase fault is achieved.

Wang, Wei

384

Constraints on the stress state of the San Andreas Fault with analysis based on core and cuttings from San Andreas Fault Observatory at Depth (SAFOD) drilling phases 1 and 2  

USGS Publications Warehouse

Analysis of field data has led different investigators to conclude that the San Andreas Fault (SAF) has either anomalously low frictional sliding strength (?? 0.6). Arguments for the apparent weakness of the SAF generally hinge on conceptual models involving intrinsically weak gouge or elevated pore pressure within the fault zone. Some models assert that weak gouge and/or high pore pressure exist under static conditions while others consider strength loss or fluid pressure increase due to rapid coseismic fault slip. The present paper is composed of three parts. First, we develop generalized equations, based on and consistent with the Rice (1992) fault zone model to relate stress orientation and magnitude to depth-dependent coefficient of friction and pore pressure. Second, we present temperature-and pressure-dependent friction measurements from wet illite-rich fault gouge extracted from San Andreas Fault Observatory at Depth (SAFOD) phase 1 core samples and from weak minerals associated with the San Andreas Fault. Third, we reevaluate the state of stress on the San Andreas Fault in light of new constraints imposed by SAFOD borehole data. Pure talc (?????0.1) had the lowest strength considered and was sufficiently weak to satisfy weak fault heat flow and stress orientation constraints with hydrostatic pore pressure. Other fault gouges showed a systematic increase in strength with increasing temperature and pressure. In this case, heat flow and stress orientation constraints would require elevated pore pressure and, in some cases, fault zone pore pressure in excess of vertical stress. Copyright 2009 by the American Geophysical Union.

Tembe, S.; Lockner, D.; Wong, T. -F.

2009-01-01

385

Fault plane processes and internal architecture of a "strong" paleoseismic fault  

NASA Astrophysics Data System (ADS)

Mature major faults are characterized by high values of displacement/fault thickness resulting by localized repeated slip along the same weakness horizon. A contrasting end-member is a fault where successive slip increments migrate to different discrete shear zone thus resulting in a fault zone with a low displacement/fault thickness ratio (strong fault?). An example of this second type of fault is studied in this work. The Gole Larghe-Val di Genova Fault (GGF) is an exhumed paleoseismic source crosscutting the whole northwestern Adamello batholith (Italian Southern Alps). Fault rocks are an association of indurated proto-ultracataclasites (PUC) and pseudotachylytes (PT). Seismic faulting occurred at 6-8km depth and 250-300^oC. In the studied zone, the GGF accommodates 900m of dextral strike slip displacement over a thickness of 550m. Within the fault displacement is localized into 3 hierarchically different sets of cataclastic horizons (rank 1-3 faults). Rank 1-2 faults nucleated on a pre-existing set of cooling joints. Rank 3 faults form a network of minor fractures newly produced during slip on rank 1-2 faults. Production of pseudotachylytes is usually the last event recorded by each of the GGF faults, and occurs at the host rock/cataclasite boundary. The matrix of PUC contains abundant K-feldspar+epidote+/-chlorite. PT and PUC have a similar chemical composition and are enriched in Loss On Ignition, K_2O, Rb, Ba, U and Fe_2O_3 compared to host rock. This indicates a strong fluid-rock interaction during fault deformation. Field data indicate that each rank 1-2 fault accommodates seismically a "significant" part of slip and, therefore, single faults within GGF were not contemporaneously active. Continuous migration of slip to new deformation horizons is related to the progressive induration of fault rocks during slip by precipitation of K-feldspar+epidote. The spatial evolution of cementation depends on the complex feedback between deformation, permeability and fluid-induced reactions. Progressive cementation enhanced localization within the fault, which finally led to seismic sliding and frictional melting. The production of PT welded the active fault and displacement migrated to nearby joints or less evolved faults of the GGF. The progressive induration and PT welding of the fault rock assemblage explains the bulk low displacement accommodation efficiency of the GGF.

di Toro, G.; Pennacchioni, G.

2003-04-01

386

Neotectonics of Panama. I. Major fault systems  

SciTech Connect

The direction and rate of relative plate motion across the Caribbean-Nazca boundary in Panama is poorly known. This lack of understanding can be attributed to diffuse seismicity; lack of well constrained focal mechanisms from critical areas; and dense tropical vegetation. In order to better understand the relation of plate motions to major fault systems in Panama, the authors have integrated geologic, remote sensing, earthquake and UTIG marine seismic reflection data. Three areas of recent faulting can be distinguished in Panama and its shelf areas; ZONE 1 of eastern Panama consists of a 70 km wide zone of 3 discrete left-lateral strike-slip faults (Sanson Hills, Jaque River, Sambu) which strike N40W and can be traced as continuous features for distances of 100-150 km; ZONE 2 in central Panama consists of a diffuse zone of discontinuous normal(.) faults which range in strike from N40E, N70E; ZONE 3 in western Panama consists of a 60 km wide zone of 2 discrete, left-lateral(.) strike-slip faults which strike N60W and can be traced as continuous features for distances of 150 km; ZONE 3 faults appear to be continuous with faults bounding the forearc Teraba Trough of Costa Rica. The relation of faults of ZONE 3 to faults of ZONE 2 and a major fault bounding the southern Panama shelf is unclear.

Corrigan, J.; Mann, P.

1985-01-01

387

Formation of stacking faults and the screw dislocation-driven growth: a case study of aluminum nitride nanowires.  

PubMed

Stacking faults are an important class of crystal defects commonly observed in nanostructures of close packed crystal structures. They can bridge the transition between hexagonal wurtzite (WZ) and cubic zinc blende (ZB) phases, with the most known example represented by the "nanowire (NW) twinning superlattice". Understanding the formation mechanisms of stacking faults is crucial to better control them and thus enhance the capability of tailoring physical properties of nanomaterials through defect engineering. Here we provide a different perspective to the formation of stacking faults associated with the screw dislocation-driven growth mechanism of nanomaterials. With the use of NWs of WZ aluminum nitride (AlN) grown by a high-temperature nitridation method as the model system, dislocation-driven growth was first confirmed by transmission electron microscopy (TEM). Meanwhile numerous stacking faults and associated partial dislocations were also observed and identified to be the Type I stacking faults and the Frank partial dislocations, respectively, using high-resolution TEM. In contrast, AlN NWs obtained by rapid quenching after growth displayed no stacking faults or partial dislocations; instead many of them had voids that were associated with the dislocation-driven growth. On the basis of these observations, we suggest a formation mechanism of stacking faults that originate from dislocation voids during the cooling process in the syntheses. Similar stacking fault features were also observed in other NWs with WZ structure, such as cadmium sulfide (CdS) and zinc oxide (ZnO). PMID:24295225

Meng, Fei; Estruga, Marc; Forticaux, Audrey; Morin, Stephen A; Wu, Qiang; Hu, Zheng; Jin, Song

2013-12-23

388

Fault imprint in clay units: magnetic fabric, structural and mineralogical signature  

NASA Astrophysics Data System (ADS)

Fault-induced deformations in clay units can be difficult to decipher because strain markers are not always visible at outcrop scale or using geophysical methods. Previous studies have indicated that the anisotropy of magnetic susceptibility (ASM) provides a powerful and rapid technique to investigate tectonic deformation in clay units even when they appear quite homogenous and undeformed at the outcrop scale (Lee et al. 1990, Mattei et al. 1997). We report here a study based on ASM, structural analysis and magnetic and clay mineralogy from two boreholes (TF1 and ASM1)drilled horizontally in the Experimental Station of Tournemire of the Institute for Radiological Protection and Nuclear Safety (IRSN) in Aveyron (France). The boreholes intersect a N-S trending strike-slip fault from west to east. The ASM study indicates the evolution of the magnetic fabric from the undeformed host rock to the fault core. Also, all the fractures cutting the studied interval of the core have been measured as well as the slip vectors which are generally well preserved. In the two boreholes, the undeformed sediments outside the fault zone are characterized by an oblate fabric, a sub-vertical minimum susceptibility axis (k3) perpendicular to the bedding plane and without magnetic lineation. Within the fault zone, a tilt in the bedding plane has been observed in two boreholes TF1 and ASM1. In addition, in the TF1 core, the fault area presents a tectonic fabric characterized by a triaxial AMS ellipsoid. Moreover, the magnetic lineation increases and k3 switches from a vertical to a sub-horizontal plane. This kind of fabric has not been observed in borehole ASM1. The structural analysis of the individual fractures making the fault zone indicates a complex tectonic history with different imprint in the two fault segments cut by the two boreholes. The large majority of fractures correspond to dextral strike-slip faults but normal and reverse movements were observed and are more or less frequent depending on the borehole. Notably, many fractures are low angle faults (dip<45°) and may bear both strike-slip or normal striae. The mineralogical study based on X-ray diffraction analysis, have pointed out some variations in clay minerals associations nearby the deformed zones that may be the result of fluid circulation along the fault system which is in agreement with the presence of goethite determined by low magnetic temperature measurements. This multi-proxi study, combining ASM, petrostructural and mineralogical approaches has highlighted the heterogeneity of the fault, but also its past role as a drain to fluid circulation.

Moreno, Eva; Homberg, Catherine; Schnyder, Johann; Person, Alain; du Peloux1, Arthur; Dick, Pierre

2014-05-01

389

Perspective View, San Andreas Fault  

NASA Technical Reports Server (NTRS)

The prominent linear feature straight down the center of this perspective view is the San Andreas Fault in an image created with data from NASA's shuttle Radar Topography Mission (SRTM), which will be used by geologists studying fault dynamics and landforms resulting from active tectonics. This segment of the fault lies west of the city of Palmdale, California, about 100 kilometers (about 60 miles) northwest of Los Angeles. The fault is the active tectonic boundary between the North American plate on the right, and the Pacific plate on the left. Relative to each other, the Pacific plate is moving away from the viewer and the North American plate is moving toward the viewer along what geologists call a right lateral strike-slip fault. This area is at the junction of two large mountain ranges, the San Gabriel Mountains on the left and the Tehachapi Mountains on the right. Quail Lake Reservoir sits in the topographic depression created by past movement along the fault. Interstate 5 is the prominent linear feature starting at the left edge of the image and continuing into the fault zone, passing eventually over Tejon Pass into the Central Valley, visible at the upper left.

This type of display adds the important dimension of elevation to the study of land use and environmental processes as observed in satellite images. The perspective view was created by draping a Landsat satellite image over an SRTM elevation model. Topography is exaggerated 1.5 times vertically. The Landsat image was provided by the United States Geological Survey's Earth Resources Observations Systems (EROS) Data Center, Sioux Falls, South Dakota.

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise,Washington, DC.

Size: Varies in a perspective view Location: 34.78 deg. North lat., 118.75 deg. West lon. Orientation: Looking Northwest Original Data Resolution: SRTM and Landsat: 30 meters (99 feet) Date Acquired: February 16, 2000

2000-01-01

390

Paleomagnetic Data From the Rinconada Fault in Central California: Evidence for Off-fault Deformation  

NASA Astrophysics Data System (ADS)

The Rinconada fault is one of three major sub-parallel faults of the San Andreas fault system in central California. The fault has 18 km of dextral displacement since the Pliocene and up to 60 km of total displacement for the Tertiary. A fold and thrust best is well developed in Miocene and younger sedimentary rocks on either side of the Rinconada fault. We sampled ~150 sites from the Miocene Monterey Formation within this fold and thrust belt, a unit that is often used in regional paleomagnetic studies. The sites were located within 15 km of the fault trace along a segment of the Rinconada fault that stretches from Greenfield to Paso Robles. Because this unit was deposited while the San Andreas fault system was active at this latitude, any deformation recorded by these rocks is related to plate boundary deformation. Unlike the large (>90°) rotations observed in the Transverse Ranges to the south, vertical axis rotations adjacent to the Rinconada fault are smaller (<15°) and vary with distance from the fault as well as along strike. Thus, the model for rotations from the Transverse Ranges, where large fault-bound panels rotate within a system of conjugate strike-slip faults, does not apply for this region in central California. Instead, we believe rotations occur in small fault blocks and the magnitude of rotation may be affected by local parameters such as fault geometries, specific rock types, and structural complexities. One implication of these vertical axis rotations adjacent to the Riconada fault is that off-fault regions are accommodating some of the fault-parallel plate motion. This is important for our understanding of the partitioning of plate boundary deformation in California.

Crump, S.; Titus, S.; McGuire, Z.; Housen, B. A.

2009-12-01

391

Primary and secondary faulting in the Najd fault system, Kingdom of Saudi Arabia  

USGS Publications Warehouse

The Najd fault system is a major transcurrent (strike-slip) fault system of Proterozoic age in the Arabian Shield. The system is a braided complex of parallel and curved en echelon faults. Complex arrays of secondary structures including strike-slip, oblique-slip, thrust, and normal faults, together with folds and dike swarms, are associated with some major faults, particularly near their terminations. The secondary structures indicate that compressional and extensional and dilational conditions existed synchronously in different parts of the fault zone. The outcrop traces of faults and syntectonic dikes have been used to interpret the configuration of principal compressive stresses during formation of parts of the secondary fracture systems. Second-order deformation was a series of separate events in a complex episodic faulting history. Comparison with model studies indicates that master faults extended in length in stages and periodically developed arrays of secondary structures. Propagation of the major faults took place along splay trajectories, which inter-connected to form a subparallel sheeted and braided zone. Interpretation of the aeromagnetic maps indicates that the Najd system is broader at depth than the outcropping fault complex, and that more continuous structures underlie arrays of faults at surface. The fault pattern is mechanically explicable in terms of simple shear between rigid blocks beneath the exposed structures.

Moore, John McMahon

1979-01-01

392

California Fault Zone Orphan Borehole Database  

NASA Astrophysics Data System (ADS)

California is tectonically active and has many abandoned boreholes across the state. With information on these boreholes provided by the Division of Oil, Gas, and Geothermal Resources (DOGGR), we have been able to create several interactive maps on Google Earth for a public website and database accessible at: http://www.pmc.ucsc.edu/~rapid/ . These maps locate abandoned and adoptable wells near active quaternary fault traces and are linked to relevant subsurface information. The links on the website include complete histories, logs, lithologies, stratigraphic columns, and casing information (when available). Earthquake scientists may utilize these wells for monitoring subsurface changes prior, during, and after an earthquake in California. The boreholes could be used for the measurements of several subsurface observables, including: repeat temperature logs, stress measurements, geophysical logging, repeat active-source seismic experiments, sampling of mud/ gas/ fluids, long-term monitoring of temperature and pore fluid pressure, passive seismicity, etc. The “Adopt a Well Program” with DOGGR allows the orphaned well to be tested for 90 days without liability then purchased upon approval. With the science of seismology expanding its limits, these boreholes offer the depth necessary to have accurate subsurface data in order to make informed implications about what occurs deep beneath the surface.

Avila, J.; Brodsky, E. E.

2009-12-01

393

Networking of Near Fault Observatories in Europe  

NASA Astrophysics Data System (ADS)

Networking of six European near-fault observatories (NFO) was established In the FP7 infrastructure project NERA (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation). This networking has included sharing of expertise and know-how among the observatories, distribution of analysis tools and access to data. The focus of the NFOs is on research into the active processes of their respective fault zones through acquisition and analysis of multidisciplinary data. These studies include the role of fluids in fault initiation, site effects, derived processes such as earthquake generated tsunamis and landslides, mapping the internal structure of fault systems and development of automatic early warning systems. The six fault zones are in different tectonic regimes: The South Iceland Seismic Zone (SISZ) in Iceland, the Marmara Sea in Turkey and the Corinth Rift in Greece are at plate boundaries, with strike-slip faulting characterizing the SISZ and the Marmara Sea, while normal faulting dominates in the Corinth Rift. The Alto Tiberina and Irpinia faults, dominated by low- and medium-angle normal faulting, respectively are in the Apennine mountain range in Italy and the Valais Region, characterized by both strike-slip and normal faulting is located in the Swiss Alps. The fault structures range from well-developed long faults, such as in the Marmara Sea, to more complex networks of smaller, book-shelf faults such as in the SISZ. Earthquake hazard in the fault zones ranges from significant to substantial. The Marmara Sea and Corinth rift are under ocean causing additional tsunami hazard and steep slopes and sediment-filled valleys in the Valais give rise to hazards from landslides and liquefaction. Induced seismicity has repeatedly occurred in connection with geothermal drilling and water injection in the SISZ and active volcanoes flanking the SISZ also give rise to volcanic hazard due to volcano-tectonic interaction. Organization among the NERA NFO's has led to their gaining working-group status in EPOS as the WG on Near Fault Observatories, representing multidisciplinary research of faults and fault zones.

Vogfjörd, Kristín; Bernard, Pascal; Chiraluce, Lauro; Fäh, Donat; Festa, Gaetano; Zulficar, Can

2014-05-01

394

Rapid Deployment UAV  

Microsoft Academic Search

Besides UCAV, present winged or helicopter-style UAVs waste too much time and fuel to takeoff and arrive an unpredicted trouble spot. This study presents two design concepts of rapid deployment UAV: the first is vertical launch surface-based rapid deployment UAV (RDUAV), and the second is air-launched rapid deployment UAV (AL-RDUAV). The proposed rapid deployment UAVs should rapidly reach the destination

Shun-Wen Cheng

2008-01-01

395

POTENTIAL EFFECTS OF FAULTS ON GROUNDWATER FLOW FOR THE YUCCA FLAT BASIN, NEVADA TEST SITE, NEVADA  

Microsoft Academic Search

The permeability changes resulting from finely comminuted material in fault cores and the fractured and brecciated rock in fault damage zones allows faults to channelize groundwater flow along the plane of the fault. The efficiency of faults as permeability structures depends on fault zone width, fault offset, depth at which the fault developed, type of faulted rock, extent of secondary

R. P. Dickerson; W. Fryer

2009-01-01

396

The aftermath of silurian faulting in southeast Michigan, and its effect on oil and gas exploration  

SciTech Connect

In Macomb Township of Macomb County, southeast Michigan, is found a sinuous normal fault extending along a N82[degrees]W strike, from end to end only 6 mi long, but with more than 260 ft of maximum displacement at the Trenton level. Through about 3 mi of its midsection extent, the main fault is paired with another normal fault with opposite displacement sense, forming a very narrow graben. The timing of development of this divergent wrench feature coincides with Caledonian tectonic activity, a period of intense structural disturbance and regional subsidence throughout the Michigan basin. The fault appears to cut no higher than A[sub 1] Carbonate, although relationships are obscured by subsequent dissolution of more than 500 ft of Salina A[sub 1], A[sub 2], B, D, and F salts along and beyond the trace of the fault. Collapse of interbedded carbonates and shales is evident, although the apparent lack of brecciation indicates salt removal was not rapid. Further, salt removal proceeded throughout the Devonian, producing dramatic compensatory thickening in overlying units. The development of this large feature in prime Niagaran reef territory may have prevented the discovery of reefs by obscuring what is otherwise well-known stratigraphy and seismic signature. The presence of oil production in dolomitized fracture zones in the Trenton/Black River rocks of nearby Ontario may point to similar potential yet remaining along the Macomb faulted trend.

Fowler, J.H. (Polaris Energy, Jackson, MI (United States))

1994-08-01

397

Sensor and Sensorless Fault Tolerant Control for Induction Motors Using a Wavelet Index  

PubMed Central

Fault Tolerant Control (FTC) systems are crucial in industry to ensure safe and reliable operation, especially of motor drives. This paper proposes the use of multiple controllers for a FTC system of an induction motor drive, selected based on a switching mechanism. The system switches between sensor vector control, sensorless vector control, closed-loop voltage by frequency (V/f) control and open loop V/f control. Vector control offers high performance, while V/f is a simple, low cost strategy with high speed and satisfactory performance. The faults dealt with are speed sensor failures, stator winding open circuits, shorts and minimum voltage faults. In the event of compound faults, a protection unit halts motor operation. The faults are detected using a wavelet index. For the sensorless vector control, a novel Boosted Model Reference Adaptive System (BMRAS) to estimate the motor speed is presented, which reduces tuning time. Both simulation results and experimental results with an induction motor drive show the scheme to be a fast and effective one for fault detection, while the control methods transition smoothly and ensure the effectiveness of the FTC system. The system is also shown to be flexible, reverting rapidly back to the dominant controller if the motor returns to a healthy state.

Gaeid, Khalaf Salloum; Ping, Hew Wooi; Khalid, Mustafa; Masaoud, Ammar

2012-01-01

398

Could lithospheric instability cause the San Andreas Fault to creep ?  

NASA Astrophysics Data System (ADS)

The Southern Sierra Nevada mountains range rapidly uplifted at ? 3.5 Ma simultaneously with a pulse of basaltic volcanism. Xenoliths recovered from volcanics indicate that the range lost a dense crustal root after the Miocene. The vertical motions and removal of the root have been linked to a fast seismic velocity anomaly that extends ? 200 km into the mantle but is offset to the west of the range. With visco-elasto-plastic thermo-mechanical numerical models, we have tested the influence of crustal strength on the kinematics of removal and on the amount of associated uplift. We find that delamination of the dense root is the most likely mechanism for gravitational instability to occur. In this class of models, the Great Valley deforms by elastic flexure in response to the load exerted by the delaminated root. We therefore explore the influence of the strength of the Great Valley on the wavelength of the flexure and complement 2D models by flexural 3D models. The study shows that for a Te=10 km, the flexural anomaly resulting from the drip pull outlines the limit between the area where the Quaternary sediments are found on-lapping or off-lapping the western flank of the Sierra. On the Western edge of the Sierra Nevada micro plate, the flexural anomaly crosses the San