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Sample records for active-source seismic monitoring

  1. Recent Results from Crosswell CASSM (Continuous Active-Source Seismic Monitoring)

    NASA Astrophysics Data System (ADS)

    Daley, T. M.; Ajo Franklin, J. B.; Niu, F.

    2011-12-01

    The precision in-situ measurement of seismic properties has been previously demonstrated by crosswell CASSM surveys utilizing piezoelectric seismic sources and various seismic sensors. The underlying precision of travel time measurement (and hence velocity measurement) is shown to be a function of signal-to-noise ratio (S/N), and therefore the semi-permanent CASSM deployment allows massive stacking to provide very large S/N. With high precision data, properties such as the velocity-stress dependence can be resolved. In this presentation, data from three recent CASSM deployments will be shown. First, we will present the recent measurement of stress dependence at 1 km depth in the San Andreas Fault Observatory at Depth (SAFOD). This work follows on the published observation of preseismic stress changes (Niu, et al, 2008) with a redeployment of instrumentation at SAFOD. The latest SAFOD deployment, in which we collected ~40-days of data, from February 19, 2010 to March 31, 2010, suffered from instrumentation failure before observation of seismicity, but data for velocity-stress calibration was acquired using barometric pressure, and the stress sensitivity result of ~2.5 x 10-7 Pa-1 is in agreement with our previous measurement. Secondly, we show a measurement of effective stress dependence in a 3 km deep reservoir used for CO2 sequestration in Cranfield, MS. This experiment uses a fluid pump test, with downhole pressure gauge, to demonstrate a velocity-stress sensitivity of ~5 x 10-6 MPa-1 . In the third CASSM experiment, the methodology was expanded to multi-level measurement (ML-CASSM) of hydrofracture growth in a shallow (~30 m) bioremediation project. In this experiment we demonstrate the first fully automated multi-source/multi-sensor CASSM system capable of tomographic velocity imaging with temporal resolution of 3-4 minutes. This temporal sampling allowed quantitative imaging of velocity changing in response to fracture growth.

  2. Active source monitoring of crosswell seismic travel time forstress induced changes

    SciTech Connect

    Silver, P.G.; Daley, T.M.; Niu, F.; Majer, E.L.

    2006-11-11

    We have conducted a series of cross-well experiments tocontinuously measure in situ temporal variations in seismic velocity attwo test sites: building 64 (B64) and Richmond Field Station (RFS) of theLawrence Berkeley National Laboratory in California. A piezoelectricsource was used to generate highly repeatable signals, and a string of 24hydrophones was used to record the signals. The B64 experiment wasconducted utilizing two boreholes 17 m deep and 3 m apart for 160 h. AtRFS, we collected a 36-day continuous record in a cross-borehole facilityusing two 70-m-deep holes separated by 30 m. With signal enhancementtechniques we were able to achieve a precision of 6.0 nsec and 10 nsec indelay-time estimation from stacking of 1-hr records during the ?7- and?35-day observation periods at the B64 and RFS sites, which correspond to3 and 0.5 ppm of their travel times, respectively. Delay time measured atB64 has a variation of ?2 lsec in the 160-hr period and shows a strongand positive correlation with the barometric pressure change at the site.At RFS, after removal of a linear trend, we find a delay-time variationof 2.5 lsec, which exhibits a significant negative correlation withbarometric pressure. We attribute the observed correlations to stresssensitivity of seismic velocity known from laboratory studies. Thepositive and negative sign observed in the correlation is likely relatedto the expected near- and far-field effects of this stress dependence ina poroelastic medium. The stress sensitivity is estimated to be 10 6/Paand 10 7/Pa at the B64 and RFS site, respectively.

  3. Active Source Seismic Experiment Peers Under Soufrière Hills Volcano

    NASA Astrophysics Data System (ADS)

    Voight, Barry; Sparks, R. S. J.; Hammond, J.; Shalev, E.; Malin, P.; Kenedi, C.; Minshull, T. A.; Paulatto, M.; Mattioli, G.; Hidayat, D.; Widiwijayanti, C.

    2010-07-01

    Characterizing internal structures of active volcanoes remains an enigmatic issue in geosciences. Yet studies of such structures can greatly improve hazard assessments, helping scientists to better monitor seismic signatures, geodetic deformation, and gas emissions, data that can be used to improve models and forecasts of future eruptions. Several passive seismic tomography experiments—which use travel times of seismic waves from natural earthquakes to image underground structures—have been conducted at active volcanoes (Hawaii's Kilauea, Washington's Mount St. Helens, Italy's Etna, and Japan's Unzen), but an inhomogeneous distribution of earthquakes compromises resolution. Further, if volcanic earthquakes are dominantly shallow at a given location, passive methods are limited to studying only shallow features. Thus, active source experiments—where seismic waves from the explosion of deliberately set charges are used to image below the surface—hold great potential to illuminate structures not readily seen through passive measures.

  4. Seismic Imaging and Monitoring

    SciTech Connect

    Huang, Lianjie

    2012-07-09

    I give an overview of LANL's capability in seismic imaging and monitoring. I present some seismic imaging and monitoring results, including imaging of complex structures, subsalt imaging of Gulf of Mexico, fault/fracture zone imaging for geothermal exploration at the Jemez pueblo, time-lapse imaging of a walkway vertical seismic profiling data for monitoring CO{sub 2} inject at SACROC, and microseismic event locations for monitoring CO{sub 2} injection at Aneth. These examples demonstrate LANL's high-resolution and high-fidelity seismic imaging and monitoring capabilities.

  5. Seismic exploration of Fuji volcano with active sources in 2003

    NASA Astrophysics Data System (ADS)

    Oikawa, J.; Kagiyama, T.; Tanaka, S.; Miyamachi, H.; Tsutsui, T.; Ikeda, Y.; Katayama, H.; Matsuo, N.; Oshima, H.; Nishimura, Y.; Yamamoto, K.; Watanabe, T.; Yamazaki, F.

    2004-12-01

    Fuji volcano (altitude 3,776 m) is the largest basaltic stratovolcano in Japan. In late August and early September 2003, seismic exploration was conducted around Fuji volcano by the detonation of 500 kg charges of dynamite to investigate the seismic structure of that area. Seismographs with an eigenfrequency of 2 Hz were used for observation, positioned along a WSW-ENE line passing through the summit of the mountain. A total of 469 observation points were installed at intervals of 250-500 m. The data were stored in memory on-site using data loggers. The sampling interval was 4 ms. Charges were detonated at 5 points, one at each end of the observation line and 3 along its length. The first arrival times at each observation point for each detonation were recorded as data. The P-wave velocity structure directly below the observation line was determined by forward calculation using the ray tracing method [Zelt and Smith, 1992]. The P-wave velocity structure below the volcano, assuming a layered structure, was found to be as follows. (1) The first layer extends for about 40 km around the summit and to a depth of 1-2 km. The P-wave velocity is 2.5 km/s on the upper surface of the layer and 3.5 km/s on the lower interface. (2) The second layer has P-wave velocities of 4.0 km/s on the top interface and 5.5 km/s at the lower interface. The layer is 25 km thick to the west of the summit and 1-2 km thick to the east, and forms a dome shape with a peak altitude of 2000 m directly below the summit. (3) The third layer is 5-12 km thick and has P-wave velocities of 5.7 km/s at the top interface and 6.5 km/s at the lower interface. This layer reaches shallower levels to the east of the summit, corresponding to the area where the second layer is thinner. Mt. Fuji is located slightly back from where the Philippine Sea Plate subducts below the Eurasian plate in association with collision with the Izu Peninsula. Matsuda (1971) suggested that Mt. Fuji lies on the same uplifted body as

  6. Induced Seismicity Monitoring System

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.; Jarpe, S.; Harben, P.

    2014-12-01

    There are many seismological aspects associated with monitoring of permanent storage of carbon dioxide (CO2) in geologic formations. Many of these include monitoring underground gas migration through detailed tomographic studies of rock properties, integrity of the cap rock and micro seismicity with time. These types of studies require expensive deployments of surface and borehole sensors in the vicinity of the CO2 injection wells. Another problem that may exist in CO2 sequestration fields is the potential for damaging induced seismicity associated with fluid injection into the geologic reservoir. Seismic hazard monitoring in CO2 sequestration fields requires a seismic network over a spatially larger region possibly having stations in remote settings. Expensive observatory-grade seismic systems are not necessary for seismic hazard deployments or small-scale tomographic studies. Hazard monitoring requires accurate location of induced seismicity to magnitude levels only slightly less than that which can be felt at the surface (e.g. magnitude 1), and the frequencies of interest for tomographic analysis are ~1 Hz and greater. We have developed a seismo/acoustic smart sensor system that can achieve the goals necessary for induced seismicity monitoring in CO2 sequestration fields. The unit is inexpensive, lightweight, easy to deploy, can operate remotely under harsh conditions and features 9 channels of recording (currently 3C 4.5 Hz geophone, MEMS accelerometer and microphone). An on-board processor allows for satellite transmission of parameter data to a processing center. Continuous or event-detected data is kept on two removable flash SD cards of up to 64+ Gbytes each. If available, data can be transmitted via cell phone modem or picked up via site visits. Low-power consumption allows for autonomous operation using only a 10 watt solar panel and a gel-cell battery. The system has been successfully tested for long-term (> 6 months) remote operations over a wide range

  7. Preliminary Results from the iMUSH Active Source Seismic Experiment

    NASA Astrophysics Data System (ADS)

    Levander, Alan; Kiser, Eric; Palomeras, Imma; Zelt, Colin; Schmandt, Brandon; Hansen, Steve; Harder, Steven; Creagar, Kenneth; Vidale, John; Abers, Geoffrey

    2015-04-01

    iMUSH (imaging Magma Under Saint Helens) is a US NSF sponsored multi-disciplinary investigation of Mount Saint Helens (MSH), currently the most active volcano in the Cascades arc in the northwestern United States. The project consists of active and passive seismic experiments, extensive magnetotelluric sounding, and geological/geochemical studies involving scientists at 7 institutions in the U.S. and Europe. The long-term goal of the seismic project is to combine analysis of the active source data with that of data from the 70 element broadband seismograph operating from summer 2014 until 2016. Combining seismic and MT analyses with other data, we hope to image the MSH volcanic plumbing system from the surface to the subducting Juan de Fuca slab. Here we describe preliminary results of the iMUSH active source seismic experiment, conducted in July and August 2014. The active source experiment consisted of twenty-three 454 or 908 kg weight shots recorded by ~3500 seismographs deployed at ~6,000 locations. Of these instruments, ~900 Nodal Seismic instruments were deployed continuously for two weeks in an areal array within 10 km of the MSH summit. 2,500 PASSCAL Texan instruments were deployed twice for five days in 3 areal arrays and 2 dense orthogonal linear arrays that extended from MSH to distances > 80 km. Overall the data quality from the shots is excellent. The seismograph arrays also recorded dozens of micro-earthquakes beneath the MSH summit and along the MSH seismic zone, and numerous other local and regional earthquakes. In addition, at least one low frequency event beneath MSH was recorded during the experiment. At this point we have begun various types of analysis of the data set: We have determined an average 1D Vp structure from stacking short-term/long-term average ratios, we have determined the 2-D Vp structure from ray-trace inversions along the two orthogonal profiles (in the NW-SE and NE-SW directions), and we have made low-fold CMP stacks of the

  8. Seismic monitoring of geomorphic processes

    NASA Astrophysics Data System (ADS)

    Burtin, A.; Hovius, N.; Turowski, J. M.

    2014-12-01

    In seismology, the signal is usually analysed for earthquake data, but these represent less than 1% of continuous recording. The remaining data are considered as seismic noise and were for a long time ignored. Over the past decades, the analysis of seismic noise has constantly increased in popularity, and this has led to develop new approaches and applications in geophysics. The study of continuous seismic records is now open to other disciplines, like geomorphology. The motion of mass at the Earth's surface generates seismic waves that are recorded by nearby seismometers and can be used to monitor its transfer through the landscape. Surface processes vary in nature, mechanism, magnitude and space and time, and this variability can be observed in the seismic signals. This contribution aims to give an overview of the development and current opportunities for the seismic monitoring of geomorphic processes. We first describe the common principles of seismic signal monitoring and introduce time-frequency analysis for the purpose of identification and differentiation of surface processes. Second, we present techniques to detect, locate and quantify geomorphic events. Third, we review the diverse layout of seismic arrays and highlight their advantages and limitations for specific processes, like slope or channel activity. Finally, we illustrate all these characteristics with the analysis of seismic data acquired in a small debris-flow catchment where geomorphic events show interactions and feedbacks. Further developments must aim to fully understand the richness of the continuous seismic signals, to better quantify the geomorphic activity and improve the performance of warning systems. Seismic monitoring may ultimately allow the continuous survey of erosion and transfer of sediments in the landscape on the scales of external forcing.

  9. Overview and early highlights of the TAIGER project marine, active-source seismic program (Invited)

    NASA Astrophysics Data System (ADS)

    McIntosh, K. D.; van Avendonk, H. J.; Liu, C.; Hsu, S.; Lee, C.; Wang, T. K.; Wu, F. T.

    2009-12-01

    The marine active-source portion of the TAIGER (TAIwan GEodynamic Research) project took place during April-July 2009 using the R/V Marcus Langseth with support from a variety of Taiwanese ships used to deploy and recover ocean bottom seismographs (OBSs). Due to Taiwanese shiptime (Langseth) contribution, the active-source program was doubled from our original proposal. Over the course of three, ~month-long cruises, the Langseth produced seismic source points along >13,000 km of track line. This includes > 11,000 km of deep-penetration multichannel seismic reflection data (MCS), shots to ~269 OBS stations (Taiwanese and U.S.), and shots to ~280 temporary land seismic stations across Taiwan. During this comprehensive project the Langseth circled Taiwan and ventured far to the south and east. TAIGER data cover the passive margin SW of Taiwan to provide a “pre-collision” structural configuration of the subducting plate, while TAIGER MCS and OBS data acquired on transects south of Taiwan will provide an idea of the “pre-collision” structural configuration of the Manila trench subduction zone. We will compare these areas to the evolving crustal structure of the Taiwan collision, which will be analyzed with onshore/offshore seismic data recorded during TAIGER legs 1 and 2. These TAIGER crustal transects will elucidate crucial components and stages of the southwestward advancing collision. We were able to process all the MCS data during the acquisition cruises to preliminary stack and FK migration. In much of the area SW of Taiwan we observe deep reflections, likely marking Moho. Surprisingly, even at distances > 250 km south of the shelf edge, apparent basement crustal thickness is frequently 3+ s (two-way travel time) or about 9-11 km. We also obtained exciting results across both the Manila/Luzon and Ryukyu arc-trench systems. These subduction systems are primarily characterized by ample sediment supply and relatively fast convergence leading to young, rapidly

  10. Active source monitoring at the Wenchuan fault zone: coseismic velocity change associated with aftershock event and its implication

    NASA Astrophysics Data System (ADS)

    Yang, Wei; Ge, Hongkui; Wang, Baoshan; Hu, Jiupeng; Yuan, Songyong; Qiao, Sen

    2014-12-01

    With the improvement of seismic observation system, more and more observations indicate that earthquakes may cause seismic velocity change. However, the amplitude and spatial distribution of the velocity variation remains a controversial issue. Recent active source monitoring carried out adjacent to Wenchuan Fault Scientific Drilling (WFSD) revealed unambiguous coseismic velocity change associated with a local M s5.5 earthquake. Here, we carry out forward modeling using two-dimensional spectral element method to further investigate the amplitude and spatial distribution of observed velocity change. The model is well constrained by results from seismic reflection and WFSD coring. Our model strongly suggests that the observed coseismic velocity change is localized within the fault zone with width of ~120 m rather than dynamic strong ground shaking. And a velocity decrease of ~2.0 % within the fault zone is required to fit the observed travel time delay distribution, which coincides with rock mechanical experiment and theoretical modeling.

  11. Field Report on the iMUSH Active Source Seismic Experiment

    NASA Astrophysics Data System (ADS)

    Kiser, E.; Levander, A.; Schmandt, B.; Palomeras, I.; Harder, S. H.; Creager, K. C.; Vidale, J. E.; Malone, S. D.

    2014-12-01

    In the second half of July we completed the iMUSH active source seismic experiment, one component of the Imaging Magma Under Saint Helens project. A team of ~75 volunteers deployed 3500 seismographs to ~5920 locations on and around Mount St. Helens over the course of 3 weeks. This instrument deployment was accompanied by 23 shots distributed around the volcano. Instrumentation consisted of ~2550 Reftek 125A (Texan) seismographs with 4.5 Hz geophones, and 920 Nodal Seismic recorders with 10 Hz geophones. The shots were also recorded by the permanent stations of the Pacific Northwest Seismograph Network and 70 iMUSH broadband seismographs. Fifteen of the shots, 424 kg each, formed two rings around Mount Saint Helens at 15 km and 30 km radius from the summit. Eight of the shots, 828 kg each, were fired at distances of 50 to 80 km from MSH on NW-SE and NE-SW azimuths. The deployment geometry consisted of two lines oriented NW/SE and NE/SW, and three arrays. The offset of the lines ranged from 150 km to 190 km with an average spacing of 200 m. The first array was centered on the volcano with a radius of 30 km, and required both driving and hiking to deploy. Arrays two and three were set out with, and centered on, the NW/SE line. These arrays had a distance range from MSH of 30-75 km and an azimuth range of about 100 degrees. In addition to this large-scale deployment, we set out 7 beamforming arrays approximately collocated with iMUSH broadband seismographs, and above clusters of seismicity in the region. The aperture of these arrays was about 1 km with an instrument spacing of 100 m. The final deployment ended only days before the AGU abstract deadline, so we have not yet examined all of the data. However, the preliminary indications are that signal to noise is excellent: The shots, several of which registered on PNSN as ML>2.1, carried across the entire array, and were recorded as far away as Seattle and Corvallis on permanent stations. The array also recorded a

  12. Crustal Thickness Variations Along the Southeastern Caribbean Plate Boundary From Teleseismic and Active Source Seismic Data

    NASA Astrophysics Data System (ADS)

    Bezada, M. J.; Niu, F.; Baldwin, T. K.; Pavlis, G.; Vernon, F.; Rendón, H.; Zelt, C. A.; Schmitz, M.; Levander, A.

    2006-12-01

    Insight into the topography of the Moho discontinuity beneath Venezuela has been progressively gained since the 1990's through seismic refraction studies carried out in the south and east of the country. More recently, both active and passive, land and marine seismic data were acquired by the U.S. BOLIVAR and Venezuelan GEODINOS projects to understand accretion processes and mechanisms for continental growth. The passive component includes an 18-month deployment of 27 PASSCAL broadband seismographs, a 12-month deployment of 15 OBSIP broadband instruments and an ongoing deployment of 8 Rice broadband seismometers. Additionally, data from the 34 BB stations of the national seismic network of Venezuela and the GSN SDV station, give a seismic dataset from 84 stations covering an area of ~750,000 km2. The active component includes 4 onshore-offshore refraction/wide angle reflection profiles as well as the recording of airgun blasts from offshore seismic lines by BB stations in mainland Venezuela and the Leeward Antilles. This abundance of datasets allows us to estimate Moho depths using different methods such as receiver functions, and forward and inverse modeling of wide-angle datasets, but also poses the challenge of reconciling the different values obtained to achieve robust results. Generally the active source and receiver function estimates are close to one another. We present a composite crustal thickness map showing a highly variable crustal thicknesses ranging from 15 km beneath the Caribbean LIP, to ~55 km beneath eastern Venezuela. Crustal thickness is strongly correlated with geologic terranes, but not always as expected. The thickest crust is found to exist in the east of the country, beneath the sedimentary basins north of the Orinoco River where depth to Moho exceeds 50 km. Crustal thickness beneath most of the Precambrian Guayana Shield is fairly constant at ~38 km . In contrast, we observe relatively thin (~25-30 km) crust in the eastern and western

  13. Pacific Upper Mantle Seismic Anisotropy from the Active-Source Seismic Component of the NoMelt Experiment

    NASA Astrophysics Data System (ADS)

    Mark, H. F.; Lizarralde, D.; Gaherty, J. B.; Collins, J. A.; Hirth, G.; Evans, R. L.

    2014-12-01

    We will present a measurement of azimuthal seismic anisotropy of Pacific-plate upper mantle based on Pn travel times from the active-source seismic component of the NoMelt experiment. The NoMelt experiment was conducted in 2012 on ~70-m.y.-old lithosphere, in the center of the spreading segment between the Clarion and Clipperton fracture zones, with the goal of delineating the detailed seismic and electrical structure of "normal," mature oceanic lithosphere. The seismic component of the experiment consisted of a 600x400 km array of 27 broad-band (BB) ocean bottom seismometers (OBS); 31 short period (SP) OBS, spaced at 20 km, deployed along the long axis of the array (the main transect), oriented along a plate-kinematic flow line; and 3 SP OBS deployed along a line normal to the main transect, at 50 km spacing, extending to 200 km southeast of the center of the main transect. The SP OBS array was deployed to record airgun shots fired by the R/V M.G. Langseth's 36-element array. Airgun shots were fired along the two perpendicular lines and also along a semi-circular arc with a 75-km radius centered at the line intersection at the center of the main transect. Pn (upper mantle refraction) arrivals from shots fired along the semicircle and recorded by OBS within the semicircle's arc span 180 degrees of azimuth and an offset range of ~40-150 km. Preliminary analyses of these Pn arrival travel times indicate an azimuthal dependence of P-wave speeds, which range from ~8.6 km/s to ~7.6 km/s. These preliminary results suggest a pattern of azimuthal wave-speed dependence that requires depth-dependent seismic anisotropy and/or a dipping mantle fabric, with the latter being more likely given the limited range of source/receiver offsets spanned by the Pn arrivals used in this analysis. We will present results that include these observations as well as Pn arrivals from a much more comprehensive set of source/receiver pairs from the NoMelt experiment.

  14. Seismic monitoring at The Geysers

    SciTech Connect

    Majer, E.L.; Romero, A.; Vasco, D.; Kirkpatrick, A.; Peterson, J.E.; Zucca, J.J.; Hutchings, L.J.; Kasameyer, P.W.

    1993-04-01

    During the last several years Lawrence Berkeley Laboratory (LBL) and Lawrence Livermore National Laboratory (LLNL) have been working with industry partners at The Geysers geothermal field to evaluate and develop methods for applying the results of microearthquake (MEQ) monitoring. It is a well know fact that seismicity at The Geysers is a common occurrence, however, there have been many studies and papers written on the origin and significance of the seismicity. The attitude toward MEQ data ranges from being nothing more than an curious artifact of the production activities, to being a critical tool in evaluating the reservoir performance. The purpose of the work undertaken b y LBL and LLNL is to evaluate the utility, as well as the methods and procedures used in of MEQ monitoring, recommend the most cost effective implementation of the methods, and if possible link physical processes and parameters to the generation of MEQ activity. To address the objectives above the MEQ work can be categorized into two types of studies. The first type is the direct analysis of the spatial and temporal distribution of MEQ activity and studying the nature of the source function relative to the physical or chemical processes causing the seismicity. The second broad area of study is imaging the reservoir/geothermal areas with the energy created by the MEQ activity and inferring the physical and/or chemical properties within the zone of imaging. The two types of studies have obvious overlap, and for a complete evaluation and development require high quality data from arrays of multicomponent stations. Much of the effort to date at The Geysers by both DOE and the producers has concentrated establishing a high quality data base. It is only within the last several years that this data base is being fully evaluated for the proper and cost effective use of MEQ activity. Presented here are the results to date of DOE`s effort in the acquisition and analysis of the MEQ data.

  15. Active-source seismic imaging below Lake Malawi (Nyasa) from the SEGMeNT project

    NASA Astrophysics Data System (ADS)

    Shillington, D. J.; Scholz, C. A.; Gaherty, J. B.; Accardo, N. J.; McCartney, T.; Chindandali, P. R. N.; Kamihanda, G.; Trinhammer, P.; Wood, D. A.; Khalfan, M.; Ebinger, C. J.; Nyblade, A.; Mbogoni, G. J.; Mruma, A. H.; Salima, J.; Ferdinand-Wambura, R.

    2015-12-01

    Little is known about the controls on the initiation and development of magmatism and segmentation in young rift systems. The northern Lake Malawi (Nyasa) rift in the East African Rift System is an early stage rift exhibiting pronounced tectonic segmentation, which is defined in the upper crust by ~100-km-long border faults. Very little volcanism is associated with rifting; the only surface expression of magmatism occurs in an accommodation zone between segments to the north of the lake in the Rungwe Volcanic Province. The SEGMeNT (Study of Extension and maGmatism in Malawi aNd Tanzania) project is a multidisciplinary, multinational study that is acquiring a suite of geophysical, geological and geochemical data to characterize deformation and magmatism in the crust and mantle lithosphere along 2-3 segments of this rift. As a part of the SEGMeNT project, we acquired seismic reflection and refraction data in Lake Malawi (Nyasa) in March-April 2015. Over 2000 km of seismic reflection data were acquired with a 500 to 2580 cu in air gun array from GEUS/Aarhus and a 500- to 1500-m-long seismic streamer from Syracuse University over a grid of lines across and along the northern and central basins. Air gun shots from MCS profiles and 1000 km of additional shooting with large shot intervals were also recorded on 27 short-period and 6 broadband lake bottom seismometers from Scripps Oceanographic Institute as a part of the Ocean Bottom Seismic Instrument Pool (OBSIP) as well as the 55-station onshore seismic array. The OBS were deployed along one long strike line and two dip lines. We will present preliminary data and results from seismic reflection and refraction data acquired in the lake and their implications for crustal deformation within and between rift segments. Seismic reflection data image structures up to ~5-6 km below the lake bottom, including syntectonic sediments, intrabasinal faults and other complex horsts. Some intrabasinal faults in both the northern and

  16. Preseismic velocity changes observed from active source monitoring at the Parkfield SAFOD drill site.

    PubMed

    Niu, Fenglin; Silver, Paul G; Daley, Thomas M; Cheng, Xin; Majer, Ernest L

    2008-07-10

    Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. One approach is to exploit the stress dependence of seismic wave velocity, and we have investigated this in an active source cross-well experiment at the San Andreas Fault Observatory at Depth (SAFOD) drill site. Here we show that stress changes are indeed measurable using this technique. Over a two-month period, we observed an excellent anti-correlation between changes in the time required for a shear wave to travel through the rock along a fixed pathway (a few microseconds) and variations in barometric pressure. We also observed two large excursions in the travel-time data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. The two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies.

  17. Active Source Tomography of Stromboli Volcano (Italy): Results From the 2006 Seismic Experiment.

    NASA Astrophysics Data System (ADS)

    Zuccarello, L.; Patanè, D.; Cocina, O.; Castellano, M.; Sgroi, T.; Favali, P.; de Gori, P.

    2008-12-01

    Stromboli island, located in the Southern Tyrrhenian sea, is the emerged part (about 900 m a.s.l.) of a 3km-high strato-volcano. Its persistent Strombolian activity, documented for over 2000 years, is sometimes interrupted by lava effusions or major explosions. Despite the amount of recent published geophysical studies aimed to clarifying eruption dynamics, the spatial extend and geometrical characteristics of the plumbing system remain poorly understood. In fact, the knowledge of the inner structure and the zones of magma storage is limited to the upper few hundreds meters of the volcanic edifice and P- and S-waves velocity models are available only in restricted areas. In order to obtain a more suitable internal structural and velocity models of the volcano, from 25 November to 2 December 2006, a seismic tomography experiment through active seismics using air-gun sources was carried out and the final Vp model is here presented. The data has been inverted for the Vp structure by using the code Simulps13q, considering a 3D grid of nodes spaced 0.5 km down to 2 km depth, beneath the central part of volcano. The results show a relatively high velocity zones located both in the inner part of the volcanic structure, at about 1km b.s.l. and in the last 200-300 m a.s.l. in correspondence with the volcanic conduit. Slower zones were located around the summit craters in agreement with volcanological and petrological informations for the area. The relatively high velocity zones could suggest the presence of intrusive bodies related to the plumbing system.

  18. Seismic monitoring of torrential and fluvial processes

    NASA Astrophysics Data System (ADS)

    Burtin, Arnaud; Hovius, Niels; Turowski, Jens M.

    2016-04-01

    In seismology, the signal is usually analysed for earthquake data, but earthquakes represent less than 1 % of continuous recording. The remaining data are considered as seismic noise and were for a long time ignored. Over the past decades, the analysis of seismic noise has constantly increased in popularity, and this has led to the development of new approaches and applications in geophysics. The study of continuous seismic records is now open to other disciplines, like geomorphology. The motion of mass at the Earth's surface generates seismic waves that are recorded by nearby seismometers and can be used to monitor mass transfer throughout the landscape. Surface processes vary in nature, mechanism, magnitude, space and time, and this variability can be observed in the seismic signals. This contribution gives an overview of the development and current opportunities for the seismic monitoring of geomorphic processes. We first describe the common principles of seismic signal monitoring and introduce time-frequency analysis for the purpose of identification and differentiation of surface processes. Second, we present techniques to detect, locate and quantify geomorphic events. Third, we review the diverse layout of seismic arrays and highlight their advantages and limitations for specific processes, like slope or channel activity. Finally, we illustrate all these characteristics with the analysis of seismic data acquired in a small debris-flow catchment where geomorphic events show interactions and feedbacks. Further developments must aim to fully understand the richness of the continuous seismic signals, to better quantify the geomorphic activity and to improve the performance of warning systems. Seismic monitoring may ultimately allow the continuous survey of erosion and transfer of sediments in the landscape on the scales of external forcing.

  19. Quarterly seismic monitoring report 96B

    SciTech Connect

    Reidel, S.P.

    1996-06-12

    This report summarizes the location, magnitude, and other pertinent information on earthquakes recorded on and near the Hanford Site by Westinghouse Seismic Monitoring during the period encompassing January 1, 1996 to March 31, 1996.

  20. Structure of the deep oceanic lithosphere in the Northwestern Pacific ocean basin derived from active-source seismic data

    NASA Astrophysics Data System (ADS)

    Ohira, A.; Kodaira, S.; Nakamura, Y.; Fujie, G.; Arai, R.; Miura, S.

    2015-12-01

    Many seismological studies have detected the sharp seismic discontinuities in the upper mantle, some of which are interpreted the lithosphere-asthenosphere boundary (LAB). However there are few data at the old Pacific plate, in particular at ocean basin, which is critical information for understanding nature of the oceanic LAB. In 2014 we conducted an active-source refraction/reflection survey along a 1130-km-long line in southeast of the Shatsky Rise. Five ocean bottom seismometers (OBSs) were deployed and recovered by R/V Kairei of JAMSTEC. We used an airgun array with a total volume of 7,800 cubic inches with firing at intervals of 200 m. Multi-channel seismic reflection (MCS) data were also collected with a 444-channel, 6,000-m-long streamer cable. In OBS records the apparent velocity of the refraction waves from the uppermost mantle was high (< 8.6 km/sec), and considered to be caused by preferred orientation of olivine (e.g., Kodaira et al., 2014). Another remarkable feature is wide-angle reflection waves from the deep lithosphere at large (150-500 km) offsets. We applied the traveltime mapping method (Fujie et al., 2006), forward analysis (Zelt and Smith, 1992) and the amplitude modeling (Larsen and Grieger, 1998) to the OBS data. The results show that deep mantle reflectors exist at the depths from 35 to 60 km, and one possible explanation is that these reflectors correspond to patched low velocity zones around the base of the lithosphere. On MCS sections the clear and sharp Moho was imaged only at the southwestern end of the profile, but Moho was ambiguous or even not imaged in the most part of the profile. Since our seismic line covers the oceanic lithosphere with different ages that correspond to different stages of the Shatsky activity, the Moho appearance may reflect the variation of the Shatsky activity.

  1. The application of active-source seismic imaging techniques to transtensional problems the Walker Lane and Salton Trough

    NASA Astrophysics Data System (ADS)

    Kell, Anna Marie

    The plate margin in the western United States is an active tectonic region that contains the integrated deformation between the North American and Pacific plates. Nearly focused plate motion between the North American and Pacific plates within the northern Gulf of California gives way north of the Salton Trough to more diffuse deformation. In particular a large fraction of the slip along the southernmost San Andreas fault ultimately bleeds eastward, including about 20% of the total plate motion budget that finds its way through the transtensional Walker Lane Deformation Belt just east of the Sierra Nevada mountain range. Fault-bounded ranges combined with intervening low-lying basins characterize this region; the down-dropped features are often filled with water, which present opportunities for seismic imaging at unprecedented scales. Here I present active-source seismic imaging from the Salton Sea and Walker Lane Deformation Belt, including both marine applications in lakes and shallow seas, and more conventional land-based techniques along the Carson range front. The complex fault network beneath the Salton Trough in eastern California is the on-land continuation of the Gulf of California rift system, where North American-Pacific plate motion is accommodated by a series of long transform faults, separated by small pull-apart, transtensional basins; the right-lateral San Andreas fault bounds this system to the north where it carries, on average, about 50% of total plate motion. The Salton Sea resides within the most youthful and northerly "spreading center" in this several thousand-kilometer-long rift system. The Sea provides an ideal environment for the use of high-data-density marine seismic techniques. Two active-source seismic campaigns in 2010 and 2011 show progression of the development of the Salton pull-apart sub-basin and the northerly propagation of the Imperial-San Andreas system through time at varying resolutions. High fidelity seismic imagery

  2. Shallow sediment and upper crustal structure beneath the Salton Sea as imaged by active source marine seismic refraction in conjunction with the Salton Seismic Imaging Project

    NASA Astrophysics Data System (ADS)

    Kell, A. M.; Sahakian, V. J.; Harding, A. J.; Kent, G.; Driscoll, N. W.

    2012-12-01

    In the spring of 2011 we expanded a campaign of marine seismic reflection efforts in the Salton Sea in conjunction with the Salton Seismic Imaging Project (SSIP) to collect active-source marine refraction data using Ocean Bottom Seismometers (OBSs) and a marine airgun. The Salton Trough presents an opportunity to study rifting processes similar to those seen in the Gulf of California, as well as the seismic hazards associated with the southern terminus of the San Andreas Fault (SAF). An areal array, comprised of 78 OBS deployments, was focused in the southern part of the sea but also included a line parallel to the San Andreas Fault (SAF) , line 1, extending then length of the sea, and a line perpendicular to the SAF, crossing the northern basin, line 7. These lines are collinear with high-resolution reflection profiles and existing chirp profiles. The OBS array was concentrated in the southern Salton Sea to investigate the pull-apart deformation reported by Brothers et al. (2009). Using the methods of Van Avendonk (2004) we seek to constrain upper crustal velocities in this region by travel-time tomography. Beginning with P-wave arrival times we trace the ray paths through the model space and invert for seismic velocities. By iterating from the forward picking to the inversion, we reduce the chi-squared error to produce a 2D depth profile of the seismic velocities while maintaining a stable model. Line 1 uses 38 OBSs and 470 shots from a 210 cu. in. airgun to model the upper 4 km beneath the Salton Sea. Velocities vary from 1.5 km/s in the upper 1 km to an apparent 4 km deep basement velocity of 5.5 km/s. Velocity variations with depth agree with major boundaries in the co-linear seismic reflection profiles and the divergence toward the south/fault structure is also captured in these early models. Preliminary results for line 7 show similarly varying velocities - 1.5 to 3 km/s in the upper 2 kilometers of the crust, to slightly over 4 km/s at 4 km depth. Further

  3. Forearc oceanic crust in the Izu-Bonin arc - new insights from active-source seismic survey -

    NASA Astrophysics Data System (ADS)

    Kodaira, S.; Noguchi, N.; Takahashi, N.; Ishizuka, O.; Kaneda, Y.

    2009-12-01

    Petrological studies have suggested that oceanic crust is formed in forearc areas during the initial stage of subduction. However, there is little geophysical evidence for the formation of oceanic crust in those regions. In order to examine crustal formation process associated with a subduction initiation process, we conducted an active-source seismic survey at a forearc region in the Izu-Bonin intra-oceanic arc. The resultant seismic image shows a remarkably thin crust (less than 10 km) at the northern half of the Bonin ridge (at the north of the Chichi-jima) and abrupt thickening the crust (~ 20 km thick) toward the south (at the Haha-jima). Comparison of velocity-depth profiles of the thin forearc crust of the Bonin ridge with those of typical oceanic crusts showed them to be seismologically identical. The observed structural variation also well corresponds to magmatic activities along the forearc. Boninitic magmatism is evident in the area of thin crust and tholeiitic-calcalkaline andesitic volcanism in the area of thick crust. Based on high precision dating studies of those volcanic rocks, we interpreted that the oceanic-type thin crust associated with boninitic volcanism has been created soon after the initiation of subduction (45-48 Ma) and and that the nonoceanic thick crust was created by tholeiitic-calcalkaline andesitic magmatism after the boninitic magmatism was ceased. The above seismological evidences strongly support the idea of forearc oceanic crust (or phiolite) created by forearc spreading in the initial stage of subduction along the intra-oceanic arc.

  4. Crustal Structure Across the Okavango Rift Zone, Botswana: Initial Results From the PRIDE-SEISORZ Active-Source Seismic Profile

    NASA Astrophysics Data System (ADS)

    Canales, J. P.; Moffat, L.; Lizarralde, D.; Laletsang, K.; Harder, S. H.; Kaip, G.; Modisi, M.

    2015-12-01

    The PRIDE project aims to understand the processes of continental rift initiation and evolution by analyzing along-axis trends in the southern portion of the East Africa Rift System, from Botswana through Zambia and Malawi. The SEISORZ active-source seismic component of PRIDE focused on the Okavango Rift Zone (ORZ) in northwestern Botswana, with the main goal of imaging the crustal structure across the ORZ. This will allow us to estimate total crustal extension, determine the pattern and amount of thinning, assess the possible presence of melt within the rift zone, and assess the contrasts in crustal blocks across the rift, which closely follows the trend of a fold belt. In November 2014 we conducted a crustal-scale, 450-km-long seismic refraction/wide-angle reflection profile consisting of 19 sources (shots in 30-m-deep boreholes) spaced ~25 km apart from each other, and 900 receivers (IRIS/PASSCAL "Texan" dataloggers and 4.5Hz geophones) with ~500 m spacing. From NW to SE, the profile crosses several tectonic domains: the Congo craton, the Damara metamorphic belt and the Ghanzi-Chobe fold belt where the axis of the ORZ is located, and continues into the Kalahari craton. The record sections display clear crustal refraction (Pg) and wide-angle Moho reflection (PmP) phases for all 17 of the good-quality shots, and a mantle refraction arrival (Pn), with the Pg-PmP-Pn triplication appearing at 175 km offset. There are distinct changes in the traveltime and amplitude of these phases along the transect, and on either side of the axis, that seem to correlate with sharp transitions across tectonic terrains. Initial modeling suggests: (1) the presence of a sedimentary half-graben structure at the rift axis beneath the Okavango delta, bounded to the SE by the Kunyere-Thamalakane fault system; (2) faster crustal Vp in the domains to the NW of the ORZ; and (3) thicker crust (45-50 km) at both ends of the profile within the Congo and Kalahari craton domains than at the ORZ and

  5. Seismic monitoring of the Yucca Mountain facility

    SciTech Connect

    Garbin, H.D.; Herrington, P.B.; Kromer, R.P.

    1997-08-01

    Questions have arisen regarding the applicability of seismic sensors to detect mining (re-entry) with a tunnel boring machine (TBM). Unlike cut and blast techniques of mining which produce impulsive seismic signals, the TBM produces seismic signals which are of long duration. (There are well established techniques available for detecting and locating the sources of the impulsive signals.) The Yucca Mountain repository offered an opportunity to perform field evaluations of the capabilities of seismic sensors because during much of 1996, mining there was progressing with the use of a TBM. During the mining of the repository`s southern branch, an effort was designed to evaluate whether the TBM could be detected, identified and located using seismic sensors. Three data acquisition stations were established in the Yucca Mountain area to monitor the TBM activity. A ratio of short term average to long term average algorithm was developed for use in signal detection based on the characteristics shown in the time series. For location of the source of detected signals, FK analysis was used on the array data to estimate back azimuths. The back azimuth from the 3 component system was estimated from the horizontal components. Unique features in the timing of the seismic signal were used to identify the source as the TBM.

  6. Downhole Seismic Monitoring at the Geysers

    SciTech Connect

    Rutledge, J.T.; Anderson, T.D.; Fairbanks, T.D.; Albright, J.N.

    1999-10-17

    A 500-ft length, 6-level, 3-component, vertical geophone array was permanently deployed within the upper 800 ft of Unocal's well GDCF 63-29 during a plug and abandonment operation on April 7, 1998. The downhole array remains operational after a period of 1 year, at a temperature of about 150 C. Continuous monitoring and analysis of shallow seismicity (<4000 ft deep) has been conducted over that same 1-year period. The downhole array was supplemented with 4 surface stations in late-1998 and early-1999 to help constrain locations of shallow seismicity. Locations occurring within about 1 km ({approximately}3000 ft) of the array have been determined for a subset of high-frequency events detected on the downhole and surface stations for the 10-week period January 6 to March 16, 1999. These events are distinct from surface-monitored seismicity at The Geysers in that they occur predominantly above the producing reservoir, at depths ranging from about 1200 to 4000 ft depth (1450 to -1350 ft elevation). The shallow seismicity shows a northeast striking trend, similar to seismicity trends mapped deeper within the reservoir and the strike of the predominant surface lineament observed over the productive field.

  7. Monitoring hydraulic fracturing with seismic emission volume

    NASA Astrophysics Data System (ADS)

    Niu, F.; Tang, Y.; Chen, H.; TAO, K.; Levander, A.

    2014-12-01

    Recent developments in horizontal drilling and hydraulic fracturing have made it possible to access the reservoirs that are not available for massive production in the past. Hydraulic fracturing is designed to enhance rock permeability and reservoir drainage through the creation of fracture networks. Microseismic monitoring has been proven to be an effective and valuable technology to image hydraulic fracture geometry. Based on data acquisition, seismic monitoring techniques have been divided into two categories: downhole and surface monitoring. Surface monitoring is challenging because of the extremely low signal-to-noise ratio of the raw data. We applied the techniques used in earthquake seismology and developed an integrated monitoring system for mapping hydraulic fractures. The system consists of 20 to 30 state-of-the-art broadband seismographs, which are generally about hundreds times more sensible than regular geophones. We have conducted two experiments in two basins with very different geology and formation mechanism in China. In each case, we observed clear microseismic events, which may correspond to the induced seismicity directly associated with fracturing and the triggered ones at pre-existing faults. However, the magnitude of these events is generally larger than magnitude -1, approximately one to two magnitudes larger than those detected by downhole instruments. Spectrum-frequency analysis of the continuous surface recordings indicated high seismic energy associated with injection stages. The seismic energy can be back-projected to a volume that surrounds each injection stage. Imaging seismic emission volume (SEV) appears to be an effective way to map the stimulated reservior volume, as well as natural fractures.

  8. Seismic monitoring system replacement at Temelin plant

    SciTech Connect

    Baltus, R.; Palusamy, S.S.

    1996-12-01

    The VVER-1000 plants under construction at Temelin (Czech Republic) were designed with an automatic reactor trip system triggered on seismic peak accelerations. Within the plant I and C upgrade, Westinghouse designed a digital Seismic Monitoring System to be integrated in an Artificial Intelligence based Diagnostic and Monitoring System. The system meets the requirements of the emerging standards prepared by the US NRC on the basis of EPRI studies, which recommend a detailed data evaluation and a pre-shutdown plant inspection before orderly shutdown, if required, rather than immediate emergency shutdown. The paper presents the arguments about automatic trip, as discussed in an IAEA meeting attended by expert consultants from Japan, Russia, US and Eastern and Western Europe. It describes the system installed at Temelin, including the plant specific criteria for OBE exceedance. Finally it presents the capabilities and limitations of the integration into an overall Diagnostic and Monitoring System.

  9. Seismic monitoring at the Geysers Geothermal Field

    SciTech Connect

    Romero, A.E. Jr.; Kirkpatrick, A.; Majer, E.L.; Peterson, J.E. Jr.

    1994-09-01

    This report summarizes the efforts of LBL to utilize MEQ data in reservoir definition as well as in evaluating its performance. Results of the study indicate that the velocity and attenuation variations correlate with the known geology of the field. At the NW Geysers, high velocity anomalies correspond to metagraywacke and greenstone units while low velocity anomalies seem to be associated with Franciscan melanges. Low Vp/Vs and high attenuation delineate the steam reservoir suggesting undersaturation of the reservoir rocks. Ongoing monitoring of Vp/Vs may be useful in tracking the expansion of the steam zone with time. Spatial and temporal patterns of seismicity exhibit compelling correlation with geothermal exploitation. Clusters of MEQs occur beneath active injection wells and appear to shift with changing injection activities. High resolution MEQ locations hold promise for inferring fluid flow paths, especially in tracking injectate. This study has demonstrated that continuous seismic monitoring may be useful as an active reservoir management tool.

  10. Developments in seismic monitoring for risk reduction

    USGS Publications Warehouse

    Celebi, M.

    2007-01-01

    This paper presents recent state-of-the-art developments to obtain displacements and drift ratios for seismic monitoring and damage assessment of buildings. In most cases, decisions on safety of buildings following seismic events are based on visual inspections of the structures. Real-time instrumental measurements using GPS or double integration of accelerations, however, offer a viable alternative. Relevant parameters, such as the type of connections and structural characteristics (including storey geometry), can be estimated to compute drifts corresponding to several pre-selected threshold stages of damage. Drift ratios determined from real-time monitoring can then be compared to these thresholds in order to estimate damage conditions drift ratios. This approach is demonstrated in three steel frame buildings in San Francisco, California. Recently recorded data of strong shaking from these buildings indicate that the monitoring system can be a useful tool in rapid assessment of buildings and other structures following an earthquake. Such systems can also be used for risk monitoring, as a method to assess performance-based design and analysis procedures, for long-term assessment of structural characteristics of a building, and as a possible long-term damage detection tool.

  11. Seismic monitoring of an Alpine mountain river

    NASA Astrophysics Data System (ADS)

    Díaz, J.; Ruíz, M.; Crescentini, L.; Amoruso, A.; Gallart, J.

    2014-04-01

    The Canfranc underground laboratory (LSC), excavated under the Central Pyrenees, is mainly devoted to the study of phenomena which needs "cosmic silence." It also hosts a geodynamical facility, named Geodyn, which holds an accelerometer, a broadband seismometer, and two high-resolution laser strainmeters. During the routine processing of the seismic data, we detected an unusual spectral signature in the 2-10 Hz frequency band, which does not correspond to the typical sources of seismic noise and which can also be recognized in the strain records. After checking against meteorological and hydrological data, we can relate those signals to variations in the discharge by the Aragon River, an Alpine-style river in the southern Pyrenees, located about 400 m from the LSC Geodyn facility. Four main episodes have been identified since early 2011, each lasting 1-2 to 6-8 days. Additionally, a limited number of shorter episodes have also been detected. Three types of river-generated seismic events have been identified, related respectively to moderate rainfall, snowmelt, and flooding events associated to severe storms. Each of those types has distinctive characteristics which allow monitoring the hydrological events from the analysis of seismic and deformation data. A few previous studies have already described the seismic noise close to rivers with larger discharge or in small-scale experimental settings, and we are showing here that the so-called "fluvial seismology" can be useful to study the hydrological evolution of Alpine style streams and may have a potential interest for the civil authorities in charge of the management of hydrological basins.

  12. ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS

    SciTech Connect

    Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

    2008-06-17

    Earthquake source parameters underpin several aspects of nuclear explosion monitoring. Such aspects are: calibration of moment magnitudes (including coda magnitudes) and magnitude and distance amplitude corrections (MDAC); source depths; discrimination by isotropic moment tensor components; and waveform modeling for structure (including waveform tomography). This project seeks to improve methods for and broaden the applicability of estimating source parameters from broadband waveforms using the Cut-and-Paste (CAP) methodology. The CAP method uses a library of Green’s functions for a one-dimensional (1D, depth-varying) seismic velocity model. The method separates the main arrivals of the regional waveform into 5 windows: Pnl (vertical and radial components), Rayleigh (vertical and radial components) and Love (transverse component). Source parameters are estimated by grid search over strike, dip, rake and depth and seismic moment or equivalently moment magnitude, MW, are adjusted to fit the amplitudes. Key to the CAP method is allowing the synthetic seismograms to shift in time relative to the data in order to account for path-propagation errors (delays) in the 1D seismic velocity model used to compute the Green’s functions. The CAP method has been shown to improve estimates of source parameters, especially when delay and amplitude biases are calibrated using high signal-to-noise data from moderate earthquakes, CAP+.

  13. Acquisition of Crosswell Seismic Monitoring Data

    SciTech Connect

    Daley, T.M.; Niu, F.; Silver, P.G.; Majer, E.L.

    2008-02-15

    Crosswell seismic acquisition provides an ideal geometry for monitoring travel time changes in the subsurface. Analysis of delay time in terms of a characteristic frequency allows us to estimate optimal acquisition parameters (frequency and distance). We have deployed standard data acquisition equipment for continuous monitoring of crosswell travel time in two separate field experiments, with well spacing of 3 and 30 m. The acquisition hardware used for the field experiments is described, along with environmental effects (such as temperature) that influence the measurements. Two field experiments are described that correlate changes in travel time (and therefore velocity) with changes in barometric pressure. The results from the two field sites show a pressure sensitivity for velocity of 10{sup -6}/Pa to 10{sup -8}/Pa.

  14. Virtual Seismometers for Induced Seismicity Monitoring

    NASA Astrophysics Data System (ADS)

    Morency, C.; Matzel, E.

    2015-12-01

    Induced seismicity is associated with subsurface fluid injection, and puts at risk efforts to develop geologic carbon sequestration and enhanced geothermal systems. We are developing methods to monitor the microseismically active zone so that we can identify faults at risk of slipping. We are using the Virtual Seismometer Method (VSM), which is an interferometric technique that is very sensitive to the source parameters (location, mechanism and magnitude) and to the earth structure in the source region. Given an ideal geometry, that is, when two quakes are roughly in line with a recording station, the correlation of their waveforms provide a precise estimate of the Green's function between them, modified by their source mechanisms. When measuring microseismicity, this geometry is rarely ideal and we need to account for variations in the geometry as well. VSM enables us to virtually place seismometers inside a micro events cloud, where we can focus on properties directly between induced micro events, and doing so, monitor the evolution of the seismicity and precisely image potential fault zones. Here, we show that the cross-correlated signals recorded at the surface are a combination of the strain field between two sources times a moment tensor. Based on this relationship, we demonstrate how we can use this measured cross-correlated signal to invert for focal mechanism. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  15. Non-Seismic Geophysical Approaches to Monitoring

    SciTech Connect

    Hoversten, G.M.; Gasperikova, Erika

    2004-09-01

    This chapter considers the application of a number of different geophysical techniques for monitoring geologic sequestration of CO2. The relative merits of the seismic, gravity, electromagnetic (EM) and streaming potential (SP) geophysical techniques as monitoring tools are examined. An example of tilt measurements illustrates another potential monitoring technique, although it has not been studied to the extent of other techniques in this chapter. This work does not represent an exhaustive study, but rather demonstrates the capabilities of a number of geophysical techniques on two synthetic modeling scenarios. The first scenario represents combined CO2 enhance oil recovery (EOR) and sequestration in a producing oil field, the Schrader Bluff field on the north slope of Alaska, USA. The second scenario is of a pilot DOE CO2 sequestration experiment scheduled for summer 2004 in the Frio Brine Formation in South Texas, USA. Numerical flow simulations of the CO2 injection process for each case were converted to geophysical models using petrophysical models developed from well log data. These coupled flow simulation geophysical models allow comparrison of the performance of monitoring techniques over time on realistic 3D models by generating simulated responses at different times during the CO2 injection process. These time-lapse measurements are used to produce time-lapse changes in geophysical measurements that can be related to the movement of CO2 within the injection interval.

  16. An assessment of seismic monitoring in the United States; requirement for an Advanced National Seismic System

    USGS Publications Warehouse

    ,

    1999-01-01

    This report assesses the status, needs, and associated costs of seismic monitoring in the United States. It sets down the requirement for an effective, national seismic monitoring strategy and an advanced system linking national, regional, and urban monitoring networks. Modernized seismic monitoring can provide alerts of imminent strong earthquake shaking; rapid assessment of distribution and severity of earthquake shaking (for use in emergency response); warnings of a possible tsunami from an offshore earthquake; warnings of volcanic eruptions; information for correctly characterizing earthquake hazards and for improving building codes; and data on response of buildings and structures during earthquakes, for safe, cost-effective design, engineering, and construction practices in earthquake-prone regions.

  17. Marine and land active-source seismic investigation of geothermal potential, tectonic structure, and earthquake hazards in Pyramid Lake, Nevada

    NASA Astrophysics Data System (ADS)

    Eisses, A.; Kell, A. M.; Kent, G.; Driscoll, N. W.; Karlin, R. E.; Baskin, R. L.; Louie, J. N.; Smith, K. D.; Pullammanappallil, S.

    2011-12-01

    Preliminary slip rates measured across the East Pyramid Lake fault, or the Lake Range fault, help provide new estimates of extension across the Pyramid Lake basin. Multiple stratigraphic horizons spanning 48 ka were tracked throughout the lake, with layer offsets measured across all significant faults in the basin. A chronstratigraphic framework acquired from four sediment cores allows slip rates of the Lake Range and other faults to be calculated accurately. This region of the northern Walker Lake, strategically placed between the right-lateral strike-slip faults of Honey and Eagle Lakes to the north, and the normal fault bounded basins to the southwest (e.g., Tahoe, Carson), is critical in understanding the underlying structural complexity that is not only necessary for geothermal exploration, but also earthquake hazard assessment due to the proximity of the Reno-Sparks metropolitan area. In addition, our seismic CHIRP imaging with submeter resolution allows the construction of the first fault map of Pyramid Lake. The Lake Range fault can be obviously traced west of Anahoe Island extending north along the east end of the lake in numerous CHIRP lines. Initial drafts of the fault map reveal active transtension through a series of numerous, small, northwest striking, oblique-slip faults in the north end of the lake. A previously field mapped northwest striking fault near Sutcliff can be extended into the west end of Pyramid Lake. This fault map, along with the calculated slip rate of the Lake Range, and potentially multiple other faults, gives a clearer picture into understanding the geothermal potential, tectonic regime and earthquake hazards in the Pyramid Lake basin and the northern Walker Lane. These new results have also been merged with seismicity maps, along with focal mechanisms for the larger events to begin to extend our fault map in depth.

  18. Real-time seismic monitoring of instrumented hospital buildings

    USGS Publications Warehouse

    Kalkan, Erol; Fletcher, Jon Peter B.; Leith, William S.; McCarthy, William S.; Banga, Krishna

    2012-01-01

    In collaboration with the Department of Veterans Affairs (VA), the U.S. Geological Survey's National Strong Motion Project has recently installed sophisticated seismic monitoring systems to monitor the structural health of two hospital buildings at the Memphis VA Medical Center in Tennessee. The monitoring systems in the Bed Tower and Spinal Cord Injury buildings combine sensing technologies with an on-site computer to capture and analyze seismic performance of buildings in near-real time.

  19. Rifting process of the Izu-Ogasawara-Mariana arc-backarc system inferred from active source seismic studies

    NASA Astrophysics Data System (ADS)

    Takahashi, N.; Kodaira, S.; Miura, S.; Sato, T.; Yamashita, M.; No, T.; Takizawa, K.; Kaiho, Y.; Kaneda, Y.

    2008-12-01

    The Izu-Ogasawara-Mariana (IBM) arc-backarc system has continued the crustal growth through crustal thickening by magmatic activities and crustal thinning by backarc opening. Tatsumi et al (2008) proposed petrological crustal growth model started from basaltic magmas rising from the slab, and showed the consistency with the seismic velocity model. Although crustal growth by the crustal thickening are modeled, crustal structural change by the backarc opening are not still unknown yet. The Shikoku Basin and Parece Vela Basin were formed by the backarc opening during approximately 15-30 Ma. Since 6 Ma, the Mariana Trough has opened and the stage already moved to spreading process from rifting process. In the northern Izu-Ogasawara arc, the Sumisu rift is in the initial rifting stage. Therefore, understanding of the crustal change by the backarc opening from rifting to spreading is indispensable to know the crustal growth of whole Izu-Ogasawara-Mariana island arc. Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has carried out seismic studies using a multichannel reflection survey system and ocean bottom seismographs (OBSs) around the IBM arc since 2003 (Takahashi et al., 2007; Kodaira et al., 2007; Takahashi et al., 2008; Kodaira et al., 2008). We already obtained eight P-wave velocity models across the IBM arc and these structures record the crustal structural change during the backarc opening process from the rifting stage to the spreading stage. As the results, we identified characteristics of the crustal structural change accompanied with backarc opening as follows. (1) Beneath the initial rifting stage without normal faults, for example, in the northern tip of the Mariana Trough, crustal thickening are identified. (2) Beneath the initial rifting stage with normal faults, for example, in the Sumisu Rift, the crustal thickness is almost similar to that beneath the volcanic front. Although an existence of the crust-mantle transition layer with

  20. Optimizing Seismic Monitoring Networks for EGS and Conventional Geothermal Projects

    NASA Astrophysics Data System (ADS)

    Kraft, Toni; Herrmann, Marcus; Bethmann, Falko; Stefan, Wiemer

    2013-04-01

    In the past several years, geological energy technologies receive growing attention and have been initiated in or close to urban areas. Some of these technologies involve injecting fluids into the subsurface (e.g., oil and gas development, waste disposal, and geothermal energy development) and have been found or suspected to cause small to moderate sized earthquakes. These earthquakes, which may have gone unnoticed in the past when they occurred in remote sparsely populated areas, are now posing a considerable risk for the public acceptance of these technologies in urban areas. The permanent termination of the EGS project in Basel, Switzerland after a number of induced ML~3 (minor) earthquakes in 2006 is one prominent example. It is therefore essential for the future development and success of these geological energy technologies to develop strategies for managing induced seismicity and keeping the size of induced earthquakes at a level that is acceptable to all stakeholders. Most guidelines and recommendations on induced seismicity published since the 1970ies conclude that an indispensable component of such a strategy is the establishment of seismic monitoring in an early stage of a project. This is because an appropriate seismic monitoring is the only way to detect and locate induced microearthquakes with sufficient certainty to develop an understanding of the seismic and geomechanical response of the reservoir to the geotechnical operation. In addition, seismic monitoring lays the foundation for the establishment of advanced traffic light systems and is therefore an important confidence building measure towards the local population and authorities. We have developed an optimization algorithm for seismic monitoring networks in urban areas that allows to design and evaluate seismic network geometries for arbitrary geotechnical operation layouts. The algorithm is based on the D-optimal experimental design that aims to minimize the error ellipsoid of the linearized

  1. Network Optimization for Induced Seismicity Monitoring in Urban Areas

    NASA Astrophysics Data System (ADS)

    Kraft, T.; Husen, S.; Wiemer, S.

    2012-12-01

    With the global challenge to satisfy an increasing demand for energy, geological energy technologies receive growing attention and have been initiated in or close to urban areas in the past several years. Some of these technologies involve injecting fluids into the subsurface (e.g., oil and gas development, waste disposal, and geothermal energy development) and have been found or suspected to cause small to moderate sized earthquakes. These earthquakes, which may have gone unnoticed in the past when they occurred in remote sparsely populated areas, are now posing a considerable risk for the public acceptance of these technologies in urban areas. The permanent termination of the EGS project in Basel, Switzerland after a number of induced ML~3 (minor) earthquakes in 2006 is one prominent example. It is therefore essential to the future development and success of these geological energy technologies to develop strategies for managing induced seismicity and keeping the size of induced earthquake at a level that is acceptable to all stakeholders. Most guidelines and recommendations on induced seismicity published since the 1970ies conclude that an indispensable component of such a strategy is the establishment of seismic monitoring in an early stage of a project. This is because an appropriate seismic monitoring is the only way to detect and locate induced microearthquakes with sufficient certainty to develop an understanding of the seismic and geomechanical response of the reservoir to the geotechnical operation. In addition, seismic monitoring lays the foundation for the establishment of advanced traffic light systems and is therefore an important confidence building measure towards the local population and authorities. We have developed an optimization algorithm for seismic monitoring networks in urban areas that allows to design and evaluate seismic network geometries for arbitrary geotechnical operation layouts. The algorithm is based on the D-optimal experimental

  2. TOMO3D: 3-D joint refraction and reflection traveltime tomography parallel code for active-source seismic data—synthetic test

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallarès, V.; Miniussi, A.; Ranero, C. R.

    2015-10-01

    We present a new 3-D traveltime tomography code (TOMO3D) for the modelling of active-source seismic data that uses the arrival times of both refracted and reflected seismic phases to derive the velocity distribution and the geometry of reflecting boundaries in the subsurface. This code is based on its popular 2-D version TOMO2D from which it inherited the methods to solve the forward and inverse problems. The traveltime calculations are done using a hybrid ray-tracing technique combining the graph and bending methods. The LSQR algorithm is used to perform the iterative regularized inversion to improve the initial velocity and depth models. In order to cope with an increased computational demand due to the incorporation of the third dimension, the forward problem solver, which takes most of the run time (˜90 per cent in the test presented here), has been parallelized with a combination of multi-processing and message passing interface standards. This parallelization distributes the ray-tracing and traveltime calculations among available computational resources. The code's performance is illustrated with a realistic synthetic example, including a checkerboard anomaly and two reflectors, which simulates the geometry of a subduction zone. The code is designed to invert for a single reflector at a time. A data-driven layer-stripping strategy is proposed for cases involving multiple reflectors, and it is tested for the successive inversion of the two reflectors. Layers are bound by consecutive reflectors, and an initial velocity model for each inversion step incorporates the results from previous steps. This strategy poses simpler inversion problems at each step, allowing the recovery of strong velocity discontinuities that would otherwise be smoothened.

  3. Seismic monitoring of Central Asia territory in KNDC.

    NASA Astrophysics Data System (ADS)

    Mukambayev, Aidyn; Mikhailova, Natalia

    2015-04-01

    The Central Asia territory includes the territory of five post-Soviet countries: Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. Every country has its own independent network of seismic observations and Data Processing Center aimed at every day seismic monitoring of one country territory. However, seismic hazard of Central Asia territory is stipulated by one geodynamic system that generates simultaneous large earthquakes on the territory of different countries. Thus, it is necessary to observe seismic situation for the whole region for emergency situations and for compilation of joint seismic bulletins of Central Asia region. A new contemporary network of seismic observations operated by the Institute of Geophysical Researches has been installed in Kazakhstan during last 15 years. Mainly, these are seismic arrays located throughout the country perimeter. The arrays were constructed under support of the CTBTO, and AFTAC. There are also IRIS and CAREMON stations. All data arrive to KNDC (Kazakhstan National Data Center) in real time mode. In addition, KNDC receives data in real time from stations Zalesovo (Russia), Alibek (Turkmenistan), Ala-Archa and Tokmak (Kyrgyzstan). Arrival times in the form of tables are received with 24-hours delay from almost 20 Kazakhstan stations belonging to SEME MES RK. This observation system allows monitoring the Central Asian seismicity by earthquakes with representative magnitude more than 3.5. In some regions, the events with magnitude 1.5 are recorded. As result, different products with different operativity are created for Central Asia territory: -bulletin of urgent alerts; -automatic seismic bulletin; -interactive seismic bulletin; -joint seismic operative bulletin by data arrived on-line and in table form. After that, in retrospective mode, the events nature is identified to discriminate mining explosions (up to 4000 per year) and natural earthquakes (up to 15000 per year). The results are available at KNDC web

  4. Seismic activity monitoring in the Izvorul Muntelui dam region

    NASA Astrophysics Data System (ADS)

    Borleanu, Felix; Otilia Placinta, Anca; Popa, Mihaela; Adelin Moldovan, Iren; Popescu, Emilia

    2016-04-01

    Earthquakes occurrences near the artificial water reservoirs are caused by stress variation due to the weight of water, weakness of fractures or faults and increasing of pore pressure in crustal rocks. In the present study we aim to investigate how Izvorul Muntelui dam, located in the Eastern Carpathians influences local seismicity. For this purpose we selected from the seismic bulletins computed within National Data Center of National Institute for Earth Physics, Romania, crustal events occurred between 984 and 2015 in a range of 0.3 deg around the artificial lake. Subsequently to improve the seismic monitoring of the region we applied a cross-correlation detector on the continuous recordings of Bicaz (BIZ) seismic stations. Besides the tectonic events we detected sources within this region that periodically generate artificial evens. We couldn't emphasize the existence of a direct correlation between the water level variations and natural seismicity of the investigated area.

  5. Seismic monitoring at Deception Island volcano (Antarctica): Recent advances

    NASA Astrophysics Data System (ADS)

    Carmona, E.; Almendros, J.; Martín, R.; Cortés, G.; Alguacil, G.; Moreno, J.; Martín, B.; Martos, A.; Serrano, I.; Stich, D.; Ibáñez, J. M.

    2012-04-01

    Deception Island (South Shetland Island, Antarctica) is an active volcano with recent eruptions (e.g. 1967, 1969 and 1970). It is also among the Antarctic sites most visited by tourists. Besides, there are currently two scientific bases operating during the austral summers, usually from late November to early March. For these reasons it is necessary to deploy a volcano monitoring system as complete as possible, designed specifically to endure the extreme conditions of the volcanic environment and the Antarctic climate. The Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR) performs seismic monitoring on Deception Island since 1994 during austral summer surveys. The seismicity basically includes volcano-tectonic earthquakes, long-period events and volcanic tremor, among other signals. The level of seismicity is moderate, except for a seismo-volcanic crisis in 1999. The seismic monitoring system has evolved during these years, following the trends of the technological developments and software improvements. Recent advances have been mainly focused on: (1) the improvement of the seismic network introducing broadband stations and 24-bit data acquisition systems; (2) the development of a short-period seismic array, with a 12-channel, 24-bit data acquisition system; (3) the implementation of wireless data transmission from the network stations and also from the seismic array to a recording center, allowing for real-time monitoring; (4) the efficiency of the power supply systems and the monitoring of the battery levels and power consumption; (5) the optimization of data analysis procedures, including database management, automated event recognition tools for the identification and classification of seismo-volcanic signals, and apparent slowness vector estimates using seismic array data; (6) the deployment of permanent seismic stations and the transmission of data during the winter using a satellite connection. A single permanent station is operating

  6. Seismic monitoring of the Olkaria Geothermal area, Kenya Rift valley

    NASA Astrophysics Data System (ADS)

    Simiyu, Silas M.; Keller, G. Randy

    2000-01-01

    Seismic monitoring of the Olkaria Geothermal area in the southern Rift Valley region of Kenya has been carried out since 1985. The initial purpose of this effort was to determine the background level of seismicity before full exploitation of the geothermal resource was started. This monitoring began with one seismic station. However, since May 1996, a seismic network comprising six stations was operated and focused mainly on the East Production Field. During the 5 months of network recording up to mid-September 1996, more than 460 local events originating within the Olkaria Geothermal area ( Ts- Tp<5 s) were recorded, out of which 123 were well-located. Also, 62 events were recorded at regional distances (5 s< Ts- Tp<40 s), and 44 events at teleseismic distance ( Ts- Tp>40 s). During this period, the local microseismicity was found to be continuous with swarms occurring every 4-5 days. Duration magnitudes based on the coda length did not exceed 3.0. Preliminary spectral analysis shows three kinds of seismic signals, with only the first type displaying well-defined P- and S-phases. The seismicity is mainly concentrated in the central area of the recording network, and the linear alignments in the epicenters are striking. A prominent alignment occurs along the Ololbutot fault zone extending from the northern end of the greater Olkaria volcanic complex to the south near the southern terminus of Hell's gorge. Two other prominent alignments occur along NW-SE trends that coincide with fault zones which have been detected by geological and gravity studies. Consequently, they are interpreted to be associated with fluid movement in the geothermal field. These preliminary results suggest that seismic monitoring will be useful to both monitor the field during production and to help site additional wells.

  7. MSNoise: a Python Package for Monitoring Seismic Velocity Changes using Ambient Seismic Noise

    NASA Astrophysics Data System (ADS)

    Lecocq, Thomas; Caudron, Corentin; Brenguier, Florent

    2014-05-01

    We present MSNoise, a complete software suite to compute relative seismic velocity changes under a seismic network, using ambient seismic noise. The whole is written in Python, from the monitoring of data archives, to the production of high quality figures. All steps have been optimized to only compute the necessary steps and to use 'job'-based processing. All steps can be changed by matching the in/outs. MSNoise exposes an API for communication with the data archive and the database. We present a validation of the software on a dataset acquired during the UnderVolc project on the Piton de la Fournaise Volcano, La Réunion Island, France, for which precursory relative changes of seismic velocity are visible for three eruptions betwee 2009 and 2011. MSNoise is available on http://www.msnoise.org

  8. Scalable Probabilistic Inference for Global Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Arora, N. S.; Dear, T.; Russell, S.

    2011-12-01

    We describe a probabilistic generative model for seismic events, their transmission through the earth, and their detection (or mis-detection) at seismic stations. We also describe an inference algorithm that constructs the most probable event bulletin explaining the observed set of detections. The model and inference are called NET-VISA (network processing vertically integrated seismic analysis) and is designed to replace the current automated network processing at the IDC, the SEL3 bulletin. Our results (attached table) demonstrate that NET-VISA significantly outperforms SEL3 by reducing the missed events from 30.3% down to 12.5%. The difference is even more dramatic for smaller magnitude events. NET-VISA has no difficulty in locating nuclear explosions as well. The attached figure demonstrates the location predicted by NET-VISA versus other bulletins for the second DPRK event. Further evaluation on dense regional networks demonstrates that NET-VISA finds many events missed in the LEB bulletin, which is produced by the human analysts. Large aftershock sequences, as produced by the 2004 December Sumatra earthquake and the 2011 March Tohoku earthquake, can pose a significant load for automated processing, often delaying the IDC bulletins by weeks or months. Indeed these sequences can overload the serial NET-VISA inference as well. We describe an enhancement to NET-VISA to make it multi-threaded, and hence take full advantage of the processing power of multi-core and -cpu machines. Our experiments show that the new inference algorithm is able to achieve 80% efficiency in parallel speedup.

  9. Borehole seismic monitoring of seismic stimulation at OccidentalPermian Ltd's -- South Wason Clear Fork Unit

    SciTech Connect

    Daley, Tom; Majer, Ernie

    2007-04-30

    Seismic stimulation is a proposed enhanced oil recovery(EOR) technique which uses seismic energy to increase oil production. Aspart of an integrated research effort (theory, lab and field studies),LBNL has been measuring the seismic amplitude of various stimulationsources in various oil fields (Majer, et al., 2006, Roberts,et al.,2001, Daley et al., 1999). The amplitude of the seismic waves generatedby a stimulation source is an important parameter for increased oilmobility in both theoretical models and laboratory core studies. Theseismic amplitude, typically in units of seismic strain, can be measuredin-situ by use of a borehole seismometer (geophone). Measuring thedistribution of amplitudes within a reservoir could allow improved designof stimulation source deployment. In March, 2007, we provided in-fieldmonitoring of two stimulation sources operating in Occidental (Oxy)Permian Ltd's South Wasson Clear Fork (SWCU) unit, located near DenverCity, Tx. The stimulation source is a downhole fluid pulsation devicedeveloped by Applied Seismic Research Corp. (ASR). Our monitoring used aborehole wall-locking 3-component geophone operating in two nearbywells.

  10. SIG-VISA: Signal-based Vertically Integrated Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Moore, D.; Mayeda, K. M.; Myers, S. C.; Russell, S.

    2013-12-01

    Traditional seismic monitoring systems rely on discrete detections produced by station processing software; however, while such detections may constitute a useful summary of station activity, they discard large amounts of information present in the original recorded signal. We present SIG-VISA (Signal-based Vertically Integrated Seismic Analysis), a system for seismic monitoring through Bayesian inference on seismic signals. By directly modeling the recorded signal, our approach incorporates additional information unavailable to detection-based methods, enabling higher sensitivity and more accurate localization using techniques such as waveform matching. SIG-VISA's Bayesian forward model of seismic signal envelopes includes physically-derived models of travel times and source characteristics as well as Gaussian process (kriging) statistical models of signal properties that combine interpolation of historical data with extrapolation of learned physical trends. Applying Bayesian inference, we evaluate the model on earthquakes as well as the 2009 DPRK test event, demonstrating a waveform matching effect as part of the probabilistic inference, along with results on event localization and sensitivity. In particular, we demonstrate increased sensitivity from signal-based modeling, in which the SIGVISA signal model finds statistical evidence for arrivals even at stations for which the IMS station processing failed to register any detection.

  11. Bayesian Inference for Signal-Based Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Moore, D.

    2015-12-01

    Traditional seismic monitoring systems rely on discrete detections produced by station processing software, discarding significant information present in the original recorded signal. SIG-VISA (Signal-based Vertically Integrated Seismic Analysis) is a system for global seismic monitoring through Bayesian inference on seismic signals. By modeling signals directly, our forward model is able to incorporate a rich representation of the physics underlying the signal generation process, including source mechanisms, wave propagation, and station response. This allows inference in the model to recover the qualitative behavior of recent geophysical methods including waveform matching and double-differencing, all as part of a unified Bayesian monitoring system that simultaneously detects and locates events from a global network of stations. We demonstrate recent progress in scaling up SIG-VISA to efficiently process the data stream of global signals recorded by the International Monitoring System (IMS), including comparisons against existing processing methods that show increased sensitivity from our signal-based model and in particular the ability to locate events (including aftershock sequences that can tax analyst processing) precisely from waveform correlation effects. We also provide a Bayesian analysis of an alleged low-magnitude event near the DPRK test site in May 2010 [1] [2], investigating whether such an event could plausibly be detected through automated processing in a signal-based monitoring system. [1] Zhang, Miao and Wen, Lianxing. "Seismological Evidence for a Low-Yield Nuclear Test on 12 May 2010 in North Korea". Seismological Research Letters, January/February 2015. [2] Richards, Paul. "A Seismic Event in North Korea on 12 May 2010". CTBTO SnT 2015 oral presentation, video at https://video-archive.ctbto.org/index.php/kmc/preview/partner_id/103/uiconf_id/4421629/entry_id/0_ymmtpps0/delivery/http

  12. Enhancing Seismic Monitoring Capability for Hydraulic Fracturing Induced Seismicity in Canada

    NASA Astrophysics Data System (ADS)

    Kao, H.; Cassidy, J. F.; Farahbod, A.; Lamontagne, M.

    2012-12-01

    The amount of natural gas produced from unconventional sources, such as the shale gas, has increased dramatically since the last decade. One of the key factors in the success of shale gas production is the application of hydraulic fracturing (also known as "fracking") to facilitate the efficient recovery of natural gas from shale matrices. As the fracking operation becomes routine in all major shale gas fields, its potential to induce local earthquakes at some locations has become a public concern. To address this concern, Natural Resources Canada has initiated a research effort to investigate the potential links between fracking operations and induced seismicity in some major shale gas basins of Canada. This federal-provincial collaborative research aims to assess if shale gas fracking can alter regional pattern of background seismicity and if so, what the relationship between how fracking is conducted and the maximum magnitude of induced seismicity would be. Other objectives include the investigation of the time scale of the interaction between fracking events and induced seismicity and the evaluation of induced seismicity potential for shale gas basins under different tectonic/geological conditions. The first phase of this research is to enhance the detection and monitoring capability for seismicity possibly related to shale gas recovery in Canada. Densification of the Canadian National Seismograph Network (CNSN) is currently underway in northeast British Columbia where fracking operations are taking place. Additional seismic stations are planned for major shale gas basins in other regions where fracking might be likely in the future. All newly established CNSN stations are equipped with broadband seismographs with real-time continuous data transmission. The design goal of the enhanced seismic network is to significantly lower the detection threshold such that the anticipated low-magnitude earthquakes that might be related to fracking operations can be

  13. Seismic monitoring at Cascade Volcanic Centers, 2004?status and recommendations

    USGS Publications Warehouse

    Moran, Seth C.

    2004-01-01

    The purpose of this report is to assess the current (May, 2004) status of seismic monitoring networks at the 13 major Cascade volcanic centers. Included in this assessment are descriptions of each network, analyses of the ability of each network to detect and to locate seismic activity, identification of specific weaknesses in each network, and a prioritized list of those networks that are most in need of additional seismic stations. At the outset it should be recognized that no Cascade volcanic center currently has an adequate seismic network relative to modern-day networks at Usu Volcano (Japan) or Etna and Stromboli volcanoes (Italy). For a system the size of Three Sisters, for example, a modern-day, cutting-edge seismic network would ideally consist of a minimum of 10 to 12 short-period three-component seismometers (for determining particle motions, reliable S-wave picks, moment tensor inversions, fault-plane solutions, and other important seismic parameters) and 7 to 10 broadband sensors (which, amongst other considerations, enable detection and location of very long period (VLP) and other low-frequency events, moment tensor inversions, and, because of their wide dynamic range, on-scale recording of large-amplitude events). Such a dense, multi component seismic network would give the ability to, for example, detect in near-real-time earthquake migrations over a distance of ~0.5km or less, locate tremor sources, determine the nature of a seismic source (that is, pure shear, implosive, explosive), provide on-scale recordings of very small and very large-amplitude seismic signals, and detect localized changes in seismic stress tensor orientations caused by movement of magma bodies. However, given that programmatic resources are currently limited, installation of such networks at this time is unrealistic. Instead, this report focuses on identifying what additional stations are needed to guarantee that anomalous seismicity associated with volcanic unrest will be

  14. Szilard Prize Lecture: Seismic Monitoring of Nuclear Explosions

    NASA Astrophysics Data System (ADS)

    Richards, Paul

    2006-04-01

    Seismic monitoring of the more than 2000 nuclear test explosions since 1945 has been vigorously pursued, both to track the weapons development of potential adversaries, and to support initiatives in nuclear arms control, including various test ban treaties. Major funding from the US Department of Defense built up new global seismographic networks and over several decades established practical capability in monitoring nuclear explosions ``teleseismically'' (i.e. from distances more than about 1500 km), for tests that the testing nation did not attempt to conceal. What then is the capability to monitor compliance with, for example, the Comprehensive Nuclear-Test-Ban Treaty (CTBT) of 1996, particularly if evasion scenarios are considered? Note that the CTBT, though not ratified by some countries (including the US), is now being monitored by networks that include seismographic stations at ``regional'' distances (< 1500 km) from candidate explosion locations. Years of R and D have shown that regional signals can be used to monitor down to yields significantly lower than can be detected and identified teleseismically. A US National Academy of Sciences study in 2002 concluded that ``an underground nuclear explosion cannot be confidently hidden if its yield is larger than 1 or 2 kt.'' About 1000 earthquakes and chemical explosions are now detected per day, and documented via seismic data, providing plenty of challenges for nuclear explosion monitoring organizations. Explosion monitoring capability will improve in many parts of the world, due to the growth of networks that monitor even small earthquakes to study seismic hazard. But political problems can impede improved international explosion monitoring, due to national restrictions on data access.

  15. Monitoring southwest Greenland's ice sheet melt with ambient seismic noise.

    PubMed

    Mordret, Aurélien; Mikesell, T Dylan; Harig, Christopher; Lipovsky, Bradley P; Prieto, Germán A

    2016-05-01

    The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth's crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. Seasonal loading and unloading of glacial mass induces strain in the crust, and these strains then result in seismic velocity changes due to poroelastic processes. Our method provides a new and independent way of monitoring (in near real time) ice sheet mass balance, yielding new constraints on ice sheet evolution and its contribution to global sea-level changes. An increased number of seismic stations in the vicinity of ice sheets will enhance our ability to create detailed space-time records of ice mass variations. PMID:27386524

  16. Monitoring southwest Greenland's ice sheet melt with ambient seismic noise.

    PubMed

    Mordret, Aurélien; Mikesell, T Dylan; Harig, Christopher; Lipovsky, Bradley P; Prieto, Germán A

    2016-05-01

    The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth's crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. Seasonal loading and unloading of glacial mass induces strain in the crust, and these strains then result in seismic velocity changes due to poroelastic processes. Our method provides a new and independent way of monitoring (in near real time) ice sheet mass balance, yielding new constraints on ice sheet evolution and its contribution to global sea-level changes. An increased number of seismic stations in the vicinity of ice sheets will enhance our ability to create detailed space-time records of ice mass variations.

  17. Korea Integrated Seismic System tool(KISStool) for seismic monitoring and data sharing at the local data center

    NASA Astrophysics Data System (ADS)

    Park, J.; Chi, H. C.; Lim, I.; Jeong, B.

    2011-12-01

    The Korea Integrated Seismic System(KISS) is a back-bone seismic network which distributes seismic data to different organizations in near-real time at Korea. The association of earthquake monitoring institutes has shared their seismic data through the KISS from 2003. Local data centers operating remote several stations need to send their free field seismic data to NEMA(National Emergency Management Agency) by the law of countermeasure against earthquake hazard in Korea. It is very important the efficient tool for local data centers which want to rapidly detect local seismic intensity and to transfer seismic event information toward national wide data center including PGA, PGV, dominant frequency of P-wave, raw data, and etc. We developed the KISStool(Korea Integrated Seismic System tool) for easy and convenient operation seismic network in local data center. The KISStool has the function of monitoring real time waveforms by clicking station icon on the Google map and real time variation of PGA, PGV, and other data by opening the bar type monitoring section. If they use the KISStool, any local data center can transfer event information to NEMA(National Emergency Management Agency), KMA(Korea Meteorological Agency) or other institutes through the KISS using UDP or TCP/IP protocols. The KISStool is one of the most efficient methods to monitor and transfer earthquake event at local data center in Korea. KIGAM will support this KISStool not only to the member of the monitoring association but also local governments.

  18. ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS

    SciTech Connect

    Helmberger, Donald V.; Tromp, Jeroen; Rodgers, Arthur J.

    2008-10-17

    This quarter, we have focused on several tasks: (1) Building a high-quality catalog of earthquake source parameters for the Middle East and East Asia. In East Asia, we computed source parameters using the CAP method for a set of events studied by Herrman et al., (MRR, 2006) using a complete waveform technique. Results indicated excellent agreement with the moment magnitudes in the range 3.5 -5.5. Below magnitude 3.5 the scatter increases. For events with more than 2-3 observations at different azimuths, we found good agreement of focal mechanisms. Depths were generally consistent, although differences of up to 10 km were found. These results suggest that CAP modeling provides estimates of source parameters at least as reliable as complete waveform modeling techniques. However, East Asia and the Yellow Sea Korean Paraplatform (YSKP) region studied are relatively laterally homogeneous and may not benefit from the CAP method’s flexibility to shift waveform segments to account for path-dependent model errors. A more challenging region to study is the Middle East where strong variations in sedimentary basin, crustal thickness and crustal and mantle seismic velocities greatly impact regional wave propagation. We applied the CAP method to a set of events in and around Iran and found good agreement between estimated focal mechanisms and those reported by the Global Centroid Moment Tensor (CMT) catalog. We found a possible bias in the moment magnitudes that may be due to the thick low-velocity crust in the Iranian Plateau. (2) Testing Methods on a Lifetime Regional Data Set. In particular, the recent 2/21/08 Nevada Event and Aftershock Sequence occurred in the middle of USArray, producing over a thousand records per event. The tectonic setting is quite similar to Central Iran and thus provides an excellent testbed for CAP+ at ranges out to 10°, including extensive observations of crustal thinning and thickening and various Pnl complexities. Broadband modeling in 1D, 2D

  19. Continuous monitoring of crosswell seismic travel time

    SciTech Connect

    Daley, Thomas M.; Silver, Paul G.; Niu, Fenglin; Majer, Ernest L.

    2006-04-14

    In two separate shallow field experiments, at two distancescales, we have used continuous monitoring to estimate the effect ofbarometric pressure on crosswell travel time and thereby calibrated thestress sensitivity of the rock volume between the wells. In a 3 mexperiment we found a stress sensitivity of 10-6/Pa while in a 30 mexperiment the sensitivity was 5 x 10-8 /Pa. Results from a deeper (1km), 2 month experiment at the San Andreas fault observation boreholeswill be presented if analysis is completed.

  20. Single-station monitoring of volcanoes using seismic ambient noise

    NASA Astrophysics Data System (ADS)

    De Plaen, Raphael S. M.; Lecocq, Thomas; Caudron, Corentin; Ferrazzini, Valérie; Francis, Olivier

    2016-08-01

    Seismic ambient noise cross correlation is increasingly used to monitor volcanic activity. However, this method is usually limited to volcanoes equipped with large and dense networks of broadband stations. The single-station approach may provide a powerful and reliable alternative to the classical "cross-station" approach when measuring variation of seismic velocities. We implemented it on the Piton de la Fournaise in Reunion Island, a very active volcano with a remarkable multidisciplinary continuous monitoring. Over the past decade, this volcano has been increasingly studied using the traditional cross-correlation technique and therefore represents a unique laboratory to validate our approach. Our results, tested on stations located up to 3.5 km from the eruptive site, performed as well as the classical approach to detect the volcanic eruption in the 1-2 Hz frequency band. This opens new perspectives to successfully forecast volcanic activity at volcanoes equipped with a single three-component seismometer.

  1. High efficiency TDM/WDM architectures for seismic reservoir monitoring

    NASA Astrophysics Data System (ADS)

    Nash, P.; Strudley, A.; Crickmore, R.; DeFreitas, J.

    2009-10-01

    Fibre-optic seismic sensor systems for permanent monitoring of oil and gas reservoirs have been under development for several years. Such systems, which may comprise over 30 000 sensor channels, require an efficient optical multiplexing architecture. We report test results from a time and wavelength based multiplexing architecture combining up to 256 sensor channels onto a single optical fibre pair, while still allowing low system noise floor and dynamic range over 180 dB.

  2. High-Resolution Seismic Reflection to Monitor Change

    NASA Astrophysics Data System (ADS)

    Miller, R. D.; Raef, A. E.; Lambrecht, J. L.; Byrnes, A. P.

    2006-05-01

    High-resolution seismic reflection has proven a valuable tool detecting changes in fluid composition, rock petrophysical properties, and structures critical to reservoir production management and groundwater protection in Kansas. Surface seismic reflection is not a method that lends itself to direct detection and delineation of boundaries between different fluid compositions in porous media. However, time-lapse seismic does appear to have been successful identifying areas where calculated changes in seismic characteristics (specifically velocity) are greater than 10% at a miscible CO2 flood in Russell County, Kansas. Empirically a 10% change in seismic velocity has proven to be the minimum practical threshold where signal emerging from the noise can be interpreted with any degree of confidence. This change in velocity occurs when the saturation of injection CO2 exceeds 30% of the total pore fluid at this site. To evaluate the potential of high-resolution seismic reflection to monitor the injection in a miscible CO2 enhanced oil recovery pilot study in a 900 m deep 5 m thick oolitic carbonate petroleum reservoir, a 4-D seismic reflection program was undertaken that includes 12 different 3-D surveys over 6 years. The first 3 years (8 surveys) were designed to specifically address the potential application of this method to enhanced oil recovery. The last 3 years (3 surveys) are intended to evaluate the effective of seismic in providing the assurances necessary for CO2 sequestration. Collapse structures related to karst features and anthropogenic leaching resulting from faulty bore fluid containment have posed serious threats to the quality of groundwater above the Hutchinson Salt Member of the Permian Wellington Formation in central Kansas. High-resolution seismic reflection played a key role in characterizing the preferential growth of a sinkhole resulting from the dissolution of the Hutchinson Salt in Pawnee County, Kansas. Salt leaching was instigated by

  3. A wireless sensor network for monitoring volcano-seismic signals

    NASA Astrophysics Data System (ADS)

    Lopes Pereira, R.; Trindade, J.; Gonçalves, F.; Suresh, L.; Barbosa, D.; Vazão, T.

    2014-12-01

    Monitoring of volcanic activity is important for learning about the properties of each volcano and for providing early warning systems to the population. Monitoring equipment can be expensive, and thus the degree of monitoring varies from volcano to volcano and from country to country, with many volcanoes not being monitored at all. This paper describes the development of a wireless sensor network (WSN) capable of collecting geophysical measurements on remote active volcanoes. Our main goals were to create a flexible, easy-to-deploy and easy-to-maintain, adaptable, low-cost WSN for temporary or permanent monitoring of seismic tremor. The WSN enables the easy installation of a sensor array in an area of tens of thousands of m2, allowing the location of the magma movements causing the seismic tremor to be calculated. This WSN can be used by recording data locally for later analysis or by continuously transmitting it in real time to a remote laboratory for real-time analyses. We present a set of tests that validate different aspects of our WSN, including a deployment on a suspended bridge for measuring its vibration.

  4. Seismic monitoring of rockfalls at Spitz quarry (NÖ, Austria)

    NASA Astrophysics Data System (ADS)

    del Puy Papí Isaba, María; Brückl, Ewald; Roncat, Andreas; Schweigl, Joachim

    2016-04-01

    In the recent past, significant rockfalls, which pose a danger to persons, railways and roads, occurred in the quarry of Spitz (NÖ-Austria). An existing seismic warning system did not fulfill the expected efficiency and reliability standards since the ratio of well-detected events to undetected events or false alarms was not satisfactory. Our aim was to analyze how a seismic warning system must be designed in order to overcome these deficiencies. A small-scale seismic network was deployed in the Spitz quarry to evaluate the possibility of improving the early-warning rockfall monitoring network by means of seismic observations. A new methodology based on seismic methods, which enables the detection and location of rockfalls above a critical size, was developed. In order to perform this task, a small-scale (200x200 m2) passive seismic network comprised of 7 monitoring seismic stations acquiring data in continuous mode was established in the quarry of Spitz so that it covered the rockfall hazard area. On the 2nd of October 2015, an induced rockfall experiment was performed. It began at 09:00 a.m (local time, 07:00 UTC) and lasted about 1.5 hours. The entire data set was analyzed using the pSysmon software. In order to locate the impact point of the rock falls, we used a procedure based on the back-projection of the maximum resultant amplitude recorded at each station of the network within a time window to every grid-point covering the whole area of interest. In order to verify the performance of the employed algorithm for detection and localization, we performed man-induced rock falls. We also used a terrestrial laser scanner and a camera, not only to draw the rockfall block trajectories, but also to determine the volume of rock lost or gained in the different areas of the quarry. This allowed us to relate the lost mass with the strength of the collision (Pseudo-magnitude) of the rockfall, and draw and rebuild their associated trajectory. The location test performed

  5. Seismic Characterization of Coal-Mining Seismicity in Utah for CTBT Monitoring

    SciTech Connect

    Arabasz, W J; Pechmann, J C

    2001-03-01

    Underground coal mining (down to {approx}0.75 km depth) in the contiguous Wasatch Plateau (WP) and Book Cliffs (BC) mining districts of east-central Utah induces abundant seismicity that is monitored by the University of Utah regional seismic network. This report presents the results of a systematic characterization of mining seismicity (magnitude {le} 4.2) in the WP-BC region from January 1978 to June 2000-together with an evaluation of three seismic events (magnitude {le} 4.3) associated with underground trona mining in southwestern Wyoming during January-August 2000. (Unless specified otherwise, magnitude implies Richter local magnitude, M{sub L}.) The University of Utah Seismograph Stations (UUSS) undertook this cooperative project to assist the University of California Lawrence Livermore National Laboratory (LLNL) in research and development relating to monitoring the Comprehensive Test Ban Treaty (CTBT). The project, which formally began February 28, 1998, and ended September 1, 2000, had three basic objectives: (1) Strategically install a three-component broadband digital seismic station in the WP-BC region to ensure the continuous recording of high-quality waveform data to meet the long-term needs of LLNL, UUSS, and other interested parties, including the international CTBT community. (2) Determine source mechanisms--to the extent that available source data and resources allowed--for comparative seismic characterization of stress release in mines versus earthquakes in the WP-BC study region. (3) Gather and report to LLNL local information on mine operations and associated seismicity, including ''ground truth'' for significant events. Following guidance from LLNL's Technical Representative, the focus of Objective 2 was changed slightly to place emphasis on three mining-related events that occurred in and near the study area after the original work plan had been made, thus posing new targets of opportunity. These included: a magnitude 3.8 shock that occurred

  6. A Preliminary Feasibility Study On Seismic Monitoring Of Polymer Flooding

    NASA Astrophysics Data System (ADS)

    Nguyen, P. K.; Park, C.; Lim, B.; Nam, M.

    2012-12-01

    Polymer flooding using water with soluble polymers is an enhanced oil recovery technique, which intends to maximize oil-recovery sweep efficiency by minimizing fingering effects and as a result creating a smooth flood front; polymer flooding decreases the flow rates within high permeability zone while enhances those of lower permeabilities. Understanding of fluid fronts and saturations is critical to not only optimizing polymer flooding but also monitoring the efficiency. Polymer flooding monitoring can be made in single well scale with high-resolution wireline logging, in inter-well scale with tomography, and in reservoir scale with surface survey. For reservoir scale monitoring, this study makes a preliminary feasibility study based on constructing rock physics models (RPMs), which can bridge variations in reservoir parameters to the changes in seismic responses. For constructing RPMs, we change reservoir parameters with consideration of polymer flooding to a reservoir. Time-lapse seismic data for corresponding RPMs are simulated using a time-domain staggered-finite-difference modeling with implementation of a boundary condition of conventional perfect match layer. Analysis on time-lapse seismic data with respect to the changes in fluid front and saturation can give an insight on feasibility of surface seismic survey to polymer flooding. Acknowledgements: This work was supported by the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Knowledge Economy (No. 2012T100201588). Myung Jin Nam was partially supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MEST) (No. 2011-0014684).

  7. ADVANCED WAVEFORM SIMULATION FOR SEISMIC MONITORING EVENTS

    SciTech Connect

    Helmberger, D; Tromp, J; Rodgers, A

    2007-07-16

    Comprehensive test ban monitoring in terms of location and discrimination has progressed significantly in recent years. However, the characterization of sources and the estimation of low yields remains a particular challenge. As the recent Korean shot demonstrated, we can probably expect to have a small set of teleseismic, far-regional and high-frequency regional data to analyze in estimating the yield of an event. Since stacking helps to bring signals out of the noise, it becomes useful to conduct comparable analyses on neighboring events, earthquakes in this case. If these auxiliary events have accurate moments and source descriptions, we have a means of directly comparing effective source strengths. Although we will rely on modeling codes, 1D, 2D, and 3D, we will also apply a broadband calibration procedure to use longer periods (P>5s) waveform data to calibrate short-period (P between .5 to 2 Hz) and high-frequency (P between 2 to 10 Hz) as path specify station corrections from well-known regional sources. We have expanded our basic Cut-and-Paste (CAP) methodology to include not only timing shifts but also amplitude (f) corrections at recording sites. The name of this method was derived from source inversions that allow timing shifts between 'waveform segments' (or cutting the seismogram up and re-assembling) to correct for crustal variation. For convenience, we will refer to these f-dependent refinements as CAP+ for (SP) and CAP++ for still higher frequency. These methods allow the retrieval of source parameters using only P-waveforms where radiation patterns are obvious as demonstrated in this report and are well suited for explosion P-wave data. The method is easily extended to all distances because it uses Green's function although there may be some changes required in t* to adjust for offsets between local vs. teleseismic distances. In short, we use a mixture of model-dependent and empirical corrections to tackle the path effects. Although we reply on the

  8. The Pollino 2012 seismic sequence: clues from continuous radon monitoring

    NASA Astrophysics Data System (ADS)

    Piersanti, Antonio; Cannelli, Valentina; Galli, Gianfranco

    2016-09-01

    The 2012 Pollino (Calabria, Italy) seismic sequence, culminating in the Mw 5.2 earthquake of 25 October 2012, is investigated, exploiting data collected during a long-term continuous radon monitoring experiment performed in the epicentral area from late 2011 to the end of 2014. We analyse data collected both using a phenomenological approach based on quantitative evidence and a purely numerical analysis including the following: (i) correlation and cross-correlation investigations; (ii) an original approach aimed at limiting the impact of meteorological parameters variations on the interpretation of measured radon levels; (iii) a change point analysis; (iv) the implementation of an original detection algorithm aimed at highlighting the connections between radon emission variations and major seismic events occurrence. Results from both approaches suggest that radon monitoring stations can be subject to massive site effects, especially regarding rainfall, making data interpretation harder. The availability of long-term continuous measurements is crucial to precisely assess those effects. Nevertheless, statistical analysis shows a viable approach for quantitatively relating radon emanation variations to seismic energy release. Although much work is still needed to make radon time series analysis a robust complement to traditional seismological tools, this work has identified a characteristic variation in radon exhalation during the preparation process of large earthquakes.

  9. Passive Seismic Monitoring for Rockfall at Yucca Mountain: Concept Tests

    SciTech Connect

    Cheng, J; Twilley, K; Murvosh, H; Tu, Y; Luke, B; Yfantis, A; Harris, D B

    2003-03-03

    For the purpose of proof-testing a system intended to remotely monitor rockfall inside a potential radioactive waste repository at Yucca Mountain, a system of seismic sub-arrays will be deployed and tested on the surface of the mountain. The goal is to identify and locate rockfall events remotely using automated data collecting and processing techniques. We install seismometers on the ground surface, generate seismic energy to simulate rockfall in underground space beneath the array, and interpret the surface response to discriminate and locate the event. Data will be analyzed using matched-field processing, a generalized beam forming method for localizing discrete signals. Software is being developed to facilitate the processing. To date, a three-component sub-array has been installed and successfully tested.

  10. Romanian Data Center: A modern way for seismic monitoring

    NASA Astrophysics Data System (ADS)

    Neagoe, Cristian; Marius Manea, Liviu; Ionescu, Constantin

    2014-05-01

    The main seismic survey of Romania is performed by the National Institute for Earth Physics (NIEP) which operates a real-time digital seismic network. The NIEP real-time network currently consists of 102 stations and two seismic arrays equipped with different high quality digitizers (Kinemetrics K2, Quanterra Q330, Quanterra Q330HR, PS6-26, Basalt), broadband and short period seismometers (CMG3ESP, CMG40T, KS2000, KS54000, KS2000, CMG3T,STS2, SH-1, S13, Mark l4c, Ranger, gs21, Mark l22) and acceleration sensors (Episensor Kinemetrics). The data are transmitted at the National Data Center (NDC) and Eforie Nord (EFOR) Seismic Observatory. EFOR is the back-up for the NDC and also a monitoring center for the Black Sea tsunami events. NIEP is a data acquisition node for the seismic network of Moldova (FDSN code MD) composed of five seismic stations. NIEP has installed in the northern part of Bulgaria eight seismic stations equipped with broadband sensors and Episensors and nine accelerometers (Episensors) installed in nine districts along the Danube River. All the data are acquired at NIEP for Early Warning System and for primary estimation of the earthquake parameters. The real-time acquisition (RT) and data exchange is done by Antelope software and Seedlink (from Seiscomp3). The real-time data communication is ensured by different types of transmission: GPRS, satellite, radio, Internet and a dedicated line provided by a governmental network. For data processing and analysis at the two data centers Antelope 5.2 TM is being used running on 3 workstations: one from a CentOS platform and two on MacOS. Also a Seiscomp3 server stands as back-up for Antelope 5.2 Both acquisition and analysis of seismic data systems produce information about local and global parameters of earthquakes. In addition, Antelope is used for manual processing (event association, calculation of magnitude, creating a database, sending seismic bulletins, calculation of PGA and PGV, etc.), generating

  11. Monitoring Klyuchevskoy group of volcanoes (Kamchatka) using seismic noise records

    NASA Astrophysics Data System (ADS)

    Gómez-García, Clara; Brenguier, Florent; Shapiro, Nikolai M.; Droznin, Dmitry V.; Droznina, Svetlana Y.; Chebrov, Victor N.; Gordeev, Evgenii I.

    2016-04-01

    In the last decade, extraction of Green functions from seismic ambient noise has been used extensive and efficiently in different contexts and scales: from imaging to monitoring the Earth's interior and from global to local scales. By using coda waves of noise cross-correlations to estimate travel time perturbations, we can assign changes in delay times to changes in the medium's velocity. Due to this technique attribute of continuous recording of the medium, it can accurately detect very small seismic velocity changes linked to small disturbances in volcano interiors. However, cross-correlation functions (CCF) do not necessary converge to media Green function: measurements of waveforms perturbations within a volcanic edifice are affected by the noise fluctuation. The Klyuchevskoy volcanic group, located above the edge of the Pacific Plate subducting beneath Kamchatka, is one of the most active clusters of volcanoes in the word. It is characterized by strongly localized volcanic tremor sources, which often dominate the recorded wavefield. To monitor and get measurements of temporal changes of these active volcanoes, we use coda waves of daily CCF from a total of 19 seismic stations from the seismic network operated by the Kamchatka Branch of the Geophysical Service (KBGS) of the Russian Academy of Sciences. Our study period goes from January 2009 to July 2013 in which two eruptions occurred: one from the Klyuchevskoy volcano (2009-2010) and the other from the Tolbachik volcano (2012-2013). After a quality checking of the records and testing different filters, we filter data in the frequency range 0.08 - 7 Hz and we use the Moving Window Cross Spectrum (MWCS) method to measure the relative time shifts. As both eruptions are characterized by emissions of seismic tremors, we avoid the choice of an arbitrary reference CCF: we compute velocity changes between all pairs of daily CCF. We retrieve a continuous velocity change time series for each station pair using a

  12. The current state of seismic monitoring in Switzerland

    NASA Astrophysics Data System (ADS)

    Clinton, J. F.; Haslinger, F.; Diehl, T.; Cauzzi, C.; Plenkers, K.; Kästli, P.; Fäh, D.; Wiemer, S.

    2013-12-01

    The Swiss Seismological Service at ETH Zurich (SED) operates both the national strong motion and broadband permanent seismic networks in Switzerland, as well as supporting local real-time densifications related to projects (such as geothermal explorations and major tunneling) and a mobile pool for national and international deployments related to research and aftershock studies. This submission provides an overview of the current status of network monitoring in Switzerland. A digital high gain network has been operating since 1974 and was upgraded to a continuously recording realtime modern 24 bit broadband network comprising 30 stations from 1999-2002, with station spacing averaging ~30km across the nation. Various improvements and densifications since then have raised the number of broadband sensors to 45 and added co-located strong motion sensors at 13 sites. A notable recent densification is in the NE of Switzerland, where the Swiss National Cooperative for the Disposal of Radioactive Waste (Nagra) have funded an additional 10 broadband stations (including 3 100-200m deep borehole short period stations) in order to reduce the earthquake detection threshold and increase location accuracy in regions that are identified as potential deep nuclear waste storage sites. A strong motion network has been maintained since 1990, comprising 70 12-16 bit triggered sensors located predominantly in free-field urban sites but also including arrays on dams. The free-field network is in the midst of an upgrade (2009-2018), with 30 new stations already installed from the eventual 100 new free-field 24-bit real-time continuous stations. A project has just begun to upgrade the Swiss broadband network, which will co-locate strong-motion sensors at existing broadband sites; assess and implement improvements of installation quality, e.g. by shallow post-hole installations rather than surface vaults; and potentially fill remaining gaps in station coverage. The seismic network has

  13. Integrated Reflection Seismic Monitoring and Reservoir Modeling for Geologic CO2 Sequestration

    SciTech Connect

    John Rogers

    2011-12-31

    The US DOE/NETL CCS MVA program funded a project with Fusion Petroleum Technologies Inc. (now SIGMA) to model the proof of concept of using sparse seismic data in the monitoring of CO{sub 2} injected into saline aquifers. The goal of the project was to develop and demonstrate an active source reflection seismic imaging strategy based on deployment of spatially sparse surface seismic arrays. The primary objective was to test the feasibility of sparse seismic array systems to monitor the CO{sub 2} plume migration injected into deep saline aquifers. The USDOE/RMOTC Teapot Dome (Wyoming) 3D seismic and reservoir data targeting the Crow Mountain formation was used as a realistic proxy to evaluate the feasibility of the proposed methodology. Though the RMOTC field has been well studied, the Crow Mountain as a saline aquifer has not been studied previously as a CO{sub 2} sequestration (storage) candidate reservoir. A full reprocessing of the seismic data from field tapes that included prestack time migration (PSTM) followed by prestack depth migration (PSDM) was performed. A baseline reservoir model was generated from the new imaging results that characterized the faults and horizon surfaces of the Crow Mountain reservoir. The 3D interpretation was integrated with the petrophysical data from available wells and incorporated into a geocellular model. The reservoir structure used in the geocellular model was developed using advanced inversion technologies including Fusion's ThinMAN{trademark} broadband spectral inversion. Seal failure risk was assessed using Fusion's proprietary GEOPRESS{trademark} pore pressure and fracture pressure prediction technology. CO{sub 2} injection was simulated into the Crow Mountain with a commercial reservoir simulator. Approximately 1.2MM tons of CO{sub 2} was simulated to be injected into the Crow Mountain reservoir over 30 years and subsequently let 'soak' in the reservoir for 970 years. The relatively small plume developed from this

  14. Monitoring Seasonal Changes in Permafrost Using Seismic Interferometry

    NASA Astrophysics Data System (ADS)

    James, S. R.; Knox, H. A.; Abbott, R. E.

    2015-12-01

    The effects of climate change in polar regions and their incorporation in global climate models has recently become an area of great interest. Permafrost holds entrapped greenhouse gases, e.g. CO2 and CH4, which are released to the atmosphere upon thawing, creating a positive feedback mechanism. Knowledge of seasonal changes in active layer thickness as well as long term degradation of permafrost is critical to the management of high latitude infrastructures, hazard mitigation, and increasing the accuracy of climate predictions. Methods for effectively imaging the spatial extent, depth, thickness, and discontinuous nature of permafrost over large areas are needed. Furthermore, continuous monitoring of permafrost over annual time scales would provide valuable insight into permafrost degradation. Seismic interferometry using ambient seismic noise has proven effective for recording velocity changes within the subsurface for a variety of applications, but has yet to be applied to permafrost studies. To this end, we deployed 7 Nanometrics Trillium posthole broadband seismometers within Poker Flat Research Range, located 30 miles north of Fairbanks, Alaska in a zone of discontinuous permafrost. Approximately 2 years worth of nearly continuous ambient noise data was collected. Using the python package MSNoise, relative changes in velocity were calculated. Results show high amounts of variability throughout the study period. General trends of negative relative velocity shifts can be seen between August and October followed by a positive relative velocity shift between November and February. Differences in relative velocity changes with both frequency and spatial location are also observed, suggesting this technique is sensitive to permafrost variation with depth and extent. Overall, short and long term changes in shallow subsurface velocity can be recovered using this method proposing seismic interferometry is a promising new technique for permafrost monitoring. Sandia

  15. Virtual Seismometer and Adjoint Methods for Induced Seismicity Monitoring

    NASA Astrophysics Data System (ADS)

    Morency, C.; Matzel, E.

    2014-12-01

    Induced seismicity is associated with subsurface fluid injection, and puts at risk efforts to develop geologic carbon sequestration and enhanced geothermal systems. We are developing methods to monitor the microseismically active zone so that we can identify faults at risk of slipping. We are using the Virtual Seismometer Method (VSM), which is an interferometric technique that is very sensitive to the source parameters (location, mechanism and magnitude) and to the earth structure in the source region. Given an ideal geometry, that is, when two quakes are roughly in line with a recording station, the correlation of their waveforms provide a precise estimate of the Green's function between them, modified by their source mechanisms. When measuring microseismicity, this geometry is rarely ideal and we need to account for variations in the geometry as well. In addition, we also investigate the adjoint method to calculate sensitivity kernels, which define the sensitivity of an observable to model parameters. Classically, adjoint tomography relies on the interaction between a forward waveform, from the source to the recording station, and a backpropagated waveform, from the recorded station to the source. By combining the two approaches we can focus on properties directly between induced micro events, and doing so, monitor the evolution of the seismicity and precisely image potential fault zones. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  16. Multichannel seismic/oceanographic/biological monitoring of the oceans

    NASA Astrophysics Data System (ADS)

    Hello, Y.; Leymarie, E.; Ogé, A.; Poteau, A.; Argentino, J.; Sukhovich, A.; Claustre, H.; Nolet, G.

    2011-12-01

    Delays in seismic P wave are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions. Free-drifting profiling floats that measure the temperature, salinity and current of the upper 2000 m of the ocean are used by physical oceanographers for continuous monitoring in the Argo program. Recently, seismologists developed the idea to use such floats in order to compensate for the lack of seismic delay observations, especially in the southern hemisphere. In project Globalseis, financed by a grant from the European Research Council (ERC), we have developed and tested a prototype of such a seismological sensor using an Apex float from Teledyne Webb Research, a Rafos hydrophone, and electronics developed in collaboration with Osean, a small engineering firm in France. `MERMAID', for `Mobile Earthquake Recorder in Marine Areas by Independent Divers' is approaching its final design and should become available off the shelf in 2012. In the meantime we initiated a collaboration between Globalseis and another ERC project, remOcean, for the acquisition of radiometric, bio-geochemical data and meteorological observations in addition to salinity and temperature (Bio-Argo program). In this collaboration of Geoazur and LOV (Laboratoire d'Océanologie de Villefranche sur mer), two laboratories located at the Observatory of Villefranche, we developed a multichannel acquisition hardware electronics called 'PAYLOAD' that allows commercial floats such as Apex (TWR) and Provor (NKE) to serve multiple observing missions simultaneously. Based on an algorithm using wavelet transforms PAYLOAD continuously analyzes acoustic signals to detect major seismic events and weather phenomena such rain, drizzle, open sea and ice during drift diving phase. The bio-geochemical and other parameters are recorded and analyzed during ascent

  17. Storey building early monitoring based on rapid seismic response analysis

    NASA Astrophysics Data System (ADS)

    Julius, Musa, Admiral; Sunardi, Bambang; Rudyanto, Ariska

    2016-05-01

    Within the last decade, advances in the acquisition, processing and transmission of data from seismic monitoring has contributed to the growth in the number structures instrumented with such systems. An equally important factor for such growth can be attributed to the demands by stakeholders to find rapid answers to important questions related to the functionality or state of "health" of structures during and immediately of a seismic events. Consequently, this study aims to monitor the storey building based on seismic response i. e. earthquake and tremor analysis at short time lapse using accelerographs data. This study used one of storey building (X) in Jakarta city that suffered the effects of Kebumen earthquake January 25th 2014, Pandeglang earthquake July 9th 2014, and Lebak earthquake November 8th 2014. Tremors used in this study are tremors after the three following earthquakes. Data processing used to determine peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), spectral acceleration (SA), spectral velocity (SV), spectral displacement (SD), A/V ratio, acceleration amplification and effective duration (te). Then determine the natural frequency (f0) and peak of H/V ratio using H/V ratio method.The earthquakes data processing result shows the value of peak ground motion, spectrum response, A/V ratio and acceleration amplification increases with height, while the value of the effective duration give a different viewpoint of building dynamic because duration of Kebumen earthquake shows the highest energy in the highest floor but Pandeglang and Lebak earthquake in the lowest floor. Then, tremors data processing result one month after each earthquakes shows the natural frequency of building in constant value. Increasing of peak ground motion, spectrum response, A/V ratio, acceleration amplification, then decrease of effective duration following the increase of building floors shows that the building construction supports the

  18. Crustal Seismic Anisotropy Produced by Rock Fabric Terranes in the Taiwan Central Range Deformational Orogen: Integrative Study Combining Rock Physics, Structural Geology, and Passive/Active-Source Seismology

    NASA Astrophysics Data System (ADS)

    Okaya, D. A.; Ross, Z.; Christensen, N. I.; Wu, F. T.; Byrne, T. B.

    2014-12-01

    The island of Taiwan is currently under construction due to the collision of the northwestern corner of the Philippine Sea plate and the embedded Luzon island arc with the larger continental Eurasian plate. This collision is responsible for the current growth of the Central Range that dominates the eastern half of the island. An international collaboration involving several USA and Taiwan universities and academic institutions was formed to study how the orogen evolves through time and to understand the role of a colliding island arc in mountain building. The project, Taiwan Integrated Geodynamics Research (TAIGER), was funded by NSF-Continental Dynamics and Taiwan National Science Council. The Central Range grows at one of the most rapid rates of uplift in the world, exposing metamorphic rocks that were once at least 10 km deep. The range offers unique opportunities for studies of crustal seismic anisotropy for two major reasons: (1) its geological makeup is conducive for producing crustal seismic anisotropy; that is, the rocks are highly foliated; and (2) a seismological data volume of significant breadth offers extensive coverage of sources and recording stations throughout the region. We carried out a crustal shear wave splitting study by data mining 3300 local earthquakes collected in the TAIGER 2009 sea-land experiment. We used an automated P and S wave arrival time picking method (Ross and Ben-Zion, 2014) applied to over 100,000 event-station pairs. These data were analyzed for shear-wave splitting using the MFAST automated package (Savage et al., 2010), producing 3300 quality shear wave split measurements. The splitting results were then station-averaged. The results show NNE to NE orientation trends that are consistent with regional cleavage strikes. Average crustal shear wave split time is 0.244 sec. These measurements are consistent with rock physics measurements of Central Range slate and metamorphic acoustic velocities. The splits exhibit orientations

  19. Crustal rifting and magmatic underplating in the Izu-Ogasawara (Bonin) intra-oceanic arc detected by active source seismic studies

    NASA Astrophysics Data System (ADS)

    Takahashi, N.; Kodaira, S.; Yamashita, M.; Miura, S.; Sato, T.; No, T.; Tatsumi, Y.; Kaneda, Y.

    2009-12-01

    Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has carried out seismic experiments using a multichannel reflection system and ocean bottom seismographs (OBSs) in the Izu-Ogasawara (Bonin)-Mariana (IBM) arc region since 2002 to understand growth process of continental crust. The source was an airgun array with a total capacity of 12,000 cubic inches and the OBSs as the receiver were deployed with an interval of 5 km for all seismic refraction experiments. As the results, we obtained crustal structures across the whole IBM arc with an interval of 50 km and detected the structural characteristics showing the crustal growth process. The IBM arc is one of typical oceanic island arc, which crustal growth started from subduction of an oceanic crust beneath the other oceanic crust. The arc crust has developed through repeatedly magmatic accretion from subduction slab and backarc opening. The volcanism has activated in Eocene, Oligocene, Miocene and Quaternary (e.g., Taylor, 1992), however, these detailed locations of past volcanic arc has been remained as one of unknown issues. In addition, a role of crustal rifting for the crustal growth has also been still unknown issue yet. Our seismic structures show three rows of past volcanic arc crusts except current arc. A rear arc and a forearc side have one and two, respectively. The first one, which was already reported by Kodaira et al. (2008), distributes in northern side from 27 N of the rear arc region. The second one, which develops in the forearc region next to the recent volcanic front, distributes in whole of the Izu-Ogasawara arc having crustal variation along arc direction. Ones of them sometimes have thicker crust than that beneath current volcanic front and no clear topographic high. Last one in the forearc connects to the Ogasawara Ridge. However, thickest crust is not always located beneath these volcanic arcs. The initial rifting region like the northern end of the Mariana Trough and the Sumisu

  20. The Feasibility of Monitoring Continuous Wave Sources with Seismic Arrays

    SciTech Connect

    Claassen, J.P.; Elbring, G.; Ladd, M.

    1999-03-15

    This paper identifies and explores the technical requirements and issues associated with remotely monitoring continuous wave (CW) sources with seismic arrays. Potential approaches to this monitoring problem will be suggested and partially evaluated to expose the monitoring challenges which arise when realistic local geologies and cultural noise sources are considered. The selective directionality and the adaptive noise cancellation properties of arrays are required to observe weak signals while suppressing a colored background punctuated with an unknown distribution of point and sometimes distributive sources. The array is also required to characterize the emitters and propagation environment so as to properly focus on the CW sources of interest while suppressing the remaining emitters. The proper application of arrays requires an appreciation of the complexity of propagation in a non-homogeneous earth. The heterogeneity often limits the available spatial coherence and therefore the size of the army. This adversely impacts the array gain and the array's ability to carefully resolve various emitters. Arrays must also contend with multipath induced by the source and the heterogeneous earth. If the array is to focus on an emitter and realize an enhancement in the signal to noise ratio, methods must be sought to coherently add the desired signal components while suppressing interference which may be correlated with the desired signal. The impact of these and other issues on army design and processing are described and discussed.

  1. Multichannel seismic/weather/Zoological monitoring of the oceans

    NASA Astrophysics Data System (ADS)

    Hello, Yann; Bonnieux, Sebastien; Sukovitch, Alexey; Argentino, Jean-Francois; Nolet, Guust

    2013-04-01

    Delays of seismic P waves are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions. Free-drifting profiling floats that measure the temperature, salinity and current of the upper 2000 m of the ocean are used by physical oceanographers for continuous monitoring in the Argo program. Recently, seismologists developed the idea to use such floats in order to compensate for the lack of seismic delay observations, especially in the southern hemisphere. In project Globalseis, financed by a grant from the European Research Council (ERC), we have built and tested a prototype of such a seismological sensor using an Apex float from Teledyne Webb Research, a Rafos hydrophone, and electronics developed in collaboration with Osean, a small engineering firm in France. `MERMAID', for `Mobile Earthquake Recorder in Marine Areas by Independent Divers' has concuded its final design stage and a fleet of 20 units is available off the shelf. Two of these floats have been deployed in the Mediterranean sea between Nice and the island of Corsica late 2012, others will be deployed in 2013, in the South Indian Ocean and near Galapagos in the Pacific. Analysis of the first data will allow us to sharpen the wavelet-based algorithm parameters used to discriminate P-waves from the continuous input signal. Ten significant events can be stored in internal memory during an average "parking depth" drift of 10 days at a chosen depth of up to 2 km. Events are classified by interest and when the memory is full, larger events replace minor events. At the end of the preprogrammed mission the float surface and transmit data (health logs and events) in Rudics mode by Iridium satellite network. A major event will force the float to ascent at surface and transmit in a short delay the corresponding recorded data as well as its GPS

  2. Borehole-to-tunnel seismic measurements for monitoring radioactive waste

    NASA Astrophysics Data System (ADS)

    Manukyan, Edgar; Maurer, Hansruedi; Marelli, Stefano; Greenhalgh, Stewart A.; Green, Alan A.

    2010-05-01

    Countries worldwide are seeking solutions for the permanent removal of high-level radioactive waste (HLRW) from the environment. A critical aspect of the disposal process is the need to be confident that the deposited waste is safely isolated from the biosphere. Seismic monitoring represents a potentially powerful option for non-intrusive monitoring. We conducted a series of seismic experiments in the Mont Terri underground rock laboratory, where a 1-m-diameter microtunnel simulates a HLRW repository downsized by a factor of ~2.5. The host rock at the laboratory is Opalinus clay. We had access to two water-filled boreholes, each approximately 25 m long (diameter 85 mm), with one inclined upwards and the other downwards. Both were oriented perpendicular to the microtunnel axis. Seismic signals were generated in the down-dipping borehole with a high frequency P-wave sparker source every 25 cm and received every 25 cm in the upward-dipping borehole on a multi-channel hydrophone chain. Additionally, the seismic waves were recorded on eight (100 Hz natural frequency) vertical-component geophones, mounted and distributed around the circumference of the microtunnel wall within the plane of the boreholes. The experiment was repeated with different material filling the microtunnel and under different physical conditions. So far, six experiments have been performed when the microtunnel was: a. air-filled with a dry excavation damage zone (EDZ), b. dry sand-filled with a dry EDZ, c. 50 % water-saturated sand-filled with partially water-saturated EDZ (experiments were conducted immediately after half water-saturation), d. water-saturated sand-filled with partially water-saturated EDZ (immediately after full water-saturation), e. water-saturated sand-filled with water-saturated EDZ (water was in the microtunnel for about 9.5 months), and f. water-saturated sand-filled and pressurized to 6 bars with water-saturated EDZ. The results of our seismic experiments yield several

  3. Seismic Monitoring Developments In The North-eastern Italy

    NASA Astrophysics Data System (ADS)

    Michelini, A.; Crs Team

    NE Italy is an area affected by moderate seismicity with large events (ML>5.0) occur- ring with return period shorter than 50 years. Recently, two main events occurred in Friuli (May6, 1976, ML=6.4) and western Slovenia (April 12, 1998, ML=5,6). There- fore, the seismological monitoring of the area is of extreme importance from the sci- entific and the social point of view. At present, the Istituto Nazionale di Oceanografia e Geofisica Sperimentale (OGS) is monitoring the area with a short period seismic network including 17 stations covering the Friuli-Venezia Giulia and the north-east of the Veneto region. Furthermore, in cooperation with the University of Trieste, it operates two broad-band stations sited in Trieste and Villanova Grotte (central Friuli). OGS has now planned to extend its sensing capabilities by implementing a new inte- grated network including both short period and broad-band seismic stations as well as GPS stations for measures of deformation. The network will include new and existing instrumentation and will cover the area from the Garda lake to the slovenian border. Three main guidelines have inspired the design of such network: - on-line acquisition: data acquisition should occur in nearly real-time at the cen- tral stations in Udine. To this purpose, various transmission technologies will be considered (e.g. radio, telephone lines, GSM and satellite). - data integration: all data should be merged in the same database and made avail- able to the users through a uniform interface, independently from their type and modality of acquisition. - open access: data should be made available in near real-time to the entire sci- entific community, accessing the central data base and, when possible, directly the remote stations. The implementation of such goals will guarantee the full integration with the other networks covering the area, in particular the Slovenia and Austria networks. To this purpose, an experimental transfrontier broad-band network

  4. Seismic Monitoring studies at Popocatepetl volcano, México

    NASA Astrophysics Data System (ADS)

    Reyes Pimentel, T. A.; Cárdenas-Soto, M.

    2013-05-01

    We present the analysis of seven months of continuous record (March-September, 2012) of the seismic monitoring of Popocatépetl volcano in four broad band stations (the maximum aperture is 12 km). The aim is to explore whether the seismic interferometry method provides complimentary information about the tectonic stress before eruptive stages. In that period of time several eruptive events have occurred. One of them was a subduction-related earthquake (March, 20, 2012, M=7.4) that produced an increase in the volcanic activity. On March 30 the volcano registered a train of 10 hours of exhalations and from March 11 to 29 a swarm of 15 volcanotectonic events. Another important event lasted from April 13 to June 3, in which around 276 hours of harmonic and spasmodic tremor were recorded. One of the biggest events was on May 11, a volcano emissions of around 4 km above the crater with incandescent fragments falling on the volcano slope. From March to September 90 volcanotectonic events were registered the biggest occurred on April 14 and July 23 with Mc=3.2 and 2.9 respectively. Also we analyze the volcano activity with the SSEM analysis, which can be related with regional tectonic earthquakes. We take advantage of seismic noise to get daily correlograms for each motion component (Z, R, T) by stacking 40s time windows. We observe that there are consecutive days for which it is not possible to obtain correlations between pairs of stations, probably caused by instrumental problems or variations in absolute time. Between the nearest stations, 4 km on average, we get consistent correlations, but not in the days of major volcanic activity. The similarity between the Z and R correlograms indicate an appropriate extraction of Rayleigh waves, while in the T component we have the Love wave. Over longer distances it is not possible to extract the dispersion properties; however, the loss of correlation prevails for those days of increased activity. It is important to mention that

  5. Seismic augmentation of acoustic monitoring of mortar fire

    NASA Astrophysics Data System (ADS)

    Anderson, Thomas S.

    2007-10-01

    The US Army Corps of Engineers Research and Development Center participated in a joint ARL-NATO TG-53 field experiment and data collect at Yuma Proving Ground, AZ in early November 2005. Seismic and acoustic signatures from both muzzle blasts and impacts of small arms fire and artillery were recorded using 7 seismic arrays and 3 acoustic arrays. Arrays comprised of 12 seismic and 12 acoustic sensors each were located from 700 m to 18 km from gun positions. Preliminary analysis of signatures attributed to 60mm, 81mm, 120 mm mortars recorded at a seismic-acoustic array 1.1 km from gun position are presented. Seismic and acoustic array f-k analysis is performed to detect and characterize the source signature. Horizontal seismic data are analyzed to determine efficacy of a seismic discriminant for mortar and artillery sources. Rotation of North and East seismic components to radial and transverse components relative to the source-receiver path provide maximum surface wave amplitude on the transverse component. Angles of rotation agree well with f-k analysis of both seismic and acoustic signals. The spectral energy of the rotated transverse surface wave is observable on the all caliber of mortars at a distance of 1.1 km and is a reliable source discriminant for mortar sources at this distance. In a step towards automation, travel time stencils using local seismic and acoustic velocities are applied to seismic data for analysis and determination of source characteristics.

  6. Seismic Monitoring of the Arctic region by the International Monitoring System CTBTO

    NASA Astrophysics Data System (ADS)

    Medinskaya, Tatiana

    2016-04-01

    The seismic activity of the Arctic region is less studied in terms of geophysical explorations because of its harsh climatic conditions and low density population. Nowadays increasing the importance of this area leads us to conduct researches in collaboration with relevant international and regional organizations. The International Monitoring System (IMS) network is setup by Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) as the key element of the CTBT verification regime providing data from 50 primary and 120 auxiliary seismic stations deployed all over the world. The aim of this study is to quantify the effective detection capability of the current state of IMS network in order to monitor the Arctic region and evaluate the accuracy of seismic event locations based on the Reviewed Event Bulletin (REB) issued by the CTBTO. A total of 3.928 earthquakes recorded by the IMS Network and reviewed by analysts at the International Data Centre (IDC) during the period from January 2009 to December 2015 at an area above 60°N surrounding the North Pole have been selected. The studied areas cover several tectonic provinces of the Eurasian Arctic, such as Fennoscandia, Eastern Siberia together with Iceland, Greenland, northern Canada and Alaska.

  7. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallares, V.; Ranero, C. R.

    2012-12-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  8. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallarès, V.; Ranero, C. R.

    2012-04-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  9. Evidence of post-seismic creep type deformations derived by tilt and acoustic emission monitoring of mining induced seismic events

    NASA Astrophysics Data System (ADS)

    Milev, Alexander; Share, Pieter-Ewald; Naoi, Makoto; Durrheim, Raymond; Yabe, Yasuo; Ogasawara, Hiroshi; Nakatani, Masao

    2015-04-01

    In this study we try to understand pre- and post-failure rock behavior associated with mining induced seismic events. This involves underground installation of various high precision instruments, including geophones, acoustic emission sensors, tilt- and strain-meters at a number of sites in deep level South African gold mines. The rate of tilt, strain and the seismic ground motion were analysed in order to understand the coseismic and aseismic deformation of the rocks. A good correspondence between the coseismic and the aseismic deformations was found. The rate of coseismic and aseismic tilt, as well as seismicity recorded by the mine seismic network, are approximately constant until the daily blasting time, which takes place from about 19:30 until shortly before 21:00. During the blasting time and the subsequent seismic events, the coseismic tilt and strain shows a rapid increase. Much of the aseismic deformation, however, occurs independently of the seismic events and blasting. In an attempt to distinguish between the different mechanisms of tilting two types of events were recognized. The "fast" seismic events characterized with sharp increase of the tilt during the seismic rupture and "slow" seismic events characterized by creep type post seismic deformations. Tilt behaviour before and after a seismic event was also analysed. The fact that no recognizable aftertilt was observed for more of the "fast" seismic events means that there is no gradual release of stress and an associated continuous strain rate change afterwards. It can therefore be concluded that a large seismic event causes a rapid change in the state of stress rather than a gradual change in the strain rate During the monitoring period a seismic event with MW 2.2 occurred in the vicinity of the instrumented site. This event was recorded by both the CSIR integrated monitoring system and JAGUARS acoustic emission network. More than 21,000 AE aftershocks were located in the first 150 hours after the

  10. Seismic monitoring instrumentation needs of a building owner and the solution - A cooperative effort

    USGS Publications Warehouse

    Celebi, M.; Sanli, A.; Sinclair, M.; Gallant, S.; Radulescu, D.; ,

    2003-01-01

    A specific case whereby the owner of a building, in collaboration with another federal agency with expertise in seismic monitoring of buildings, private consulting engineers, and a supplier, facilitated development of a seismic monitoring system for a 24-story building in San Francisco, California. The unique aspects of this monitoring systems include: the monitoring system must relate to rapid assessment of the building following an earthquake and the monitoring system must deliver the data in relatively short time, if not in real-time. The system has the standard recording capability at the site server PC. It has the capability to calculate select number of drift ratios, specific to the building.

  11. Microearthquake monitoring and seismic imaging at The Geysers

    SciTech Connect

    Zucca, J.J.; Hutchings, L.; Bonner, B.; Kasameyer, P.; Majer, E.L.; Peterson, J.; Romero, A.; Kirkpatrick, A.

    1994-06-01

    We are monitoring two high-frequency, high-resolution microearthquake networks at The Geysers. The first network consists of 16 stations and is located in the northwest portion of the Geysers. This array is in an area that is representative of a high-temperature, deep, reservoir environment. The second network consists of 13 stations located in the southeast Geysers around the location of the cooperative injection experiment. We are using the data from the networks to compute velocity and attenuation images and earthquake parameters such as precise location and rate and manner of energy release. Our goal is to evaluate the use of this information to manage steam release from geothermal reservoirs. We are supporting this effort with laboratory measurements of velocity and attenuation on Geysers core samples under varying degrees of saturation to help us better interpret our seismic images. To date we find that microearthquake activity follows injection activity, and the dry, low-pressure portions of the reservoir are characterized by low velocity and high attenuation.

  12. Continuous, Large-Scale Processing of Seismic Archives for High-Resolution Monitoring of Seismic Activity and Seismogenic Properties

    NASA Astrophysics Data System (ADS)

    Waldhauser, F.; Schaff, D. P.

    2012-12-01

    Archives of digital seismic data recorded by seismometer networks around the world have grown tremendously over the last several decades helped by the deployment of seismic stations and their continued operation within the framework of monitoring earthquake activity and verification of the Nuclear Test-Ban Treaty. We show results from our continuing effort in developing efficient waveform cross-correlation and double-difference analysis methods for the large-scale processing of regional and global seismic archives to improve existing earthquake parameter estimates, detect seismic events with magnitudes below current detection thresholds, and improve real-time monitoring procedures. We demonstrate the performance of these algorithms as applied to the 28-year long seismic archive of the Northern California Seismic Network. The tools enable the computation of periodic updates of a high-resolution earthquake catalog of currently over 500,000 earthquakes using simultaneous double-difference inversions, achieving up to three orders of magnitude resolution improvement over existing hypocenter locations. This catalog, together with associated metadata, form the underlying relational database for a real-time double-difference scheme, DDRT, which rapidly computes high-precision correlation times and hypocenter locations of new events with respect to the background archive (http://ddrt.ldeo.columbia.edu). The DDRT system facilitates near-real-time seismicity analysis, including the ability to search at an unprecedented resolution for spatio-temporal changes in seismogenic properties. In areas with continuously recording stations, we show that a detector built around a scaled cross-correlation function can lower the detection threshold by one magnitude unit compared to the STA/LTA based detector employed at the network. This leads to increased event density, which in turn pushes the resolution capability of our location algorithms. On a global scale, we are currently building

  13. Seismic monitoring of a flow test in the Salton Sea Geothermal Field

    SciTech Connect

    Jarpe, S.P.; Kasameyer, P.W.; Johnston, C.

    1989-06-01

    The purpose of this seismic monitoring project was to characterize in detail the micro-seismic activity related to the flow-injection test in the Salton Sea Geothermal Field. Our goal was to determine if any sources of seismic energy related to the test were observable at the surface, using both conventional seismic network techniques and relatively newer array techniques. These methods allowed us to detect and locate both impulsive microearthquakes and continuous sources of seismic energy. Our network, which was sensitive enough to be triggered by magnitude 0.0 or larger events, found no impulsive microearthquakes in the vicinity of the flow test in the 8 month period before the test and only one event during the flow test. We have observed some continuous seismic noise sources that may be attributed to the flow test. 4 refs., 4 figs.

  14. SeisRockHT - Seismic Rockfall Monitoring in the Hohe Tauern region

    NASA Astrophysics Data System (ADS)

    Binder, Daniel; Hartmeyer, Ingo; Keuschnig, Markus; Mertl, Stefan; Lenhardt, Wolfgang

    2016-04-01

    SeisRockHT focuses on open hardware and free software applied for scientific long-term monitoring strategies in harsh environments. In detail, SeisRockHT aims at the establishment of two seismic networks to quantitatively observe seismicity and rockfall events at high alpine north faces. Due to the rare character of rockfall events, a continuous and long-term observation strategy is targeted. The long-term perspective is assured through the project partner of the Austrian seismic service who will include SeisRockHT networks when the project is completed. Two study sites were selected for monitoring: the Kitzsteinhorn and the Hohe Sonnblick exhibiting two different scales of monitoring networks. The smaller scaled Kitzsteinhorn investigation site is closely related to bedrock permafrost processes, whereas the larger-scaled Sonnblick investigation site aims a classic alpine north face. SeisRockHT will develop a suite of optimum methods for characterization, detection and localization of the seismic events recorded at the two sites. Beside analysis of discrete seismic events, ambient seismic noise analysis promises a closer insight into rockfall precursory seismic characteristics.Based on the high quality complementary data delivered by already established long-term monitoring projects at the two sites, potential rockfall triggers will be suggested.

  15. Seismicity within the Irpinia Fault System As Monitored By Isnet (Irpinia Seismic Network) and Its Possible Relation with Fluid Storage

    NASA Astrophysics Data System (ADS)

    Festa, G.; Zollo, A.; Amoroso, O.; Ascione, A.; Colombelli, S.; Elia, L.; Emolo, A.; Martino, C.; Mazzoli, S.; Orefice, A.; Russo, G.

    2014-12-01

    ISNet (http://isnet.fisica.unina.it) is deployed in Southern Apennines along the active fault system responsible for the 1980, M 6.9 Irpinia earthquake. ISNet consists of 32 seismic stations equipped with both strong motion and velocimetric instruments (either broadband or short-period), with the aim of capture a broad set of seismic signals, from ambient noise to strong motion. Real time and near real time procedures run at ISNet with the goal of monitoring the seismicity, check possible space-time anomalies, detect seismic sequences and launch an earthquake early warning in the case of potential significant ground shaking in the area. To understand the role of fluids on the seismicity of the area, we investigated velocity and attenuation models. The former is built from accurate cross-correlation picking and S wave detection based onto polarization analysis. Joint inversion of both P and S arrival times is then based on a linearized multi-scale tomographic approach. Attenuation is instead obtained from inversion of displacement spectra, deconvolving for the source effect. High VP/VS and QS/QP >1 were found within a ~15 km wide rock volume where intense microseismicity is located. This indicates that concentration of seismicity is possibly controlled by high pore fluid pressure. This earthquake reservoir may come from a positive feedback between the seismic pumping that controls the fluid transmission through the fractured damage zone and the low permeability of cross fault barrier, increasing the fluid pore pressure within the fault bounded block. In this picture, sequences mostly occur at the base of this fluid rich layer. They show an anomalous pattern in the earthquake occurrence per magnitude classes; main events evolve with a complex source kinematics, as obtained from backprojection of apparent source time functions, indicating possible directivity effects. In this area sequences might be the key for understanding the transition between the deep

  16. Seismic Monitoring of Ice Generated Events at the Bering Glacier

    NASA Astrophysics Data System (ADS)

    Fitzgerald, K.; Richardson, J.; Pennington, W.

    2008-12-01

    The Bering Glacier, located in southeast Alaska, is the largest glacier in North America with a surface area of approximately 5,175 square kilometers. It extends from its source in the Bagley Icefield to its terminus in tidal Vitus Lake, which drains into the Gulf of Alaska. It is known that the glacier progresses downhill through the mechanisms of plastic crystal deformation and basal sliding. However, the basal processes which take place tens to hundreds of meters below the surface are not well understood, except through the study of sub- glacial landforms and passive seismology. Additionally, the sub-glacial processes enabling the surges, which occur approximately every two decades, are poorly understood. Two summer field campaigns in 2007 and 2008 were designed to investigate this process near the terminus of the glacier. During the summer of 2007, a field experiment at the Bering Glacier was conducted using a sparse array of L-22 short period sensors to monitor ice-related events. The array was in place for slightly over a week in August and consisted of five stations centered about the final turn of the glacier west of the Grindle Hills. Many events were observed, but due to the large distance between stations and the highly attenuating surface ice, few events were large enough to be recorded on sufficient stations to be accurately located and described. During August 2008, six stations were deployed for a similar length of time, but with a closer spacing. With this improved array, events were located and described more accurately, leading to additional conclusions about the surface, interior, and sub-glacial ice processes producing seismic signals. While the glacier was not surging during the experiment, this study may provide information on the non-surging, sub-glacial base level activity. It is generally expected that another surge will take place within a few years, and baseline studies such as this may assist in understanding the nature of surges.

  17. Continued seismic monitoring of the Geysers, California geothermal area

    SciTech Connect

    Ludwin, R.S.; Bufe, C.G.

    1980-01-01

    Probable effects of geothermal development on seismicity at the Geysers are shown by the spatial coherence of decreases in gravity and pressure with maximum geodetic deformation and seismic moment sum along a line through the most developed area of the geothermal field. Increases in the mean number of events per day and in the magnitude of largest annual event correlate with increases in steam production. The two largest earthquakes in the steam field occurred near the two injection wells most distant from production wells, and large events (M/sub c greater than or equal to 2.5) occurred most frequently during months of peak injection. Spatial seismic clusters in proximity to injection wells have occurred soon after injection began. Preliminary data also indicate an increase in seismicity in a previously aseismic area near plant 15 following the beginning of power production at that plant in 1979.

  18. SEISMIC DATA FOR NUCLEAR EXPLOSION MONITORING IN THE ARABIAN PENINSULA

    SciTech Connect

    Rodgers, A; Al-Amri, A

    2004-07-08

    We report results from the third and final year of our project (ROA0101-35) to collect seismic event and waveform data recorded in and around the Arabian Peninsula. This effort involves several elements. We are working with King Abdulaziz City for Science and Technology to collect data from the Saudi National Seismic Network, that consists of 38 digital three-component stations (27 broadband and 11 short-period). We have an ongoing collaboration with the Kuwait Institute for Scientific Research, which runs the eight station Kuwait National Seismic Network. We installed two temporary broadband stations in the United Arab Emirates (funded by NNSA NA-24 Office of Non-Proliferation & International Security). In this paper we present a summary of data collected under these efforts including integration of the raw data into LLNL's Seismic Research Database and preliminary analysis of souce parameters and earth structure.

  19. Development of real time monitor system displaying seismic waveform data observed at seafloor seismic network, DONET, for disaster management information

    NASA Astrophysics Data System (ADS)

    Horikawa, H.; Takaesu, M.; Sueki, K.; Takahashi, N.; Sonoda, A.; Miura, S.; Tsuboi, S.

    2014-12-01

    Mega-thrust earthquakes are anticipated to occur in the Nankai Trough in southwest Japan. In the source areas, we have deployed seafloor seismic network, DONET (Dense Ocean-floor Network System for Earthquake and Tsunamis), in 2010 in order to monitor seismicity, crustal deformations, and tsunamis. DONET system consists of totally 20 stations, which is composed of six kinds of sensors, including strong-motion seismometers and quartz pressure gauges. Those stations are densely distributed with an average spatial interval of 15-20 km and cover near the trench axis to coastal areas. Observed data are transferred to a land station through a fiber-optical cable and then to JAMSTEC (Japan Agency for Marine-Earth Science and Technology) data management center through a private network in real time. After 2011 off the Pacific coast of Tohoku Earthquake, each local government close to Nankai Trough try to plan disaster prevention scheme. JAMSTEC will disseminate DONET data combined with research accomplishment so that they will be widely recognized as important earthquake information. In order to open DONET data observed for research to local government, we have developed a web application system, REIS (Real-time Earthquake Information System). REIS is providing seismic waveform data to some local governments close to Nankai Trough as a pilot study. As soon as operation of DONET is ready, REIS will start full-scale operation. REIS can display seismic waveform data of DONET in real-time, users can select strong motion and pressure data, and configure the options of trace view arrangement, time scale, and amplitude. In addition to real-time monitoring, REIS can display past seismic waveform data and show earthquake epicenters on the map. In this presentation, we briefly introduce DONET system and then show our web application system. We also discuss our future plans for further developments of REIS.

  20. Seismic monitoring of the Séchilienne Rockslide (French Alps): analysis of seismic signals and their correlation with rainfalls

    NASA Astrophysics Data System (ADS)

    Helmstetter, Agnès.; Garambois, Stéphane; Kasperski, Johan; Duranthon, Jean-Paul; Pothérat, Pierre

    2010-05-01

    In the French Alps, Séchilienne rockslide is one of the natural phenomena presenting the highest risk in terms of socio-economical outcomes. This rock slide has been officially recognized as active for a few decades, and has been instrumented since 1985 for surveillance purposes. The current very active volume of this rockslide is roughly estimated to be up to 3 millions m3, located on the border of a slowly moving mass reaching 50 to 100 millions m3. The velocity of the most active zone has reached 1.4 m/yr in 2008, about twice the value of 2000. To assess the potential of seismology to supplement the current monitoring system, presently based on displacements measurements, a seismic network was installed in May 2007. It consists in three seismological stations deployed as antennas together with 37 velocimeters. It was installed thanks to the OMIV French national Observatory on landslides. Besides its main role in the monitoring of the seismic activity within the landslide, such network also aims to assess potential seismic site effects in case of earthquakes. Finally, it could also be useful to detect and characterize possible seismic velocity changes over time, by using noise correlation methods which require large observation periods. The seismological network has now recorded several thousands events, mostly due to rockfalls, but also hundreds of local (within the landslide) and regional earthquakes. We show here that most part of the recorded events can be distinguished and classified using their signal characteristics (frequency, duration). Some of the events, which were generated by rock falls, were also recorded by a camera facing the landslide for large volume studies. Unfortunately the acquired images are presently unable to provide the crucial information on fallen volumes, what prevents any calibration attempt between seismic energy and rock fall volume. We also found that rock falls and micro-seismicity, which occur in burst of activity, were weakly

  1. Monitoring seismic velocity changes caused by the 2014 Northern Aegean earthquake using continuous ambient noise records

    NASA Astrophysics Data System (ADS)

    Evangelidis, Christos; Daskalakis, Emmanouil; Tsogka, Chrysoula

    2016-04-01

    The 24 May 2014 Northern Aegean earthquake (6.9 Mw), an event on the Northern Aegean Trough (NAT), ruptured on two different fault segments with a total ruptured length of ~100 km. For the second delayed segment, rupture propagated eastward from the hypocenter for ˜65 km with a supershear velocity (5.5 km/s). Low-aftershock seismicity on the supershear segment implies a simple and linear fault geometry there. An effort to monitor temporal seismic velocity changes across the ruptured area of the Northern Aegean earthquake is underway. In recent years, neighboring seismic broadband stations near active faults have been successfully used to detect such changes. The crosscorrelation functions (CCF) of ambient noise records between stations yields the corresponding traveltimes for those inter-station paths. Moreover, the auto-correlation functions (ACF) at each station produce the seismic responce for a coincident source and receiver position. Possible temporal changes of the measured traveltimes from CCFs and ACFs correspond to seismic velocity changes. Initially, we investigate the characteristics and sources of the ambient seismic noise as recorded at permanent seismic stations installed around NAT at the surrounding islands and in mainland Greece and Turkey. The microseismic noise levels show a clear seasonal variation at all stations. The noise levels across the double frequency band (DF; period range 4-8 s) reflect the local sea-weather conditions within a range of a few hundred kilometers. Three years of continuous seismic records framing the main shock have been analysed from ~15 stations within a radius of 100 km from the epicentre. We observe a clear decrease of seismic velocities most likely corresponding to the co-seismic shaking. The spatial variation of this velocity drop is imaged from all inter-station paths that correspond to CCF measurements and for station sites that correspond to ACF measurements. Thus, we explore a possible correlation between co-seismic

  2. Monitoring El Hierro submarine volcanic eruption events with a submarine seismic array

    NASA Astrophysics Data System (ADS)

    Jurado, Maria Jose; Molino, Erik; Lopez, Carmen

    2013-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2012 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. From the beginning of the eruption a geophone string was installed less than 2 km away from the new volcano, next to La Restinga village shore, to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. The analysis of the dataset using spectral techniques allows the characterization of the different phases of the eruption and the study of its dynamics. The correlation of the data analysis results with the observed sea surface activity (ash and lava emission and degassing) and also with the seismic activity recorded by the IGN field seismic monitoring system, allows the identification of different stages suggesting the existence of different signal sources during the volcanic eruption and also the posteruptive record of the degassing activity. The study shows that the high frequency capability of the geophone array allow the study of important features that cannot be registered by the standard seismic stations. The accumulative spectral amplitude show features related to eruptive changes.

  3. Comprehensive Nuclear-Test-Ban Treaty seismic monitoring: 2012 USNAS report and recent explosions, earthquakes, and other seismic sources

    SciTech Connect

    Richards, Paul G.

    2014-05-09

    A comprehensive ban on nuclear explosive testing is briefly characterized as an arms control initiative related to the Non-Proliferation Treaty. The work of monitoring for nuclear explosions uses several technologies of which the most important is seismology-a physics discipline that draws upon extensive and ever-growing assets to monitor for earthquakes and other ground-motion phenomena as well as for explosions. This paper outlines the basic methods of seismic monitoring within that wider context, and lists web-based and other resources for learning details. It also summarizes the main conclusions, concerning capability to monitor for test-ban treaty compliance, contained in a major study published in March 2012 by the US National Academy of Sciences.

  4. Comprehensive Nuclear-Test-Ban Treaty seismic monitoring: 2012 USNAS report and recent explosions, earthquakes, and other seismic sources

    NASA Astrophysics Data System (ADS)

    Richards, Paul G.

    2014-05-01

    A comprehensive ban on nuclear explosive testing is briefly characterized as an arms control initiative related to the Non-Proliferation Treaty. The work of monitoring for nuclear explosions uses several technologies of which the most important is seismology-a physics discipline that draws upon extensive and ever-growing assets to monitor for earthquakes and other ground-motion phenomena as well as for explosions. This paper outlines the basic methods of seismic monitoring within that wider context, and lists web-based and other resources for learning details. It also summarizes the main conclusions, concerning capability to monitor for test-ban treaty compliance, contained in a major study published in March 2012 by the US National Academy of Sciences.

  5. GFZ Wireless Seismic Array (GFZ-WISE), a Wireless Mesh Network of Seismic Sensors: New Perspectives for Seismic Noise Array Investigations and Site Monitoring

    PubMed Central

    Picozzi, Matteo; Milkereit, Claus; Parolai, Stefano; Jaeckel, Karl-Heinz; Veit, Ingo; Fischer, Joachim; Zschau, Jochen

    2010-01-01

    Over the last few years, the analysis of seismic noise recorded by two dimensional arrays has been confirmed to be capable of deriving the subsoil shear-wave velocity structure down to several hundred meters depth. In fact, using just a few minutes of seismic noise recordings and combining this with the well known horizontal-to-vertical method, it has also been shown that it is possible to investigate the average one dimensional velocity structure below an array of stations in urban areas with a sufficient resolution to depths that would be prohibitive with active source array surveys, while in addition reducing the number of boreholes required to be drilled for site-effect analysis. However, the high cost of standard seismological instrumentation limits the number of sensors generally available for two-dimensional array measurements (i.e., of the order of 10), limiting the resolution in the estimated shear-wave velocity profiles. Therefore, new themes in site-effect estimation research by two-dimensional arrays involve the development and application of low-cost instrumentation, which potentially allows the performance of dense-array measurements, and the development of dedicated signal-analysis procedures for rapid and robust estimation of shear-wave velocity profiles. In this work, we present novel low-cost wireless instrumentation for dense two-dimensional ambient seismic noise array measurements that allows the real–time analysis of the surface-wavefield and the rapid estimation of the local shear-wave velocity structure for site response studies. We first introduce the general philosophy of the new system, as well as the hardware and software that forms the novel instrument, which we have tested in laboratory and field studies. PMID:22319298

  6. GFZ wireless seismic array (GFZ-WISE), a wireless mesh network of seismic sensors: new perspectives for seismic noise array investigations and site monitoring.

    PubMed

    Picozzi, Matteo; Milkereit, Claus; Parolai, Stefano; Jaeckel, Karl-Heinz; Veit, Ingo; Fischer, Joachim; Zschau, Jochen

    2010-01-01

    Over the last few years, the analysis of seismic noise recorded by two dimensional arrays has been confirmed to be capable of deriving the subsoil shear-wave velocity structure down to several hundred meters depth. In fact, using just a few minutes of seismic noise recordings and combining this with the well known horizontal-to-vertical method, it has also been shown that it is possible to investigate the average one dimensional velocity structure below an array of stations in urban areas with a sufficient resolution to depths that would be prohibitive with active source array surveys, while in addition reducing the number of boreholes required to be drilled for site-effect analysis. However, the high cost of standard seismological instrumentation limits the number of sensors generally available for two-dimensional array measurements (i.e., of the order of 10), limiting the resolution in the estimated shear-wave velocity profiles. Therefore, new themes in site-effect estimation research by two-dimensional arrays involve the development and application of low-cost instrumentation, which potentially allows the performance of dense-array measurements, and the development of dedicated signal-analysis procedures for rapid and robust estimation of shear-wave velocity profiles. In this work, we present novel low-cost wireless instrumentation for dense two-dimensional ambient seismic noise array measurements that allows the real-time analysis of the surface-wavefield and the rapid estimation of the local shear-wave velocity structure for site response studies. We first introduce the general philosophy of the new system, as well as the hardware and software that forms the novel instrument, which we have tested in laboratory and field studies.

  7. Microseismic Monitoring Using Surface and Borehole Seismic Stations in an Oil Field, North Oman

    NASA Astrophysics Data System (ADS)

    El-Hussain, I.; Al-Hashmi, S.; Al-Shijbi, Y.; Al-Saifi, M.; Al-Toubi, K.; Al-Lazki, A.; Al-Kindy, F.

    2009-05-01

    Five shallow borehole seismic stations were installed to monitor microearthquake activities in a carbonate oil field in northern Oman since 1999. This shallow network of seismic station operated continuously until 2002 after which intermittent seismic recording took place due to lack of maintenance and failure of some stations. The objectives of the study are to determine the microseismic parameters in the oil field and to determine the spatial and temporal distribution of these events to evaluate possible triggering mechanism. Well over 400 microearthquakes per year were recorded in the first three years of operation and after that the level of seismic recording fell to less than 200 microearthquakes per year due to failure of some stations. In March 2008, temporary seismic experiment consisting of five near surface seismic stations were installed in the oil field to augment the shallow network station and to evaluate surface installment of seismic instrument to monitor microseismic activities. It has been recognized that microearthquakes data such as size, spatial, and temporal distribution provide information on the pressure waves initiated by either production of or injection of fluids into reservoirs. A total of 44 local microearthquake events were analyzed and located during the temporary seismic stations deployment using a non-linear location software that allows the use of variable accurate velocity model of the subsurface. The events location is confined to oil field reservoir boundary during the recording period and more events occurring at shallow depth. The correlation coefficient between gas production and number of events is the higher compared with the oil production or water injection. The focal plane solution for the largest event in the sequence indicates normal faulting with extensional stress consistent with the existing mapped normal faults in the oil field. Microseismic signal clearly detected by the collocated sensors of the near surface

  8. 5 years of continuous seismic monitoring of snowmelt cycles in a Pyrenean valley

    NASA Astrophysics Data System (ADS)

    Diaz, Jordi; Sánchez-Pastor, Pilar; Gallart, Josep

    2016-04-01

    In recent years the analysis of background seismic noise variations in the proximity of river channels has revealed as a useful tool to monitor river flow, even for modest discharges. We will focus here in the application of this methodology to study the snowmelt cycle in an Pyrenean valley during the last 5 years, using data from the seismic geophysical station located inside the Canfranc Underground Laboratory (Central Pyrenees). Diaz et al. (2014) first identified in the seismic data the signature of river flow increases associated to snowmelt episodes in the catchment area of the Aragon River, based on the marked correlation between the seismic energy variations in the 2-8 Hz frequency band and the estimated variations in water resources from snowfall. The analysis of seismic data during the snowmelt periods allows to identify a clear 24h cycle, with energy increasing from about 14:00 GMT, remaining at a relatively high level for 12 hours and then smoothly vanishing. The spectrogram reveals richer information, as clear variations in the frequency content can be detected during the time intervals in which the amplitude of the seismic signal remains constant. The data available so far allow to compare the evolution of snowmelt in five seasons with very different hydrological behavior. The 2011 and 2012 seasons have been dry, with snow volumes 30-50 % beneath the average values, while the 2013, 2014 and in particular the 2015 seasons have been largely above the mean. Those variations are reflected in the seismic data, which allow to monitor the time occurrence of the main snowmelt stages for each season and to estimate the intensity of the different snowmelt episodes. Therefore, seismic data can be useful for long term monitoring of snowmelt in Alpine-style mountains.

  9. Dynamic seismic moment tensor creation for the Antelope Environmental Monitoring System

    NASA Astrophysics Data System (ADS)

    Newman, R. L.; Reyes, J. C.; van den Hazel, G.; Vernon, F. L.

    2011-12-01

    The native creation and display of seismic moment tensors, including the 'beachball' representation of the double-couple mechanism, have been missing in the popular BRTT Antelope Environmental Monitoring System that is used for seismic network and event monitoring. The seismic moment tensor inversion software package written by Dreger (2003) and updated by Minson & Dreger (2008) has been rewritten using a combination of the Python interface to Antelope (Lindquist et al., 2008) and various native Python packages, including NumPy, MatPlotLib and ObsPy (Beyreuther et al., 2010). The new moment tensor application ('dbmoment') uses the community standard Center for Seismic Studies (CSS) 3.0 schema, and can augment any real time earthquake monitoring system that uses the schema for post-event creation of moment tensor solutions. Rewriting the original code base from a combination of configuration scripts, Numerical Recipes for C, Seismic Analysis Code (SAC), the Fortran FKRPROG package (Saikia, 1994), and various intermediary files in ASCII and binary formats greatly simplifies installation, upgrading, and deployment of the software. All configuration files have been converted and condensed into BRTT parameter files and CSS schema extensions. The code has been added to the Github hosted open-source contributed code repository for the Antelope Environmental Monitoring System.

  10. Towards Quantification of Glacier Dynamic Ice Loss through Passive Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Köhler, A.; Nuth, C.; Weidle, C.; Schweitzer, J.; Kohler, J.; Buscaino, G.

    2015-12-01

    Global glaciers and ice caps loose mass through calving, while existing models are currently not equipped to realistically predict dynamic ice loss. This is mainly because long-term continuous calving records, that would help to better understand fine scale processes and key climatic-dynamic feedbacks between calving, climate, terminus evolution and marine conditions, do not exist. Combined passive seismic/acoustic strategies are the only technique able to capture rapid calving events continuously, independent of daylight or meteorological conditions. We have produced such a continuous calving record for Kronebreen, a tidewater glacier in Svalbard, using data from permanent seismic stations between 2001 and 2014. However, currently no method has been established in cryo-seismology to quantify the calving ice loss directly from seismic data. Independent calibration data is required to derive 1) a realistic estimation of the dynamic ice loss unobserved due to seismic noise and 2) a robust scaling of seismic calving signals to ice volumes. Here, we analyze the seismic calving record at Kronebreen and independent calving data in a first attempt to quantify ice loss directly from seismic records. We make use of a) calving flux data with weekly to monthly resolution obtained from satellite remote sensing and GPS data between 2007 and 2013, and b) direct, visual calving observations in two weeks in 2009 and 2010. Furthermore, the magnitude-scaling property of seismic calving events is analyzed. We derive and discuss an empirical relation between seismic calving events and calving flux which for the first time allows to estimate a time series of calving volumes more than one decade back in time. Improving our model requires to incorporate more precise, high-resolution calibration data. A new field campaign will combine innovative, multi-disciplinary monitoring techniques to measure calving ice volumes and dynamic ice-ocean interactions simultaneously with terrestrial laser

  11. Passive seismic monitoring studies at Tiris geothermal field in East Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Jaya, Makky; Jousset, Philippe; Deon, Fiorenza; Gassner, Alexandra; Putriatni, Dewi; Supoyo, Supoyo; Suprianto, Agus; Putra, Tri; Erbas, Kemal

    2013-04-01

    The Tiris geothermal field (TGF) is indicated by the presence of two sets of surface warm springs located within the proximity of two volcanoes: Mt. Lamongan and Mt. Argopuro. Preliminary assessment of TGF in terms of petrology of the volcanic rock and geochemistry of springs has been studied by Deon et al. (2012). The combination of petrology and geochemistry studies suggests: 1) the relation between sea water and the origin of warm springs and 2) the existence of a concealed layer responsible for capturing H2S gas which, in turn, accounts to the observed HCO3- excess of the springs. In order to support hypotheses resulting from those petrology and geochemistry studies, two passive seismic field experiments have been deployed successively. The first small-scale seismic noise study in 2011 was carried out by setting up 5 geophones for 5-days monitoring positioned around Mt. Lamongan. The second larger-scale passive seismic study has been performed since October 2012 setting up 16 short period stations and 4 broad-band stations around TGF for 6 months monitoring period. The goal of preliminary seismic noise test in 2011 was to identify pre-dominant noise characteristics in the area, while passive seismic monitoring in 2012 attempts to reveal the underground geologic structure of TGF derived from seismic properties. We report the set-up of both experiments and describe first result of seismic noise analysis and preliminary monitoring analysis. References Deon, F.; Moeck, I.; Scheytt, T.; Jaya, M.S. (2012): Preliminary assessment of the geothermal system of the Tiris colcanic area, East Java, Indonesia. 74th EAGE Conference & Exhibition (Copenhagen, Denmark 2012).

  12. Seismic monitoring of heavy oil reservoirs: Rock physics and finite element modelling

    NASA Astrophysics Data System (ADS)

    Theune, Ulrich

    In the past decades, remote monitoring of subsurface processes has attracted increasing attention in geophysics. With repeated geophysical surveys one attempts to detect changes in the physical properties in the underground without directly accessing the earth. This technique has been proven to be very valuable for monitoring enhanced oil recovery programs. This thesis presents an modelling approach for the feasibility analysis for monitoring of a thermal enhanced oil recovery technique applied to heavy oil reservoirs in the Western Canadian Sedimentary Basin. In order to produce heavy oil from shallow reservoirs thermal oil recovery techniques such as the Steam Assisted Gravity Drainage (SAGD) are often employed. As these techniques are expensive and technically challenging, early detection of operational problems is without doubt of great value. However, the feasibility of geophysical monitoring depends on many factors such as the changes in the rock physical properties of the target reservoir. In order to access the feasibility of seismic monitoring for heavy oil reservoirs, a fluid-substitutional rock physical study has been carried out to simulate the steam injection. The second modelling approach is based on a modified finite element algorithm to simulate the propagation of elastic waves in the earth, which has been developed independently in the framework of this thesis. The work summarized in this thesis shows a possibility to access the feasibility of seismic monitoring for heavy oil reservoirs through an extensive rock-physical study. Seismic monitoring is a useful tool in reservoir management decision process. However, the work reported here suggests that seismic monitoring of SAGD processes in the heavy oil reservoirs of the Western Canadian Sedimentary Basin is only feasible in shallow, unconsolidated deposits. For deeper, but otherwise geological similar reservoirs, the SAGD does not create a sufficient change in the rock physical properties to be

  13. Seismic monitoring in the oceans by autonomous floats.

    PubMed

    Sukhovich, Alexey; Bonnieux, Sébastien; Hello, Yann; Irisson, Jean-Olivier; Simons, Frederik J; Nolet, Guust

    2015-01-01

    Our understanding of the internal dynamics of the Earth is largely based on images of seismic velocity variations in the mantle obtained with global tomography. However, our ability to image the mantle is severely hampered by a lack of seismic data collected in marine areas. Here we report observations made under different noise conditions (in the Mediterranean Sea, the Indian and Pacific Oceans) by a submarine floating seismograph, and show that such floats are able to fill the oceanic data gap. Depending on the ambient noise level, the floats can record between 35 and 63% of distant earthquakes with a moment magnitude M≥6.5. Even magnitudes <6.0 can be successfully observed under favourable noise conditions. The serendipitous recording of an earthquake swarm near the Indian Ocean triple junction enabled us to establish a threshold magnitude between 2.7 and 3.4 for local earthquakes in the noisiest of the three environments. PMID:26289598

  14. Seismic monitoring in the oceans by autonomous floats

    NASA Astrophysics Data System (ADS)

    Sukhovich, Alexey; Bonnieux, Sébastien; Hello, Yann; Irisson, Jean-Olivier; Simons, Frederik J.; Nolet, Guust

    2015-08-01

    Our understanding of the internal dynamics of the Earth is largely based on images of seismic velocity variations in the mantle obtained with global tomography. However, our ability to image the mantle is severely hampered by a lack of seismic data collected in marine areas. Here we report observations made under different noise conditions (in the Mediterranean Sea, the Indian and Pacific Oceans) by a submarine floating seismograph, and show that such floats are able to fill the oceanic data gap. Depending on the ambient noise level, the floats can record between 35 and 63% of distant earthquakes with a moment magnitude M>=6.5. Even magnitudes <6.0 can be successfully observed under favourable noise conditions. The serendipitous recording of an earthquake swarm near the Indian Ocean triple junction enabled us to establish a threshold magnitude between 2.7 and 3.4 for local earthquakes in the noisiest of the three environments.

  15. Seismic monitoring in the oceans by autonomous floats

    PubMed Central

    Sukhovich, Alexey; Bonnieux, Sébastien; Hello, Yann; Irisson, Jean-Olivier; Simons, Frederik J.; Nolet, Guust

    2015-01-01

    Our understanding of the internal dynamics of the Earth is largely based on images of seismic velocity variations in the mantle obtained with global tomography. However, our ability to image the mantle is severely hampered by a lack of seismic data collected in marine areas. Here we report observations made under different noise conditions (in the Mediterranean Sea, the Indian and Pacific Oceans) by a submarine floating seismograph, and show that such floats are able to fill the oceanic data gap. Depending on the ambient noise level, the floats can record between 35 and 63% of distant earthquakes with a moment magnitude M≥6.5. Even magnitudes <6.0 can be successfully observed under favourable noise conditions. The serendipitous recording of an earthquake swarm near the Indian Ocean triple junction enabled us to establish a threshold magnitude between 2.7 and 3.4 for local earthquakes in the noisiest of the three environments. PMID:26289598

  16. Seismic monitoring at the Geysers geothermal field, California

    USGS Publications Warehouse

    Marks, S.M.; Ludwin, R.S.; Louie, K.B.; Bufe, C.G.

    1978-01-01

    Two distinct clusters of microearthquakes have been identified at The Geysers, possibly relating to two independent pressure sinks resulting from steam production described by Lipman, and others (1977). Unlike earthquakes in the Maacama-Rodgers Creek fault zone to the south and west, earthquakes at The Geysers are confined to depths of less than 5 km. The present level of seismicity at The Geysers appears to be higher than the preproduction level and is higher and more continuous than the seismicity in the surrounding region. Earthquakes in the steam production zone at The Geysers resemble earthquakes in the surrounding region with regard to focal plane solutions, source characteristics and magnitude distribution (b slope). Subtle differences in earthquake characteristics may be resolved by analysis of more extensive data now being gathered in the region.

  17. Seismic monitoring in the oceans by autonomous floats.

    PubMed

    Sukhovich, Alexey; Bonnieux, Sébastien; Hello, Yann; Irisson, Jean-Olivier; Simons, Frederik J; Nolet, Guust

    2015-08-20

    Our understanding of the internal dynamics of the Earth is largely based on images of seismic velocity variations in the mantle obtained with global tomography. However, our ability to image the mantle is severely hampered by a lack of seismic data collected in marine areas. Here we report observations made under different noise conditions (in the Mediterranean Sea, the Indian and Pacific Oceans) by a submarine floating seismograph, and show that such floats are able to fill the oceanic data gap. Depending on the ambient noise level, the floats can record between 35 and 63% of distant earthquakes with a moment magnitude M≥6.5. Even magnitudes <6.0 can be successfully observed under favourable noise conditions. The serendipitous recording of an earthquake swarm near the Indian Ocean triple junction enabled us to establish a threshold magnitude between 2.7 and 3.4 for local earthquakes in the noisiest of the three environments.

  18. Using powerful vibrators for calibration of seismic traces in nuclear explosion monitoring problems.

    NASA Astrophysics Data System (ADS)

    Glinsky, B.; Kovalevsky, V.; Seleznev, V.; Emanov, A.; Soloviev, V.

    2009-04-01

    The efficiency of functioning of the International Seismic Monitoring System (ISMS) is connected with the accuracy of the location and identification of a source of seismic waves which can be nuclear explosion. The errors in the determination of the location are caused by local and regional variations of wave hodographs. Empirical approach to solving these problems is to use events for which the locations and times are known, in order to determine a set of corrections to the regional model of wave propagation. The using of powerful vibrators for calibration of seismic traces is a new way in nuclear explosion monitoring problems. Now the 60-100 tons force vibrator can radiate the signals which can be recorded at the distances up to 500 km and can be used for regional calibration of seismic traces. The comparison of the seismic wave fields of powerful vibrators and 100-ton chemical explosion "Omega-3" at the 630-km profile, quarry explosions of the Kuznetsk basin with power from 50 to 700 tons at the distances up to 355 km showed their equivalence in the main types of waves. The paper presents the results of experiments of long-distance recording of seismic signals of powerful vibrators and detailed investigation of the velocity characteristics of the Earth's crust in West Siberia and Altay-Sayan region.

  19. Using powerful vibrators for calibration of seismic traces in nuclear explosion monitoring problems

    NASA Astrophysics Data System (ADS)

    Glinsky, B.; Kovalevsky, V.; Seleznev, V.; Emanov, A.; Soloviev, V.

    2009-04-01

    The efficiency of functioning of the International Seismic Monitoring System (ISMS) is connected with the accuracy of the location and identification of a source of seismic waves which can be nuclear explosion. The errors in the determination of the location are caused by local and regional variations of wave hodographs. Empirical approach to solving these problems is to use events for which the locations and times are known, in order to determine a set of corrections to the regional model of wave propagation. The using of powerful vibrators for calibration of seismic traces is a new way in nuclear explosion monitoring problems. Now the 60-100 tons force vibrator can radiate the signals which can be recorded at the distances up to 500 km and can be used for regional calibration of seismic traces. The comparison of the seismic wave fields of powerful vibrators and 100-ton chemical explosion "Omega-3" at the 630-km profile, quarry explosions of the Kuznetsk basin with power from 50 to 700 tons at the distances up to 355 km showed their equivalence in the main types of waves. The paper presents the results of experiments of long-distance recording of seismic signals of powerful vibrators and detailed investigation of the velocity characteristics of the Earth's crust in West Siberia and Altay-Sayan region.

  20. Crosswell seismic and electromagnetic monitoring of CO2sequestration

    SciTech Connect

    Hoversten, G. Michael; Gritto, Roland; Daley, Thomas M.; Majer,Ernest L.; Myer, Larry R.

    2002-07-30

    The quantitative estimation of changes in water saturation (S{sub W}) and effective pressure (P), in terms of changes in compressional and shear impedance, is becoming routine in the interpretations of time-lapse surface seismic data. However, when the number of reservoir constituents increases to include in situ gas and injected CO{sub 2}, there are too many parameters to be determined from seismic velocities or impedances alone. In such situations, the incorporation of electromagnetic (EM) images showing the change in electrical conductivity ({sigma}) provides essential independent information. The purpose of this study was to demonstrate a methodology for jointly interpreting crosswell seismic and EM data, in conjunction with detailed constitutive relations between geophysical and reservoir parameters, to quantitatively predict changes in P, S{sub W}, CO{sub 2} gas saturation (S{sub CO2}), CO{sub 2} gas/oil ratio (R{sub CO{sub 2}}), hydrocarbon gas saturation (S{sub g}), and hydrocarbon gas/oil ration (R{sub g}) in a reservoir undergoing CO{sub 2} flood.

  1. A Fusion Model of Seismic and Hydro-Acoustic Propagation for Treaty Monitoring

    NASA Astrophysics Data System (ADS)

    Arora, Nimar; Prior, Mark

    2014-05-01

    We present an extension to NET-VISA (Network Processing Vertically Integrated Seismic Analysis), which is a probabilistic generative model of the propagation of seismic waves and their detection on a global scale, to incorporate hydro-acoustic data from the IMS (International Monitoring System) network. The new model includes the coupling of seismic waves into the ocean's SOFAR channel, as well as the propagation of hydro-acoustic waves from underwater explosions. The generative model is described in terms of multiple possible hypotheses -- seismic-to-hydro-acoustic, under-water explosion, other noise sources such as whales singing or icebergs breaking up -- that could lead to signal detections. We decompose each hypothesis into conditional probability distributions that are carefully analyzed and calibrated. These distributions include ones for detection probabilities, blockage in the SOFAR channel (including diffraction, refraction, and reflection around obstacles), energy attenuation, and other features of the resulting waveforms. We present a study of the various features that are extracted from the hydro-acoustic waveforms, and their correlations with each other as well the source of the energy. Additionally, an inference algorithm is presented that concurrently infers the seismic and under-water events, and associates all arrivals (aka triggers), both from seismic and hydro-acoustic stations, to the appropriate event, and labels the path taken by the wave. Finally, our results demonstrate that this fusion of seismic and hydro-acoustic data leads to very good performance. A majority of the under-water events that IDC (International Data Center) analysts built in 2010 are correctly located, and the arrivals that correspond to seismic-to-hydroacoustic coupling, the T phases, are mostly correctly identified. There is no loss in the accuracy of seismic events, in fact, there is a slight overall improvement.

  2. Seismic monitoring of soft-rock landslides: New case study at Pechgraben mudslide - Upper Austria

    NASA Astrophysics Data System (ADS)

    Vouillamoz, Naomi; Santoyo, Juan Carlos; Ottowitz, David; Jochum, Birgit; Pfeiler, Stefan; Supper, Robert; Joswig, Manfred

    2016-04-01

    Creeping soft-rock landslides trigger various seismic signals which relate to key dynamics of the slope instability. A new seismic monitoring study is carried out at Pechgraben - Upper Austria, where a clay-shale rich mudslide was reactivated in summer 2013 after heavy rainfalls. The well geophysical instrumentation of the Pechgraben mudslide by the Geological Survey of Austria (LAMOND network including permanent ERT, GPS, piezometers, soil temperature/humidity and photomonitoring) is expected as a better basis for joint interpretation of seismic source processes. Seismic data are acquired by small-aperture (< 30 m) sparse seismic arrays. Potential events are recognized by frequency-time signatures in sonograms, where sonograms are spectrograms featuring a frequency-dependant noise adaptation that enhance the display of weak signal energy down to the noise threshold. Further signal evaluation follows an interactive scheme where semi-automated beam forming method enables for approximate source location. Three seismic arrays where deployed at Pechgraben in October 2015 for an eight days feasibility study. About 200 seismic signals potentially triggered by the landslide were manually picked on night-time measurements. Target signals occur in tremor-like sequences and have duration within 1 - 8 seconds. Local magnitudes are calibrated down to ML -1.5 (Wood-Anderson amplitude ≈ 0.1 μm in 100 m distance). Observed waveforms display high degree of similarity with seismic signals catalogued at other soft-rock landslides suggesting that a general typology of seismic source processes could be established for creeping soft-rock instabilities with potential further implications in landslide mitigation and forecasting.

  3. Initial results from seismic monitoring at the Aquistore CO2 storage site, Saskatchewan, Canada

    DOE PAGES

    White, D. J.; Roach, L. A.N.; Roberts, B.; Daley, T. M.

    2014-12-31

    The Aquistore Project, located near Estevan, Saskatchewan, is one of the first integrated commercial-scale CO2 storage projects in the world that is designed to demonstrate CO2 storage in a deep saline aquifer. Starting in 2014, CO2 captured from the nearby Boundary Dam coal-fired power plant will be transported via pipeline to the storage site and to nearby oil fields for enhanced oil recovery. At the Aquistore site, the CO2 will be injected into a brine-filled sandstone formation at ~3200 m depth using the deepest well in Saskatchewan. The suitability of the geological formations that will host the injected CO2 hasmore » been predetermined through 3D characterization using high-resolution 3D seismic images and deep well information. These data show that 1) there are no significant faults in the immediate area of the storage site, 2) the regional sealing formation is continuous in the area, and 3) the reservoir is not adversely affected by knolls on the surface of the underlying Precambrian basement. Furthermore, the Aquistore site is located within an intracratonic region characterized by extremely low levels of seismicity. This is in spite of oil-field related water injection in the nearby Weyburn-Midale field where a total of 656 million m3 of water have been injected since the 1960`s with no demonstrable related induced seismicity. A key element of the Aquistore research program is the further development of methods to monitor the security and subsurface distribution of the injected CO2. Toward this end, a permanent areal seismic monitoring array was deployed in 2012, comprising 630 vertical-component geophones installed at 20 m depth on a 2.5x2.5 km regular grid. This permanent array is designed to provide improved 3D time-lapse seismic imaging for monitoring subsurface CO2. Prior to the onset of CO2 injection, calibration 3D surveys were acquired in May and November of 2013. Comparison of the data from these surveys relative to the baseline 3D survey data

  4. Seismic and Tilt Data Processing for Monitoring Groundwater Contamination

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Spetzler, H. A.

    2003-12-01

    We are conducting a feasibility study to see if we can detect changes in the state of saturation in groundwater by seismic means. This field study is based on laboratory experiments that show large changes in seismic attenuation when contaminants change the wettability of porous rocks. Three tiltmeters and three seismometers were installed at different distances from a controlled irrigation site near Maricopa, AZ. The research site has a facility to controllably irrigate a 50 m by 50 m area with water and chemical surfactants. The instruments are used to record naturally-occurring, low frequency strain and seismic signals before, during and after irrigations. The purpose of the data analysis is to develop techniques for looking for the differences in station response due to local differences, such as contamination in the vadose zone and groundwater. Ours is not a conventional way of data processing for our non-traditional use of the data, since the variations in instrument response caused by the trace amount of contaminants are very small. We are looking for small changes in the relative response between the instruments. For the seismic data, not only do we examine large events, such as Earthquakes, but also microseisms. We use microseisms as our source and the related processing is an attempt to measure the tiny changes in instrument response caused by differences in irrigation and contamination at the three different locations. In tilt data processing, the large events caused by regional water pumping, oil productions, and Earthquakes, etc. need to be removed, since we wish to use the Earth solid tide as our strain source. The key issue during the process of removing the large events is to make sure that the tide signals are not also removed or greatly distorted. A method and corresponding codes were developed for automatically removing data at the three stations induced by large events. After completing this processing, the signal left is the local Earth tide

  5. Improving the Detectability of the Catalan Seismic Network for Local Seismic Activity Monitoring

    NASA Astrophysics Data System (ADS)

    Jara, Jose Antonio; Frontera, Tànit; Batlló, Josep; Goula, Xavier

    2016-04-01

    The seismic survey of the territory of Catalonia is mainly performed by the regional seismic network operated by the Cartographic and Geologic Institute of Catalonia (ICGC). After successive deployments and upgrades, the current network consists of 16 permanent stations equipped with 3 component broadband seismometers (STS2, STS2.5, CMG3ESP and CMG3T), 24 bits digitizers (Nanometrics Trident) and VSAT telemetry. Data are continuously sent in real-time via Hispasat 1D satellite to the ICGC datacenter in Barcelona. Additionally, data from other 10 stations of neighboring areas (Spain, France and Andorra) are continuously received since 2011 via Internet or VSAT, contributing both to detect and to locate events affecting the region. More than 300 local events with Ml ≥ 0.7 have been yearly detected and located in the region. Nevertheless, small magnitude earthquakes, especially those located in the south and south-west of Catalonia may still go undetected by the automatic detection system (DAS), based on Earthworm (USGS). Thus, in order to improve the detection and characterization of these missed events, one or two new stations should be installed. Before making the decision about where to install these new stations, the performance of each existing station is evaluated taking into account the fraction of detected events using the station records, compared to the total number of events in the catalogue, occurred during the station operation time from January 1, 2011 to December 31, 2014. These evaluations allow us to build an Event Detection Probability Map (EDPM), a required tool to simulate EDPMs resulting from different network topology scenarios depending on where these new stations are sited, and becoming essential for the decision-making process to increase and optimize the event detection probability of the seismic network.

  6. A study of the feasibility of monitoring sealed geological repositories using seismic sensors

    SciTech Connect

    Garbin, H.D.; Herrington, P.B.; Kromer, R.P.

    1997-10-01

    Questions have arisen regarding the applicability of seismic sensors to detect mining (re-entry) with a tunnel boring machine (TBM). Unlike cut and blast techniques of mining which produce impulsive seismic signals, the TBM produces seismic signals which are of long duration. (There are well established techniques available for detecting and locating the sources of the impulsive signals.) The Yucca Mountain repository offered an opportunity to perform field evaluations of the capabilities of seismic sensors because during much of 1996, mining there was progressing with the use of a TBM. During the mining of the repository`s southern branch, an effort was designed to evaluate whether the TBM could be detected, identified and located using seismic sensors. Three data acquisition stations were established in the Yucca Mountain area to monitor the TBM activity. A ratio of short term average to long term average algorithm was developed for use in detection based on the characteristics shown in the time series. For location of the source of detected signals, FK analysis was used on the array data to estimate back azimuths. The back azimuth from the 3 component system was estimated from the horizontal components. Unique features in the timing of the seismic signal were used to identify the source as the TBM.

  7. Monitoring Velocity Changes Caused By Underground Coal Mining Using Seismic Noise

    NASA Astrophysics Data System (ADS)

    Czarny, Rafał; Marcak, Henryk; Nakata, Nori; Pilecki, Zenon; Isakow, Zbigniew

    2016-06-01

    We use passive seismic interferometry to monitor temporal variations of seismic wave velocities at the area of underground coal mining named Jas- Mos in Poland. Ambient noise data were recorded continuously for 42 days by two three-component broadband seismometers deployed at the ground surface. The sensors are about 2.8 km apart, and we measure the temporal velocity changes between them using cross-correlation techniques. Using causal and acausal parts of nine-component cross-correlation functions (CCFs) with a stretching technique, we obtain seismic velocity changes in the frequency band between 0.6 and 1.2 Hz. The nine-component CCFs are useful to stabilize estimation of velocity changes. We discover correlation between average velocity changes and seismic events induced by mining. Especially after an event occurred between the stations, the velocity decreased about 0.4 %. Based on this study, we conclude that we can monitor the changes of seismic velocities, which are related to stiffness, effective stress, and other mechanical properties at subsurface, caused by mining activities even with a few stations.

  8. Analysis of the seismicity in the region of Mirovo salt mine after 8 years monitoring

    NASA Astrophysics Data System (ADS)

    Dimitrova, Liliya; Solakov, Dimcho; Simeonova, Stela; Aleksandrova, Irena; Georgieva, Gergana

    2015-04-01

    Mirovo salt deposit is situated in the NE part of Bulgaria and 5 kilometers away from the town of Provadiya. The mine is in operation since 1956. The salt is produced by dilution and extraction of the brine to the surface. A system of chambers-pillars is formed within the salt body as a result of the applied technology. The mine is situated in a seismically quiet part of the state. The region is characterized with complex geological structure and several faults. During the last 3 decades a large number of small and moderate earthquakes (M<4.5) are realized in the close vicinity of the salt deposit. Local seismological network (LSN) is deployed in the region to monitor the local seismicity. It consists of 6 three component digital stations. A real-time data transfer from LSN stations to National Data Center (in Sofia) is implemented using the VPN and MAN networks of the Bulgarian Telecommunication Company. Common processing and interpretation of the data from LSN and the national seismic network is performed. Real-time and interactive data processing are performed by the Seismic Network Data Processor (SNDP) software package. More than 700 earthquakes are registered by the LSN within 30km region around the mine during the 8 years monitoring. First we processed the data and compile a catalogue of the earthquakes occur within the studied region (30km around the salt mine). Spatial pattern of seismicity is analyzed. A large number of the seismic events occurred within the northern and north-western part of the salt body. Several earthquakes occurred in close vicinity of the mine. Concerning that the earthquakes could be tectonic and/or induced an attempt is made to find criteria to distinguish natural from induced seismicity. To characterize and distinguish the main processes active in the area we also made waveform and spectral analysis of a number of earthquakes.

  9. The Irpinia Seismic Network (ISN): a new Monitoring Infrastructure for Seismic Alert Management in Campania Region, Southern Italy

    NASA Astrophysics Data System (ADS)

    Iannaccone, G.; Satriano, C.; Weber, E.; Cantore, L.; Corciulo, M.; Romano, L.; Martino, C.; Dicrosta, M.; Zollo, A.

    2005-12-01

    The Irpinia Seismic Network is an high dynamics, high density seismographic network under development in the Southern Apenninic chain. It is deployed in the area stroken by several destructive earthquakes during last centuries. In its final configuration the network will consist of more than fourty high dynamic seismic stations subdivided in physical subnetworks inter-connected by a robust data transmission system. The system is being designed with two primary targets: -Monitoring and analysis of background seismic activity produced by the active fault system which is the cause for large earthquakes in the past, included the 1980, Irpinia earthquake (Ms=6.9) - Development and experimentation of a prototype system for seismic early and post-event warning to be used for protecting public infrastructures and buildings of strategic relevance of the Regione Campania The seismic network will be completed in two stages: 1 - Deployment of 30 seismic stations along the Campania-Lucania Apenninic chain (to date almost completed) 2 - Setting up radio communication system for data transmission. Installation of 12 additional seismic stations (end of year 2006) To ensure an high dynamic recording range each site is equipped with two type of sensors: 30 force-balance accelerometer (model Guralp CMG5-T) and a velocimeter. In particular, 25 sites with short period three components instrument (model Geotech S13-J) and 5 with broad-band sensor (Nanometrics Trillium, with frequency response in the 0.033-50 Hz band). The used data logger is the Osiris-6 model produced by Agecodagis whose main features are: six channels, O/N 24 bit A/D converter, ARM processor with embedded Linux and open source software, two PCMCIA slots (used for two 5GB microdrive or one disk and wi-fi card), Ethernet, wi-fi and serial communication, low power cosumption (~1 W). Power is ensured by two 120 W solar panels and two 130 Ah gel batteries. Each recording site is equipped with a control/alarm system through

  10. Monitoring induced seismicity from underground gas storage: first steps in Italy

    NASA Astrophysics Data System (ADS)

    Mucciarelli, Marco; Priolo, Enrico

    2013-04-01

    The supply of natural gas and its storage are focal points of the Italian politics of energy production and will have increasing importance in the coming years. About a dozen reservoirs are currently in use and fifteen are in development or awaiting approval. Some of these are found in the vicinity of geological structures that are seismically active. The assessment of seismic hazard (both for natural background and induced seismicity) for a geological gas storage facility has a number of unconventional aspects that must be recognized and traced in a clear, ordered way and using guidelines and rules that leave less room as possible for interpretation by the individual applicant / verification body. Similarly, for control and monitoring there are not clearly defined procedures or standard instrumentation, let alone tools for analysing and processing data. Finally, governmental organizations in charge of permission grants and operative control tend to have appropriate scientific knowledge only in certain areas and not in others (e.g. the seismic one), and the establishment of an independent multidisciplinary inspection body appears desirable. The project StoHaz (https://sites.google.com/site/s2stohaz/home) aims to initiate a series of actions to overcome these deficiencies and allow to define procedures and standards for the seismic hazard assessment and control of the activities of natural gas storage in underground reservoirs. OGS will take advantage of the experience gained with the design, installation and maintenance of the seismic network monitoring the Collalto reservoir, at the moment the only example in Italy of a public research institution monitoring independently the activities of a private gas storage company.

  11. Application of collocated GPS and seismic sensors to earthquake monitoring and early warning.

    PubMed

    Li, Xingxing; Zhang, Xiaohong; Guo, Bofeng

    2013-10-24

    We explore the use of collocated GPS and seismic sensors for earthquake monitoring and early warning. The GPS and seismic data collected during the 2011 Tohoku-Oki (Japan) and the 2010 El Mayor-Cucapah (Mexico) earthquakes are analyzed by using a tightly-coupled integration. The performance of the integrated results is validated by both time and frequency domain analysis. We detect the P-wave arrival and observe small-scale features of the movement from the integrated results and locate the epicenter. Meanwhile, permanent offsets are extracted from the integrated displacements highly accurately and used for reliable fault slip inversion and magnitude estimation.

  12. Local seismic network for monitoring of a potential nuclear power plant area

    NASA Astrophysics Data System (ADS)

    Tiira, Timo; Uski, Marja; Kortström, Jari; Kaisko, Outi; Korja, Annakaisa

    2016-04-01

    This study presents a plan for seismic monitoring of a region around a potential nuclear power plant. Seismic monitoring is needed to evaluate seismic risk. The International Atomic Energy Agency has set guidelines on seismic hazard evaluation and monitoring of such areas. According to these guidelines, we have made a plan for a local network of seismic stations to collect data for seismic source characterization and seismotectonic interpretations, as well as to monitor seismic activity and natural hazards. The detection and location capability of the network were simulated using different station configurations by computing spatial azimuthal coverages and detection threshold magnitudes. Background noise conditions around Pyhäjoki were analyzed by comparing data from different stations. The annual number of microearthquakes that should be detected with a dense local network centered around Pyhäjoki was estimated. The network should be dense enough to fulfill the requirements of azimuthal coverage better than 180° and automatic event location capability down to ML ˜ 0 within a distance of 25 km from the site. A network of 10 stations should be enough to reach these goals. With this setup, the detection threshold magnitudes are estimated to be ML = -0.1 and ML = 0.1 within a radius of 25 and 50 km from Pyhäjoki, respectively. The annual number of earthquakes detected by the network is estimated to be 2 (ML ≥ ˜ -0.1) within 25 km radius and 5 (ML ≥ ˜-0.1 to ˜0.1) within 50 km radius. The location accuracy within 25 km radius is estimated to be 1-2 and 4 km for horizontal coordinates and depth, respectively. Thus, the network is dense enough to map out capable faults with horizontal accuracy of 1-2 km within 25 km radius of the site. The estimation is based on the location accuracies of five existing networks in northern Europe. Local factors, such as seismic noise sources, geology and infrastructure might limit the station configuration and detection and

  13. SA-based concrete seismic stress monitoring: a case study for normal strength concrete

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2016-09-01

    The stress history of concrete structures that have survived an earthquake can serve as a critical index to evaluate the health of the structure. There are currently few reliable monitoring methods to assess concrete stress after a seismic event. Piezoelectric-based smart aggregate (SA) provides an innovative experimental approach to monitor stress on concrete. The principle of SA-based concrete seismic stress monitoring is based on the assumption that concrete stress can be reliably predicted by the average output voltages of limited SAs with an acceptable margin of error. In this study, the meso-scale randomness of concrete was evaluated throughout the overall stress range of concrete and the influence of different load paths was considered. Four cylindrical specimens of normal strength concrete were embedded with a total of 24 SAs. The SA output sensitivity curve in the paths of loading-unloading with different amplitudes and monotonic loading up to failure was obtained. Monitoring errors were analyzed during pre- and post-peak stages from the experimental results. This research suggests that SA-based concrete seismic stress monitoring for normal strength concrete is reliable.

  14. SA-based concrete seismic stress monitoring: a case study for normal strength concrete

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2016-09-01

    The stress history of concrete structures that have survived an earthquake can serve as a critical index to evaluate the health of the structure. There are currently few reliable monitoring methods to assess concrete stress after a seismic event. Piezoelectric-based smart aggregate (SA) provides an innovative experimental approach to monitor stress on concrete. The principle of SA-based concrete seismic stress monitoring is based on the assumption that concrete stress can be reliably predicted by the average output voltages of limited SAs with an acceptable margin of error. In this study, the meso-scale randomness of concrete was evaluated throughout the overall stress range of concrete and the influence of different load paths was considered. Four cylindrical specimens of normal strength concrete were embedded with a total of 24 SAs. The SA output sensitivity curve in the paths of loading–unloading with different amplitudes and monotonic loading up to failure was obtained. Monitoring errors were analyzed during pre- and post-peak stages from the experimental results. This research suggests that SA-based concrete seismic stress monitoring for normal strength concrete is reliable.

  15. Monitoring South-West Greenland's ice sheet melt with ambient seismic noise

    NASA Astrophysics Data System (ADS)

    Mordret, Aurélien; Mikesell, Dylan; Harig, Christopher; Lipovsky, Brad; Prieto, German

    2016-04-01

    The Greenland ice sheet (GIS) accounts for ~ 70% of global ice sheet mass loss and contributes to sea level rise at a rate of 0.7 mm/yr. Therefore, the GIS needs to be carefully monitored. The spaceborne techniques commonly used to monitor the GIS mass balance contain inherent uncertainties. These uncertainties can be reduced by comparing independent datasets and techniques. However, spaceborne methods remain inadequate in the sense that they offer low spatial and/or temporal resolution. This fact highlights the need for other complementary methods to monitor the GIS more accurately and with greater resolution. Here we use a seismic method: the correlation of seismic noise recorded at South-West Greenland seismic stations to show that the GIS seasonal melt produces significant variations of seismic wave speed in the Greenland crust. The amplitudes of the measured velocity variations during 2012-2013 correlate with the total ice plus atmospheric mass variations measured by the GRACE (Gravity Recovery and Climate Experiment) satellite mission. We explain the phase delay between mass maxima and velocity minima ( 50 days) using a non-linear poroelastic model that includes a 55 cm-thick layer of till between the ice sheet and the bedrock. We, thus, interpret the velocity variations as pore pressure variations in the bedrock resulting from the loading and unloading of the overlying glacier and atmosphere. This method provides a new and independent way to monitor in near real-time the first-order state of the GIS, giving new constraints on its evolution and its contribution to the global sea level rise. By increasing the density of seismic stations in the region it will be possible to increase the spatial and temporal resolution of the method and create detailed maps of ice-mass variations across Greenland.

  16. Monitoring South-West Greenland's ice sheet melt with ambient seismic noise

    NASA Astrophysics Data System (ADS)

    Mordret, A.; Mikesell, T. D.; Harig, C.; Lipovsky, B.; Prieto, G. A.

    2015-12-01

    The Greenland ice sheet (GIS) accounts for ~ 70% of global ice sheet mass loss and contributes to sea level rise at a rate of 0.7 mm/yr. Therefore, the GIS needs to be carefully monitored. The spaceborne techniques commonly used to monitor the GIS mass balance contain inherent uncertainties. These uncertainties can be reduced by comparing independent datasets and techniques. However, spaceborne methods remain inadequate in the sense that they offer low spatial and/or temporal resolution. This fact highlights the need for other complimentary methods to monitor the GIS more accurately and with greater resolution. Here we use a seismic method: the correlation of seismic noise recorded at South-West Greenland seismic stations to show that the GIS seasonal melt produces significant variations of seismic wave speed in the Greenland crust. The amplitudes of the measured velocity variations during 2012-2013 correlate with the total ice plus atmospheric mass variations measured by the GRACE (Gravity Recovery and Climate Experiment) satellite mission. We explain the phase delay between mass maxima and velocity minima ( 50 days) using a non-linear poroelastic model that includes a 55 cm-thick layer of till between the ice sheet and the bedrock. We, thus, interpret the velocity variations as pore pressure variations in the bedrock resulting from the loading and unloading of the overlying glacier and atmosphere. This method provides a new and independent way to monitor in near real-time the first-order state of the GIS, giving new constraints on its evolution and its contribution to the global sea level rise. By increasing the density of seismic stations in the region it will be possible to increase the spatial and temporal resolution of the method and create detailed maps of ice-mass variations across Greenland.

  17. The evolution of seismic monitoring systems at the Hawaiian Volcano Observatory: Chapter 2 in Characteristics of Hawaiian volcanoes

    USGS Publications Warehouse

    Okubo, Paul G.; Nakata, Jennifer S.; Koyanagi, Robert Y.; Poland, Michael P.; Takahashi, T. Jane; Landowski, Claire M.

    2014-01-01

    In the century since the Hawaiian Volcano Observatory (HVO) put its first seismographs into operation at the edge of Kīlauea Volcano’s summit caldera, seismic monitoring at HVO (now administered by the U.S. Geological Survey [USGS]) has evolved considerably. The HVO seismic network extends across the entire Island of Hawai‘i and is complemented by stations installed and operated by monitoring partners in both the USGS and the National Oceanic and Atmospheric Administration. The seismic data stream that is available to HVO for its monitoring of volcanic and seismic activity in Hawai‘i, therefore, is built from hundreds of data channels from a diverse collection of instruments that can accurately record the ground motions of earthquakes ranging in magnitude from <1 to ≥8. In this chapter we describe the growth of HVO’s seismic monitoring systems throughout its first hundred years of operation. Although other references provide specific details of the changes in instrumentation and data handling over time, we recount here, in more general terms, the evolution of HVO’s seismic network. We focus not only on equipment but also on interpretative products and results that were enabled by the new instrumentation and by improvements in HVO’s seismic monitoring, analytical, and interpretative capabilities implemented during the past century. As HVO enters its next hundred years of seismological studies, it is well situated to further improve upon insights into seismic and volcanic processes by using contemporary seismological tools.

  18. Monitoring co- and pre-seismic motion by geodetic techniques

    NASA Astrophysics Data System (ADS)

    Groten, E.

    1992-02-01

    A recently built extensometer, which is based on a highly stable capacitance transducer, as well as a liquid bubble Hughes tiltmeter are discussed in view of monitoring strain and deformations at the Earth's surface. These instruments are being used to control local variations, whereas regional and global changes, including gravity variations, are monitored using repeated GPS and very precise relative gravimetry. With sufficient exterior control (such as absolute gravimetry for calibration, tidal measurements for separating tidal from other effects) we will acquire a more or less complete system (in combination with local leveling etc. as used by several other authors as well) for determination of time-dependent phenomena.

  19. Monitoring of injected CO2 using the seismic full waveform inversion for 2-D elastic VTI media

    NASA Astrophysics Data System (ADS)

    Kim, W. K.; Min, D. J.; KIM, S.; Shin, Y.; Moon, S.

    2014-12-01

    To monitor the injected CO2 in the subsurface, seismic monitoring techniques are extensively applied because of its high resolution. Among the seismic monitoring techniques, seismic full waveform inversion (FWI) has high applicability because it can delineate parameter changes by injected CO2. When seismic FWIs are applied, subsurface media can be generally assumed to be isotropic. However, most subsurface media are not isotropic, and shale is a representative anisotropic medium, particularly vertical transversely isotropic (VTI) medium, which is often encountered as a barrier to injected CO2. Thus, anisotropic properties of subsurface media are important for monitoring of injected CO2. For these issues, we need to consider anisotropy of subsurface media when seismic FWIs are applied as a monitoring tool for CO2 sequestration. In this study, we performed seismic FWI for 2-D elastic VTI media to investigate the effects of anisotropic properties in CO2 monitoring. For this numerical test, we assumed a geological model, which copies after one of CO2 storage prospects in Korea. We also applied seismic FWI algorithm for 2-D elastic isotropic media for comparison. From this comparison, we noticed that we can obtain more reliable results when we apply the anisotropic FWI algorithm. Numerical examples indicate that we should apply the anisotropic FWI algorithm rather than the isotropic FWI algorithm when we interpret seismic monitoring data acquired in anisotropic media to increase the success of monitoring for injected CO2. Our numerical results can also be used as references for real seismic monitoring of the Korea CO2 sequestration projects in the near future. Acknowledgements This work was supported by the Human Resources Development program (No. 20134010200510) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korean government Ministry of Trade, Industry, and Energy and by the "Development of Technology for CO2 Marine

  20. Hydrogeological response to tele-seismic events with underground water level precision monitoring data

    NASA Astrophysics Data System (ADS)

    Gorbunova, Ella; Vinogradov, Evgeny; Besedina, Alina; Kabychenko, Nikolay; Svintsov, Igor

    2015-04-01

    Underground water level precision monitoring has been being carried out in the IDG RAS experimental area "Mikhnevo" in step with barometric pressure measuring since February of 2008. Seismic events registration is being realized with small aperture seismic array "Mikhnevo" and STS-2 seismometer. Complex processing of original hydrological and seismic data allows to mark out hydrological responses to large earthquakes (Mw>7.5) seismic waves propagation throw aseismic region - central area of Russian Plate. GPO "Mikhnevo" is located within South part of Moscow artesian basin in the North-East part of Prioksko-Terrasny biosphere reserve out of intensive anthropogenic impact zone. Wellbore unseals index aquifer in the interval of 91-115 m. An aquifer is characterized with season level variations. Water containing rocks are presented with nonuniform fractured limestones. In IDG RAS step-by-step methodic of experimental data handling was devised. First preliminary comparison of 1 Hz frequency seismic and hydrological data is being carried out for hydrogeological response to large earthquakes (Mw>7.5) seismic waves propagation marking out. On basis of these data main types and parameters of waves registered in seismic and hydrological data are being identified and representative periods for geological medium response to tele-seismic events analysis are being selected. In the area of GPO "Mikhnevo" we traced geological response to disastrous earthquakes that took place 02/27/2011 near Central Chile Coast and 03/11/11 near Honshu Island east coast that is presented being smoothed in underground water level. Tele-seismic events differs in intensity, signal duration and post-seismic effect. Significant water level harmonic oscillations are coupled with surface and S-waves arrival, where vertical component prevails First hydrological responses were registered in the time of S-wave propagation 28 minutes after Honshu earthquake beginning and 39 minutes after Chile earthquake

  1. Real-time Seismic Amplitude Measurement (RSAM): a volcano monitoring and prediction tool

    USGS Publications Warehouse

    Endo, E.T.; Murray, T.

    1991-01-01

    Seismicity is one of the most commonly monitored phenomena used to determine the state of a volcano and for the prediction of volcanic eruptions. Although several real-time earthquake-detection and data acquisition systems exist, few continuously measure seismic amplitude in circumstances where individual events are difficult to recognize or where volcanic tremor is prevalent. Analog seismic records provide a quick visual overview of activity; however, continuous rapid quantitative analysis to define the intensity of seismic activity for the purpose of predicing volcanic eruptions is not always possible because of clipping that results from the limited dynamic range of analog recorders. At the Cascades Volcano Observatory, an inexpensive 8-bit analog-to-digital system controlled by a laptop computer is used to provide 1-min average-amplitude information from eight telemetered seismic stations. The absolute voltage level for each station is digitized, averaged, and appended in near real-time to a data file on a multiuser computer system. Raw realtime seismic amplitude measurement (RSAM) data or transformed RSAM data are then plotted on a common time base with other available volcano-monitoring information such as tilt. Changes in earthquake activity associated with dome-building episodes, weather, and instrumental difficulties are recognized as distinct patterns in the RSAM data set. RSAM data for domebuilding episodes gradually develop into exponential increases that terminate just before the time of magma extrusion. Mount St. Helens crater earthquakes show up as isolated spikes on amplitude plots for crater seismic stations but seldom for more distant stations. Weather-related noise shows up as low-level, long-term disturbances on all seismic stations, regardless of distance from the volcano. Implemented in mid-1985, the RSAM system has proved valuable in providing up-to-date information on seismic activity for three Mount St. Helens eruptive episodes from 1985 to

  2. Spatio-temporal variability of abient seismic noise repeatedly monitored above a geothermal reservoir

    NASA Astrophysics Data System (ADS)

    Woith, H.; Parolai, S.; Picozzi, M.; Boxberger, T.; Milkereit, C.; Zschau, J.

    2011-12-01

    shall be investigated by repeated array measurements scheduled for September 2011. At this stage, we have no clear indications for the postulated source effect as a DHI mechanism. To test the last remaining DHI candidate, namely that the fluid reservoir modifies/amplifies incoming seismic waves (site-effect), we intend to continuously monitor the seismic noise on and off the reservoir and compare the response of the reservoir site to earthquakes with the signal at the reference site outside the reservoir.

  3. Seismic-monitoring changes and the remote deployment of seismic stations (seismic spider) at Mount St. Helens, 2004-2005: Chapter 7 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

    USGS Publications Warehouse

    McChesney, Patrick J.; Couchman, Marvin R.; Moran, Seth C.; Lockhart, Andrew B.; Swinford, Kelly J.; LaHusen, Richard G.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

    2008-01-01

    The instruments in place at the start of volcanic unrest at Mount St. Helens in 2004 were inadequate to record the large earthquakes and monitor the explosions that occurred as the eruption developed. To remedy this, new instruments were deployed and the short-period seismic network was modified. A new method of establishing near-field seismic monitoring was developed, using remote deployment by helicopter. The remotely deployed seismic sensor was a piezoelectric accelerometer mounted on a surface-coupled platform. Remote deployment enabled placement of stations within 250 m of the active vent.

  4. Passive monitoring for near surface void detection using traffic as a seismic source

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Kuzma, H. A.; Rector, J.; Nazari, S.

    2009-12-01

    In this poster we present preliminary results based on our several field experiments in which we study seismic detection of voids using a passive array of surface geophones. The source of seismic excitation is vehicle traffic on nearby roads, which we model as a continuous line source of seismic energy. Our passive seismic technique is based on cross-correlation of surface wave fields and studying the resulting power spectra, looking for "shadows" caused by the scattering effect of a void. High frequency noise masks this effect in the time domain, so it is difficult to see on conventional traces. Our technique does not rely on phase distortions caused by small voids because they are generally too tiny to measure. Unlike traditional impulsive seismic sources which generate highly coherent broadband signals, perfect for resolving phase but too weak for resolving amplitude, vehicle traffic affords a high power signal a frequency range which is optimal for finding shallow structures. Our technique results in clear detections of an abandoned railroad tunnel and a septic tank. The ultimate goal of this project is to develop a technology for the simultaneous imaging of shallow underground structures and traffic monitoring near these structures.

  5. Ambient seismic noise monitoring of a clay landslide: Toward failure prediction

    NASA Astrophysics Data System (ADS)

    Mainsant, Guénolé; Larose, Eric; Brönnimann, Cornelia; Jongmans, Denis; Michoud, Clément; Jaboyedoff, Michel

    2012-03-01

    Given that clay-rich landslides may become mobilized, leading to rapid mass movements (earthflows and debris flows), they pose critical problems in risk management worldwide. The most widely proposed mechanism leading to such flow-like movements is the increase in water pore pressure in the sliding mass, generating partial or complete liquefaction. This solid-to-liquid transition results in a dramatic reduction of mechanical rigidity in the liquefied zones, which could be detected by monitoring shear wave velocity variations. With this purpose in mind, the ambient seismic noise correlation technique has been applied to measure the variation in the seismic surface wave velocity in the Pont Bourquin landslide (Swiss Alps). This small but active composite earthslide-earthflow was equipped with continuously recording seismic sensors during spring and summer 2010. An earthslide of a few thousand cubic meters was triggered in mid-August 2010, after a rainy period. This article shows that the seismic velocity of the sliding material, measured from daily noise correlograms, decreased continuously and rapidly for several days prior to the catastrophic event. From a spectral analysis of the velocity decrease, it was possible to determine the location of the change at the base of the sliding layer. These results demonstrate that ambient seismic noise can be used to detect rigidity variations before failure and could potentially be used to predict landslides.

  6. Seismic monitoring of the June, 1988 Salton Sea Scientific Drilling Program flow/injection test

    SciTech Connect

    Jarpe, S.P.; Kasameyer, P.W.; Hutchings, L.J.; Hauk, T.F.

    1988-10-04

    The purpose of the seismic monitoring project was to characterize in detail the micro-seismic activity related to the Salton Sea Scientific Drilling Program (SSSDP) flow-injection test in the Salton Sea Geothermal Field. Our goal was to determine if any sources of seismic energy related to the test were observable at the surface. We deployed our recording stations so that we could detect and locate both impulsive microearthquakes and continuous seismic noise energy. Our network, which was sensitive enough to be triggered by magnitude 0.0 or larger events, found no impulsive microearthquakes in the vicinity of the flow test in the 8 month period before the test and only one event during the flow test. This event has provided the opportunity to compare the detection and location capabilities of small networks and arrays in a geothermal environment. At present, we are carefully scanning all of the data that we collected during the flow test for evidence of anomalous seismic noise sources and for impulsive events smaller than the network detection threshold (magnitude 0.0). 8 refs., 4 figs.

  7. A multi-disciplinary approach for the structural monitoring of Cultural Heritages in a seismic area

    NASA Astrophysics Data System (ADS)

    Fabrizia Buongiorno, Maria; Musacchio, Massimo; Guerra, Ignazio; Porco, Giacinto; Stramondo, Salvatore; Casula, Giuseppe; Caserta, Arrigo; Speranza, Fabio; Doumaz, Fawzi; Giovanna Bianchi, Maria; Luzi, Guido; Ilaria Pannaccione Apa, Maria; Montuori, Antonio; Gaudiosi, Iolanda; Vecchio, Antonio; Gervasi, Anna; Bonali, Elena; Romano, Dolores; Falcone, Sergio; La Piana, Carmelo

    2014-05-01

    In the recent years, the concepts of seismic risk vulnerability and structural health monitoring have become very important topics in the field of both structural and civil engineering for the identification of appropriate risk indicators and risk assessment methodologies in Cultural Heritages monitoring. The latter, which includes objects, building and sites with historical, architectural and/or engineering relevance, concerns the management, the preservation and the maintenance of the heritages within their surrounding environmental context, in response to climate changes and natural hazards (e.g. seismic, volcanic, landslides and flooding hazards). Within such a framework, the complexity and the great number of variables to be considered require a multi-disciplinary approach including strategies, methodologies and tools able to provide an effective monitoring of Cultural Heritages form both scientific and operational viewpoints. Based on this rationale, in this study, an advanced, technological and operationally-oriented approach is presented and tested, which enables measuring and monitoring Cultural Heritage conservation state and geophysical/geological setting of the area, in order to mitigate the seismic risk of the historical public goods at different spatial scales*. The integration between classical geophysical methods with new emerging sensing techniques enables a multi-depth, multi-resolution, and multi-scale monitoring in both space and time. An integrated system of methodologies, instrumentation and data-processing approaches for non-destructive Cultural Heritage investigations is proposed, which concerns, in detail, the analysis of seismogenetic sources, the geological-geotechnical setting of the area and site seismic effects evaluation, proximal remote sensing techniques (e.g. terrestrial laser scanner, ground-based radar systems, thermal cameras), high-resolution aerial and satellite-based remote sensing methodologies (e.g. aeromagnetic surveys

  8. Monitoring southwest Greenland’s ice sheet melt with ambient seismic noise

    PubMed Central

    Mordret, Aurélien; Mikesell, T. Dylan; Harig, Christopher; Lipovsky, Bradley P.; Prieto, Germán A.

    2016-01-01

    The Greenland ice sheet presently accounts for ~70% of global ice sheet mass loss. Because this mass loss is associated with sea-level rise at a rate of 0.7 mm/year, the development of improved monitoring techniques to observe ongoing changes in ice sheet mass balance is of paramount concern. Spaceborne mass balance techniques are commonly used; however, they are inadequate for many purposes because of their low spatial and/or temporal resolution. We demonstrate that small variations in seismic wave speed in Earth’s crust, as measured with the correlation of seismic noise, may be used to infer seasonal ice sheet mass balance. Seasonal loading and unloading of glacial mass induces strain in the crust, and these strains then result in seismic velocity changes due to poroelastic processes. Our method provides a new and independent way of monitoring (in near real time) ice sheet mass balance, yielding new constraints on ice sheet evolution and its contribution to global sea-level changes. An increased number of seismic stations in the vicinity of ice sheets will enhance our ability to create detailed space-time records of ice mass variations. PMID:27386524

  9. Seismicity Characterization and Monitoring at WESTCARB's Proposed Montezuma Hills Geologic Sequestration Site

    SciTech Connect

    Daley, T.M.; Haught, R.; Peterson, J.E.; Boyle, K.; Beyer, J.H.; Hutchings, L.R.

    2010-09-15

    The West Coast Regional Carbon Sequestration Partnership (WESTCARB), in collaboration with Shell Oil Co. performed site characterization for a potential small-scale pilot test of geologic sequestration of carbon dioxide (CO2). The site area, know as Montezuma Hills, is near the town of Rio Vista in northern California. During the process of injection at a CO2 storage site, there is a potential for seismic events due to slippage upon pre-existing discontinuities or due to creation of new fractures. Observations from many injection projects have shown that the energy from these events can be used for monitoring of processes in the reservoir. Typically, the events are of relatively high frequency and very low amplitude. However, there are also well documented (non-CO2-related) cases in which subsurface injection operations have resulted in ground motion felt by near-by communities. Because of the active tectonics in California (in particular the San Andreas Fault system), and the potential for public concern, WESTCARB developed and followed an induced seismicity protocol (Myer and Daley, 2010). This protocol called for assessing the natural seismicity in the area and deploying a monitoring array if necessary. In this report, we present the results of the natural seismicity assessment and the results of an initial temporary deployment of two seismometers at the Montezuma Hills site. Following the temporary array deployment, the project was suspended and the array removed in August of 2010.

  10. Nonbarrier seismic process in the subduction zone and principles of monitoring

    NASA Astrophysics Data System (ADS)

    Gufel'd, I. L.; Novoselov, O. N.

    2015-10-01

    The physics of seismic process in subduction is discussed with the case study of Kamchatka region being considered. Seismic process is not attributed to either cracking or rupturing. Hydrogen degassing controls variations in voluminous-stress state of the geomedium and such parameters of boundary structures as amorphization, texturization, and destruction. Both rapid and slow dynamic processes are controlled by the medium structure and by the parameters of boundaries; these processes are induced by strain autowaves related to reversible structural transformations of the medium at ascending diffusion of hydrogen. Seismic processes are related to rapid or slow disturbance of accommodation of the medium elements relative to each other. Owing to the properties of boundaries, this process runs in a non-barrier manner and has superplasticity features. The monitoring methods for media with active inner energy sources are proposed. Difference equations of system state evolution are used; these equations are derived and corrected from the measurements of structurally sensitive parameters (saying in more precise, seismic wave velocities). Equation of system state evolution, being derived in these dimensions, reflects the effects of interaction between object and medium. As a result of the study, monitoring of phase state of the geomedium is proposed to predict small probability of the strongest earthquakes during the controlled period.

  11. Reprint of "Seismic monitoring of the Plosky Tolbachik eruption in 2012-2013 (Kamchatka Peninsula Russia)"

    NASA Astrophysics Data System (ADS)

    Senyukov, S. L.; Nuzhdina, I. N.; Droznina, S. Ya.; Garbuzova, V. T.; Kozhevnikova, T. Yu.; Sobolevskaya, O. V.; Nazarova, Z. A.; Bliznetsov, V. E.

    2015-12-01

    The active basaltic volcano Plosky Tolbachik (Pl. Tolbachik) is located in the southern part of the Klyuchevskoy volcano group on the Kamchatka Peninsula. The previous 1975-1976 Great Tolbachik Fissure Eruption (1975-1976 GTFE) occurred in the southern sector of Pl. Tolbachik. It was preceded by powerful earthquakes with local magnitudes between 2.5 and 4.9 and it was successfully predicted with a short-term forecast. The Kamchatka Branch of Geophysical Survey (KBGS) of the Russian Academy of Science (RAS) began to publish the results of daily seismic monitoring of active Kamchatka volcanoes on the Internet in 2000. Unlike the 1975-1976 GTFE precursor, (1) seismicity before the 2012-2013 Tolbachik Fissure Eruption (2012-2013 TFE) was relatively weak and earthquake magnitudes did not exceed 2.5. (2) Precursory earthquake hypocenters at 0-5 km depth were concentrated mainly under the southeastern part of the volcano. (3) The frequency of events gradually increased in September 2012, and rose sharply on the eve of the eruption. (4) According to seismic data, the explosive-effusive 2012-2013 TFE began at ~ 05 h 15 min UTC on November 27, 2012; the outbreak occurred between the summit of the Pl. Tolbachik and the Northern Breakthrough of the 1975-1976 GTFE. (5) Because of bad weather, early interpretations of the onset time and the character of the eruption were made using seismological data only and were confirmed later by other monitoring methods. The eruption finished in early September 2013. This article presents the data obtained through real-time seismic monitoring and the results of retrospective analysis, with additional comments on the future monitoring of volcanic activity.

  12. Two Decades of Seismic Monitoring by WEBNET: Disclosing a Lifecycle of an Earthquake Swarm Zone

    NASA Astrophysics Data System (ADS)

    Fischer, T.; Horalek, J.; Cermakova, H.; Michalek, J.; Doubravova, J.; Bouskova, A.; Bachura, M.

    2014-12-01

    The area of West Bohemia/Vogtland in western Eger Rift is typified by earthquake swarm activity with maximum magnitudes not exceeding ML 5. The seismicity is dominated by the area near Novy Kostel where earthquakes cluster along a narrow and steeply dipping focal zone of 8 km length that strikes about N-S in the depth range 7-11 km. Detailed seismic monitoring has been carried out by the WEBNET seismic network since 1992. During that period earthquake swarms with several mainshocks exceeding magnitude level ML 3 took place in 2000, 2008 and 2011. These swarms were characteristic by episodic character where the activity of individual episodes overlapped in time and space. Interestingly, the rate of activity of individual swarms increased with each subsequent swarm; the 2000 swarm being the slowest and the 2011 swarm the most rapid one. In 2014 the character of seismicity has changed from a swarm-like activity to a mainshock-aftershock activity. Already three mainshocks has occurred since May 2014; the ML 3.6 event of May 24, the ML 4.5 event of May 31 and the ML 3.5 event of August 3. All these events were followed by a short aftershock sequence of one to four days duration. All three events exceeded the following aftershocks by more than one magnitude level and none of these mainshocks were preceded by foreshocks, which differentiates this activity from the preceding swarm seismicity. Interestingly, the hypocenters of the mentioned earthquake swarms and mainshock-aftershock sequences share a common fault zone and overlap significantly. We present detailed analysis of precise hypocenter locations and statistical characteristics of the activity in order to find the origin of different behavior of seismic activity, which results in either earthquake swarms or mainshock-aftershock activity.

  13. Seismic monitoring at Deception Island volcano (Antarctica): the 2010-2011 survey

    NASA Astrophysics Data System (ADS)

    Martín, R.; Carmona, E.; Almendros, J.; Serrano, I.; Villaseñor, A.; Galeano, J.

    2012-04-01

    As an example of the recent advances introduced in seismic monitoring of Deception Island volcano (Antarctica) during recent years, we describe the instrumental network deployed during the 2010-2011 survey by the Instituto Andaluz de Geofísica of University of Granada, Spain (IAG-UGR). The period of operation extended from December 19, 2010 to March 5, 2011. We deployed a wireless seismic network composed by four three-component seismic stations. These stations are based on 24-bit SL04 SARA dataloggers sampling at 100 sps. They use a PC with embedded linux and SEISLOG data acquisition software. We use two types of three-component seismometers: short-period Mark L4C with natural frequency of 1 Hz and medium-period Lennartz3D/5s with natural frequency of 0.2 Hz. The network was designed for an optimum spatial coverage of the northern half of Deception, where a magma chamber has been reported. Station locations include the vicinity of the Spanish base "Gabriel de Castilla" (GdC), Obsidianas Beach, a zone near the craters from the 1970 eruptions, and the Chilean Shelter located south of Pendulum Cove. Continuous data from the local seismic network are received in real-time in the base by wifi transmission. We used Ubiquiti Networks Nanostation2 antennas with 2.4 GHz, dual-polarity, 10 dBi gain, and 54 Mbps transmission rate. They have shown a great robustness and speed for real-time applications. To prioritize data acquisition when the battery level is low, we have designed a circuit that allows independent power management for the seismic station and wireless transmission system. The reception antenna located at GdC is connected to a computer running SEISCOMP. This software supports several transmission protocols and manages the visualization and recording of seismic data, including the generation of summary plots to show the seismic activity. These twelve data channels are stored in miniseed format and displayed in real time, which allows for a rapid evaluation of

  14. Improved earthquake monitoring in the central and eastern United States in support of seismic assessments for critical facilities

    USGS Publications Warehouse

    Leith, William S.; Benz, Harley M.; Herrmann, Robert B.

    2011-01-01

    Evaluation of seismic monitoring capabilities in the central and eastern United States for critical facilities - including nuclear powerplants - focused on specific improvements to understand better the seismic hazards in the region. The report is not an assessment of seismic safety at nuclear plants. To accomplish the evaluation and to provide suggestions for improvements using funding from the American Recovery and Reinvestment Act of 2009, the U.S. Geological Survey examined addition of new strong-motion seismic stations in areas of seismic activity and addition of new seismic stations near nuclear power-plant locations, along with integration of data from the Transportable Array of some 400 mobile seismic stations. Some 38 and 68 stations, respectively, were suggested for addition in active seismic zones and near-power-plant locations. Expansion of databases for strong-motion and other earthquake source-characterization data also was evaluated. Recognizing pragmatic limitations of station deployment, augmentation of existing deployments provides improvements in source characterization by quantification of near-source attenuation in regions where larger earthquakes are expected. That augmentation also supports systematic data collection from existing networks. The report further utilizes the application of modeling procedures and processing algorithms, with the additional stations and the improved seismic databases, to leverage the capabilities of existing and expanded seismic arrays.

  15. Long-period Seismicity at the Napoleonville Salt Dome: Implications for Local Seismic Monitoring of Underground Hydrocarbon Storage Caverns

    NASA Astrophysics Data System (ADS)

    Dreger, D. S.; Ford, S. R.; Nayak, A.

    2015-12-01

    The formation of a large sinkhole at the Napoleonville salt dome, Assumption Parish, Louisiana, in August 2012 was accompanied by a rich sequence of complex seismic events, including long-period (LP) events that were recorded 11 km away at Transportable Array station 544A in White Castle, Louisiana. The LP events have relatively little energy at short periods, which make them difficult to detect using standard high-frequency power detectors, and the majority of energy that reaches the station is peaked near 0.4 Hz. The analysis of the local records reveals that the onset of the 0.4 Hz signals coincides with the S-wave arrival, and therefore it may be a shaking induced resonance in a fluid filled cavern. We created a low-frequency (0.1-0.6 Hz) power detector (short-term average / long-term average) that operated on all three components of the broadband instrument, since considerable energy was detected on the horizontal components. The detections from the power detector were then used as templates in three-channel correlation detectors thereby increasing the number of detections by a little more than a factor of two to nearly 3000. The rate of LP events is approximately one event every other day at the beginning of recording in March 2011. Around 2 May 2012 the rate changes to approximately 7 events per day and then increases to 25 events per day at the beginning of July 2012. Finally, in the days leading up to the sinkhole formation there are approximately 200 LP events per day. The analysis of these events could aid in the development of local seismic monitoring methods for underground industrial storage caverns. Prepared by LLNL under Contract DE-AC52-07NA27344.

  16. Training toward Advanced 3D Seismic Methods for CO2 Monitoring, Verification, and Accounting

    SciTech Connect

    Christopher Liner

    2012-05-31

    The objective of our work is graduate and undergraduate student training related to improved 3D seismic technology that addresses key challenges related to monitoring movement and containment of CO{sub 2}, specifically better quantification and sensitivity for mapping of caprock integrity, fractures, and other potential leakage pathways. We utilize data and results developed through previous DOE-funded CO{sub 2} characterization project (DE-FG26-06NT42734) at the Dickman Field of Ness County, KS. Dickman is a type locality for the geology that will be encountered for CO{sub 2} sequestration projects from northern Oklahoma across the U.S. midcontinent to Indiana and Illinois. Since its discovery in 1962, the Dickman Field has produced about 1.7 million barrels of oil from porous Mississippian carbonates with a small structural closure at about 4400 ft drilling depth. Project data includes 3.3 square miles of 3D seismic data, 142 wells, with log, some core, and oil/water production data available. Only two wells penetrate the deep saline aquifer. In a previous DOE-funded project, geological and seismic data were integrated to create a geological property model and a flow simulation grid. We believe that sequestration of CO{sub 2} will largely occur in areas of relatively flat geology and simple near surface, similar to Dickman. The challenge is not complex geology, but development of improved, lower-cost methods for detecting natural fractures and subtle faults. Our project used numerical simulation to test methods of gathering multicomponent, full azimuth data ideal for this purpose. Our specific objectives were to apply advanced seismic methods to aide in quantifying reservoir properties and lateral continuity of CO{sub 2} sequestration targets. The purpose of the current project is graduate and undergraduate student training related to improved 3D seismic technology that addresses key challenges related to monitoring movement and containment of CO{sub 2

  17. Monitoring Induced Seismicity with AE Sensors : The Influence of Unknown Calibration Functions

    NASA Astrophysics Data System (ADS)

    Plenkers, Katrin; Kwiatek, Grzegorz; Krüger, Frank

    2013-04-01

    We study the effect that an uncalibrated acoustic-emission (AE) sensor has on amplitude and magnitude using data of the JAGUARS project. The JAGUARS project recorded mining-induced seismicity in Mponeng Gold mine in Carletonville, South Africa in the frequency range 1 kHz < f < 180 kHz combining AE-sensors and accelerometers. Advanced monitoring of induced seismicity in underground structures sometimes includes today the use of high-frequency (f >> 1 kHz) AE monitoring systems. High-frequency monitoring allows the detection of seismic fractures on the centimeter scale and provides therefore important information about the migration of instabilities in the rock. Whereas the temporal-spatial analysis of seismic events recorded with AE sensors provides stable results, the analysis of source parameters including the estimation of magnitudes remains more challenging, because AE sensors are normally not well calibrated and exploit resonance frequencies to allow for high sensitivity. In our study the AE sensors are first calibrated in the frequency range 1kHz to 17 kHz relative to the well calibrated accelerometer. The calibration is possible due to the close employment of both sensor types, which allows to extract the sensor response (including the coupling effect) using signal deconvolution. We estimate three main resonance frequencies at about 2.5 kHz, 6 kHz and 10 kHz. Furthermore we calculate the directivity effect of the AE-sensor that influences the amplitude of the signal by up to - 15 dB. Second, we calculate the effect of the instrument response on the amplitude and the calculation of magnitude by studying synthetic data. We show the significant uncertainty that is introduced owing to the AE sensor response and conclude that source parameters often have high uncertainties and are not reliable for statistcal analsis if the instrument response of the recording AE sensor is not known.

  18. Monitoring transient changes within overpressured regions of subduction zones using ambient seismic noise.

    PubMed

    Chaves, Esteban J; Schwartz, Susan Y

    2016-01-01

    In subduction zones, elevated pore fluid pressure, generally linked to metamorphic dehydration reactions, has a profound influence on the mechanical behavior of the plate interface and forearc crust through its control on effective stress. We use seismic noise-based monitoring to characterize seismic velocity variations following the 2012 Nicoya Peninsula, Costa Rica earthquake [M w (moment magnitude) 7.6] that we attribute to the presence of pressurized pore fluids. Our study reveals a strong velocity reduction (~0.6%) in a region where previous work identified high forearc pore fluid pressure. The depth of this velocity reduction is constrained to be below 5 km and therefore not the result of near-surface damage due to strong ground motions; rather, we posit that it is caused by fracturing of the fluid-pressurized weakened crust due to dynamic stresses. Although pressurized fluids have been implicated in causing coseismic velocity reductions beneath the Japanese volcanic arc, this is the first report of a similar phenomenon in a subduction zone setting. It demonstrates the potential to identify pressurized fluids in subduction zones using temporal variations of seismic velocity inferred from ambient seismic noise correlations. PMID:26824075

  19. Monitoring transient changes within overpressured regions of subduction zones using ambient seismic noise

    PubMed Central

    Chaves, Esteban J.; Schwartz, Susan Y.

    2016-01-01

    In subduction zones, elevated pore fluid pressure, generally linked to metamorphic dehydration reactions, has a profound influence on the mechanical behavior of the plate interface and forearc crust through its control on effective stress. We use seismic noise–based monitoring to characterize seismic velocity variations following the 2012 Nicoya Peninsula, Costa Rica earthquake [Mw (moment magnitude) 7.6] that we attribute to the presence of pressurized pore fluids. Our study reveals a strong velocity reduction (~0.6%) in a region where previous work identified high forearc pore fluid pressure. The depth of this velocity reduction is constrained to be below 5 km and therefore not the result of near-surface damage due to strong ground motions; rather, we posit that it is caused by fracturing of the fluid-pressurized weakened crust due to dynamic stresses. Although pressurized fluids have been implicated in causing coseismic velocity reductions beneath the Japanese volcanic arc, this is the first report of a similar phenomenon in a subduction zone setting. It demonstrates the potential to identify pressurized fluids in subduction zones using temporal variations of seismic velocity inferred from ambient seismic noise correlations. PMID:26824075

  20. Monitoring changes in seismic velocity related to an ongoing rapid inflation event at Okmok volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Bennington, Ninfa L.; Haney, Matthew; De Angelis, Silvio; Thurber, Clifford H.; Freymueller, Jeffrey

    2015-08-01

    Okmok is one of the most active volcanoes in the Aleutian Arc. In an effort to improve our ability to detect precursory activity leading to eruption at Okmok, we monitor a recent, and possibly ongoing, GPS-inferred rapid inflation event at the volcano using ambient noise interferometry (ANI). Applying this method, we identify changes in seismic velocity outside of Okmok's caldera, which are related to the hydrologic cycle. Within the caldera, we observe decreases in seismic velocity that are associated with the GPS-inferred rapid inflation event. We also determine temporal changes in waveform decorrelation and show a continual increase in decorrelation rate over the time associated with the rapid inflation event. The magnitude of relative velocity decreases and decorrelation rate increases are comparable to previous studies at Piton de la Fournaise that associate such changes with increased production of volatiles and/or magmatic intrusion within the magma reservoir and associated opening of fractures and/or fissures. Notably, the largest decrease in relative velocity occurs along the intrastation path passing nearest to the center of the caldera. This observation, along with equal amplitude relative velocity decreases revealed via analysis of intracaldera autocorrelations, suggests that the inflation source may be located approximately within the center of the caldera and represent recharge of shallow magma storage in this location. Importantly, there is a relative absence of seismicity associated with this and previous rapid inflation events at Okmok. Thus, these ANI results are the first seismic evidence of such rapid inflation at the volcano.

  1. Monitoring changes in seismic velocity related to an ongoing rapid inflation event at Okmok volcano, Alaska

    USGS Publications Warehouse

    Bennington, Ninfa; Haney, Matt; De Angelis, Silvio; Thurber, Clifford; Freymueller, Jeff

    2015-01-01

    Okmok is one of the most active volcanoes in the Aleutian Arc. In an effort to improve our ability to detect precursory activity leading to eruption at Okmok, we monitor a recent, and possibly ongoing, GPS-inferred rapid inflation event at the volcano using ambient noise interferometry (ANI). Applying this method, we identify changes in seismic velocity outside of Okmok’s caldera, which are related to the hydrologic cycle. Within the caldera, we observe decreases in seismic velocity that are associated with the GPS-inferred rapid inflation event. We also determine temporal changes in waveform decorrelation and show a continual increase in decorrelation rate over the time associated with the rapid inflation event. Themagnitude of relative velocity decreases and decorrelation rate increases are comparable to previous studies at Piton de la Fournaise that associate such changes with increased production of volatiles and/ormagmatic intrusion within the magma reservoir and associated opening of fractures and/or fissures. Notably, the largest decrease in relative velocity occurs along the intrastation path passing nearest to the center of the caldera. This observation, along with equal amplitude relative velocity decreases revealed via analysis of intracaldera autocorrelations, suggests that the inflation sourcemay be located approximately within the center of the caldera and represent recharge of shallow magma storage in this location. Importantly, there is a relative absence of seismicity associated with this and previous rapid inflation events at Okmok. Thus, these ANI results are the first seismic evidence of such rapid inflation at the volcano.

  2. Feasibility of time-lapse AVO and AVOA analysis to monitor compaction-induced seismic anisotropy

    NASA Astrophysics Data System (ADS)

    He, Y.-X.; Angus, D. A.; Yuan, S. Y.; Xu, Y. G.

    2015-11-01

    Hydrocarbon reservoir production generally results in observable time-lapse physical property changes, such as velocity increases within a compacting reservoir. However, the physical property changes that lead to velocity changes can be difficult to isolate uniquely. Thus, integrated hydro-mechanical simulation, stress-sensitive rock physics models and time-lapse seismic modelling workflows can be employed to study the influence of velocity changes and induced seismic anisotropy due to reservoir compaction. We study the influence of reservoir compaction and compartmentalization on time-lapse seismic signatures for reflection amplitude variation with offset (AVO) and azimuth (AVOA). Specifically, the time-lapse AVO and AVOA responses are predicted for two models: a laterally homogeneous four-layer dipping model and a laterally heterogeneous graben structure reservoir model. Seismic reflection coefficients for different offsets and azimuths are calculated for compressional (P-P) and converted shear (P-S) waves using an anisotropic ray tracer as well as using approximate equations for AVO and AVOA. The simulations help assess the feasibility of using time-lapse AVO and AVOA signatures to monitor reservoir compartmentalization as well as evaluate induced stress anisotropy due to changes in the effective stress field. The results of this study indicate that time-lapse AVO and AVOA analysis can be applied as a potential means for qualitatively and semi-quantitatively linking azimuthal anisotropy changes caused by reservoir production to pressure/stress changes.

  3. Probabilistic Reasoning Over Seismic Time Series: Volcano Monitoring by Hidden Markov Models at Mt. Etna

    NASA Astrophysics Data System (ADS)

    Cassisi, Carmelo; Prestifilippo, Michele; Cannata, Andrea; Montalto, Placido; Patanè, Domenico; Privitera, Eugenio

    2016-07-01

    From January 2011 to December 2015, Mt. Etna was mainly characterized by a cyclic eruptive behavior with more than 40 lava fountains from New South-East Crater. Using the RMS (Root Mean Square) of the seismic signal recorded by stations close to the summit area, an automatic recognition of the different states of volcanic activity (QUIET, PRE-FOUNTAIN, FOUNTAIN, POST-FOUNTAIN) has been applied for monitoring purposes. Since values of the RMS time series calculated on the seismic signal are generated from a stochastic process, we can try to model the system generating its sampled values, assumed to be a Markov process, using Hidden Markov Models (HMMs). HMMs analysis seeks to recover the sequence of hidden states from the observations. In our framework, observations are characters generated by the Symbolic Aggregate approXimation (SAX) technique, which maps RMS time series values with symbols of a pre-defined alphabet. The main advantages of the proposed framework, based on HMMs and SAX, with respect to other automatic systems applied on seismic signals at Mt. Etna, are the use of multiple stations and static thresholds to well characterize the volcano states. Its application on a wide seismic dataset of Etna volcano shows the possibility to guess the volcano states. The experimental results show that, in most of the cases, we detected lava fountains in advance.

  4. Monitoring transient changes within overpressured regions of subduction zones using ambient seismic noise.

    PubMed

    Chaves, Esteban J; Schwartz, Susan Y

    2016-01-01

    In subduction zones, elevated pore fluid pressure, generally linked to metamorphic dehydration reactions, has a profound influence on the mechanical behavior of the plate interface and forearc crust through its control on effective stress. We use seismic noise-based monitoring to characterize seismic velocity variations following the 2012 Nicoya Peninsula, Costa Rica earthquake [M w (moment magnitude) 7.6] that we attribute to the presence of pressurized pore fluids. Our study reveals a strong velocity reduction (~0.6%) in a region where previous work identified high forearc pore fluid pressure. The depth of this velocity reduction is constrained to be below 5 km and therefore not the result of near-surface damage due to strong ground motions; rather, we posit that it is caused by fracturing of the fluid-pressurized weakened crust due to dynamic stresses. Although pressurized fluids have been implicated in causing coseismic velocity reductions beneath the Japanese volcanic arc, this is the first report of a similar phenomenon in a subduction zone setting. It demonstrates the potential to identify pressurized fluids in subduction zones using temporal variations of seismic velocity inferred from ambient seismic noise correlations.

  5. Planning the improvement of seismic monitoring in a volcanic supersite: experience on Mt. Etna

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Antonino; Scarfi, Luciano; Scaltrito, Antonio; Aiesi, Giampiero; Di Prima, Sergio; Ferrari, Ferruccio; Rapisarda, Salvatore

    2013-04-01

    Etna is one of the most active volcanoes in the world and one of the most intriguing natural laboratories for the understanding of eruptive processes and lava uprising in basalt-type volcanic environments; indeed, it is considered, by the scientific international community, together with the Vesuvius and the Hawaiian Islands, as a volcanic supersite. Its activity is continuously monitored by the Osservatorio Etneo of the Istituto Nazionale di Geofisica e Vulcanologia (INGV), by means of an array of integrated multidisciplinary techniques. In particular, Etna seismicity is recorded by a dense local seismic network (ESN- Etna Seismic Network), which, nowadays, consists of about 40 real-time seismic stations, many of which equipped with broadband velocity and accelerometer sensors. The data are analyzed routinely in detail by the Osservatorio Etneo staff, producing daily and periodic reports and bulletins of the earthquakes located in the whole Sicily and southern Calabria region. In the last decades, seismological observations provided important information on both the dynamics and internal structure of the volcano, in addition to their interaction with the regional tectonic structures. In the last year, in the framework of the VULCAMED project, an INGV workgroup has taken on the task of developing the existing seismic network through the installation of new measurement stations. By considering the spatial distribution of earthquakes in the area, the presence of structures known as seismically active and through extensive geological-geophysical surveys, ten potential new sites were identified. In the following months, some of these sites will complement the existing network. The choice of optimal sites must clearly be made through a careful analysis of environmental noise, of the possible logistics, technical and broadcast problems, but must also take into account the geometry of the existing seismic network. For this purpose, we applied the Seismic Network

  6. Feasibility of Monitoring Rock Fall in Yosemite Valley using Seismic Methods

    SciTech Connect

    Myers, S; Rock, D; Mayeda, K

    2000-03-02

    Public awareness of rock-fall hazard in Yosemite Valley has heightened after events in 1996 and 1999. Reports of audible blasts prior to rock-fall events suggest that rock cracking may in some instances precede the detachment a block from the cliff face. Seismic methods may be used to detect and locate small, inaudible rock cracking events, resulting in a catalog that outlines active areas and quantifies the level of activity. In order to test the feasibility of monitoring rock-fall activity with seismic methods, the Test Yosemite Rock-Fall Network (TYRN) was operated in the late summer and fall of 1999. The TYRN included five stations in the vicinity of the 1999 rock fall events: 2 stations at the base of the cliff and 3 above. Location of events depends on an estimate of seismic-wave velocity. During the TYRN deployment, a septic tank near Glacier Point was demolished, allowing the velocity of seismic P-waves to be calibrated. P-wave velocity was found to be about 5.68 km/s. Recordings of the explosion also allow assessment of arrival time precision, which controls the precision of seismic locations. Explosion recordings suggest that P-waves can be picked with a precision of about 0.005 seconds, suggesting that a seismic monitoring system would be able to locate events on the cliff face with sufficient precision to be useful in rock-fall monitoring. We used the amplitude of seismic noise recorded on the test network to determine the smallest event likely to be detected by the TYRN . An event with equivalent earthquake magnitude of -2.6 would be detectable at a sufficient number of stations to afford a location. This magnitude is equivalent to about 1.8 centimeters of slip on a surface with area of 1 square meter. Smaller displacements would be detectable for larger slip surfaces. The vast majority of events recorded on the TYRN were from the Mammoth Lakes region. About 5 to 6 events from the Mammoth Lakes area were recorded per day, but considerably more events

  7. Comprehensive seismic monitoring of the Cascadia megathrust with real-time GPS

    NASA Astrophysics Data System (ADS)

    Melbourne, T. I.; Szeliga, W. M.; Santillan, V. M.; Scrivner, C. W.; Webb, F.

    2013-12-01

    We have developed a comprehensive real-time GPS-based seismic monitoring system for the Cascadia subduction zone based on 1- and 5-second point position estimates computed within the ITRF08 reference frame. A Kalman filter stream editor that uses a geometry-free combination of phase and range observables to speed convergence while also producing independent estimation of carrier phase biases and ionosphere delay pre-cleans raw satellite measurements. These are then analyzed with GIPSY-OASIS using satellite clock and orbit corrections streamed continuously from the International GNSS Service (IGS) and the German Aerospace Center (DLR). The resulting RMS position scatter is less than 3 cm, and typical latencies are under 2 seconds. Currently 31 coastal Washington, Oregon, and northern California stations from the combined PANGA and PBO networks are analyzed. We are now ramping up to include all of the remaining 400+ stations currently operating throughout the Cascadia subduction zone, all of which are high-rate and telemetered in real-time to CWU. These receivers span the M9 megathrust, M7 crustal faults beneath population centers, several active Cascades volcanoes, and a host of other hazard sources. To use the point position streams for seismic monitoring, we have developed an inter-process client communication package that captures, buffers and re-broadcasts real-time positions and covariances to a variety of seismic estimation routines running on distributed hardware. An aggregator ingests, re-streams and can rebroadcast up to 24 hours of point-positions and resultant seismic estimates derived from the point positions to application clients distributed across web. A suite of seismic monitoring applications has also been written, which includes position time series analysis, instantaneous displacement vectors, and peak ground displacement contouring and mapping. We have also implemented a continuous estimation of finite-fault slip along the Cascadia megathrust

  8. Crosshole shear-wave seismic monitoring of an in situ air stripping waste remediation process

    SciTech Connect

    Elbring, G.J.

    1992-02-01

    Crosshole shear-wave seismic surveys have been used to monitor the distribution of injected air in the subsurface during an in situ air stripping waste remediation project at the Savannah River site in South Carolina. To remove the contaminant, in this case TCE's from a leaking sewer line, two horizontal wells were drilled at depths of 20 m and 52 m. Air was pumped into the lower well and a vacuum was applied to the upper well to extract the injected air. As the air passed through the subsurface, TCE's were dissolved into the gas and brought out the extraction well. Monitoring of the air injection by crosshole shear wave seismics is feasible due to the changes in soil saturation during injection resulting in a corresponding change in seismic velocities. Using a downhole shear-wave source and clamped downhole receiver, two sets of shear-wave data were taken. The first data were taken before the start of air injection, and the second taken during. The difference in travel times between the two data sets were tomographically inverted to obtain velocity differences. Velocity changes ranging up to 3% were mapped corresponding to saturation changes up to 24%. The distribution of these changes shows a desaturation around the position of the injection well with a plume extending in the direction of the extraction well. Layers with higher clay content show distinctively less change in saturation than the regions with higher sand content.

  9. Crosshole shear-wave seismic monitoring of an in situ air stripping waste remediation process

    SciTech Connect

    Elbring, G.J.

    1992-02-01

    Crosshole shear-wave seismic surveys have been used to monitor the distribution of injected air in the subsurface during an in situ air stripping waste remediation project at the Savannah River site in South Carolina. To remove the contaminant, in this case TCE`s from a leaking sewer line, two horizontal wells were drilled at depths of 20 m and 52 m. Air was pumped into the lower well and a vacuum was applied to the upper well to extract the injected air. As the air passed through the subsurface, TCE`s were dissolved into the gas and brought out the extraction well. Monitoring of the air injection by crosshole shear wave seismics is feasible due to the changes in soil saturation during injection resulting in a corresponding change in seismic velocities. Using a downhole shear-wave source and clamped downhole receiver, two sets of shear-wave data were taken. The first data were taken before the start of air injection, and the second taken during. The difference in travel times between the two data sets were tomographically inverted to obtain velocity differences. Velocity changes ranging up to 3% were mapped corresponding to saturation changes up to 24%. The distribution of these changes shows a desaturation around the position of the injection well with a plume extending in the direction of the extraction well. Layers with higher clay content show distinctively less change in saturation than the regions with higher sand content.

  10. Proceedings of the 23rd Seismic Research Symposium: Worldwide Monitoring of Nuclear Explosions

    SciTech Connect

    Warren, N. Jill; Chavez, Francesca C.

    2001-10-02

    These proceedings contain papers prepared for the 23rd Seismic Research Review: Worldwide Monitoring of Nuclear Explosions, held 2-5 October, 2001 in Jackson Hole, Wyoming. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), Air Force Technical Applications Center (AFTAC), the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  11. Real-time fracture monitoring in Engineered Geothermal Systems with seismic waves

    SciTech Connect

    Jose A. Rial; Jonathan Lees

    2009-03-31

    As proposed, the main effort in this project is the development of software capable of performing real-time monitoring of micro-seismic activity recorded by an array of sensors deployed around an EGS. The main milestones are defined by the development of software to perform the following tasks: • Real-time micro-earthquake detection and location • Real-time detection of shear-wave splitting • Delayed-time inversion of shear-wave splitting These algorithms, which are discussed in detail in this report, make possible the automatic and real-time monitoring of subsurface fracture systems in geothermal fields from data collected by an array of seismic sensors. Shear wave splitting (SWS) is parameterized in terms of the polarization of the fast shear wave and the time delay between the fast and slow shear waves, which are automatically measured and stored. The measured parameters are then combined with previously measured SWS parameters at the same station and used to invert for the orientation (strike and dip) and intensity of cracks under that station. In addition, this grant allowed the collection of seismic data from several geothermal regions in the US (Coso) and Iceland (Hengill) to use in the development and testing of the software.

  12. Proceedings of the 24th Seismic Research Review: Nuclear Explosion Monitoring: Innovation and Integration

    SciTech Connect

    Warren, N. Jill

    2002-09-17

    These proceedings contain papers prepared for the 24th Seismic Research Review: Nuclear Explosion Monitoring: Innovation and Integration, held 17-19 September, 2002 in Ponte Vedra Beach, Florida. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  13. Proceedings of the 27th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    SciTech Connect

    Wetovsky, Marvin A.; Benson, Jody; Patterson, Eileen F.

    2005-09-20

    These proceedings contain papers prepared for the 27th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 20-22 September, 2005 in Rancho Mirage, California. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  14. Proceedings of the 25th Seismic Research Review -- Nuclear Explosion Monitoring: Building the Knowledge Base

    SciTech Connect

    Chavez, Francesca C.; Mendius, E. Louise

    2003-09-23

    These proceedings contain papers prepared for the 25th Seismic Research Review -- Nuclear Explosion Monitoring: Building the Knowledge Base, held 23-25 September, 2003 in Tucson, Arizona. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  15. Proceedings of the 26th Seismic Research Review: Trends in Nuclear Explosion Monitoring

    SciTech Connect

    Chavez, Francesca C; Benson, Jody; Hanson, Stephanie; Mark, Carol; Wetovsky, Marvin A

    2004-09-21

    These proceedings contain papers prepared for the 26th Seismic Research Review: Trends in Nuclear Explosion Monitoring, held 21-23 September, 2004 in Orlando, Florida. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  16. Proceedings of the 28th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    SciTech Connect

    Wetovsky, Marvin A.; Benson, Jody; Patterson, Eileen F.

    2006-09-19

    These proceedings contain papers prepared for the 28th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 19-21 September, 2006 in Orlando, Florida. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  17. Three-axis accelerometer package for slimhole and microhole seismic monitoring and surveys

    SciTech Connect

    Hunter, S.L.; Harben, P.E.

    1997-01-07

    The development of microdrilling technology, nominally defined as drilling technology for 1-in.-diameter boreholes, shows potential for reducing the cost of drilling monitoring wells. A major question that arises in drilling microholes is if downhole logging and monitoring in general--and downhole seismic surveying in particular--can be conducted in such small holes since the inner working diameter of such a seismic tool could be as small as 0.31 in. A downhole three-component accelerometer package that fits within a 031-in. inner diameter tube has been designed, built, and tested. The package consists of three orthogonally mounted Entran EGA-125-5g piezoresistive silicon micromachined accelerometers with temperature compensation circuitry, downhole amplification, and line drivers mounted in a thin-walled aluminum tube. Accelerometers are commercially available in much smaller package sizes than conventional geophones, but the noise floor is significantly higher than that for the geophones. Cross-well tests using small explosives showed good signal-to-noise ratio in the recorded waveform at various receiver depths with a 1,50-ft source-receiver well separation. For some active downhole surveys, the accelerometer unit would clearly be adequate. It can be reasonably assumed, however, that for less energetic sources and for greater well separations, the high accelerometer noise floor is not acceptable. By expanding the inner working diameter of a microhole seismic tool to 0.5 in., other commercial accelerometers can be used with substantially lower noise floors.

  18. Time-lapse crosswell seismic and VSP monitoring of injected CO2 ina brine aquifer

    SciTech Connect

    Daley, Thomas M.; Myer, Larry R.; Peterson, J.E.; Majer, E.L.; Hoversten,G.M.

    2006-05-30

    Seismic surveys successfully imaged a small scale C02injection (1,600 tons) conducted in a brine aquifer of the Frio Formationnear Houston, Texas. These time-lapse bore-hole seismic surveys,crosswell and vertical seismic profile (VSP), were acquired to monitorthe C02 distribution using two boreholes (the new injection well and apre-existing well used for monitoring) which are 30 m apart at a depth of1500 m. The crosswell survey provided a high-resolution image of the C02distribution between the wells via tomographic imaging of the P-wavevelocity decrease (up to 500 mls). The simultaneously acquired S-wavetomography showed little change in S-wave velocity, as expected for fluidsubstitution. A rock physics model was used to estimate C02 saturationsof 10-20 percent from the P-wave velocity change. The VSP survey resolveda large (-70 percent) change in reflection amplitude for the Friohorizon. This C02 induced reflection amplitude change allowed estimationof the C02 extent beyond the monitor well and on 3 azimuths. The VSPresult is compared with numerical modeling of C02 saturations and isseismically modeled using the velocity change estimated in the crosswellsurvey.

  19. Seismic Monitoring and Post-Seismic Investigations following the 12 January 2010 Mw 7.0 Haiti Earthquake (Invited)

    NASA Astrophysics Data System (ADS)

    Altidor, J.; Dieuseul, A.; Ellsworth, W. L.; Given, D. D.; Hough, S. E.; Janvier, M. G.; Maharrey, J. Z.; Meremonte, M. E.; Mildor, B. S.; Prepetit, C.; Yong, A.

    2010-12-01

    We report on ongoing efforts to establish seismic monitoring in Haiti. Following the devastating M7.0 Haiti earthquake of 12 January 2010, the Bureau des Mines et de l’Energie worked with the U.S. Geological Survey and other scientific institutions to investigate the earthquake and to better assess hazard from future earthquakes. We deployed several types of portable instruments to record aftershocks: strong-motion instruments within Port-au-Prince to investigate the variability of shaking due to local geological conditions, and a combination of weak-motion, strong-motion, and broadband instruments around the Enriquillo-Plaintain Garden fault (EPGF), primarily to improve aftershock locations and to lower the magnitude threshold of aftershock recording. A total of twenty instruments were deployed, including eight RefTek instruments and nine strong-motion (K2) accelerometers deployed in Port-au-Prince in collaboration with the USGS, and three additional broadband stations deployed in the epicentral region in collaboration with the University of Nice. Five K2s have remained in operation in Port-au-Prince since late June; in late June two instruments were installed in Cap-Haitien and Port de Paix in northern Haiti to provide monitoring of the Septentrional fault. A permanent strong-motion (NetQuakes) instrument was deployed in late June at the US Embassy. Five additional NetQuakes instruments will be deployed by the BME in late 2010/early 2011. Addionally, the BME has collaborated with other scientific institutions, including Columbia University, the Institut Géophysique du Globe, University of Nice, the University of Texas at Austin, and Purdue University, to conduct other types of investigations. These studies include, for example, sampling of uplifted corals to establish a chronology of prior events in the region of the Enriquillo-Plantain Garden fault, surveys of geotechnical properties to develop microzonation maps of metropolitan Port-au-Prince, surveys of

  20. Oil Sands Characteristics and Time-Lapse and P-SV Seismic Steam Monitoring, Athabasca, Canada

    NASA Astrophysics Data System (ADS)

    Takahashi, A.; Nakayama, T.; Kashihara, K.; Skinner, L.; Kato, A.

    2008-12-01

    A vast amount of oil sands exists in the Athabasca area, Alberta, Canada. These oil sands consist of bitumen (extra-heavy oil) and unconsolidated sand distributed from surface to a depth of 750 meters. Including conventional crude oil, the total number of proved remaining oil reserves in Canada ranks second place in the world after Saudi Arabia. For the production of bitumen from the reservoir 200 to 500 meters in depth, the Steam Assisted Gravity Drainage (SAGD) method (Steam Injection EOR) has been adopted as bitumen is not movable at original temperatures. It is essential to understand the detailed reservoir distribution and steam chamber development extent for optimizing the field development. Oil sands reservoir characterization is conducted using 3D seismic data acquired in February 2002. Conducting acoustic impedance inversion to improve resolution and subsequent multi-attribute analysis integrating seismic data with well data facilitates an understanding of the detailed reservoir distribution. These analyses enable the basement shale to be imaged, and enables identification to a certain degree of thin shale within the reservoir. Top and bottom depths of the reservoir are estimated in the range of 2.0 meters near the existing wells even in such a complex channel sands environment characterized by abrupt lateral sedimentary facies changes. In March 2006, monitoring 3D seismic data was acquired to delineate steam-affected areas. The 2002 baseline data is used as a reference data and the 2006 monitoring data is calibrated to the 2002 seismic data. Apparent differences in the two 3D seismic data sets with the exception of production related response changes are removed during the calibration process. P-wave and S-wave velocities of oil sands core samples are also measured with various pressures and temperatures, and the laboratory measurement results are then combined to construct a rock physics model used to predict velocity changes induced by steam

  1. Seismic monitoring of roadbeds for traffic flow, vehicle characterization, and pavement deterioration

    SciTech Connect

    Elbring, G.J.; Ormesher, R.C.; Holcomb, D.J.

    1998-01-01

    A road-side seismic monitoring system has been developed that includes not only instrumentation and fielding methods, but also data analysis methods and codes. The system can be used as either a passive or active monitoring system. In the passive mode, seismic signals generated by passing vehicles are recorded. Analysis of these signals provides information on the location, speed, length, and weight of the vehicle. In the active mode, designed for monitoring pavement degradation, a vibrating magnetostrictive source is coupled to the shoulder of the road and signals generated are recorded on the opposite side of the road. Analysis of the variation in surface wave velocity at various frequencies (dispersion) is used in an attempt to develop models of the near-surface pavement velocity structure. The monitoring system was tested at two sites in New Mexico, an older two-lane road and a newly-paved section of interstate highway. At the older site, the system was able to determine information about vehicle velocity, wheel-base length and weight. The sites showed significant differences in response and the results indicate the need for further development of the method to extract the most information possible for each site investigated.

  2. Geospatial and In-Situ Monitoring Data for Seismic Hazard Assessment in Vrancea Area, Romania

    NASA Astrophysics Data System (ADS)

    Zoran, Maria

    Seismic hazard for almost half of the Romanian territory is determined by the Vrancea ac-tive seismic region, placed beneath the southern Carpathian Arc in Romania at conjunction of four tectonic blocks, which lie on the edge of the Eurasian plate. Vrancea zone is considered one of the most seismically active area in Europe, being characterized by strong intermediate depth seismicity in a very limited and well defined hypocentral region.Space-time anomalies of Earth's emitted radiation (radon in underground water and soil , thermal infrared in spec-tral range measured from satellite months to weeks before the occurrence of earthquakes etc.), ionospheric and electromagnetic anomalies have been interpreted, by several authors, as pre-seismic signals.Satellite remote sensing provides a systematic, synoptic framework for advancing scientific knowledge of the Earth complex system of geophysical phenomena which often lead to seismic hazards. Space-based geodetic measurements of the solid Earth with the Global Positioning System, combined with ground-based seismological measurements and satellite re-mote sensing information are yielding the principal data for modeling lithospheric processes and for accurately estimating the distribution of potentially damaging strong ground motions which is critical for earthquake engineering applications. Moreover, integrated with interfero-metric synthetic aperture radar, these measurements provide spatially continuous observations of deformation with sub-centimeter accuracy. Seismic and in situ monitoring, geodetic mea-surements, high-resolution digital elevation models (e.g. from InSAR, IKONOS and digital photogrammetry) and imaging spectroscopy (e.g. using ASTER, MODIS and Hyperion) are contributing significantly to seismic hazard risk assessment by revealing new insights in the understanding of the kinematics and dynamics of the complex plate boundary system and long-term deformation in relation with earthquake activity. Several

  3. Stress-strain sensor for monitoring seismic precursors and fault activities in the sand

    NASA Astrophysics Data System (ADS)

    Du, Qiujiao; Sun, Wei; Zeng, Zuoxun

    2016-04-01

    In this paper, a sensor to monitor stress-strain signals in a granular medium is used to detect seismic precursory information. Compared with the widely used sensors of borehole stress in the rock, the sensor has more convenient operation, higher output sensitivity, compactness and farther propagation effect. The stress and strain changes before Pu'er Ms6.4 earthquake in China are recorded by Beijing and Xinmin stations, and its corresponding fault activities are analyzed. Study indicates anomalous amplitude of strain signal reaches 10 times higher than that of ordinary background, and compressive oscillation and extensional oscillation occurred constantly before the earthquake. The method and results presented in the paper provide a new way for investigating seismic precursors for shallow-source earthquakes.

  4. Seismic monitoring results from the first 6 months of CO2 injection at the Aquistore geological storage site, Saskatchewan, Canada

    NASA Astrophysics Data System (ADS)

    Daley, T. M.; White, D. J.; Stork, A.; Schmitt, D. R.; Worth, K.; Harris, K.; Roberts, B.; Samson, C.; Kendal, M. J.

    2015-12-01

    The Aquistore Project, located in SE Saskatchewan, Canada, is a demonstration project for CO2 storage in a deep saline aquifer. CO2 captured from a nearby coal-fired power plant is being injected into a brine-filled sandstone formation at 3100-3300 m depth. CO2 injection commenced in April, 2015, at initial rates of up to 250 tonnes per day. Seismic monitoring methods have been employed to track the subsurface CO2 plume and to record any injection-induced microseismicity. Active seismic methods utilized include 4D surface seismics using a sparse permanent array, 4D vertical seismic profiles (VSP) with both downhole geophones and a fiber optic distributed acoustic sensor (DAS) system. Pre-injection baseline seismic surveys have established very good repeatability with NRMS values as low as 0.07. 3D finite-difference seismic modelling of fluid flow simulations is used with the repeatability estimates to determine the appropriate timing for the first CO2 monitor surveys. Time-lapse logging is being conducted on a regular basis to provide in situ measurement of the change in seismic velocity associated with changes in CO2 saturation. Continuous passive seismic recording has been ongoing since the summer of 2012 to establish background local seismicity prior to the start of CO2 injection. Passive monitoring is being conducted using two, 2.5 km long, orthogonal linear arrays of surface geophones.with 3-component short-period geophones, 3 broadband surface seismometers, and an array of 3-component short-period geophones in an observation well. No significant injection-related seismicity (Mw > -1) has been detected at the surface during the first 4 months of CO2 injection. On-going analysis of the downhole passive data will provide further information as to the occurrence of lower magnitude microseismicity (Mw of -1 to -3).

  5. Time Lapse Storey Building Early Monitoring Based on Rapid Seismic Response Analysis in Indonesia

    NASA Astrophysics Data System (ADS)

    Julius, A. M.

    2015-12-01

    Within the last decade, advances in the acquisition, processing and transmission of data from seismic monitoring has contributed to the growth in the number structures instrumented with such systems. An equally important factor for such growth can be attributed to the demands by stakeholders to find rapid answers to important questions related to the functionality or state of "health" of structures during and immediately of a seismic events. Consequently, this study aims to monitor the storey building based on seismic response i. e. earthquake and tremor analysis at short time lapse using accelerographs data. This study used one of storey building (X) in Jakarta city that suffered the effects of Kebumen earthquake January 25th 2014, Pandeglang earthquake July 9th 2014, and Lebak earthquake November 8th 2014. Tremors used in this study are tremors after the three following earthquakes. Data processing used to determine peak ground acceleration (PGA), peak ground velocity (PGV), peak ground displacement (PGD), spectral acceleration (SA), spectral velocity (SV), spectral displacement (SD), A/V ratio, acceleration amplification and effective duration (te). Then determine the natural frequency (f0) and peak of H/V ratio using H/V ratio method. The earthquakes data processing result shows the value of peak ground motion, spectrum response, A/V ratio and acceleration amplification increases with height, while the value of the effective duration decreases. Then, tremors data processing result one month after each earthquakes shows the natural frequency of building in constant value. Increasing of peak ground motion, spectrum response, A/V ratio, acceleration amplification, then decrease of effective duration following the increase of building floors shows that the building construction supports the increasing of shaking and strongly influenced by local site effect. The constant value of building natural frequency shows the building still in good performance. This

  6. Seismic dynamic monitoring in CO2 flooding based on characterization of frequency-dependent velocity factor

    NASA Astrophysics Data System (ADS)

    Zhang, Jun-Hua; Li, Jun; Xiao, Wen; Tan, Ming-You; Zhang, Yun-Ying; Cui, Shi-Ling; Qu, Zhi-Peng

    2016-06-01

    The phase velocity of seismic waves varies with the propagation frequency, and thus frequency-dependent phenomena appear when CO2 gas is injected into a reservoir. By dynamically considering these phenomena with reservoir conditions it is thus feasible to extract the frequency-dependent velocity factor with the aim of monitoring changes in the reservoir both before and after CO2 injection. In the paper, we derive a quantitative expression for the frequency-dependent factor based on the Robinson seismic convolution model. In addition, an inversion equation with a frequency-dependent velocity factor is constructed, and a procedure is implemented using the following four processing steps: decomposition of the spectrum by generalized S transform, wavelet extraction of cross-well seismic traces, spectrum equalization processing, and an extraction method for frequency-dependent velocity factor based on the damped least-square algorithm. An attenuation layered model is then established based on changes in the Q value of the viscoelastic medium, and spectra of migration profiles from forward modeling are obtained and analyzed. Frequency-dependent factors are extracted and compared, and the effectiveness of the method is then verified using a synthetic data. The frequency-dependent velocity factor is finally applied to target processing and oil displacement monitoring based on real seismic data obtained before and after CO2 injection in the G89 well block within Shengli oilfield. Profiles and slices of the frequency-dependent factor determine its ability to indicate differences in CO2 flooding, and the predicting results are highly consistent with those of practical investigations within the well block.

  7. Using Ambient Seismic Noise to Monitor Post-Seismic Relaxation After the 2010 Mw 7.1 Darfield Earthquake, New Zealand

    NASA Astrophysics Data System (ADS)

    Savage, M. K.; Heckels, R.; Townend, J.

    2015-12-01

    Quantifying seismic velocity changes following large earthquakes can provide insights into the crustal response of the earth. The use of ambient seismic noise to monitor these changes is becoming increasingly widespread. Cross-correlations of long-duration ambient noise records can be used to give stable impulse response functions without the need for repeated seismic events. Temporal velocity changes were detected in the four months following the September 2010 Mw 7.1 Darfield event in South Island, New Zealand, using temporary seismic networks originally deployed to record aftershocks in the region. The arrays consisted of stations lying on and surrounding the fault, with a maximum inter-station distance of 156km. The 2010-2011 Canterbury earthquake sequence occurred largely on previously unknown and buried faults. The Darfield earthquake was the first and largest in a sequence of events that hit the region, rupturing the Greendale Fault. A surface rupture of nearly 30km was observed. The sequence also included the Mw 6.3 February 2011 Christchurch event, which caused widespread damage throughout the city and resulted in almost 200 deaths. Nine-component, day-long Green's functions were computed for frequencies between 0.1 - 1.0 Hz for full waveform seismic data from immediately after the 4th September 2010 earthquake until mid-January 2011. Using the moving window cross-spectral method, stacks of daily functions covering the study period (reference functions), were compared to consecutive 10 day stacks of cross-correlations to measure time delays between them. These were then inverted for seismic velocity changes with respect to the reference functions. Over the study period an increase in seismic velocity of 0.25% ± 0.02% was determined proximal to the Greendale fault. These results are similar to studies in other regions, and we attribute the changes to post-seismic relaxation through crack-healing of the Greendale Fault and throughout the region.

  8. Experimental monitoring of the hydro-mechanical state of a discontinuity using controlled source seismic method

    NASA Astrophysics Data System (ADS)

    Place, Joachim; Blake, Oshaine; Rietbrock, Andreas; Faulkner, Dan

    2013-04-01

    Great earthquakes often occur in crystalline rocks, and basement rocks can host geothermal and hydrocarbon resources. In such rocks, the fluid storage and transfer properties depend mainly on the natural fault and fracture networks. Therefore, it is of primary importance to characterise the physical properties of the fault zones in order to better understand the seismogenic processes and how the resources can be exploited. Seismic waves are known to be sensitive to many parameters which evolve depending on the fault response to stresses and fluid type. Therefore seismic methods show a great potential to monitor the hydro-mechanical state of structures remotely, with no need for drilling through the structures. We developed a basic experimental approach at sample scale to monitor the mechanical coupling through a discontinuity between a granite sample in contact with a piece of steel, when the effective pressure (Peff) and the nature of the filling fluid vary. Piezoceramics utilised both as sources and sensors are located on the steel (in which the attenuation is assumed to be zero) and both generate and record the P and S wave fields reflected off the discontinuity at normal incidence. This permits the normal (Bn) and tangential (Bt) fracture compliances to be calculated after Schoenberg's linear slip theory from the measurement of P-P and S-S reflection coefficients. The roughness of the sample surface, as well as the effect of fluid type (air or water) and Peff were studied. Under dry conditions, it is observed that the poorer the contact area, the higher Bn and Bt, meaning that the seismic energy of P and S waves is less transmitted. Increasing the effective pressure decreases the compliances, which is interpreted as the effect of the closure of the voids at the interface; this permits more seismic energy to be transmitted through the interface. It is also observed that Bn is significantly higher than Bt at low Peff (<60 MPa). Under water saturated conditions

  9. Real-time seismic monitoring needs of a building owner - And the solution: A cooperative effort

    USGS Publications Warehouse

    Celebi, M.; Sanli, A.; Sinclair, M.; Gallant, S.; Radulescu, D.

    2004-01-01

    A recently implemented advanced seismic monitoring system for a 24-story building facilitates recording of accelerations and computing displacements and drift ratios in near-real time to measure the earthquake performance of the building. The drift ratio is related to the damage condition of the specific building. This system meets the owner's needs for rapid quantitative input to assessments and decisions on post-earthquake occupancy. The system is now successfully working and, in absence of strong shaking to date, is producing low-amplitude data in real time for routine analyses and assessment. Studies of such data to date indicate that the configured monitoring system with its building specific software can be a useful tool in rapid assessment of buildings and other structures following an earthquake. Such systems can be used for health monitoring of a building, for assessing performance-based design and analyses procedures, for long-term assessment of structural characteristics, and for long-term damage detection.

  10. Real-time seismic monitoring and functionality assessment of a building

    USGS Publications Warehouse

    Celebi, M.; ,

    2005-01-01

    This paper presents recent developments and approaches (using GPS technology and real-time double-integration) to obtain displacements and, in turn, drift ratios, in real-time or near real-time to meet the needs of the engineering and user community in seismic monitoring and assessing the functionality and damage condition of structures. Drift ratios computed in near real-time allow technical assessment of the damage condition of a building. Relevant parameters, such as the type of connections and story structural characteristics (including geometry) are used in computing drifts corresponding to several pre-selected threshold stages of damage. Thus, drift ratios determined from real-time monitoring can be compared to pre-computed threshold drift ratios. The approaches described herein can be used for performance evaluation of structures and can be considered as building health-monitoring applications.

  11. Laser- and Radar-based Mission Concepts for Suborbital and Spaceborne Monitoring of Seismic Surface Waves

    SciTech Connect

    Foxall, W; Schultz, C A; Tralli, D M

    2004-09-21

    The development of a suborbital or spaceborne system to monitor seismic waves poses an intriguing prospect for advancing the state of seismology. This capability would enable an unprecedented global mapping of the velocity structure of the earth's crust, understanding of earthquake rupture dynamics and wave propagation effects, and event source location, characterization and discrimination that are critical for both fundamental earthquake research and nuclear non-proliferation applications. As part of an ongoing collaboration between LLNL and JPL, an advanced mission concept study assessed architectural considerations and operational and data delivery requirements, extending two prior studies by each organization--a radar-based satellite system (JPL) for earthquake hazard assessment and a feasibility study of space- or UAV-based laser seismometer systems (LLNL) for seismic event monitoring. Seismic wave measurement requirements include lower bounds on detectability of specific seismic sources of interest and wave amplitude accuracy for different levels of analysis, such as source characterization, discrimination and tomography, with a 100 {micro}m wave amplitude resolution for waves nominally traveling 5 km/s, an upper frequency bound based on explosion and earthquake surface displacement spectra, and minimum horizontal resolution (1-5 km) and areal coverage, in general and for targeted observations. For a radar system, corresponding engineering and operational factors include: Radar frequency (dictated by required wave amplitude measurement accuracy and maximizing ranging, Doppler or interferometric sensitivity), time sampling (maximum seismic wave frequency and velocity), and overall system considerations such as mass, power and data rate. Technical challenges include characterization of, and compensation for, phase distortion resulting from atmospheric and ionospheric perturbations and turbulence, and effects of ground scattering characteristics and seismic

  12. DOE program on seismic characterization for regions of interest to CTBT monitoring

    SciTech Connect

    Ryall, A.S.; Weaver, T.A.

    1995-07-01

    The primary goal of the DOE programs on Geophysical Characterization of (1) the Middle East and North Africa (ME-NA) and (2) Southern Asia (SA) is to provide the Air Force Technical Applications Center (AFRAC) with the analytic tools and knowledge base to permit effective verification of Comprehensive Test Ban Treaty (CTBT) compliance in those regions. The program also aims at using these regionalizations as models for the development of a detailed prescription for seismic calibration and knowledge base compilation in areas where the US has had little or no previous monitoring experience. In any given region, the CTBT seismic monitoring system will depend heavily on a few key arrays and/or three-component stations, and it will be important to know as much as possible about the physical properties of the earth`s crust and upper mantle: (1) in the vicinity of these stations, (2) in areas of potential earthquake activity or commercial blasting in the region containing the stations, and (3) along the propagation path from the sources to the stations. To be able to discriminate between various source types, we will also need to know how well the various event characterization techniques perform when they are transported from one tectonic or geologic environment to another. The Department of Energy`s CMT R&D program plan (DOE, 1994), which includes the ME-NA and SA characterization programs, incorporates an iterative process that combines field experiments, computer modeling and data analysis for the development, testing, evaluation and modification of data processing algorithms as appropriate to achieve specific US monitoring objectives. This process will be applied to seismic event detection, location and identification.

  13. Development of Ocean Bottom Multi-component Seismic System for Methane Hydrate Dissociation Monitoring

    NASA Astrophysics Data System (ADS)

    Takahashi, H.; Asakawa, E.; Hayashi, T.; Inamori, T.; Saeki, T.

    2011-12-01

    A 2D multi-component seismic survey was carried out in the Nankai Trough using the RSCS (Real-time Seismic Cable System) system in 2006. The RSCS is the newly developed ocean bottom cable system which is usable in more than 2000m water depth. The results of the PP and data PS components gave us much information of the methane hydrates bearing zone. Based on RSCS technology, we are developing a new monitoring system using multi-component seismic sensors to delineate the methane hydrate dissociation zone for the offshore methane hydrate production test scheduled in FY2012. Conventional RSCS is composed of three component gimbaled geophones which require a large volume inside the receiver. We will adopt accelerometers to achieve a small receiver that is 2/3 the size of conventional RSCS. The accelerometer data can be corrected into horizontal or vertical directions based on the gravity acceleration. The receiver case has a protective metallic exterior and the cable is protected with steel-screened armoring, allowing for burial usage using ROV for sub-seabed deployment. It will realize a unique survey style that leaves the system on the seabed between pre-test baseline survey and post-test repeated survey, which might be up to 6 months. The fixed location of the receiver is very important for time-lapse monitoring survey. We name the new system as DSS (Deep-sea Seismic System). A feasibility study to detect the methane hydrate dissociation with the DSS was carried out and we found that the methane hydrate dissociation could be detected with the DSS depending on the area of the dissociation. The first experiment of the DSS performance test in a marine area is planned in November 2011. The main features of DSS are described as follows: (1) Deep-sea /Ultra Deep-sea Operation Methane hydrate exists in equilibrium temperature and pressure holds at water depths greater than 500m. The system water depth resistance target up to 2000m. The receiver case has a protective

  14. Enhancing Monitoring of Recharge-Related Environmental Remediation Processes Using Time-Lapse Seismic Refraction

    NASA Astrophysics Data System (ADS)

    Gaines, D. P.; Baker, G. S.; Hubbard, S. S.; Watson, D. B.; Jardine, P. M.

    2008-12-01

    The application of time-lapse seismic methods has typically been constrained to large-scale geologic investigations associated with petroleum exploration and exploitation; however, there is growing interest in monitoring near-surface phenomena (e.g., fluid flow in fractured or karstic geologic media, hydraulic recharge, and near-surface anthropogenic manipulations) using time-lapse seismic methods. In order to demonstrate the feasibility of detailed time-lapse seismic refraction tomography (TLSRT), we have monitored a perched water table at Oak Ridge National Laboratory (ORNL) Y-12 site in conjunction with a multi- disciplinary investigation of the fate and transport of contaminants. Due to remnant anthropogenic alterations of the site (i.e., replacement of 0-7 meters of contaminated soil with poorly sorted limestone gravel fill during construction of a seepage basin cap), the near surface hydrology is extremely complex and is hypothesized to have a large influence on infiltration, contaminant distribution, and contaminant remobilization. Understanding the impact of recharge-related flow and transport processes is especially important in regions that are subjected to significant precipitation events, such as at the ORNL Y-12 site. Here, TLSRT techniques are used to monitor the changing geometry of a perched water table located near the covered seepage basin, while coincident time-lapse surface electrical resistivity (TLERT) measurements are used to monitor changes in total dissolved solids due to recharge-related dilution. Data are collected at multiple time intervals (i.e., daily, weekly, monthly, yearly) and at varying stages in the evolution of the perch zone. The resulting seismic data are processed using wavepath eikonal tomography (WET) and differenced to identify areas of variable velocity associated with a change in saturation. The differenced tomograms correlate with discrete point water table measurements; however, the highly variable water table at this

  15. Passive seismic tomography application for cave monitoring in DOZ underground mine PT. Freeport Indonesia

    NASA Astrophysics Data System (ADS)

    Nurhandoko, Bagus Endar B.; Wely, Woen; Setiadi, Herlan; Riyanto, Erwin

    2015-04-01

    It is already known that tomography has a great impact for analyzing and mapping unknown objects based on inversion, travel time as well as waveform inversion. Therefore, tomography has used in wide area, not only in medical but also in petroleum as well as mining. Recently, tomography method is being applied in several mining industries. A case study of tomography imaging has been carried out in DOZ ( Deep Ore Zone ) block caving mine, Tembagapura, Papua. Many researchers are undergoing to investigate the properties of DOZ cave not only outside but also inside which is unknown. Tomography takes a part for determining this objective.The sources are natural from the seismic events that caused by mining induced seismicity and rocks deformation activity, therefore it is called as passive seismic. These microseismic travel time data are processed by Simultaneous Iterative Reconstruction Technique (SIRT). The result of the inversion can be used for DOZ cave monitoring. These information must be used for identifying weak zone inside the cave. In addition, these results of tomography can be used to determine DOZ and cave information to support mine activity in PT. Freeport Indonesia.

  16. Passive seismic tomography application for cave monitoring in DOZ underground mine PT. Freeport Indonesia

    SciTech Connect

    Nurhandoko, Bagus Endar B.; Wely, Woen; Setiadi, Herlan; Riyanto, Erwin

    2015-04-16

    It is already known that tomography has a great impact for analyzing and mapping unknown objects based on inversion, travel time as well as waveform inversion. Therefore, tomography has used in wide area, not only in medical but also in petroleum as well as mining. Recently, tomography method is being applied in several mining industries. A case study of tomography imaging has been carried out in DOZ ( Deep Ore Zone ) block caving mine, Tembagapura, Papua. Many researchers are undergoing to investigate the properties of DOZ cave not only outside but also inside which is unknown. Tomography takes a part for determining this objective.The sources are natural from the seismic events that caused by mining induced seismicity and rocks deformation activity, therefore it is called as passive seismic. These microseismic travel time data are processed by Simultaneous Iterative Reconstruction Technique (SIRT). The result of the inversion can be used for DOZ cave monitoring. These information must be used for identifying weak zone inside the cave. In addition, these results of tomography can be used to determine DOZ and cave information to support mine activity in PT. Freeport Indonesia.

  17. Effective seismic acceleration measurements for low-cost Structural Health Monitoring

    NASA Astrophysics Data System (ADS)

    Pentaris, Fragkiskos; Makris, John P.

    2015-04-01

    There is increasing demand on cost effective Structural Health Monitoring systems for buildings as well as important and/or critical constructions. The front end for all these systems is the accelerometer. We present a comparative study of two low cost MEMS accelaration sensors against a very sensitive, high dynamic range strong motion accelerometer of force balance type but much more expensive. A real experiment was realized by deploying the three sesnors in a reinforced concrete building of the premises of TEI of Crete at Chania Crete, an earthquake prone region. The analysis of the collected accelararion data from many seismic events indicates that all sensors are able to efficiently reveal the seismic response of the construction in terms of PSD. Furthermore, it is shown that coherence diagrams between excitation and response of the building under study, depict structural characteristics but also the seismic energy distribution. This work is supported by the Archimedes III Program of the Ministry of Education of Greece, through the Operational Program "Educational and Lifelong Learning", in the framework of the project entitled "Interdisciplinary Multi-Scale Research of Earthquake Physics and Seismotectonics at the front of the Hellenic Arc (IMPACT-ARC)" and is co-financed by the European Union (European Social Fund) and Greek national funds.

  18. Peaceful Nuclear Explosion Datasets for Seismic Research and Nuclear Test Monitoring

    NASA Astrophysics Data System (ADS)

    Smithson, S. B.; Morozov, I. B.; Morozova, E. A.; Richards, P. G.; Solodilov, L. N.

    2001-12-01

    Within the next four years, IRIS databases will receive from the University of Wyoming and GEON recordings from nine ultra-long range Deep Seismic Sounding (DSS) projects conducted between 1970-1989 in the former Soviet Union: QUARTZ, CRATON, KIMBERLITE, METEORITE, RIFT, RUBY, BATHOLIT, BAZALT, and AGATE. Jointly sponsored by the Department of Defense and National Science Foundation, this effort will bring the unique recordings of 22 Peaceful Nuclear Explosions (PNEs) and hundreds of crustal-scale chemical shots to the broad seismological and monitoring research communities. A grid of reversed PNE profiles (plus fan recording for RUBY) covers the East European Platform, the Ural Mountains, the West Siberian Platform, the Siberian craton, and the Baikal Rift. Dense, 3-component, short-period recordings along these profiles provide a valuable source of seismic information for seismic calibration of these vast aseismic regions. DSS recordings offer unique opportunities to study propagation effects of body waves and regional seismic phases, to examine their correlation with geologic and tectonic features, to develop unusually well constrained models of the structure of the crust and upper mantle to 600-700 km depth, and to explore the variability of explosion discriminants such as spectral ratios of P- and S-waves. Though the data principally concern properties of the crust and upper mantle, some of the profiles also show strong reflections from the core-mantle boundary. We summarize the recent findings from the analysis of PNE datasets in Northern Eurasia. These results include (1) unusually detailed velocity and attenuation structure of the crust and uppermost mantle, (2) characterization of crustal attenuation through coda measurements, (3) constraints on seismic scattering from within the crust and uppermost mantle, (4) detailed imaging of the crustal basement using receiver functions, (5) continuous observations of the regional phases from the PNEs within 0

  19. Subsurface Characterization and Seismic Monitoring for the Southwest Partnerships Phase III Demonstration Project at Farnsworth Field, TX

    NASA Astrophysics Data System (ADS)

    Will, R. A.; Balch, R. S.

    2015-12-01

    The Southwest Partnership on Carbon Sequestration is performing seismic based characterization and monitoring activities at an active CO2 EOR project at Farnsworth Field, Texas. CO2 is anthropogenically sourced from a fertilizer and an ethanol plant. The field has 13 CO2 injectors and has sequestered 302,982 metric tonnes of CO2 since October 2013. The field site provides an excellent laboratory for testing a range of monitoring technologies in an operating CO2 flood since planned development is sequential and allows for multiple opportunities to record zero CO2 baseline data, mid-flood data, and fully flooded data. The project is comparing and contrasting several scales of seismic technologies in order to determine best practices for large scale commercial sequestration projects. Characterization efforts include an 85 km2 3D surface seismic survey, baseline and repeat 3D VSP surveys centered on injection wells, cross-well tomography baseline and repeat surveys between injector/producer pairs, and a borehole passive seismic array to monitor induced seismicity. All surveys have contributed to detailed geologic models which were then used for fluid flow and risk assessment simulations. 3D VSP and cross-well data with repeat surveys have allowed for direct comparisons of the reservoir prior to CO2 injection and at eight months into injection, with a goal of imaging the CO2 plume as it moves away from injection wells. Additional repeat surveys at regular intervals will continue to refine the plume. The goal of this work is to demonstrate seismic based technologies to monitor CO2 sequestration projects, and to contribute to best practices manuals for commercial scale CO2 sequestration projects. In this talk the seismic plan will be outlined, progress towards goals enumerated, and preliminary results from baseline and repeat seismic data will be discussed. Funding for this project is provided by the U.S. Department of Energy under Award No. DE-FC26-05NT42591.

  20. Geoazur's contribution in instrumentation to monitor seismic activity of the Earth

    NASA Astrophysics Data System (ADS)

    Yates, B.; Hello, Y.; Anglade, A.; Desprez, O.; Ogé, A.; Charvis, P.; Deschamps, A.; Galve, A.; Nolet, G.; Sukhovich, A.

    2011-12-01

    Seismic activity in the earth is mainly located near the tectonic plate boundaries, in the deep ocean (expansion centers) or near their margins (subduction zones). Travel times and waveforms of recorded seismograms can be used to reconstruct the three-dimensional wave speed distribution in the earth with seismic tomography or to image specific boundaries in the deep earth. Because of the lack of permanent sea-bottom seismometers these observation are conducted over short period of time using portable ocean bottom seismometers. Geaozur has a long experience and strong skills in designing and deploying Ocean Bottom Seismometers all over the world. We have developed two types of ocean bottom instruments. The "Hippocampe" for long deployment and "Lady bug" for aftershock monitoring or for fast overlaps during wide angle experiments. Early warning systems for tsunamis and earthquakes have been developed in recent years but these need real time data transmission and direct control of the instrument. We have developed a permanent real time Broad Band instrument installed in the Mediterranean Sea and connected to the Antares Neutrinos telescope. This instrument offers all the advantages of a very heavy and costly installation, such as the ability to do real-time seismology on the seafloor. Such real-time seafloor monitoring is especially important for seismic hazard. Major earthquakes cause human and economic losses directly related to the strong motion of the ground or by induced phenomena such as tsunamis and landslides. Fiber optical cables provide a high-capacity lightweight alternative to traditional copper cables. Three-component sensors analyze permanently the noise signal and detect the events to record. Major events can force the network to transmit data with almost zero lag time. The optical link also allows us to retrieve events at a later date. However, OBSs alone can never provide the density and long term, homogeneous data coverage needed for local and global

  1. Preliminary study for active monitoring of the plate boundary using ACROSS: Synthetic and observed seismic records

    NASA Astrophysics Data System (ADS)

    Tsuruga, K.; Kasahara, J.; Hasada, Y.; Kunitomo, T.; Ikuta, R.; Watanabe, T.; Yamaoka, K.; Fujii, N.; Kumazawa, M.; Nagao, H.; Nakajima, T.; Saiga, A.; Satomura, M.

    2005-12-01

    ACROSS (Accurately-Controlled Routinely-Operated Signal System) has been developed for active monitoring of a dynamic state in the Earth's structure (Kumazawa et al., 2000). Since November 2004, we have conducted an array observation of ACROSS signals in Tokai area, central Japan, to identify any seismic reflection (and hopefully its temporal change) from the lower crust and/or subducting Philippine Sea plate (Kasahara et al., 2004). In this report, we show the recent results and discuss the relevance of several arrivals of wave groups to underground structures using the theoretical travel times and synthetic waveforms. The frequency-modulated ACROSS signals (10-20 Hz) have been continuously transmitted from the sources located in Toki city, central Japan (Kunitomo et al., 2005) and received at 22 temporal seismic stations at the offset distance of 40-75 km from the source. We define the transfer function between a source and a receiver as a nine-element second-order tensor, Hjk, where j and k denote directional components of the observed displacement and the excitation force, and r, t and v represent the radial, transverse and vertical components, respectively. We recognized the significant wave groups within the travel time ranges of 10-18 and of 15-23 seconds at 54-74 km offset distance through stacking the data for about 60 days. Such wave groups also appear on the records of a Hi-net station at 57.4km by stacking for 30 days (Yoshida et al., 2004). A 2-D velocity structure model was made for our observation area using seismic exploration records across the central Japan (Iidaka et al., 2003). We calculated both travel times by ray tracing method (Fujie et al., 2000; Kubota et al., 2005), and synthetic seismograms by FDM simulation (Larsen and Schultz, 1995). Comparing the observed time series of Hrr and Hzr to the theoretical travel times and synthetic seismograms, we noticed that the wave groups observed at 61-73 km are well corresponding to the theoretical

  2. Time Lapse Gravity and Seismic Monitoring of CO2 Injection at the West Hastings Field, Texas

    NASA Astrophysics Data System (ADS)

    Ferguson, J. F.; Richards, T.; Klopping, F.; MacQueen, J.; Hosseini, S. A.

    2015-12-01

    Time lapse or 4D gravity and seismic reflection surveys are being conducted at the West Hastings Field near Houston, Texas to monitor the progress of CO2 injection. This Department of Energy supported CO2 sequestration experiment is conducted in conjunction with a Denbury Onshore, LLC tertiary recovery project. The reservoir is at a depth of 1.8 km in the Oligocene Frio sands and has been produced since the 1930s. Goals are an accounting and mapping of the injected CO2 and to determine if migration occurs along intra-reservoir faults. An integrated interpretation of the geophysical surveys will be made together with well logs and engineering data. Gravity monitoring of water versus gas replacement has been very successful, but liquid phase CO2 monitoring is problematic due to the smaller density contrast with respect to oil and water. This reservoir has a small volume to depth ratio and hence only a small gravity difference signal is expected on the surface. New borehole gravity technology introduced by Micro-g-Lacoste can make gravity measurements at near reservoir depths with a much higher signal to noise ratio. This method has been successfully evaluated on a simulation of the Hastings project. Field operations have been conducted for repeated surface and borehole gravity surveys beginning in 2013. The surface survey of 95 stations covers an area of 3 by 5 km and 22 borehole gravity logs are run in the interval above the Frio formation. 4D seismic reflection surveys are being made at 6 month intervals on the surface and in 3 VSP wells. CO2 injection into the targeted portion of the reservoir only began in early 2015 and monitoring will continue into 2017. To date only the baseline reservoir conditions have been assessed. The overall success of the gravity monitoring will not be determined until 2017.

  3. Near-field monitoring of seismic source behavior at South African deep gold mines

    NASA Astrophysics Data System (ADS)

    Ogasawara, H.; Nakatani, M.; Iio, Y.; Ishii, H.; Yamada, T.; Naoi, M.; Yasutake, G.; Kawakata, H.; Yamamoto, A.; Yamauchi, T.; Nakao, S.; Yabe, Y.; Otsuki, K.; Satoh, T.; Kato, A.; Shinya, Y.; Nagata, K.; Kuwano, O.; Igarashi, T.; Miyake, H.; Ide, S.; van Aswegen, G.; Mendecki, A.; Ward, T.; SeeSA Research Group

    2007-12-01

    We introduce our SeeSA projects, as important as dense array monitoring According to a mining plan and a geological map detailing locations of faults or weakness, we can anticipate potential M > 2 seismic sources at depths of 2.0 - 3.6 km at South African gold mines. At such potential sources, we have installed instruments prior to an onset of irreversible process to monitor earthquake generation process. From the previous projects for periods of from a year to a few years, the possible widest dynamic range and resolution have revealed the finest detail of the process since 1995 in cooperation with ISS International Ltd and South African gold mines (Mponeng, Bambanani, Tau Tona, Buffelsfontein GM, and ERPM), Wits Univ., Geohydroseis CC., Seismogen CC., OHMS CC., GFZ, GMuG, CSIR. The talk summarizes examples of our successful monitoring and introduces some on-going projects. Highlighted are the following. Yamada et al. [05, 07] demonstrated that mine tremors have rupture process as complex as natural larger earthquakes and the scale dependency of rupture parameters is similar to that for natural larger earthquakes. We successfully recorded strain accumulations larger than 100 micro strain, followed by several hundreds of seismic events (-1 < M < 3; distance < ~ 250 m). The seismicity within about 100m from strainmeters caused frequent, seismic strain-steps; the largest recorded was greater than 100 micro strain by an M2.5 earthquake at a distance within ~100 m. One of the most important results were that no detectable accelerating precursors preceded strain-steps associated with several hundreds of the earthquakes (- 1 < M < 3) catalogued by mine's seismic networks (hereinafter Catalogued E/Q; Takeuchi 05), while significant post-seismic drifts followed some strain-steps by Catalogued E/Qs. Frequently observed were episodic strain changes with durations of much slower than strain-steps associated with the Catalogued E/Qs [Naoi et al. 06]. Striking were some examples

  4. Micro-CT applications to Seismic Monitoring of EOR and Carbon Sequestration Sites

    NASA Astrophysics Data System (ADS)

    Mur, A. J.; Crandall, D.; Purcell, C. C.; Bromhal, G. S.; Soong, Y.; Warzinski, R.; McClendon, B.; Harbert, W.

    2011-12-01

    In order to monitor a CO2 injection site with reflection seismic and VSP surveying, the dynamic rock matrix must be thoroughly understood. We present our results and approach to upscale micro-scale rock matrix properties to reservoir scale and seismic frequency ranges based on theoretical rock wave propagation models and show the richness of useful data produced by micro computed tomography (CT). We have acquired and processed CT images of limestone, sandstone and synthetic samples to gain understanding of 3-D pore orientation, pore volume distribution and pore surface area geometry from 1.25 to 4 micrometer-per-pixel resolution. By comparing CT scans from before and after timed CO2 exposures(Figure 1 shows dissolution along high aspect ratio crack in limestone sample), rock density and pore volume changes relative to time are quantified. In a 19% porosity limestone sample, our analysis identifies and describes over twelve thousand pores in a 26 cubic millimeter volume at a resolution of 3.92 micron/pixel. We produce a digital rock mesh with which we simulate fluid flow in the matrix. As opposed to large scale plume predictions, this small scale flow model helps predict how CO2 will be distributed in a zone that is under a constant flux of CO2. By observing available reactive surface area of the porosity and mass change over a series of time increments, we chemically model limestone-CO2 interactions to predict how, over time, a carbonate reservoir will change due to storage of CO2. This porosity and density change model is applied to a larger-scale reservoir model that detects the presence of CO2 density signatures using AVO (amplitude variation with offset) and VSP (vertical seismic profile) techniques. This application produces theoretical seismic volumes of uncompromised future reservoirs that can be compared to repeat surveys for leak detection.

  5. Seismic monitoring and analysis of deep geothermal projects in St Gallen and Basel, Switzerland

    NASA Astrophysics Data System (ADS)

    Edwards, Benjamin; Kraft, Toni; Cauzzi, Carlo; Kästli, Philipp; Wiemer, Stefan

    2015-05-01

    Monitoring and understanding induced seismicity is critical in order to estimate and mitigate seismic risk related to numerous existing and emerging techniques for natural resource exploitation in the shallow-crust. State of the art approaches for guiding decision making, such as traffic light systems, rely heavily on data such as earthquake location and magnitude that are provided to them. In this context we document the monitoring of a deep geothermal energy project in St Gallen, Switzerland. We focus on the issues of earthquake magnitude, ground motion and macroseismic intensity which are important components of the seismic hazard associated to the project. We highlight the problems with attenuation corrections for magnitude estimation and site amplification that were observed when trying to apply practices used for monitoring regional seismicity to a small-scale monitoring network. Relying on the almost constant source-station distance for events in the geothermal `seismic cloud' we developed a simple procedure, calibrated using several ML > 1.3 events, which allowed the unbiased calculation of ML using only stations of the local monitoring network. The approach determines station specific ML correction terms that account for both the bias of the attenuation correction in the near field and amplification at the site. Since the smallest events (ML < -1) were only observed on a single borehole instrument, a simple relation between the amplitude at the central borehole station of the monitoring network and ML was found. When compared against magnitudes computed over the whole network this single station approach was shown to provide robust estimates (±0.17 units) for the events down to ML = -1. The relation could then be used to estimate the magnitude of even smaller events (ML < -1) only recorded on the central borehole station. Using data from almost 2700 events in Switzerland, we then recalibrated the attenuation correction, extending its range of validity

  6. Monitoring Induced Seismicity with Acoustic-Emission Sensors : The Calibration Problem

    NASA Astrophysics Data System (ADS)

    Plenkers, K.; Kwiatek, G.

    2012-12-01

    We study the effect that an uncalibrated acoustic-emission (AE) sensor has on source parameters using data of the JAGUARS project. The JAGUARS project recorded mining-induced seismicity in Mponeng Gold mine in Carletonville, South Africa in the frequency range 1 kHz < f < 180 kHz combining AE-sensors and accelerometers. Advanced monitoring of induced seismicity in underground structures sometimes includes today the use of high-frequency (f >> 1 kHz) AE monitoring systems. High-frequency monitoring allows the detection of seismic fractures on the centimeter scale and provides therefore important information about the migration of instabilities in the rock. Whereas the temporal-spatial analysis of seismic events recorded with AE sensors provides stable results, the analysis of source parameters including the estimation of magnitudes remains more challenging, because AE sensors are normally not well calibrated and exploit resonance frequencies to allow for high sensitivity. In our study the AE sensors are first calibrated in the frequency range 1kHz to 17 kHz relative to the well calibrated accelerometer. The calibration is possible due to the close employment of both sensor types, which allows to extract the sensor response (including the coupling effect) using signal deconvolution. We estimate three main resonance frequencies at about 2.5 kHz, 6 kHz and 10 kHz. Furthermore we calculate the directivity effect of the AE-sensor that influences the amplitude of the signal by up to - 15 dB. Second, we calculate the effect of the instrument response on the calculation of magnitude, magnitude-frequency distribution and static source parameters. We study magnitudes, magitude-frequency distributions and static source parameters using both the calibrated sensors, as well as the uncalibrated AE sensors. We show the significant uncertainty that is indroduced owing to the AE sensor response and conclude that source parameters often have high uncertainties and are not reliable

  7. Effective CO2 sequestration monitoring using joint inversion result of seismic and electromagnetic data

    NASA Astrophysics Data System (ADS)

    Noh, K.; Jeong, S.; Seol, S. J.; Byun, J.; Kwon, T.

    2015-12-01

    Man-made carbon dioxide (CO2) released into the atmosphere is a significant contributor to the greenhouse gas effect and related global warming. Sequestration of CO2 into saline aquifers has been proposed as one of the most practical options of all geological sequestration possibilities. During CO2 geological sequestration, monitoring is indispensable to delineate the change of CO2 saturation and migration of CO2 in the subsurface. Especially, monitoring of CO2 saturation in aquifers provides useful information for determining amount of injected CO2. Seismic inversion can provide the migration of CO2 plume with high resolution because velocity is reduced when CO2 replaces the pore fluid during CO2 injection. However, the estimation of CO2 saturation using the seismic method is difficult due to the lower sensitivity of the velocity to the saturation when the CO2 saturation up to 20%. On the other hand, marine controlled-source EM (mCSEM) inversion is sensitive to the resistivity changes resulting from variations in CO2 saturation, even though it has poor resolution than seismic method. In this study, we proposed an effective CO2 sequestration monitoring method using joint inversion of seismic and mCSEM data based on a cross-gradient constraint. The method was tested with realistic CO2 injection models in a deep brine aquifer beneath a shallow sea which is selected with consideration for the access convenience for the installation of source and receiver and an environmental safety. Resistivity images of CO2 plume by the proposed method for different CO2 injection stages have been significantly improved over those obtained from individual EM inversion. In addition, we could estimate a reliable CO2 saturation by rock physics model (RPM) using the P-wave velocity and the improved resistivity. The proposed method is a basis of three-dimensional estimation of reservoir parameters such as porosity and fluid saturation, and the method can be also applied for detecting a

  8. A PZT-based smart aggregate for compressive seismic stress monitoring

    NASA Astrophysics Data System (ADS)

    Hou, S.; Zhang, H. B.; Ou, J. P.

    2012-10-01

    A PZT-based smart aggregate (SA) for compressive seismic stress monitoring is proposed in this paper. The proposed SA consists of a piece of PZT (lead zirconate titanate) patch sandwiched between a pair of marble cubes through epoxy. A soft PZT is selected, rendering the SA as a potential actuator in active sensing. Finite element analysis (FEA) was conducted to investigate the stress distribution in the SA under compression, which is used for calculating its sensitivity to compressive stresses. With a commercially available charge amplifier, the frequency response of both the amplitude and the phase shift of the sensing system are investigated by applying the frequency sweep loading scheme on the proposed SA. The frequency ranges from 0.01 to 10 Hz, corresponding to the range of seismic frequency response of most building structures. The alternating load for evaluating SA sensitivity was applied by the servo-hydraulic machine. The lower limit of frequency response is determined to be 0.5 Hz. The depolarization process of the piezoelectric coefficient of the selected PZT material was investigated to decide the load-holding time in calibration tests. The degradation of the piezoelectric coefficient with a series of compressive pre-stresses from 4.8 to 24 MPa was evaluated, and the experimental results showed that the influence from the considered range of pre-stresses is negligible. Using a commercially available charge amplifier, the proposed SA-based sensing system can monitor the seismic stress of low- and middle-rise building structures under moderate earthquakes.

  9. Continuous broadband seismic observation on the Greenland Ice Sheet under Greenland Ice Sheet monitoring Network

    NASA Astrophysics Data System (ADS)

    Tsuboi, Seiji; Kanao, Masaki; Tono, Yoko; Himeno, Tetsuto; Toyokuni, Genti; Childs, Dean; Dahl-Jensen, Trine; anderson, Kent

    2013-04-01

    We have installed the ice sheet broadband seismograph station, called ICE-S (DK.ICESG) in June 2011, in collaboration with IRIS Polar Services under the GreenLand Ice Sheet monitoring Network (GLISN), which is a new, international, broadband seismic capability for Greenland being implemented through the collaboration between Denmark, Canada, France, Germany, Italy, Japan, Norway, Poland, Switzerland, and the USA. The primary purpose of GLISN project is to define the fine structure and detailed mechanisms of glacial earthquakes within the Greenland Ice Sheet. These glacial earthquakes in the magnitude range 4.6-5.1 may be modeled as a large glacial ice mass sliding downhill several meters on its basal surface over duration of 30 to 60 seconds. Glacial earthquakes have been observed at seismic stations within Greenland (Larsen et al, 2006), but the coverage was very sparse and a broadband, real-time seismic network was needed to be installed throughout Greenland's Ice Sheet and perimeter. The National Institute for Polar Research and Japan Agency for Marine-Earth Science and Technology are members of GLISN project and we have started to operate ICESG station since 2011. The station is equipped with a CMG-3T broadband seismometer and a Quanterra Q330 data logger. We have visited the station again in May, 2012 and successfully retrieved one year of continuous records from the broadband seismometer and updated the telemetry system to eventually allow real time monitoring of the station. ICESG station is now daily sending 1 Hz continuous data over the iridium satellite system using RUDICS. The observed three component seismograms demonstrate that the quality of this ice sheet station is good enough to record not only local earthquakes around Greeland but also teleseismic earthquakes. We could record three component broadband seismograms for April 11, 2012 Off the west coast of Northern Sumatra earthquake (Mw8.6). These seismograms show high signal to noise ratio

  10. Complete regional waveform modeling to estimate seismic velocity structure and source parameters for CTBT monitoring

    SciTech Connect

    Bredbeck, T; Rodgers, A; Walter, W

    1999-07-23

    The velocity structures and source parameters estimated by waveform modeling provide valuable information for CTBT monitoring. The inferred crustal and uppermost mantle structures advance understanding of tectonics and guides regionalization for event location and identification efforts. Estimation of source parameters such as seismic moment, depth and mechanism (whether earthquake, explosion or collapse) is crucial to event identification. In this paper we briefly outline some of the waveform modeling research for CTBT monitoring performed in the last year. In the future we will estimate structure for new regions by modeling waveforms of large well-observed events along additional paths. Of particular interest will be the estimation of velocity structure in aseismic regions such as most of Africa and the Former Soviet Union. Our previous work on aseismic regions in the Middle East, north Africa and south Asia give us confidence to proceed with our current methods. Using the inferred velocity models we plan to estimate source parameters for smaller events. It is especially important to obtain seismic moments of earthquakes for use in applying the Magnitude-Distance Amplitude Correction (MDAC; Taylor et al., 1999) to regional body-wave amplitudes for discrimination and calibrating the coda-based magnitude scales.

  11. High frequency seismic monitoring of debris flows at Chalk Cliffs (CO), USA

    NASA Astrophysics Data System (ADS)

    Coviello, Velio; Kean, Jason; Smith, Joel; Coe, Jeffrey; Arattano, Massimo; McCoy, Scott

    2015-04-01

    A growing number of studies adopt passive seismic monitoring techniques to investigate slope instabilities and landslide processes. These techniques are attractive and convenient because large areas can be monitored from a safe distance. This is particularly true when the phenomena under investigation are rapid and infrequent mass movements like debris flows. Different types of devices are used to monitor debris flow processes, but among them ground vibration detectors (GVDs) present several, specific advantages that encourage their use. These advantages include: (i) the possibility to be installed outside the channel bed, (ii) the high adaptability to different and harsh field conditions, and (iii) the capability to detect the debris flow front arrival tens of seconds earlier than contact and stage sensors. Ground vibration data can provide relevant information on the dynamics of debris flows such as timing and velocity of the main surges. However, the processing of the raw seismic signal is usually needed, both to obtain a more effective representation of waveforms and to decrease the amount of data that need to be recorded and analyzed. With this objective, the methods of Amplitude and Impulses are commonly adopted to transform the raw signal to a 1-Hz signal that allows for a more useful representation of the phenomenon. In that way, peaks and other features become more visible and comparable with data obtained from other monitoring devices. In this work, we present the first debris flows seismic recordings gathered in the Chalk Cliffs instrumented basin, central Colorado, USA. In May 2014, two 4.5-Hz, three-axial geophones were installed in the upper part of the catchment. Seismic data are sampled at 333 Hz and then recorded by a standalone recording unit. One geophone is directly installed on bedrock, the other one mounted on a 1-m boulder partially buried in colluvium. This latter sensor integrates a heavily instrumented cross-section consisting of a 225 cm2

  12. MULTIMERMAID: A dedicated multichannel seismic/weather/zoological float for monitoring of the oceans

    NASA Astrophysics Data System (ADS)

    Hello, Y. M.; Bonnieux, S.; Joubert, C.; Sukhovich, A.; Argentino, J.; Yegikyan, M.; Nolet, G.

    2013-12-01

    Delays of seismic P waves are used to make scans or 3D images of the variations in seismic wave speed in the Earth's interior using the techniques of seismic tomography. Observations of such delays are ubiquitous on the continents but rare in oceanic regions, mostly because of the large cost associated with deploying ocean-bottom seismometers. At the same time, several thousand free-drifting profiling floats measure the temperature, salinity and current of the upper 2000 m of the ocean in the Argo program, but are incapable to record and transmit seismic signals. Simons et al. (JGR, 2009) developed the idea to use such floats in order to compensate for the lack of seismic delay observations, especially in the southern hemisphere. We built and tested a prototype of such a seismological sensor using an Apex float from Teledyne Webb Research, a Rafos hydrophone, and electronics developed in collaboration with Osean, a small engineering firm in France. This `MERMAID', for `Mobile Earthquake Recorder in Marine Areas by Independent Divers', has concluded its final design stage and a fleet of 20 units is available for experiments. Since 2012, half of these floats have been deployed in the Mediterranean and in the South Indian Ocean. 10 more will be deployed early in 2014 near the Galapagos islands in the Pacific. Analysis of the first data is allowing us to sharpen the wavelet-based algorithm parameters used to discriminate P-waves from the continuous input signal and adapt it to specific noise conditions. A new multidisciplinary version of Mermaid using a dedicated hydrophone is designed to enlarge the band pass for acoustic signals with much higher frequency than seismic. By combining the same algorithm using wavelet transforms, and by adopting a different monitoring strategy with a dedicated processing, Mermaid is able to continuously analyzes acoustic signals to detect major seismic events, while at the same time regularly checking for weather phenomena such rain

  13. Submarine seismic monitoring of El Hierro volcanic eruption with a 3C-geophone string: applying new acquisition and data processing techniques to volcano monitoring

    NASA Astrophysics Data System (ADS)

    Jurado, Maria Jose; Ripepe, Maurizio; Lopez, Carmen; Blanco, Maria Jose; Crespo, Jose

    2015-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2011 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. Right after the eruption onset, in October 2011 a geophone string was deployed by the CSIC-IGN to monitor seismic activity. Monitoring with the seismic array continued till May 2012. The array was installed less than 2 km away from the new vol¬cano, next to La Restinga village shore in the harbor from 6 to 12m deep into the water. Our purpose was to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. Each geophone consists on a 3-component module based on 3 orthogonal independent sensors that measures ground velocity. Some of the geophones were placed directly on the seabed, some were buried. Due to different factors, as the irregular characteristics of the seafloor. The data was recorded on the surface with a seismometer and stored on a laptop computer. We show how acoustic data collected underwater show a great correlation with the seismic data recorded on land. Finally we compare our data analysis results with the observed sea surface activity (ash and lava emission and degassing). This evidence is disclosing new and innovative tecniques on monitoring submarine volcanic activity. Reference Instituto Geográfico Nacional (IGN), "Serie El Hierro." Internet: http://www.ign.es/ign/resources /volcanologia/HIERRO.html [May, 17. 2013

  14. The SISMA Project: A pre-operative seismic hazard monitoring system.

    NASA Astrophysics Data System (ADS)

    Massimiliano Chersich, M. C.; Amodio, A. A. Angelo; Francia, A. F. Andrea; Sparpaglione, C. S. Claudio

    2009-04-01

    Galileian Plus is currently leading the development, in collaboration with several Italian Universities, of the SISMA (Seismic Information System for Monitoring and Alert) Pilot Project financed by the Italian Space Agency. The system is devoted to the continuous monitoring of the seismic risk and is addressed to support the Italian Civil Protection decisional process. Completion of the Pilot Project is planned at the beginning of 2010. Main scientific paradigm of SISMA is an innovative deterministic approach integrating geophysical models, geodesy and active tectonics. This paper will give a general overview of project along with its progress status and a particular focus will be put on the architectural design details and to the software implementation choices. SISMA is built on top of a software infrastructure developed by Galileian Plus to integrate the scientific programs devoted to the update of seismic risk maps. The main characteristics of the system may be resumed as follow: automatic download of input data; integration of scientific programs; definition and scheduling of chains of processes; monitoring and control of the system through a graphical user interface (GUI); compatibility of the products with ESRI ArcGIS, by mean of post-processing conversion. a) automatic download of input data SISMA needs input data such as GNSS observations, updated seismic catalogue, SAR satellites orbits, etc. that are periodically updated and made available from remote servers through FTP and HTTP. This task is accomplished by a dedicated user configurable component. b) integration of scientific programs SISMA integrates many scientific programs written in different languages (Fortran, C, C++, Perl and Bash) and running into different operating systems. This design requirements lead to the development of a distributed system which is platform independent and is able to run any terminal-based program following few simple predefined rules. c) definition and scheduling of

  15. Broadband seismic monitoring of active volcanoes using deterministic and stochastic approaches

    NASA Astrophysics Data System (ADS)

    Kumagai, H.; Nakano, M.; Maeda, T.; Yepes, H.; Palacios, P.; Ruiz, M. C.; Arrais, S.; Vaca, M.; Molina, I.; Yamashina, T.

    2009-12-01

    of Tungurahua. We determined best-fit source locations at depths of 2.6-2.9 km beneath the summit region, and these sources were consistently explained by volumetric changes caused by bubble growth in magma. The stochastic approach of the source location method and the deterministic approach based on the waveform inversion are both useful to better utilize broadband seismic signals observed at a limited number of stations at active volcanoes, and would contribute to improved seismic volcano monitoring.

  16. Seismic Monitoring at the Decatur, IL, Geologic Carbon Dioxide Sequestration Site

    NASA Astrophysics Data System (ADS)

    Hickman, S. H.; Kaven, J. O.; McGarr, A.; Walter, S. R.; Ellsworth, W. L.; Svitek, J. F.; Burke, L. A.

    2014-12-01

    The viability of carbon capture and storage (CCS) depends on safely sequestering large quantities of carbon dioxide over geologic time scales. One concern is the potential for induced seismicity. We report on seismic monitoring by the U.S. Geological Survey (USGS) at a CCS demonstration site in Decatur, IL. This is the first (and to date only) CCS project in the U.S. to inject large volumes of CO2 into an extensive undisturbed saline reservoir, and thus serves as an important test for future industrial-scale CCS projects. At Decatur, supercritical CO2 is injected at 2.1 km depth into the Mt. Simon Sandstone, which directly overlies granitic basement. The primary sealing cap is the Eau Claire Shale at a depth of about 1.5 km. The Illinois State Geological Survey (ISGS) manages the ongoing Illinois Basin - Decatur Project, a three-year project beginning in November 2011 during which CO2 is injected at an average rate of 1000 metric tons/day. Archer Daniels Midland (ADM) manages the nearby Illinois Industrial Carbon Capture and Storage project, which, pending permit approval, plans to inject 3000 metric tons/day for five years. The USGS seismic network was installed starting in July 2013 and consists of 12 stations, three of which include borehole sensors at depths of 150 m. The aperture of this network is roughly 8 km, centered on the injection well. A one-dimensional velocity model was derived from a vertical seismic profile survey acquired by ADM and the ISGS to a depth of 2.2 km, tied into acoustic logs from a deep observation well and the USGS borehole stations. This model was used together with absolute and double-difference techniques to locate seismic events. These events group into two clusters: 0.4 to 1.0 km NE and 1.8 to 2.6 km WNW from the injection well, with moment magnitudes ranging from -0.8 to 1.1. Most of these events are in the granitic basement, well below the cap rock, and are unlikely to have compromised the integrity of the seal.

  17. Induced Seismicity Monitoring of an Underground Salt Cavern Prone to Collapse

    NASA Astrophysics Data System (ADS)

    Mercerat, E. D.; Driad-Lebeau, L.; Bernard, P.

    2010-02-01

    Within the framework of a large research project launched to assess the feasibility of microseismic monitoring of growing underground caverns, this specific work focuses on the analysis of the induced seismicity recorded in a salt mine environment. A local seismic network has been installed over an underground salt cavern located in the Lorraine basin (Northeast of France). The microseismic network includes four 3-components and three single component geophones deployed at depths between 30 and 125 m in cemented boreholes drilled in the vicinity of the study area. The underground cavern under monitoring is located within a salt layer at 180 m depth and it presents a rather irregular shape that can be approximated by a cylindrical volume of 50 m height and 180 m diameter. Presently, the cavern is full of saturated brine inducing a significant pressure on its walls (~2.0 MPa) to keep the overburden mechanically stable. Nevertheless some small microseismic events were recorded by the network and analyzed (approximately 2,000 events in 2 years of recording). In October 2005 and April 2007, two controlled pressure transient experiments were carried out in the cavern, in order to analyze the mechanical response of the overburden by tracking the induced microseismicity. The recorded events were mainly grouped in clusters of 3-30 s of signal duration with emergent first arrivals and rather low frequency content (between 20 and 120 Hz). Some of these events have been spatially located by travel-time picking close to the actual cavern and its immediate roof. Preliminary spectral analysis of isolated microearthquakes suggests sources with non-negligible tensile components possibly related to fluid-filled cracks. Rock-debris falling into the cavern from delamination of clay marls in the immediate roof is probably another source of seismic excitation. This was later confirmed when the most important seismic swarms occurred at the site during May 2007, accompanied by the

  18. Elevated Seismic Activity Beneath the Slumbering Morne aux Diables Volcano, Northern Dominica and the Monitoring Role of the Seismic Research Centre

    NASA Astrophysics Data System (ADS)

    Watts, R. B.; Robertson, R. E.; Abraham, W.; Cole, P.; de Roche, T.; Edwards, S.; Higgins, M.; Johnson, M.; Joseph, E. P.; Latchman, J.; Lynch, L.; Nath, N.; Ramsingh, C.; Stewart, R. C.

    2012-12-01

    Since June 2009, periods of elevated seismic activity have been experienced around the flanks of Morne Aux Diables Volcano in northern Dominica. This long-dormant volcano is a complex of 7 andesitic lava domes with a central depression where a cold soufrière is evident. Prior to this activity, seismicity was very quiet except for a short period in 2000 and an intense short-lived swarm in April 2003. The most recent earthquake activity has been regularly felt by residents in villages on all flanks of the complex. In Dec 09/Jan10, scientists from the Seismic Research Centre (SRC), based in Trinidad & Tobago, in collaboration with staff of the Office of Disaster Management (ODM) and Dominica Public Seismic Network (DPSN) improved the monitoring capacity around this volcano from 1 to 7 seismic stations. Earthquakes are determined to be volcano-tectonic in nature and located at shallow depths (<4 km) beneath the central depression. Additionally, in Jan/Feb 10 geothermal sampling was undertaken and 2 permanent GPS sites were deployed. Public information leaflets prepared by SRC scientists using a "Question & Answer" format have been distributed to concerned citizens whilst many public meetings were carried out by ODM staff. Field investigations indicate that the previous Late Pleistocene activity of Morne Aux Diables switched from Pelèan dome growth and gravitational collapse to more explosive pumice-falls and associated ignimbrites, both styles forming extensive pyroclastic fans around the central complex. The town of Portsmouth is located on one of these fans ~5 km southwest of the central depression. Sporadic, short bursts of seismic activity continue at the time of writing.

  19. Understanding the dynamics of a geyser from temporal monitoring of seismic source

    NASA Astrophysics Data System (ADS)

    Cros, E. C.; Roux, P.; Vandemeulebrouck, J.; Kedar, S.

    2010-12-01

    Old Faithful Geyser is the most popular geyser in Yellowstone National Park. The predictability, the repeatability and the short time lag, ~1 hour, between two eruptions make its study very convenient to apprehend its cycle and to make progress in the understanding of geyser's dynamics. The geyser's edifice is characterized by a diameter of 60 m, a height of 4m, with an opening of approximately 2 m x 1 m, a crack-like aperture. In 1992, Sharon Kedar deployed 96 geophones around the geyser vent in order to continuously record seismic signals during several eruptive cycles. The signal recorded at Old Faithful is characterized by small impulsive events, with durations of ~1s, related to bubble collapse in the boiling water column. We revisited the seismic signals recorded by Sharon Kedar in order to determine the locations of the source of these events during an entire cycle with the objective to monitor the temporal evolution of the system. An analysis of 2 hours of seismic data was performed using Matched Field Processing (MFP) techniques, in order to localize the source of the signal produced by the geyser's activity. The seismic signal recorded on the stations is strongly coherent from a station to another which is a prerequisite to MFP. This method is based on the comparison of the phase delays of real data with the phase delays of synthetic signals (i.e. replica). The synthetic signals correspond to the acoustic field recorded at the geophone locations for a certain position of the candidate source at every node of a search grid. When the correlation of the data with the synthetic signals is maximum, the candidate point source and the true point source are co-located. The MFP can be linear (i.e. Bartlett) or non linear (i.e. Minimum Variance Distorsionless Response). The MFP processor is generally incoherently averaged over the frequency bandwidth of interest but the cross-correlation of the data with a reference station permits to average coherently the signal

  20. Synthetic seismic monitoring using reverse-time migration and Kirchhoff migration for CO2 sequestration in Korea

    NASA Astrophysics Data System (ADS)

    Kim, W.; Kim, Y.; Min, D.; Oh, J.; Huh, C.; Kang, S.

    2012-12-01

    During last two decades, CO2 sequestration in the subsurface has been extensively studied and progressed as a direct tool to reduce CO2 emission. Commercial projects such as Sleipner, In Salah and Weyburn that inject more than one million tons of CO2 per year are operated actively as well as test projects such as Ketzin to study the behavior of CO2 and the monitoring techniques. Korea also began the CCS (CO2 capture and storage) project. One of the prospects for CO2 sequestration in Korea is the southwestern continental margin of Ulleung basin. To monitor the behavior of CO2 underground for the evaluation of stability and safety, several geophysical monitoring techniques should be applied. Among various geophysical monitoring techniques, seismic survey is considered as the most effective tool. To verify CO2 migration in the subsurface more effectively, seismic numerical simulation is an essential process. Furthermore, the efficiency of the seismic migration techniques should be investigated for various cases because numerical seismic simulation and migration test help us accurately interpret CO2 migration. In this study, we apply the reverse-time migration and Kirchhoff migration to synthetic seismic monitoring data generated for the simplified model based on the geological structures of Ulleung basin in Korea. Synthetic seismic monitoring data are generated for various cases of CO2 migration in the subsurface. From the seismic migration images, we can investigate CO2 diffusion patterns indirectly. From seismic monitoring simulation, it is noted that while the reverse-time migration generates clear subsurface images when subsurface structures are steeply dipping, Kirchhoff migration has an advantage in imaging horizontal-layered structures such as depositional sediments appearing in the continental shelf. The reverse-time migration and Kirchhoff migration present reliable subsurface images for the potential site characterized by stratigraphical traps. In case of

  1. Seismic Monitoring at the Underground Nuclear Research Laboratory in Mol, Belgium - 12461

    SciTech Connect

    Areias, Lou

    2012-07-01

    Micro-seismic piezoelectric transmitters installed in the Boom Clay at HADES produce predominantly high frequency signals, above 5 kHz, which favour the generation of P waves. However, above 5 kHz shear (S) waves are not detected by the installation. Recent studies at HADES indicate that it is possible to detect S waves with the current setup when applying a low (5 kHz) cut-off filter. The results also show that S waves have frequencies mainly below 1 kHz, while P waves are detectable at all of the eight transmitted frequencies but show optimum resolution in the range of 7 to 23 kHz. Although the system offers great potential for monitoring the evolution of a geological disposal site, further improvements in signal generation and treatment are necessary. One of these includes the design and testing of a new S-wave source at HADES planned in the framework of the EC MoDeRn project (http://www.modern-fp7.eu/). The seismic installation at HADES continues to provide useful information on the changing properties of the Boom Clay in the near and far field around the PRACLAY gallery since its start of operation in 2006. In the future, the system will also monitor the PRACLAY heater experiment that will start in 2012 and go on for 10 years. So far, the results of long term seismic monitoring show that S waves contain frequencies mainly below 1 kHz. The P waves are detectable at all of the eight transmitted frequencies but show optimum resolution in the range of 7 to 23 kHz. To improve the signal-to-noise ratio and detection of S waves at HADES it is, therefore, necessary to apply a strong low-pass filter that matches the S-wave frequency content. Due to the different frequency ranges observed for the P and S waves, it is recommended to treat them separately. The evolution of both P and S wave velocities in the EDZ around the PRACLAY gallery show continued recovery since its construction in 2007. Modelling results of the variation in crack density obtained from the inversion

  2. Initial results from seismic monitoring at the Aquistore CO2 storage site, Saskatchewan, Canada

    SciTech Connect

    White, D. J.; Roach, L. A.N.; Roberts, B.; Daley, T. M.

    2014-12-31

    The Aquistore Project, located near Estevan, Saskatchewan, is one of the first integrated commercial-scale CO2 storage projects in the world that is designed to demonstrate CO2 storage in a deep saline aquifer. Starting in 2014, CO2 captured from the nearby Boundary Dam coal-fired power plant will be transported via pipeline to the storage site and to nearby oil fields for enhanced oil recovery. At the Aquistore site, the CO2 will be injected into a brine-filled sandstone formation at ~3200 m depth using the deepest well in Saskatchewan. The suitability of the geological formations that will host the injected CO2 has been predetermined through 3D characterization using high-resolution 3D seismic images and deep well information. These data show that 1) there are no significant faults in the immediate area of the storage site, 2) the regional sealing formation is continuous in the area, and 3) the reservoir is not adversely affected by knolls on the surface of the underlying Precambrian basement. Furthermore, the Aquistore site is located within an intracratonic region characterized by extremely low levels of seismicity. This is in spite of oil-field related water injection in the nearby Weyburn-Midale field where a total of 656 million m3 of water have been injected since the 1960`s with no demonstrable related induced seismicity. A key element of the Aquistore research program is the further development of methods to monitor the security and subsurface distribution of the injected CO2. Toward this end, a permanent areal seismic monitoring array was deployed in 2012, comprising 630 vertical-component geophones installed at 20 m depth on a 2.5x2.5 km regular grid. This permanent array is designed to provide improved 3D time-lapse seismic imaging for monitoring subsurface CO2. Prior to the onset of CO2 injection, calibration 3D surveys were acquired in May and November

  3. Fully Autonomous Multiplet Event Detection: Application to Local-Distance Monitoring of Blood Falls Seismicity

    SciTech Connect

    Carmichael, Joshua Daniel; Carr, Christina; Pettit, Erin C.

    2015-06-18

    We apply a fully autonomous icequake detection methodology to a single day of high-sample rate (200 Hz) seismic network data recorded from the terminus of Taylor Glacier, ANT that temporally coincided with a brine release episode near Blood Falls (May 13, 2014). We demonstrate a statistically validated procedure to assemble waveforms triggered by icequakes into populations of clusters linked by intra-event waveform similarity. Our processing methodology implements a noise-adaptive power detector coupled with a complete-linkage clustering algorithm and noise-adaptive correlation detector. This detector-chain reveals a population of 20 multiplet sequences that includes ~150 icequakes and produces zero false alarms on the concurrent, diurnally variable noise. Our results are very promising for identifying changes in background seismicity associated with the presence or absence of brine release episodes. We thereby suggest that our methodology could be applied to longer time periods to establish a brine-release monitoring program for Blood Falls that is based on icequake detections.

  4. Strain Observation Affected by Groundwater-Level Change in Seismic Precursor Monitoring

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Cao, Daiyong; Zhang, Jingfa

    2016-09-01

    Groundwater extraction is one of the most typical disturbance factors for strain observation in seismic precursor monitoring. The statistic regression method is used to study based on the relation between the variation of strain and the groundwater level. The least square regression linear model is built between the annual variation of Sangzi groundwater level and the Xiaoxinzhuang strain data. Such model meets t test with significance level α = 0. 0 5 , which confirms that groundwater-level change in each year affects strain measurement significantly and strain's trend variation is related to groundwater-level change. Consequently, a new correction method about strain data is put forward based on the groundwater-level annual variation to eliminate the trend change. Results indicate that the accumulated residual deformation causes the horizontal displacement and strain change, which is on account of that the amount of groundwater recharge is less than that of extraction around Xiaoxinzhuang cave, the phreatic surface continues to descend, and residual deformation accumulates and leads to local subsidence area. Therefore, the decline trend change of strain is related to groundwater-level change and is not seismic precursor.

  5. Monitoring Hurricanes with a Dense Seismic Array: Joint Inversion of Seismic and Barometric Data for Surface-Pressure Source

    NASA Astrophysics Data System (ADS)

    Valentine, A. P.; Al-Attar, D.; Trampert, J.; Woodhouse, J. H.

    2014-12-01

    Tropical cyclones (hurricanes and typhoons) are mostly atmospheric phenomena but they also generate significant ground motions in the solid earth when they become strong. If a dense seismological array exists along the path of a hurricane, we can learn about some processes near the hurricane eye through seismic data. In this study, we report our analysis of Hurricane Arthur which passed near Earthscope's Transportable Array (TA), a network of seismometers located at the time along the east coast of the US. Hurricane Arthur mostly traveled along the eastern coast of the US from July 1 to July 5, 2014; however, it made landfall for a short time on the coast of North Carolina at 0315 UTC on July 4. The next few hours provided us with a short span of seismic and barometric data associated with the center of Hurricane Arthur. Our basic approach to analyze this data is the same as in a previous study we conducted of Hurricane Isaac (2012), where we analyzed the seismic amplitude-distance data and the pressure amplitude-distance data for each 6-hour location of the hurricane. Here, we performed a joint inversion of the seismic and barometric data while Hurricane Arthur was nearest the coast. Barometer data provides the information on pressure source, which is the source of seismic-wave excitation and seismic data provides the resultant wavefields. We confine our analysis to frequencies below 0.02 Hz because in higher frequency bands ocean waves created the dominant seismic waves. In a similar manner to our previous study on Hurricane Isaac, we invert for the pressure correlation length. The results were consistent with what was seen for Hurricane Isaac in that we observed a signal generated by Hurricane Arthur's eyewall. After landfall, there is a peak at about 70-80km from the center of the hurricane in both the seismic and the barometric data. We also found that the correlation length changes with distance from the hurricane center and also has a peak around 70-80km.

  6. Hydra—The National Earthquake Information Center’s 24/7 seismic monitoring, analysis, catalog production, quality analysis, and special studies tool suite

    USGS Publications Warehouse

    Patton, John M.; Guy, Michelle R.; Benz, Harley M.; Buland, Raymond P.; Erickson, Brian K.; Kragness, David S.

    2016-08-18

    This report provides an overview of the capabilities and design of Hydra, the global seismic monitoring and analysis system used for earthquake response and catalog production at the U.S. Geological Survey National Earthquake Information Center (NEIC). Hydra supports the NEIC’s worldwide earthquake monitoring mission in areas such as seismic event detection, seismic data insertion and storage, seismic data processing and analysis, and seismic data output.The Hydra system automatically identifies seismic phase arrival times and detects the occurrence of earthquakes in near-real time. The system integrates and inserts parametric and waveform seismic data into discrete events in a database for analysis. Hydra computes seismic event parameters, including locations, multiple magnitudes, moment tensors, and depth estimates. Hydra supports the NEIC’s 24/7 analyst staff with a suite of seismic analysis graphical user interfaces.In addition to the NEIC’s monitoring needs, the system supports the processing of aftershock and temporary deployment data, and supports the NEIC’s quality assurance procedures. The Hydra system continues to be developed to expand its seismic analysis and monitoring capabilities.

  7. INL Seismic Monitoring Annual Report: January 1, 2007 - December 31, 2007

    SciTech Connect

    S. J. Payne; N. S. Carpenter; J. M. Hodges; R. G. Berg

    2008-09-01

    During 2007, the INL Seismic Monitoring Program evaluated 2,515 earthquakes from around the world, the western United States, and local region of the eastern Snake River Plain. 671 earthquakes and man-made blasts occurred within the local region outside and within a 161-km (or 100-mile) radius of INL. Of these events, eleven were small to moderate size earthquakes ranging in magnitude from 3.0 to 4.8. 341 earthquakes occurred within the 161-km radius of INL and the majority of these earthquakes were located in active regions of the Basin and Range Province that surrounds the ESRP. Three earthquakes were located within the ESRP at Craters of the Moon National Monument. The earthquakes were of Mc 0.9, 1.4, and 1.8. Since 1972, INL has recorded 36 small-magnitude microearthquakes (M < 2.0) within the ESRP.

  8. Analysis of seismic sources for different mechanisms of fracture growth for microseismic monitoring applications

    NASA Astrophysics Data System (ADS)

    Duchkov, A. A.; Stefanov, Yu. P.

    2015-10-01

    We have developed and illustrated an approach for geomechanic modeling of elastic wave generation (microsiesmic event occurrence) during incremental fracture growth. We then derived properties of effective point seismic sources (radiation patterns) approximating obtained wavefields. These results establish connection between geomechanic models of hydraulic fracturing and microseismic monitoring. Thus, the results of the moment tensor inversion of microseismic data can be related to different geomechanic scenarios of hydraulic fracture growth. In future, the results can be used for calibrating hydrofrac models. We carried out a series of numerical simulations and made some observations about wave generation during fracture growth. In particular when the growing fracture hits pre-existing crack then it generates much stronger microseismic event compared to fracture growth in homogeneous medium (radiation pattern is very close to the theoretical dipole-type source mechanism).

  9. Analysis of seismic sources for different mechanisms of fracture growth for microseismic monitoring applications

    SciTech Connect

    Duchkov, A. A.; Stefanov, Yu. P.

    2015-10-27

    We have developed and illustrated an approach for geomechanic modeling of elastic wave generation (microsiesmic event occurrence) during incremental fracture growth. We then derived properties of effective point seismic sources (radiation patterns) approximating obtained wavefields. These results establish connection between geomechanic models of hydraulic fracturing and microseismic monitoring. Thus, the results of the moment tensor inversion of microseismic data can be related to different geomechanic scenarios of hydraulic fracture growth. In future, the results can be used for calibrating hydrofrac models. We carried out a series of numerical simulations and made some observations about wave generation during fracture growth. In particular when the growing fracture hits pre-existing crack then it generates much stronger microseismic event compared to fracture growth in homogeneous medium (radiation pattern is very close to the theoretical dipole-type source mechanism)

  10. Searchlight Correlation Detectors: Optimal Seismic Monitoring Using Regional and Global Networks

    NASA Astrophysics Data System (ADS)

    Gibbons, Steven J.; Kværna, Tormod; Näsholm, Sven Peter

    2015-04-01

    The sensitivity of correlation detectors increases greatly when the outputs from multiple seismic traces are considered. For single-array monitoring, a zero-offset stack of individual correlation traces will provide significant noise suppression and enhanced sensitivity for a source region surrounding the hypocenter of the master event. The extent of this region is limited only by the decrease in waveform similarity with increasing hypocenter separation. When a regional or global network of arrays and/or 3-component stations is employed, the zero-offset approach is only optimal when the master and detected events are co-located exactly. In many monitoring situations, including nuclear test sites and geothermal fields, events may be separated by up to many hundreds of meters while still retaining sufficient waveform similarity for correlation detection on single channels. However, the traveltime differences resulting from the hypocenter separation may result in significant beam loss on the zero-offset stack and a deployment of many beams for different hypothetical source locations in geographical space is required. The beam deployment necessary for optimal performance of the correlation detectors is determined by an empirical network response function which is most easily evaluated using the auto-correlation functions of the waveform templates from the master event. The correlation detector beam deployments for providing optimal network sensitivity for the North Korea nuclear test site are demonstrated for both regional and teleseismic monitoring configurations.

  11. Improved Temporal Resolution of Ambient Seismic Noise Monitoring without the Green's Function

    NASA Astrophysics Data System (ADS)

    Hadziioannou, Céline; Larose, Eric; Baig, Adam; Campillo, Michel

    2010-05-01

    Ambient noise crosscorrelations have been used on several occasions to monitor temporal variations in seismic velocity. In particular, Brenguier et al. (Science, 2008) find coseismic and postseismic velocity changes around a fault zone in Parkfield, California. In this study, and in others, it was initially assumed that a correct reconstruction of the Green's function is as necessary for temporal monitoring as it is for imaging. We show through laboratory experiments that a stable waveform reconstruction is sufficient to retrieve relative temporal variations. Armed with this knowledge, we revisit the data from Parkfield. One way to obtain a stable waveform, with an acceptable signal to noise ratio, is to average the correlations over a long period of time. However, for the application to monitoring one wants the possibility of following short-term variations. How can we resolve this conflict and improve temporal resolution without sacrificing SNR? We show that by applying an adaptive filter (Baig et al, J. Geophys. Res., 2009) to the Parkfield dataset the temporal resolution can be increased from 30 days up to 1 day. With this, we show that the velocity drop observed is coseismic with the Parkfield earthquake.

  12. Recorded earthquake responses from the integrated seismic monitoring network of the Atwood Building, Anchorage, Alaska

    USGS Publications Warehouse

    Celebi, M.

    2006-01-01

    An integrated seismic monitoring system with a total of 53 channels of accelerometers is now operating in and at the nearby free-field site of the 20-story steel-framed Atwood Building in highly seismic Anchorage, Alaska. The building has a single-story basement and a reinforced concrete foundation without piles. The monitoring system comprises a 32-channel structural array and a 21-channel site array. Accelerometers are deployed on 10 levels of the building to assess translational, torsional, and rocking motions, interstory drift (displacement) between selected pairs of adjacent floors, and average drift between floors. The site array, located approximately a city block from the building, comprises seven triaxial accelerometers, one at the surface and six in boreholes ranging in depths from 15 to 200 feet (???5-60 meters). The arrays have already recorded low-amplitude shaking responses of the building and the site caused by numerous earthquakes at distances ranging from tens to a couple of hundred kilometers. Data from an earthquake that occurred 186 km away traces the propagation of waves from the deepest borehole to the roof of the building in approximately 0.5 seconds. Fundamental structural frequencies [0.58 Hz (NS) and 0.47 Hz (EW)], low damping percentages (2-4%), mode coupling, and beating effects are identified. The fundamental site frequency at approximately 1.5 Hz is close to the second modal frequencies (1.83 Hz NS and 1.43 EW) of the building, which may cause resonance of the building. Additional earthquakes prove repeatability of these characteristics; however, stronger shaking may alter these conclusions. ?? 2006, Earthquake Engineering Research Institute.

  13. Real-time monitoring of pre-collapse phenomena using locations of seismic sources

    NASA Astrophysics Data System (ADS)

    Jarpe, S. P.; Burkhard, N. R.

    1985-09-01

    We attempted to develop a method for real-time monitoring of pre-collapse activity in the cavity region using seismic trace data recorded following EGMONT. Signals from an array of eight three-component, short-period seismometer stations were recorded using a new high dynamic range, portable digital telemetry and recording system. Three stations were located at 1 DOB, three at 2 DOB, and two at 4 DOB. Seismic data were recorded continuously before, during, and after collapse. As has been reported by previous studies, the pre-collapse period was characterized by a continuous high level of activity, but unlike previous studies, the recording system was not saturated, which allowed us to attempt to process the information. We discovered that all of the signals at a given location are very similar, but that the character is very different at the separate locations. A variety of computer processing techniques were attempted with the aim of obtaining source locations accurately enough to monitor chimney growth, i.e., +-50m both horizontally and vertically. These included the traditional methods of picking arrival times of phases at the different stations and using the time differences to locate the source, as well as more unusual approaches. We concluded that an array of sensors such as that used for EGMONT will not produce satisfactory results with real-time processing. We did, however, come up with an approach using several small, closely-spaced groups of sensors called arrays that should be more successful for this type of situation. The arrays, if designed properly, will take advantage of the similarity of the signals at a given location to estimate source direction. The directions from several arrays to one source can be combined to determine the source location.

  14. Monitoring deep geodynamic processes within Vrancea intermediate-depth seismic zone by geodetic means

    NASA Astrophysics Data System (ADS)

    Besutiu, Lucian; Zlagnean, Luminita

    2015-04-01

    Background Located in the bending zone of East Carpathians, the so-called Vrancea zone is one of the most active seismic regions in Europe. Despite many years of international research, its intermediate-depth seismicity within full intra-continental environment still represents a challenge of the 21st century. Infrastructure In the attempt to join the above-mentioned efforts, the Solid Earth Dynamics Department (SEDD) in the Institute of Geodynamics of the Romanian Academy has developed a special research infrastructure, mainly devoted to gravity and space geodesy observations. A geodetic network covering the epicentre area of the intermediate-depth earthquakes has been designed and implemented for monitoring deep geodynamic processes and their surface echoes. Within each base-station of the above-mentioned network, a still-reinforced concrete pillar allows for high accuracy repeated gravity and GPS determinations. Results Starting from some results of the previously run CERGOP and UNIGRACE European programmes, to which additional SEDD repeated field campaigns were added, an unusual geodynamic behaviour has been revealed in the area. 1) Crust deformation: unlike the overall uprising of East Carpathians, as a result of denudation followed by erosion, their SE bending zone, with Vrancea epicentre area exhibits a slight subsidence. 2) Gravity change: more than 200 microgals non-tidal gravity decrease over a 20 years time-span has been noticed within the subsiding area. Extended observations showed the gravity lowering as a nowadays continuing process. Interpretation This strange combination of topography subsidence and gravity lowering has been interpreted in terms of crust stretching in the Vrancea epicentre zone due to the gravity pull created by densification of the lower crust as a result of phase-transform processes taking place in the lithospheric compartment sunken into the upper mantle. The occurrence of crust earthquakes with vertical-extension focal

  15. Bedload Hysteresis and Bedform Deformation Rates Investigated with Physical Samples, Multibeam Sonar, and Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Gaeuman, D.; Schmandt, B.; Stewart, R. L.; Pryor, C.

    2015-12-01

    Field and laboratory observations indicate that bedload transport frequently exhibits clockwise hysteresis. Several grain-scale mechanisms could account for this, including increases in the median surface particle size, development of stable particle arrangements on the bed surface, or reductions in the sediment supply. Alternatively, bedload hysteresis at steady flow could occur if the bed configuration stabilizes as bedforms approach a configuration that is in quasi-equilibrium with prevailing hydraulic conditions. The roles of bedform development and changes in coarse sediment availability as potential causes of hysteresis are investigated with a unique dataset obtained during a high flow release in the Trinity River, a regulated gravel-bed river in California. Physical bedload samples were obtained over the release hydrograph along with continuous seismic monitoring with 3-component broadband seismometers at four locations along the river. At one location, changes in bed topography during the peak of the release were monitored with repeated multibeam sonar surveys over a channel length of about 1 km. In addition, a network of 80 vertical-component seismometers was deployed adjacent to the channel to support development of a time series of maps showing local variations in seismic energy production on the stream bed. Finally, a gravel augmentation operation was being implemented at the upstream end of the reach during the release peak, permitting evaluation of how changes in sediment supply affect downstream transport rates. Sampled bedload transport rates were found to increase briefly during gravel augmentation operations, but return to pre-augmentation levels within a few hours after augmentation activities stop and generally decline over a period of peak flow lasting about 3 days. The sonar data indicate that most of the topographic change observed during the peak flow period occurred in the first several hours of the period, supporting the hypothesis that

  16. Long- and Short-Term Magmatic Behavior of Piton De La Fournaise Volcano Inferred from Noise-Based Seismic Monitoring

    NASA Astrophysics Data System (ADS)

    Brenguier, F.; Rivet, D. N.; Kowalski, P.; Larose, E. F.; Lecocq, T.; Chaput, J. A.; Rambaud, S.; Shapiro, N.; Campillo, M.; Roux, P.; Ferrazzini, V.; Villeneuve, N.

    2014-12-01

    Probing the long-term preparation of eruptions as well as the short-term initiation and transport of magma to surface remains extremely difficult. One reason is that it is hardly possible to directly monitor at depth the magma storage area. One way to overcome this issue is to use seismic waves that, through their propagation, sample the targets of interest. Here we use ambient seismic waves to infer temporal mechanical property changes of Piton de la Fournaise volcano (PdF, La Réunion island). We find both 1) a long-term behavior that might reflect processes of deep magma replenishment as well as 2) short-term variations that are controlled by both environmental (rainfall) and pre-eruptive perturbations that are or not associated with edifice deformation. We will discuss the possible origins for such pre-eruptive perturbations (effects of magma pressure buildup or fluid pore pressure increase by heat transfer). In order to improve the depth resolution of our observations we deployed 3 seismic arrays for a total of 300 seismometers on PdF volcano in the framework of VolcArray project. We will present first results discussing how dense seismic arrays can be useful for noise-based seismic imaging and monitoring.

  17. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    SciTech Connect

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2007-06-30

    The objective of this research project was to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in the hopes of observing changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE No.DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data. Attribute analysis was a very useful tool in enhancing changes in seismic character present, but difficult to interpret on time amplitude slices. Lessons learned from and tools/techniques developed during this project will allow high-resolution seismic imaging to be routinely applied to many CO{sub 2} injection programs in a large percentage of shallow carbonate oil fields in the midcontinent.

  18. Can riverside seismic monitoring constrain temporal and spatial variations in bedload transport during a controlled flood of the Trinity River?

    NASA Astrophysics Data System (ADS)

    Glasgow, M. E.; Schmandt, B.; Gaeuman, D.

    2015-12-01

    To evaluate the utility of riverside seismic monitoring for constraining temporal and spatial variations in coarse bedload transport in gravel-bed rivers we collected seismic data during a dam-controlled flood of the Trinity River in northern California in May 2015. This field area was chosen because the Trinity River Restoration Project conducts extensive monitoring of water and sediment transport, and riverbed morphology to guide management of the river with the goal of improving salmon habitat. Four three component broadband seismometers were collocated with water discharge and bedload physical sampling sites along a ~30 km reach of the Trinity River downstream of the Lewiston Dam. Arrays with 10-80 cable-free vertical component geophones were also deployed at each of the four sites in order to constrain spatial variability and amplitude decay of seismic signals emanating from the river. Nominal inter-station spacing within the geophone arrays was ~30 m. The largest geophone array consisted of 83 nodes along a 700 m reach of the Trinity River with a gravel augmentation site at its upstream end. Initial analyses of the seismic data show that ground velocity power from averaged from ~7 - 90 Hz is correlated with discharge at all sites. The array at the gravel injection site shows greater high frequency (>30 Hz) power at the upstream end where gravel was injected during the release compared to ~300 m downstream, consistent with bedload transport providing a significant source of seismic energy in addition to water discharge. Declining seismic power during a ~3 day plateau at peak discharge when physical sampler data shows decreasing bedload flux provides a further indication that the seismic data are sensitive to bedload transport. We will use the array data to back-project the seismic signals in multiple frequency bands into the channel to create maps of the time-varying spatial intensity of seismic energy production. We hypothesize that the greatest seismic

  19. The CSMS (Configurable Seismic Monitoring System) Poorboy deployment: Seismic recording in Pinedale, Wyoming, of the Bullion NTS (Nevada Test Site) nuclear test under the verification provisions of the new TTBT protocol

    SciTech Connect

    Harben, P.E.; Rock, D.W.; Carlson, R.C.

    1990-07-10

    The Configurable Seismic Monitoring System (CSMS), developed at the Lawrence Livermore National Laboratory (LLNL) was deployed in a 13-m deep vault on the AFTAC facility at Pinedale, Wyoming to record the Bullion nuclear test. The purpose of the exercise was to meet all provisions of the new TTBT protocol on in-country seismic recording at a Designated Seismic Station (DSS). The CSMS successfully recorded the Bullion event consistent with and meeting all requirements in the new treaty protocol. In addition, desirable seismic system features not specified in the treaty protocol were determined; treaty protocol ambiguities were identified, and useful background noise recordings at the Pinedale site were obtained. 10 figs.

  20. Frequency-dependent processing and interpretation (FDPI) of seismic data for identifying, imaging and monitoring fluid-saturated underground reservoirs

    DOEpatents

    Goloshubin, Gennady M.; Korneev, Valeri A.

    2005-09-06

    A method for identifying, imaging and monitoring dry or fluid-saturated underground reservoirs using seismic waves reflected from target porous or fractured layers is set forth. Seismic imaging the porous or fractured layer occurs by low pass filtering of the windowed reflections from the target porous or fractured layers leaving frequencies below low-most corner (or full width at half maximum) of a recorded frequency spectra. Additionally, the ratio of image amplitudes is shown to be approximately proportional to reservoir permeability, viscosity of fluid, and the fluid saturation of the porous or fractured layers.

  1. Active and passive seismic methods for characterization and monitoring of unstable rock masses: field surveys, laboratory tests and modeling.

    NASA Astrophysics Data System (ADS)

    Colombero, Chiara; Baillet, Laurent; Comina, Cesare; Jongmans, Denis; Vinciguerra, Sergio

    2016-04-01

    Appropriate characterization and monitoring of potentially unstable rock masses may provide a better knowledge of the active processes and help to forecast the evolution to failure. Among the available geophysical methods, active seismic surveys are often suitable to infer the internal structure and the fracturing conditions of the unstable body. For monitoring purposes, although remote-sensing techniques and in-situ geotechnical measurements are successfully tested on landslides, they may not be suitable to early forecast sudden rapid rockslides. Passive seismic monitoring can help for this purpose. Detection, classification and localization of microseismic events within the prone-to-fall rock mass can provide information about the incipient failure of internal rock bridges. Acceleration to failure can be detected from an increasing microseismic event rate. The latter can be compared with meteorological data to understand the external factors controlling stability. On the other hand, seismic noise recorded on prone-to-fall rock slopes shows that the temporal variations in spectral content and correlation of ambient vibrations can be related to both reversible and irreversible changes within the rock mass. We present the results of the active and passive seismic data acquired at the potentially unstable granitic cliff of Madonna del Sasso (NW Italy). Down-hole tests, surface refraction and cross-hole tomography were carried out for the characterization of the fracturing state of the site. Field surveys were implemented with laboratory determination of physico-mechanical properties on rock samples and measurements of the ultrasonic pulse velocity. This multi-scale approach led to a lithological interpretation of the seismic velocity field obtained at the site and to a systematic correlation of the measured velocities with physical properties (density and porosity) and macroscopic features of the granitic cliff (fracturing, weathering and anisotropy). Continuous

  2. Frequency-dependent processing and interpretation (FDPI) of seismic data for identifying, imaging and monitoring fluid-saturated underground reservoirs

    DOEpatents

    Goloshubin, Gennady M.; Korneev, Valeri A.

    2006-11-14

    A method for identifying, imaging and monitoring dry or fluid-saturated underground reservoirs using seismic waves reflected from target porous or fractured layers is set forth. Seismic imaging the porous or fractured layer occurs by low pass filtering of the windowed reflections from the target porous or fractured layers leaving frequencies below low-most corner (or full width at half maximum) of a recorded frequency spectra. Additionally, the ratio of image amplitudes is shown to be approximately proportional to reservoir permeability, viscosity of fluid, and the fluid saturation of the porous or fractured layers.

  3. Seismic Monitoring with NetQuakes: The First 75 in the Pacific Northwest

    NASA Astrophysics Data System (ADS)

    Bodin, P.; Vidale, J. E.; Luetgert, J. H.; Malone, S. D.; Delorey, A. A.; Steele, W. P.; Gibbons, D. A.; Walsh, L. K.

    2011-12-01

    NetQuakes accelerographs are relatively inexpensive Internet-aware appliances that we are using as part of our regional seismic monitoring program in the Pacific Northwest Seismic Network (PNSN). To date we have deployed approximately 65 units. By the end of 2011, we will have at least 75 systems sited and operating. The instruments are made by Swiss manufacturer GeoSig, Ltd., and have been obtained by PNSN through several cooperative programs with the US Geological Survey (USGS). The NetQuakes systems have increased the number of strong-motion stations in the Pacific Northwest by ~50%. NetQuakes instruments connect to the Internet via wired or wireless telemetry, obtain accurate timing vie Network Time Protocol, and are designed to be located in the ground floor of houses or small buildings. At PNSN we have concentrated on finding NetQuakes hosts by having technologically savvy homeowners self-identify as a response to news reports about the NetQuakes project. Potential hosts are prioritized by their proximity to target sites provided by a regional panel of experts who studied the region's strong-ground-motion monitoring needs. Recorded waveforms, triggered by strong motion or retrieved from a buffer of continuous data, are transmitted to Menlo Park, and then on to PNSN in Seattle. Data are available with latency of a few minutes to a little over an hour, and are automatically incorporated with the rest of PNSN network data for analysis and the generation of earthquake products. Triggered data may also be viewed by the public via the USGS website, [http://earthquake.usgs.gov/monitoring/netquakes/map/pacnw]. We present examples of ground motion recordings returned to date. Local earthquakes up to M4 (at a distance of ~60 km) reveal interesting patterns of local site effects. The 11 March M9 Tohoku, Japan earthquake produced ground motions recorded on the PNSN accelerographs, including many NetQuakes systems, that reveal the extent and severity of basin

  4. The Seismic Aftershock Monitoring System (SAMS) for OSI - Experiences from IFE14

    NASA Astrophysics Data System (ADS)

    Gestermann, Nicolai; Sick, Benjamin; Häge, Martin; Blake, Thomas; Labak, Peter; Joswig, Manfred

    2016-04-01

    An on-site inspection (OSI) is the third of four elements of the verification regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The sole purpose of an OSI is to confirm whether a nuclear weapon test explosion or any other nuclear explosion has been carried out in violation of the treaty and to gather any facts which might assist in identifying any possible violator. It thus constitutes the final verification measure under the CTBT if all other available measures are not able to confirm the nature of a suspicious event. The Provisional Technical Secretariat (PTS) carried out the Integrated Field Exercise 2014 (IFE14) in the Dead Sea Area of Jordan from 3 November to 9. December 2014. It was a fictitious OSI whose aim was to test the inspection capabilities in an integrated manner. The technologies allowed during an OSI are listed in the Treaty. The aim of the Seismic Aftershock Monitoring System (SAMS) is to detect and localize aftershocks of low magnitudes of the triggering event or collapses of underground cavities. The locations of these events are expected in the vicinity of a possible previous explosion and help to narrow down the search area within an inspection area (IA) of an OSI. The success of SAMS depends on the main elements, hardware, software, deployment strategy, the search logic and not least the effective use of personnel. All elements of SAMS were tested and improved during the Built-Up Exercises (BUE) which took place in Austria and Hungary. IFE14 provided more realistic climatic and hazardous terrain conditions with limited resources. Significant variations in topography of the IA of IFE14 in the mountainous Dead Sea Area of Jordan led to considerable challenges which were not expected from experiences encountered during BUE. The SAMS uses mini arrays with an aperture of about 100 meters and with a total of 4 elements. The station network deployed during IFE14 and results of the data analysis will be presented. Possible aftershocks of

  5. Real-time seismic monitoring of the integrated cape girardeau bridge array and recorded earthquake response

    USGS Publications Warehouse

    Celebi, M.

    2006-01-01

    This paper introduces the state of the art, real-time and broad-band seismic monitoring network implemented for the 1206 m [3956 ft] long, cable-stayed Bill Emerson Memorial Bridge in Cape Girardeau (MO), a new Mississippi River crossing, approximately 80 km from the epicentral region of the 1811-1812 New Madrid earthquakes. The bridge was designed for a strong earthquake (magnitude 7.5 or greater) during the design life of the bridge. The monitoring network comprises a total of 84 channels of accelerometers deployed on the superstructure, pier foundations and at surface and downhole free-field arrays of the bridge. The paper also presents the high quality response data obtained from the network. Such data is aimed to be used by the owner, researchers and engineers to assess the performance of the bridge, to check design parameters, including the comparison of dynamic characteristics with actual response, and to better design future similar bridges. Preliminary analyses of ambient and low amplitude small earthquake data reveal specific response characteristics of the bridge and the free-field. There is evidence of coherent tower, cable, deck interaction that sometimes results in amplified ambient motions. Motions at the lowest tri-axial downhole accelerometers on both MO and IL sides are practically free from any feedback from the bridge. Motions at the mid-level and surface downhole accelerometers are influenced significantly by feedback due to amplified ambient motions of the bridge. Copyright ASCE 2006.

  6. A western gray whale mitigation and monitoring program for a 3-D seismic survey, Sakhalin Island, Russia.

    PubMed

    Johnson, S R; Richardson, W J; Yazvenko, S B; Blokhin, S A; Gailey, G; Jenkerson, M R; Meier, S K; Melton, H R; Newcomer, M W; Perlov, A S; Rutenko, S A; Würsig, B; Martin, C R; Egging, D E

    2007-11-01

    The introduction of anthropogenic sounds into the marine environment can impact some marine mammals. Impacts can be greatly reduced if appropriate mitigation measures and monitoring are implemented. This paper concerns such measures undertaken by Exxon Neftegas Limited, as operator of the Sakhalin-1 Consortium, during the Odoptu 3-D seismic survey conducted during 17 August-9 September 2001. The key environmental issue was protection of the critically endangered western gray whale (Eschrichtius robustus), which feeds in summer and fall primarily in the Piltun feeding area off northeast Sakhalin Island. Existing mitigation and monitoring practices for seismic surveys in other jurisdictions were evaluated to identify best practices for reducing impacts on feeding activity by western gray whales. Two buffer zones were established to protect whales from physical injury or undue disturbance during feeding. A 1 km buffer protected all whales from exposure to levels of sound energy potentially capable of producing physical injury. A 4-5 km buffer was established to avoid displacing western gray whales from feeding areas. Trained Marine Mammal Observers (MMOs) on the seismic ship Nordic Explorer had the authority to shut down the air guns if whales were sighted within these buffers. Additional mitigation measures were also incorporated: Temporal mitigation was provided by rescheduling the program from June-August to August-September to avoid interference with spring arrival of migrating gray whales. The survey area was reduced by 19% to avoid certain waters <20 m deep where feeding whales concentrated and where seismic acquisition was a lower priority. The number of air guns and total volume of the air guns were reduced by about half (from 28 to 14 air guns and from 3,390 in(3) to 1,640 in(3)) relative to initial plans. "Ramp-up" (="soft-start") procedures were implemented. Monitoring activities were conducted as needed to implement some mitigation measures, and to assess

  7. Active and passive electrical and seismic time-lapse monitoring of earthen embankments

    NASA Astrophysics Data System (ADS)

    Rittgers, Justin Bradley

    In this dissertation, I present research involving the application of active and passive geophysical data collection, data assimilation, and inverse modeling for the purpose of earthen embankment infrastructure assessment. Throughout the dissertation, I identify several data characteristics, and several challenges intrinsic to characterization and imaging of earthen embankments and anomalous seepage phenomena, from both a static and time-lapse geophysical monitoring perspective. I begin with the presentation of a field study conducted on a seeping earthen dam, involving static and independent inversions of active tomography data sets, and self-potential modeling of fluid flow within a confined aquifer. Additionally, I present results of active and passive time-lapse geophysical monitoring conducted during two meso-scale laboratory experiments involving the failure and self-healing of embankment filter materials via induced vertical cracking. Identified data signatures and trends, as well as 4D inversion results, are discussed as an underlying motivation for conducting subsequent research. Next, I present a new 4D acoustic emissions source localization algorithm that is applied to passive seismic monitoring data collected during a full-scale embankment failure test. Acoustic emissions localization results are then used to help spatially constrain 4D inversion of collocated self-potential monitoring data. I then turn to time-lapse joint inversion of active tomographic data sets applied to the characterization and monitoring of earthen embankments. Here, I develop a new technique for applying spatiotemporally varying structural joint inversion constraints. The new technique, referred to as Automatic Joint Constraints (AJC), is first demonstrated on a synthetic 2D joint model space, and is then applied to real geophysical monitoring data sets collected during a full-scale earthen embankment piping-failure test. Finally, I discuss some non-technical issues related to

  8. Installation of a digital, wireless, strong-motion network for monitoring seismic activity in a western Colorado coal mining region

    SciTech Connect

    Peter Swanson; Collin Stewart; Wendell Koontz

    2007-01-15

    A seismic monitoring network has recently been installed in the North Fork Valley coal mining region of western Colorado as part of a NIOSH mine safety technology transfer project with two longwall coal mine operators. Data recorded with this network will be used to characterize mining related and natural seismic activity in the vicinity of the mines and examine potential hazards due to ground shaking near critical structures such as impoundment dams, reservoirs, and steep slopes. Ten triaxial strong-motion accelerometers have been installed on the surface to form the core of a network that covers approximately 250 square kilometers (100 sq. miles) of rugged canyon-mesa terrain. Spread-spectrum radio networks are used to telemeter continuous streams of seismic waveform data to a central location where they are converted to IP data streams and ported to the Internet for processing, archiving, and analysis. 4 refs.

  9. Passive seismic monitoring of natural and induced earthquakes: case studies, future directions and socio-economic relevance

    USGS Publications Warehouse

    Bohnhoff, Marco; Dresen, Georg; Ellsworth, William L.; Ito, Hisao; Cloetingh, Sierd; Negendank, Jörg

    2010-01-01

    An important discovery in crustal mechanics has been that the Earth’s crust is commonly stressed close to failure, even in tectonically quiet areas. As a result, small natural or man-made perturbations to the local stress field may trigger earthquakes. To understand these processes, Passive Seismic Monitoring (PSM) with seismometer arrays is a widely used technique that has been successfully applied to study seismicity at different magnitude levels ranging from acoustic emissions generated in the laboratory under controlled conditions, to seismicity induced by hydraulic stimulations in geological reservoirs, and up to great earthquakes occurring along plate boundaries. In all these environments the appropriate deployment of seismic sensors, i.e., directly on the rock sample, at the earth’s surface or in boreholes close to the seismic sources allows for the detection and location of brittle failure processes at sufficiently low magnitude-detection threshold and with adequate spatial resolution for further analysis. One principal aim is to develop an improved understanding of the physical processes occurring at the seismic source and their relationship to the host geologic environment. In this paper we review selected case studies and future directions of PSM efforts across a wide range of scales and environments. These include induced failure within small rock samples, hydrocarbon reservoirs, and natural seismicity at convergent and transform plate boundaries. Each example represents a milestone with regard to bridging the gap between laboratory-scale experiments under controlled boundary conditions and large-scale field studies. The common motivation for all studies is to refine the understanding of how earthquakes nucleate, how they proceed and how they interact in space and time. This is of special relevance at the larger end of the magnitude scale, i.e., for large devastating earthquakes due to their severe socio-economic impact.

  10. Instrumental networks for monitoring short-period tectonic motions in seismic zones

    NASA Astrophysics Data System (ADS)

    Bender, P. L.

    1981-01-01

    For some years the monitoring of crustal movements in seismic zones has consisted mainly of periodic resurvey measurements using triangulation, trilateration, leveling, and gravity measurements. The frequency of remeasurements has been limited by the costs. Some fixed instruments have contributed also, such as creepmeters, tidegages, and devices for measuring tilts in lake levels. A number of inexpensive, shallow-borehole tiltmeters were installed recently in the U.S.A., but so far the noise level due to local ground motions appears to be fairly high for many instruments. Volumetric strainmeters are being used in several countries. 700 meter long laser strainmeters and a superconducting gravimeter have been in operation for several years at one site in California. Other simpler strainmeters and tiltmeters exist at a number of locations in seismic zones. Recently there has been increased interest both in trying to obtain frequent observations with fixed instruments and in reducing the noise level. Long-baseline liquid tiltmeters, deep-borehole tiltmeters, superconducting gravimeters, multi-wavelength laser distance-measuring devices, and laser strainmeters are capable of improved accuracy. However, they are more expensive than most previously used instruments. An additional future possibility is to use signals from the Global Positioning System (GPS) satellites to monitor networks of points. The accuracy would be limited almost completely by uncertainty in the water-vapor corrections along the various satellite-to-ground propagation paths. It seems possible that 1 cm accuracy for detecting baseline changes with very low false alarm rates can be achieved by using water-vapor radiometers at many of the sites, provided that sufficient accuracy can be achieved with the radiometers. Highly mobile instruments are being constructed in the U.S.A. which will use the spread-spectrum GPS signals as noise sources for long baseline radio interferometry. Initial tests using the

  11. Progress in using real-time GPS for seismic monitoring of the Cascadia megathrust

    NASA Astrophysics Data System (ADS)

    Szeliga, W. M.; Melbourne, T. I.; Santillan, V. M.; Scrivner, C.; Webb, F.

    2014-12-01

    We report on progress in our development of a comprehensive real-time GPS-based seismic monitoring system for the Cascadia subduction zone. This system is based on 1 Hz point position estimates computed in the ITRF08 reference frame. Convergence from phase and range observables to point position estimates is accelerated using a Kalman filter based, on-line stream editor. Positions are estimated using a short-arc approach and algorithms from JPL's GIPSY-OASIS software with satellite clock and orbit products from the International GNSS Service (IGS). The resulting positions show typical RMS scatter of 2.5 cm in the horizontal and 5 cm in the vertical with latencies below 2 seconds. To facilitate the use of these point position streams for applications such as seismic monitoring, we broadcast real-time positions and covariances using custom-built streaming software. This software is capable of buffering 24-hour streams for hundreds of stations and providing them through a REST-ful web interface. To demonstrate the power of this approach, we have developed a Java-based front-end that provides a real-time visual display of time-series, vector displacement, and contoured peak ground displacement. We have also implemented continuous estimation of finite fault slip along the Cascadia megathrust using an NIF approach. The resulting continuous slip distributions are combined with pre-computed tsunami Green's functions to generate real-time tsunami run-up estimates for the entire Cascadia coastal margin. This Java-based front-end is available for download through the PANGA website. We currently analyze 80 PBO and PANGA stations along the Cascadia margin and are gearing up to process all 400+ real-time stations operating in the Pacific Northwest, many of which are currently telemetered in real-time to CWU. These will serve as milestones towards our over-arching goal of extending our processing to include all of the available real-time streams from the Pacific rim. In addition

  12. Big Data Architectures for Operationalized Seismic and Subsurface Monitoring and Decision Support Workflows

    NASA Astrophysics Data System (ADS)

    Irving, D. H.; Rasheed, M.; Hillman, C.; O'Doherty, N.

    2012-12-01

    Oilfield management is moving to a more operational footing with near-realtime seismic and sensor monitoring governing drilling, fluid injection and hydrocarbon extraction workflows within safety, productivity and profitability constraints. To date, the geoscientific analytical architectures employed are configured for large volumes of data, computational power or analytical latency and compromises in system design must be made to achieve all three aspects. These challenges are encapsulated by the phrase 'Big Data' which has been employed for over a decade in the IT industry to describe the challenges presented by data sets that are too large, volatile and diverse for existing computational architectures and paradigms. We present a data-centric architecture developed to support a geoscientific and geotechnical workflow whereby: ●scientific insight is continuously applied to fresh data ●insights and derived information are incorporated into engineering and operational decisions ●data governance and provenance are routine within a broader data management framework Strategic decision support systems in large infrastructure projects such as oilfields are typically relational data environments; data modelling is pervasive across analytical functions. However, subsurface data and models are typically non-relational (i.e. file-based) in the form of large volumes of seismic imaging data or rapid streams of sensor feeds and are analysed and interpreted using niche applications. The key architectural challenge is to move data and insight from a non-relational to a relational, or structured, data environment for faster and more integrated analytics. We describe how a blend of MapReduce and relational database technologies can be applied in geoscientific decision support, and the strengths and weaknesses of each in such an analytical ecosystem. In addition we discuss hybrid technologies that use aspects of both and translational technologies for moving data and analytics

  13. Seismic array observations for monitoring phreatic eruptions in Iwojima Island, Japan

    NASA Astrophysics Data System (ADS)

    Ueda, H.; Kawaguchi, R.; Chiba, K.; Fujita, E.; Tanada, T.

    2015-12-01

    Iwojima is an active volcanic island located within a 10 km wide submarine caldera about 1250 km to the south of Tokyo, Japan. The volcanic activity is characterized by intensive earthquake activity associated with an island-wide uplift with high uplift rate (30~40 cm/year) and hydrothermal activity. In the last 10 years, phreatic eruptions took place in and near the island in 2012, 2013, and 2015. In such restless volcano, predictions and detections of occurrence points of phreatic eruptions are important for ensuring safety of residents. In the previous studies, we found that the earthquake activity of Iwojima highly correlates with the island wide large uplift, but the precursory activity of the phreatic eruption in 2012 was deviated from the correlation (Ueda et al. 2013 AGU Fall Meeting). For prediction of occurrence points of phreatic eruptions and investigation of the eruption mechanism, we began observation by seismic arrays at two areas in December 2014. The seismic arrays enable to locate epicenters of volcanic tremors, which are not well located by existing seismic stations. In May and June 2015, Japan Maritime Self-Defense Force stayed in Iwojima and a live camera of Japan Meteorological Agency found very small phreatic eruptions occurred at the northern beach. Existing seismic stations could not detect seismic signals related with the eruptions. The seismic array could detect weak seismic signals related with the eruptions. Although the seismic arrays could not detect precursory signals because of too small eruption, we expect the seismic arrays can detect precursory seismic signals suggesting occurrence points of small or medium-sized phreatic eruptions. The seismic arrays also detected epicenters of harmonic and monotonic tremors took place at an active fumarolic field in the north earthen part of Iwojima. The apparent velocity of seismic waves (~1km/s) strongly suggests that the tremors relate with hydrothermal activity near ground surface.

  14. Perspectives of Cross-Correlation in Seismic Monitoring at the International Data Centre

    NASA Astrophysics Data System (ADS)

    Bobrov, Dmitry; Kitov, Ivan; Zerbo, Lassina

    2014-03-01

    We demonstrate that several techniques based on waveform cross-correlation are able to significantly reduce the detection threshold of seismic sources worldwide and to improve the reliability of arrivals by a more accurate estimation of their defining parameters. A master event and the events it can find using waveform cross-correlation at array stations of the International Monitoring System (IMS) have to be close. For the purposes of the International Data Centre (IDC), one can use the spatial closeness of the master and slave events in order to construct a new automatic processing pipeline: all qualified arrivals detected using cross-correlation are associated with events matching the current IDC event definition criteria (EDC) in a local association procedure. Considering the repeating character of global seismicity, more than 90 % of events in the reviewed event bulletin (REB) can be built in this automatic processing. Due to the reduced detection threshold, waveform cross-correlation may increase the number of valid REB events by a factor of 1.5-2.0. Therefore, the new pipeline may produce a more comprehensive bulletin than the current pipeline—the goal of seismic monitoring. The analysts' experience with the cross correlation event list (XSEL) shows that the workload of interactive processing might be reduced by a factor of two or even more. Since cross-correlation produces a comprehensive list of detections for a given master event, no additional arrivals from primary stations are expected to be associated with the XSEL events. The number of false alarms, relative to the number of events rejected from the standard event list 3 (SEL3) in the current interactive processing—can also be reduced by the use of several powerful filters. The principal filter is the difference between the arrival times of the master and newly built events at three or more primary stations, which should lie in a narrow range of a few seconds. In this study, one event at a

  15. INL Seismic Monitoring Annual Report: January 1, 2012 - December 31, 2012

    SciTech Connect

    Payne, S. J.; Bruhn, D. F.; Hodges, J. M.; Berg, R. G.

    2015-03-01

    During 2012, the Idaho National Laboratory Seismic Monitoring Program evaluated 17,329 independent triggers that included earthquakes from around the world, the western United States, and local region of the Snake River Plain. Seismologists located 1,460 earthquakes and man-made blasts within and near the 161-km (or 100-mile) radius of the Idaho National Laboratory. Of these earthquakes, 16 had small-to-moderate size magnitudes (M) from 3.0 to 3.6. Within the 161-km radius, the majority of 695 earthquakes (M < 3.6) occurred in the active regions of the Basin and Range Provinces adjacent to the eastern Snake River Plain. Only 11 microearthquakes occurred within the Snake River Plain, four of which occurred in Craters of the Moon National Monument. The earthquakes had magnitudes from 1.0 to 1.7 and occurred at deep depths (11-24 km). Two events with magnitudes less than 1.0 occurred within the Idaho National Laboratory boundaries and had depths less than 10 km.

  16. INL Seismic Monitoring Annual Report: January 1, 2008 – December 31, 2008

    SciTech Connect

    S. J. Payne; N. S. Carpenter; J. M. Hodges; R. G. Berg

    2009-09-01

    During 2008, the INL Seismic Monitoring Program evaluated 7,284 earthquakes from around the world, the western United States, and local region of the eastern Snake River Plain. 2,396 earthquakes and man-made blasts were evaluated within the local region outside and within a 161-km (or 100-mile) radius of INL. Of these events, 25 were small to moderate size earthquakes ranging in magnitude from 3.0 to 3.9. 823 earthquakes occurred within the 161-km radius of INL and over 300 events were associated with eight different earthquake swarms which were located in active regions of the Basin and Range Province that surrounds the eastern Snake River Plain. Eight microearthquakes in 2008 of magnitude (M) 2.0 and less were located within the eastern Snake River Plain, seven at or near the Craters of the Moon National Monument and one within the INL boundary. Further analyses of the anomalously deep focal depths (15 to 42 km) and different waveform characteristics of all Craters of the Moon National Monument events (1999-2008) suggest association with magmatic processes. From 1972 to 2008, INL located 36 other small-magnitude microearthquakes (M < 2.0) at depths (< 11 km) within the eastern Snake River Plain and attributes these events to regional tectonic tensional stresses.

  17. INL Seismic Monitoring Annual Report: January 1, 2010 – December 31, 2010

    SciTech Connect

    N. Seth Carpenter; Suzette J. Payne; Jed M. Hodges; Robert G. Berg

    2011-09-01

    During 2010, the INL Seismic Monitoring Program evaluated 11,606 earthquakes from around the world, the western United States, and local region of the eastern Snake River Plain (ESRP). INL located 2,085 earthquakes and man-made blasts within the local region outside and within a 161-km (or 100-mile) radius of INL. Of these events, 53 were small-to-moderate size earthquakes ranging in magnitude from 3.0 to 4.8. 672 earthquakes occurred within the 161-km radius of INL and the majority of these earthquakes were located in active regions of the Basin and Range Province that surrounds the ESRP. There were 10 microearthquakes within the boundary of the ESRP, all of magnitude less than or equal to 2.0. Five of those were located within and near the ESRP at Craters of the Moon National Monument (COM) at mid- and lower-crust depths and are interpreted to be related to fluid movement. Since 1972, INL has recorded 48 small-magnitude, microearthquakes (M = 2.2) within the ESRP (not including COM events) and 22 deep microearthquakes (M = 2.3) in the vicinity of Craters of the Moon National Monument.

  18. INL Seismic Monitoring Annual Report: January 1, 2011 - December 31, 2011

    SciTech Connect

    S. J. Payne; J. M. Hodges; R. G. Berg; D. F. Bruhn

    2012-12-01

    During 2011, the Idaho National Laboratory Seismic Monitoring Program evaluated 21,928 independent triggers that included earthquakes from around the world, the western United States, and local region of the Snake River Plain. Seismologists located 2,063 earthquakes and man-made blasts within and near the 161-km (or 100-mile) radius of the Idaho National Laboratory. Of these events, 16 were small-to-moderate size earthquakes ranging in magnitude (M) from 3.0 to 4.4. Within the 161-km radius, the majority of 941 earthquakes (M < 4.4) occurred in the active regions of the Basin and Range Province with only six microearthquakes occurring in the Snake River Plain. In the northern and southeastern Basin and Range, eight earthquake swarms occurred and included over 325 events. Five of the Snake River Plain earthquakes were located within and near the northern and southern ends of the Great Rift volcanic rift zone. All have anomalously deep focal depths (16 to 38 km) and waveforms indicative of fluid movement at mid- and lower-crustal levels and are a continuation of activity observed at Craters of the Moon National Monument since 2007. Since 1972, the Idaho National Laboratory has recorded 55 small-magnitude microearthquakes (M = 2.2) within the eastern Snake River Plain and 25 deep microearthquakes (M = 2.3) in the vicinity of Craters of the Moon National Monument.

  19. Seismic Monitoring To Assess Performance Of Structures In Near-Real Time: Recent Progress

    SciTech Connect

    Celebi, Mehmet

    2008-07-08

    Earlier papers have described how observed data from classical accelerometers deployed in structures or from differential GPS with high sampling ratios deployed at roofs of tall buildings can be configured to establish seismic health monitoring of structures. In these configurations, drift ratios{sup 1} are the main parametric indicator of damage condition of a structure or component of a structure.Real-time measurement of displacements are acquired either by double integration of accelerometer time-series data, or by directly using GPS. Recorded sensor data is then related to the performance level of a building. Performance-based design method stipulates that for a building the amplitude of relative displacement of the roof of a building (with respect to its base) indicates its performance.Usually, drift ratio is computed using relative displacement between two consecutive floors. When accelerometers are used, a specific software is used to compute displacements and drift ratios in realtime by double integration of accelerometer data from several floors. However, GPS-measured relative displacements are limited to being acquired only at the roof with respect to its reference base. Thus, computed drift ratio is the average drift ratio for the whole building. Until recently, the validity of measurements using GPS was limited to long-period structures (T>1 s) because GPS systems readily available were limited to 10-20 samples per seconds (sps) capability. However, presently, up to 50 sps differential GPS systems are available on the market and have been successfully used to monitor drift ratios [1,2]--thus enabling future usefulness of GPS to all types of structures. Several levels of threshold drift ratios can be postulated in order to make decisions for inspections and/or occupancy.Experience with data acquired from both accelerometers and GPS deployments indicates that they are reliable and provide pragmatic alternatives to alert the owners and other authorized

  20. Seismic Monitoring To Assess Performance Of Structures In Near-Real Time: Recent Progress

    NASA Astrophysics Data System (ADS)

    Ćelebi, Mehmet

    2008-07-01

    Earlier papers have described how observed data from classical accelerometers deployed in structures or from differential GPS with high sampling ratios deployed at roofs of tall buildings can be configured to establish seismic health monitoring of structures. In these configurations, drift ratios1 are the main parametric indicator of damage condition of a structure or component of a structure. Real-time measurement of displacements are acquired either by double integration of accelerometer time-series data, or by directly using GPS. Recorded sensor data is then related to the performance level of a building. Performance-based design method stipulates that for a building the amplitude of relative displacement of the roof of a building (with respect to its base) indicates its performance. Usually, drift ratio is computed using relative displacement between two consecutive floors. When accelerometers are used, a specific software is used to compute displacements and drift ratios in realtime by double integration of accelerometer data from several floors. However, GPS-measured relative displacements are limited to being acquired only at the roof with respect to its reference base. Thus, computed drift ratio is the average drift ratio for the whole building. Until recently, the validity of measurements using GPS was limited to long-period structures (T>1 s) because GPS systems readily available were limited to 10-20 samples per seconds (sps) capability. However, presently, up to 50 sps differential GPS systems are available on the market and have been successfully used to monitor drift ratios [1,2]—thus enabling future usefulness of GPS to all types of structures. Several levels of threshold drift ratios can be postulated in order to make decisions for inspections and/or occupancy. Experience with data acquired from both accelerometers and GPS deployments indicates that they are reliable and provide pragmatic alternatives to alert the owners and other authorized

  1. The ADN project : an integrated seismic monitoring of the northern Ecuadorian subduction

    NASA Astrophysics Data System (ADS)

    Nocquet, Jean-Mathieu; Yepes, Hugo; Vallee, Martin; Mothes, Patricia; Regnier, Marc; Segovia, Monica; Font, Yvonne; Vaca, Sandro; Bethoux, Nicole; Ramos, Cristina

    2010-05-01

    The subduction of the Nazca plate beneath South America has caused one of the largest megathrust earthquake sequence during the XXth century with three M>7.7 earthquakes that followed the great 1906 (Mw = 8.8) event. Better understanding the processes leading to the occurrence of large subduction earthquakes requires to monitor the ground motion over a large range of frequencies. We present a new network (ADN) developed under a collaboration between the IRD-GeoAzur (Nice, France) and the IG-EPN (Quito, Ecuador). Each station of the ADN network includes a GPS recording at 5 Hz, an accelerometer and a broadband seismometer. CGPS data will quantify the secular deformation induced by elastic locking along the subduction interface, enabling a detailed modelling of the coupling distribution. CGPS will be used to monitor any transient deformation induced by Episodic Slip Event along the subduction, together with broadband seismometers that can detect any tremors or seismic signatures that may accompany them. In case of any significant earthquake, 5 Hz GPS and accelerometer will provide near field data for earthquake source detailed study. Finally, the broadband seismometers will be used for study of the microseismicity and structure of the subduction zone. The network includes 9 stations, operating since 2008 and covering the coastal area from latitude 1.5°S to the Colombian border. In this poster, we will present preliminary assessment of the data, first hypocenters location, magnitude and focal mechanism determination, as well as results about an episodic slip event detected in winter 2008.

  2. Local Technical Resources for Development of Seismic Monitoring in Caucasus and Central Asia - GMSys2009 Data Acquisition System

    NASA Astrophysics Data System (ADS)

    Chkhaidze, D.; Basilaia, G.; Elashvili, M.; Shishlov, D.; Bidzinashvili, G.

    2012-12-01

    Caucasus and Central Asia represents regions of high seismic activity, composing a significant part of Alpine-Himalayan continental collision zone. Natural catastrophic events cause significant damage to the infrastructure worldwide, among these approximately ninety percent of the annual loss is due to earthquakes. Monitoring of Seismic Activity in these regions and adequate assessment of Seismic Hazards represents indispensible condition for safe and stable development. Existence of critical engineering constructions in the Caucasus and Central Asia such as oil and gas pipelines, high dams and nuclear power plants dramatically raises risks associated with natural hazards and eliminates necessity of proper monitoring systems. Our initial efforts were focused on areas that we are most familiar; the geophysical community in the greater Caucuses and Central Asia experiencing many of the same problems with the monitoring equipment. As a result, during the past years GMSys2009 was develop at the Institute of Earth Sciences of Ilia State University. Equipment represents a cost-effective, multifunctional Geophysical Data Acquisition System (DAS) to monitor seismic waves propagating in the earth and related geophysical parameters. Equipment best fits local requirements concerning power management, environmental protection and functionality, the same time competing commercial units available on the market. During past several years more than 30 units were assembled and what is most important installed in Georgia, Armenia, Azerbaijan and Tajikistan. GMSys2009 utilizes standard MiniSEED data format and data transmission protocols, making it possible online waveform data sharing between the neighboring Countries in the region and international community. All the mentioned installations were technically supported by the group of engineers from the Institute of Earth Sciences, on site trainings for local personnel in Armenia, Azerbaijan and Tajikistan was provided creating a

  3. Can Inter-seismic/Pre-seismic Deformation be Monitored With PSInSAR? An Example From the Lower Tagus Valley, Portugal

    NASA Astrophysics Data System (ADS)

    Fonseca, J. F.; Ferretti, A.; Heleno, S. I.; Falcao, A. P.

    2006-12-01

    Although Reid's elastic rebound model captured the essence of earthquake generation nearly one century ago, early enthusiasm about the predictability of earthquake rupture through geodetic monitoring quickly faded away. In the 90's, it became apparent that fault interaction through stress transfer was an additional factor of complexity. However, a clearer relationship between observed strain and time before next rupture may exist in the case of slow moving intraplate faults, with the added advantage that such ruptures usually have larger stress drops, hence possibly larger pre-seismic strains. The Lower Tagus Valley (LTV) fault of SW Portugal has significant historical seismicity (probable M7 in 1356 and 1531, possible M7 triggered rupture in 1755, M6 in 1909), but currently does not display seismic activity. The LTV fault is the SE limit of the Lusitanian Basin, a Triassic aborted rift, and this seismic activity indicates that the convergence between Africa and Eurasia is accommodated preferentially in the weak lithosphere that is characteristic of this type of setting. In the framework of ESA project GMES TERRAFIRMA, we tested the use of PSInSAR as a tool to detect surface deformation resulting from asseismic slip below the seismogenic crust. We analysed 200196 permanent scatterers (PS) around the SW tip of the LTV fault, at a density of 250 points per Km2 , and smoothed the resulting line-of-sight velocities to separate individual PS behaviour from ground motion. We checked this deformation pattern against conventional surveying (high precision re-leveling), continuous GPS and tide gauge data. Uplift in the Lusitanian Basin was detected by the PSInSAR data and supported by re-leveling, GPS and tide gauge data. Regions of subsidence were also detected, and we use piezometric data to investigate the possible contribution of groundwater level fluctuations. The deformation pattern detected by the PSInSAR data seems to have a tectonic origin. It can be modeled as the

  4. Simultaneous seismic and geotechnical monitoring for the characterization of superficial deformations of the mudslide in Super-Sauze, French Alps

    NASA Astrophysics Data System (ADS)

    Walter, Marco; Joswig, Manfred; Arnhardt, Christian; Malet, Jean-Philippe

    2010-05-01

    To characterize superficial deformations of the mudslide in Super-Sauze, southern French Alps, seismic and geotechnical monitoring techniques have been applied simultaneously during a field campaign in July 2009. Based on the method nanoseismic monitoring (Joswig, 2008), we installed three seismic mini-arrays with an aperture of 25-30m, each one consisting of one three-component central-station and three outer vertical-component stations. We identified two different deformation processes caused by the movement of the mudslide: fracture processes within the slope material and superficial fissure development (Walter & Joswig, 2009). The spatiotemporal occurrence of deformation processes identified by nanoseismic monitoring has been verified with geotechnical monitoring systems. GPS devices as well as a small wireless ad-hoc, multi hop sensor network (WSN) have been installed in the slope area. The network consist of 7 connection points, called nodes, that transfer data from different sensors via radio signal directly or over other nodes (Multi Hop) in real-time to a data collection point (gateway). To determine the varying deformation processes, like toppling, spreading, falling and sliding, 6 nodes were equipped with micro-sensors (each with 3-axis acceleration sensor, 2-axis tilt sensor and barometric pressure sensor). In order to monitor the deformation of a recent fissure, one node was equipped with a position-sensor (draw wire displacement transducer). Laboratory tests for the different sensors showed that tilt movements can be detected with an accuracy of +/- 0,06° and a resolution of >0,1°, accelerations with +/- 0,008g and >0,02g and displacements with +/- 0,1mm and >0,1mm. The analysis of data recorded by barometric pressure sensors is quite difficult due to the high natural pressure fluctuations in mountain areas, anyway, the detection of fluctuations of >0,5m was possible. Except the displacement transducers, the geotechnical sensors didn't detect any

  5. Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO2 Enhanced Oil Recovery Operations

    SciTech Connect

    Brian Toelle

    2008-11-30

    This project, 'Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO{sub 2} Enhanced Oil Recovery Operations', investigated the potential for monitoring CO{sub 2} floods in carbonate reservoirs through the use of standard p-wave seismic data. This primarily involved the use of 4D seismic (time lapse seismic) in an attempt to observe and map the movement of the injected CO{sub 2} through a carbonate reservoir. The differences between certain seismic attributes, such as amplitude, were used for this purpose. This technique has recently been shown to be effective in CO{sub 2} monitoring in Enhanced Oil Recovery (EOR) projects, such as Weyborne. This study was conducted in the Charlton 30/31 field in the northern Michigan Basin, which is a Silurian pinnacle reef that completed its primary production in 1997 and was scheduled for enhanced oil recovery using injected CO{sub 2}. Prior to injection an initial 'Base' 3D survey was obtained over the field and was then processed and interpreted. CO{sub 2} injection within the main portion of the reef was conducted intermittently during 13 months starting in August 2005. During this time, 29,000 tons of CO{sub 2} was injected into the Guelph formation, historically known as the Niagaran Brown formation. By September 2006, the reservoir pressure within the reef had risen to approximately 2000 lbs and oil and water production from the one producing well within the field had increased significantly. The determination of the reservoir's porosity distribution, a critical aspect of reservoir characterization and simulation, proved to be a significant portion of this project. In order to relate the differences observed between the seismic attributes seen on the multiple 3D seismic surveys and the actual location of the CO{sub 2}, a predictive reservoir simulation model was developed based on seismic attributes obtained from the base 3D seismic survey and available well data. This simulation predicted

  6. Active monitoring of upper crust using ACROSS-seismic array system

    NASA Astrophysics Data System (ADS)

    Misu, H.; Ikuta, R.; Watanabe, T.; Yamaoka, K.

    2004-12-01

    Temporal variations of S- and surface-wave travel times were continuously monitored using ACROSS source and seismic array. We made an experiment lasting 5 months at a site near the Nojima fault which ruptured during the 1995 Kobe earthquake (M7.2). Elastic waves generated by ACROSS vibrators are received by two seismic arrays. One is located at about 300m northwest and the other is about 300m southwest of the vibrators. Each array has an aperture size of about 50 m and consists of ten seismometers that are three component velocity sensors with natural frequency of 4.5Hz. In this experiment, we used solar-battery systems to enable the long-term experiment, and we succeeded in continuous data recording without any troubles. To obtain the signal in time domain, in which P, S and some later phases were included, we executed the following procedure in the frequency domain. We extracted the ACROSS signals from the every stacked data. The extracted signal was divided by the force which was generated by the source. In this study, we used the spectrum of the theoretical force calculated from the frequency-modulated rotation. We regarded the result as a transfer function (or band-limited impulse response) between the source and the receivers. Applying appropriate window function and inverse Fourier transformation, we could obtain S wave and big surface wave. To emphasize later part of ACROSS signal, we stacked the data of all N-array sensors for every one hour and transformed its envelope using Hilbert transformation. We may detect some phase around 8, 13, 16 -seconds in the envelope. There were a few candidates for a cause of the phases, random noise or coherent noise, or reflected signals from deeper portion of the crust. We examined these possibilities one by one. The phases were found all through the experiment period. Therefore they must not be due to random noises. Next, we synthesized transfer function between the vibrator and the seismic array to examine the effect

  7. Seismic Monitoring Prior to and During DFDP-2 Drilling, Alpine Fault, New Zealand: Matched-Filter Detection Testing and the Real-Time Monitoring System

    NASA Astrophysics Data System (ADS)

    Boese, C. M.; Chamberlain, C. J.; Townend, J.

    2015-12-01

    In preparation for the second stage of the Deep Fault Drilling Project (DFDP) and as part of related research projects, borehole and surface seismic stations were installed near the intended DFDP-2 drill-site in the Whataroa Valley from late 2008. The final four borehole stations were installed within 1.2 km of the drill-site in early 2013 to provide near-field observations of any seismicity that occurred during drilling and thus provide input into operational decision-making processes if required. The basis for making operational decisions in response to any detected seismicity had been established as part of a safety review conducted in early 2014 and was implemented using a "traffic light" system, a communications plan, and other operational documents. Continuous real-time earthquake monitoring took place throughout the drilling period, between September and late December 2014, and involved a team of up to 15 seismologists working in shifts near the drill-site and overseas. Prior to drilling, records from 55 local earthquakes and 14 quarry blasts were used as master templates in a matched-filter detection algorithm to test the capabilities of the seismic network for detecting seismicity near the drill site. The newly detected microseismicity was clustered near the DFDP-1 drill site at Gaunt Creek, 7.4 km southwest of DFDP-2. Relocations of these detected events provide more information about the fault geometry in this area. Although no detectable seismicity occurred within 5 km of the drill site during the drilling period, the region is capable of generating earthquakes that would have required an operational response had they occurred while drilling was underway (including a M2.9 event northwest of Gaunt Creek on 15 August 2014). The largest event to occur while drilling was underway was of M4.5 and occurred approximately 40 km east of the DFDP-2 drill site. In this presentation, we summarize the setup and operations of the seismic network and discuss key

  8. 4D Seismic Monitoring at the Ketzin Pilot Site during five years of storage - Results and Quantitative Assessment

    NASA Astrophysics Data System (ADS)

    Lüth, Stefan; Ivanova, Alexandra; Ivandic, Monika; Götz, Julia

    2015-04-01

    The Ketzin pilot site for geological CO2-storage has been operative between June 2008 and August 2013. In this period, 67 kt of CO2 have been injected (Martens et al., this conference). Repeated 3D seismic monitoring surveys were performed before and during CO2 injection. A third repeat survey, providing data from the post-injection phase, is currently being prepared for the autumn of 2015. The large scale 3D surface seismic measurements have been complemented by other geophysical and geochemical monitoring methods, among which are high-resolution seismic surface-downhole observations. These observations have been concentrating on the reservoir area in the vicinity of the injection well and provide high-resolution images as well as data for petrophysical quantification of the CO2 distribution in the reservoir. The Ketzin pilot site is a saline aquifer site in an onshore environment which poses specific challenges for a reliable monitoring of the injection CO2. Although much effort was done to ensure as much as possible identical acquisition conditions, a high degree of repeatability noise was observed, mainly due to varying weather conditions, and also variations in the acquisition geometries due to logistical reasons. Nevertheless, time-lapse processing succeeded in generating 3D time-lapse data sets which could be interpreted in terms of CO2 storage related amplitude variations in the depth range of the storage reservoir. The time-lapse seismic data, pulsed-neutron-gamma logging results (saturation), and petrophysical core measurements were interpreted together in order to estimate the amount of injected carbon dioxide imaged by the seismic repeat data. For the first repeat survey, the mass estimation was summed up to 20.5 ktons, which is approximately 7% less than what had been injected then. For the second repeat survey, the mass estimation was summed up to approximately 10-15% less than what had been injected. The deviations may be explained by several factors

  9. Uranium Groundwater Monitoring and Seismic Analysis: A Case Study of the Gran Sasso Hydrogeological Basin, Italy

    NASA Astrophysics Data System (ADS)

    Ciarletti, Marta; Plastino, Wolfango; Peresan, Antonella; Nisi, Stefano; Copia, Lorenzo; Panza, Giuliano F.; Povinec, Pavel P.

    2016-04-01

    Uranium groundwater anomalies, observed before the L'Aquila earthquake (April 6th, 2009) and before the seismic swarm, which occurred in the second half of 2010, represent a key geochemical signal of a progressive increase of deep fluids fluxes at middle-lower crustal levels associated with the geodynamics of the earthquake. In this paper, temporal variations of uranium groundwater are studied in association with the seismic pattern around Gran Sasso National Laboratory (LNGS-INFN). The normalized seismic energy release and the number of earthquakes are analyzed in detail by means of monthly sliding time windows. They are compared with uranium anomalies to highlight any possible correlation.

  10. Proceedings of the 21st Seismic Research Symposium: Technologies for Monitoring The Comprehensive Nuclear Test-Ban Treaty

    SciTech Connect

    Warren, N. Jill

    1999-09-21

    These proceedings contain papers prepared for the 21st Seismic Research Symposium: Technologies for Monitoring The Comprehensive Nuclear-Test-Ban Treaty, held 21-24 September 1999 in Las Vegas, Nevada. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), Air Force Technical Applications Center (AFTAC), Department of Defense (DoD), the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  11. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    SciTech Connect

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2005-09-01

    The objective of this research project is to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data to observe changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 18 months of seismic monitoring, one baseline and six monitor surveys clearly imaged changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators.

  12. 4-D High-Resolution Seismic Reflection Monitoring of Miscible CO2 Injected into a Carbonate Reservoir

    SciTech Connect

    Richard D. Miller; Abdelmoneam E. Raef; Alan P. Byrnes; William E. Harrison

    2006-08-31

    The objective of this research project is to acquire, process, and interpret multiple high-resolution 3-D compressional wave and 2-D, 2-C shear wave seismic data in an attempt to observe changes in fluid characteristics in an oil field before, during, and after the miscible carbon dioxide (CO{sub 2}) flood that began around December 1, 2003, as part of the DOE-sponsored Class Revisit Project (DOE DE-AC26-00BC15124). Unique and key to this imaging activity is the high-resolution nature of the seismic data, minimal deployment design, and the temporal sampling throughout the flood. The 900-m-deep test reservoir is located in central Kansas oomoldic limestones of the Lansing-Kansas City Group, deposited on a shallow marine shelf in Pennsylvanian time. After 30 months of seismic monitoring, one baseline and eight monitor surveys clearly detected changes that appear consistent with movement of CO{sub 2} as modeled with fluid simulators and observed in production data.

  13. Monitoring the Methane Hydrate Dissociation by the Offshore Methane Hydrate Production Tests using Multi-component Seismic

    NASA Astrophysics Data System (ADS)

    Asakawa, Eiichi; Hayashi, Tsutomu; Tsukahara, Hitoshi; Takahashi, Hiroo; Saeki, Tatsuo

    2013-04-01

    We developed a new OBC (Ocean Bottom Cable), named as 'DSS' (Deep-sea Seismic System). The sensor has 3-component accelerometer and a hydrophone applicable for four-component (4C) seismic survey. Using the DSS, the methane hydrate dissociation zone will be tried to be monitored at the water depth of around 1000m during JOGMEC offshore methane hydrate production test in early 2013. Before the DSS, we had developed the RSCS (Real-time Seismic Cable System) with 3-component gimbaled geophones, and carried out a reflection seismic survey in the Nankai Trough in 2006. Referring this successful survey, we improved the RSCS to the DSS. The receiver size is reduced to 2/3 and the receiver case has a protective metallic exterior and the cable is protected with steel-screened armouring, allowing burial usage using ROV for sub-seabed deployment at the water depth up to 2000m. It will realize a unique survey style that leaves the system on the seabed between pre-test baseline survey and post-test repeated surveys, which might be up to 6 months. The fixed location of the receiver is very important for time-lapse monitoring survey. The DSS has totally 36 sensors and the sensor spacing is 26.5m. The total length is about 1km. We carried out the pre-test baseline survey between off Atsumi and Shima-peninsula in August, 2012.We located the DSS close to the production test well. The nearest sensor is 63m apart from the well. A newly developed real-time 3-D laying simulation system consisting of ADCP (Acoustic Doppler Current Profiler), transponders attached to the DSS, and real-time 3-D plotting system for transponder locations have been adopted. After we laid the cable, we buried the DSS using ROV (Remotely Operated Vehicle). The baseline survey included 2D/3D seismic surveys with shooting vessel and cable laying/observation ship. The resultant 2D section and 3D volume shows the good quality to delineate the methane hydrate concentrated zone. After the baseline survey, we have left

  14. New Method of active electromagnetic induction and seismic Monitoring in Oil saturated Media

    NASA Astrophysics Data System (ADS)

    Hachay, Olga, ,, Prof.; Khachay, Oleg; Khachay, Andrey

    2014-05-01

    It is provided a comparison of no equilibrium effects by independent hydro dynamical and electromagnetic induction influence on an oil layer and the medium, which it surrounds. It is known, that by drainage and steeps the hysteresis effect on curves of the relative phase permeability in dependence from porous medium water saturation by some cycles of influence: drainage-steep-drainage is observed. In earlier papers the analysis of the seism acoustic monitoring data in regimes of phone radiation, response on the first influence of given frequency and on the second influence is developed. For the analysis of seism acoustic response in time on fixed intervals along the borehole an algorithm of phase diagrams of the state of many phase medium is suggested. On the base of developed algorithm a new algorithm of analyze of space, but integral in time for equal observation periods changing by the method of phase diagram state of many phase medium in the oil layer is developed. The developed method allows on quality level to classify the state of the polyphase medium, which is the oil layer, using data of many cycles influence. In that paper we suggest the algorithm of modeling of 2-d seismic field distribution in the heterogeneous medium with hierarchic inclusions. Using the developed earlier 3-d method of induction electromagnetic frequency geometric monitoring we showed the opportunity of defining of physical and structural features of hierarchic oil layer structure and estimating of water saturating by crack inclusions. That allows managing the process of drainage and steeping by water displacement the oil out of the layer. Thus, the developed methods allow on the quality and quantity levels to make a classification of the many phase medium, which is an oil layer, using data for multiple excitation. For quantitative solution of earlier listed events of no equilibrium and hysteretic interaction of water and oil by out working of the oil layer, it is urgently to add and

  15. Using the international monitoring system of seismic, infrasound, and hydroacoustic sensors for global airburst detection

    NASA Astrophysics Data System (ADS)

    Brown, P.

    2014-07-01

    The impact of meter-sized objects with the Earth occurs every few weeks [1,2]. Most of these collisions result in airbursts, here defined as impacts where the meteoroid's initial kinetic energy is of order a small nuclear weapon (> 0.1 kilotons of TNT equivalent = 4.185×10^{11} J) and where this energy is fully deposited at high altitude in the atmosphere. Historically, the majority of these airbursts go undetected over oceans or remote land areas as dedicated fireball camera networks (eg.[ 3]) cover less than 1 % of the globe. Airbursts often produce meteorite falls and hence airburst data may yield pre-atmospheric orbits and physical properties for the impacting NEO providing context for recovered meteorite samples [4]. With the advent of more capable telescopic survey systems, pre-atmospheric detection of NEO-producing airbursts has become possible as evidenced by the impacts of 2014 AA and 2008 TC_3 [5]. Detection of ''terminal plungers'' is expected to become more common as projects such as ATLAS [6] become operational. This increases the need for instrumental data of the corresponding airburst, particularly its location and energy. Beginning in the late 1990s, a global network of seismic, infrasound, and hydroacoustic sensors has been deployed globally to provide treaty verification for a nuclear test ban. This network is the International Monitoring System (IMS) overseen by Comprehensive Nuclear Test Ban Treaty Organisation (CTBTO) [7]. The IMS is a unique global resource for detection of explosions worldwide and in recent years shock waves from many airbursts [8] have been detected by the system. Data from the IMS permits airburst location, origin time and energy to be measured. In rare cases, source heights, trajectories, and details of fragmentation may be obtained. Here the current capabilities of the IMS will be presented in the context of airburst detection and characterization. Empirical characteristics of the long-range sound produced by airbursts

  16. Real-time monitoring of seismicity and deformation during the Bárdarbunga rifting event and associated caldera subsidence

    NASA Astrophysics Data System (ADS)

    Jónsdóttir, Kristín; Ófeigsson, Benedikt; Vogfjörd, Kristín; Roberts, Matthew; Barsotti, Sara; Gudmundsson, Gunnar; Hensch, Martin; Bergsson, Bergur; Kjartansson, vilhjálmur; Erlendsson, Pálmi; Friðriksdóttir, Hildur; Hreinsdóttir, Sigrún; Guðmundsson, Magnús; Sigmundsson, Freysteinn; Árnadóttir, Thóra; Heimisson, Elías; Hjorleifsdóttir, Vala; Soring, Jón; Björnsson, Bogi; Oddsson, Björn

    2015-04-01

    We present a monitoring overview of a rifting event and associated caldera subsidence in a glaciated environment during the Bárðarbunga volcanic crisis. Following a slight increase in seismicity and a weak deformation signal, noticed a few months before the unrest by the SIL monitoring team, an intense seismic swarm began in the subglacial Bárðarbunga caldera on August 16 2014. During the following two weeks, a dyke intruded into the crust beneath the Vatnajökull ice cap, propagating 48 km from the caldera to the east-north-east and north of the glacier where an effusive eruption started in Holuhraun. The eruption is still ongoing at the time of writing and has become the largest eruption in over 200 years in Iceland. The dyke propagation was episodic with a variable rate and on several occasions low frequency seismic tremor was observed. Four ice cauldrons, manifestations of small subglacial eruptions, were detected. Soon after the swarm began the 7x11 km wide caldera started to subside and is still subsiding (although at slower rates) and has in total subsided over 60 meters. Unrest in subglacial volcanoes always calls for interdisciplinary efforts and teamwork plays a key role for efficient monitoring. Iceland has experienced six subglacial volcanic crises since modern digital monitoring started in the early 90s. With every crisis the monitoring capabilities, data interpretations, communication and information dissemination procedures have improved. The Civil Protection calls for a board of experts and scientists (Civil Protection Science Board, CPSB) to share their knowledge and provide up-to-date information on the current status of the volcano, the relevant hazards and most likely scenarios. The evolution of the rifting was monitored in real-time by the joint interpretation of seismic and cGPS data. The dyke propagation could be tracked and new, updated models of the dyke volume were presented at the CPSB meetings, often daily. In addition, deformation

  17. High-Resolution Time-Lapse Seismic Monitoring over Steam Injection: Rock Physics, Data Acquisition, and Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Bianco, E. M.; Schmitt, D. R.

    2008-12-01

    Steam is injected into porous formations both to mobilize heavy hydrocarbons in petroleum production and environmental remediation. This is an energy intensive process and remotely monitoring the movement of the steam has implications for the improving the economics, environmental impact, and even safety of a given steam injection process. Rock physics concepts suggest that such steam zones should be easily detected by seismic reflection techniques if the compressible gaseous steam replaces substantially less compressible liquid. To test this concept, a series of 11 repeated 2D seismic profiles were acquired over a 6 year period during steam injection to a petroleum reservoir. Care was taken in the repeatability of surface geophone and source positions, common midpoint traces were at a small spacing of only 1-m across an ~200 m profile. The three parallel steam zones at depths of only 120 m to 160 m were readily detected, and variations with time are seen. The observed signatures, however, cannot be explained by a simple 1-D convolutional seismic model. To overcome this limitation, a finely gridded 2D acoustic finite difference model of the background geology with the inclusion of three closely spaced steam zones was carried out and the data processed to create a 2D seismic reflection profile. The physical properties of the steam zone were developed considering pore and confining pressure, fluid saturation, temperature, and nonlinear rock frame effects. The numerical and observed profiles are similar in many respects and suggest that diffraction effects arising from the similarity of the dimensions of the steam zones to the illuminating seismic wavelengths must be considered in the analysis of such data. geo.phys.ualberta.ca/~ebianco

  18. Monitoring and Characterizing the Geysering and Seismic Activity at the Lusi Mud Eruption Site, East Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Karyono, Karyono; Obermann, Anne; Mazzini, Adriano; Lupi, Matteo; Syafri, Ildrem; Abdurrokhim, Abdurrokhim; Masturyono, Masturyono; Hadi, Soffian

    2016-04-01

    The Lusi eruption began on May 29, 2006 in the northeast of Java Island, Indonesia, and to date is still active. Lusi is a newborn sedimentary-hosted hydrothermal system characterized by continuous expulsion of liquefied mud and breccias and geysering activity. Lusi is located upon the Watukosek fault system, a left lateral wrench system connecting the volcanic arc and the bakarc basin. This fault system is still periodically reactivated as shown by field data. In the framework of the Lusi Lab project (ERC grant n° 308126) we conducted several types of monitoring. Based on camera observations, we characterized the Lusi erupting activity by four main behaviors occurring cyclically: (1) Regular activity, which consists in the constant emission of water and mud breccias (i.e. viscous mud containing clay, silt, sand and clasts) associated with the constant expulsion of gas (mainly aqueous vapor with minor amounts of CO2 and CH4) (2) Geysering phase with intense bubbling, consisting in reduced vapor emission and more powerful bursting events that do not seem to have a regular pattern. (3) Geysering phase with intense vapor and degassing discharge and a typically dense plume that propagates up to 100 m height. (4) Quiescent phase marking the end of the geysering activity (and the observed cycle) with no gas emissions or bursts observed. To investigate the possible seismic activity beneath Lusi and the mechanisms controlling the Lusi pulsating behaviour, we deployed a network of 5 seismic stations and a HD camera around the Lusi crater. We characterize the observed types of seismic activity as tremor and volcano-tectonic events. Lusi tremor events occur in 5-10 Hz frequency band, while volcano tectonic events are abundant in the high frequencies range from 5 Hz until 25 Hz. We coupled the seismic monitoring with the images collected with the HD camera to study the correlation between the seismic tremor and the different phases of the geysering activity. Key words: Lusi

  19. Predicting High Frequency Wind-wave Generated Seismic Noise: a Way to Remotely Monitor Sea-ice Mechanical State.

    NASA Astrophysics Data System (ADS)

    Gimbert, F.; Tsai, V. C.

    2014-12-01

    environments, which is a topic of growing interest due to the role of ocean waves in the current decline of sea ice. We show that sea ice mechanical changes can be monitored at daily timescales using our framework. Our ongoing work consists in combining seismic observations with satellite observations of sea ice concentration and thickness to extract sea ice mechanical strength.

  20. Conformity assessment for seismic monitoring and reservoir simulation at the Ketzin pilot site - how much conformity can be reached?

    NASA Astrophysics Data System (ADS)

    Lüth, Stefan; Ivanova, Alexandra; Kempka, Thomas

    2016-04-01

    The EU CCS Directive defines three high-level criteria which have to be fulfilled by a site operator in the post closure phase of a storage site before liability can be transferred to the public after site closure. One of these high-level requirements is "Demonstrating conformity between observed and simulated plume behaviour". The observed plume behaviour is derived from geophysical and/or geochemical monitoring. Repeated 3D seismic observations have proven to provide the most comprehensive image of a CO2 plume in various projects such as Sleipner, Weyburn, or Ketzin. The simulated plume behaviour is derived from reservoir simulation using a model calibrated with monitoring results. Plume observations using any monitoring method are always affected by limited resolution and detection ability, and reservoir simulations will only be able to provide an approximated representation of the occurring reservoir processes. Therefore, full conformity between observed and simulated plume behaviour is difficult to achieve, if it is at all. It is therefore of crucial importance for each storage site to understand to what degree conformity can be achieved under realistic conditions, comprising noise affected monitoring data and reservoir models based on geological uncertainties. We applied performance criteria (plume footprint area, lateral migration distance, plume volume, and similarity index) for a comparison between monitoring results (4D seismic measurements) and reservoir simulations, considering a range of seismic amplitude values as noise threshold and a range of minimum thickness of the simulated CO2 plume. Relating the performance criteria to the noise and thickness threshold values allows assessing the quality of conformance between simulated and observed behaviour of a CO2 plume. The Ketzin site is provided with a comprehensive monitoring data set and a history-matched reservoir model. Considering the relatively high noise level, which is inherent for land

  1. Seismic analysis of the 13 October 2012 Te Maari, New Zealand, lake breakout lahar: Insights into flow dynamics and the implications on mass flow monitoring

    NASA Astrophysics Data System (ADS)

    Walsh, B.; Jolly, A. D.; Procter, J. N.

    2016-09-01

    On 6 August 2012 an eruption of the upper Te Maari vent Tongariro volcano and subsequent debris flow in the Mangatetipua channel created a debris dam and ephemeral lake. The lake reached its maximum volume of 50,000 m3 by 13 October, initiating dam breaching at 22:30 NZDT (11:30 UTC) after a period of intense rainfall. The breach eventually grew to 29 × 12 m, causing eroded debris flow sediment and water to remobilize as a lahar. The event, comprising multiple surges, lasted ~ 30 min, and displaced 57,000 m3 of remobilized sediment up to 4.5 km downstream. To determine the dynamics of the event, the seismic signals generated by the lahar were compared with active seismic source data collected in February 2013. The comparison used a common frequency band range of 3-10 Hz to compute amplitude for four near-field seismic stations. For periods with signal-to-noise ratios above 2.0, we obtained lahar amplitude distributions that match best the equivalent active source amplitudes within ~ 0.5 km of the dam breakout. The accumulated seismic energy of the lahar was estimated at 1.93 × 109 Nm, whereas the peak energy was 6.88 × 107 Nm. Results of this work may improve the characterization of future mass flow events in the Te Maari/Mangatetipua area through the calibration of seismic stations used in this study.

  2. Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO2 Enhanced Oil Recovery Operations

    SciTech Connect

    Brian E. Toelle

    2006-02-28

    The ''Application of Time-Lapse Seismic Monitoring for the Control and Optimization of CO{sub 2} Enhanced Oil Recovery Operations'' project is investigating the potential for monitoring CO{sub 2} floods in carbonate reservoirs through the use of standard p-wave seismic data. This project will involve the use of 4D seismic (time lapse seismic) to try to observe the movement of the injected CO{sub 2} through the reservoir. The differences between certain seismic attributes, such as amplitude, will be used to detect and map the movement of CO{sub 2} within the reservoir. This technique has recently been shown to be effective in CO{sub 2} monitoring in EOR projects such as Weyborne. The project is being conducted in the Charlton 30/31 field in northern Michigan Basin which is a Silurian pinnacle reef that has completed its primary production. This field is now undergoing enhanced oil recovery using CO{sub 2}. The CO{sub 2} flood was initiated the end of 2005 when the injection of small amounts of CO{sub 2} begin in the A1 Carbonate. This injection was conducted for 2 months before being temporarily halted in order for pressure measurements to be conducted. The determination of the reservoir's porosity distribution is proving to be a significant portion of this project. In order to relate the differences observed between the seismic attributes seen on the multiple surveys and the actual location of the CO{sub 2}, a predictive reservoir simulation model had to be developed. From this model, an accurate determination of porosity within the carbonate reservoir must be obtained. For this certain seismic attributes have been investigated. The study reservoirs in the Charlton 30/31 field range from 50 to 400 acres in size. The relatively small area to image makes 3-D seismic data acquisition reasonably cost effective. Permeability and porosity vary considerably throughout the reef, thus it is essential to perform significant reservoir characterization and modeling prior to

  3. Development of Rapid Seismic Monitoring Procedures for Incorporation into the Caribbean Tsunami Warning System

    NASA Astrophysics Data System (ADS)

    Huerfano, V. A.; von Hillebrandt, C. G.; Mendoza, C.

    2007-05-01

    "Middle America", the geographic area between North and South America, including the Caribbean, has been a site of great plate tectonic activity in the most recent 35 million years. The region continues to be highly geologically active today as the Caribbean tectonic plate advances to the east, interacting with the North American and South American plates. Type examples of many of the salient features of plate tectonics-subduction zones, deep trenches, transform faults, pull-apart basins, subduction-to-strike-slip transitions, subduction-related volcanism, and volcano-free subduction zones-exist in a relatively small geographical area. The circum-Caribbean region has a documented history of destructive earthquakes and large damaging tsunamis that have affected coastal areas, including the events of Virgin Islands in 1867 and Mona Passage in 1918. These tsunamis have been triggered by large earthquakes that deformed the ocean floor. Tsunami waves originating in the prominent fault system around the Caribbean are considered to pose a near-field hazard because they can reach populated coastal areas within a few minutes after the earthquake. Because of this situation, the need to establish a system of rapid notification for tsunami alerting in the Caribbean has been recognized by emergency management agencies and the scientific community. In the wake of the December 26, 2004 devastating earthquake and tsunami in Indonesia, attention has been focused worldwide on the establishment of local and regional tsunami warning systems. The objective of the monitoring component of the Caribbean tsunami warning system under development in the Puerto Rico Seismic Network since 2000 is to detect, inform and confirm as rapidly and accurately as possible potential tsunamigenic events. In this presentation, we will describe the application of waveform analysis procedures for the rapid identification of shallow earthquake source parameters (geometry and size) in the Caribbean using

  4. Seismic intrusion detector system

    DOEpatents

    Hawk, Hervey L.; Hawley, James G.; Portlock, John M.; Scheibner, James E.

    1976-01-01

    A system for monitoring man-associated seismic movements within a control area including a geophone for generating an electrical signal in response to seismic movement, a bandpass amplifier and threshold detector for eliminating unwanted signals, pulse counting system for counting and storing the number of seismic movements within the area, and a monitoring system operable on command having a variable frequency oscillator generating an audio frequency signal proportional to the number of said seismic movements.

  5. Comprehensive Seismic Monitoring for Emergency Response and Hazards Assessment: Recent Developments at the USGS National Earthquake Information Center

    NASA Astrophysics Data System (ADS)

    Buland, R. P.; Guy, M.; Kragness, D.; Patton, J.; Erickson, B.; Morrison, M.; Bryon, C.; Ketchum, D.; Benz, H.

    2009-12-01

    The USGS National Earthquake Information Center (NEIC) has put into operation a new generation of seismic acquisition, processing and distribution subsystems that seamlessly integrate regional, national and global seismic network data for routine monitoring of earthquake activity and response to large, damaging earthquakes. The system, Bulletin Hydra, was designed to meet Advanced National Seismic System (ANSS) design goals to handle thousands of channels of real-time seismic data, compute and distribute time-critical seismic information for emergency response applications, and manage the integration of contributed earthquake products and information, arriving from near-real-time up to six weeks after an event. Bulletin Hydra is able meet these goals due to a modular, scalable, and flexible architecture that supports on-the-fly consumption of new data, readily allows for the addition of new scientific processing modules, and provides distributed client workflow management displays. Through the Edge subsystem, Bulletin Hydra accepts waveforms in half a dozen formats. In addition, Bulletin Hydra accepts contributed seismic information including hypocenters, magnitudes, moment tensors, unassociated and associated picks, and amplitudes in a variety of formats including earthworm import/export pairs and EIDS. Bulletin Hydra has state-driven algorithms for computing all IASPEI standard magnitudes (e.g. mb, mb_BB, ML, mb_LG, Ms_20, and Ms_BB) as well as Md, Ms(VMAX), moment tensor algorithms for modeling different portions of the wave-field at different distances (e.g. teleseismic body-wave, centroid, and regional moment tensors), and broadband depth. All contributed and derived data are centrally managed in an Oracle database. To improve on single station observations, Bulletin Hydra also does continuous real-time beam forming of high-frequency arrays. Finally, workflow management displays are used to assist NEIC analysts in their day-to-day duties. All combined

  6. Testing the ability of different seismic detections approaches to monitor aftershocks following a moderate magnitude event.

    NASA Astrophysics Data System (ADS)

    Romero, Paula; Díaz, Jordi; Ruiz, Mario; Cantavella, Juan Vicente; Gomez-García, Clara

    2016-04-01

    The detection and picking of seismic events is a permanent concern for seismic surveying, in particular when dealing with aftershocks of moderate magnitude events. Many efforts have been done to find the balance between computer efficiency and the robustness of the detection methods. In this work, data recorded by a high density seismic network deployed following a 5.2 magnitude event located close to Albacete, SE Spain, is used to test the ability of classical and recently proposed detection methodologies. Two days after the main shock, occurred the 23th February, a network formed by 11 stations from ICTJA-CSIC and 2 stations from IGN were deployed over the region, with inter-station distances ranging between 5 and 10 km. The network remained in operation until April 6th, 2015 and allowed to manually identify up to 552 events with magnitudes from 0.2 to 3.5 located in an area of just 25 km2 inside the network limits. The detection methods here studied applied are the classical STA/LTA, a power spectral method, a detector based in the Benford's law and a waveform similarity method. The STA/LTA method, based in the comparison of background noise and seismic signal amplitudes, is taken as a reference to evaluate the results arising from the other approaches. The power spectral density method is based in the inspection of the characteristic frequency pattern associated to seismic events. The Benford's Law detector analyses the distribution of the first-digit of displacement count in the histogram of a seismic waveform, considering that only the windows containing seismic wave arrivals will match the logarithmic law. Finally, the waveform similarity method is based in the analysis of the normalized waveform amplitude, detecting those events with waveform similar to a previously defined master event. The aim of this contribution is to inspect the ability of the different approaches to accurately detect the aftershocks events for this kind of seismic crisis and to

  7. A plan of continuous monitoring of seismic signature at the top of the subducting Philippine Sea Plate using the ACROSS active monitoring method

    NASA Astrophysics Data System (ADS)

    Kasahara, J.; Tsuruga, K.; Hasada, Y.; Yamaoka, K.; Kunitomo, T.; Watanabe, T.; Fujii, N.; Yoshida, Y.; Kumazawa, M.

    2004-12-01

    Recently, a very strong reflected PP phase from the subducting plate boundary was found beneath the aseismic forearc slope of the Japan Trench (Fujie et al., 2003, Kasahara et al., 2003). This strong PP reflection is interpreted as a reflection from the non-asperity region along the plate boundary caused by the presence of low-Vp material. Similar strong PP reflection phase was observed near the plate boundary of the subducting Philippine Sea Plate and the Eurasian Plate, in the western part of Shizuoka Prefecture along the NS seismic survey line across the central part of Japan using explosive sources (Iidaka et al., 2003, Kodaira et al., 2004). This region is match to the aseismic slip zone since 2000 observed by GPS (Ozawa et al., 2002). This region is supposed to the lower edge of future Tokai or Tonankai earthquake along the Nankai Trough. The "ACROSS" (Accurately Controlled and Routinely Operated Signal System) (Kunitomo and Kumazawa, 2004) can continuously transmit accurately-controlled seismic waves in amplitude, frequency and phase. Using continuous transmission of seismic waves from the ACROSS source located in Toki City, Japan and /or the new ACROSS source under planning in the western part of Shizuoka Prefecture and the high sensitivity seismometers along the NS traverse line, we can delineate the temporal variation of seismic wave properties of the anomalously reflected PP phase along the boundary of subducting Philippine Sea Plate. This observation can give information on variation of the physical state of frictional slip and clues for the earthquake generation. It is also very useful for the monitoring of precursory slip and/or after-slip of the future Tokai and Tonankai earthquakes (or any large earthquakes) with sources along the Philippine Sea Plate.

  8. Monitoring seismic and silent faulting along the Atacama Fault System and its relation to the subduction zone seismic cycle: A Creepmeter Study in N-CHile

    NASA Astrophysics Data System (ADS)

    Victor, Pia; Ziegenhagen, Thomas; Bach, Christoph; Walter, Thomas; Oncken, Onno

    2010-05-01

    The relationship between crustal forearc faults and subduction zone processes is little understood and therefore the modern seismogenic capacity of these faults cannot be determined. The Atacama Fault System (AFS) is the dominant trench parallel fault in N-Chile with an along strike extent of 1000km. In order to characterize the mode of deformation accumulation and its spatio-temporal distribution, we are continuously monitoring displacement accumulation along active fault branches with a recently installed Creepmeter array. All the installed Creepmeters use 12 mm thick Invar-rod as length standard buried up to 0.7 m depth to reduce the signal to noise ratio, and measure the length standard change across a fault on outcrop scale. The currently deployed 9 sites are designed for displacement detection in the range of 0.001 - 50 mm/yr with a sampling rate of 1/min. The monitored fault branches have been chosen such that 3 Creepmeter sites are located in the Iquique seismic gap of the subduction zone, 5 instruments are located in the segment that recently ruptured in the 2007 Tocopilla earthquake, whereof 2 are located on the Mejillones Peninsula and one is located in the Antofagasta segment that last ruptured in the 1995 Antofagasta Earthquake. This enables us to compare the mode of strain accumulation in different stages of the subduction zone seismic cycle. The first datasets (> 1 yr) show that the instruments both in the Antofagasta and Tocopilla segments display a continuous creep signal equivalent to extensional displacement across the fault zone superimposed by sudden displacement events related to subduction zone earthquakes. The sum of both amounts to 0.02 mm/y - 0.1 mm/y of displacement which is less than predicted by the geological long-term observation. The data from the Chomache Fault located in the Iquique segment shows only a creep signal for the first year after installation with an average extensional displacement rate of 0.05 mm/y. No sudden

  9. Improved sea level monitors for measuring vertical crustal deformation in the Shumagin seismic gap, Alaska

    NASA Technical Reports Server (NTRS)

    Hurst, Ken; Beavan, John

    1987-01-01

    The relative vertical deformation detection capability of a network of sea level gauges in the Shumagin seismic gap, Alaska has been improved. An examination of the present noise levels suggests that the network is now capable of providing relative deformation data that is quieter than data from leveling, GPS, VLBI, or satellite laser ranging.

  10. The Complementary Nature of Seismic and Infrasound Technologies in Regional Monitoring (Invited)

    NASA Astrophysics Data System (ADS)

    Stump, B. W.; Hayward, C.; Park, J.

    2013-12-01

    Under current CTBTO event detection and location operating conditions, signal detection is a station-centric decision (was an event phase detected at this station?), rather than a global hypothesis test. Currently, infrasound and seismic detection use signal detectors run independently on each technology. It is only after event formation that the observations and inferences are merged. Development of this independent processing is a result of the vastly different signal and noise characteristics of these two waveform technologies. However, for specific signals there may be a utility to a joint seismic-infrasound detector. For example, noise estimates from one technology may help characterize or identify the noise on another technology (wind couples to both infrasound and seismic). Back-projection methods for both seismic and infrasound could easily be combined to produce a common seismo-acoustic detection and associated event location. The opportunity exists to integrate detection and location into a single multi-disciplinary approach. One such example is the ongoing infrasound detection and location procedure that utilizes an adaptive F-detector as input into the Bayesian Infrasonic Source Location (BISL, Modrak et al. 2010) procedure that provides an estimate of source location using assigned prior probabilities based on what is known of the propagation path and on the signal detector estimates (arrival time, phase velocity and azimuth). As the atmospheric model is better defined these priors may be changed, thus linking improved location estimates directly to improvements in atmospheric models. The final step following event location is identification. Seismic and infrasound observations and their interpretation for the recent set of North Korean nuclear explosions in 2006, 2009, and 2013 provide a motivation for multiple disciplinary approach to this step as well. Seismic analysis of these tests have documented that for existing parameterized source models

  11. The Complementary Nature of Seismic and Infrasound Technologies in Regional Monitoring (Invited)

    NASA Astrophysics Data System (ADS)

    Shi, Y.; Gao, Y.; Liu, K. H.; Gao, S. S.

    2011-12-01

    Under current CTBTO event detection and location operating conditions, signal detection is a station-centric decision (was an event phase detected at this station?), rather than a global hypothesis test. Currently, infrasound and seismic detection use signal detectors run independently on each technology. It is only after event formation that the observations and inferences are merged. Development of this independent processing is a result of the vastly different signal and noise characteristics of these two waveform technologies. However, for specific signals there may be a utility to a joint seismic-infrasound detector. For example, noise estimates from one technology may help characterize or identify the noise on another technology (wind couples to both infrasound and seismic). Back-projection methods for both seismic and infrasound could easily be combined to produce a common seismo-acoustic detection and associated event location. The opportunity exists to integrate detection and location into a single multi-disciplinary approach. One such example is the ongoing infrasound detection and location procedure that utilizes an adaptive F-detector as input into the Bayesian Infrasonic Source Location (BISL, Modrak et al. 2010) procedure that provides an estimate of source location using assigned prior probabilities based on what is known of the propagation path and on the signal detector estimates (arrival time, phase velocity and azimuth). As the atmospheric model is better defined these priors may be changed, thus linking improved location estimates directly to improvements in atmospheric models. The final step following event location is identification. Seismic and infrasound observations and their interpretation for the recent set of North Korean nuclear explosions in 2006, 2009, and 2013 provide a motivation for multiple disciplinary approach to this step as well. Seismic analysis of these tests have documented that for existing parameterized source models

  12. Seismic Monitoring Capabilities of the Caribbean and Adjacent Regions Tsunami Warning System

    NASA Astrophysics Data System (ADS)

    Saurel, Jean-Marie; von Hillebrandt-Andrade, Christa; Crespo, Hector; McNamara, Dan; Huerfano, Victor

    2014-05-01

    Over 75 tsunamis have been documented in the Caribbean and Adjacent Regions during the past 500 years. Since 1500, at least 4484 people are reported to have perished in these killer waves. Hundreds of thousands are currently threatened along the Caribbean coastlines. In 2005 the Intergovernmental Coordination Group for the Tsunami and other Coastal Hazards Warning System for the Caribbean and Adjacent Regions (CARIBE EWS) was established. It recommended the following minimum seismic performance standards for the detection and analysis of earthquakes: 1) Earthquake detection within 1 minute, 2) Minimum magnitude threshold = M4.5, and 3) Initial hypocenter error of <30 km. The implementation plan of the CARIBE EWS currently includes 115 seismic stations in the Caribbean and Adjacent Regions. The NOAA National Weather Service Caribbean Tsunami Warning Program prepares and distributes monthly reports on real time and archived seismic data availability of the contributing stations at the US Tsunami Warning Centers, the Puerto Rico Seismic Network and IRIS. As of early 2014, 99 of the proposed stations are being contributed by national, regional and international seismological institutions. Recent network additions (Nicaragua, Colombia, Mexico, Cayman Islands, and Venezuela) have reduced detection threshold, time and location error throughout much of the Caribbean region and Central America. Specifically, earthquakes (>M4.0) can be detected within 1 minute throughout much of the Caribbean. The remaining exceptions to this standard for detection are portions of northern South America and Mexico. Another performance criterion is 90% data availability. Currently 60-70% of the stations meet this standard. The presentation will further report on the status of the CARIBE EWS seismic capability for the timely and accurate detection and analysis of earthquakes for tsunami warning purposes for the Caribbean and Adjacent Regions.

  13. Modeling the resolution of inexpensive, novel non-seismic geophysical monitoring tools to monitor CO2 injection into coal beds

    SciTech Connect

    Gasperikova, E.; Hoversten, G.M.

    2008-09-01

    A sensitivity study of gravity and electromagnetic (EM) techniques, and amplitude vs. angle (AVA) analysis for CO{sub 2} movement in coal beds was based on the SECARB pilot test planned in the Black Warrior basin in Alabama. In the area of interest, coalbed methane is produced mainly from the Black Creek, Mary Lee, and Pratt coal zones at depths between 400 and 700 m and approximately 3 m thick on average. The permeability of coal in the Black Warrior basin decreases exponentially with depth as overburden stress increases. The permeability of the top layer is 100 mD, while the permeability of the deepest layer is around 1 mD. The pilot field test will include injecting a total of 1000 tons of CO{sub 2} into these three coal zones ({approx}300 tons to each zone). The density, sonic and resistivity well-logs from a deep disposal well a couple of miles from the pilot test site were used to create background (pre-injection) models. Our laboratory measurements of seismic velocity and electrical resistivity as a function of CO{sub 2} saturation on coal core samples were used to provide a link between the coalbed CO{sub 2} flow simulation models and the geophysical models. The sensitivity studies showed that while the response to the 300 tons of CO{sub 2} injected into a single layer wouldn't produce measurable surface response for either gravity or EM, the response due to an industrial-size injection would produce measurable surface signal for both techniques. Gravity inversion results illustrated that, provided we can collect high-quality gravity data in the field and we have some a priori information about the depth of the reservoir, we can recover the spatial location of CO{sub 2} plume correctly, although with the smoothing constraint of the inversion, the area was slightly overestimated, resulting in an underestimated value of density change. AVA analysis showed that by inverting seismic and EM data jointly, much better estimates of CO{sub 2} saturation can be

  14. A Dynamic Programming Model for Optimizing Frequency of Time-Lapse Seismic Monitoring in Geological CO2 Storage

    NASA Astrophysics Data System (ADS)

    Bhattacharjya, D.; Mukerji, T.; Mascarenhas, O.; Weyant, J.

    2005-12-01

    Designing a cost-effective and reliable monitoring program is crucial to the success of any geological CO2 storage project. Effective design entails determining both, the optimal measurement modality, as well as the frequency of monitoring the site. Time-lapse seismic provides the best spatial coverage and resolution for reservoir monitoring. Initial results from Sleipner (Norway) have demonstrated effective monitoring of CO2 plume movement. However, time-lapse seismic is an expensive monitoring technique especially over the long term life of a storage project and should be used judiciously. We present a mathematical model based on dynamic programming that can be used to estimate site-specific optimal frequency of time-lapse surveys. The dynamics of the CO2 sequestration process are simplified and modeled as a four state Markov process with transition probabilities. The states are M: injected CO2 safely migrating within the target zone; L: leakage from the target zone to the adjacent geosphere; R: safe migration after recovery from leakage state; and S: seepage from geosphere to the biosphere. The states are observed only when a monitoring survey is performed. We assume that the system may go to state S only from state L. We also assume that once observed to be in state L, remedial measures are always taken to bring it back to state R. Remediation benefits are captured by calculating the expected penalty if CO2 seeped into the biosphere. There is a trade-off between the conflicting objectives of minimum discounted costs of performing the next time-lapse survey and minimum risk of seepage and its associated costly consequences. A survey performed earlier would spot the leakage earlier. Remediation methods would have been utilized earlier, resulting in savings in costs attributed to excessive seepage. On the other hand, there are also costs for the survey and remedial measures. The problem is solved numerically using Bellman's optimality principal of dynamic

  15. INL Seismic Monitoring Annual Report: January 1, 2009 – December 31, 2009

    SciTech Connect

    N. S. Carpenter; S. J. Payne; J. M. Hodges; R. G. Berg

    2010-09-01

    The Idaho National Laboratory (INL) has accumulated 37 years of earthquake data (1972-2009). This report covers the earthquake activity from January 1, 2009 through December 31, 2009 and is a continuation of previous annual reports on earthquake activity surrounding the eastern Snake River Plain (ESRP) and within and near the INL. It discusses the earthquake activity that has occurred around the local region and within a 161-km radius around the INL centered at 43? 39.00' N, 112? 47.00' W). It discusses the seismic station and strong motion accelerograph instrumentation used to record earthquake data and how they were analyzed. It also includes a brief discussion of continuous GPS (Global Positioning System) stations co-located at INL seismic stations.

  16. Time-lapse Monitoring of Geotechnical Properties of Heritage Earthworks by Means of Near-Surface Seismic Techniques

    NASA Astrophysics Data System (ADS)

    Bergamo, P.; Donohue, S.; Gunn, D.; Dashwood, B.

    2014-12-01

    Surface wave (SW) method and P-wave refraction tomography are widely spread methods for the characterization of the near-surface. We applied these techniques to a 1-year time-lapse monitoring of the geotechnical properties of a heritage earthwork at risk of failure, a stretch of the embankment of the Gloucestershire-Warwickshire railway in Laverton, UK. Like a significant part of UK railway network, this line was built in the early 20th century without modern construction standards. Poor maintenance and the increase in extreme weather events due to recent climate change have further compromised its stability. The aim of this monitoring campaign is to assess the capability of non-invasive and repeatable geophysical methods to measure temporal changes of mechanical parameters of earthworks. MASW (multichannel analysis of SW) and P-wave refraction data were repeatedly acquired along a 100 m line on the crest of the embankment, every other month from July 2013 to July 2014. Smaller scale seismic data were also recorded on the flanks of the embankment. Sensors measuring climate -temperature, precipitation, solar radiation - and geotechnical parameters - water content, suction - were installed at various locations and depths within the embankment. Moreover, penetrometric data were acquired, soil samples were analysed. SW data were analysed in terms of phase velocity and attenuation. Hodocrones, dispersion and attenuation curves show a limited but continuous seasonal change. SW dispersion curves and P-wave travel times were separately inverted for VS and VP models with a laterally constrained and a tomographic approach, respectively. The VS and VP sections describe the temporal variation of seismic properties of the embankment, consistent with the climate trend. Such results were jointly interpreted with data from field sensors and cone penetration testing. This calibration stage provides a geotechnical model that explains the temporal variations of seismic velocities

  17. Towards a Comprehensive Seismic Velocity Model for the Broader Africa-Eurasia Collision Region, to Improve Nuclear Explosion Monitoring

    SciTech Connect

    der Lee, S v; Flanagan, M P; Rodgers, A J; Pasyanos, M E; Marone, F; Romanowicz, B

    2005-07-13

    We report on progress towards a new, comprehensive three-dimensional model of seismic velocity in a broad region encompassing the Middle East, northern Africa, the Mediterranean Sea, the Levant, the Arabian Peninsula, the Turkish-Iranian Plateau, Indus Valley, and the Hindu Kush. Our model will be based on regional waveform fits, surface wave group velocity measurements, teleseismic arrival times of S and P waves, receiver functions, and published results from active source experiments. We are in the process of assembling each of these data sets and testing the joint inversion for subsets of the data. Seismograms come from a variety of permanent and temporary seismic stations in the region. Some of the data is easily accessible through, for example, IRIS, while collection of other data is more involved. This work builds on ongoing work by Schmid et al. (GJI, 2004, and manuscript in preparation). In these proceedings we highlight our data sets and their inferences, demonstrate the proposed new data-inversion modeling methodology, discuss results from preliminary inversions of subsets of the data, and demonstrate the prediction of arrival times with three-dimensional velocity models. We compare our preliminary inversion results to the results of Schmid et al., and the predicted arrival times to ground-truth data from the NNSA Knowledge Base. Our data sets are simultaneously redundant and highly complementary. The combined data coverage will ensure that our three-dimensional model comprises the crust, the upper mantle, including the transition zone, and the top of the lower mantle, with spatially varying, but useful resolution. The region of interest is one of the most structurally heterogeneous in the world. Continental collision, rifting and sea-floor spreading, back-arc spreading, oceanic subduction, rotating micro plates, continental shelf, and stable platforms, are just some of the region's characteristics. Seismicity and the distribution of seismic stations are

  18. Monitoring Rotational Components of Seismic Waves with a Ring Laser Interferometer

    NASA Astrophysics Data System (ADS)

    Gakundi, Jackson; Dunn, Robert

    2015-04-01

    It has been known for decades that seismic waves can introduce rotation in the surface of the Earth. There are historic records of tombstones in Japan being rotated after large earthquakes. Until fairly recently, the primary way to detect ground rotation from earthquakes was with an array of several seismographs. The development of large ring laser interferometers has provided a way for a single instrument to make extremely sensitive measurements of ground motion. In this poster, a diagram of a large ring laser will be presented. For comparison, seismograms recorded with a ring laser and a collocated standard seismograph will be presented. A major thrust of this research is the detection and analysis of seismic responses from directional drilling sites in Arkansas and Oklahoma. There are suggestions that the injection of pressurized water used to fracture gas bearing shale may cause small earthquakes. The Arkansas Oil and Gas Commission ordered the closing of certain waste water disposal wells in North Central Arkansas. Apparently, these wells injected waste water into a previously unknown fault causing it to slip. An attempt is being made to determine if the seismic wave patterns from earthquakes generated near directional drilling sites differ from those generated miles away.

  19. A qualitative study of seismic-ionospheric precursor phenomena monitored by a very close to the epicenter VLF and LF receiver

    NASA Astrophysics Data System (ADS)

    Skeberis, C.; Zaharis, Z. D.; Xenos, T. D.; Spatalas, S.; Contadakis, M. E.

    2015-12-01

    This work investigates the occurrence of disturbances across a wide range of VLF and LF frequencies received prior to a seismic event (Mw = 4), that took place on May 12th 2012, the epicenter of which was very close (14 km) to the VLF/LF station. The signals analyzed were emitted from five VLF and five LF European transmitters. This seismic event produced precursory ionospheric disturbances, identified as spectral distortion, three days before its occurrence, providing a distinct pattern open to further investigation. Although the basis of the ionosphere interaction with seismic phenomena has been well documented in previous studies, the close proximity of the receiver to the seismic event provides a new perspective to this study. The monitored signals have undergone normalization and then they have been processed by means of the Hilbert-Huang Transform. Diagrams of the signals relevant to the phenomena are presented and the disturbances that are present in the raw data are accentuated through further processing.

  20. Time-lapse CO2 monitoring using ambient-noise seismic interferometry: a feasibility study from Ketzin, Germany

    NASA Astrophysics Data System (ADS)

    Boullenger, Boris; Verdel, Arie; Paap, Bob; Thorbecke, Jan; Draganov, Deyan

    2015-04-01

    necessarily exclude acceptable time-lapse signal retrieval. Furthermore, the clarity of the time-lapse signal at the reservoir level increases with increasing repeatability of the two passive experiments. The increase in repeatability is achieved when the contributing noise sources form denser clusters that share analogous spatial coverage. To support the merits of the numerical experiments, we applied ANSI (by auto-correlation) to three days of Ketzin passive field-data and compare the retrieved responses with the modelling results. The data are recorded at a permanent array of sensors (hydrophones and geophones) installed above the injection site. We used the records from the buried line of the array that consists of sensors lying at 50-meters depth. These records are less contaminated with surface noise and preserve passive body-wave events better than surface-recorded data. The retrieved responses exhibit significant correspondence with the existing active-seismic field data as well as with our modelled ANSI and active responses. Key reflection events seem to be retrieved at the expected arrival times and support the idea that the settings and characteristics of the ambient noise at Ketzin offer good potential for time-lapse ANSI to monitor CO2 sequestration.

  1. Using Seismic Noise Generated by Ocean Waves to Monitor Seasonal and Secular Changes in Antarctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Anthony, R. E.; Aster, R. C.; Thompson, D. W. J.; Reusch, D. B.

    2015-12-01

    The Earth's background seismic noise between ~1-30 seconds period is commonly dominated by microseisms that arise when oceanic wave energy and swell are converted to ground displacement as the waves crash and interact with the continental shelf. Peak power in the microseism bands at high-latitude stations typically coincides with large-scale extratropical cyclonic winter storm activity. However, due to the seasonal formation of sea ice around the continental shelves of polar regions, oceanic waves are impeded from efficiently exciting seismic energy, and annual peak microseism power thus occurs prior to the midwinter storm peak. We utilize recently collected seismic data from across the continent to show that power in three distinct microseism bands is found to be strongly anti-correlated with sea ice extent, with the shorter period signals being exceptionally sensitive to local conditions. Particular focus is given to the Antarctic Peninsula, the strongest source of microseism energy on the continent, where we note a significant increase in primary microseism power attributable to near coastal sources from 1993-2012. This increase correlates with regional sea ice loss driven by large-scale wind changes associated with strengthening of the Southern Annular Mode. Additionally, we use microseism analysis to explore changes in sea ice strength and extent relative to wave state and storminess in the Southern Oceans. Investigation of microseism seasonality, power, and decadal-scale trends in the Antarctic shows promise as a spatially integrated tool for monitoring and interpreting such sea ice strength and extent metrics through time.

  2. The community seismic network and quake-catcher network: enabling structural health monitoring through instrumentation by community participants

    NASA Astrophysics Data System (ADS)

    Kohler, Monica D.; Heaton, Thomas H.; Cheng, Ming-Hei

    2013-04-01

    A new type of seismic network is in development that takes advantage of community volunteers to install low-cost accelerometers in houses and buildings. The Community Seismic Network and Quake-Catcher Network are examples of this, in which observational-based structural monitoring is carried out using records from one to tens of stations in a single building. We have deployed about one hundred accelerometers in a number of buildings ranging between five and 23 stories in the Los Angeles region. In addition to a USB-connected device which connects to the host's computer, we have developed a stand-alone sensor-plug-computer device that directly connects to the internet via Ethernet or wifi. In the case of the Community Seismic Network, the sensors report both continuous data and anomalies in local acceleration to a cloud computing service consisting of data centers geographically distributed across the continent. Visualization models of the instrumented buildings' dynamic linear response have been constructed using Google SketchUp and an associated plug-in to matlab with recorded shaking data. When data are available from only one to a very limited number of accelerometers in high rises, the buildings are represented as simple shear beam or prismatic Timoshenko beam models with soil-structure interaction. Small-magnitude earthquake records are used to identify the first set of horizontal vibrational frequencies. These frequencies are then used to compute the response on every floor of the building, constrained by the observed data. These tools are resulting in networking standards that will enable data sharing among entire communities, facility managers, and emergency response groups.

  3. Active Seismic Monitoring Using High-Power Moveable 40-TONS Vibration Sources in Altay-Sayn Region of Russia

    NASA Astrophysics Data System (ADS)

    Soloviev, V. M.; Seleznev, V. S.; Emanov, A. F.; Kashun, V. N.; Elagin, S. A.; Romanenko, I.; Shenmayer, A. E.; Serezhnikov, N.

    2013-05-01

    The paper presents data of operating vibroseismic observations using high-power stationary 100-tons and moveable 40-tons vibration sources, which have been carried out in Russia for 30 years. It is shown that investigations using high-power vibration sources open new possibilities for study stressedly-deformed condition of the Earth`s crust and the upper mantle and tectonic process in them. Special attention is given to developing operating seismic translucences of the Earth`s crust and the upper mantle using high-power 40-tons vibration sources. As a result of experimental researches there was proved high stability and repeatability of vibration effects. There were carried out long period experiments of many days with vibration source sessions of every two hours with the purpose of monitoring accuracy estimation. It was determined, that repeatability of vibroseismic effects (there was researched time difference of repeated sessions of P- and S-waves from crystal rocks surface) could be estimated as 10-3 - 10-4 sec. It is ten times less than revealed here annual variations of kinematic parameters according to regime vibroseismic observations. It is shown, that on hard high-speed grounds radiation spectrum becomes narrowband and is dislocated to high frequency; at the same time quantity of multiple high-frequency harmonic is growing. At radiation on soft sedimentary grounds (sand, clay) spectrum of vibration source in near zone is more broadband, correlograms are more compact. there Correspondence of wave fields from 40-tons vibration sources and explosions by reference waves from boundaries in he Earth`s crust and the upper mantle at record distance of 400 km was proved by many experiments in various regions of Russia; there was carried out the technique of high-power vibration sources grouping for increase of effectiveness of emanation and increase of record distance. According to results of long-term vibroseismic monitoring near Novosibirsk (1997-2012) there are

  4. Active seismic experiment

    NASA Technical Reports Server (NTRS)

    Kovach, R. L.; Watkins, J. S.; Talwani, P.

    1972-01-01

    The Apollo 16 active seismic experiment (ASE) was designed to generate and monitor seismic waves for the study of the lunar near-surface structure. Several seismic energy sources are used: an astronaut-activated thumper device, a mortar package that contains rocket-launched grenades, and the impulse produced by the lunar module ascent. Analysis of some seismic signals recorded by the ASE has provided data concerning the near-surface structure at the Descartes landing site. Two compressional seismic velocities have so far been recognized in the seismic data. The deployment of the ASE is described, and the significant results obtained are discussed.

  5. Extending the life of mature basins in the North Sea and imaging sub-basalt and sub-intrusive structures using seismic intensity monitoring.

    NASA Astrophysics Data System (ADS)

    De Siena, Luca; Rawlinson, Nicholas

    2016-04-01

    Non-standard seismic imaging (velocity, attenuation, and scattering tomography) of the North Sea basins by using unexploited seismic intensities from previous passive and active surveys are key for better imaging and monitoring fluid under the subsurface. These intensities provide unique solutions to the problem of locating/tracking gas/fluid movements in the crust and depicting sub-basalt and sub-intrusives in volcanic reservoirs. The proposed techniques have been tested in volcanic Islands (Deception Island) and have been proved effective at monitoring fracture opening, imaging buried fluid-filled bodies, and tracking water/gas interfaces. These novel seismic attributes are modelled in space and time and connected with the lithology of the sampled medium, specifically density and permeability with as key output a novel computational code with strong commercial potential.

  6. INL Seismic Monitoring Annual Report: January 1, 2005 - December 31, 2005

    SciTech Connect

    S. J. Payne; A. A. Holland; J. M. Hodges; R. G. Berg

    2006-09-01

    During 2005, the Idaho National Laboratory (INL) recorded 2390 independent triggers from earthquakes both within the region and from around the world. 38 small to moderate size earthquakes ranging in magnitude from 3.0 to 5.7 occurred within and outside the 161-km (100-mile) radius of INL. Earthquakes activity occurred in areas that have experienced seismic activity in the past, the Basin and Range northwest of the INL, southwestern Montana, Yellowstone Park, Wyoming, Jackson, Wyoming, and southeastern Idaho. INL recorded the July 26, 2005 body-wave magnitude (mb) 5.7 Dillon, Montana earthquake and 100’s of associated aftershocks. Local residents felt the earthquake and experienced minor damage. The mb 5.7 main shock was located more than 170 km (105 miles) from INL facilities and was not felt. The main shock did not trigger any strong-motion accelerographs (SMAs) located within INL buildings. Free-field SMAs and accelerometers co-located with seismic stations recorded acceleration data. Peak horizontal and vertical accelerations range from 0.0077 to 0.0006 g. There were 449 earthquakes with magnitudes up to 4.6 that occurred within the 161-km radius of the INL in the Basin and Range surrounding the eastern Snake River Plain (ESRP). No earthquakes occurred within the INL boundaries or the ESRP. The largest earthquake occurred on October 31, 2005 and had a moment magnitude (Mw) 4.6. It was located north of Leadore, Idaho at a distance of 100 km (62 miles) from INL. The earthquake did not trigger SMAs located within INL buildings. Free-field SMAs and accelerometers co-located at seismic stations recorded peak horizontal and vertical accelerations that ranged from 0.0003 to 0.0030 g.

  7. Seismic velocity changes associated with aseismic deformations of a fault stimulated by fluid injection

    NASA Astrophysics Data System (ADS)

    Rivet, Diane; De Barros, Louis; Guglielmi, Yves; Cappa, Frédéric; Castilla, Raymi; Henry, Pierre

    2016-09-01

    Fluid pressure plays an important role in the stability of tectonic faults. However, the in situ mechanical response of faults to fluid pressure variations is still poorly known. To address this question, we performed a fluid injection experiment in a fault zone in shales while monitoring fault movements at the injection source and seismic velocity variations from a near-distance (<10 m) monitoring network. We measured and located the P and S wave velocity perturbations in and around the fault using repetitive active sources. We observed that seismic velocity perturbations dramatically increase above 1.5 MPa of injection pressure. This is consistent with an increase of fluid flow associated with an aseismic dilatant shearing of the fault as shown by numerical modeling. We find that seismic velocity changes are sensitive to both fault opening by fluid invasion and effective stress variations and can be an efficient measurement for monitoring fluid-driven aseismic deformations of faults.

  8. Acoustic monitoring of co-seismic changes in gas bubble rupture rate in a hydrothermal reservoir: field evaluation of a possible precursor and mechanism for remote seismic triggering

    NASA Astrophysics Data System (ADS)

    Crews, J. B.

    2015-12-01

    Remotely triggered seismicity is a phenomenon in which an earthquake at one location triggers others over distances up to thousands of kilometers. The mechanism by which low-amplitude dynamic oscillations of the confining stress can produce such an effect, often after a time delay of minutes-to-days, is unclear, but a concentration of remotely triggered seismic events in carbon-dioxide-rich volcanic and geothermal regions suggests that an increase in pore fluid pressure associated with the nucleation and growth of carbon-dioxide gas bubbles may reduce the effective stress in critically loaded geologic faults. While this hypothesis has been tested in bench-scale laboratory experiments, field detection of seismically initiated gas bubble growth in groundwater may provide further evidence for this remote triggering mechanism. In the present study, a hydrophone continuously records the acoustic power spectrum in CH-10B, a hydrothermal well located in Long Valley Caldera, California - a site that is susceptible to remotely seismic triggering. This well exhibits co-seismic changes in water level in response to near and distant earthquakes, including every magnitude-six or greater at any location on Earth. Exploiting the inverse relationship between gas bubble radius and the peak acoustic frequency emitted when a gas bubble ruptures, this investigation seeks to detect changes in the acoustic power spectrum arising from a shift in the size-distribution or count rate of rupturing gas bubbles, coincident with a distant earthquake. By resolving the timing and intensity of the onset of a change in gas bubble rupture rate after the passage of seismic wave from a distant source, it may be possible to establish the extent to which seismically initiated gas bubble growth contributes to co-seismic borehole water level response, pore fluid pressure perturbations, and the onset of remotely triggered seismicity.

  9. Layered seismic anisotropy at Icelandic volcanoes: implications for crustal growth and consequences for shear wave splitting monitoring.

    NASA Astrophysics Data System (ADS)

    Johnson, Jessica; White, Robert; Roman, Diana; Greenfield, Tim

    2015-04-01

    The measurement of seismic anisotropy using the method of shear wave splitting (SWS) has potential as a stress monitoring tool and is increasingly being used by researchers. Even though anisotropy, caused by preferentially aligned microcracks, can be a valid proxy for determining the stress regime in the subsurface, there are many other reasons that SWS may be observed. Anisotropy in the crust may be due to aligned macroscopic fractures, layering, or aligned minerals. Temporal changes in SWS may be an artefact of migrating sources passing through a heterogeneous anisotropic field. We have analysed shear wave splitting at four volcanic areas in Iceland using unbiased, automated methods. At Upptyppingar, we observe a strong dependence of shear wave splitting parameters with source earthquake depth. At Hekla, we observe incoming polarisations radial to the volcano, while the fast wavelets are consistent with tectonic stress. Both of these observations suggest a vertical variation of seismic anisotropy. With this in mind, investigation of previously published data sets showed that this effect is apparent at the majority of volcanic areas in Iceland, if not the whole island. The layering of shear wave splitting can be interpreted in multiple ways but we favour the model of a stress discontinuity at depth, which has profound consequences for the migration of melt and formation of the crust under Iceland. This result should also be considered when using shear wave splitting as a monitoring tool as it shows that it is not only lateral variations that can create apparent temporal changes, but also varying depth of earthquake sources.

  10. Monitoring unrest in a subglacial volcano by combining thermal, meltwater conductivity and seismic signals: The Katla caldera, Iceland

    NASA Astrophysics Data System (ADS)

    Gudmundsson, Magnus T.; Hognadóttir, Þórdís; Vogfjord, Kristín; Magnusson, Eyjólfur; Reynolds, Hanna I.; Roberts, Matthew

    2014-05-01

    Highly active ice-covered volcanoes pose problems for some of the methods used for monitoring unrest associated with magma movements in the crust. Glacier surfaces are subjected to meteorological and seasonal fluctuations in elevation at time scales ranging from hours/days to years. Such fluctuations limit the applicability of inSAR and GPS, and in general the detection of crustal deformation signals. Nunataks provide sites for GPS bench marks but the seasonal fluctuations in ice cover elevation and subglacial water pressure generate associated fluctuations in observed ground deformation. The Katla caldera in south Iceland is filled with 400-700 m thick ice, has seasonal variations in surface elevation of ~10 m and basal water pressure variations suspected to be of the order of 1 MPa. Geothermal activity within the caldera is manifested as 15-20 depressions in the ice surface, typically 500-1000 m wide and 15-50 m deep. The depressions, also called ice cauldrons, are formed by geothermal melting at the base of the glacier. At some of these cauldrons meltwater collects at the glacier base and stored for some weeks or months before being drained in small outburst floods. At other cauldrons the meltwater at the base is drained away continuously, releasing geothermal waters into the rivers draining the glacier. The size and depth of the ice cauldrons in Katla has been monitored by regular overflights with a radar that measures surface elveation profiles along the flight lines. A time series of cauldron variations has been obtained since 1999. Over the same period semi-continuous records of electrical conductivity in rivers draining from the outlet glaciers from the caldera have been obtained. The data show variations in geothermal output and conductivity that broadly correlate with seismic activity. Most of the seismicity occurs at less than 2-3 km depth, in swarms consisting mostly of earthquakes of sizes <2.5-3. On a time scale of months- to-years, increases in

  11. Monitoring the 2011 Tohoku-Oki waves without sismometers: from rupture initiation to seismic and tsunami waves

    NASA Astrophysics Data System (ADS)

    Lognonne, P.; Makela, J.; Rolland, L.; Occhipinti, G.; Astafyeva, E.; Coisson, P.; Mann, M.; Kherani, A.; Sladen, A.

    2012-04-01

    Seismic and tsunami waves caused by the 11 March 2011 Tohoku mega-quake generated Pacific-wide ionospheric signals from the coupling between ground/sea/atmosphere/ionosphere. High-quality observations of the ionospheric signals have been performed using the dense GPS network located in Japan, and less dense networks in Hawaii and Chile, but also for the first time with airglow measurements, which image the 630nm light emission of the ionosphere, when it is disturbed by the propagating tsunami. Signals have not only been recorded during and after the rupture and first arrivals of seismo-acoustic waves and gravito-tsunamic waves, but also possibly prior these signals, suggesting a slow-slip event prior the seismic rupture initiation. Over Japan, all the different waves are clearly observed by GPS ionospheric sounding, and the first signals peak in the ionosphere about 8 minutes after the quake and therefore about 17 minutes prior the first arrival of the tsunami on the coast. We show that these signals provide key information on the rupture surface and the vertical sea level amplitude. We also observe clear atmospheric resonances, as well as Rayleigh and Tsunami waves, in addition to the acoustic waves. In Hawaii and possibly in Chili, co-located GPS-airglow measurements of the ionospheric response to the tsunami have been performed for the first time, and provide an unprecedent sensitivity to very long (~1 hr-10 minutes) waves. These data provide movies of the propagating tsunami front, and show also its diffraction by the Hawaii Islands. The Hawaii observations indicate that the first ionospheric waves are observed approximately one hour before the arrival time of the tsunami. We propose that these low-frequency signals are associated with a Slow Slip Event possibly associated to the initiation of the mega-quake and that the monitoring of atmospheric waves in the ionosphere with dense GNSS and airglow systems might open a new temporal window in the observation of

  12. The entrance of the Izmit Gulf : a key site for monitoring gas emissions and seismicity in the Sea of Marmara

    NASA Astrophysics Data System (ADS)

    Gasperini, Luca; Polonia, Alina; Favali, Paolo; Marinaro, Giuditta; Etiope, Giuseppe; Namık Ćaǧatay, M.; Henry, Pierre; Geli, Louis

    2010-05-01

    The Sea of Marmara has been widely recognized as a seismic gap that will be probably filled in the next decades by a large (M >=7) earthquake along the North Anatolian Fault (NAF) system. Accordingly, new research activities started in the last years, and the possibility of installing seafloor observatories, considered. Only long-term observatories allow continuous observation of large numbers of parameters. This capability is crucial for observing natural processes that are either very episodic, or statistically require long time series to be detected. Among these phenomena, gas seepage at the seabed, occurring in various locations in the Sea of Marmara (Geli et al., 2008) may be sensitive to seismicity, providing possible precursor signals. Several lines of evidence suggest that the Gulf of Izmit, in the eastern Sea of Marmara, is a key area for monitoring the activity of the NAF through seismometers and gas sensors, because: 1) it is an area characterized by a "focusing" of the NAF principal deformation zone into a single strike-slip fault, along which the dextral strike-slip rate averaged over geological times (10 mm/y) has been measured (Polonia et al., 2004); 2) it is close to the western end of the surface rupture associated with the 1999 Izmit earthquake; thus, it is a probable area where the next earthquake will nucleate; 3) it is characterized by gas and fluids emission related to the fault activity, as documented by acoustic images of the water-column and direct observations carried out using ROVs (Gasperini et al., 2009). The methane and hydrogen sulphide escape is also confirmed by the presence of "black patches" at the seafloor observed during MarNaut cruise. Seafloor multi-parameters monitoring in this area is therefore essential to unravel relationships between geochemical, physical and geophysical parameters and the mechanical behaviour of faults; the information could then be used for seismic risk assessments and to define early-warning strategies

  13. INL Seismic Monitoring Annual Report: January 1, 2004 - December 31, 2004

    SciTech Connect

    S. Payne; A. Holland; J. Hodges; R. Berg

    2005-09-01

    During 2004, INL analyzed more than 2,300 earthquakes. There were 487 earthquakes with magnitudes up to 4.0 located within the 161-km (100-mile) radius of the Idaho National Laboratory (INL). Seventeen small to moderate earthquakes of magnitudes from 3.0 to 5.0 occurred with the region outside the 161-km radius. Earthquakes activity occurred in areas that have experienced seismic activity in the past, the Basin and Range northwest of the INL, southwestern Montana, Yellowstone Park, Wyoming, Jackson, Wyoming, and southeastern Idaho. One earthquake was located northeast of Idaho Falls, Idaho within the eastern Snake River Plain (ESRP). No earthquakes were located within the INL boundaries. Earthquakes were not recorded by strong-motion accelerographs located in INL facilities.

  14. A robust satellite technique for monitoring seismically active areas: The case of Bhuj Gujarat earthquake

    NASA Astrophysics Data System (ADS)

    Genzano, N.; Aliano, C.; Filizzola, C.; Pergola, N.; Tramutoli, V.

    2007-02-01

    A robust satellite data analysis technique (RAT) has been recently proposed as a suitable tool for satellite TIR surveys in seismically active regions and already successfully tested in different cases of earthquakes (both high and medium-low magnitudes). In this paper, the efficiency and the potentialities of the RAT technique have been tested even when it is applied to a wide area with extremely variable topography, land coverage and climatic characteristics (the whole Indian subcontinent). Bhuj-Gujarat's earthquake (occurred on 26th January 2001, MS ˜ 7.9) has been considered as a test case in the validation phase, while a relatively unperturbed period (no earthquakes with MS ≥ 5, in the same region and in the same period) has been analyzed for confutation purposes. To this aim, 6 years of Meteosat-5 TIR observations have been processed for the characterization of the TIR signal behaviour at each specific observation time and location. The anomalous TIR values, detected by RAT, have been evaluated in terms of time-space persistence in order to establish the existence of actually significant anomalous transients. The results indicate that the studied area was affected by significant positive thermal anomalies which were identified, at different intensity levels, not far from the Gujarat coast (since 15th January, but with a clearer evidence on 22nd January) and near the epicentral area (mainly on 21st January). On 25th January (1 day before Gujarat's earthquake) significant TIR anomalies appear on the Northern Indian subcontinent, showing a remarkable coincidence with the principal tectonic lineaments of the region (thrust Himalayan boundary). On the other hand, the results of the confutation analysis indicate that no meaningful TIR anomalies appear in the absence of seismic events with MS ≥ 5.

  15. New insights into the potential of seismic measurements as bedload monitoring technique for a wide range of gravel-bed rivers

    NASA Astrophysics Data System (ADS)

    Barrière, J.; Oth, A.; Hostache, R.; Krein, A.

    2015-12-01

    Bedload monitoring based on seismological observations has recently emerged as a viable non-invasive measurement technique. However, its applications have only been shown for sediment transport in steep mountain rivers. We evaluated for the first time the potential of seismology for bedload transport monitoring in a rural gravel bed stream (Koulbich river in Luxembourg), characterized by low gradient (around 0.6%), small flowrate (<2.3 m3/s) and D50 transported (around 5 mm on average). The dominant anthropogenic noise in the area of investigation greatly complexified the seismic analysis but was successfully eliminated in order to extract the river's imprint on the ambient seismic field. Additional in-situ hydroacoustic measurements of bedload motion (co-located impact-plate device) and 3D hydro-morphodynamic modeling were performed to help interpreting this river's seismic signature likely dominated by water turbulences. From previous laboratory flume experiments, a calibration model was obtained between the amplitude/spectral attributes of impact measurements and the grain size of transported material, leading to an unprecedented estimation of bedload median grain size (D50) at high temporal resolution (minutes ranges) using impact-plate system. For the studied natural flood event, both simulated and estimated D50 from impact-plate measurements exhibit near-simultaneous increases, a similar temporal evolution and the same order of magnitude. The joint analysis of seismic data with hydroacoustic records and sediment transport simulation showed that the seismic records in close proximity of the stream contain evidence of bedload transport, especially in form of hysteresis behavior. These results underline the potential of non-invasive seismic measurements to estimate the triggering of bedload transport for a broader range of river systems and grain sizes than previously investigated. This study also confirms the potential of impact-plate device as robust

  16. Real-Time seismic waveforms monitoring with BeiDou Navigation Satellite System (BDS) observations for the 2015 Mw 7.8 Nepal earthquake

    NASA Astrophysics Data System (ADS)

    Geng, T.

    2015-12-01

    Nowadays more and more high-rate Global Navigation Satellite Systems (GNSS) data become available in real time, which provide more opportunities to monitor the seismic waveforms. China's GNSS, BeiDou Navigation Satellite System (BDS), has already satisfied the requirement of stand-alone precise positioning in Asia-Pacific region with 14 in-orbit satellites, which promisingly suggests that BDS could be applied to the high-precision earthquake monitoring as GPS. In the present paper, real-time monitoring of seismic waveforms using BDS measurements is assessed. We investigate a so-called "variometric" approach to measure real-time seismic waveforms with high-rate BDS observations. This approach is based on time difference technique and standard broadcast products which are routinely available in real time. The 1HZ BDS data recorded by Beidou Experimental Tracking Stations (BETS) during the 2015 Mw 7.8 Nepal earthquake is analyzed. The results indicate that the accuracies of velocity estimation from BDS are 2-3 mm/s in horizontal components and 8-9 mm/s in vertical component, respectively, which are consistent with GPS. The seismic velocity waveforms during earthquake show good agreement between BDS and GPS. Moreover, the displacement waveforms is reconstructed by an integration of velocity time series with trend removal. The displacement waveforms with the accuracy of 1-2 cm are derived by comparing with post-processing GPS precise point positioning (PPP).

  17. Seismic monitoring of hydraulic fracturing: techniques for determining fluid flow paths and state of stress away from a wellbore

    SciTech Connect

    Fehler, M.; House, L.; Kaieda, H.

    1986-01-01

    Hydraulic fracturing has gained in popularity in recent years as a way to determine the orientations and magnitudes of tectonic stresses. By augmenting conventional hydraulic fracturing measurements with detection and mapping of the microearthquakes induced by fracturing, we can supplement and idependently confirm information obtained from conventional analysis. Important information obtained from seismic monitoring includes: the state of stress of the rock, orientation and spacing of the major joint sets, and measurements of rock elastic parameters at locations distant from the wellbore. While conventional well logging operations can provide information about several of these parameters, the zone of interrogation is usually limited to the immediate proximity of the borehole. The seismic waveforms of the microearthquakes contain a wealth of information about the rock in regions that are otherwise inaccessible for study. By reliably locating the hypocenters of many microearthquakes, we have inferred the joint patterns in the rock. We observed that microearthquake locations do not define a simple, thin, planar distribution, that the fault plane solutions are consistent with shear slippage, and that spectral analysis indicates that the source dimensions and slip along the faults are small. Hence we believe that the microearthquakes result from slip along preexisting joints, and not from tensile extension at the tip of the fracture. Orientations of the principal stresses can be estimated by using fault plane solutions of the larger microearthquakes. By using a joint earthquake location scheme, and/or calibrations with downhole detonators, rock velocities and heterogeneities thereof can be investigated in rock volumes that are far enough from the borehole to be representative of intrincis rock properties.

  18. Passive seismic monitoring of hydraulic fracture experiments at the Multiwell Experiment site

    SciTech Connect

    Thorne, B.J.; Morris, H.E.

    1988-08-01

    Redesign of hardware, software, and data-reduction techniques associated with the Sandia National Laboratories' Borehole Seismic System (BSS) have made possible better estimates of hydraulic fracture geometry at the Multiwell Experiment (MWX) site. The redesigned system now incorporates four geophones per axis and provides up to 112 dB of downhole gain, for 100 times the sensitivity of the original system. Improved signal-to-noise ratios, extended frequency response and increased digitization rates have made possible the acquisition and processing of data which were previously inaccessible. A maximum likelihood event location scheme, which incorporates an algorithm based on the use of spherical statistics, is used to compute the location of microseismic events and error estimates for these locations. Accuracy estimates for the redesigned system, based on the ability to locate perforation shots, indicates a 25 ft (7.6 m) uncertainty in the location of individual microseismic events using data from two BSS receivers. This resulted in a high level of confidence in determination of the azimuth of the November 1, 1986, hydraulic fracture in the Fluvial B sandstone. A reasonable determination of the azimuth, propped wing length and height for the September 23, 1987, hydraulic fracture in the Fluvial E sandstone was possible using data from only one BSS receiver. 15 refs., 32 figs., 6 tabs.

  19. Fluid and Rock Property Controls On Production And Seismic Monitoring Alaska Heavy Oils

    SciTech Connect

    Liberatore, Matthew; Herring, Andy; Prasad, Manika; Dorgan, John; Batzle, Mike

    2012-10-30

    The goal of this project is to improve recovery of Alaskan North Slope (ANS) heavy oil resources in the Ugnu formation by improving our understanding of the formation's vertical and lateral heterogeneities via core evaluation, evaluating possible recovery processes, and employing geophysical monitoring to assess production and modify production operations.

  20. INL Seismic Monitoring Annual Report: January 1, 2006 - December 31, 2006

    SciTech Connect

    S. J. Payne; N. S. Carpenter; J. M. Hodges; R. G. Berg

    2007-09-01

    During 2006, the Idaho National Laboratory (INL) recorded 1998 independent triggers from earthquakes both within the region and from around the world. Fifteen small to moderate size earthquakes ranging in magnitude from 3.0 to 4.5 occurred within and outside the 161-km (100-mile) radius of INL. There were 357 earthquakes with magnitudes up to 4.5 that occurred within the 161-km radius of the INL. The majority of earthquakes occurred in the Basin and Range Province surrounding the eastern Snake River Plain (ESRP). The largest of these earthquakes had a body-wave magnitude (mb) 4.5 and occurred on February 5, 2006. It was located northeast of Spencer, Idaho near the east-west trending Centennial fault along the Idaho-Montana border. The earthquake did not trigger SMAs located within INL buildings. Three earthquakes occurred within the ESRP, two of which occurred within the INL boundaries. One earthquake of coda magnitude (Mc) 1.7 occurred on October 18, 2006 and was located southeast of Pocatello, Idaho. The two earthquakes within the INL boundaries included the local magnitude (ML) 2.0 on July 31, 2006 located near the southern termination of the Lemhi fault and the Mc 0.4 on August 6, 2006 located near the center of INL. The ML 2.0 earthquake was well recorded by most of the INL seismic stations and had a focal depth of 8.98 km. First motions were used to compute a focal mechanism, which indicated normal faulting along one of two possible fault planes that may strike N76ºW and dip 70±3ºSW or strike N55ºW and dip 20±13ºNE. Slip along a normal fault that strikes N76ºW and dips 70±3ºSW is consistent with slip along a possible segment of the NW-trending Lemhi normal fault.

  1. Imaging the magmatic system of Newberry Volcano using Joint active source and teleseismic tomography

    NASA Astrophysics Data System (ADS)

    Heath, Benjamin A.; Hooft, Emilie E. E.; Toomey, Douglas R.; Bezada, Maximiliano J.

    2015-12-01

    In this paper, we combine active and passive source P wave seismic data to tomographically image the magmatic system beneath Newberry Volcano, located east of the Cascade arc. By using both travel times from local active sources and delay times from teleseismic earthquakes recorded on closely spaced seismometers (300-800 m), we significantly improve recovery of upper crustal velocity structure (<10 km depth). The tomographic model reveals a low-velocity feature between 3 and 5 km depth that lies beneath the caldera, consistent with a magma body. In contrast to earlier tomographic studies, where elevated temperatures were sufficient to explain the recovered low velocities, the larger amplitude low-velocity anomalies in our joint tomography model require low degrees of partial melt (˜10%), and a minimum melt volume of ˜2.5 km3. Furthermore, synthetic tests suggest that even greater magnitude low-velocity anomalies, and by inference larger volumes of magma (up to 8 km3), are needed to explain the observed waveform variability. The lateral extent and shape of the inferred magma body indicates that the extensional tectonic regime at Newberry influences the emplacement of magmatic intrusions. Our study shows that jointly inverting active source and passive source seismic data improves tomographic imaging of the shallow crustal seismic structure of volcanic systems and that active source experiments would benefit from longer deployment times to also record teleseismic sources.

  2. An FP7 "Space" project: Aphorism "Advanced PRocedures for volcanic and Seismic Monitoring"

    NASA Astrophysics Data System (ADS)

    Di Iorio, A., Sr.; Stramondo, S.; Bignami, C.; Corradini, S.; Merucci, L.

    2014-12-01

    APHORISM project proposes the development and testing of two new methods to combine Earth Observation satellite data from different sensors, and ground data. The aim is to demonstrate that this two types of data, appropriately managed and integrated, can provide new improved GMES products useful for seismic and volcanic crisis management. The first method, APE - A Priori information for Earthquake damage mapping, concerns the generation of maps to address the detection and estimate of damage caused by a seism. The use of satellite data to investigate earthquake damages is not an innovative issue. We can find a wide literature and projects concerning such issue, but usually the approach is only based on change detection techniques and classifications algorithms. The novelty of APE relies on the exploitation of a priori information derived by InSAR time series to measure surface movements, shake maps obtained from seismological data, and vulnerability information. This a priori information is then integrated with change detection map to improve accuracy and to limit false alarms. The second method deals with volcanic crisis management. The method, MACE - Multi-platform volcanic Ash Cloud Estimation, concerns the exploitation of GEO (Geosynchronous Earth Orbit) sensor platform, LEO (Low Earth Orbit) satellite sensors and ground measures to improve the ash detection and retrieval and to characterize the volcanic ash clouds. The basic idea of MACE consists of an improvement of volcanic ash retrievals at the space-time scale by using both the LEO and GEO estimations and in-situ data. Indeed the standard ash thermal infrared retrieval is integrated with data coming from a wider spectral range from visible to microwave. The ash detection is also extended in case of cloudy atmosphere or steam plumes. APE and MACE methods have been defined in order to provide products oriented toward the next ESA Sentinels satellite missions.The project is funded under the European Union FP7

  3. Seismic array monitoring of mortar fire during the November 2005 ARL-NATO TG-53 field experiment at YPG

    NASA Astrophysics Data System (ADS)

    Anderson, Thomas S.; Fisk, David J.; Fiori, John E.; Decato, Stephan N.; Punt, Douglas A.; Lamie, N.

    2006-05-01

    The U.S. Army Corps of Engineers Engineer Research and Development Center (ERDC) participated in a joint ARL-NATO TG-53 field experiment and data collection at Yuma Proving Ground, AZ, in early November 2005. Seismic and acoustic signatures from both muzzle blasts and impacts of small arms fire and artillery were recorded using seven seismic arrays and three acoustic arrays. Arrays composed of 12 seismic and 12 acoustic sensors each were located from 700 m to 18 km from gun positions. Preliminary analysis of signatures attributed to 60-mm, 81-mm, and 120-mm mortars recorded at a seismic-acoustic array 1.1 km from gun position are presented. Seismic and acoustic array f-k analysis is performed to detect and characterize the source signature. Horizontal seismic data are analyzed to determine efficacy of a seismic discriminant for mortar and artillery sources. Rotation of North and East seismic components to radial and transverse components relative to the source-receiver path provide maximum surface wave amplitude on the transverse component. Angles of rotation agree well with frequency-wavenumber (f-k) analysis of both seismic and acoustic signals. The spectral energy of the rotated transverse surface wave is observable on all caliber of mortars at a distance of 1.1 km and is a reliable source discriminant for mortar sources at this distance.

  4. Monitoring volcano precursory activity with the materials failure approach, using rates of cumulative seismic coda length

    SciTech Connect

    Cornelius, R.R.; Voight, B. . Dept. of Geosciences)

    1992-01-01

    The proportionality between the energy, E, of an elastic wave and the square of its amplitude led to the usage of Benioff diagrams'' for purposes of volcano monitoring. These diagrams show the time-integrated amplitude as [radical]E versus time. The authors propose to use accelerating cumulative coda length directly in volcano monitoring. This surrogate measure of energy'' is used for practical reasons, as it eliminates the intermediate step required for energy calculations with regional and instrument-specific constants. Rates of cumulative coda (s/day) may be used for the materials failure approach'' to eruption prediction, which fits data according to an empirical rate-acceleration relationship. The method allows numerical or graphical rate extrapolation towards the expected failure rate; eruption windows may be established. Rate series derived from either cumulative amplitude, cumulative coda, or calculated [radical]E can be analyzed by the materials failure approach equally well; neither series is favored by this method because of similar characteristics. They suggest rate interpolation from the time-integrated data over constant coda-increments instead of over constant time-increments. This results in an increasingly higher frequency of rate data towards the end of an accelerating time series. The end-weighted rate calculation emphasizes the latest precursory developments while it smooths noise at lower rates. Adjusting the applied constant coda-increment for rate calculations as a function of total encountered coda, is a technique for an automated and sequential update of the extrapolated failure time.

  5. Monitoring studies of slide system under the action of seismic impacts

    NASA Astrophysics Data System (ADS)

    Frolov, Anton

    2013-04-01

    The immediate detection of landslide activity that is provided by real-time systems can be crucial in saving human lives and protecting property. Traditional field observations, even if taken regularly, cannot detect changes at the moment they occur. Moreover, active landslides can be hazardous to work on, and large movements often occur during storms when visibility is poor. The continuous data provided by remote real-time monitoring permits a better understanding of dynamic landslide behavior that, in turn, enables engineers to create more effective designs to prevent or halt landslides. Monitoring of the coastal zone involves the following block diagram: input - processing -output - feed-back. We feed the input with data on a studied technogenous loading on the coastal zone, and the input presents the analysis of motion of a geological medium and the subsequent forecast of evolution of its lithodynamic characteristics. The submitted report describes a practical system of monitoring for the Central Livadiya Slide System (CLSSC) of the Crimea, which is intended for the diagnostics of a lithodynamic situation in the real-time mode, conducting the data base on heliogenous and lithogenous parameters, and predicting a future state of the slide-containing system. In the system of monitoring of a state of CLSSC, which is realized on a computer, the registered heliogenous parameters include the level of solar activity, changes in temperature and moisture regimes, changes in the character and intensity of precipitations, the wind velocity, etc. In this case, data are introduced into the computer in the manual mode. Lithogenous parameters are presented by a collection of conditions and factors characterizing the mechanism and dynamics of changes in the equilibrium state of slopes of CLSSC. The control over the evolution of lithogenous parameters is realized in the following way: 1. The control over movement of the control points on the surface of active slides is carried

  6. Multicomponent seismic monitoring of the effective stimulated volume associated with hydraulic fracture stimulations in a shale reservoir, Pouce Coupe field, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Steinhoff, Christopher

    The Reservoir Characterization Project in conjunction with Talisman Energy Inc., have been investigating a time-lapse data set acquired during hydraulic fracture stimulations of two horizontal wells in the Montney Shale at Pouce Coupe Field, Alberta, Canada. Multicomponent seismic surveys and microseismic data were acquired in December 2008 and integrated in this study with multiscale, multidisciplinary reservoir characterization techniques, including geomechanics and production data, to monitor changes within the reservoir associated with the hydraulic fracture stimulations. The goal of this investigation was to study the feasibility of microseismic and time-lapse multicomponent seismic data for correlating hydraulic stimulation success to the enhanced permeability pathways created during the stimulation process. Three independently acquired microseismic monitoring surveys and the detected microseismic events were analyzed to infer the fracture length, height, azimuth, and asymmetry created by the hydraulic stimulation. Integrating the interpretation objectives with the multicomponent surface seismic processing sequence elevated the level of reservoir characterization that can be performed using the Pouce Coupe converted-wave seismic data. Shear-wave splitting as observed by the newly processed converted-wave data were sensitive to fracture induced anisotropy and therefore, provided a measurement of the dominant fracture orientation and fracture density difference within the Montney reservoir interval. Before hydraulic stimulations, the natural fracture conditions resulted in a measured shear-wave splitting magnitude of 2-3%, with Baseline anomalies matching the independently interpreted minimal offset faults only visible on the converted-wave seismic data. Multistage hydraulic fracture stimulations increased the magnitude of shear-wave splitting up to 8%, well above the background noise level of 1%. The natural fractures and faults acted as conduits or barriers

  7. Brownfield site investigation: a new technology for the detection of large objects based on passive seismic monitoring

    NASA Astrophysics Data System (ADS)

    Pytharouli, S.; Aspray, T. J.; Grojean, Q.; Steirou, E.

    2013-12-01

    In assessing brownfield sites for redevelopment, intrusive investigations are carried out to assess contamination, geology and hydrogeology. Such investigations are expensive, requiring the hire of expensive equipment, which incur standing charges when not in use. In addition, they provide information for discrete sample ';windows'. Non-intrusive methods have the ability to gather information across an entire area. Methods including electrical resistivity/conductivity and ground penetrating radar (GRP), and have been applied to brownfield sites. Their ability in detecting pollution e.g. buried canisters, is often restricted due to unfavourable on-site conditions e.g. GRP is not useful in cases where a layer of clay or reinforced concrete is present. This study is focused on the use, for the first time, of short period seismometers as an alternative, non-intrusive, passive seismic method to detect the presence of objects buried under the ground surface even when on-site conditions are not favourable. We used five low detection threshold seismometers with a flat response within the frequency range 1 - 80 Hz. We conducted experiments both in the lab and in the field. Three series of lab experiments were conducted in sand, under controlled conditions, using ambient noise as the only source of generating seismic waves. Results revealed that there is a distinct difference in the amplitude of the power density spectra of the recorded signals in cases where objects e.g. concrete block, polystyrene block, wood, were present. To validate these results in field scale, we conducted a series of experiments that took place in Heriot-Watt University campus on a field for which we had information for the subsurface from an electromagnetic survey. We used the same monitoring equipment to try and detect the presence of a 6m long PVC pipe buried 0.5m below the ground surface. Results were consistent with those obtained from lab experiments. This supports our initial hypothesis on the

  8. Seismic risk mitigation in deep level South African mines by state of the art underground monitoring - Joint South African and Japanese study

    NASA Astrophysics Data System (ADS)

    Milev, A.; Durrheim, R.; Nakatani, M.; Yabe, Y.; Ogasawara, H.; Naoi, M.

    2012-04-01

    Two underground sites in a deep level gold mine in South Africa were instrumented by the Council for Scientific and Industrial Research (CSIR) with tilt meters and seismic monitors. One of the sites was also instrumented by JApanese-German Underground Acoustic emission Research in South Africa (JAGUARS) with a small network, approximately 40m span, of eight Acoustic Emission (AE) sensors. The rate of tilt, defined as quasi-static deformations, and the seismic ground motion, defined as dynamic deformations, were analysed in order to understand the rock mass behavior around deep level mining. In addition the high frequency AE events recorded at hypocentral distances of about 50m located at 3300m below the surface were analysed. A good correspondence between the dynamic and quasi-static deformations was found. The rate of coseismic and aseismic tilt, as well as seismicity recorded by the mine seismic network, are approximately constant until the daily blasting time, which takes place from about 19:30 until shortly before 21:00. During the blasting time and the subsequent seismic events the coseismic and aseismic tilt shows a rapid increase.Much of the quasi-static deformation, however, occurs independently of the seismic events and was described as 'slow' or aseismic events. During the monitoring period a seismic event with MW 2.2 occurred in the vicinity of the instrumented site. This event was recorded by both the CSIR integrated monitoring system and JAGUARS acoustic emotion network. The tilt changes associated with this event showed a well pronounced after-tilt. The aftershock activities were also well recorded by the acoustic emission and the mine seismic networks. More than 21,000 AE aftershocks were located in the first 150 hours after the main event. Using the distribution of the AE events the position of the fault in the source area was successfully delineated. The distribution of the AE events following the main shock was related to after tilt in order to

  9. Second and Third Quarters Hanford Seismic Report for Fiscal Year 1999

    SciTech Connect

    Hartshorn, Donald C.; Reidel, Stephen P.; Rohay, Alan C.

    1999-10-08

    Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) for the U.S. Department of Energy and its contractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site.

  10. Definition of a unique model for the improvement of the monitoring network and seismic risk reduction of the school buildings in Italy

    NASA Astrophysics Data System (ADS)

    Greco, M.; Console, R.; Colangelo, A.; Cioè, A.; Trivigno, L.

    2015-12-01

    In the latest decade the safety of the Italian schools against seismic risk is a crucial subject for the Italian legislation as well as to the UN Convention on the DRR and the more specific priorities adopted even within the OECD. Recently, the Italian Parliament approved a law (L98/2013) which launched the Commissioning Safety of School Buildings Plan and the Definition of a Unique Model, to be developed by the CGIAM, in order to improve monitoring network and seismic risk reduction (SRR). The objectives of such a law deals with increasing in the knowledge of public actions aimed to improve the effectiveness of the SRR policy on school buildings. The actions of the CGIAM will consist in the identification of a significant number of school buildings in Italy, mainly in terms of type of construction and material, on which calibrate specific synthetic parameters and test models. Furthermore, the activities are addressed to quantitatively evaluation of intervention efficacy, to set up simple systems of instrumental monitoring, even able to test the possibility of periodical checks of the state of general preservation. The main issues carried on by the CGIAM mainly concern the completion and enrichment of the existing data base of school buildings, even through the collaboration of the Ministries and other relevant Italian research institutions, the evaluation of seismic hazard and site condition analysis as well as the definition of other seismic risk factors. Nevertheless a cost-benefit analysis as well as application and dissemination of such tools are proposed too. At the same time, the CGIAM contributes to the definition of experimental installation and use of a Simplified Accelerometric Monitoring Network for school buildings comprehensive of testing phase on a limited number of structures. The work proposes a synthetic overview of the employed methodologies as well as the first results arising from the research and implementation activities.

  11. Quantitative assessment of seismic source performance: Feasibility of small and affordable seismic sources for long term monitoring at the Ketzin CO2 storage site, Germany

    NASA Astrophysics Data System (ADS)

    Sopher, Daniel; Juhlin, Christopher; Huang, Fei; Ivandic, Monika; Lueth, Stefan

    2014-08-01

    We apply a range of quantitative pre-stack analysis techniques to assess the feasibility of using smaller and cheaper seismic sources, than those currently used at the Ketzin CO2 storage site. Results from two smaller land sources are presented alongside those from a larger, more powerful source, typically utilized for seismic acquisition at the Ketzin. The geological target for the study is the Triassic Stuttgart Formation which contains a saline aquifer currently used for CO2 storage. The reservoir lies at a depth of approximately 630 m, equivalent to a travel time of 500 ms along the study profile. The three sources discussed in the study are the Vibsist 3000, Vibsist 500 (using industrial hydraulic driven concrete breaking hammers) and a drop hammer source. Data were collected for the comparison using the three sources in 2011, 2012 and 2013 along a 984 m long line with 24 m receiver spacing and 12 m shot spacing. Initially a quantitative analysis is performed of the noise levels between the 3 surveys. The raw shot gathers are then analyzed quantitatively to investigate the relative energy output, signal to noise ratio, penetration depth, repeatability and frequency content for the different sources. The performance of the sources is also assessed based on stacked seismic sections. Based on the results from this study it appears that both of the smaller sources are capable of producing good images of the target reservoir and can both be considered suitable as lower cost, less invasive sources for use at the Ketzin site or other shallow CO2 storage projects. Finally, the results from the various pre-stack analysis techniques are discussed in terms of how representative they are of the final stacked sections.

  12. Seismic Computerized Alert Network

    USGS Publications Warehouse

    1986-01-01

    In 1985 the USGS devised a model for a Seismic Computerized Alert Network (SCAN) that would use continuous monitoring of seismic data from existing types of instruments to provide automatic, highly-reliable early warnings of earthquake shaking. In a large earthquake, substantial damaging ground motions may occur at great distances from the earthquake's epicenter.

  13. Bedload transport rates in a gravel bedded-river derived from high-resolution monitoring using seismic impact plates

    NASA Astrophysics Data System (ADS)

    Downs, Peter; Soar, Philip

    2015-04-01

    Accurate characterisation of bedload transport rates is critical for a better understanding of geomorphological process dynamics, aquatic habitats, sediment budgets and strategies for catchment-scale initiatives in sediment management under conditions of climate change. However, rate estimation is challenging in practice: direct measurements are costly and logistically difficult to achieve with acceptable accuracy over geomorphologically-relevant time periods, and the uncertainty in transport rates predicted from empirical formulae and numerical simulation is rarely below 50 per cent. Partly reflecting these issues, passive technologies for continuous bedload monitoring are becoming increasingly popular. Sensors such as seismic impact plates offer the opportunity to characterise bedload activity at exceptionally high resolution - monitoring from the River Avon, (Devon, UK) indicated that despite significant intra-event and between-plate differences in apparent bedload transport aggregated over 5-minute periods, the magnitude-frequency product of discharge and impact frequency result in a highly plausible effective discharge, supporting the potential value of impact plates as indicators of relative sediment transport loads over annual timescales. Whereas the focus in bedload rate estimation to date has been on developing satisfactory sediment rating curves from detection signals, we instead develop a method for directly estimating bedload transport rates from impact plate data as a function of intensity of transport (count, n, per second), bed material mass (kg) and cross-stream transport variability. Bulk sediment samples are converted to a mass in transit for each instantaneous discharge according to the intensity of transport and a Monte Carlo simulation of the load in transit determined at random from the bed material particle size distribution. The lower detection threshold is determined using experimental calibration and the upper size limit is determined from

  14. SeismoGeodesy: Combination of High Rate, Real-time GNSS and Accelerometer Observations and Rapid Seismic Event Notification for Earth Quake Early Warning and Volcano Monitoring

    NASA Astrophysics Data System (ADS)

    Jackson, Michael; Zimakov, Leonid; Moessmer, Matthias

    2015-04-01

    Scientific GNSS networks are moving towards a model of real-time data acquisition, epoch-by-epoch storage integrity, and on-board real-time position and displacement calculations. This new paradigm allows the integration of real-time, high-rate GNSS displacement information with acceleration and velocity data to create very high-rate displacement records. The mating of these two instruments allows the creation of a new, very high-rate (200 Hz) displacement observable that has the full-scale displacement characteristics of GNSS and high-precision dynamic motions of seismic technologies. It is envisioned that these new observables can be used for earthquake early warning studies, volcano monitoring, and critical infrastructure monitoring applications. Our presentation will focus on the characteristics of GNSS, seismic, and strong motion sensors in high dynamic environments, including historic earthquakes replicated on a shake table over a range of displacements and frequencies. We will explore the optimum integration of these sensors from a filtering perspective including simple harmonic impulses over varying frequencies and amplitudes and under the dynamic conditions of various earthquake scenarios. We will also explore the tradeoffs between various GNSS processing schemes including real-time precise point positioning (PPP) and real-time kinematic (RTK) as applied to seismogeodesy. In addition we will discuss implementation of a Rapid Seismic Event Notification System that provides quick delivery of digital data from seismic stations to the acquisition and processing center and a full data integrity model for real-time earthquake notification that provides warning prior to significant ground shaking.

  15. Sentinel-1 automatic processing chain for volcanic and seismic areas monitoring within the Geohazards Exploitation Platform (GEP)

    NASA Astrophysics Data System (ADS)

    De Luca, Claudio; Zinno, Ivana; Manunta, Michele; Lanari, Riccardo; Casu, Francesco

    2016-04-01

    The microwave remote sensing scenario is rapidly evolving through development of new sensor technology for Earth Observation (EO). In particular, Sentinel-1A (S1A) is the first of a sensors' constellation designed to provide a satellite data stream for the Copernicus European program. Sentinel-1A has been specifically designed to provide, over land, Differential Interferometric Synthetic Aperture Radar (DInSAR) products to analyze and investigate Earth's surface displacements. S1A peculiarities include wide ground coverage (250 km of swath), C-band operational frequency and short revisit time (that will reduce from 12 to 6 days when the twin system Sentinel-1B will be placed in orbit during 2016). Such characteristics, together with the global coverage acquisition policy, make the Sentinel-1 constellation to be extremely suitable for volcanic and seismic areas studying and monitoring worldwide, thus allowing the generation of both ground displacement information with increasing rapidity and new geological understanding. The main acquisition mode over land is the so called Interferometric Wide Swath (IWS) that is based on the Terrain Observation by Progressive Scans (TOPS) technique and that guarantees the mentioned S1A large coverage characteristics at expense of a not trivial interferometric processing. Moreover, the satellite spatial coverage and the reduced revisit time will lead to an exponential increase of the data archives that, after the launch of Sentine-1B, will reach about 3TB per day. Therefore, the EO scientific community needs from the one hand automated and effective DInSAR tools able to address the S1A processing complexity, and from the other hand the computing and storage capacities to face out the expected large amount of data. Then, it is becoming more crucial to move processors and tools close to the satellite archives, being not efficient anymore the approach of downloading and processing data with in-house computing facilities. To address

  16. Microseismic monitoring of soft-rock landslide: contribution of a 3D velocity model for the location of seismic sources.

    NASA Astrophysics Data System (ADS)

    Floriane, Provost; Jean-Philippe, Malet; Cécile, Doubre; Julien, Gance; Alessia, Maggi; Agnès, Helmstetter

    2015-04-01

    Characterizing the micro-seismic activity of landslides is an important parameter for a better understanding of the physical processes controlling landslide behaviour. However, the location of the seismic sources on landslides is a challenging task mostly because of (a) the recording system geometry, (b) the lack of clear P-wave arrivals and clear wave differentiation, (c) the heterogeneous velocities of the ground. The objective of this work is therefore to test whether the integration of a 3D velocity model in probabilistic seismic source location codes improves the quality of the determination especially in depth. We studied the clay-rich landslide of Super-Sauze (French Alps). Most of the seismic events (rockfalls, slidequakes, tremors...) are generated in the upper part of the landslide near the main scarp. The seismic recording system is composed of two antennas with four vertical seismometers each located on the east and west sides of the seismically active part of the landslide. A refraction seismic campaign was conducted in August 2014 and a 3D P-wave model has been estimated using the Quasi-Newton tomography inversion algorithm. The shots of the seismic campaign are used as calibration shots to test the performance of the different location methods and to further update the 3D velocity model. Natural seismic events are detected with a semi-automatic technique using a frequency threshold. The first arrivals are picked using a kurtosis-based method and compared to the manual picking. Several location methods were finally tested. We compared a non-linear probabilistic method coupled with the 3D P-wave model and a beam-forming method inverted for an apparent velocity. We found that the Quasi-Newton tomography inversion algorithm provides results coherent with the original underlaying topography. The velocity ranges from 500 m.s-1 at the surface to 3000 m.s-1 in the bedrock. For the majority of the calibration shots, the use of a 3D velocity model

  17. Active source electromagnetic methods for marine munitions

    NASA Astrophysics Data System (ADS)

    Schultz, Gregory; Shubiditze, Fridon; Miller, Jonathan; Evans, Rob

    2011-06-01

    The detection of munitions targets obscured in coastal and marine settings has motivated the need for advanced geophysical technologies suited for underwater deployment. Building on conventional marine electromagnetic theory and based on the use of existing electric and magnetic field sensing designs, we analyze the electromagnetic fields emitted from excited targets in the frequency range between 1 kHz and 1 MHz. We present evidence that employing electromagnetic modes that are higher in frequency relative to those typically used in ground-based sensing yields greater range and sensitivity for underwater surveys. We develop potential design strategies for implementing both magnetic (B) and electric (E) field sources and sensors in the marine environment, and determine optimal arrangements for a potential combined E- and B-field sensing system. The implementation of both 1D analytical and 3D numerical simulations yields the primary and secondary field distributions in representative underwater settings for various sourcereceiver arrangements. We study the electromagnetic field distributions from both electric (voltage-fed dipole) and magnetic field (encased and submerged induction coil) active sources. Application of these concepts provide unique and useful information about targets from the addition of electric field sensing alone as well as through the combination of electric and magnetic field sensing.

  18. Multicomponent seismic monitoring of stress arching in the overburden due to hydraulic fracturing in the Montney Shale at Pouce Coupe Field, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Vinal, Irene

    Recent studies have shown convincing evidence that time-lapse changes in seismic data occur not only within the reservoir interval but also in the overburden. Observations that production at the reservoir level and subsequent decrease in pore pressure lead to modifications in the stress field and variations in the overburden have been documented (Hatchell et al., 2003; Hudson et al., 2005). The study of the opposite case, that is, the analysis of the effect in the overburden of an increase in pore pressure in the reservoir has not been so well documented yet and is the focus of this work; the possibility that the hydraulic fracturing process causes seismically detectable changes in the overburden in a time-lapse sense is studied at Pouce Coupe Field, Alberta, and the results are shown. The analysis is performed using multicomponent data from three seismic surveys acquired to evaluate the hydraulic stimulations of two horizontal wells in the Montney Shale. The time-lapse time shifts between the data of the two monitor surveys and the baseline have been calculated and constitute the main tool to study the injection-induced changes above the reservoir interval. The hypothesis is that the increase in the reservoir pressure due to the hydraulic well treatment might produce upward overburden compaction, leading to an increase in stresses that would be translated into an increase in the seismic velocities and therefore, into positive time shifts (considering monitor data subtracted from baseline data) if a time window for the overburden is analyzed. The study shows strong differences in the magnitude of the PS response to the stimulations compared to that of the PP data. The fact that mode-converted (PS) waves are more sensitive to azimuthal anisotropy than compressional waves explains the stronger character of the response observed in PS data, allowing for a more detailed interpretation of the stress-arching distribution. The time-lapse time shifts in the overburden

  19. Active seismic monitoring of changes of the reflection response of a crystalline shear zone due to fluid injection in the crust at the Continental Deep Drilling Site, Germany

    NASA Astrophysics Data System (ADS)

    Beilecke, T.; Kurt, B.; Stefan, B.

    2005-12-01

    In theory and in the laboratory variations of the hydraulic pressure can be detected with seismic methods: A lowering of the hydraulic pressure leads to the closure of micro-cracks within the rock (increase of the differential or effective pressure). Subsequently, the seismic velocities increase. An increase of the hydraulic pressure leads to reverse seismic effects. Consequently, seismic impedance contrasts and associated reflection amplitudes vary in the case of a propagating fluid pressure front in a rock matrix with inhomogeneous permeability - as is the case at shear zones. The largest amplitude changes can be expected with vertical ray inclination on the impedance contrast. Generally, the expected effects are small however (Kaselow, 2004). The practical utilization of active seismics for the detection of pressure changes at large scale in hard rock is currently being studied at the Continental Deep Drilling Site (KTB). The injection of water (200 l/min) in a depth of about 4000 m into the so-called SE2 shear zone in the KTB pilot hole was monitored with active seismics between May 2004 and April 2005. The core of the experiment layout is a fixed 5-arm geophone array consisting of 24 3-component geophones, buried at about 70 cm depth. The source signal is a vertical vibrator sweep of 30 s length with the spectrum 30-120 Hz. The signal is sent into the ground 32 times during each cycle, detected with the array and recorded separately for each geophone channel, without prior correlation with the source signal. This allows maximum post-processing with seismic processing and analysis tools and especially permits the use of array properties to increase the signal-to-noise ratio. Critical parameters of the experiment are the repeatability of the source signal as well as the stability of the receiver properties. Another pivot is the hydraulic pressure and its distribution built up within the rock matrix. Estimations based on model calculations show that a change of

  20. Seismically active area monitoring by robust TIR satellite techniques: a sensitivity analysis on low magnitude earthquakes in Greece and Turkey

    NASA Astrophysics Data System (ADS)

    Corrado, R.; Caputo, R.; Filizzola, C.; Pergola, N.; Pietrapertosa, C.; Tramutoli, V.

    2005-01-01

    Space-time TIR anomalies, observed from months to weeks before earthquake occurrence, have been suggested by several authors as pre-seismic signals. Up to now, such a claimed connection of TIR emission with seismic activity has been considered with some caution by scientific community mainly for the insufficiency of the validation data-sets and the scarce importance attached by those authors to other causes (e.g. meteorological) that, rather than seismic activity, could be responsible for the observed TIR signal fluctuations. A robust satellite data analysis technique (RAT) has been recently proposed which, thanks to a well-founded definition of TIR anomaly, seems to be able to identify anomalous space-time TIR signal transients even in very variable observational (satellite view angle, land topography and coverage, etc.) and natural (e.g. meteorological) conditions. Its possible application to satellite TIR surveys in seismically active regions has been already tested in the case of several earthquakes (Irpinia: 23 November 1980, Athens: 7 September 1999, Izmit: 17 August 1999) of magnitude higher than 5.5 by using a validation/confutation approach, devoted to verify the presence/absence of anomalous space-time TIR transients in the presence/absence of seismic activity. In these cases, a magnitude threshold (generally M<5) was arbitrarily chosen in order to identify seismically unperturbed periods for confutation purposes. In this work, 9 medium-low magnitude (4

  1. Insights into the origins of drumbeat earthquakes, periodic low frequency seismicity, and plug degradation from multi-instrument monitoring at Tungurahua volcano, Ecuador, April 2015

    NASA Astrophysics Data System (ADS)

    Bell, Andrew; Hernandez, Stephen; Gaunt, Elizabeth; Mothes, Patricia; Hidalgo, Silvana; Ruiz, Mario

    2016-04-01

    Highly-periodic repeating 'drumbeat' earthquakes have been reported from several andesitic and dacitic volcanoes. Physical models for the origin of drumbeat earthquakes incorporate, to different extents, the incremental upward movement of viscous magma. However, the roles played by stick-slip friction, brittle failure, and fluid flow, and the relations between drumbeat earthquakes and other low-frequency seismic signals, remain controversial. Here we report the results of analysis of three weeks of geophysical data recorded during an unrest episode at Tungurahua, an andesitic stratovolcano in Ecuador, during April 2015, by the monitoring network of the Instituto Geofisico of Ecuador. Combined seismic, geodetic, infrasound, and gas monitoring has provided new insights into the origins of periodic low-frequency seismic signals, conduit processes, and the nature of current unrest. Over the three-week period, the relative seismic amplitude (RSAM) correlated closely with short-term deformation rates and gas fluxes. However, the characteristics of the seismic signals, as recorded at a short-period station closest to the summit crater, changed considerably with time. Initially high RSAM and gas fluxes, with modest ash emissions, were associated with continuous and 'pulsed' tremor signals (amplitude modulated, with 30-100 second periods). As activity levels decreased over several days, tremor episodes became increasingly intermittent, and short-lived bursts of low-frequency earthquakes with quasiperiodic inter-event times were observed. Following one day of quiescence, the onset of pronounced low frequency drumbeat earthquakes signalled the resumption of elevated unrest, initially with mean inter-event times of 32 seconds, and later increasing to 74 seconds and longer, with periodicity progressively breaking down over several days. A reduction in RSAM was then followed by one week of persistent, quasiperiodic, longer-duration emergent low-frequency pulses, including

  2. Use of Preoperation Acoustic Modeling Combined with Real-Time Sound Level Monitoring to Mitigate Behavioral Effects of Seismic Surveys.

    PubMed

    Racca, Roberto; Austin, Melanie

    2016-01-01

    Underwater acoustic modeling is often used to estimate the injury radius around a seismic exploration source; only occasionally has it been applied to the mitigation of behavioral effects, where the safety boundary may extend to many kilometers. Such a mitigation strategy requires precise estimation of the sound field for many source locations and likely entails field validation over the course of the operation to ensure that mitigation regions are accurate. This article reviews the enactment of such an approach for a seismic survey off Sakhalin Island and examines how similar principles may be applied to other surveys under suitable conditions.

  3. Aftershocks series monitoring of the September 18, 2004 M = 4.6 earthquake at the western Pyrenees: A case of reservoir-triggered seismicity?

    NASA Astrophysics Data System (ADS)

    Ruiz, M.; Gaspà, O.; Gallart, J.; Díaz, J.; Pulgar, J. A.; García-Sansegundo, J.; López-Fernández, C.; González-Cortina, J. M.

    2006-10-01

    On September 18, 2004, a 4.6 mbLg earthquake was widely felt in the region around Pamplona, at the western Pyrenees. Preliminary locations reported an epicenter less than 20 km ESE of Pamplona and close to the Itoiz reservoir, which started impounding in January 2004. The area apparently lacks of significant seismic activity in recent times. After the main shock, which was preceded by series of foreshocks reaching magnitudes of 3.3 mbLg, a dense temporal network of 13 seismic stations was deployed there to monitor the aftershocks series and to constrain the hypocentral pattern. Aftershock determinations obtained with a double-difference algorithm define a narrow epicentral zone of less than 10 km 2, ESE-WNW oriented. The events are mainly concentrated between 3 and 9 km depth. Focal solutions were computed for the main event and 12 aftershocks including the highest secondary one of 3.8 mbLg. They show mainly normal faulting with some strike-slip component and one of the nodal planes oriented NW-SE and dipping to the NE. Cross-correlation techniques applied to detect and associate events with similar waveforms, provided up to 33 families relating the 67% of the 326 relocated aftershocks. Families show event clusters grouped by periods and migrating from NW to SE. Interestingly, the narrow epicentral zone inferred here is located less than 4 km away from the 111-m high Itoiz dam. These hypocentral results, and the correlation observed between fluctuations of the reservoir water level and the seismic activity, favour the explanation of this foreshock-aftershock series as a rapid response case of reservoir-triggered seismicity, burst by the first impoundment of the Itoiz reservoir. The region is folded and affected by shallow dipping thrusts, and the Itoiz reservoir is located on the hangingwall of a low angle southward verging thrust, which might be a case sensible to water level fluctuations. However, continued seismic monitoring in the coming years is mandatory in

  4. Preseismic Velocity Changes Observed from Active Source Monitoringat the Parkfield SAFOD Drill Site

    SciTech Connect

    Daley, Thomas; Niu, Fenglin; Silver, Paul G.; Daley, Thomas M.; Cheng, Xin; Majer, Ernest L.

    2008-06-10

    Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. Here we show that such stress changes are measurable by exploiting the stress dependence of seismic wave speed from an active source cross-well experiment conducted at the SAFOD drill site. Over a two-month period we observed an excellent anti-correlation between changes in the time required for an S wave to travel through the rock along a fixed pathway--a few microseconds--and variations in barometric pressure. We also observed two large excursions in the traveltime data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. Interestingly, the two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies.

  5. Characterization and application of microearthquake clusters to problems of scaling, fault zone dynamics, and seismic monitoring at Parkfield, California

    SciTech Connect

    Nadeau, R.M.

    1995-10-01

    This document contains information about the characterization and application of microearthquake clusters and fault zone dynamics. Topics discussed include: Seismological studies; fault-zone dynamics; periodic recurrence; scaling of microearthquakes to large earthquakes; implications of fault mechanics and seismic hazards; and wave propagation and temporal changes.

  6. The SeIsmic monitoring and vulneraBilitY framework for civiL protection (SIBYL) Project: An overview and preliminary results

    NASA Astrophysics Data System (ADS)

    Fleming, Kevin; Parolai, Stefano; Iervolino, Iunio; Pitilakis, Kyriazis; Petryna, Yuriy

    2016-04-01

    The SIBYL project is setting out to contribute to enhancing the capacity of Civil Protection (CP) authorities to rapidly and cost-effectively assess the seismic vulnerability of the built environment. The reason for this arises from the occurrence of seismic swarms or foreshocks, which leads to the requirement that CP authorities must rapidly assess the threatened area's vulnerability. This is especially important for those regions where there is a dearth of up-to-date and reliable information. The result will be a multi-faceted framework, made up of methodologies and software tools, that provides information to advise decision makers as to the most appropriate preventative actions to be taken. It will cover cases where there is a need for short-notice vulnerability assessment in a pre-event situation, and the monitoring of the built environment's dynamic vulnerability during a seismic sequence. Coupled with this will be the ability to stimulate long-term management plans, independent of the hazard or disaster of concern. The monitoring itself will involve low-cost sensing units which may be easily installed in critical infrastructures. The framework will be flexible enough to be employed over multiple spatial scales, and it will be developed with a modular structure which will ease its applicability to other natural hazard types. Likewise, it will be able to be adapted to the needs of CP authorities in different countries within their own hazard context. This presentation therefore provides an overview of the aims and expected outcomes of SIBYL, while explaining the tools currently being developed and refined, as well as preliminary results of several field campaigns.

  7. Using RST approach and EOS-MODIS radiances for monitoring seismically active regions: a study on the 6 April 2009 Abruzzo earthquake

    NASA Astrophysics Data System (ADS)

    Pergola, N.; Aliano, C.; Coviello, I.; Filizzola, C.; Genzano, N.; Lacava, T.; Lisi, M.; Mazzeo, G.; Tramutoli, V.

    2010-02-01

    In the last few years, Robust Satellite data analysis Techniques (RST) have been proposed and successfully applied for monitoring major natural and environmental risks. Among the various fields of application, RST analysis has been used as a suitable tool for satellite TIR surveys in seismically active regions, devoted to detect and monitor thermal anomalies possibly related to earthquake occurrence. In this work, RST has been applied, for the first time, to thermal infrared observations collected by MODIS (Moderate Resolution Imaging Spectroradiometer) - the sensor onboard EOS (Earth Observing System) satellites - in the case of Abruzzo (Italy) earthquake occurred on 6 April 2009 (ML~5.8). First achievements, shown in this work, seem to confirm the sensitivity of the proposed approach in detecting perturbations of the Earth's emission thermal field few days before the event. The reliability of such results, based on the analysis of 10 years of MODIS observations, seems to be supported by the results achieved analyzing the same area in similar observation conditions but in seismically unperturbed periods (no earthquakes with ML≥5) that will be also presented.

  8. Infrasound Generation from the HH Seismic Hammer.

    SciTech Connect

    Jones, Kyle Richard

    2014-10-01

    The HH Seismic hammer is a large, "weight-drop" source for active source seismic experiments. This system provides a repetitive source that can be stacked for subsurface imaging and exploration studies. Although the seismic hammer was designed for seismological studies it was surmised that it might produce energy in the infrasonic frequency range due to the ground motion generated by the 13 metric ton drop mass. This study demonstrates that the seismic hammer generates a consistent acoustic source that could be used for in-situ sensor characterization, array evaluation and surface-air coupling studies for source characterization.

  9. The Community Seismic Network and Quake-Catcher Network: Monitoring building response to earthquakes through community instrumentation

    NASA Astrophysics Data System (ADS)

    Cheng, M.; Kohler, M. D.; Heaton, T. H.; Clayton, R. W.; Chandy, M.; Cochran, E.; Lawrence, J. F.

    2013-12-01

    The Community Seismic Network (CSN) and Quake-Catcher Network (QCN) are dense networks of low-cost ($50) accelerometers that are deployed by community volunteers in their homes in California. In addition, many accelerometers are installed in public spaces associated with civic services, publicly-operated utilities, university campuses, and high-rise buildings. Both CSN and QCN consist of observation-based structural monitoring which is carried out using records from one to tens of stations in a single building. We have deployed about 150 accelerometers in a number of buildings ranging between five and 23 stories in the Los Angeles region. In addition to a USB-connected device which connects to the host's computer, we have developed a stand-alone sensor-plug-computer device that directly connects to the internet via Ethernet or WiFi. In the case of CSN, the sensors report data to the Google App Engine cloud computing service consisting of data centers geographically distributed across the continent. This robust infrastructure provides parallelism and redundancy during times of disaster that could affect hardware. The QCN sensors, however, are connected to netbooks with continuous data streaming in real-time via the distributed computing Berkeley Open Infrastructure for Network Computing software program to a server at Stanford University. In both networks, continuous and triggered data streams use a STA/LTA scheme to determine the occurrence of significant ground accelerations. Waveform data, as well as derived parameters such as peak ground acceleration, are then sent to the associated archives. Visualization models of the instrumented buildings' dynamic linear response have been constructed using Google SketchUp and MATLAB. When data are available from a limited number of accelerometers installed in high rises, the buildings are represented as simple shear beam or prismatic Timoshenko beam models with soil-structure interaction. Small-magnitude earthquake records

  10. Use of geospatial information and in situ monitoring data for seismic hazard assessment in Vrancea area, Romania

    NASA Astrophysics Data System (ADS)

    Zoran, M.; Mateciuc, D.

    2009-04-01

    Remote sensing and geospatial information tools and techniques, including numerical modeling, have advanced considerably in recent years, enabling a greater understanding of the Earth as a complex system of geophysical phenomena. The information derived from such systems and analyses are beginning to make their way into operational use by decision makers through a number of information products and decision-support capabilities that inform community based mitigation, preparedness, and/or relief and recovery activities. Space-based geodetic measurements of the solid Earth with the Global Positioning System in synergy with ground-based seismological measurements, interferometric synthetic aperture radar data, high-resolution digital elevation models as well imaging spectroscopy (e.g. using ASTER, MODIS and Hyperion data) are contributing significantly to seismic hazard risk assessment. Space-time anomalies of Earth's emitted radiation (radon in underground water and soil and surface air , thermal infrared in spectral range measured from satellite months to weeks before the occurrence of earthquakes etc.), ionospheric and electromagnetic anomalies have been interpreted, by several authors, as pre-seismic signals. Mainly due to the subcrustal earthquakes located at the sharp bend of the Southeast Carpathians, Vrancea zone in Romania, placed at conjunction of four tectonic blocks which lie on the edge of the Eurasian plate is considered one of the most seismically active areas in Europe with high potential of seismic hazard. Multispectral and multitemporal satellite images (LANDSAT TM, ETM , ASTER, MODIS) over a period 1988-2008 have been analyzed for recognizing the continuity and regional relationships of active faults as well as for geologic and seismic hazard mapping. GPS measurements can serve as a reference to these results. In spite of providing the best constraints on the rate of strain accumulation on active faults (coseismic, postseismic, and interseismic

  11. 4D seismic monitoring of the miscible CO2 flood of Hall-Gurney Field, Kansas, U.S

    USGS Publications Warehouse

    Raef, A.E.; Miller, R.D.; Byrnes, A.P.; Harrison, W.E.

    2004-01-01

    A cost-effective, highly repeatable, 4D-optimized, single-pattern/patch seismic data-acquisition approach with several 3D data sets was used to evaluate the feasibility of imaging changes associated with the " water alternated with gas" (WAG) stage. By incorporating noninversion-based seismic-attribute analysis, the time and cost of processing and interpreting the data were reduced. A 24-ms-thick EOR-CO 2 injection interval-using an average instantaneous frequency attribute (AIF) was targeted. Changes in amplitude response related to decrease in velocity from pore-fluid replacement within this time interval were found to be lower relative to background values than in AIF analysis. Carefully color-balanced AIF-attribute maps established the overall area affected by the injected EOR-CO2.

  12. Wet Fault or Dry Fault? A Laboratory Approach to Remotely Monitor the Hydro-Mechanical State of a Discontinuity Using Controlled-Source Seismics

    NASA Astrophysics Data System (ADS)

    Place, Joachim; Blake, Oshaine; Faulkner, Daniel; Rietbrock, Andreas

    2014-11-01

    Stress variation and fluid migration occur in deformation zones, which are expected to affect seismic waves reflected off or propagating across such structures. We developed a basic experimental approach to monitor the mechanical coupling with respect to seismic coupling across a single discontinuity between a granite sample in contact with a steel platen. Piezoceramics located on the platen were used to both generate and record the P and S wave fields reflected off the discontinuity at normal incidence. This way, normal ( B n) and tangential ( B t) compliances were calculated using Schoenberg's linear slip theory (Schoenberg, J Acoust Soc Am 68:1516-1521, 1980) when the roughness, the effective pressure ( P eff, up to 200 MPa), and the nature of the filling (gas or water) vary. We observe that increasing the effective pressure decreases B n and B t, which is interpreted as the effect of the closure of the voids at the interface, permitting more seismic energy to be transmitted across the interface. Values of B n are significantly higher than those of B t at low P eff (<60-80 MPa) in dry conditions, and significantly drop under water-saturated conditions. The water filling the voids therefore helps to transmit the seismic energy of compressional waves across the interface. These results show that the assumption B n ≈ B t commonly found in some theoretical approaches does not always stand. The ratio B n/ B t actually reflects the type of saturating fluids and the effective pressure, in agreement with other experimental studies. However, we illustrate that only the relative variations of this ratio seem to be relevant, not its absolute value as suggested in previous studies. Consequently, the use of B n against B t plots may allow effective pressure variation and the nature of the pore fluid to be inferred. In this respect, this experimental approach at sample scale helps to pave the way for remotely monitoring in the field the hydro-mechanical state of deformation

  13. Volcano dome dynamics at Mount St. Helens: Deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets

    NASA Astrophysics Data System (ADS)

    Salzer, J. T.; Thelen, W. A.; James, M. R.; Walter, T. R.; Moran, S. C.; Denlinger, R. P.

    2015-12-01

    The morphology of a volcanic lava dome and its rate of change play key roles in the estimation of dome stability. While long term variations of dome morphology can be quantified using aerial remote sensing, changes over shorter time scales and smaller spatial scales are more difficult to determine. However, intermittent destabilization of the dome, in particular on flanks of the domes, can be significant. This study focuses on short term deformation associated with earthquakes and tremor at Mount St. Helens, observed over a 6 week period in the summer of 2006. We use Digital Image Correlation (DIC) to compute the displacement field between successive optical images acquired by multiple fixed cameras with clear views of the dome. The results of the these calculations are compared to the occurrence of seismic events. A systematic time-series DIC analysis of image pairs showed no sharp changes in the dome morphology during periods without seismic events. However, the results reveal that the steady dome growth at Mount St. Helens was interrupted by short term displacements reaching magnitudes on the order of a meter. These displacements are only observed in association with low frequency, large magnitude seismic events, followed by tremor with frequencies between 5 Hz and likely exceeding 30 Hz. For selected events that coincide with the timing of the acquisition of an accurate DEM of the crater floor, we reproject the displacement fields obtained from two cameras onto the topography. This enables 3D displacement vectors to be derived, showing that the co-seismic deformation is marked by subsidence of the dome in a segmented fashion, the central region displaying mainly vertical motion, while the displacements on the talus are more slope-parallel. The exact relationship between the recorded seismic energy and the observed deformation of the dome can not be resolved because the cameras were only sampling every 15 - 60 minutes. However, our analysis suggests that the

  14. Seismic ACROSS Transmitter Installed at Morimachi above the Subducting Philippine Sea Plate for the Test Monitoring of the Seismogenic Zone of Tokai Earthquake not yet to Occur

    NASA Astrophysics Data System (ADS)

    Kunitomo, T.; Kumazawa, M.; Masuda, T.; Morita, N.; Torii, T.; Ishikawa, Y.; Yoshikawa, S.; Katsumata, A.; Yoshida, Y.

    2008-12-01

    Here we report the first seismic monitoring system in active and constant operation for the wave propagation characteristics in tectonic region just above the subducting plate driving the coming catastrophic earthquakes. Developmental works of such a system (ACROSS; acronym for Accurately Controlled, Routinely Operated, Signal System) have been started in 1994 at Nagoya University and since 1996 also at TGC (Tono Geoscience Center) of JAEA promoted by Hyogoken Nanbu Earthquakes (1995 Jan.17, Mj=7.3). The ACROSS is a technology system including theory of signal and data processing based on the brand new concept of measurement methodology of Green function between a signal source and observation site. The works done for first generation system are reported at IWAM04 and in JAEA report (Kumazawa et al.,2007). The Meteorological Research Institute of JMA has started a project of test monitoring of Tokai area in 2004 in corporation with Shizuoka University to realize the practical use of the seismic ACROSS for earthquake prediction researches. The first target was set to Tokai Earthquake not yet to take place. The seismic ACROSS transmitter was designed so as to be appropriate for the sensitive monitoring of the deep active fault zone on the basis of the previous technology elements accumulated so far. The ground coupler (antenna) is a large steel-reinforced concrete block (over 20m3) installed in the basement rocks in order to preserve the stability. Eccentric moment of the rotary transmitter is 82 kgm at maximum, 10 times larger than that of the first generation. Carrier frequency of FM signal for practical use can be from 3.5 to 15 Hz, and the signal phase is accurately controlled by a motor with vector inverter synchronized with GPS clock with a precision of 10-4 radian or better. By referring to the existing structure model in this area (Iidaka et al., 2003), the site of the transmitting station was chosen at Morimachi so as to be appropriate for detecting the

  15. Real time electromagnetic monitoring system used for short-term earthquakes forecast related to the seismic-active Vrancea zone

    NASA Astrophysics Data System (ADS)

    Stanica, Dumitru; Armand Stanica, Dragos

    2016-04-01

    The existence of the pre-seismic electromagnetic signals related to the earthquakes is still under scientific debate and requires new reliable information about their possible inter-relationship. In this paper, to obtain new insights into the seismic active Vrancea zone (Romania), a 3-D magnetotelluric imaging has been used to strengthen the connection between the geodynamic model and a possible generation mechanism of the intermediate depth earthquakes. Consequently, it is considered that before an earthquake initiation, due to the torsion effect, a high stress reached inside the seismogenic volume that may generates dehydration and rupture processes of the rocks, associated with the fluid migration through the lithospheric faults system, what leads to the resistivity changes. These changes have been investigated by using ULF electromagnetic data recorded in real time at the Geodynamic Observatory Provita de Sus (GOPS), placed on the Carpathian Electrical Conductivity Anomaly (CECA) at about 100km far from the seismic active Vrancea zone. The daily mean distribution of the normalized function Bzn(f) = Bz(f)/Bperp(f) (where: Bz is vertical component of the geomagnetic field; Bperp is geomagnetic component perpendicular to strike; f is frequency in Hz) and its standard deviation are performed by using a FFT band-pass filter analysis in the ULF range 0.001Hz to 0.0083Hz, for which a 2-D geoelectrical structure under GOPS has been identified. To provide reliable information in anticipating the likelihood occurrence of an earthquake of Mw higher than 4, a statistical analysis based on standardized random variable equation has been used to identify the anomalous intervals on the new time series (Bzn*) carried out in a span of three years (2013-2015). The final conclusion is that the Bzn* shows a significant anomalous effect some days (weeks) before an impending earthquake and it should be used for short-term earthquakes forecast.

  16. Annual Hanford seismic report -- fiscal year 1996

    SciTech Connect

    Hartshorn, D.C.; Reidel, S.P.

    1996-12-01

    Seismic monitoring (SM) at the Hanford Site was established in 1969 by the US Geological Survey (USGS) under a contract with the US Atomic Energy Commission. Since 1980, the program has been managed by several contractors under the US Department of Energy (USDOE). Effective October 1, 1996, the Seismic Monitoring workscope, personnel, and associated contracts were transferred to the USDOE Pacific Northwest National Laboratory (PNNL). SM is tasked to provide an uninterrupted collection and archives of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) located on and encircling the Hanford Site. SM is also tasked to locate and identify sources of seismic activity and monitor changes in the historical pattern of seismic activity at the Hanford Site. The data compiled are used by SM, Waste Management, and engineering activities at the Hanford Site to evaluate seismic hazards and seismic design for the Site.

  17. The Use of Explosion Aftershock Probabilities for Planning and Deployment of Seismic Aftershock Monitoring System for an On-site Inspection

    NASA Astrophysics Data System (ADS)

    Labak, P.; Ford, S. R.; Sweeney, J. J.; Smith, A. T.; Spivak, A.

    2011-12-01

    One of four elements of CTBT verification regime is On-site inspection (OSI). Since the sole purpose of an OSI shall be to clarify whether a nuclear weapon test explosion or any other nuclear explosion has been carried out, inspection activities can be conducted and techniques used in order to collect facts to support findings provided in inspection reports. Passive seismological monitoring, realized by the seismic aftershock monitoring (SAMS) is one of the treaty allowed techniques during an OSI. Effective planning and deployment of SAMS during the early stages of an OSI is required due to the nature of possible events recorded and due to the treaty related constrains on size of inspection area, size of inspection team and length of an inspection. A method, which may help in planning the SAMS deployment is presented. An estimate of aftershock activity due to a theoretical underground nuclear explosion is produced using a simple aftershock rate model (Ford and Walter, 2010). The model is developed with data from the Nevada Test Site and Semipalatinsk Test Site, which we take to represent soft- and hard-rock testing environments, respectively. Estimates of expected magnitude and number of aftershocks are calculated using the models for different testing and inspection scenarios. These estimates can help to plan the SAMS deployment for an OSI by giving a probabilistic assessment of potential aftershocks in the Inspection Area (IA). The aftershock assessment combined with an estimate of the background seismicity in the IA and an empirically-derived map of threshold magnitude for the SAMS network could aid the OSI team in reporting. We tested the hard-rock model to a scenario similar to the 2008 Integrated Field Exercise 2008 deployment in Kazakhstan and produce an estimate of possible recorded aftershock activity.

  18. Features of seismicity of the Euro-Arctic region

    NASA Astrophysics Data System (ADS)

    Rogozhin, E. A.; Antonovskaya, G. N.; Kapustian, N. K.; Fedorenko, I. V.

    2016-04-01

    New results from seismic monitoring in the Euro-Arctic region, including the seismicity of Gakkel Ridge and the Barents-Kara Sea shelf, are presented. The data used were obtained from the Arkhan-gelsk seismic network. The role of island-based seismic stations, in particular, those in Franz Josef Land, in the monitoring network is discussed. The possibility of specifying the nature of seismicity by waveform spectral-temporal analysis, even in the case of a single station, is considered.

  19. Precise Monitoring of Non-volcanic Low-frequency Tremors using Vertical Seismic Array: The case of Tokai Area, Southwest Japan

    NASA Astrophysics Data System (ADS)

    Takeda, N.; Imanishi, K.; Koizumi, N.

    2010-12-01

    Non-volcanic low frequency tremor (LFTs) and short-term slow slip events have been found in various subduction zones and the strike-slip San Andreas Fault during the last decade. Previous studies suggest that these slow events occur within the quasi-stable frictional regime downdip of the shallower seismogenic-locked zone. Therefore, a detailed real-time monitoring of these phenomena is one of the useful ways for forecasting the next great earthquakes. In 2007, Geological Survey of Japan, AIST has started an integrated borehole observation in southwest Japan for forecasting the anticipated Tokai, Tonankai and Nankai megathrust earthquakes. Each observatory has three boreholes with different depths (about 30 m, 200 m and 600 m), in which we installed high-sensitivity seismometers at the bottom of every borehole. On the basis of a semblance analysis using this vertical seismic array data, we developed a monitoring system of the LFTs and showed a dramatic improvement of the LFTs detection (Takeda et al., 2009). This study focuses on the analysis of LFTs in Tokai area using vertical seismic array data. The major LFTs episode in the area last for days to week and occur repeatedly every six months. We have one observatory above the middle of the Tokai LFTs zone, where we started the vertical array observation in June 2008. We calculated a semblance for a range of values in apparent velocity space using one-minute long moving windows. It is easy to discriminate seismic signals associated with the LFTs from cultural noise by both the sign and value of the best apparent velocity for that particular window. We calculated total duration of the LFTs activity for each hour by counting the time that the semblance value of the best apparent velocity exceeds a specific threshold. The two year’s time-duration plot suggests that our semblance method detected about ten times in duration than that by the envelope correlation method (ECM). During each major episode, the time

  20. Designing a low-cost effective network for monitoring large scale regional seismicity in a soft-soil region (Alsace, France)

    NASA Astrophysics Data System (ADS)

    Bès de Berc, M.; Doubre, C.; Wodling, H.; Jund, H.; Hernandez, A.; Blumentritt, H.

    2015-12-01

    The Seismological Observatory of the North-East of France (ObSNEF) is developing its monitoring network within the framework of several projects. Among these project, RESIF (Réseau sismologique et géodésique français) allows the instrumentation of broad-band seismic stations, separated by 50-100 km. With the recent and future development of geothermal industrial projects in the Alsace region, the ObSNEF is responsible for designing, building and operating a dense regional seismic network in order to detect and localize earthquakes with both a completeness magnitude of 1.5 and no clipping for M6.0. The realization of the project has to be done prior to the summer 2016Several complex technical and financial constraints constitute such a projet. First, most of the Alsace Région (150x150 km2), particularly the whole Upper Rhine Graben, is a soft-soil plain where seismic signals are dominated by a high frequency noise level. Second, all the signals have to be transmitted in near real-time. And finally, the total cost of the project must not exceed $450,000.Regarding the noise level in Alsace, in order to make a reduction of 40 dB for frequencies above 1Hz, we program to instrument into 50m deep well with post-hole sensor for 5 stations out of 8 plane new stations. The 3 remaining would be located on bedrock along the Vosges piedmont. In order to be sensitive to low-magnitude regional events, we plan to install a low-noise short-period post-hole velocimeter. In order to avoid saturation for high potentiel local events (M6.0 at 10km), this velocimeter will be coupled with a surface strong-motion sensor. Regarding the connectivity, these stations will have no wired network, which reduces linking costs and delays. We will therefore use solar panels and a 3G/GPRS network. The infrastructure will be minimal and reduced to an outdoor box on a secured parcel of land. In addition to the data-logger, we will use a 12V ruggedized computer, hosting a seed-link server for near

  1. Martian seismicity

    NASA Technical Reports Server (NTRS)

    Phillips, Roger J.; Grimm, Robert E.

    1991-01-01

    The design and ultimate success of network seismology experiments on Mars depends on the present level of Martian seismicity. Volcanic and tectonic landforms observed from imaging experiments show that Mars must have been a seismically active planet in the past and there is no reason to discount the notion that Mars is seismically active today but at a lower level of activity. Models are explored for present day Mars seismicity. Depending on the sensitivity and geometry of a seismic network and the attenuation and scattering properties of the interior, it appears that a reasonable number of Martian seismic events would be detected over the period of a decade. The thermoelastic cooling mechanism as estimated is surely a lower bound, and a more refined estimate would take into account specifically the regional cooling of Tharsis and lead to a higher frequency of seismic events.

  2. Passive Seismic Reflectivity Imaging with Ocean-Bottom Cable Data

    NASA Astrophysics Data System (ADS)

    Hohl, D.; Mateeva, A.

    2005-12-01

    The idea of imaging the subsurface reflectivity distribution by correlating long traces of seismic ``noise'' (i.e. seismic data recorded without active sources) goes back more than 30 years [1]. To this day, passive seismic reflectivity imaging has not been exploited for business use in the E&P industry. The conditions for successful passive seismic reflection imaging have greatly improved over the past few years, and the prize of cheap continuous sourceless seismic imaging and possibly monitoring is still large. Nearly unlimited quantities of very high quality passive noise data are now available from permanent 4C ocean bottom cable (OBC) installations. In the present contribution, we report our initial results for single-line (2D) OBC data collected in the North Sea and GOM. The OBCs used for the experiment are of length 6-10 km with 4C receivers spaced 50 m apart. They are deployed in both shallow and deep water over large hydrocarbon reservoirs. Passive noise data were recorded for 8-24 h periods, sometimes several times, and months apart. In the analysis presented here only the hydrophone records are used, and the data from all recording periods are used together to produce a single 2D migrated reflectivity section. We observe that environmental noise (e.g. boat and rig activity) play an important role for imaging and usually requires pre-migration seismic processing steps to filter out unwanted signals. At the core of our image generation and processing sequence is the crosscorrelation of noise trace pairs and subsequent prestack time migration [1] with a velocity model established for the active-source OBC data processing. We compute 4 sec of lag time to either side of t=0. After removing unwanted signals (e.g. seafloor interface waves) from these ``virtual shot gathers'' one can clearly detect the linear-moveout direct water wave with velocity 1500 m/s, and a linear interface wave with velocity 2000 m/s. Other ``events'' with moveout are visible, but the

  3. Albuquerque Basin seismic network

    USGS Publications Warehouse

    Jaksha, Lawrence H.; Locke, Jerry; Thompson, J.B.; Garcia, Alvin

    1977-01-01

    The U.S. Geological Survey has recently completed the installation of a seismic network around the Albuquerque Basin in New Mexico. The network consists of two seismometer arrays, a thirteen-station array monitoring an area of approximately 28,000 km 2 and an eight-element array monitoring the area immediately adjacent to the Albuquerque Seismological Laboratory. This report describes the instrumentation deployed in the network.

  4. Multi-disciplinary monitoring of the Hutubi underground natural gas storage

    NASA Astrophysics Data System (ADS)

    Wang, B.

    2015-12-01

    Underground natural Gas Storage (UGS) can balance the gas demand and supply through injecting gas into or withdraw gas from the subsurface rock formation. UGS has been wildly established all over the world to face the complicated international energy system. In 2013, the Hutubi underground natural gas storage was put into production, which was one of the largest UGS in China. In the Hutubi UGS, the pressurized natural gas is injected into and extracted from an obsolete gas reservoir during summer and winter time, respectively. The repeatable in and out going high pressure gas may change the stress state and material properties of the underground rock formation, which may in turn cause surface deformation and alter the seismic hazard in this region. To understand the physical process of the periodic loading and unloading, we established a multi-disciplinary monitoring system composed of a geodetic network, a seismic network, and an active source monitoring system. The position and level of 13 spots around and above the UGS area are measured every three to six months with Global Position System (GPS) and short base-line leveling. More than 30 portable broad band three component seismic stations were deployed in study area to continuously monitor the background and possible triggered seismicity. These seismic stations together with a 12000 in3 airgun source, are also used to monitor the seismic velocity change associated with the gas injection and extraction. Preliminary results indicate that seismic velocity change correlates well with the injection pressure; seismicity decays with the lapse time after the startup of Hutubi UGS; small but detectable surface deformation associated with the gas activities is observed.

  5. Landslide seismic magnitude

    NASA Astrophysics Data System (ADS)

    Lin, C. H.; Jan, J. C.; Pu, H. C.; Tu, Y.; Chen, C. C.; Wu, Y. M.

    2015-11-01

    Landslides have become one of the most deadly natural disasters on earth, not only due to a significant increase in extreme climate change caused by global warming, but also rapid economic development in topographic relief areas. How to detect landslides using a real-time system has become an important question for reducing possible landslide impacts on human society. However, traditional detection of landslides, either through direct surveys in the field or remote sensing images obtained via aircraft or satellites, is highly time consuming. Here we analyze very long period seismic signals (20-50 s) generated by large landslides such as Typhoon Morakot, which passed though Taiwan in August 2009. In addition to successfully locating 109 large landslides, we define landslide seismic magnitude based on an empirical formula: Lm = log ⁡ (A) + 0.55 log ⁡ (Δ) + 2.44, where A is the maximum displacement (μm) recorded at one seismic station and Δ is its distance (km) from the landslide. We conclude that both the location and seismic magnitude of large landslides can be rapidly estimated from broadband seismic networks for both academic and applied purposes, similar to earthquake monitoring. We suggest a real-time algorithm be set up for routine monitoring of landslides in places where they pose a frequent threat.

  6. Continuous and discrete monitoring of groundwater chemistry at some groundwater sites in the Etna volcano, during the recent seismic and volcanic crises (2001-2002)

    NASA Astrophysics Data System (ADS)

    Galli, G.; Cinti, D.; Condarelli, D.; Neri, M.; Pizzino, L.; Pongetti, F.; Quattrocchi, F.; Voltattorni, N.

    2003-04-01

    Starting from 1998 a Geochemical Monitoring System (GMS-2 prototype onward) was installed at the "Acqua Difesa" well (Belpasso town, 130 m deep) while another GMS-2 was installed in June 2001 at the "Acqua Currone" well (Paternò town, 120 m deep). Both stations are measuring (every 10 minutes): water temperature, pH, Eh, electrical conductivity, dissolved CO_2, air temperature and barometric pressure. Only at the "Acqua Currone well the dissolved 222Rn is measured every 6 hours and the static level is measured every 10 minutes too. At both stations an automatic sampler collects every three days two bottles, acidified and not, for further geochemical analyses. The automatically collected samples were analysed as regards the major elements and some minor and trace elements. Moreover some strategically positioned wells (Acqua Difesa, Monte Ilice, Acqua Currone, Pavone) have been monitored as regards the dissolved 222Rn starting from October 2002 just before, during and after the 2002 seismic and volcanic Etna crisis. We discuss the possible correlation between geochemical and hydrogeological anomalies mostly during the 2002 and also during the less energetic 2001 seismic and volcanic crises. In particular, for the 2002 crisis, we observed that, after a quiescent period for the Etna volcano (September 2001 - October 2002) during which the geochemical data at the two station remained more or less unchanged, very clear geochemical anomalies were recorded at the Acqua Currone. A first geochemical-hydrogeological anomaly starts from the early morning on September, 15, 2002 (2 meters uplift of the piezometric level), possibly related to a strong compressive event in the main aquifer: the water became hotter (2^oC), more acidic, more reducing, more saline (around 200 μS/cm higher with respect to the previous data) and showed a minor 222Rn content as well. After this first "fracturing/mixing episode", the static level decreased progressively of around 2 meters in two and a

  7. Leveraging Educational, Research and Facility Expertise to Improve Global Seismic Monitoring: Preparing a Guide on Sustainable Networks

    NASA Astrophysics Data System (ADS)

    Nybade, A.; Aster, R.; Beck, S.; Ekstrom, G.; Fischer, K.; Lerner-Lam, A.; Meltzer, A.; Sandvol, E.; Willemann, R. J.

    2008-12-01

    Building a sustainable earthquake monitoring system requires well-informed cooperation between commercial companies that manufacture components or deliver complete systems and the government or other agencies that will be responsible for operating them. Many nations or regions with significant earthquake hazard lack the financial, technical, and human resources to establish and sustain permanent observatory networks required to return the data needed for hazard mitigation. Government agencies may not be well- informed about the short-term and long-term challenges of managing technologically advanced monitoring systems, much less the details of how they are built and operated. On the relatively compressed time scale of disaster recovery efforts, it can be difficult to find a reliable, disinterested source of information, without which government agencies may be dependent on partial information. If system delivery fails to include sufficient development of indigenous expertise, the performance of local and regional networks may decline quickly, and even data collected during an early high-performance period may be degraded or lost. Drawing on unsurpassed educational capabilities of its members working in close cooperation with its facility staff, IRIS is well prepared to contribute to sustainability through a wide variety of training and service activities that further promote standards for network installation, data exchange protocols, and free and open access to data. Members of the Consortium and staff of its Core Programs together could write a guide on decisions about network design, installation and operation. The intended primary audience would be government officials seeking to understand system requirements, the acquisition and installation process, and the expertise needed operate a system. The guide would cover network design, procurement, set-up, data use and archiving. Chapters could include advice on network data processing, archiving data (including

  8. Seismic Ecology

    NASA Astrophysics Data System (ADS)

    Seleznev, V. S.; Soloviev, V. M.; Emanov, A. F.

    The paper is devoted to researches of influence of seismic actions for industrial and civil buildings and people. The seismic actions bring influence directly on the people (vibration actions, force shocks at earthquakes) or indirectly through various build- ings and the constructions and can be strong (be felt by people) and weak (be fixed by sensing devices). The great number of work is devoted to influence of violent seismic actions (first of all of earthquakes) on people and various constructions. This work is devoted to study weak, but long seismic actions on various buildings and people. There is a need to take into account seismic oscillations, acting on the territory, at construction of various buildings on urbanized territories. Essential influence, except for violent earthquakes, man-caused seismic actions: the explosions, seismic noise, emitted by plant facilities and moving transport, radiation from high-rise buildings and constructions under action of a wind, etc. can exert. Materials on increase of man- caused seismicity in a number of regions in Russia, which earlier were not seismic, are presented in the paper. Along with maps of seismic microzoning maps to be built indicating a variation of amplitude spectra of seismic noise within day, months, years. The presence of an information about amplitudes and frequencies of oscillations from possible earthquakes and man-caused oscillations in concrete regions allows carry- ing out soundly designing and construction of industrial and civil housing projects. The construction of buildings even in not seismically dangerous regions, which have one from resonance frequencies coincident on magnitude to frequency of oscillations, emitted in this place by man-caused objects, can end in failure of these buildings and heaviest consequences for the people. The practical examples of detail of engineering- seismological investigation of large industrial and civil housing projects of Siberia territory (hydro power

  9. SEISMIC SIMULATIONS USING PARALLEL COMPUTING AND THREE-DIMENSIONAL EARTH MODELS TO IMPROVE NUCLEAR EXPLOSION PHENOMENOLOGY AND MONITORING

    SciTech Connect

    Rodgers, A; Matzel, E; Pasyanos, M; Petersson, A; Sjogreen, B; Bono, C; Vorobiev, O; Antoun, T; Walter, W; Myers, S; Lomov, I

    2008-07-07

    , we are modeling non-linear near-source shock wave propagation with GEODYN, an Eulerian Godunov finite-difference code (Antoun et al., 2001). This code accounts for shock wave propagation and a variety of effects including cavity formation, rock fracture and plastic deformation. We are exploring the coupling of GEODYN to WPP to propagate motions from the near-source (non-linear) region to the (linear anelastic) region where seismic observations are made at local, regional and teleseismic distances. This effort has just begun and we show preliminary results in this paper (with more to follow in our poster). These simulation tools are supported by massively parallel computers operated by Livermore Computing.

  10. Seismicity in Northern Germany

    NASA Astrophysics Data System (ADS)

    Bischoff, Monika; Gestermann, Nicolai; Plenefisch, Thomas; Bönnemann, Christian

    2013-04-01

    Northern Germany is a region of low tectonic activity, where only few and low-magnitude earthquakes occur. The driving tectonic processes are not well-understood up to now. In addition, seismic events during the last decade concentrated at the borders of the natural gas fields. The source depths of these events are shallow and in the depth range of the gas reservoirs. Based on these observations a causal relationship between seismicity near gas fields and the gas production is likely. The strongest of these earthquake had a magnitude of 4.5 and occurred near Rotenburg in 2004. Also smaller seismic events were considerably felt by the public and stimulated the discussion on the underlying processes. The latest seismic event occurred near Langwedel on 22nd November 2012 and had a magnitude of 2.8. Understanding the causes of the seismicity in Northern Germany is crucial for a thorough evaluation. Therefore the Seismological Service of Lower Saxony (NED) was established at the State Office for Mining, Energy and Geology (LBEG) of Lower Saxony in January 2013. Its main task is the monitoring and evaluation of the seismicity in Lower Saxony and adjacent areas. Scientific and technical questions are addressed in close cooperation with the Seismological Central Observatory (SZO) at the Federal Institute for Geosciences and Natural Resources (BGR). The seismological situation of Northern Germany will be presented. Possible causes of seismicity are introduced. Rare seismic events at greater depths are distributed over the whole region and probably are purely tectonic whereas events in the vicinity of natural gas fields are probably related to gas production. Improving the detection threshold of seismic events in Northern Germany is necessary for providing a better statistical basis for further analyses answering these questions. As a first step the existing seismic network will be densified over the next few years. The first borehole station was installed near Rethem by BGR

  11. Seismic instrumentation plan for the Hawaiian Volcano Observatory

    USGS Publications Warehouse

    Thelen, Weston A.

    2014-01-01

    The installation of new seismic stations is only the first part of building a volcanic early warning capability for seismicity in the State of Hawaii. Additional personnel will likely be required to study the volcanic processes at work under each volcano, analyze the current seismic activity at a level sufficient for early warning, build new tools for monitoring, maintain seismic computing resources, and maintain the new seismic stations.

  12. The effect of light-activation sources on tooth bleaching

    PubMed Central

    Baroudi, Kusai; Hassan, Nadia Aly

    2014-01-01

    Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching. PMID:25298598

  13. Validating induced seismicity forecast models—Induced Seismicity Test Bench

    NASA Astrophysics Data System (ADS)

    Király-Proag, Eszter; Zechar, J. Douglas; Gischig, Valentin; Wiemer, Stefan; Karvounis, Dimitrios; Doetsch, Joseph

    2016-08-01

    Induced earthquakes often accompany fluid injection, and the seismic hazard they pose threatens various underground engineering projects. Models to monitor and control induced seismic hazard with traffic light systems should be probabilistic, forward-looking, and updated as new data arrive. In this study, we propose an Induced Seismicity Test Bench to test and rank such models; this test bench can be used for model development, model selection, and ensemble model building. We apply the test bench to data from the Basel 2006 and Soultz-sous-Forêts 2004 geothermal stimulation projects, and we assess forecasts from two models: Shapiro and Smoothed Seismicity (SaSS) and Hydraulics and Seismics (HySei). These models incorporate a different mix of physics-based elements and stochastic representation of the induced sequences. Our results show that neither model is fully superior to the other. Generally, HySei forecasts the seismicity rate better after shut-in but is only mediocre at forecasting the spatial distribution. On the other hand, SaSS forecasts the spatial distribution better and gives better seismicity rate estimates before shut-in. The shut-in phase is a difficult moment for both models in both reservoirs: the models tend to underpredict the seismicity rate around, and shortly after, shut-in.

  14. Monitoring fin whale (Balaenoptera physalus) acoustic presence by means of a low frequency seismic hydrophone in Western Ionian Sea, EMSO site.

    NASA Astrophysics Data System (ADS)

    Sciacca, Virginia; Caruso, Francesco; Chierici, Francesco; De Domenico, Emilio; Embriaco, Davide; Favali, Paolo; Giovanetti, Gabriele; Larosa, Giuseppina; Pavan, Gianni; Pellegrino, Carmelo; Pulvirenti, Sara; Riccobene, Giorgio; Simeone, Francesco; Viola, Salvatore; Beranzoli, Laura; Marinaro, Giuditta

    2015-04-01

    In 2012, the NEMO-SN1 multidisciplinary seafloor platform was deployed in the Gulf of Catania at a depth of 2100 m. By using the low bandwidth seismic hydrophone SMID DT405D (1Hz monitored for the first time, over a yearlong campaign, fin whales (Balaenoptera physalus) acoustic activity in the area. The presence of a genetically isolated population of fin whales has been confirmed in recent years in highly productive areas of the Mediterranean Sea. The species acoustic activity has also been monitored in the past within the Western Mediterranean. Despite this, still very little is known about the routes the population follows seasonally throughout the whole basin and, particularly, in the Ionian area. The most common vocalizations attributed to this population are known as "20Hz pulses" and they are grouped in two main types of calls: type "A", downsweep (17Hz

  15. Seismic seiches

    USGS Publications Warehouse

    McGarr, Arthur; Gupta, Harsh K.

    2011-01-01

    Seismic seiche is a term first used by Kvale (1955) to discuss oscillations of lake levels in Norway and England caused by the Assam earthquake of August 15, 1950. This definition has since been generalized to apply to standing waves set up in closed, or partially closed, bodies of water including rivers, shipping channels, lakes, swimming pools and tanks due to the passage of seismic waves from an earthquake.

  16. Design of a potential long-term test of gas production from a hydrate deposit at the PBU-L106 site in North Slope, Alaska: Geomechanical system response and seismic monitoring

    NASA Astrophysics Data System (ADS)

    Chiaramonte, L.; Kowalsky, M. B.; Rutqvist, J.; Moridis, G. J.

    2009-12-01

    In an effort to optimize the design of a potential long-term production test at the PBU-L106 site in North Slope, Alaska, we have developed a coupled modeling framework that includes the simulation of (1) large-scale production at the test site, (2) the corresponding geomechanical changes in the system caused by production, and (3) time-lapse geophysical (seismic) surveys. The long-term test is to be conducted within the deposit of the C-layer, which extends from a depth of 2226 to 2374 ft, and is characterized by two hydrate-bearing strata separated by a 30 ft shale interlayer. In this study we examine the expected geomechanical response of the permafrost-associated hydrate deposit (C-Layer) at the PBU L106 site during depressurization-induced production, and assess the potential for monitoring the system response with seismic measurements. Gas hydrates increase the strength of the sediments (often unconsolidated) they impregnate. Thus hydrate disassociation in the course of gas production could potentially affect the geomechanical stability of such deposits, leading to sediment failure and potentially affecting wellbore stability and integrity at the production site and/or at neighboring conventional production facilities. For the geomechanical analysis we use a coupled hydraulic, thermodynamic and geomechanical model (TOUGH+HYDRATE+FLAC3D, T+H+F for short) simulating production from a single vertical well at the center of an infinite-acting hydrate deposit. We investigate the geomechanical stability of the C-Layer, well stability and possible interference (due to production) with pre-existing wells in the vicinity, as well as the system sensitivity to important parameters (saturation, permeability, porosity and heterogeneity). The time-lapse seismic surveys are simulated using a finite-difference elastic wave propagation model that is linked to the T+H+F code. The seismic properties, such as the elastic and shear moduli, are a function of the simulated time- and

  17. Seismic bearing

    NASA Astrophysics Data System (ADS)

    Power, Dennis

    2009-05-01

    Textron Systems (Textron) has been using geophones for target detection for many years. This sensing capability was utilized for detection and classification purposes only. Recently Textron has been evaluating multiaxis geophones to calculate bearings and track targets more specifically personnel. This capability will not only aid the system in locating personnel in bearing space or cartesian space but also enhance detection and reduce false alarms. Textron has been involved in the testing and evaluation of several sensors at multiple sites. One of the challenges of calculating seismic bearing is an adequate signal to noise ratio. The sensor signal to noise ratio is a function of sensor coupling to the ground, seismic propagation and range to target. The goals of testing at multiple sites are to gain a good understanding of the maximum and minimum ranges for bearing and detection and to exploit that information to tailor sensor system emplacement to achieve desired performance. Test sites include 10A Site Devens, MA, McKenna Airfield Ft. Benning, GA and Yuma Proving Ground Yuma, AZ. Geophone sensors evaluated include a 28 Hz triax spike, a 15 Hz triax spike and a hybrid triax spike consisting of a 10 Hz vertical geophone and two 28 Hz horizontal geophones. The algorithm uses raw seismic data to calculate the bearings. All evaluated sensors have triaxial geophone configuration mounted to a spike housing/fixture. The suite of sensors also compares various types of geophones to evaluate benefits in lower bandwidth. The data products of these tests include raw geophone signals, seismic features, seismic bearings, seismic detection and GPS position truth data. The analyses produce Probability of Detection vs range, bearing accuracy vs range, and seismic feature level vs range. These analysis products are compared across test sites and sensor types.

  18. Seismic Studies

    SciTech Connect

    R. Quittmeyer

    2006-09-25

    This technical work plan (TWP) describes the efforts to develop and confirm seismic ground motion inputs used for preclosure design and probabilistic safety 'analyses and to assess the postclosure performance of a repository at Yucca Mountain, Nevada. As part of the effort to develop seismic inputs, the TWP covers testing and analyses that provide the technical basis for inputs to the seismic ground-motion site-response model. The TWP also addresses preparation of a seismic methodology report for submission to the U.S. Nuclear Regulatory Commission (NRC). The activities discussed in this TWP are planned for fiscal years (FY) 2006 through 2008. Some of the work enhances the technical basis for previously developed seismic inputs and reduces uncertainties and conservatism used in previous analyses and modeling. These activities support the defense of a license application. Other activities provide new results that will support development of the preclosure, safety case; these results directly support and will be included in the license application. Table 1 indicates which activities support the license application and which support licensing defense. The activities are listed in Section 1.2; the methods and approaches used to implement them are discussed in more detail in Section 2.2. Technical and performance objectives of this work scope are: (1) For annual ground motion exceedance probabilities appropriate for preclosure design analyses, provide site-specific seismic design acceleration response spectra for a range of damping values; strain-compatible soil properties; peak motions, strains, and curvatures as a function of depth; and time histories (acceleration, velocity, and displacement). Provide seismic design inputs for the waste emplacement level and for surface sites. Results should be consistent with the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain and reflect, as appropriate, available knowledge on the limits to extreme ground motion at

  19. Functional performance requirements for seismic network upgrade

    SciTech Connect

    Lee, R.C.

    1991-08-18

    The SRL seismic network, established in 1976, was developed to monitor site and regional seismic activity that may have any potential to impact the safety or reduce containment capability of existing and planned structures and systems at the SRS, report seismic activity that may be relevant to emergency preparedness, including rapid assessments of earthquake location and magnitude, and estimates of potential on-site and off-site damage to facilities and lifelines for mitigation measures. All of these tasks require SRL seismologists to provide rapid analysis of large amounts of seismic data. The current seismic network upgrade, the subject of this Functional Performance Requirements Document, is necessary to improve system reliability and resolution. The upgrade provides equipment for the analysis of the network seismic data and replacement of old out-dated equipment. The digital network upgrade is configured for field station and laboratory digital processing systems. The upgrade consists of the purchase and installation of seismic sensors,, data telemetry digital upgrades, a dedicated Seismic Data Processing (SDP) system (already in procurement stage), and a Seismic Signal Analysis (SSA) system. The field stations and telephone telemetry upgrades include equipment necessary for three remote station upgrades including seismic amplifiers, voltage controlled oscillators, pulse calibrators, weather protection (including lightning protection) systems, seismometers, seismic amplifiers, and miscellaneous other parts. The central receiving and recording station upgrades will include discriminators, helicopter amplifier, omega timing system, strong motion instruments, wide-band velocity sensors, and other miscellaneous equipment.

  20. Seismic Tomography.

    ERIC Educational Resources Information Center

    Anderson, Don L.; Dziewonski, Adam M.

    1984-01-01

    Describes how seismic tomography is used to analyze the waves produced by earthquakes. The information obtained from the procedure can then be used to map the earth's mantle in three dimensions. The resulting maps are then studied to determine such information as the convective flow that propels the crustal plates. (JN)

  1. Seismic Symphonies

    NASA Astrophysics Data System (ADS)

    Strinna, Elisa; Ferrari, Graziano

    2015-04-01

    The project started in 2008 as a sound installation, a collaboration between an artist, a barrel organ builder and a seismologist. The work differs from other attempts of sound transposition of seismic records. In this case seismic frequencies are not converted automatically into the "sound of the earthquake." However, it has been studied a musical translation system that, based on the organ tonal scale, generates a totally unexpected sequence of sounds which is intended to evoke the emotions aroused by the earthquake. The symphonies proposed in the project have somewhat peculiar origins: they in fact come to life from the translation of graphic tracks into a sound track. The graphic tracks in question are made up by copies of seismograms recorded during some earthquakes that have taken place around the world. Seismograms are translated into music by a sculpture-instrument, half a seismograph and half a barrel organ. The organ plays through holes practiced on paper. Adapting the documents to the instrument score, holes have been drilled on the waves' peaks. The organ covers about three tonal scales, starting from heavy and deep sounds it reaches up to high and jarring notes. The translation of the seismic records is based on a criterion that does match the highest sounds to larger amplitudes with lower ones to minors. Translating the seismogram in the organ score, the larger the amplitude of recorded waves, the more the seismogram covers the full tonal scale played by the barrel organ and the notes arouse an intense emotional response in the listener. Elisa Strinna's Seismic Symphonies installation becomes an unprecedented tool for emotional involvement, through which can be revived the memory of the greatest disasters of over a century of seismic history of the Earth. A bridge between art and science. Seismic Symphonies is also a symbolic inversion: the instrument of the organ is most commonly used in churches, and its sounds are derived from the heavens and

  2. A new seismic discriminant for earthquakes and explosions

    NASA Astrophysics Data System (ADS)

    Woods, Bradley B.; Helmberger, Donald V.

    With the spread of nuclear weapons technology, more regions of the world need to be monitored in order to verify nuclear nonproliferation and limited test-ban treaties. Seismic monitoring is the primary means to remotely sense contained underground explosions “Bolt, 1976; Dahlman and Israelson, 1977”. Both underground explosions and earthquakes generate seismic energy, which propagates through the Earth as elastic waves. The crux of the verification problem is to differentiate between the seismic signatures of explosions and earthquakes. Such identification is most difficult in countries with seismically active areas, where bombs might be detonated to blend in with the region's natural seismicity.

  3. Monitoring

    DOEpatents

    Orr, Christopher Henry; Luff, Craig Janson; Dockray, Thomas; Macarthur, Duncan Whittemore

    2004-11-23

    The invention provides apparatus and methods which facilitate movement of an instrument relative to an item or location being monitored and/or the item or location relative to the instrument, whilst successfully excluding extraneous ions from the detection location. Thus, ions generated by emissions from the item or location can successfully be monitored during movement. The technique employs sealing to exclude such ions, for instance, through an electro-field which attracts and discharges the ions prior to their entering the detecting location and/or using a magnetic field configured to repel the ions away from the detecting location.

  4. Near-surface Fun with Seismic Data

    NASA Astrophysics Data System (ADS)

    Clapp, M.

    2015-12-01

    What is happening in the near-surface often has a direct effect on human activity. Seismic exploration has routinely targeted geology at depths of kilometers to tens of kilometers. However, these techniques can be applied to answer questions about shallower targets. Several recent experiments demonstrate seismic applicability to near-surface problems. One example is passive seismic monitoring using ambient noise to identify shallow changes and potential hazards in a producing hydrocarbon field. Another example is the use of seismic reflection data from within the water column to determine layering caused by temperature and salinity differences in depth. A third example is identifying historical elevation changes along coast lines using seismic reflection data. These examples show that exploration seismic methods can be effectively used for a variety of near-surface applications.

  5. New seismic study begins in Puerto Rico

    USGS Publications Warehouse

    Tarr, A.C.

    1974-01-01

    A new seismological project is now underway in Puerto Rico to provide information needed for accurate assessment of the island's seismic hazard. The project should also help to increase understanding of the tectonics and geologic evolution of the Caribbean region. The Puerto Rico Seismic Program is being conducted by the Geological Survey with support provided by the Puerto Rico Water Resources Authority, an agency responsible for generation and distribution of electric power throughout the Commonwealth. The Program will include the installation of a network of high quality seismograph stations to monitor seismic activity on and around Puerto Rico. These stations will be distributed across the island to record the seismicity as uniformly as possible. The detection and accurate location of small earthquakes, as well as moderate magnitude shocks, will aid in mapping active seismic zones and in compiling frequency of occurrence statistics which ultimately wil be useful in seismic risk-zoning of hte island. 

  6. Improving the Monitoring, Verification, and Accounting of CO{sub 2} Sequestered in Geologic Systems with Multicomponent Seismic Technology and Rock Physics Modeling

    SciTech Connect

    Alkan, Engin; DeAngelo, Michael; Hardage, Bob; Sava, Diana; Sullivan, Charlotte; Wagner, Donald

    2012-12-31

    Research done in this study showed that P-SV seismic data provide better spatial resolution of geologic targets at our Appalachian Basin study area than do P-P data. This finding is important because the latter data (P-P) are the principal seismic data used to evaluate rock systems considered for CO{sub 2} sequestration. The increase in P-SV{sub 1} resolution over P-P resolution was particularly significant, with P-SV{sub 1} wavelengths being approximately 40-percent shorter than P-P wavelengths. CO{sub 2} sequestration projects across the Appalachian Basin should take advantage of the increased resolution provided by converted-shear seismic modes relative to P-wave seismic data. In addition to S-wave data providing better resolution of geologic targets, we found S-wave images described reservoir heterogeneities that P-P data could not see. Specifically, a channel-like anomaly was imaged in a key porous sandstone interval by P-SV{sub 1} data, and no indication of the feature existed in P-P data. If any stratigraphic unit is considered for CO{sub 2} storage purposes, it is important to know all heterogeneities internal to the unit to understand reservoir compartmentalization. We conclude it is essential that multicomponent seismic data be used to evaluate all potential reservoir targets whenever a CO{sub 2} storage effort is considered, particularly when sequestration efforts are initiated in the Appalachian Basin. Significant differences were observed between P-wave sequences and S- wave sequences in data windows corresponding to the Oriskany Sandstone, a popular unit considered for CO{sub 2} sequestration. This example demonstrates that S-wave sequences and facies often differ from P-wave sequences and facies and is a principle we have observed in every multicomponent seismic interpretation our research laboratory has done. As a result, we now emphasis elastic wavefield seismic stratigraphy in our reservoir characterization studies, which is a science based on the

  7. Robust Satellite Techniques for monitoring earth emitted radiation in the Japanese seismic area by using MTSAT observations in the TIR spectral range

    NASA Astrophysics Data System (ADS)

    Genzano, Nicola; Filizzola, Carolina; Hattori, Katsumi; Lisi, Mariano; Paciello, Rossana; Pergola, Nicola; Tramutoli, Valerio

    2016-04-01

    Since eighties, the fluctuations of Earth's thermally emitted radiation, measured by satellite sensors operating in the thermal infrared (TIR) spectral range, have been associated with the complex process of preparation for major earthquakes. But, like other claimed earthquake precursors (seismological, physical, chemical, biological, etc.) they have been for long-time considered with some caution by scientific community. The lack of a rigorous definition of anomalous TIR signal fluctuations and the scarce attention paid to the possibility that other causes (e.g. meteorological) different from seismic activity could be responsible for the observed TIR variations were the main causes of such skepticism. Compared with previously proposed approaches the general change detection approach, named Robust Satellite Techniques (RST), showed good ability to discriminate anomalous TIR signals possibly associated to seismic activity, from the normal variability of TIR signal due to other causes. Thanks to its full exportability on different satellite packages, since 2001 RST has been implemented on TIR images acquired by polar (e.g. NOAA-AVHRR, EOS -MODIS) and geostationary (e.g. MSG-SEVIRI, NOAA-GOES/W, GMS-5/VISSR) satellite sensors, in order to verify the presence (or absence) of TIR anomalies in presence (absence) of earthquakes (with M>4) in different seismogenic areas around the world (e.g. Italy, Greece, Turkey, India, Taiwan, etc.). In this paper, the RST data analysis approach has been implemented on TIR satellite records collected over Japan by the geostationary satellite sensor MTSAT (Multifunctional Transport SATellites) and RETIRA (Robust Estimator of TIR Anomalies) index was used to identify Significant Sequences of TIR Anomalies (SSTAs) in a possible space-time relations with seismic events. Achieved results will be discussed in the perspective of a multi-parametric approach for a time-Dependent Assessment of Seismic Hazard (t-DASH).

  8. Visualization of volumetric seismic data

    NASA Astrophysics Data System (ADS)

    Spickermann, Dela; Böttinger, Michael; Ashfaq Ahmed, Khawar; Gajewski, Dirk

    2015-04-01

    Mostly driven by demands of high quality subsurface imaging, highly specialized tools and methods have been developed to support the processing, visualization and interpretation of seismic data. 3D seismic data acquisition and 4D time-lapse seismic monitoring are well-established techniques in academia and industry, producing large amounts of data to be processed, visualized and interpreted. In this context, interactive 3D visualization methods proved to be valuable for the analysis of 3D seismic data cubes - especially for sedimentary environments with continuous horizons. In crystalline and hard rock environments, where hydraulic stimulation techniques may be applied to produce geothermal energy, interpretation of the seismic data is a more challenging problem. Instead of continuous reflection horizons, the imaging targets are often steep dipping faults, causing a lot of diffractions. Without further preprocessing these geological structures are often hidden behind the noise in the data. In this PICO presentation we will present a workflow consisting of data processing steps, which enhance the signal-to-noise ratio, followed by a visualization step based on the use the commercially available general purpose 3D visualization system Avizo. Specifically, we have used Avizo Earth, an extension to Avizo, which supports the import of seismic data in SEG-Y format and offers easy access to state-of-the-art 3D visualization methods at interactive frame rates, even for large seismic data cubes. In seismic interpretation using visualization, interactivity is a key requirement for understanding complex 3D structures. In order to enable an easy communication of the insights gained during the interactive visualization process, animations of the visualized data were created which support the spatial understanding of the data.

  9. Downhole Microseismic Monitoring at a Carbon Capture, Utilization, and Storage Site, Farnsworth Unit, Ochiltree County, Texas

    NASA Astrophysics Data System (ADS)

    Ziegler, A.; Balch, R. S.; van Wijk, J.

    2015-12-01

    Farnsworth Oil Field in North Texas hosts an ongoing carbon capture, utilization, and storage project. This study is focused on passive seismic monitoring at the carbon injection site to measure, locate, and catalog any induced seismic events. A Geometrics Geode system is being utilized for continuous recording of the passive seismic downhole bore array in a monitoring well. The array consists of 3-component dual Geospace OMNI-2400 15Hz geophones with a vertical spacing of 30.5m. Downhole temperature and pressure are also monitored. Seismic data is recorded continuously and is produced at a rate of over 900GB per month, which must be archived and reviewed. A Short Term Average/Long Term Average (STA/LTA) algorithm was evaluated for its ability to search for events, including identification and quantification of any false positive events. It was determined that the algorithm was not appropriate for event detection with the background level of noise at the field site and for the recording equipment as configured. Alternatives are being investigated. The final intended outcome of the passive seismic monitoring is to mine the continuous database and develop a catalog of microseismic events/locations and to determine if there is any relationship to CO2 injection in the field. Identifying the location of any microseismic events will allow for correlation with carbon injection locations and previously characterized geological and structural features such as faults and paleoslopes. Additionally, the borehole array has recorded over 1200 active sources with three sweeps at each source location that were acquired during a nearby 3D VSP. These data were evaluated for their usability and location within an effective radius of the array and were stacked to improve signal-noise ratio and are used to calibrate a full field velocity model to enhance event location accuracy. Funding for this project is provided by the U.S. Department of Energy under Award No. DE-FC26-05NT42591.

  10. Decadal-scale variability of diffuse CO2 emissions and seismicity revealed from long-term monitoring (1995-2013) at Mammoth Mountain, California, USA

    NASA Astrophysics Data System (ADS)

    Werner, Cynthia; Bergfeld, Deborah; Farrar, Christopher D.; Doukas, Michael P.; Kelly, Peter J.; Kern, Christoph

    2014-12-01

    Mammoth Mountain, California, is a dacitic volcano that has experienced several periods of unrest since 1989. The onset of diffuse soil CO2 emissions at numerous locations on the flanks of the volcano began in 1989-1990 following an 11-month period of heightened seismicity. CO2 emission rates were measured yearly from 1995 to 2013 at Horseshoe Lake (HSL), the largest tree kill area on Mammoth Mountain, and measured intermittently at four smaller degassing areas around Mammoth from 2006 to 2013. The long-term record at HSL shows decadal-scale variations in CO2 emissions with two peaks in 2000-2001 and 2011-2012, both of which follow peaks in seismicity by 2-3 years. Between 2000 and 2004 emissions gradually declined during a seismically quiet period, and from 2004 to 2009 were steady at ~ 100 metric tonnes per day (t d- 1). CO2 emissions at the four smaller tree-kill areas also increased by factors of 2-3 between 2006 and 2011-2012, demonstrating a mountain-wide increase in degassing. Delays between the peaks in seismicity and degassing have been observed at other volcanic and hydrothermal areas worldwide, and are thought to result from an injection of deep CO2-rich fluid into shallow subsurface reservoirs causing a pressurization event with a delayed transport to the surface. Such processes are consistent with previous studies at Mammoth, and here we highlight (1) the mountain-wide response, (2) the characteristic delay of 2-3 years, and (3) the roughly decadal reoccurrence interval for such behavior. Our best estimate of total CO2 degassing from Mammoth Mountain was 416 t d- 1 in 2011 during the peak of emissions, over half of which was emitted from HSL. The cumulative release of CO2 between 1995 and 2013 from diffuse emissions is estimated to be ~ 2-3 Mt, and extrapolation back to 1989 gives ~ 4.8 Mt. This amount of CO2 release is similar to that produced by the mid-sized (VEI 3) 2009 eruption of Redoubt Volcano in Alaska (~ 2.3 Mt over 11 months), and

  11. DEPTH CONTINUOUS HYDRAULIC CONDUCTIVITY PROFILING USING AN ACTIVE SOURCE PENETROMETER

    NASA Astrophysics Data System (ADS)

    Fitzgerald, M.; Elsworth, D.

    2009-12-01

    A method is developed to recover depth-continuous hydraulic conductivity profiles of an unconsolidated saturated aquifer using an active source penetrometer, the Hydraulic Profiling Tool (HPT). The tool yields estimates of K through continuous injection of fluid in the subsurface from a small port on the probe shaft while controlled measurements of net applied fluid pressure required to maintain a specified flow rate (typically 350 mL/min) are recorded. The tool gathers these data of flow rate and measured applied pressure during halted and constant-rate penetration (typically 2cm/sec) of the probe. The analysis is developed in two parts, first to explore the interplay between advective effects controlled by penetration rate and secondly flow volume effects controlled by the targeted flow rate. These two effects are analyzed through their respective influence on the measured applied pressure response in ΔP/σv’-Q/ΔP space, which shows a linear relationship for the flow rate to applied pressure response when Q/ΔP > 1 and when Q/ΔP < 1 the response tends towards an asymptotic limit representing soil failure limits as ΔP/σv’ > 1. The analysis shows that penetration rate does not significantly influence the applied pressure response at the tested penetration rates (0 ≤ U(cm/s)≤ 4). The targeted applied flow rate does however influence the applied pressure response as flow rates less than ~300 mL/min show a scattering of the data in ΔP/σv’-Q/ΔP space, where above 300 mL/min the data begins to form a linear response. A targeted flow rate of QT = 400mL/min is suggested as a suitable flow rate based on this analysis. Measurements of hydraulic conductivity are then obtained for the HPT data through the derivation of an equation based on a recast form of Darcy’s law where considerations of the flow geometry as K = (QHPT/ΔP)(δw/πΦ). K profiles obtained for the HPT system are then compared against K profiles obtained from an independent method (PSU

  12. Subsurface Monitoring of CO2 Sequestration - A Review and Look Forward

    NASA Astrophysics Data System (ADS)

    Daley, T. M.

    2012-12-01

    The injection of CO2 into subsurface formations is at least 50 years old with large-scale utilization of CO2 for enhanced oil recovery (CO2-EOR) beginning in the 1970s. Early monitoring efforts had limited measurements in available boreholes. With growing interest in CO2 sequestration beginning in the 1990's, along with growth in geophysical reservoir monitoring, small to mid-size sequestration monitoring projects began to appear. The overall goals of a subsurface monitoring plan are to provide measurement of CO2 induced changes in subsurface properties at a range of spatial and temporal scales. The range of spatial scales allows tracking of the location and saturation of the plume with varying detail, while finer temporal sampling (up to continuous) allows better understanding of dynamic processes (e.g. multi-phase flow) and constraining of reservoir models. Early monitoring of small scale pilots associated with CO2-EOR (e.g., the McElroy field and the Lost Hills field), developed many of the methodologies including tomographic imaging and multi-physics measurements. Large (reservoir) scale sequestration monitoring began with the Sleipner and Weyburn projects. Typically, large scale monitoring, such as 4D surface seismic, has limited temporal sampling due to costs. Smaller scale pilots can allow more frequent measurements as either individual time-lapse 'snapshots' or as continuous monitoring. Pilot monitoring examples include the Frio, Nagaoka and Otway pilots using repeated well logging, crosswell imaging, vertical seismic profiles and CASSM (continuous active-source seismic monitoring). For saline reservoir sequestration projects, there is typically integration of characterization and monitoring, since the sites are not pre-characterized resource developments (oil or gas), which reinforces the need for multi-scale measurements. As we move beyond pilot sites, we need to quantify CO2 plume and reservoir properties (e.g. pressure) over large scales, while still

  13. Fluid injection and induced seismicity

    NASA Astrophysics Data System (ADS)

    Kendall, Michael; Verdon, James

    2016-04-01

    The link between fluid injection, or extraction, and induced seismicity has been observed in reservoirs for many decades. In fact spatial mapping of low magnitude events is routinely used to estimate a stimulated reservoir volume. However, the link between subsurface fluid injection and larger felt seismicity is less clear and has attracted recent interest with a dramatic increase in earthquakes associated with the disposal of oilfield waste fluids. In a few cases, hydraulic fracturing has also been linked to induced seismicity. Much can be learned from past case-studies of induced seismicity so that we can better understand the risks posed. Here we examine 12 case examples and consider in particular controls on maximum event size, lateral event distributions, and event depths. Our results suggest that injection volume is a better control on maximum magnitude than past, natural seismicity in a region. This might, however, simply reflect the lack of baseline monitoring and/or long-term seismic records in certain regions. To address this in the UK, the British Geological Survey is leading the deployment of monitoring arrays in prospective shale gas areas in Lancashire and Yorkshire. In most cases, seismicity is generally located in close vicinity to the injection site. However, in some cases, the nearest events are up to 5km from the injection point. This gives an indication of the minimum radius of influence of such fluid injection projects. The most distant events are never more than 20km from the injection point, perhaps implying a maximum radius of influence. Some events are located in the target reservoir, but most occur below the injection depth. In fact, most events lie in the crystalline basement underlying the sedimentary rocks. This suggests that induced seismicity may not pose a leakage risk for fluid migration back to the surface, as it does not impact caprock integrity. A useful application for microseismic data is to try and forecast induced seismicity

  14. Historical seismicity

    USGS Publications Warehouse

    Dengler, L.

    1992-01-01

    The North Coast region of California in the vicinity of Cape Mendocino is one of the state's most seismically active areas, accounting for 25 percent of seismic energy release in California during the last 50 years. the region is located in a geologically dynamic are surrounding the Mendocino triple junction where three of the Earth's tectonic plates join together ( see preceding article by Sam Clarke). In the historic past the North Coast has been affected by earthquakes occurring on the San Andreas fault system to the south, the Mendocino fault to the southwest, and intraplate earthquakes within both the Gorda and North American plates. More than sixty of these earthquakes have caused damage since the mid-1800's. Recent studies indicate that California's North Coast is also at risk with respect to very large earthquakes (magnitude >8) originating along the Cascadia subduction zone. Although the subduction zone has not generated great earthquakes in historic time, paleoseismic evidence suggests that such earthquakes have been generated by the subduction zone in the recent prehistoric past. 

  15. Seismic safety of high concrete dams

    NASA Astrophysics Data System (ADS)

    Chen, Houqun

    2014-08-01

    China is a country of high seismicity with many hydropower resources. Recently, a series of high arch dams have either been completed or are being constructed in seismic regions, of which most are concrete dams. The evaluation of seismic safety often becomes a critical problem in dam design. In this paper, a brief introduction to major progress in the research on seismic aspects of large concrete dams, conducted mainly at the Institute of Water Resources and Hydropower Research (IWHR) during the past 60 years, is presented. The dam site-specific ground motion input, improved response analysis, dynamic model test verification, field experiment investigations, dynamic behavior of dam concrete, and seismic monitoring and observation are described. Methods to prevent collapse of high concrete dams under maximum credible earthquakes are discussed.

  16. Broadband seismology and small regional seismic networks

    USGS Publications Warehouse

    Herrmann, Robert B.

    1995-01-01

    In the winter of 1811-12, three of the largest historic earthquakes in the United States occurred near New Madrid, Missouri. Seismicity continues to the present day throughout a tightly clustered pattern of epicenters centered on the bootheel of Missouri, including parts of northeastern Arkansas, northwestern Tennessee, western Kentucky, and southern Illinois. In 1990, the New Madrid seismic zone/Central United States became the first seismically active region east of the Rocky Mountains to be designated a priority research area within the National Earthquake Hazards Reduction Program (NEHRP). This Professional Paper is a collection of papers, some published separately, presenting results of the newly intensified research program in this area. Major components of this research program include tectonic framework studies, seismicity and deformation monitoring and modeling, improved seismic hazard and risk assessments, and cooperative hazard mitigation studies.

  17. Seismic sources

    DOEpatents

    Green, M.A.; Cook, N.G.W.; McEvilly, T.V.; Majer, E.L.; Witherspoon, P.A.

    1987-04-20

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Longitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements for more than about one minute. 9 figs.

  18. Seismicity at Jalisco-Nayarit Border, Mexico

    NASA Astrophysics Data System (ADS)

    Rutz, M.; Nunez-Cornu, F.; Camarena, M.; Trejo, E.; Reyes-Davila, G.; Suarez-Plasencia, C.

    2003-12-01

    Since 2002 a regional seismic network from Jalisco Civil Defense and University of Guadalalajara is monitoring seismicity at the northwest border of Jalisco block. With the installation of a seismic station on Ceboruco Volcano, by Nayarit Civil Defense, coverage of the network extends to east. Ceboruco Volcano is located on the Tepic-Zacoalco graben, the east border of Jalisco block, this allow us to begin to monitoring this area. The zone of Bahia de Banderas, between the north coast of Jalisco and south coast of Nayarit, probably on a tectonic triple point, is a region of high seismic potential. Activ tectonic structures and clusters in the zone of El Tuito and the Dam Cajon de Pe¤as have been identified. The seismicity in the north area of the bay is low, meanwhile in the south, where the bay is deeper, the seismicity level is higher with an East-West tendency. At the east, the Amatlan de Ca¤as-Ameca zone presents continue activity, here have been possible to locate events with local magnitude between 2 and 4. Tectonovolcanic events registred at Ceboruco station presents waveform with scattering. The seismic distribution of the coast of Jalisco shows parallel alignments to the trench throughout al the coast. Other perpendicular alignments to the coastline show active morphologic structures within the Jalisco block related to the subduction of the Rivera plate under the Jalisco block.

  19. Third Quarter Hanford Seismic Report for Fiscal Year 2005

    SciTech Connect

    Reidel, Steve P.; Rohay, Alan C.; Hartshorn, Donald C.; Clayton, Ray E.; Sweeney, Mark D.

    2005-09-01

    Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network for the U.S. Department of Energy and its contractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The Hanford Seismic Network and the Eastern Washington Regional Network consist of 41 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. For the Hanford Seismic Network, there were 337 triggers during the third quarter of fiscal year 2005. Of these triggers, 20 were earthquakes within the Hanford Seismic Network. The largest earthquake within the Hanford Seismic Network was a magnitude 1.3 event May 25 near Vantage, Washington. During the third quarter, stratigraphically 17 (85%) events occurred in the Columbia River basalt (approximately 0-5 km), no events in the pre-basalt sediments (approximately 5-10 km), and three (15%) in the crystalline basement (approximately 10-25 km). During the first quarter, geographically five (20%) earthquakes occurred in swarm areas, 10 (50%) earthquakes were associated with a major geologic structure, and 5 (25%) were classified as random events.

  20. Annual Hanford Seismic Report for Fiscal Year 2003

    SciTech Connect

    Hartshorn, Donald C.; Reidel, Steve P.; Rohay, Alan C.

    2003-12-01

    This report describes the seismic activity in and around the Hanford Site during Fiscal year 2003. Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network for the U.S. Department of Energy and its contractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The Hanford Seismic Network and the Eastern Washington Regional Network consist of 41 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. For the Hanford Seismic Network, there were 1,336 triggers during fiscal year 2003. Of these triggers, 590 were earthquakes. One hundred and one earthquakes of the 590 earthquakes were located in the Hanford Seismic Network area. Stratigraphically 35 (34.6%) occurred in the Columbia River basalt, 29 (28.7%) were earthquakes in the pre-basalt sediments, and 37 (36.7%) were earthquakes in the crystalline basement. Geographically, 48 (47%) earthquakes occurred in swarm areas, 4 (4%) earthquakes were associated with a major geologic structure, and 49 (49%) were classified as random events. During the third and fourth quarters, an earthquake swarm consisting of 27 earthquakes occurred on the south limb of Rattlesnake Mountain. The earthquakes are centered over the northwest extension of the Horse Heaven Hills anticline and probably occur near the interface of the Columbia River Basalt Group and pre-basalt sediments.

  1. Remaining gaps for "safe" CO2 storage: the INGV CO2GAPS vision of "learning by doing" monitoring geogas leakage, reservoirs contamination/mixing and induced/triggered seismicity

    NASA Astrophysics Data System (ADS)

    Quattrocchi, F.; Vinciguerra, S.; Chiarabba, C.; Boschi, E.; Anselmi, M.; Burrato, P.; Buttinelli, M.; Cantucci, B.; Cinti, D.; Galli, G.; Improta, L.; Nazzari, M.; Pischiutta, M.; Pizzino, L.; Procesi, M.; Rovelli, A.; Sciarra, A.; Voltattorni, N.

    2012-12-01

    The CO2GAPS project proposed by INGV is intended to build up an European Proposal for a new kind of research strategy in the field of the geogas storage. Aim of the project would be to fill such key GAPS concerning the main risks associated to CO2 storage and their implications on the entire Carbon Capture and Storage (CCS) process, which are: i) the geogas leakage both in soils and shallow aquifers, up to indoor seepage; ii) the reservoirs contamination/mixing by hydrocarbons and heavy metals; iii) induced or triggered seismicity and microseismicity, especially for seismogenic blind faults. In order to consider such risks and make the CCS public acceptance easier, a new kind of research approach should be performed by: i) a better multi-disciplinary and "site specific" risk assessment; ii) the development of more reliable multi-disciplinary monitoring protocols. In this view robust pre-injection base-lines (seismicity and degassing) as well as identification and discrimination criteria for potential anomalies are mandatory. CO2 injection dynamic modelling presently not consider reservoirs geomechanical properties during reactive mass-transport large scale simulations. Complex simulations of the contemporaneous physic-chemical processes involving CO2-rich plumes which move, react and help to crack the reservoir rocks are not totally performed. These activities should not be accomplished only by the oil-gas/electric companies, since the experienced know-how should be shared among the CCS industrial operators and research institutions, with the governments support and overview, also flanked by a transparent and "peer reviewed" scientific popularization process. In this context, a preliminary and reliable 3D modelling of the entire "storage complex" as defined by the European Directive 31/2009 is strictly necessary, taking into account the above mentioned geological, geochemical and geophysical risks. New scientific results could also highlighting such opportunities

  2. Towards 4-D Noise-based Seismic Probing of Volcanoes: Perspectives from a Large-N Nodal Experiment on Piton de la Fournaise Volcano

    NASA Astrophysics Data System (ADS)

    Brenguier, F.; Ackerley, N. J.; Nakata, N.; Boué, P.; Campillo, M.; Roux, P.; Shapiro, N.

    2015-12-01

    Noise-based seismology is proving to be a complementary approach to active source or earthquake-based methods for imaging and monitoring the Earth's interior and in particular volcanoes and active faults. Until recently, noise-based imaging and monitoring relied only on the inversion of surface waves reconstructed from correlations of mostly microseismic seismic noise. Compared to body-wave tomography, surface wave tomography succeeds in retrieving lateral sub-surface velocity contrasts but is less efficient in resolving velocity perturbations at depth. Moreover reflected body-waves can carry direct information about sharp interfaces at depth. Extracting body-waves from noise correlations is challenging and the use of Large-N seismic arrays proves to be of great benefit for extracting noisy body-waves from noise-correlations by stacking over a large number of receiver pairs and by applying array processing. The purpose of VolcArray Large-N seismic experiment on Piton de la Fournaise Volcano is to extract body-waves travelling directly through the active magma reservoir located at ~2.5 km depth below the summit crater using noise correlations between arrays of seismic nodes. By beamforming noise on individual arrays, we found an unusual strong directional source of body-wave noise. This is thus a favorable context for retrieving the body-wave component of the Green's function between arrays. However, standard correlation techniques between nodes do not allow deciphering between the reconstructed Green's function and artifacts from the correlation of the strong directional source of body-waves. By applying double beamforming to the noise correlations between arrays, we are able to isolate ballistic body-waves travelling across the magma storage zone at depth. The stability of these reconstructed waves over time is encouraging in the perspectives of high resolution monitoring of the volcano feeding system.

  3. Historical Seismicity of Central Panama

    NASA Astrophysics Data System (ADS)

    Camacho, E.

    2013-05-01

    Central Panama lies in the Panama microplate, neighboring seismically active regions of Costa Rica and Colombia. This region, crossed by the Panama Canal, concentrates most of the population and economic activity of the Republic of Panama. Instrumental observation of earthquakes in Panama began on 1882 by the Compagnie Universelle du Canal Interocéanique de Panama and continued from 1904 to 1977 by the Panama Canal Company. From October 1997 to March 1998 the USGS deployed a temporary digital seismic network. Since 2003 this region is monitored by a digital seismic network operated by the Panama Canal Authority and I complemented by the broad band stations of the University of Panama seismic network. The seismicity in this region is very diffuse and the few events which are recorded have magnitudes less than 3.0. Historical archives and antique newspapers from Spain, Colombia, Panama and the United Sates have been searched looking for historical earthquake information which could provide a better estimate of the seismicity in this region. We find that Panama City has been shaken by two destructive earthquakes in historical times. One by a local fault (i.e. Pedro Miguel fault) on May 2, 1621 (I=Vlll MM), and a subduction event from the North Panama Deformed Belt (NPDB) on September 7, 1882 (I=Vll MM). To test these findings two earthquakes scenarios were generated, using SELENA, for Panama City Old Quarter. Panama City was rebuilt on January 21, 1673, on a rocky point facing the Pacific Ocean after the sack by pirate Morgan on January 28, 1671. The pattern of damage to calicanto (unreinforced colonial masonry) and wood structures for a crustal local event are higher than those for an event from the NPDB and seem to confirm that the city has not been shaken by a major local event since May 2, 1621 and a subduction event since September 7, 1882

  4. Detection capability of the IMS seismic network based on ambient seismic noise measurements

    NASA Astrophysics Data System (ADS)

    Gaebler, Peter J.; Ceranna, Lars

    2016-04-01

    All nuclear explosions - on the Earth's surface, underground, underwater or in the atmosphere - are banned by the Comprehensive Nuclear-Test-Ban Treaty (CTBT). As part of this treaty, a verification regime was put into place to detect, locate and characterize nuclear explosion testings at any time, by anyone and everywhere on the Earth. The International Monitoring System (IMS) plays a key role in the verification regime of the CTBT. Out of the different monitoring techniques used in the IMS, the seismic waveform approach is the most effective technology for monitoring nuclear underground testing and to identify and characterize potential nuclear events. This study introduces a method of seismic threshold monitoring to assess an upper magnitude limit of a potential seismic event in a certain given geographical region. The method is based on ambient seismic background noise measurements at the individual IMS seismic stations as well as on global distance correction terms for body wave magnitudes, which are calculated using the seismic reflectivity method. From our investigations we conclude that a global detection threshold of around mb 4.0 can be achieved using only stations from the primary seismic network, a clear latitudinal dependence for the detection threshold can be observed between northern and southern hemisphere. Including the seismic stations being part of the auxiliary seismic IMS network results in a slight improvement of global detection capability. However, including wave arrivals from distances greater than 120 degrees, mainly PKP-wave arrivals, leads to a significant improvement in average global detection capability. In special this leads to an improvement of the detection threshold on the southern hemisphere. We further investigate the dependence of the detection capability on spatial (latitude and longitude) and temporal (time) parameters, as well as on parameters such as source type and percentage of operational IMS stations.

  5. Seismic sources

    DOEpatents

    Green, Michael A.; Cook, Neville G. W.; McEvilly, Thomas V.; Majer, Ernest L.; Witherspoon, Paul A.

    1992-01-01

    Apparatus is described for placement in a borehole in the earth, which enables the generation of closely controlled seismic waves from the borehole. Pure torsional shear waves are generated by an apparatus which includes a stator element fixed to the borehole walls and a rotor element which is electrically driven to rapidly oscillate on the stator element to cause reaction forces transmitted through the borehole walls to the surrounding earth. Logitudinal shear waves are generated by an armature that is driven to rapidly oscillate along the axis of the borehole relative to a stator that is clamped to the borehole, to cause reaction forces transmitted to the surrounding earth. Pressure waves are generated by electrically driving pistons that press against opposite ends of a hydraulic reservoir that fills the borehole. High power is generated by energizing the elements at a power level that causes heating to over 150.degree. C. within one minute of operation, but energizing the elements for no more than about one minute.

  6. Evaluation of induced seismicity forecast models in the Induced Seismicity Test Bench

    NASA Astrophysics Data System (ADS)

    Király, Eszter; Gischig, Valentin; Zechar, Jeremy; Doetsch, Joseph; Karvounis, Dimitrios; Wiemer, Stefan

    2016-04-01

    Induced earthquakes often accompany fluid injection, and the seismic hazard they pose threatens various underground engineering projects. Models to monitor and control induced seismic hazard with traffic light systems should be probabilistic, forward-looking, and updated as new data arrive. Here, we propose an Induced Seismicity Test Bench to test and rank such models. We apply the test bench to data from the Basel 2006 and Soultz-sous-Forêts 2004 geothermal stimulation projects, and we assess forecasts from two models that incorporate a different mix of physical understanding and stochastic representation of the induced sequences: Shapiro in Space (SiS) and Hydraulics and Seismics (HySei). SiS is based on three pillars: the seismicity rate is computed with help of the seismogenic index and a simple exponential decay of the seismicity; the magnitude distribution follows the Gutenberg-Richter relation; and seismicity is distributed in space based on smoothing seismicity during the learning period with 3D Gaussian kernels. The HySei model describes seismicity triggered by pressure diffusion with irreversible permeability enhancement. Our results show that neither model is fully superior to the other. HySei forecasts the seismicity rate well, but is only mediocre at forecasting the spatial distribution. On the other hand, SiS forecasts the spatial distribution well but not the seismicity rate. The shut-in phase is a difficult moment for both models in both reservoirs: the models tend to underpredict the seismicity rate around, and shortly after, shut-in. Ensemble models that combine HySei's rate forecast with SiS's spatial forecast outperform each individual model.

  7. Multi-channel Linear Array Seismic Interferometry: Insights on Passive Seismic Imaging of the Upper 1 km in an Urban Area

    NASA Astrophysics Data System (ADS)

    Pettinger, E. M.; Stephenson, W. J.; Odum, J. K.

    2015-12-01

    High-resolution active-source seismic imaging in heavily urbanized regions is problematic because equipment deployment is often constrained to linear roadways, where access for active seismic sources may be limited and seismic energy from ambient urban noise can overpower active sources. To investigate the application of linear-array seismic interferometry for obtaining subsurface images in the upper 1 km beneath an urban area, we acquired passive seismic data along two roadways that cross a northern segment of the Seattle fault zone, Washington State. Both of the profiles were collocated with previously acquired active-source reflection lines, which we used as control for interpretations. The interferometry profiles were roughly 1 km in length and were acquired using 8-Hz resonant frequency, vertical-component geophones that were deployed at 5 m spacing (nominally 216 sensors). Approximately 24 hours of data were acquired on each profile over four days (because of permitting and security issues, the equipment could not be deployed overnight). The basic processing sequence used to create virtual source gathers (VSG's) included pre-correlation gain correction, resampling, bandpass filtering, correlation by cross coherence, and VSG editing. After editing, around 18% of the individual virtual sources were retained for further analysis. VSG's were then dip filtered prior to stacking to further mitigate coherent noise. Our VSG's resolve 4-30 Hz Rayleigh waves, propagating at 300-600 m/s, and at least one diving P-wave propagating at roughly 1800 m/s. These apparent velocities are similar to those of comparable wave phases observed in the active-source data. Overall, these newly acquired high-resolution seismic imaging data provide insights into seismic velocity of the upper 1 km across the Seattle fault zone.

  8. Inducing in situ, nonlinear soil response applying an active source

    USGS Publications Warehouse

    Johnson, P.A.; Bodin, P.; Gomberg, J.; Pearce, F.; Lawrence, Z.; Menq, F.-Y.

    2009-01-01

    [1] It is well known that soil sites have a profound effect on ground motion during large earthquakes. The complex structure of soil deposits and the highly nonlinear constitutive behavior of soils largely control nonlinear site response at soil sites. Measurements of nonlinear soil response under natural conditions are critical to advancing our understanding of soil behavior during earthquakes. Many factors limit the use of earthquake observations to estimate nonlinear site response such that quantitative characterization of nonlinear behavior relies almost exclusively on laboratory experiments and modeling of wave propagation. Here we introduce a new method for in situ characterization of the nonlinear behavior of a natural soil formation using measurements obtained immediately adjacent to a large vibrator source. To our knowledge, we are the first group to propose and test such an approach. Employing a large, surface vibrator as a source, we measure the nonlinear behavior of the soil by incrementally increasing the source amplitude over a range of frequencies and monitoring changes in the output spectra. We apply a homodyne algorithm for measuring spectral amplitudes, which provides robust signal-to-noise ratios at the frequencies of interest. Spectral ratios are computed between the receivers and the source as well as receiver pairs located in an array adjacent to the source, providing the means to separate source and near-source nonlinearity from pervasive nonlinearity in the soil column. We find clear evidence of nonlinearity in significant decreases in the frequency of peak spectral ratios, corresponding to material softening with amplitude, observed across the array as the source amplitude is increased. The observed peak shifts are consistent with laboratory measurements of soil nonlinearity. Our results provide constraints for future numerical modeling studies of strong ground motion during earthquakes.

  9. Basic research in nuclear test monitoring: Seismic wave scattering from irregular interfaces. Final technical report, 1 August 1992-31 July 1994

    SciTech Connect

    Schultz, C.A.; Dainty, A.M.; Toksoez, M.N.

    1994-12-16

    We report on two investigations of seismic wave scattering from irregular interfaces. The first is a laboratory study of the scattering of ultrasonic waves incident on a glass surface etched to produce a highly irregular 3-D interface. We find that 2-D numerical simulations predict the 3-D experimental results well at small incident angles. Both numerical and experimental results strongly support the presence of enhanced backscattering. The second study is an analysis of regional P wave coda observed from events recorded at the Scandinavian NORESS, FINESA, and ARCESS arrays and the New England NYNEX array. The F-K spectra of the P coda are dominated by on-azimuth energy with apparent velocities between Pn (or faster) and Lg. Following this analysis, reflection coefficients calculated with a boundary integral scheme are used to study the role irregular interfaces play in the creation of regional P coda. We find that observed crustal scattering in these regions is strikingly consistent with P-P and P-SV scattering from the 2-D irregular Moho and even more consistent with scattering from a 2-D irregular near surface interface.

  10. Real-time monitoring and massive inversion of source parameters of very long period seismic signals: An application to Stromboli Volcano, Italy

    USGS Publications Warehouse

    Auger, E.; D'Auria, L.; Martini, M.; Chouet, B.; Dawson, P.

    2006-01-01

    We present a comprehensive processing tool for the real-time analysis of the source mechanism of very long period (VLP) seismic data based on waveform inversions performed in the frequency domain for a point source. A search for the source providing the best-fitting solution is conducted over a three-dimensional grid of assumed source locations, in which the Green's functions associated with each point source are calculated by finite differences using the reciprocal relation between source and receiver. Tests performed on 62 nodes of a Linux cluster indicate that the waveform inversion and search for the best-fitting signal over 100,000 point sources require roughly 30 s of processing time for a 2-min-long record. The procedure is applied to post-processing of a data archive and to continuous automatic inversion of real-time data at Stromboli, providing insights into different modes of degassing at this volcano. Copyright 2006 by the American Geophysical Union.

  11. Real time monitoring of induced seismicity in the Insheim and Landau deep geothermal reservoirs, Upper Rhine Graben, using the new SeisComP3 cross-correlation detector

    NASA Astrophysics Data System (ADS)

    Vasterling, Margarete; Wegler, Ulrich; Bruestle, Andrea; Becker, Jan

    2016-04-01

    Real time information on the locations and magnitudes of induced earthquakes is essential for response plans based on the magnitude frequency distribution. We developed and tested a real time cross-correlation detector focusing on induced microseismicity in deep geothermal reservoirs. The incoming seismological data are cross-correlated in real time with a set of known master events. We use the envelopes of the seismograms rather than the seismograms themselves to account for small changes in the source locations or in the focal mechanisms. Two different detection conditions are implemented: After first passing a single trace correlation condition, secondly a network correlation is calculated taking the amplitude information of the seismic network into account. The magnitude is estimated by using the respective ratio of the maximum amplitudes of the master event and the detected event. The detector is implemented as a real time tool and put into practice as a SeisComp3 module, an established open source software for seismological real time data handling and analysis. We validated the reliability and robustness of the detector by an offline playback test using four month of data from monitoring the power plant in Insheim (Upper Rhine Graben, SW Germany). Subsequently, in October 2013 the detector was installed as real time monitoring system within the project "MAGS2 - Microseismic Activity of Geothermal Systems". Master events from the two neighboring geothermal power plants in Insheim and Landau and two nearby quarries are defined. After detection, manual phase determination and event location are performed at the local seismological survey of the Geological Survey and Mining Authority of Rhineland-Palatinate. Until November 2015 the detector identified 454 events out of which 95% were assigned correctly to the respective source. 5% were misdetections caused by local tectonic events. To evaluate the completeness of the automatically obtained catalogue, it is

  12. Quantifying Similarity in Seismic Polarizations

    NASA Astrophysics Data System (ADS)

    Eaton, D. W. S.; Jones, J. P.; Caffagni, E.

    2015-12-01

    Measuring similarity in seismic attributes can help identify tremor, low S/N signals, and converted or reflected phases, in addition to diagnosing site noise and sensor misalignment in arrays. Polarization analysis is a widely accepted method for studying the orientation and directional characteristics of seismic phases via. computed attributes, but similarity is ordinarily discussed using qualitative comparisons with reference values. Here we introduce a technique for quantitative polarization similarity that uses weighted histograms computed in short, overlapping time windows, drawing on methods adapted from the image processing and computer vision literature. Our method accounts for ambiguity in azimuth and incidence angle and variations in signal-to-noise (S/N) ratio. Using records of the Mw=8.3 Sea of Okhotsk earthquake from CNSN broadband sensors in British Columbia and Yukon Territory, Canada, and vertical borehole array data from a monitoring experiment at Hoadley gas field, central Alberta, Canada, we demonstrate that our method is robust to station spacing. Discrete wavelet analysis extends polarization similarity to the time-frequency domain in a straightforward way. Because histogram distance metrics are bounded by [0 1], clustering allows empirical time-frequency separation of seismic phase arrivals on single-station three-component records. Array processing for automatic seismic phase classification may be possible using subspace clustering of polarization similarity, but efficient algorithms are required to reduce the dimensionality.

  13. Southern Appalachian Regional Seismic Network

    SciTech Connect

    Chiu, S.C.C.; Johnston, A.C.; Chiu, J.M.

    1994-08-01

    The seismic activity in the southern Appalachian area was monitored by the Southern Appalachian Regional Seismic Network (SARSN) since late 1979 by the Center for Earthquake Research and Information (CERI) at Memphis State University. This network provides good spatial coverage for earthquake locations especially in east Tennessee. The level of activity concentrates more heavily in the Valley and Ridge province of eastern Tennessee, as opposed to the Blue Ridge or Inner Piedmont. The large majority of these events lie between New York - Alabama lineament and the Clingman/Ocoee lineament, magnetic anomalies produced by deep-seated basement structures. Therefore SARSN, even with its wide station spacing, has been able to define the essential first-order seismological characteristics of the Southern Appalachian seismic zone. The focal depths of the southeastern U.S. earthquakes concentrate between 8 and 16 km, occurring principally beneath the Appalachian overthrust. In cross-sectional views, the average seismicity is shallower to the east beneath the Blue Ridge and Piedmont provinces and deeper to the west beneath the Valley and Ridge and the North American craton. Results of recent focal mechanism studies by using the CERI digital earthquake catalog between October, 1986 and December, 1991, indicate that the basement of the Valley and Ridge province is under a horizontal, NE-SW compressive stress. Right-lateral strike-slip faulting on nearly north-south fault planes is preferred because it agrees with the trend of the regional magnetic anomaly pattern.

  14. Code for Calculating Regional Seismic Travel Time

    2009-07-10

    The RSTT software computes predictions of the travel time of seismic energy traveling from a source to a receiver through 2.5D models of the seismic velocity distribution within the Earth. The two primary applications for the RSTT library are tomographic inversion studies and seismic event location calculations. In tomographic inversions studies, a seismologist begins with number of source-receiver travel time observations and an initial starting model of the velocity distribution within the Earth. A forwardmore » travel time calculator, such as the RSTT library, is used to compute predictions of each observed travel time and all of the residuals (observed minus predicted travel time) are calculated. The Earth model is then modified in some systematic way with the goal of minimizing the residuals. The Earth model obtained in this way is assumed to be a better model than the starting model if it has lower residuals. The other major application for the RSTT library is seismic event location. Given an Earth model, an initial estimate of the location of a seismic event, and some number of observations of seismic travel time thought to have originated from that event, location codes systematically modify the estimate of the location of the event with the goal of minimizing the difference between the observed and predicted travel times. The second application, seismic event location, is routinely implemented by the military as part of its effort to monitor the Earth for nuclear tests conducted by foreign countries.« less

  15. Code for Calculating Regional Seismic Travel Time

    SciTech Connect

    BALLARD, SANFORD; HIPP, JAMES; & BARKER, GLENN

    2009-07-10

    The RSTT software computes predictions of the travel time of seismic energy traveling from a source to a receiver through 2.5D models of the seismic velocity distribution within the Earth. The two primary applications for the RSTT library are tomographic inversion studies and seismic event location calculations. In tomographic inversions studies, a seismologist begins with number of source-receiver travel time observations and an initial starting model of the velocity distribution within the Earth. A forward travel time calculator, such as the RSTT library, is used to compute predictions of each observed travel time and all of the residuals (observed minus predicted travel time) are calculated. The Earth model is then modified in some systematic way with the goal of minimizing the residuals. The Earth model obtained in this way is assumed to be a better model than the starting model if it has lower residuals. The other major application for the RSTT library is seismic event location. Given an Earth model, an initial estimate of the location of a seismic event, and some number of observations of seismic travel time thought to have originated from that event, location codes systematically modify the estimate of the location of the event with the goal of minimizing the difference between the observed and predicted travel times. The second application, seismic event location, is routinely implemented by the military as part of its effort to monitor the Earth for nuclear tests conducted by foreign countries.

  16. Analysis of the ambient seismic noise at Bulgarian seismic stations

    NASA Astrophysics Data System (ADS)

    Dimitrova, Liliya; Nikolova, Svetlana

    2010-05-01

    Modernization of Bulgarian National Seismological Network has been performed during a month in 2005. Broadband seismometers and 24-bits digital acquisition systems with dynamic range more than 132dB type DAS130-01 produced by RefTek Inc. were installed at the seismic stations from the existing analog network. In the present study the ambient seismic noise at Bulgarian National Digital Seismological Network (BNDSN) stations is evaluated. In order to compare the performance of the network against international standards the detail analysis of the seismic noise was performed using software and models that are applied in the international practice. The method of McNamara and Bulland was applied and the software code PDFSA was used to determine power spectral density function (PSD) of the background noise and to evaluate the probability density function (PDF). The levels of the ambient seismic noise were determined and the full range of the factors influencing the quality of the data and the performance of a seismic station was analyzed. The estimated PSD functions were compared against two models for high (NHNM) and low (NLNM) noise that are widely used in seismological practice for seismic station monitoring qualities assessment. The mode PDF are used to prepare annual, seasonal, diurnal and frequency analyses of the noise levels at BNDSN stations. The annual analysis shows that the noise levels at the Northern Bulgarian stations are higher than the ones at Central and Southern stations for the microseisms' periods (1sec -7sec). It is well observable at SS PRV and PSN located near Black sea. This is due to the different geological conditions of the seismic stations as well. For the periods of "cultural" noise the power distribution depends on the type of noise sources and as a rule is related to human activities at or near the Earth surface. Seismic stations MPE, VTS and MMB have least mode noise levels and the noisiest stations are PGB, PVL и JMB. The seasonal

  17. Planning and conducting an international seismic data exchange experiment at the center for seismic studies

    NASA Astrophysics Data System (ADS)

    Romney, C.; Huszar, L.; Frazier, G. A.; Campanella, A.; Tiberio, M. A.

    1986-01-01

    This report covers preparations for and the conduct of an international seismic data exchange experiment sponsored by the Group of Scientific Experts, U.N. Conference on Disarmament. Seismic data reports from 37 countries were transmitted over circuits of the WMO/GTS. The data were analyzed at centers in Washington, Moscow and Stockholm and epicenter lists were broadcast to participants. The experiment tested a number of aspects of a proposed nuclear test monitoring system.

  18. The Southern Kansas Seismic Network

    NASA Astrophysics Data System (ADS)

    Terra, F. M.

    2015-12-01

    Historically aseismic Harper and Sumner counties in Southern Kansas experienced a dramatic increase in seismicity beginning in early 2014, coincident with the development of new oil production in the Mississippi Lime Play. In order to better understand the potential relationships between seismicity and oil development, the USGS installed a real-time telemetered seismic network in cooperation with the Kansas Geological Survey, the Kansas Corporation Commission, the Kansas Department of Health and Environment, Harper County, and the Oklahoma Geological Survey. The network began operation in March 2014 with an initial deployment of 5 NetQuakes accelerometers and by July 2014 had expanded to include 10 broadband sites. The network currently has 14 stations, all with accelerometers and 12 with broadband seismometers. The network has interstation spacing of 15 - 25 km and typical azimuthal gap of 80 for well-located events. Data are continuously streamed to IRIS at 200 samples per second from most sites. Earthquake locations are augmented with additional stations from the USGS National Network, Oklahoma Geological Survey Seismic Network, Kansas Seismic Monitoring Network and the Enid Oklahoma Network. Since the spring of 2014 over 7500 earthquakes have been identified with data from this network, 1400 of which have been manually timed and cataloged. Focal depths for earthquakes typically range between 2 and 7 km. The catalog is available at earthquake.usgs.gov/earthquakes/search/ under network code 'Ismpkansas'. The network recorded the largest known earthquake in Harper County, Mw 4.3, on October 2, 2014 and in Sumner County, Mw 4.9, on November 12, 2014. Recorded ground motions at the epicenter of the October earthquake were 0.70 g (PGA) and 12 cm/s (PGV). These high ground motion values agree with near-source recordings made by other USGS temporary deployments in the U. S. midcontinent, indicating a significant shaking hazard from such shallow, moderate

  19. Third Quarter Hanford Seismic Report for Fiscal Year 2000

    SciTech Connect

    DC Hartshorn; SP Reidel; AC Rohay

    2000-09-01

    Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) for the U.S. Department of Energy and its con-tractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The HSN and the Eastern Washington Regional Network (E WRN) consist of 42 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. The HSN uses 21 sites and the EWRN uses 36 sites; both networks share 16 sites. The networks have 46 combined data channels because Gable Butte and Frenchman Hills East are three-component sites. The reconfiguration of the telemetry and recording systems was completed during the first quarter. All leased telephone lines have been eliminated and radio telemetry is now used exclusively. For the HSN, there were 818 triggers on two parallel detection and recording systems during the third quarter of fiscal year (FY) 2000. Thirteen seismic events were located by the Hanford Seismic Network within the reporting region of 46-47{degree} N latitude and 119-120{degree} W longitude; 7 were earthquakes in the Columbia River Basalt Group, 1 was an earthquake in the pre-basalt sediments, and 5 were earthquakes in the crystalline basement. Three earthquakes occurred in known swarm areas, and 10 earthquakes were random occurrences. No earthquakes triggered the Hanford Strong Motion Accelerometers during the third quarter of FY 2000.

  20. Second Quarter Hanford Seismic Report for Fiscal Year 2000

    SciTech Connect

    DC Hartshorn; SP Reidel; AC Rohay

    2000-07-17

    Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) for the US Department of Energy and its contractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The HSN and the Eastern Washington Regional Network (EWRN) consist of 42 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. The HSN uses 21 sites and the EWRN uses 36 sites; both networks share 16 sites. The networks have 46 combined data channels because Gable Butte and Frenchman Hills East are three-component sites. The reconfiguration of the telemetry and recording systems was completed during the first quarter. All leased telephone lines have been eliminated and radio telemetry is now used exclusively. For the HSN, there were 506 triggers on two parallel detection and recording systems during the second quarter of fiscal year (FY) 2000. Twenty-seven seismic events were located by the Hanford Seismic Network within the reporting region of 46--47{degree} N latitude and 119--120{degree} W longitude; 12 were earthquakes in the Columbia River Basalt Group, 2 were earthquakes in the pre-basalt sediments, 9 were earthquakes in the crystalline basement, and 5 were quarry blasts. Three earthquakes appear to be related to geologic structures, eleven earthquakes occurred in known swarm areas, and seven earthquakes were random occurrences. No earthquakes triggered the Hanford Strong Motion

  1. First quarter Hanford seismic report for fiscal year 2000

    SciTech Connect

    DC Hartshorn; SP Reidel; AC Rohay

    2000-02-23

    Hanford Seismic Monitoring provides an uninterrupted collection of high-quality raw and processed seismic data from the Hanford Seismic Network (HSN) for the US Department of Energy and its contractors. Hanford Seismic Monitoring also locates and identifies sources of seismic activity and monitors changes in the historical pattern of seismic activity at the Hanford Site. The data are compiled, archived, and published for use by the Hanford Site for waste management, Natural Phenomena Hazards assessments, and engineering design and construction. In addition, the seismic monitoring organization works with the Hanford Site Emergency Services Organization to provide assistance in the event of a significant earthquake on the Hanford Site. The HSN and the Eastern Washington Regional Network (EWRN) consist of 42 individual sensor sites and 15 radio relay sites maintained by the Hanford Seismic Monitoring staff. The HSN uses 21 sites and the EW uses 36 sites; both networks share 16 sites. The networks have 46 combined data channels because Gable Butte and Frenchman Hills East are three-component sites. The reconfiguration of the telemetry and recording systems was completed during the first quarter. All leased telephone lines have been eliminated and radio telemetry is now used exclusively. For the HSN, there were 311 triggers on two parallel detection and recording systems during the first quarter of fiscal year (FY) 2000. Twelve seismic events were located by the Hanford Seismic Network within the reporting region of 46--47{degree}N latitude and 119--120{degree}W longitude; 2 were earthquakes in the Columbia River Basalt Group, 3 were earthquakes in the pre-basalt sediments, 9 were earthquakes in the crystalline basement, and 1 was a quarry blast. Two earthquakes appear to be related to a major geologic structure, no earthquakes occurred in known swarm areas, and 9 earthquakes were random occurrences. No earthquakes triggered the Hanford Strong Motion Accelerometers

  2. Seismic Imaging from a TBM

    NASA Astrophysics Data System (ADS)

    Swinnen, G.; Thorbecke, J. W.; Drijkoningen, G. G.

    2007-12-01

    Seismic monitoring from the head of a tunnel-boring machine (TBM) enables improved assessment of the risks associated with the tunnel-boring process. The monitoring system provides a live image of ground conditions along the trajectory followed by the TBM and detects local heterogeneities such as boulders, foundations, and other obstacles that commonly pass undetected using local geotechnical techniques. From a seismic perspective, the underground setting of tunnelling projects places limitations on imaging capability. The principal limiting factor is the size of the area upon which transducers can be installed. This limitation requires adjustments to traditional seismic imaging techniques in which a large area is assumed to be available for attaching the transducers. Recently developed short imaging operators take this limitation into account and are used in the examples described herein. The unique conditions of tunnelling yield two advantages over traditional settings in terms of imaging: rotation of the cutter wheel and the lateral progression of the TBM. Rotation of the cutter wheel, upon which the transducers are installed, provides the opportunity to illuminate obstacles from different angles in different recordings. Spatial progression of the TBM enables improvement in the illumination of obstacles and the signal-to-noise ratio by combining recordings from different lateral positions. In this paper, these specific aspects of seismic imaging during tunnelling are discussed via models that represent different cases encountered in actual tunnelling projects. These case studies demonstrate the way in which image quality along the trajectory of the TBM is improved over that in traditional settings. In this way, the risks associated with the tunnelling process can be more accurately assured.

  3. Land subsidence, seismicity and pore pressure monitoring: the new requirements for the future development of oil and gas fields in Italy

    NASA Astrophysics Data System (ADS)

    Macini, P.; Mesini, E.; Panei, L.; Terlizzese, F.

    2015-11-01

    The Emilia earthquake of 2012 (Italy) stimulated a controversial debate concerning the possibility that the event could have been induced or triggered by underground fluids production. The public discussion led the Italian Government to issue a protocol of guidelines for the monitoring of microseismic activity, ground deformation and reservoir pore pressure. The guidelines will be put into operation as soon as practicable when licensing is being considered, and all data provided by mining operators must be made available to the relevant Authorities. The implementation of an outreach and communication program to local residents and administrative authorities is prescribed, so that the civil and scientific community at large can gain confidence that operations are being managed optimally.

  4. Seismic tomography as a tool for measuring stress in mines

    USGS Publications Warehouse

    Scott, Douglas F.; Williams, T.J.; Denton, D.K.; Friedel, M.J.

    1999-01-01

    Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep, >1,220-m (>4,000-ft), underground pillars. If high-stress areas are detected, they can be destressed prior to development or they can be avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient and noninvasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress, engineers will be able to assure that miners are working in a safer environment.Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep, >1,200-m (>4,000-ft), underground pillars. If high-stress areas are detected, they can be destressed prior to development or they can be avoided. High-stress areas can be