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Sample records for alamos seismic network

  1. The Los Alamos Seismic Network (LASN): Improved Network Instrumentation, Local Earthquake Catalog Updates, and Peculiar Types of Data

    NASA Astrophysics Data System (ADS)

    Roberts, P. M.; Ten Cate, J. A.; House, L. S.; Greene, M. K.; Morton, E.; Kelley, R. E.

    2013-12-01

    The Los Alamos Seismic Network (LASN) has operated for 41 years, and provided the data to locate more than 2,500 earthquakes in north-central New Mexico. The network was installed for seismic verification research, as well as to monitor and locate earthquakes near Los Alamos National Laboratory (LANL). LASN stations are the only monitoring stations in New Mexico north of Albuquerque. The original network once included 22 stations in northern Mew Mexico. With limited funding in the early 1980's, the network was downsized to 7 stations within an area of about 15 km (N-S) by 15 km (E-W), centered on Los Alamos. Over the last four years, eight additional stations have been installed, which have considerably expanded the spatial coverage of the network. Currently, 7 stations have broadband, three-component seismometers with digital telemetry, and the remaining 8 have traditional 1 Hz short-period seismometers with either analog telemetry or on-site digital recording. A vertical array of accelerometers was also installed in a wellbore on LANL property. This borehole array has 3-component digital strong-motion sensors. Recently we began upgrading the local strong-motion accelerometer (SMA) network as well, with the addition of high-resolution digitizers and high-sensitivity force-balance accelerometers (FBA). We will present an updated description of the current LASN station, instrumentation and telemetry configurations, as well as the data acquisition and event-detection software structure used to record events in Earthworm. Although more than 2,000 earthquakes were detected and located in north-central New Mexico during the first 11 years of LASN's operation (1973 to 1984), currently only 1-2 earthquakes per month are detected and located within about 150 km of Los Alamos. Over 850 of these nearby earthquakes have been located from 1973 to present. We recently updated the LASN earthquake catalog for north-central New Mexico up through 2012 and most of 2013. Locations

  2. Addressing concerns related to geologic hazards at the site of the proposed Transuranic Waste Facility , TA-63, Los Alamos National Laboratory: focus on the current Los Alamos Seismic Network earthquake catalog, proximity of identified seismic events to the proposed facility , and evaluation of prev

    SciTech Connect

    Roberts, Peter M.; Schultz-Fellenz, Emily S.; Kelley, Richard E.

    2012-04-02

    This technical paper presents the most recent and updated catalog of earthquakes measured by the Los Alamos Seismic Network at and around Los Alamos National Laboratory (LANL), with specific focus on the site of the proposed transuranic waste facility (TWF) at Technical Area 63 (TA-63). Any questions about the data presented herein, or about the Los Alamos Seismic Network, should be directed to the authors of this technical paper. LANL and the Los Alamos townsite sit atop the Pajarito Plateau, which is bounded on its western edge by the Pajarito fault system, a 35-mile-long system locally comprised of the down-to-the-east Pajarito fault (the master fault) and subsidiary down-to-the-west Rendija Canyon, Guaje Mountain, and Sawyer Canyon faults (Figure 1). This fault system forms the local active western margin of the Rio Grande rift near Los Alamos, and is potentially seismogenic (e.g., Gardner et al., 2001; Reneau et al., 2002; Lewis et al., 2009). The proposed TWF area at TA-63 is situated on an unnamed mesa in the north-central part of LANL between Twomile Canyon to the south, Ten Site Canyon to the north, and the headwaters of Canada del Buey to the east (Figure 2). The local bedrock is the Quaternary Bandelier Tuff, formed in two eruptive pulses from nearby Valles caldera, the eastern edge of which is located approximately 6.5 miles west-northwest of the technical area. The older member (Otowi Member) of the Bandelier Tuff has been dated at 1.61 Ma (Izett and Obradovich 1994). The younger member (Tshirege Member) of the Bandelier Tuff has been dated at 1.256 Ma (age from Phillips et al. 2007) and is widely exposed as the mesa-forming unit around Los Alamos. Several discrete cooling units comprise the Tshirege Member. Commonly accepted stratigraphic nomenclature for the Tshirege Member is described in detail by Broxton and Reneau (1995), Gardner et al. (2001), and Lewis et al. (2009). The Tshirege Member cooling unit exposed at the surface at TA-63 is Qbt3

  3. Integrated verification experiment data collected as part of the Los Alamos National Laboratory`s Source Region program. Appendix F: Regional data from Lawrence Livermore National Laboratory and Sandia National Laboratory Seismic Networks

    SciTech Connect

    Taylor, S.R.

    1993-06-11

    A dataset of regional seismograms assembled for a series of Integrated Verification Experiments conducted by the Los Alamos National Laboratory Source Region program is described. The seismic data has been assembled from networks operated by Lawrence Livermore National Laboratory and Sandia National Laboratory. Examples of the data are shown and basic recording characteristics of the network are described. The seismograms are available on a data tape in SAC format upon request.

  4. 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.

  5. 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.

  6. Seismic vulnerability study Los Alamos Meson Physics Facility (LAMPF)

    SciTech Connect

    Salmon, M.; Goen, L.K.

    1995-12-01

    The Los Alamos Meson Physics Facility (LAMPF), located at TA-53 of Los Alamos National Laboratory (LANL), features an 800 MeV proton accelerator used for nuclear physics and materials science research. As part of the implementation of DOE Order 5480.25 and in preparation for DOE Order 5480.28, a seismic vulnerability study of the structures, systems, and components (SSCs) supporting the beam line from the accelerator building through to the ends of die various beam stops at LAMPF has been performed. The study was accomplished using the SQUG GIP methodology to assess the capability of the various SSCs to resist an evaluation basis earthquake. The evaluation basis earthquake was selected from site specific seismic hazard studies. The goals for the study were as follows: (1) identify SSCs which are vulnerable to seismic loads; and (2) ensure that those SSCs screened during die evaluation met the performance goals required for DOE Order 5480.28. The first goal was obtained by applying the SQUG GIP methodology to those SSCS represented in the experience data base. For those SSCs not represented in the data base, information was gathered and a significant amount of engineering judgment applied to determine whether to screen the SSC or to classify it as an outlier. To assure the performance goals required by DOE Order 5480.28 are met, modifications to the SQUG GIP methodology proposed by Salmon and Kennedy were used. The results of this study ire presented in this paper.

  7. Seismic Catalogue and Seismic Network in Haiti

    NASA Astrophysics Data System (ADS)

    Belizaire, D.; Benito, B.; Carreño, E.; Meneses, C.; Huerfano, V.; Polanco, E.; McCormack, D.

    2013-05-01

    The destructive earthquake occurred on January 10, 2010 in Haiti, highlighted the lack of preparedness of the country to address seismic phenomena. At the moment of the earthquake, there was no seismic network operating in the country, and only a partial control of the past seismicity was possible, due to the absence of a national catalogue. After the 2010 earthquake, some advances began towards the installation of a national network and the elaboration of a seismic catalogue providing the necessary input for seismic Hazard Studies. This paper presents the state of the works carried out covering both aspects. First, a seismic catalogue has been built, compiling data of historical and instrumental events occurred in the Hispaniola Island and surroundings, in the frame of the SISMO-HAITI project, supported by the Technical University of Madrid (UPM) and Developed in cooperation with the Observatoire National de l'Environnement et de la Vulnérabilité of Haiti (ONEV). Data from different agencies all over the world were gathered, being relevant the role of the Dominican Republic and Puerto Rico seismological services which provides local data of their national networks. Almost 30000 events recorded in the area from 1551 till 2011 were compiled in a first catalogue, among them 7700 events with Mw ranges between 4.0 and 8.3. Since different magnitude scale were given by the different agencies (Ms, mb, MD, ML), this first catalogue was affected by important heterogeneity in the size parameter. Then it was homogenized to moment magnitude Mw using the empirical equations developed by Bonzoni et al (2011) for the eastern Caribbean. At present, this is the most exhaustive catalogue of the country, although it is difficult to assess its degree of completeness. Regarding the seismic network, 3 stations were installed just after the 2010 earthquake by the Canadian Government. The data were sent by telemetry thought the Canadian System CARINA. In 2012, the Spanish IGN together

  8. Community Seismic Network (CSN)

    NASA Astrophysics Data System (ADS)

    Clayton, R. W.; Heaton, T. H.; Kohler, M. D.; Cheng, M.; Guy, R.; Chandy, M.; Krause, A.; Bunn, J.; Olson, M.; Faulkner, M.

    2011-12-01

    The CSN is a network of low-cost accelerometers deployed in the Pasadena, CA region. It is a prototype network with the goal of demonstrating the importance of dense measurements in determining the rapid lateral variations in ground motion due to earthquakes. The main product of the CSN is a map of peak ground produced within seconds of significant local earthquakes that can be used as a proxy for damage. Examples of this are shown using data from a temporary network in Long Beach, CA. Dense measurements in buildings are also being used to determine the state of health of structures. In addition to fixed sensors, portable sensors such as smart phones are also used in the network. The CSN has necessitated several changes in the standard design of a seismic network. The first is that the data collection and processing is done in the "cloud" (Google cloud in this case) for robustness and the ability to handle large impulsive loads (earthquakes). Second, the database is highly de-normalized (i.e. station locations are part of waveform and event-detection meta data) because of the mobile nature of the sensors. Third, since the sensors are hosted and/or owned by individuals, the privacy of the data is very important. The location of fixed sensors is displayed on maps as sensor counts in block-wide cells, and mobile sensors are shown in a similar way, with the additional requirement to inhibit tracking that at least two must be present in a particular cell before any are shown. The raw waveform data are only released to users outside of the network after a felt earthquake.

  9. Regional seismic networks upgrade encouraged

    NASA Astrophysics Data System (ADS)

    A partnership between the U.S. National Seismic Network (USNSN)—planned by the U.S. Geological Survey for implementation in the early 1990s—and a group of modernized, independently run regional seismic networks is recommended by the National Research Council in their recent report, “Assessing the Nation's Earthquakes: The Health and Future of Regional Seismograph Networks.” The panel that prepared the report said that together, the facilities would constitute a National Seismic System, a satellite-based network capable of systematically monitoring and analyzing earthquakes throughout the nation within minutes of their occurrence.Regional seismic networks are arrays of tens to hundreds of seismic stations targeted chiefly on seismically active regions. They provide a broad range of data and information, which can be applied to public safety and emergency management, quantification of hazard and risk assessment associated with natural and human-induced earthquakes, surveillance of underground nuclear explosions, basic research on earthquake mechanics and dynamics, seismic wave propagation, seismotectonic processes, earthquake forecasting and prediction, and properties and composition of the crust and the internal structure of the Earth.

  10. Community Seismic Network (CSN)

    NASA Astrophysics Data System (ADS)

    Clayton, R. W.; Heaton, T. H.; Kohler, M. D.; Cheng, M.; Guy, R.; Chandy, M.; Krause, A.; Bunn, J.; Olson, M.; Faulkner, M.; Liu, A.; Strand, L.

    2012-12-01

    We report on developments in sensor connectivity, architecture, and data fusion algorithms executed in Cloud computing systems in the Community Seismic Network (CSN), a network of low-cost sensors housed in homes and offices by volunteers in the Pasadena, CA area. The network has over 200 sensors continuously reporting anomalies in local acceleration through the Internet to a Cloud computing service (the Google App Engine) that continually fuses sensor data to rapidly detect shaking from earthquakes. The Cloud computing system consists of data centers geographically distributed across the continent and is likely to be resilient even during earthquakes and other local disasters. The region of Southern California is partitioned in a multi-grid style into sets of telescoping cells called geocells. Data streams from sensors within a geocell are fused to detect anomalous shaking across the geocell. Temporal spatial patterns across geocells are used to detect anomalies across regions. The challenge is to detect earthquakes rapidly with an extremely low false positive rate. We report on two data fusion algorithms, one that tessellates the surface so as to fuse data from a large region around Pasadena and the other, which uses a standard tessellation of equal-sized cells. Since September 2011, the network has successfully detected earthquakes of magnitude 2.5 or higher within 40 Km of Pasadena. In addition to the standard USB device, which connects to the host's computer, we have developed a stand-alone sensor that directly connects to the internet via Ethernet or wifi. This bypasses security concerns that some companies have with the USB-connected devices, and allows for 24/7 monitoring at sites that would otherwise shut down their computers after working hours. In buildings we use the sensors to model the behavior of the structures during weak events in order to understand how they will perform during strong events. Visualization models of instrumented buildings ranging

  11. 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

  12. The Kyrgyz Seismic Network (KNET)

    NASA Astrophysics Data System (ADS)

    Bragin, V. D.; Willemann, R. J.; Matix, A. I.; Dudinskih, R. R.; Vernon, F.; Offield, G.

    2007-05-01

    The Kyrgyz Digital Seismic Network (KNET) is a regional continuous telemetric network of very broadband seismic data. KNET was installed in 1991. The telemetry system was upgraded in 1998. The seismograms are transmitted in near real time. KNET is located along part of the boundary between the northern Tien Shan Mountains and the Kazakh platform. Several major tectonic features are spanned by the network including a series of thrust faults in the Tien Shan, the Chu Valley, and the NW-SE trending ridges north of Bishkek. This network is designed to monitor regional seismic activity at the magnitude 3.5+ level as well as to provide high quality data for research projects in regional and global broadband seismology. The Kyrgyz seismic network array consists of 10 stations - 3 of them with more than 3600 m altitude, 2 mountain repeaters, 1 intermediate data base and 2 data centers. One of data centers is a remote source for IRIS data base. KNET is operated by International Research Center - Geodynamic Proving Ground in Bishkek (IGRC) with the participation of Research Station of the Russian Academy of Sciences (RS RAS) and Kyrgyz Institute of Seismology (KIS). The network consists of Streckeisen STS-2 sensors with 24-bit PASSCAL data loggers. All continuous real-time data are accessible through the IRIS DMC in Seattle with over 95% data availability, which compares favorably to the best networks currently operating worldwide. National institutes of seismology in Kyrgyzstan and Kazakhstan, National Nuclear Centre of Kazakhstan, RS RAS, divisions of the ministries on extreme situations and the institutes of the Russian Academy of Sciences use KNET data for estimating seismic hazards and to study deep-seated structure of researched territory. KNET data is used by National Nuclear Centre of Republic of Kazakhstan, which together with LAMONT laboratory (USA) carries out verification researches and monitoring of nuclear detonations in China, India and Pakistan. The uniform

  13. Building a Smartphone Seismic Network

    NASA Astrophysics Data System (ADS)

    Kong, Q.; Allen, R. M.

    2013-12-01

    We are exploring to build a new type of seismic network by using the smartphones. The accelerometers in smartphones can be used to record earthquakes, the GPS unit can give an accurate location, and the built-in communication unit makes the communication easier for this network. In the future, these smartphones may work as a supplement network to the current traditional network for scientific research and real-time applications. In order to build this network, we developed an application for android phones and server to record the acceleration in real time. These records can be sent back to a server in real time, and analyzed at the server. We evaluated the performance of the smartphone as a seismic recording instrument by comparing them with high quality accelerometer while located on controlled shake tables for a variety of tests, and also the noise floor test. Based on the daily human activity data recorded by the volunteers and the shake table tests data, we also developed algorithm for the smartphones to detect earthquakes from daily human activities. These all form the basis of setting up a new prototype smartphone seismic network in the near future.

  14. Romanian Educational Seismic Network Project

    NASA Astrophysics Data System (ADS)

    Tataru, Dragos; Ionescu, Constantin; Zaharia, Bogdan; Grecu, Bogdan; Tibu, Speranta; Popa, Mihaela; Borleanu, Felix; Toma, Dragos; Brisan, Nicoleta; Georgescu, Emil-Sever; Dobre, Daniela; Dragomir, Claudiu-Sorin

    2013-04-01

    Romania is one of the most active seismic countries in Europe, with more than 500 earthquakes occurring every year. The seismic hazard of Romania is relatively high and thus understanding the earthquake phenomena and their effects at the earth surface represents an important step toward the education of population in earthquake affected regions of the country and aims to raise the awareness about the earthquake risk and possible mitigation actions. In this direction, the first national educational project in the field of seismology has recently started in Romania: the ROmanian EDUcational SEISmic NETwork (ROEDUSEIS-NET) project. It involves four partners: the National Institute for Earth Physics as coordinator, the National Institute for Research and Development in Construction, Urban Planning and Sustainable Spatial Development " URBAN - INCERC" Bucharest, the Babeş-Bolyai University (Faculty of Environmental Sciences and Engineering) and the software firm "BETA Software". The project has many educational, scientific and social goals. The main educational objectives are: training students and teachers in the analysis and interpretation of seismological data, preparing of several comprehensive educational materials, designing and testing didactic activities using informatics and web-oriented tools. The scientific objective is to introduce into schools the use of advanced instruments and experimental methods that are usually restricted to research laboratories, with the main product being the creation of an earthquake waveform archive. Thus a large amount of such data will be used by students and teachers for educational purposes. For the social objectives, the project represents an effective instrument for informing and creating an awareness of the seismic risk, for experimentation into the efficacy of scientific communication, and for an increase in the direct involvement of schools and the general public. A network of nine seismic stations with SEP seismometers

  15. 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.

  16. The Geoscope Seismic Network

    NASA Astrophysics Data System (ADS)

    Leroy, N.; Stutzmann, E.; Maggi, A.; Vallee, M.; Pardo, C.

    2014-12-01

    The GEOSCOPE observatory provides 32 years of continuous broadband data to the scientific community. The 31 GEOSCOPE stations are installed in 19 countries, across all continents and on islands throughout the oceans. They are equipped with three component very broadband seismometers (STS1 or STS2) and 24 or 26 bit digitizers (Q330HR). Seismometers are installed with warpless base plates, which decrease long period noise on horizontal components by up to 15dB. In most stations, a pressure gauge and a thermometer are also installed. In 2014, we upgraded 4 stations: SSB in France, CAN in Australia, ROCAM in Rodrigues and ECH in France. 27 stations send data in real or near real time to the GEOSCOPE Data Center and to tsunami warning centers. Continuous data of all stations are collected in real time or with a delay by the IPGP Data Center in Paris where they are validated, archived and made available to the international scientific community through different interfaces including web services (see details on http://geoscope.ipgp.fr). In 2015, GEOSCOPE data will also be available through the French national data center RESIF. Seismic noise level of the continuous data are computed every 24 hours and accessible via the geoscope web site. GEOSCOPE data are also validated by comparing real and synthetic body wave waveforms using the SCARDEC method (Vallee et al., 2011). The information on earthquake characteristics, on GEOSCOPE data available for each event and on the waveform fit for each channel are available through the geoscope web portal.

  17. Community Seismic Network

    NASA Astrophysics Data System (ADS)

    Clayton, R. W.; Kohler, M. D.; Massari, A.; Heaton, T. H.; Guy, R.; Chandy, M.; Bunn, J.; Strand, L.

    2014-12-01

    The CSN is now in its 3rdyear of operation and has expanded to 400 stations in the Los Angeles region. The goal of the network is to produce a map of strong shaking immediately following a major earthquake as a proxy for damage and a guide for first responders. We have also instrumented a number of buildings with the goal of determining the state of health of these structures before and after they have been shaken. In one 15-story structure, our sensors distributed two per floor, and show body waves propagating in the structure after a moderate local earthquake (M4.4 in Encino, CA). Sensors in a 52-story structure, which we plan to instrument with two sensors per floor as well, show the modes of the building (see Figure) down to the fundamental mode at 5 sec due to a M5.1 earthquake in La Habra, CA. The CSN utilizes a number of technologies that will likely be important in building robust low-cost networks. These include: Distributed computing - the sensors themselves are smart-sensors that perform the basic detection and size estimation in the onboard computers and send the results immediately (without packetization latency) to the central facility. Cloud computing - the central facility is housed in the cloud, which means it is more robust than a local site, and has expandable computing resources available so that it can operate with minimal resources during quiet times but still be able to exploit an very large computing facility during an earthquake. Low-cost/low-maintenance sensors - the MEM sensors are capable of staying onscale to +/- 2g, and can measure events in the Los Angeles Basin a low as magnitude 3.

  18. Jalisco Regional Seismic Network (RESAJ)

    NASA Astrophysics Data System (ADS)

    Nunez-Cornu, F. J.; Suarez Plascencia, C.; Escudero, C. R.; Gomez, A.

    2011-12-01

    Many societies and their economies endure the disastrous consequences of destructive earthquakes. The Jalisco region is exposing to this natural hazard. Scientific knowledge constitutes the only way to avoid or at least to mitigate the negative effects of such events. Accordingly the study of geological and geophysical causes; structural, kinematics and dynamic characteristics; and destructive effects of such events is indispensable. The main objective of this project is to developed capability to monitor and to analyze the potential destructive earthquakes along the Jalisco region. This network will allows us to study the Rivera plate and the Jalisco block seismicity. Ten earthquakes greater than 7.4 occurred in the last 160 years, including the largest Mexican earthquake (8.2) producing considerable damage in the area. During this project we installed 20 telemetric seismic stations and we plan to deploy up to 30. The stations are component by 24 bit A/D, 6 channels Quanterra Q330-6 DAS, Lennartz Triaxial 1Hz wide band seismometer, a triaxial accelerometer episensor Model FBA ES-T from Kinemetrics and solar power supply. The data is transmitted using freewave Ethernet radios or wireless internet links. All stations will transmit the data in to the central at Puerto Vallarta where all data is processed using Antelope system to localize and make preliminary evaluations of the events in almost real time and stored for future research. This network will produce high quality data enough to evaluate the eight previously identified seismic zones along Jalisco.

  19. Community Seismic Network (CSN)

    NASA Astrophysics Data System (ADS)

    Clayton, R. W.; Kohler, M. D.; Heaton, T. H.; Massari, A.; Guy, R.; Bunn, J.; Chandy, M.

    2015-12-01

    The CSN now has approximately 600 stations in the northern Los Angeles region. The sensors are class-C MEMs accelerometers that are packaged with backup power and data memory and are connected to a cloud-based processing system through the Internet. Most of the sensors are located in an xy-spatial network with an average minimum station spacing of 800 m. This density allows the lateral variations in ground motion to be determined, which will lead to detailed microzonation maps of the region. Approximately 100 of the sensors are located on campuses of the Los Angeles Unified School District (LAUSD), and this is part of a plan to provide schools with critical earthquake information immediately following an earthquake using the ShakeCast system. The software system in the sensors is being upgraded to allow on site measurements of PGA and PVA to be sent directly to the ShakeMap and earthquake early warning systems. More than 160 of the sensor packages are located on multiple floors of buildings with typically one or two 3-component sensors per floor. With these data we can identify traveling waves in the building, as well as determine the eigenfrequencies and mode shapes. By monitoring these quantities with high spatial density before, during, and after a major shaking event, we hope to determine the state of health of the structure.

  20. Seismic margins assessment of the plutonium processing facility Los Alamos National Laboratory

    SciTech Connect

    Goen, L.K.; Salmon, M.W.

    1995-12-01

    Results of the recently completed seismic evaluation at the Los Alamos National Laboratory site indicate a need to consider seismic loads greater than design basis for many structures systems and components (SSCs). DOE Order 5480.28 requires that existing SSCs be evaluated to determine their ability to withstand the effects of earthquakes when changes in the understanding of this hazard results in greater loads. In preparation for the implementation of DOE Order 5480.28 and to support the update of the facility Safety Analysis Report, a seismic margin assessment of SSCs necessary for a monitored passive safe shutdown of the Plutonium Processing Facility (PF-4) was performed. The seismic margin methodology is given in EPRI NP-6041-SL, ``A Methodology for Assessment of Nuclear Power Plant Seismic Margin (Revision 1)``. In this methodology, high confidence of low probability of failure (HCLPF) capacities for SSCs are estimated in a deterministic manner. For comparison to the performance goals given in DOE Order 5480.28, the results of the seismic margins assessment were used to estimate the annual probability of failure for the evaluated SSCs. In general, the results show that the capacity for the SSCs comprising PF-4 is high. This is to be expected for a newer facility as PF-4 was designed in the early 1970`s. The methodology and results of this study are presented in this paper.

  1. 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.

  2. The Italian National Seismic Network

    NASA Astrophysics Data System (ADS)

    Michelini, Alberto

    2016-04-01

    The Italian National Seismic Network is composed by about 400 stations, mainly broadband, installed in the Country and in the surrounding regions. About 110 stations feature also collocated strong motion instruments. The Centro Nazionale Terremoti, (National Earthquake Center), CNT, has installed and operates most of these stations, although a considerable number of stations contributing to the INGV surveillance has been installed and is maintained by other INGV sections (Napoli, Catania, Bologna, Milano) or even other Italian or European Institutions. The important technological upgrades carried out in the last years has allowed for significant improvements of the seismic monitoring of Italy and of the Euro-Mediterranean Countries. The adopted data transmission systems include satellite, wireless connections and wired lines. The Seedlink protocol has been adopted for data transmission. INGV is a primary node of EIDA (European Integrated Data Archive) for archiving and distributing, continuous, quality checked data. The data acquisition system was designed to accomplish, in near-real-time, automatic earthquake detection and hypocenter and magnitude determination (moment tensors, shake maps, etc.). Database archiving of all parametric results are closely linked to the existing procedures of the INGV seismic monitoring environment. Overall, the Italian earthquake surveillance service provides, in quasi real-time, hypocenter parameters which are then revised routinely by the analysts of the Bollettino Sismico Nazionale. The results are published on the web page http://cnt.rm.ingv.it/ and are publicly available to both the scientific community and the the general public. This presentation will describe the various activities and resulting products of the Centro Nazionale Terremoti. spanning from data acquisition to archiving, distribution and specialised products.

  3. Seismic engineering for an expanded tritium facility at Los Alamos National Laboratory.

    SciTech Connect

    Volkman, D.E.; Olive, W.B.; Endebrocid, E.E.; Khan, P.K.; Rebillet, W.R.

    1997-10-01

    An existing complex of three single story concrete and masonry shear wall buildings will be integrated into an expanded tritium facility for neutron tube target loading. Known as the NTTL Project, the expanded plant is a major element of the Department of Energy`s tritium program at the Los Alamos National Laboratory. This paper describes seismic evaluation and upgrade modifications for the 1950`s concrete shear wall building; drift analyses of two 1980`s CMU [concrete masonry unit] shear wall buildings; design of a new CMU shear wall building linking existing structures and providing personnel change room services; and design of a new steel frame building housing HVAC and electrical power and communication equipment for the complex. All buildings are closely adjacent and drift analysis to establish separation to prevent pounding is a major seismic engineering concern for the project.

  4. Weighted network analysis of earthquake seismic data

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhijit; Mukherjee, G.; Manna, S. S.

    2015-09-01

    Three different earthquake seismic data sets are used to construct the earthquake networks following the prescriptions of Abe and Suzuki (2004). It has been observed that different links of this network appear with highly different strengths. This prompted us to extend the study of earthquake networks by considering it as the weighted network. Different properties of such weighted network have been found to be quite different from those of their un-weighted counterparts.

  5. The Berkeley Digital Seismic Network

    NASA Astrophysics Data System (ADS)

    Romanowicz, B.; Dreger, D.; Neuhauser, D.; Karavas, W.; Hellweg, M.; Uhrhammer, R.; Lombard, P.; Friday, J.; Lellinger, R.; Gardner, J.; McKenzie, M. R.; Bresloff, C.

    2007-05-01

    Since it began monitoring earthquakes in northern California 120 years ago, the Berkeley Seismological Laboratory (BSL) has been striving to produce the highest quality and most complete seismic data possible in the most modern way. This goal has influenced choices in instrumentation, installation and telemetry, as well as the investment in expertise and manpower. Since the transition to broadband (BB) instrumentation in the mid- 1980s and to a fully digitally telemetered network in the early 1990s, we have continued these efforts. Each of our 25 BB installations includes three component BB seismometers (STS-1s or STS-2) and digital accelerometers to capture the full range of ground motion from distant teleseisms to large, nearby earthquakes (almost 250 dB). The ground motion is recorded on-site by 24 bit dataloggers. Additional environmental parameters, such as temperature and pressure, are also monitored continuously. Many stations record also C-GPS data that is transmitted continuously to the BSL via shared real-time telemetry. The BDSN's first stations were installed in abandoned mines. In the last 15 years, we developed installations using buried shipping containers to reduce environmental noise and provide security and easy access to the equipment. Data are transmitted in real-time at several sampling rates to one or more processing centers, using frame relay, radio, microwave, and/or satellite. Each site has 7-30 days of onsite data storage to guard against data loss during telemetry outages. Each station is supplied with backup batteries to provide power for 3 days. The BDSN real-time data acquisition, earthquake analysis and archiving computers are housed in a building built to "emergency grade" seismic standards, with air conditioning and power backed up by a UPS and a large generator. Data latency and power are monitored by automated processes that alert staff via pager and email. Data completeness and timing quality are automatically assessed on a daily

  6. Seismic Station Functionality Improvements of Seismic Network of Slovenia

    NASA Astrophysics Data System (ADS)

    Sincic, Peter; Tasic, Izidor; Mali, Marko; Pancur, Luka; Vidrih, Renato

    2010-05-01

    The Environmental Agency of the Republic of Slovenia, the Office of Seismology and Geology is responsible for the fast and reliable information about earthquakes, originating in the area of Slovenia and nearby. The Seismic Network of Slovenia, which covers the entire Slovenian territory, involving an area of 20,256 km2, consists of 26 seismic stations equipped with broadband seismometers (CMG-40T, CMG-3ESPC, CMG-3T and STS2) and Quanterra Q730 data loggers. The seismic data is transmitted in real-time to the Data Center in Ljubljana (DCL). Leased lines, xDSL and satellite communication are used for data transfer from stations to DCL. When an event occurs main earthquake parameters (magnitude and the location of the epicenter) can be evaluated at sufficient accuracy only if data from several seismic stations is available. In case of temporary communication failure loss of important seismic data can occur. The duration of communication failure, which exceeds 2 hours can cause data loss. This is due to low memory storage of Quanterra Q730 acquisition unit. In this paper our solution for extending storage capabilities of particular seismic station to several months is presented (momentarily the storage capabilities of particular seismic station lies between 1 and 2 hours). To extend storage capabilities we used a special Industrial Computer (JetBox 8100), which runs on Linux. To collect seismic data from the Q730 unit the acquisition software SeiComP is used. The combination of Q730 and JetBox 8100 assures that in case of temporary communication failure there will be no data loss. Seismic data is simply retrieved from JetBox 8100 (from ring buffer that is generated by SeiComP acquisition software) after communication is once again established. Moreover, an advanced state of health system was build and installed on JetBox 8100, that makes identifying, predicting and solving of different problems quick and effective. With combining Q730 data logger and JetBox 8100 we did

  7. The Plate Boundary Observatory Borehole Seismic Network

    NASA Astrophysics Data System (ADS)

    Hasting, M.; Eakins, J.; Anderson, G.; Hodgkinson, K.; Johnson, W.; Mencin, D.; Smith, S.; Jackson, M.; Prescott, W.

    2006-12-01

    As part of the NSF-funded EarthScope Plate Boundary Observatory, UNAVCO will install and operate 103 borehole seismic stations throughout the western United States. These stations continuously record three- component seismic data at 100 samples per second, using Geo-Space HS-1-LT 2-HZ geophones in a sonde developed by SONDI and Consultants (Duke University). Each seismic package is connected to an uphole Quanterra Q330 data logger and Marmot external buffer, from which UNAVCO retrieves data in real time. UNAVCO uses the Antelope software suite from Boulder Real-Time Technologies (BRTT) for all data collection and transfer, metadata generation and distribution, and monitoring of the network. The first stations were installed in summer 2005, with 19 stations installed by September 2006, and a total of 28 stations expected by December 2006. In a prime example of cooperation between the PBO and USArray components of EarthScope, the USArray Array Network Facility (ANF), operated by UC San Diego, handled data flow and network monitoring for the PBO seismic stations in the initial stages of network operations. We thank the ANF staff for their gracious assistance over the last several months. Data flow in real time from the remote stations to the UNAVCO Boulder Network Operations Center, from which UNAVCO provides station command and control; verification and distribution of metadata; and basic quality control for all data. From Boulder, data flow in real time to the IRIS DMC for final quality checks, archiving, and distribution. Historic data are available from June 2005 to the present, and are updated in real time with typical latencies of less than ten seconds. As of 1 September 2006, the PBO seismic network had returned 60 GB of raw data. Please visit http://pboweb.unavco.org for additional information on the PBO seismic network.

  8. The Budget Guide to Seismic Network Management

    NASA Astrophysics Data System (ADS)

    Hagerty, M. T.; Ebel, J. E.

    2007-05-01

    Regardless of their size, there are certain tasks that all seismic networks must perform, including data collection and processing, earthquake location, information dissemination, and quality control. Small seismic networks are unlikely to possess the resources -- manpower and money -- required to do much in-house development. Fortunately, there are a lot of free or inexpensive software solutions available that are able to perform many of the required tasks. Often the available solutions are all-in-one turnkey packages designed and developed for much larger seismic networks, and the cost of adapting them to a smaller network must be weighed against the ease with which other, non-seismic software can be adapted to the same task. We describe here the software and hardware choices we have made for the New England Seismic Network (NESN), a sparse regional seismic network responsible for monitoring and reporting all seismicity within the New England region in the northeastern U.S. We have chosen to use a cost-effective approach to monitoring using free, off-the-shelf solutions where available (e.g., Earthworm, HYP2000) and modifying freeware solutions when it is easier than trying to adapt a large, complicated package. We have selected for use software that is: free, likely to receive continued support from the seismic or, preferably, larger internet community, and modular. Modularity is key to our design because it ensures that if one component of our processing system becomes obsolete, we can insert a suitable replacement with few modifications to the other modules. Our automated event detection, identification and location system is based on a wavelet transform analysis of station data that arrive continuously via TCP/IP transmission over the internet. Our system for interactive analyst review of seismic events and remote system monitoring utilizes a combination of Earthworm modules, Perl cgi-bin scripts, Java, and native Unix commands and can now be carried out via

  9. Oklahoma seismic network. Final report

    SciTech Connect

    Luza, K.V.; Lawson, J.E. Jr. |

    1993-07-01

    The US Nuclear Regulatory Commission has established rigorous guidelines that must be adhered to before a permit to construct a nuclear-power plant is granted to an applicant. Local as well as regional seismicity and structural relationships play an integral role in the final design criteria for nuclear power plants. The existing historical record of seismicity is inadequate in a number of areas of the Midcontinent region because of the lack of instrumentation and (or) the sensitivity of the instruments deployed to monitor earthquake events. The Nemaha Uplift/Midcontinent Geophysical Anomaly is one of five principal areas east of the Rocky Mountain front that has a moderately high seismic-risk classification. The Nemaha uplift, which is common to the states of Oklahoma, Kansas, and Nebraska, is approximately 415 miles long and 12-14 miles wide. The Midcontinent Geophysical Anomaly extends southward from Minnesota across Iowa and the southeastern corner of Nebraska and probably terminates in central Kansas. A number of moderate-sized earthquakes--magnitude 5 or greater--have occurred along or west of the Nemaha uplift. The Oklahoma Geological Survey, in cooperation with the geological surveys of Kansas, Nebraska, and Iowa, conducted a 5-year investigation of the seismicity and tectonic relationships of the Nemaha uplift and associated geologic features in the Midcontinent. This investigation was intended to provide data to be used to design nuclear-power plants. However, the information is also being used to design better large-scale structures, such as dams and high-use buildings, and to provide the necessary data to evaluate earthquake-insurance rates in the Midcontinent.

  10. Seismic Velocity Measurements at Expanded Seismic Network Sites

    SciTech Connect

    Woolery, Edward W; Wang, Zhenming

    2005-01-01

    Structures at the Paducah Gaseous Diffusion Plant (PGDP), as well as at other locations in the northern Jackson Purchase of western Kentucky may be subjected to large far-field earthquake ground motions from the New Madrid seismic zone, as well as those from small and moderate-sized local events. The resultant ground motion a particular structure is exposed from such event will be a consequence of the earthquake magnitude, the structures' proximity to the event, and the dynamic and geometrical characteristics of the thick soils upon which they are, of necessity, constructed. This investigation evaluated the latter. Downhole and surface (i.e., refraction and reflection) seismic velocity data were collected at the Kentucky Seismic and Strong-Motion Network expansion sites in the vicinity of the Paducah Gaseous Diffusion Plant (PGDP) to define the dynamic properties of the deep sediment overburden that can produce modifying effects on earthquake waves. These effects are manifested as modifications of the earthquake waves' amplitude, frequency, and duration. Each of these three ground motion manifestations is also fundamental to the assessment of secondary earthquake engineering hazards such as liquefaction.

  11. The Belgian National Seismic Monitoring Network

    NASA Astrophysics Data System (ADS)

    van Camp, M.; Lecocq, T.; Vanneste, K.; Rapagnani, G.; Martin, H.; Devos, F.; Bukasa, B.; Hendrickx, M.; Collin, F.; Camelbeeck, T.

    2009-04-01

    The Royal Observatory of Belgium (ROB) is responsible for the seismic activity monitoring in Belgium. For this purpose the ROB operates a network of 24 seismic stations. In addition 18 accelerographs have been installed since 2001 in the most seismic active zones. Seismometers allow detecting and localizing any earthquake of magnitude larger than 1.0 in Belgium and surrounding regions. The location of the accelerometric stations is chosen in function of the type of sub-soil and in some places in function of the nearness of important infrastructures as well. Seven seismic stations are now sending their data in real time to the Observatory (in Uccle) using ADSL lines. This will be increased in a near future. Among them 3 broad-band stations are also sending data to the ORFEUS and IRIS data centres. IRIS also receives data from the Belgian superconducting gravimeter. In addition, in 2010, a broadband borehole seismometer is to be installed at the Princess Elizabeth Antarctic station (71°57' S - 23°20' E), on the bedrock, 180 km away from the coastline. Recently a low-cost seismic alert system was developed for the Belgian territory, based on the connection flow on the ROB website (http://www.seismology.be), in parallel to an automatic control of the "Did you feel it ?" macroseismic inquiries, implemented in 2002. The alert is then confirmed at the latest by the seismic signals from five seismic stations that appear on the website with a delay of more or less ten minutes. It was successfully tested during the earthquake sequence that has been observed in the region at the southwest of Brussels since July 2008.

  12. Evaluation of potential surface rupture and review of current seismic hazards program at the Los Alamos National Laboratory. Final report

    SciTech Connect

    Not Available

    1991-12-09

    This report summarizes the authors review and evaluation of the existing seismic hazards program at Los Alamos National Laboratory (LANL). The report recommends that the original program be augmented with a probabilistic analysis of seismic hazards involving assignment of weighted probabilities of occurrence to all potential sources. This approach yields a more realistic evaluation of the likelihood of large earthquake occurrence particularly in regions where seismic sources may have recurrent intervals of several thousand years or more. The report reviews the locations and geomorphic expressions of identified fault lines along with the known displacements of these faults and last know occurrence of seismic activity. Faults are mapped and categorized into by their potential for actual movement. Based on geologic site characterization, recommendations are made for increased seismic monitoring; age-dating studies of faults and geomorphic features; increased use of remote sensing and aerial photography for surface mapping of faults; the development of a landslide susceptibility map; and to develop seismic design standards for all existing and proposed facilities at LANL.

  13. Puerto Rico Strong Motion Seismic Network

    NASA Astrophysics Data System (ADS)

    Huerta-Lopez, C. I.; Martínez-Cruzado, J. A.; Martínez-Pagan, J.; Santana-Torres, E. X.; Torres-O, D. M.

    2014-12-01

    The Puerto Rico Strong Motion Seismic Network is currently in charge of the operation of: (i) free-field (ff) strong motion stations, (ii) instrumented structures (STR) (Dams, Bridges, Buildings), and (iii) the data acquisition/monitoring and analysis of earthquakes considered strong from the point of view of their intensity and magnitude. All these instruments are deployed in the Puerto Rico Island (PRI), US-, and British-Virgin Islands (BVI), and Dominican Republic (DR). The Puerto Rico Island and the Caribbean region have high potential to be affected by earthquakes that could be catastrophic for the area. The Puerto Rico Strong Motion Seismic Network (actually Puerto Rico Strong Motion Program, PRSMP) has grown since 1970's from 7 ff strong motion stations and one instrumented building with analog accelerographs to 111 ff strong motion stations and 16 instrumented buildings with digital accelerographs: PRI: 88 ff, 16 STR., DR: 13 ff, BVI: 5 ff, 2 STR collecting data via IP (internet), DU (telephone), and stand alone stations The current stage of the PRSMP seismic network, the analysis of moderate earthquakes that were recorded and/or occurred on the island, results of the intensity distribution of selected earthquakes, as well as results of dynamic parameter identification of some of the instrumented structures are here presented.

  14. Tracking glaciers with the Alaska seismic network

    NASA Astrophysics Data System (ADS)

    West, M. E.

    2015-12-01

    More than 40 years ago it was known that calving glaciers in Alaska created unmistakable seismic signals that could be recorded tens and hundreds of kilometers away. Their long monochromatic signals invited studies that foreshadowed the more recent surge in glacier seismology. Beyond a handful of targeted studies, these signals have remained a seismic novelty. No systematic attempt has been made to catalog and track glacier seismicity across the years. Recent advances in understanding glacier sources, combined with the climate significance of tidewater glaciers, have renewed calls for comprehensive tracking of glacier seismicity in coastal Alaska. The Alaska Earthquake Center has included glacier events in its production earthquake catalog for decades. Until recently, these were best thought of as bycatch—accidental finds in the process of tracking earthquakes. Processing improvements a decade ago, combined with network improvements in the past five years, have turned this into a rich data stream capturing hundreds of events per year across 600 km of the coastal mountain range. Though the source of these signals is generally found to be iceberg calving, there are vast differences in behavior between different glacier termini. Some glaciers have strong peaks in activity during the spring, while others peak in the late summer or fall. These patterns are consistent over years pointing to fundamental differences in calving behavior. In several cases, changes in seismic activity correspond to specific process changes observed through other means at particular glacier. These observations demonstrate that the current network is providing a faithful record of the dynamic behavior of several glaciers in coastal Alaska. With this as a starting point, we examine what is possible (and not possible) going forward with dedicated detection schemes.

  15. Wide-area Gigabit networking: Los Alamos HIPPI-SONET Gateway

    SciTech Connect

    St. John, W.B.; DuBois, D.H.

    1995-05-01

    This paper describes a HIPPI-SONET Gateway which has been designed by members of the Computer Network Engineering Group at Los Alamos National Laboratory. The Gateway has been used in the CASA Gigabit Testbed at Caltech, Los Alamos National Laboratory, and the San Diego Supercomputer Center to provide communications between the sites. This paper will also make some qualitative statements as to lessons learned during the deployment and maintenance of this wide area network. We report record throughput for transmission of data across a wide area network. We have sustained data rates using the TCP/IP protocol of 550 Mbits/second and the rate of 792 Mbits/second for raw HIPPI data transfer over the 2,000 kilometers from the San Diego Supercomputer Center to the Los Alamos National Laboratory.

  16. Alaska Volcano Observatory Seismic Network Data Availability

    NASA Astrophysics Data System (ADS)

    Dixon, J. P.; Haney, M. M.; McNutt, S. R.; Power, J. A.; Prejean, S. G.; Searcy, C. K.; Stihler, S. D.; West, M. E.

    2009-12-01

    The Alaska Volcano Observatory (AVO) established in 1988 as a cooperative program of the U.S. Geological Survey, the Geophysical Institute at the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys, monitors active volcanoes in Alaska. Thirty-three volcanoes are currently monitored by a seismograph network consisting of 193 stations, of which 40 are three-component stations. The current state of AVO’s seismic network, and data processing and availability are summarized in the annual AVO seismological bulletin, Catalog of Earthquake Hypocenters at Alaska Volcanoes, published as a USGS Data Series (most recent at http://pubs.usgs.gov/ds/467). Despite a rich seismic data set for 12 VEI 2 or greater eruptions, and over 80,000 located earthquakes in the last 21 years, the volcanic seismicity in the Aleutian Arc remains understudied. Initially, AVO seismic data were only provided via a data supplement as part of the annual bulletin, or upon request. Over the last few years, AVO has made seismic data more available with the objective of increasing volcano seismic research on the Aleutian Arc. The complete AVO earthquake catalog data are now available through the annual AVO bulletin and have been submitted monthly to the on-line Advanced National Seismic System (ANSS) composite catalog since 2008. Segmented waveform data for all catalog earthquakes are available upon request and efforts are underway to make this archive web accessible as well. Continuous data were first archived using a tape backup, but the availability of low cost digital storage media made a waveform backup of continuous data a reality. Currently the continuous AVO waveform data can be found in several forms. Since late 2002, AVO has burned all continuous waveform data to DVDs, as well as storing these data in Antelope databases at the Geophysical Institute. Beginning in 2005, data have been available through a Winston Wave Server housed at the USGS in

  17. Specification goals for a Mars seismic network

    NASA Technical Reports Server (NTRS)

    Davis, Paul M.

    1990-01-01

    A seismic network on Mars should have enough stations (e.g., 24) to characterize the seismicity of the planet for comparison with a diversity of structural features; be comprised of low noise stations, preferably underground, 3 to 4 orders of magnitude more sensitive than those used on Viking; record over a sufficient band-width (DC-30 Hz) to detect micro-earthquakes to normal modes; and record for a sufficient duration (10 years) and data rate (10(exp 8) Mb/day/station) to obtain a data set comparable to that from the Apollo mission to the Moon so that locations of major internal boundaries can be inferred, such as those in the Earth, i.e., crust - lithosphere - asthenosphere - upper - lower phase transitions - outer - inner core. The proposed Mars Global Network Mission provides an opportunity to sense the dynamics and probe the interior of the planet. The seismic objectives, the availability of the instrumentation and trade-offs to meet them are discussed.

  18. National Seismic Network System of Turkey

    NASA Astrophysics Data System (ADS)

    Zunbul, S.; Kadirioğlu, F. T.; Holoğlu, N.; Kartal, R. F.; Kiliç, T.; Yatman, A.; Iravul, Y.; Tüzel, B.

    2009-04-01

    In order to mitigate disaster losses, it is necessary to establish an effective disaster management and risk system. The first step of the management is constituted by preparedness studies before the earthquake (disaster). In order to determinate disaster and risk information it is necessary to have a seismological observation network. Due to the monitoring of the earhquakes in the country-wide scale, recording, evaluation, archieving and to inform to the public autority, the project named "Development of the National Seismic Network Project-USAG" has been started. 6 Three Component Short Period, 63 Broad-band, 13 One Component Short Period stations, 65 Local Network- Broad-band, and 247 accelerometers have been operated in the frame of this project. All of the stations transmit continuously their signal to the ERD (Earthquake Research Department) seismic data center in Ankara. Capability of the network is to determine an earthquake which is minimum local magnitude ML= 2.8 generally, in some region local magnitude threshold is ML=1.5 (the places where the stations are concentrated). Earthquake activity in Turkey and surrounding region has been observed 7 days / 24 hours, in ERD data center in Ankara. After the manuel location of an earthquake, If the magnitude is over 4.0, system sends to SMS message automaticaly to the authorized people and immediately press, public and national-local crisis center, scientific institutions are informed by fax and e-mail. Data exchange has been carried out to EMSC-CSEM. During the İnstallation of the broad-band stations, the seismotectonics of the region has been taken into consideration. Earthqauke record stations are concentrated at the most important fault zones in Turkey; North Anatolian Fault System, East Anatolian Fault System, Bitlis Overlap Belt and Aegean Graben (or opening) System. After 1999 İzmit and Düzce earthquakes, the number of the seismic stations in Turkey have been increased each passing year. In this study

  19. The organization of seismicity on fault networks.

    PubMed Central

    Knopoff, L

    1996-01-01

    Although models of homogeneous faults develop seismicity that has a Gutenberg-Richter distribution, this is only a transient state that is followed by events that are strongly influenced by the nature of the boundaries. Models with geometrical inhomogeneities of fracture thresholds can limit the sizes of earthquakes but now favor the characteristic earthquake model for large earthquakes. The character of the seismicity is extremely sensitive to distributions of inhomogeneities, suggesting that statistical rules for large earthquakes in one region may not be applicable to large earthquakes in another region. Model simulations on simple networks of faults with inhomogeneities of threshold develop episodes of lacunarity on all members of the network. There is no validity to the popular assumption that the average rate of slip on individual faults is a constant. Intermediate term precursory activity such as local quiescence and increases in intermediate-magnitude activity at long range are simulated well by the assumption that strong weakening of faults by injection of fluids and weakening of asperities on inhomogeneous models of fault networks is the dominant process; the heat flow paradox, the orientation of the stress field, and the low average stress drop in some earthquakes are understood in terms of the asperity model of inhomogeneous faulting. PMID:11607672

  20. Seismic active control by neural networks.

    SciTech Connect

    Tang, Y.

    1998-01-01

    A study on the application of artificial neural networks (ANNs) to activate structural control under seismic loads is carried out. The structure considered is a single-degree-of-freedom (SDF) system with an active bracing device. The control force is computed by a trained neural network. The feed-forward neural network architecture and an adaptive back-propagation training algorithm is used in the study. The neural net is trained to reproduce the function that represents the response-excitation relationship of the SDF system under seismic loads. The input-output training patterns are generated randomly. In the back-propagation training algorithm, the learning rate is determined by ensuring the decrease of the error function at each epoch. The computer program implemented is validated by solving the classification of the XOR problem. Then, the trained ANN is used to compute the control force according to the control strategy. If the control force exceeds the actuator's capacity limit, it is set equal to that limit. The concept of the control strategy employed herein is to apply the control force at every time step to cancel the system velocity induced at the preceding time step so that the gradual rhythmic buildup of the response is destroyed. The ground motions considered in the numerical example are the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake in California. The system responses with and without the control are calculated and compared. The feasibility and potential of applying ANNs to seismic active control is asserted by the promising results obtained from the numerical examples studied.

  1. Seismic active control by neutral networks

    SciTech Connect

    Tang, Yu

    1995-12-31

    A study on the application of artificial neural networks (ANNs) to active structural control under seismic loads is carried out. The structure considered is a single-degree-of-freedom (SDF) system with an active bracing device. The control force is computed by a trained neural network. The feedforward neural network architecture and an adaptive backpropagation training algorithm is used in the study. The neural net is trained to reproduce the function that represents the response-excitation relationship of the SDF system under seismic loads. The input-output training patterns are generated randomly. In the backpropagation training algorithm, the learning rate is determined by ensuring the decrease of the error function at each epoch. The computer program implemented is validated by solving the classification of the XOR problem. Then, the trained ANN is used to compute the control force according to the control strategy. If the control force exceeds the actuator`s capacity limit, it is set equal to that limit. The concept of the control strategy employed herein is to apply the control force at every time step to cancel the system velocity induced at the preceding time step so that the gradual rhythmic buildup of the response is destroyed. The ground motions considered in the numerical example are the 1940 El Centro earthquake and the 1979 Imperial Valley earthquake in California. The system responses with and without the control are calculated and compared. The feasibility and potential of applying ANNs to seismic active control is asserted by the promising results obtained from the numerical examples studied.

  2. The Jalisco Seismic Telemetric Network (RESJAL)

    NASA Astrophysics Data System (ADS)

    Nunez-Cornu, F. J.; Nunez-Cornu, F. J.; Reyes-Davila, G.; Reyes-Davila, G.; Suarez-Plascencia, C.; Suarez-Plascencia, C.; Gonzalez-Ledezma, M.; Garcia-Puga, J.

    2001-12-01

    The region of Jalisco is one of the most active seismic regions in Mexico, the main tectonic units in this region are the Jalisco Block and the Rivera Plate. The greatest earthquake (M=8.2) occurred in Mexico in the Twenty-Century (1932) took place in the coast of Jalisco, this was followed by another one (Ms =7.8) fifteen days later. In 1995 an earthquake magnitude 8.0 took place in the coast of Jalisco, but its rupture area was only the southern half of the rupture area proposed for the 1932 earthquakes, these facts suggest the existence of an important seismic Gap in the north coast of Jalisco which includes the area of Bahía de Banderas. However, not only subduction earthquakes occurred in this region there are also large inland earthquakes, such as the December 27, 1568 and February 11, 1872 events. There are also three active volcanoes Sanganguey, Ceboruco and the most active volcano in Mexico, the Colima volcano. In spite of these facts and the risk associated to these processes, there were only one seismological permanent station in Chamela on the coast of Jalisco and an analog telemetric network (RESCO) located on the Colima Volcano and the south part of the Colima Rift Zone (CRZ). By these reasons, the Unidad Estatal de Protección Civil de Jalisco (Jalisco Civil Defense) began a project to install a Digital Telemetric Network in the region in several phases, this project is carrying out jointly with SisVOc UdeG.; due to the size of the area and the topography of the region it is very difficult to get direct telemetric links, by these reasons the network is designed in cells with nodes, where the nodes are the different Campus of the University of Guadalajara located in the region, all Campus are linked by a computer network. First phase started in August 2001, it includes the installation of six stations, each station with a Kinemetrics Everest 24 bit datalogger, GPS time, and a Lennartz LE3Dlite 1Hz sensor, using KNI NMS to control and data acquisition

  3. Seismic event interpretation using fuzzy logic and neural networks

    SciTech Connect

    Maurer, W.J.; Dowla, F.U.

    1994-01-01

    In the computer interpretation of seismic data, unknown sources of seismic events must be represented and reasoned about using measurements from the recorded signal. In this report, we develop the use of fuzzy logic to improve our ability to interpret weak seismic events. Processing strategies for the use of fuzzy set theory to represent vagueness and uncertainty, a phenomena common in seismic data analysis, are developed. A fuzzy-assumption based truth-maintenance-inferencing engine is also developed. Preliminary results in interpreting seismic events using the fuzzy neural network knowledge-based system are presented.

  4. Seismic hazards investigations at Los Alamos National Laboratory, 1984 to 1985

    SciTech Connect

    Gardner, J.N.; House, L.

    1987-10-01

    The Pajarito fault system, part of which skirts the western boundary of Los Alamos National Laboratory, is a major, active structural element of the Rio Grande rift. We have mapped over 100 km of interrelated fault zones and traces that constitute the fault systmem in the vicinity of Los Alamos. The style of deformation in the fault system gradually transforms from normal slip, to normal oblique slip, to dominantly right lateral strike-slip motions from south to north. Most significant movements (>100 m) on the fault system in the vicinity of Los Alamos have occurred within the last 1.1 million years. Portions of the fault system may have associated microseismic activity. Available evidence indicates tha major movements have occurred on the fault system in the last 500,000 years and as recently as 350,000 years ago, 240,000 years ago, 42,000 years ago, possibly <10,000 years ago, and 2000 years ago. Some limited, inferential field data imply the fault system generates characteristic earthquakes in the magnitude (Richter) range 6.5 to 7.8. Extrapolation of frequency-magnitude relations, derived from the 10 years of data from the Los Alamos seismograph net, to estimate large expectable earthquakes is unrealistic, and based on the findings of other workers the result is most likely a substantial underestimate. 77 refs., 11 figs., 4 tabs.

  5. Alaska Seismic Network Upgrade and Expansion

    NASA Astrophysics Data System (ADS)

    Sandru, J. M.; Hansen, R. A.; Estes, S. A.; Fowler, M.

    2009-12-01

    such as ANSS, Alaska Volcano Observatory, Bradley Lake Dam, Red Dog Mine, The Plate Boundary Observatory (PBO), Alaska Tsunami Warning Center, and City and State Emergency Managers has helped link vast networks together so that the overall data transition can be varied. This lessens the likelihood of having a single point of failure for an entire network. Robust communication is key to retrieving seismic data. AEIC has gone through growing pains learning how to harden our network and encompassing the many types of telemetry that can be utilized in today's world. Redundant telemetry paths are a goal that is key to retrieving data, however at times this is not feasible with the vast size and terrain in Alaska. We will demonstrate what has worked for us and what our network consists of.

  6. Studying Fin Whales with Seafloor Seismic Networks

    NASA Astrophysics Data System (ADS)

    Wilcock, W. S.; Soule, D. C.; Weirathmueller, M.; Thomson, R.

    2011-12-01

    Baleen whales are found throughout the world's oceans and their welfare captivates the general public. Depending on the species, baleen whales vocalize at frequencies ranging from ~10 Hz to several kilohertz. Passive acoustic studies of whale calls are used to investigate behavior and habitat usage, monitor the recovery of populations from whaling and assess the impacts of anthropogenic sounds. Since airguns are a significant source of sound in the oceans, the research goals of academic seismologists can lead to conflicts with those who advocate for whale conservation while being unwilling to consider the societal benefits of marine geophysical studies. In contrast, studies that monitor earthquakes with ocean bottom seismometers (OBSs) provide an opportunity to enhance studies of baleen whales and improve relationships with environmental advocates. The bandwidth of the typical high-frequency or intermediate-band ocean bottom seismometer overlaps the call frequency of the two largest baleen whale species; blue whales generate sequences of 10- to 20-s-long calls centered at ~16 Hz and fin whales produce long sequences of downswept 1-s-long chirps centered at ~20 Hz. Several studies have demonstrated the potential of OBS networks to monitor calling patterns and determine tracks for fin and blue whales. We will summarize the results from a study to track fin whales near the Endeavour hydrothermal vent fields on the Juan de Fuca Ridge and investigate a potential correlation between the density of whales and enhanced zooplankton found throughout the water column overlying the vent fields. From 2003-2006 an 8-station local seismic network that was designed to monitor hydrothermal earthquakes also recorded ~300,000 fin whale vocalizations, mostly in the fall and winter. Automatic picking and localization techniques that are analogous to those used to analyze earthquakes are employed to determine whale tracks. The tracks are then used to interpret calling patterns in the

  7. Improved characterization of local seismicity using the Dubai Seismic Network, United Arab Emirates

    NASA Astrophysics Data System (ADS)

    Al Khatibi, Eman; Abou Elenean, K. M.; Megahed, A. S.; El-Hussain, I.

    2014-08-01

    In April 2006, Dubai Municipality established a broadband seismological network in Dubai Emirate, United Arab Emirates (UAE). This network was the first seismic network in UAE and consists of four remote seismic stations to observe local and regional seismic activity that may have an effect on Dubai Emirate and the surrounding areas. The network exchanges real-time data with the National Center of Meteorology and Seismology in Abu Dhabi, the Earthquake Monitoring Center in Oman and imports in real-time data from few Global Seismic Network stations, which increases the aperture of the network. In April 2012, Dubai Municipality installed an additional five free-field strong motion stations inside the urban area to estimate and publish real-time ShakeMaps for public and decision makers. Although the local seismic activity from April 2006 to June 2013 reflects low seismic activity with the Emirate, it indicates active tectonics in the relatively aseismic northern Oman Mountains region. A few inland clusters of micro-to-small earthquakes have been identified with the new network. A clear cluster of small-to-moderate earthquakes took place in the eastern part of UAE to the east of Masafi, while two clusters of micro-to-small earthquakes took place at Wadi Nazwa and northern Huwaylat. Focal mechanisms of few well recorded earthquakes in this region indicate normal faulting, generally trending NE in parallel to the transition shear zone between the collision at Zagros and the subduction at the Makran zone.

  8. 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

  9. The Algerian Seismic Network: Performance from data quality analysis

    NASA Astrophysics Data System (ADS)

    Yelles, Abdelkarim; Allili, Toufik; Alili, Azouaou

    2013-04-01

    Seismic monitoring in Algeria has seen a great change after the Boumerdes earthquake of May 21st, 2003. Indeed the installation of a New Digital seismic network (ADSN) upgrade drastically the previous analog telemetry network. During the last four years, the number of stations in operation has greatly increased to 66 stations with 15 Broad Band, 02 Very Broad band, 47 Short period and 21 accelerometers connected in real time using various mode of transmission ( VSAT, ADSL, GSM, ...) and managed by Antelope software. The spatial distribution of these stations covers most of northern Algeria from east to west. Since the operation of the network, significant number of local, regional and tele-seismic events was located by the automatic processing, revised and archived in databases. This new set of data is characterized by the accuracy of the automatic location of local seismicity and the ability to determine its focal mechanisms. Periodically, data recorded including earthquakes, calibration pulse and cultural noise are checked using PSD (Power Spectral Density) analysis to determine the noise level. ADSN Broadband stations data quality is controlled in quasi real time using the "PQLX" software by computing PDFs and PSDs of the recordings. Some other tools and programs allow the monitoring and the maintenance of the entire electronic system for example to check the power state of the system, the mass position of the sensors and the environment conditions (Temperature, Humidity, Air Pressure) inside the vaults. The new design of the network allows management of many aspects of real time seismology: seismic monitoring, rapid determination of earthquake, message alert, moment tensor estimation, seismic source determination, shakemaps calculation, etc. The international standards permit to contribute in regional seismic monitoring and the Mediterranean warning system. The next two years with the acquisition of new seismic equipment to reach 50 new BB stations led to

  10. Interpretation of seismic multiattributes using a neural network

    NASA Astrophysics Data System (ADS)

    Kuroda, Michelle Chaves; Vidal, Alexandre Campane; de Carvalho, Ancilla Maria Almeida

    2012-10-01

    Geological bodies in 2D seismic section are characterized by differences from the surrounding response. These differences can be highlighted by attributes that are sensitive to the desired feature. In this paper the attributes were carefully chosen and trained by a neural network. These seismic attributes are transformed into a new attribute that allows a different view of the seismic lines. The database used for this study is a 2D seismic line of the Taubaté Basin, São Paulo State, Brazil. Two seismic sets were analyzed and the results bring out the horizons and the boundary between seismic units, which helps a better understanding of the evolution of the Taubaté sedimentary basin.

  11. The development of the Moldova digital seismic network

    NASA Astrophysics Data System (ADS)

    Ilies, I.; Ionescu, C.; Grigore, A. G.

    2009-04-01

    The Republic of Moldova is located in the seismically active region, about 70% of its area is predisposed to shaking intensity 7 - 8 points MSK. Focal zones of the primary seismic danger to the territory of the Republic of Moldova are: Vrancea zone - for the whole of its territory and Dobrogea zone - for the southern part. Monitoring of seismic instrumentation in the republic is provided by the Center of Experimental Seismology, Institute of Geology and Seismology, Academy of Sciences of Moldova. According to the seismic zoning map of the Republic of Moldova, seismic stations "Cahul, Leova" and "Giurgiulesti" located in 8 - degree zone, the central regional station "Chisinau" - in 7 - degree, a station "Soroca" - in 6 - degree zone MSK scale. The development of seismic network since 2004, going through a transition to a modern digital recording, improving working conditions for staff and the construction of new buildings for seismic stations, equipping the new network equipment and improve the methods of collecting and processing seismic data. The works to modernize the network of seismic stations in Moldova were initiated in 2003 with the acquisition of the first three axial digital accelerometer. The device was installed initially in Chisinau, and from it we received the first digital recordings of earthquakes from September 27 and October 27, 2004. In joint efforts with National Institute of Research and Development for Earth Physics from Bucharest, Romania, four seismic stations from Republic of Moldavia was upgraded by broadband and strong motion sensors connected at Q 330 digital recorders that issue continuous recording and real time data stream. Starting from spring of 2008, real time seismic data exchange between IGG Republic of Moldavia and NIEP Romania is running using internet connection.

  12. MyShake: Building a smartphone seismic network

    NASA Astrophysics Data System (ADS)

    Kong, Q.; Allen, R. M.; Schreier, L.

    2014-12-01

    We are in the process of building up a smartphone seismic network. In order to build this network, we did shake table tests to evaluate the performance of the smartphones as seismic recording instruments. We also conducted noise floor test to find the minimum earthquake signal we can record using smartphones. We added phone noises to the strong motion data from past earthquakes, and used these as an analogy dataset to test algorithms and to understand the difference of using the smartphone network and the traditional seismic network. We also built a prototype system to trigger the smartphones from our server to record signals which can be sent back to the server in near real time. The phones can also be triggered by our developed algorithm running locally on the phone, if there's an earthquake occur to trigger the phones, the signal recorded by the phones will be sent back to the server. We expect to turn the prototype system into a real smartphone seismic network to work as a supplementary network to the existing traditional seismic network.

  13. The Hellenic Seismic Network (HL): Recent Upgrades and Developments

    NASA Astrophysics Data System (ADS)

    Melis, N. S.; Evangelidis, C. P.; Boukouras, K.; Kalogeras, I. S.; Makropoulos, K.

    2012-04-01

    The Institute of Geodynamics, National Observatory of Athens (NOA-IG) monitors seismicity in Greece since its foundation in 1893. Upgrades with results towards a modernized digital seismic network started back in 2000 and they were continued since then in stages, as national funds were made available as well as more personnel was employed. The most recent upgrade started in 2007, with a dedicated project aiming to establish a Unified National Seismic Network and to link the Hellenic National Seismic Network of NOA-IG with the three Universities: Athens, Thessaloniki and Patras, which also operate local seismic networks. Although the four joining networks are operated independently, with each partner taking responsibility for the operation of its own network, the project upgrade achieved the update - improvement of every network and the seismic waveform data to be made available in near real time amongst the four partners. In parallel, a new upgraded National Strong Motion Network at NOA-IG is under way, giving the opportunity to join the continuous monitored accelerometric data in real time with the available broadband data and furthermore to upgrade existing seismic stations by deploying also an accelerometer next to the broadband sensor. Experiences through troubleshooting, methodologies and tools used to improve operation and examples of recordings from the new established infrastructure are presented, explaining the developments - improvements achieved at every stage until today. Specific earthquake recorded examples are shown, in order to explain the new possibilities opened for detail investigation and operational preparedness established on line in the 24/7 operational center at NOA-IG in Athens, as well as to other operating as backup centers. Further developments and operations using the present resulted operational - research infrastructure and the databases that are made available are also explained and presented.

  14. 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.

  15. 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

  16. Introduction of digital object identifiers (DOI) for seismic networks

    NASA Astrophysics Data System (ADS)

    Evans, Peter; Strollo, Angelo; Clark, Adam; Ahern, Tim; Newman, Rob; Clinton, John; Pequegnat, Catherine; Pedersen, Helle

    2015-04-01

    Proper attribution for scientific source data is important in promoting transparency and recognising the role of data providers in science. Data sets such as those produced by seismic networks now need to be citable and permanently locatable for research users. Recently the EIDA and IRIS-DMC communities have worked together on development of methods for generation, maintenance and promotion of persistent identifiers for seismic networks. This resulted in a 2014 Recommendation by the International Federation of Digital Seismograph Networks (FDSN) on the use of Digital Object Identifiers (DOI) for seismic networks. These can be cited equivalently to scientific papers, and tools such as DataCite allow the tracking of citations to these datasets. The GEOFON, IRIS and RESIF data centres have now begun to roll-out of these seismic network DOIs. This has involved working with principal investigators to prepare metadata consistent with the FDSN recommendation, preparation of landing pages, and changes to the web sites to promote DOIs where available. This has involved preparing improved descriptions of the data (metadata) and clarifying how individuals and institutions should best be recognised for their contributions to making the data available. We illustrate this process for a few representative networks. We will be in contact with additional network operators to help them establish DOIs for their networks in future.

  17. Neural network estimate of seismic velocities and resistivity of rocks from electromagnetic and seismic sounding data

    NASA Astrophysics Data System (ADS)

    Spichak, V. V.; Goidina, A. G.

    2016-05-01

    The neural network estimates of seismic P- and S-wave velocities from electrical resistivity of the rocks and, vice versa, resistivity estimates from seismic velocities are presented. It is shown that, depending on the ratio between the volumes of the known data and the data to be reconstructed, the accuracy of the estimates of the P- and S-wave velocities ranges within 1-4 and 4-6%, respectively. The logarithmic resistivity is estimated from seismic P- and S-velocities as accurately as up to 15-17%. In all cases, the biggest errors are obtained when the estimates are based on correlated data.

  18. 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.

  19. Indian Ocean ridge seismicity observed with a permanent hydroacoustic network

    NASA Astrophysics Data System (ADS)

    Hanson, Jeffrey A.; Bowman, J. Roger

    2005-03-01

    The distribution of earthquakes along the Indian Ocean ridge system between January 18 and October 20, 2003 is investigated using data from two hydrophone stations of the International Monitoring System's global network. Coherent array processing of earthquake-induced hydroacoustic T-waves is used to determine precise arrival times and back azimuths that allow automatic location of the earthquakes. We observed 4725 events throughout the Indian Ocean Basin. Here, we examine 1146 earthquakes from the Central and Southeast Indian Ridge. Source level estimates from the hydroacoustic signals indicate that the hydroacoustic network is at least one magnitude unit more sensitive than the seismic network for Indian Ocean ridge earthquakes. The seismicity primarily clusters at ridge transform offsets. Events are observed off the ridge axis near Boomerang and St. Pierre Seamounts, the active expression of the Amsterdam-St. Paul Hotspot. Seismic gaps are observed at several ridge segments with anomalous bathymetric highs.

  20. High-precision geologic mapping to evaluate the potential for seismic surface rupture at TA-55, Los Alamos National Laboratory

    SciTech Connect

    Gardner, J.N.; Lavine, A.; Vaniman, D.; WoldeGabriel, G.

    1998-06-01

    In this report the authors document results of high-precision geologic mapping in the vicinity of TA-55 that has been done to identify parts of the southern portion of the Rendija Canyon Fault, or any other faults, with the potential for seismic surface rupture. To assess the potential for surface rupture at TA-55, an area of approximately 3 square miles that includes the Los Alamos County Landfill and Twomile, Mortandad, and Sandia Canyons has been mapped in detail. Map units are mostly cooling or flow units within the Tshirege Member (1.2 Ma) of the Bandelier Tuff. Stratigraphic markers that are useful for determining offsets in the map area include a distinct welding break at or near the cooling Unit 2-Unit 3 contact, and the Unit 3-Unit 4 contact. At the County Landfill the contact between the Tshirege Member of the Bandelier Tuff and overlying Quaternary alluvium has also been mapped. The mapping indicates that there is no faulting in the near-surface directly below TA-55, and that the closest fault is about 1500 feet west of the Plutonium Facility. Faulting is more abundant on the western edge of the map area, west of TA-48 in uppermost Mortandad Canyon, upper Sandia Canyon, and at the County Landfill. Measured vertical offsets on the faults range from 1 to 8 feet on mapped Bandelier Tuff contacts. Faulting exposed at the Los Alamos County Landfill has deformed a zone over 1000 feet wide, and has a net vertical down-to-the-west displacement of at least 15 feet in the Bandelier Tuff. Individual faults at the landfill have from less than 1 foot to greater than 15 feet of vertical offset on the Bandelier Tuff. Most faults in the landfill trend N-S, N20W, or N45E. Results of the mapping indicate that the Rendija Canyon Fault does not continue directly south to TA-55. At present, the authors have insufficient data to connect faulting they have mapped to areas of known faulting to the north or south of the study area.

  1. Studies of infrasound propagation using the USArray seismic network (Invited)

    NASA Astrophysics Data System (ADS)

    Hedlin, M. A.; Degroot-Hedlin, C. D.; Walker, K. T.

    2010-12-01

    Although there are currently ~ 100 infrasound arrays worldwide, more than ever before, the station density is still insufficient to provide validation for detailed propagation modeling. Much structure in the atmosphere is short-lived and occurs at spatial scales much smaller than the average distance between infrasound stations. Relatively large infrasound signals can be observed on seismic channels due to coupling at the Earth's surface. Recent research, using data from the 70-km spaced 400-station USArray and other seismic network deployments, has shown the value of dense seismic network data for filling in the gaps between infrasound arrays. The dense sampling of the infrasound wavefield has allowed us to observe complete travel-time branches of infrasound signals and shed more light on the nature of infrasound propagation. We present early results from our studies of impulsive atmospheric sources, such as series of UTTR rocket motor detonations in Utah. The Utah blasts have been well recorded by USArray seismic stations and infrasound arrays in Nevada and Washington State. Recordings of seismic signals from a series of six events in 2007 are used to pinpoint the shot times to < 1 second. Variations in the acoustic branches and signal arrival times at the arrays are used to probe variations in atmospheric structure. Although we currently use coupled signals we anticipate studying dense acoustic network recordings as the USArray is currently being upgraded with infrasound microphones. These new sensors will allow us to make semi-continental scale network recordings of infrasound signals free of concerns about how the signals observed on seismic channels were modified when being coupled to seismic.

  2. Observation of seismicity based on DOMERAPI and BMKG seismic networks: A preliminary result from DOMERAPI project

    NASA Astrophysics Data System (ADS)

    Ramdhan, Mohamad; Nugraha, Andri Dian; Widiyantoro, Sri; Kristyawan, Said; Sembiring, Andry Syaly; Mtaxian, Jean-Philippe

    2016-05-01

    DOMERAPI project has involved earth scientists from Indonesia and France to conduct comprehensively a study of the internal structure of Mt. Merapi and its vicinity based on seismic tomographic imaging. The DOMERAPI seismic network was running from October 2013 to April 2015 consisting of 53 broad-band seismometers, covering Mt. Merapi and Mt. Merbabu, and some geological features such as Opak and Dengkeng faults. Earthquake hypocenter determination conducted in this study is an important step before seismic tomographic imaging. The earthquake events were identified and picked manually and carefully. The majority of earthquakes occured outside the DOMERAPI network. The ray paths of seismic waves from these earthquakes passed through the deep part of the study area around Merapi. The joint data of BMKG and DOMERAPI networks can minimize the azimuthal gap, which is often used to obtain an indication of the reliability of the epicentral solution. Our preliminary results show 279 events from October 2013 to mid August 2014. For future work, we will incorporate the BPPTKG (Center for Research and Technology Development of Geological Disaster) data catalogue in order to enrich seismic ray paths. The combined data catalogues will provide information as input for further advanced studies and volcano hazards mitigation.

  3. Gran Canaria temporary broadband seismic network: an study of the seismicity and Earth structure

    NASA Astrophysics Data System (ADS)

    Almendros, Javier; de Lis Mancilla, Flor; Martinez-Arevalo, Carmen; Carmona, Enrique; Sanchez, Nieves; Heit, Benjamin; Garcia, Alicia; Martin-Leon, Rosa; Buontempo, Luisa; Yuan, Xiahoui

    2010-05-01

    The present project is a joint effort between different institutions to deploy a dense seismic network at Gran Canaria island (Canary Islands, Spain). The interstation distance is around 20 km. The broadband seismic network is composed of one permanent (Guralp CMG-3T 120 s) and five temporary stations (Guralp CMG-3ESP 60 s). The permanent station is a 120 s Guralp CMG-3T and belongs to the Canary Island Seismic Network, run by the Instituto Geográfico Nacional (IGN) of Spain. The temporary stations are 60 s Guralp CMG-3ESP, provided by the GFZ seismic pool. The deployment was carried out in December 2009. The stations will be recording during two years. The improvement of the seismic network allow us to tackle the following issues: the detection and analysis of any local seismicity of tectonic and/or volcanic origin at Gran Canaria island; to contribute to the understanding of the regional seismicity with special interest in the oceanic channel between Tenerife and Gran Canaria Island in collaboration with a project running a dense temporary seismic network in Tenerife; to study the crustal and upper mantle structure, under Gran Canaria to constrain the crustal structure, the source of the volcanism, and better sample the mantle discontinuities and anisotropy. To study the Earth structure, we use receiver function analysis, ambient seismic noise and SKS anisotropy techniques, This project is part of a long-term research of the crustal and the mantle structure of the Canary Islands, which has started with Gran Canaria and Tenerife Islands and will eventually continue with the rest of the archipelago. The origin of the Canary Islands is generally attributed to a broad mantle upwelling under a slow moving plate, resulting in spatially and temporally distributed volcanic activity and a large number of seamounts and islands. A controversial discussion has been going on about the factors that control the evolution of the volcanic edifices, the type of the melting

  4. Virginia Regional Seismic Network. Final report (1986--1992)

    SciTech Connect

    Bollinger, G.A.; Sibol, M.S.; Chapman, M.C.; Snoke, J.A.

    1993-07-01

    In 1986, the Virginia Regional Seismic Network was one of the few fully calibrated digital seismic networks in the United States. Continued operation has resulted in the archival of signals from 2,000+ local, regional and teleseismic sources. Seismotectonic studies of the central Virginia seismic zone showed the activity in the western part to be related to a large antiformal structure while seismicity in the eastern portion is associated spatially with dike swarms. The eastern Tennessee seismic zone extends over a 300x50 km area and is the result of a compressive stress field acting at the intersection between two large crustal blocks. Hydroseismicity, which proposes a significant role for meteoric water in intraplate seismogenesis, found support in the observation of common cyclicities between streamflow and earthquake strain data. Seismic hazard studies have provided the following results: (1) Damage areas in the eastern United States are three to five times larger than those observed in the west. (2) Judged solely on the basis of cataloged earthquake recurrence rates, the next major shock in the southeast region will probably occur outside the Charleston, South Carolina area. (3) Investigations yielded necessary hazard parameters (for example, maximum magnitudes) for several sites in the southeast. Basic to these investigations was the development and maintenance of several seismological data bases.

  5. A future for drifting seismic networks

    NASA Astrophysics Data System (ADS)

    Simons, F. J.; Nolet, G.; Babcock, J.

    2007-12-01

    One-dimensional, radial Earth models are sufficiently well constrained to accurately locate earthquakes and calculate the paths followed by seismic rays. The differences between observations and theoretical predictions of seismograms in such Earth models can be used to reconstruct the three-dimensional wave speed distribution in the regions sampled by the seismic waves, by the technique of seismic tomography. Caused by thermal, compositional, and textural variations, wave speed anomalies remain the premier data source to fully understand the structure and evolution of our planet, from the scale of mantle convection and the mechanisms of heat transfer from core to surface to the international between the deep Earth and surface processes such as plate motion and crustal deformation. Unequal geographical data coverage continues to fundamentally limit the quality of tomographic reconstructions of seismic wave speeds in the interior of the Earth. Only at great cost can geophysicists overcome the difficulties of placing seismographs on the two thirds of the Earth's surface that is covered by oceans. The lack of spatial data coverage strongly hampers the determination of the structure of the Earth in the uncovered regions: all 3-D Earth models are marked by blank spots in areas, distributed throughout the Earth, where little or no information can be obtained. As a possible solution to gaining equal geographic data coverage, we have developed MERMAID, a prototype mobile receiver that could provide an easy, cost-effective way to collect seismic data in the ocean. It is a modification of the robotic floating instruments designed and used by oceanographers. Like them, MERMAID spends its life at depth but is capable of surfacing using a pump and bladder. We have equipped it with a hydrophone to record water pressure variations induced by compressional (P) waves. Untethered and passively drifting, such a floating seismometer will surface upon detection of a "useful" seismic

  6. Use of an Educational Seismic Network for Monitoring Intraplate Seismicity in the Central United States

    NASA Astrophysics Data System (ADS)

    Webb, S. M.; Bailey, L.; Lindsey, J.; Pavlis, G. L.; Hamburger, M. W.; Bauer, M.

    2006-12-01

    The Indiana PEPP seismic network is a 21-station broadband, digital seismic network operated as a collaboration between Indiana University and area high schools, colleges, and museums. Since 1999 the network has used internet data transmission to provide real-time network recording and archiving at the IRIS Data Management Center. The network provides expanded coverage of intraplate seismicity, quarry and mining explosion, and teleseismic earthquakes. We analyzed the signal-to-noise ratio for 11 local events tabulated in the ANSS catalog and used this to project the detection threshold for the network. We define a detection threshold for these events as the minimum projected equivalent event with 5 phases having a signal to noise ration of 3 or larger. We found that the detection threshold for events in southern Indiana, which is the approximate center of the network, varied from 1.7 to 2.3. For events outside this area the estimated detection floor ranges from 2.5 to 3.3. We also examined 264 regional earthquakes (300 to 1500 km) tabulated in the ANSS catalog during 2002. We found events larger than approximately 2.5 in the New Madrid region were consistently detectable. Regional events larger than 3.0 in the 700 to 1500 km distance range were consistently recorded. To further clarify detection capabilities we carefully scanned all data from a 114- day period, from day 51 through 164 of 2002. During this test period we observed 3520 mining explosions (29 events/day), all teleseismic events larger than about 5.0, and only 2 unambiguous earthquakes (the June 18, M_L = 5.0, Evansville (Caborn) mainshock and a single aftershock). This result illustrates an important practical issue in appraising seismicity levels in this area: less than 0.1% of the detected signals were local earthquakes. We extended this review period to include the remaining 251 days of 2002, but examining only the nighttime hours (0000-1200 UTC), when the levels of noise and blasting are minimal

  7. Establishing seismic network capabilities in Haïti

    NASA Astrophysics Data System (ADS)

    Clouard, Valerie; Saurel, Jean-Marie; Prepetit, Claude; McNamara, Daniel; Hough, Susan; Saint-Louis, Mildor; Altidor, Jean-Robert

    2014-05-01

    The January 12, 2010 earthquake ruptured a poorly instrumented region that is located on a complex, wide, deformed zone on the boundary between the Caribbean Plate and the North American Plate. This event evidenced the need for a permanent seismic network in Haiti. Immediately after the 2010 earthquake, a strong motion network was deployed by USGS and 3 broadband seismometers were installed by the NRCAN. All this instrumentation is still working, however, it is mainly located around Port-au-Prince. In 2011, the UTS (Technical Unit of Seismology) was created by the BME (Mining and Energy Bureau) to take in charge the seismic monitoring of the national territory and a Memorandum of Understanding was signed with IPGP that would help through its Antilles Volcano and Seismic Observatories. After a 2-month training in Martinique of Haitian operators, Earthworm and Seiscomp3 were installed on the UTS server and neighboring country stations were include to the detection network. To enlarge the seismic networks to the whole territory, 10 broadband seismometers and 6 accelerometers were acquired. With these new stations, which will be installed in 2014 in secured places equipped with internet or VSAT antenna and with network code AY, the seismic performance standards for the detection and analysis of earthquakes change: 1) Earthquake detection from 30 seconds to 10, 2) Minimum magnitude threshold from M3.8 to M2.8, and 3) Initial hypocenter error from 5km to less than 2 km. The remaining efforts should focus on permanent and qualified human resources to maintain these networks.

  8. Seismicity characteristics in the southeastern Central Range of Taiwan from a temporary seismic network

    NASA Astrophysics Data System (ADS)

    Peng, Guan-Hao; Yen, Horng-Yuan; Kuo-Chen, Hao

    2015-04-01

    Taiwan is located in the boundary between the Philippine Sea and Eurasian plates. The Taiwan orogen is created by the collision between the continental shelf of the Eurasian plate and the oceanic crust of the Philippine Sea plate. Currently, we have deployed a temporary seismic network with new six seismographs that increase density of stations from 10 km away to 5 km away in southeastern Central Range and combined with data from the Central Weather Bureau of Taiwan (CWB) to study the seismicity in this area. Totally, there were 415 earthquakes with good quality of location (ERZ and ERH are less than 5 km) from June to August, 2013. However, in previous studies, our study area was reported as an aseismic zone. With the benefit of the temporary seismic network, we were able to detect micro-earthquakes in this "aseismic zone". Moreover, it is interesting to note that in some stations, volcano-seismic signals like spasmodic bursts are observed and consist of numerous high frequency earthquakes occurring very closely in time, or hybrid seismic signals that have a high frequency sharp P-wave onset with no clear low frequency S-wave phase. This phenomenon can be interpreted as high-temperature and fluid activities in the upper and middle crust (5-20km depth) in this area from previous studies (Wang et al., 2010 and Hsieh et al., 2014)).

  9. Characterizing North Texas Seismicity with a High Density Network of Exploration Seismic Reflection Recorders

    NASA Astrophysics Data System (ADS)

    Hayward, C.; Barklage, M.; Hollis, D.; DeShon, H. R.; Magnani, M. B.

    2014-12-01

    A series of low magnitude earthquakes in North Texas near Azle, Texas began 5-Nov 2013 and continues to the present. By 3-Jan 2014, hypocenters based on a temporary local network were sufficiently well defined to plan an experiment using a dense network near the epicenters. On 25-Feb 2014, NodalSeismic in cooperation with Southern Methodist University, installed and operated 130 vertical 10 Hz recorders distributed along three lines within a few km of the epicenters and collected 10 days of continuous seismic recording at 500 samples/second. Data was converted from SEGD to standard earthquake seismological formats (SEED) for processing.During the time of the high density recording, relatively few events in the Azle area were detected by the 12 station local network; however, correlation processing on the dense network detected over 100 events. In addition regional events from local quarries as well as a teleseism were well recorded. One of the 10Hz recorders was within 50m of a 1 Hz vertical seismometer, providing the ability to evaluate the utility of the high frequency geophones for recording broader band signals. By comparing catalogs from the local network with detection lists from the high density network, the detection threshold for the augmented network is determined. Delta time offsets for the teleseismic signal may be used to determine relative station corrections (static offsets) prior to fitting classical hyperbola to a velocity model and to estimate epicenters. Comparison between dense network location results and results using standard techniques on the 12 station local network provides an assessment of the utility of this high density technique to quickly evaluate areas where induced seismicity is suspected. Finally, the method provides an opportunity to compare background noise levels between the rapidly installed low cost exploration systems and the more carefully deployed local network.

  10. The LUSI Seismic Experiment: Deployment of a Seismic Network around LUSI, East Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Karyono, Karyono; Mazzini, Adriano; Lupi, Matteo; Syafri, Ildrem; Haryanto, Iyan; Masturyono, Masturyono; Hadi, Soffian; Rohadi, Suprianto; Suardi, Iman; Rudiyanto, Ariska; Pranata, Bayu

    2015-04-01

    The spectacular Lusi eruption started in northeast Java, Indonesia the 29 of May 2006 following a M6.3 earthquake striking the island. Initially, several gas and mud eruption sites appeared along the reactivated strike-slip Watukosek fault system and within weeks several villages were submerged by boiling mud. The most prominent eruption site was named Lusi. Lusi is located few kilometres to the NE of the Arjuno-Welirang volcanic complex. Lusi sits upon the Watukosek fault system. From this volcanic complex originates the Watukosek fault system that was reactivated by the M6.3 earthquake in 2006 and is still periodically reactivated by the frequent seismicity. To date Lusi is still active and erupting gas, water, mud and clasts. Gas and water data show that the Lusi plumbing system is connected with the neighbouring Arjuno-Welirang volcanic complex. This makes the Lusi eruption a "sedimentary hosted geothermal system". To verify and characterise the occurrence of seismic activity and how this perturbs the connected Watukosek fault, the Arjuno-Welirang volcanic system and the ongoing Lusi eruption, we deployed 30 seismic stations (short-period and broadband) in this region of the East Java basin. The seismic stations are more densely distributed around LUSI and the Watukosek fault zone that stretches between Lusi and the Arjuno Welirang (AW) complex. Fewer stations are positioned around the volcanic arc. Our study sheds light on the seismic activity along the Watukosek fault system and describes the waveforms associated to the geysering activity of Lusi. The initial network aims to locate small event that may not be captured by the Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG) seismic network and it will be crucial to design the second phase of the seismic experiment that will consist of a local earthquake tomography of the Lusi-Arjuno Welirang region and temporal variations of vp/vs ratios. Such variations will then be ideally related to

  11. Structural Geology of the Northwestern Portion of Los Alamos National Laboratory, Rio Grande Rift, New Mexico: Implications for Seismic Surface Rupture Potential from TA-3 to TA-55

    SciTech Connect

    Jamie N. Gardner: Alexis Lavine; Giday WoldeGabriel; Donathon Krier; David Vaniman; Florie Caporuscio; Claudia Lewis; Peggy Reneau; Emily Kluk; M. J. Snow

    1999-03-01

    Los Alamos National Laboratory lies at the western boundary of the Rio Grande rift, a major tectonic feature of the North American Continent. Three major faults locally constitute the modem rift boundary, and each of these is potentially seismogenic. In this study we have gathered structural geologic data for the northwestern portion of Los Alamos National Laboratory through high-precision geologic mapping, conventional geologic mapping, stratigraphic studies, drilling, petrologic studies, and stereographic aerial photograph analyses. Our study area encompasses TA-55 and TA-3, where potential for seismic surface rupture is of interest, and is bounded on the north and south by the townsite of Los Alamos and Twomile Canyon, respectively. The study area includes parts of two of the potentially active rift boundary faults--the Pajarito and Rendija Canyon faults-that form a large graben that we name the Diamond Drive graben. The graben embraces the western part of the townsite of Los Alamos, and its southern end is in the TA-3 area where it is defined by east-southeast-trending cross faults. The cross faults are small, but they accommodate interactions between the two major fault zones and gentle tilting of structural blocks to the north into the graben. North of Los Alamos townsite, the Rendija Canyon fault is a large normal fault with about 120 feet of down-to-the-west displacement over the last 1.22 million years. South from Los Alamos townsite, the Rendija Canyon fault splays to the southwest into a broad zone of deformation. The zone of deformation is about 2,000 feet wide where it crosses Los Alamos Canyon and cuts through the Los Alamos County Landfill. Farther southwest, the fault zone is about 3,000 feet wide at the southeastern corner of TA-3 in upper Mortandad Canyon and about 5,000 feet wide in Twomile Canyon. Net down-to-the-west displacement across the entire fault zone over the last 1.22 million years decreases to the south as the fault zone broadens as

  12. Recent Progress of Seismic Observation Networks in Japan

    NASA Astrophysics Data System (ADS)

    Okada, Y.

    2013-04-01

    Before the occurrence of disastrous Kobe earthquake in 1995, the number of high sensitivity seismograph stations operated in Japan was nearly 550 and was concentrated in the Kanto and Tokai districts, central Japan. In the wake of the Kobe earthquake, Japanese government has newly established the Headquarters for Earthquake Research Promotion and started the reconstruction of seismic networks to evenly cover the whole Japan. The basic network is composed of three seismographs, i.e. high sensitivity seismograph (Hi-net), broadband seismograph (F-net), and strong motion seismograph (K-NET). A large majority of Hi-net stations are also equipped with a pair of strong motion sensors at the bottom of borehole and the ground surface (KiK-net). A plenty of high quality data obtained from these networks are circulated at once and is producing several new seismological findings as well as providing the basis for the Earthquake Early Warning system. In March 11, 2011, "Off the Pacific coast of Tohoku Earthquake" was generated with magnitude 9.0, which records the largest in the history of seismic observation in Japan. The greatest disaster on record was brought by huge tsunami with nearly 20 thousand killed or missing people. We are again noticed that seismic observation system is quite poor in the oceanic region compared to the richness of it in the inland region. In 2012, NIED has started the construction of ocean bottom seismic and tsunami observation network along the Japan Trench. It is planned to layout 154 stations with an average spacing of 30km, each of which is equipped with an accelerometer for seismic observation and a water pressure gauge for tsunami observation. We are expecting that more rapid and accurate warning of earthquake and tsunami becomes possible by this observing network.

  13. Building an educational seismic network in Romanian schools

    NASA Astrophysics Data System (ADS)

    Zaharia, Bogdan; Tataru, Dragos; Grecu, Bogdan; Ionescu, Constantin; Bican-Brisan, Nicoleta; Neagoe, Cristian

    2014-05-01

    Understanding the earthquake phenomena and their effects is an important step toward the education of population and aims to raise the awareness about the earthquake risk and possible mitigation actions. In this sense, The Romanian Educational Seismic Network project represents an efficient communication tool, allowing teaching and learning about the earthquakes and seismic wave impact through experimental practices and educational activities. The seismic network consist of nine SEP seismometers installed in high-schools from the most important seismic areas (Vrancea, Banat, Făgăraş, Dobrogea), vulnerable cities (Bucharest, Iasi) or high populated places (Cluj, Sibiu, Timisoara, Zalău) and is coordinated by the National Institute of Earth Physics from Bucharest. Once installed, the seismic network is the starting point of activities for students through an e-learning platform. Some objectives are aimed: - To train students and teachers how to make analysis and interpretation of seismological data; - To make science more interesting for students; - To improve the participation rates in physical sciences for students; - To raise awareness of geoscience as a scientific discipline for pre-university students; - To promote the installation and effective use of educational seismographs and seismic data; - To reinforce and develop relationships between participating schools and research institutes; - To create an earthquake database this will be used by students and teachers for educational purposes. Different types of practical activities using educational seismometer, designed by researchers for students, are described in educational materials and in the web platform project. Also we encourage the teachers from the participating schools to share their experiences and produce new didactic tools for the classroom. This collaborative work could illustrate the conjugated efforts of researchers and teachers for a better education and awareness of the risk culture

  14. Automatic classification of seismic events within a regional seismograph network

    NASA Astrophysics Data System (ADS)

    Tiira, Timo; Kortström, Jari; Uski, Marja

    2015-04-01

    A fully automatic method for seismic event classification within a sparse regional seismograph network is presented. The tool is based on a supervised pattern recognition technique, Support Vector Machine (SVM), trained here to distinguish weak local earthquakes from a bulk of human-made or spurious seismic events. The classification rules rely on differences in signal energy distribution between natural and artificial seismic sources. Seismic records are divided into four windows, P, P coda, S, and S coda. For each signal window STA is computed in 20 narrow frequency bands between 1 and 41 Hz. The 80 discrimination parameters are used as a training data for the SVM. The SVM models are calculated for 19 on-line seismic stations in Finland. The event data are compiled mainly from fully automatic event solutions that are manually classified after automatic location process. The station-specific SVM training events include 11-302 positive (earthquake) and 227-1048 negative (non-earthquake) examples. The best voting rules for combining results from different stations are determined during an independent testing period. Finally, the network processing rules are applied to an independent evaluation period comprising 4681 fully automatic event determinations, of which 98 % have been manually identified as explosions or noise and 2 % as earthquakes. The SVM method correctly identifies 94 % of the non-earthquakes and all the earthquakes. The results imply that the SVM tool can identify and filter out blasts and spurious events from fully automatic event solutions with a high level of confidence. The tool helps to reduce work-load in manual seismic analysis by leaving only ~5 % of the automatic event determinations, i.e. the probable earthquakes for more detailed seismological analysis. The approach presented is easy to adjust to requirements of a denser or wider high-frequency network, once enough training examples for building a station-specific data set are available.

  15. The Great Maule earthquake: seismicity prior to and after the main shock from amphibious seismic networks

    NASA Astrophysics Data System (ADS)

    Lieser, K.; Arroyo, I. G.; Grevemeyer, I.; Flueh, E. R.; Lange, D.; Tilmann, F. J.

    2013-12-01

    The Chilean subduction zone is among the seismically most active plate boundaries in the world and its coastal ranges suffer from a magnitude 8 or larger megathrust earthquake every 10-20 years. The Constitución-Concepción or Maule segment in central Chile between ~35.5°S and 37°S was considered to be a mature seismic gap, rupturing last in 1835 and being seismically quiet without any magnitude 4.5 or larger earthquakes reported in global catalogues. It is located to the north of the nucleation area of the 1960 magnitude 9.5 Valdivia earthquake and to the south of the 1928 magnitude 8 Talca earthquake. On 27 February 2010 this segment ruptured in a Mw=8.8 earthquake, nucleating near 36°S and affecting a 500-600 km long segment of the margin between 34°S and 38.5°S. Aftershocks occurred along a roughly 600 km long portion of the central Chilean margin, most of them offshore. Therefore, a network of 30 ocean-bottom-seismometers was deployed in the northern portion of the rupture area for a three month period, recording local offshore aftershocks between 20 September 2010 and 25 December 2010. In addition, data of a network consisting of 33 landstations of the GeoForschungsZentrum Potsdam were included into the network, providing an ideal coverage of both the rupture plane and areas affected by post-seismic slip as deduced from geodetic data. Aftershock locations are based on automatically detected P wave onsets and a 2.5D velocity model of the combined on- and offshore network. Aftershock seismicity analysis in the northern part of the survey area reveals a well resolved seismically active splay fault in the accretionary prism of the Chilean forearc. Our findings imply that in the northernmost part of the rupture zone, co-seismic slip most likely propagated along the splay fault and not the subduction thrust fault. In addition, the updip limit of aftershocks along the plate interface can be verified to about 40 km landwards from the deformation front. Prior to

  16. optimization of seismic network design: application to a geophysical international lunar network

    NASA Astrophysics Data System (ADS)

    Yamada, R.; Garcia, R. F.; Lognonne, P.; Calvet, M.; Gagnepain-Beyneix, J.; Le Feuvre, M.

    2010-12-01

    During the next decade, some lunar seismic experiments are planned under the international lunar network initiative, such as NASA ILN Anchor nodes mission or Lunette DISCOVERY proposal, JAXA SELENE-2 and LUNA-GLOB penetrator missions, during which 1 to 4 seismic stations will be deployed on the lunar surface. Yamada et al. (submitted) have described how to design the optimized network in order to obtain the best scientific gain from these future lunar landing missions. In this presentation, we will describe the expected gain from the new lunar seismic observations potentially obtained by the optimized network compared with past Apollo seismic experiments. From the Apollo seismic experiments, valuable information about the lunar interior structure was obtained using deep and shallow moonquakes, and meteoroid impacts (e.g., Nakamura et al., 1983, Lognonné et al., 2003). However, due to the limited sensitivity of Apollo lunar seismometers and the narrowness of the seismic network, the deep lunar structure, especially the core, was not properly retrieved. In addition, large uncertainties are associated with the inferred crustal thickness around the Apollo seismic stations. Improvements of these knowledge will help us to understand the origin of the Earth-Moon system and the initial differentiation of the Moon. Therefore, we have studied the optimization of a seismic network consisting of three or four new seismometers in order to place better constraints on the lunar mantle structure and /or crustal thickness. The network is designed to minimize the a posteriori errors and maximize the resolution of the velocity perturbations inside the mantle and /or the crust through a linear inverse method. For the inversion, the deep moonquakes from active sources already located by Apollo seismic data are used, because it is known that these events occur repeatedly at identical nests depending on tidal constraints. In addition, we use randomly distributed meteoroid impacts

  17. The performance of the stations of the Romanian seismic network in monitoring the local seismic activity

    NASA Astrophysics Data System (ADS)

    Ardeleanu, Luminita Angela; Neagoe, Cristian

    2014-05-01

    The seismic survey of the territory of Romania is mainly performed by the national seismic network operated by the National Institute for Earth Physics of Bucharest. After successive developments and upgrades, the network consists at present of 123 permanent stations equipped with high quality digital instruments (Kinemetrics K2, Quantera Q330, Quantera Q330HR, PS6-24 and Basalt digitizers) - 102 real time and 20 off-line stations - which cover the whole territory of the country. All permanent stations are supplied with 3 component accelerometers (episenzor type), while the real time stations are in addition provided with broadband (CMG3ESP, CMG40T, KS2000, KS54000, KS2000, CMG3T, STS2) or short period (SH-1, S13, Mark l4c, Ranger, GS21, L22_VEL) velocity sensors. Several communication systems are currently used for the real time data transmission: an analog line in UHF band, a line through GPRS (General Packet Radio Service), a dedicated line through satellite, and a dedicated line provided by the Romanian Special Telecommunication Service. During the period January 1, 2006 - June 30, 2013, 5936 shallow depth seismic events - earthquakes and quarry blasts - with local magnitude ML ≥ 1.2 were localized on the Romanian territory, or in its immediate vicinity, using the records of the national seismic network; 1467 subcrustal earthquakes (depth ≥ 60 km) with magnitude ML ≥ 1.9 were also localized in the Vrancea region, at the bend of the Eastern Carpathians. The goal of the present study is to evaluate the individual contribution of the real time seismic stations to the monitoring of the local seismicity. The performance of each station is estimated by taking into consideration the fraction of events that are localised using the station records, compared to the total number of events of the catalogue, occurred during the time of station operation. Taking into account the nonuniform space distribution of earthquakes, the location of the site and the recovery

  18. Determination of trajectories of fireballs using seismic network data

    NASA Astrophysics Data System (ADS)

    Ishihara, Y.

    2006-12-01

    Fireballs, Bolides, which are caused by high velocity passages of meteoroids through the atmosphere, generate shockwaves. Meteor shockwave provide us very important information (arrival time and amplitude) to study meteor physics. The shockwave arrival time data enable us to determine trajectories of the fireballs. On the other hand, the shockwave amplitude tells us size and ablation history of the meteoroid. Infrasound observation is one of the ways of detecting bolide shockwaves. However, we have no infrasound observational networks extends for large area with enough spatial distribution for determination of trajectories and estimate ablation histories. We have only a few infrasound arrays that have three or four elements, in the Japanese islands. Last decade, digital seismic networks are greatly improved for the purpose of monitoring micro earthquakes. Those seismic networks are quite sensitive for detecting micro ground vibration, and then those networks could detect not only seismic wave generated by earthquakes, but also ground oscillations generated by coupling of meteor shockwave with the ground near station. Last years, I analyses this kind of ground motion data recorded by seismic network, as meteor shockwave signals. For example, we estimate some great fireball's aerial path from arrival times of shockwaves (e.g., Ishihara et. al., 2003 Earth Planets, and Space, 2004 Geophysical Research. Letters.; Pujol et al., 2006 Planetary and Space Science), and we estimate sizes and ablation history of some great fireball and a meteorite fall (Ishihara et al., 2004 Meteoroids2004). In Japan, some great fireball falls occurred during 2004 to 2005. In this presentation, I show the trajectories of these fireballs determined from shockwave analysis. Some fireballs trajectories are also determined from photographic records. The trajectories determined from shockwave and that from photos show good agreement.

  19. The improved broadband Real-Time Seismic Network in Romania

    NASA Astrophysics Data System (ADS)

    Neagoe, C.; Ionescu, C.

    2009-04-01

    Starting with 2002 the National Institute for Earth Physics (NIEP) has developed its real-time digital seismic network. This network consists of 96 seismic stations of which 48 broad band and short period stations and two seismic arrays are transmitted in real-time. The real time seismic stations are equipped with Quanterra Q330 and K2 digitizers, broadband seismometers (STS2, CMG40T, CMG 3ESP, CMG3T) and strong motions sensors Kinemetrics episensors (+/- 2g). SeedLink and AntelopeTM (installed on MARMOT) program packages are used for real-time (RT) data acquisition and exchange. The communication from digital seismic stations to the National Data Center in Bucharest is assured by 5 providers (GPRS, VPN, satellite communication, radio lease line and internet), which will assure the back-up communications lines. The processing centre runs BRTT's AntelopeTM 4.10 data acquisition and processing software on 2 workstations for real-time processing and post processing. The Antelope Real-Time System is also providing automatic event detection, arrival picking, event location and magnitude calculation. It provides graphical display and reporting within near-real-time after a local or regional event occurred. Also at the data center was implemented a system to collect macroseismic information using the internet on which macro seismic intensity maps are generated. In the near future at the data center will be install Seiscomp 3 data acquisition processing software on a workstation. The software will run in parallel with Antelope software as a back-up. The present network will be expanded in the near future. In the first half of 2009 NIEP will install 8 additional broad band stations in Romanian territory, which also will be transmitted to the data center in real time. The Romanian Seismic Network is permanently exchanging real -time waveform data with IRIS, ORFEUS and different European countries through internet. In Romania, magnitude and location of an earthquake are now

  20. Seismic event classification using Self-Organizing Neural Networks

    SciTech Connect

    Maurer, W.J.; Dowla, F.U.; Jarpe, S.P.

    1991-10-15

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. We have studied Self Organizing Neural Networks (SONNs) for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs were developed and tested with a moderately large set of real seismic events. Given the detection of a seismic event and the corresponding signal, we compute the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This preprocessed input is fed into the SONNs. The overall results based on 111 events (43 training and 68 test events) show that SONNs are able to group events that ``look`` similar. We also find that the ART algorithm has an advantage in that the types of cluster groups do not need to be predefined. When a new type of event is detected, the ART network is able to handle the event rather gracefully. The results from the SONNs together with an expert seismologist`s classification are then used to derive event classification probabilities. A strategy to integrate a SONN into the interpretation of seismic events is also proposed.

  1. Temporary seismic networks on active volcanoes of Kamchatka (Russia)

    NASA Astrophysics Data System (ADS)

    Jakovlev, Andrey; Koulakov, Ivan; Abkadyrov, Ilyas; Shapiro, Nikolay; Kuznetsov, Pavel; Deev, Evgeny; Gordeev, Evgeny; Chebrov, Viktor

    2016-04-01

    We present details of four field campaigns carried out on different volcanoes of Kamchatka in 2012-2015. Each campaign was performed in three main steps: (i) installation of the temporary network of seismic stations; (ii) autonomous continuous registration of three component seismic signal; (III) taking off the network and downloading the registered data. During the first campaign started in September 2012, 11 temporary stations were installed over the Avacha group of volcanoes located 30 km north to Petropavlovsk-Kamchatsky in addition to the seven permanent stations operated by the Kamchatkan Branch of the Geophysical Survey (KBGS). Unfortunately, with this temporary network we faced with two obstacles. The first problem was the small amount of local earthquakes, which were detected during operation time. The second problem was an unexpected stop of several stations only 40 days after deployment. Nevertheless, after taking off the network in August 2013, the collected data appeared to be suitable for analysis using ambient noise. The second campaign was conducted in period from August 2013 to August 2014. In framework of the campaign, 21 temporary stations were installed over Gorely volcano, located 70 km south to Petropavlovsk-Kamchatsky. Just in time of the network deployment, Gorely Volcano became very seismically active - every day occurred more than 100 events. Therefore, we obtain very good dataset with information about thousands of local events, which could be used for any type of seismological analysis. The third campaign started in August 2014. Within this campaign, we have installed 19 temporary seismic stations over Tolbachik volcano, located on the south side of the Klyuchevskoy volcano group. In the same time on Tolbachik volcano were installed four temporary stations and several permanent stations operated by the KBGS. All stations were taking off in July 2015. As result, we have collected a large dataset, which is now under preliminary analysis

  2. Towards the Establishment of the Hawaii Integrated Seismic Network for Tsunami, Seismic, and Volcanic Hazard Mitigation

    NASA Astrophysics Data System (ADS)

    Shiro, B. R.; Koyanagi, S. K.; Okubo, P. G.; Wolfe, C. J.

    2006-12-01

    The NOAA Pacific Tsunami Warning Center (PTWC) located in `Ewa Beach, Hawai`i, provides warnings to the State of Hawai`i regarding locally generated tsunamis. The USGS Hawaiian Volcano Observatory (HVO) located in Hawai`i National Park monitors earthquakes on the island of Hawai`i in order to characterize volcanic and earthquake activity and hazards. In support of these missions, PTWC and HVO operate seismic networks for rapidly detecting and evaluating earthquakes for their tsunamigenic potential and volcanic risk, respectively. These existing seismic networks are comprised mostly of short-period vertical seismometers with analog data collection and transmission based on decades-old technology. The USGS National Strong Motion Program (NSMP) operates 31 accelerometers throughout the state, but none currently transmit their data in real time. As a result of enhancements to the U.S. Tsunami Program in the wake of the December 2004 Indian Ocean tsunami disaster, PTWC is upgrading and expanding its seismic network using digital real-time telemetry from broadband and strong motion accelerometer stations. Through new cooperative agreements with partners including the USGS (HVO and NSMP), IRIS, University of Hawai`i, and Germany's GEOFON, the enhanced seismic network has been designed to ensure maximum benefit to all stakeholders. The Hawaii Integrated Seismic Network (HISN) will provide a statewide resource for tsunami, earthquake, and volcanic warnings. Furthermore, because all data will be archived by the IRIS Data Management Center (DMC), the HISN will become a research resource to greater scientific community. The performance target for the enhanced HISN is for PTWC to provide initial local tsunami warnings within 90 seconds of the earthquake origin time. This will be accomplished using real-time digital data transmission over redundant paths and by implementing contemporary analysis algorithms in real-time and near-real-time. Earthquake location, depth, and

  3. Intraplate seismicity across the Cape Verde swell: A contribution from a temporary seismic network

    NASA Astrophysics Data System (ADS)

    Vales, Dina; Dias, Nuno A.; Rio, Inês; Matias, Luís; Silveira, Graça; Madeira, José; Weber, Michael; Carrilho, Fernando; Haberland, Christian

    2014-12-01

    We present an analysis and characterization of the regional seismicity recorded by a temporary broadband seismic network deployed in the Cape Verde archipelago between November 2007 and September 2008. The detection of earthquakes was based on spectrograms, allowing the discrimination from low-frequency volcanic signals, resulting in 358 events of which 265 were located, the magnitudes usually being smaller than 3. For the location, a new 1-D P-velocity model was derived for the region showing a crust consistent with an oceanic crustal structure. The seismicity is located mostly offshore the westernmost and geologically youngest areas of the archipelago, near the islands of Santo Antão and São Vicente in the NW and Brava and Fogo in the SW. The SW cluster has a lower occurrence rate and corresponds to seismicity concentrated mainly along an alignment between Brava and the Cadamosto seamount presenting normal faulting mechanisms. The existence of the NW cluster, located offshore SW of Santo Antão, was so far unknown and concentrates around a recently recognized submarine cone field; this cluster presents focal depths extending from the crust to the upper mantle and suggests volcanic unrest. No evident temporal behaviour could be perceived, although the events tend to occur in bursts of activity lasting a few days. In this recording period, no significant activity was detected at Fogo volcano, the most active volcanic edifice in Cape Verde. The seismicity characteristics point mainly to a volcanic origin. The correlation of the recorded seismicity with active volcanic structures agrees with the tendency for a westward migration of volcanic activity in the archipelago as indicated by the geologic record.

  4. Regional Seismic Test Network (RSTN) operations final report

    SciTech Connect

    Harrer, S.J.

    1989-08-01

    This Regional Seismic Test Network (RSTN) Operations Final Report is a history of the operations of this project. It is intended for those who were directly involved in the RSTN project, as well as for those who are involved in other similar projects. Included is a history of problems experienced at each station, functions performed by the System Control and Receiving Station (SCARS), and the performance of some crucial equipment. 9 refs.

  5. Cooperative Development of the Pakistan Seismic Network System (PSNS)

    NASA Astrophysics Data System (ADS)

    Detweiler, S.; Mooney, W.; McDonald, S.

    2005-12-01

    We propose to cooperate with the Pakistan Meteorological Department for the design and construction of the new Pakistan Seismic Network System (PSNS) that has been funded by the government of Pakistan. The PSNS will consist of 12-15 broadband stations, 50 short-period stations, and 50 accelerometers. Our role will be to provide technical assistance in site selection, to prepare the Request for Proposals (RFP) from industry, and to evaluate performance. The relative importance of tsunami warnings, national earthquake and landslide hazards, and whether a largely urban or truly national network is envisioned will be determined early in the program. Final placement of stations will take many factors into consideration including proximity to faults and seismic activity, geographic accessibility, the consistency of bedrock, and various cultural or social effects. This cooperation has the potential to lead to the development of a desperately needed tsunami early warning network that could protect the Pakistani coastal population in the event of a natural disaster such as the Dec. 26, 2004 Sumatra earthquake and tsunami. The seismic hazard off the coast of Pakistan is high due to the proximity of the Makran and Sumatra subduction zones, the former of which could trigger tsunamis in Pakistan with heights of 12m within minutes. In addition to monitoring earthquake activity, the PSNS will provide seismic data of interest to the world-wide scientific community for a region in which there is little understanding of the upper crust and mantle. It will furthermore address educational outreach and diplomacy issues by providing training to Pakistani scientists in routine network operation and data processing.

  6. The Mexican Seismic Network (Red Sísmica Mexicana)

    NASA Astrophysics Data System (ADS)

    Valdes-Gonzales, C. M.; Arreola-Manzano, J.; Castelan-Pescina, G.; Alonso-Rivera, P.; Saldivar-Rangel, M. A.; Rodriguez-Arteaga, O. O.; Lopez-Lena-Villasana, R.

    2014-12-01

    The Mexican Seismic Network (Red Sísmica Mexicana) was created to give sufficient information and opportune to make decisions in order to mitigate seismic and tsunami risk. This was a Mexican government initiative headed by CENAPRED (National Disaster Prevention Center) who made an effort to integrated academic institutions and civil agencies to work together through a collaboration agreement. This network is supported by Universidad National Autónoma de México (UNAM) and its seismic networks (Broad Band and Strong Motion), the Centro de Instrumentación y Registro Sismico (CIRES) with its Earthquake Early Warning System that covers the Guerrero Gap and Oaxaca earthquakes, The Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) with the support of its expertise in tsunami observation and the Secretaria de Marina (SEMAR) to monitor the sea level and operate the Mexican Tsunami Warning Center. The institutions involved in this scope have the compromise to interchange and share the data and advice to the Civil Protection authorities.

  7. Efficiency of a seismic network from the viewpoint of mathematical information theory: application to the Andalucia (Spain) seismic network

    NASA Astrophysics Data System (ADS)

    Lana, X.; Martínez, M. D.; Miguel, F. De

    1990-05-01

    Concepts of information theory applied to data from the Andalucia (Spain) seismic network permit the discussion of whether data are correctly used in determining epicentres. The elementary definition of Shannon's information allows a discussion of the coverage of the epicentres in terms of azimuths and distances to the seismic stations. The contributions of all the stations of the network to the coverage is also investigated. Data were obtained from 13 seismic stations and 765 epicentral determinations corresponding to the seismic activity of the years 1983-84 and some months of 1985 in the Central Belies area (Southern Spain). Information theory concepts were applied to the data after a distribution of epicentres according to their mo values and hypocentral depths. The obtained results show a better treatment of very shallow earthquakes, especially of those with values of mb less than or equal to 2.5. No significant different coverages were obtained for the sets of earthquakes classified according to their hypocentral depths and mb values.

  8. Seismicity and Seismotectonics in the Himalaya of Bhutan: Insights from the GANSSER Seismic Network

    NASA Astrophysics Data System (ADS)

    Diehl, T.; Singer, J.; Hetényi, G.; Kissling, E. H.; Clinton, J. F.

    2014-12-01

    The seismicity of Bhutan is characterized by the apparent lack of great earthquakes and a significantly lower activity compared to most other parts of the Himalayan arc. To better understand the underlying mechanisms of this anomalously low activity and to relate it with possible along-strike differences in the structure of the orogenic belt, a temporary network with 38 broadband seismometers was installed in the Kingdom of Bhutan between January 2013 and April 2014. In this work we present a first catalog of local and regional earthquakes detected and located with the GANSSER (Geodynamics ANd Seismic Structure of the Eastern-Himalaya Region) network. Events were automatically detected using STA/LTA triggers with a global 1-D velocity model. A subset of more than 800 automatic locations were manually reviewed and more than 400 events in Bhutan and surrounding regions have been manually repicked and accurately relocated. Magnitudes of these hypocenters range from ML 0.5 to 5.6. Seismicity along the Main Frontal and Main Boundary Thrusts in south-central Bhutan is very low. The highest activity is clustered along a NE-SW oriented structure in southwest Bhutan, which might be associated with the Goalpara lineament. In eastern Bhutan a cluster of seismicity is identified in the vicinity of the 2009 Mw=6.2 event and the embayment of the Main Central Thrust, near the town of Mongar. For two events in Bhutan a moment tensor was derived. Both solutions indicate strike-slip mechanisms and an Mw of 3.9 and 4.0. The majority of well-constrained focal depths ranges between 10 to 30 km and might be associated with the Main Himalayan Thrust (MHT). One exception is the Mw=4.0 event in northern Bhutan in June 2013, which occurred at about 70 km depth, most likely in the underthrusting Indian lower crust. To further improve the accuracy of locations, about 100 events were used to simultaneously invert for seismic velocities and hypocenters. We will discuss possible seismotectonic

  9. The Configurable Seismic Monitoring System (CSMS): Local Seismic Network (LSN) data acquisition user's manual: Version 1. 0

    SciTech Connect

    Peterson, S.J.; Zucca, J.J.; Ewert, D.W.; Moccia, D.J.; Rock, D.W.; Stager, R.K.

    1988-09-01

    The Configurable Seismic Monitoring System (CSMS) is a portable seismograph system that can be used for a variety of applications. In its primary format, the CSMS is the Local Seismic Network (LSN); however, the CSMS could be used for site surveys in advance of installing permanent single stations and arrays. It could also be used for special experiments requiring portable recording equipment. 4 figs.

  10. The 2007 Sumatra seismic sequence revealed by a regional seismic network in Indonesia

    NASA Astrophysics Data System (ADS)

    Nakano, M.; Inoue, H.; Kumagai, H.; Yamashina, T.; Sunarjo; Fauzi; Suhardjono

    2007-12-01

    On September 12, 2007, a great earthquake with Mw 8.4 occurred at 11:10 (UTC) off Bengkulu, Sumatra, Indonesia. This event was followed by a large earthquake with Mw 8.0, which occurred at 23:49 (UTC) on the same day in the northwest of the Mw 8.4 earthquake. Another earthquake with Mw 6.8 occurred off Padang, in the northwest of the second earthquake, at 03:35 (UTC) on the next day. These earthquakes caused dozens of casualties and damage to the buildings in Bengkulu and Padang areas. Tsunami with a hight of 1m was observed in Padang, but no severe damage by tsunami was reported. We have been developing an automated system for rapid source parameter determinations of earthquakes in Indonesia, using data obtained from a broadband seismic network in this country (JISNET). This network is operated by NIED and Indonesia Meteorological and Geophysical Agency (BMG). In our method, the moment function is estimated simultaneously with a centroid moment tensor (CMT) solution based on the waveform inversion carried out in the frequency domain. The source parameters for an earthquake greater than Mw 5 can be determined automatically by our system within 15 minutes after the occurrence of an earthquake. The automatic inversion result is then checked manually. The source parameters of earthquakes that are not determined by the automatic system are also determined manually. The source parameters of the 2007 Sumatra earthquakes were succesfully determined by our system. The estimated focal mechanisms show similar thrust-type faultings, suggesting that these earthquakes occurred in association with the subduction of the Indo-Australian Plate beneath Sumatra Island. Both the Mw 8.4 and 8.0 events occurred at a depth of about 20 km. The rupture durations estimated from the moment functions are 140 s and 108 s for the Mw 8.4 and Mw 8.0 events, respectively. These rupture durations are slightly longer than typical values for earthquakes of these magnitudes. The aftershocks are

  11. Insight into landslide kinematics from a broadband seismic network

    NASA Astrophysics Data System (ADS)

    Lin, Cheng-Horng

    2015-01-01

    The kinematic features of the 2009 Hsiaolin landslide were analyzed using a broadband seismic network in Taiwan. Both the final impact velocity and acceleration of the landslide were calculated based on the traveling distance and time of the landslide. A distance of approximately 2,500 m was observed on the surface, and the time from the initial collapse to the final impact was of 60.38 s according to broadband seismic data recorded nearby. The initial collapse time was determined using very-long-period seismic signals (20 to 50 s) created by the elastic rebound of the shallow crust as the overlying landslide initially moved downhill. The final impact time was determined by detecting the largest amplitudes of high-frequency seismic signals (1 to 10 Hz). The final impact velocity of approximately 298 km/h exhibited by this landslide had never before been recorded and thus might mark a world record; these speeds can be attributed mainly to a low friction coefficient (approximately 0.12) and a long run-out (approximately 2,500 m) along a gentle dip-slope surface (approximately 15°).

  12. 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.

  13. Multiband array detection and location of seismic sources recorded by dense seismic networks

    NASA Astrophysics Data System (ADS)

    Poiata, Natalia; Satriano, Claudio; Vilotte, Jean-Pierre; Bernard, Pascal; Obara, Kazushige

    2016-06-01

    We present a new methodology for detection and space-time location of seismic sources based on multiscale, frequency-selective coherence of the wave field recorded by dense large-scale seismic networks and local antennas. The method is designed to enhance coherence of the signal statistical features across the array of sensors and consists of three steps: signal processing, space-time imaging, and detection and location. The first step provides, for each station, a simplified representation of seismic signal by extracting multiscale non-stationary statistical characteristics, through multiband higher-order statistics or envelopes. This signal processing scheme is designed to account for a priori unknown transients, potentially associated with a variety of sources (e.g. earthquakes, tremors), and to prepare data for a better performance in posterior steps. Following space-time imaging is carried through 3-D spatial mapping and summation of station-pair time-delay estimate functions. This step produces time-series of 3-D spatial images representing the likelihood that each pixel makes part of a source. Detection and location is performed in the final step by extracting the local maxima from the 3-D spatial images. We demonstrate the efficiency of the method in detecting and locating seismic sources associated with low signal-to-noise ratio on an example of the aftershock earthquake records from local stations of International Maule Aftershock Deployment in Central Chile. The performance and potential of the method to detect, locate and characterize the energy release associated with possibly mixed seismic radiation from earthquakes and low-frequency tectonic tremors is further tested on continuous data from southwestern Japan.

  14. Multi-band array detection and location of seismic sources recorded by dense seismic networks

    NASA Astrophysics Data System (ADS)

    Poiata, Natalia; Satriano, Claudio; Vilotte, Jean-Pierre; Bernard, Pascal; Obara, Kazushige

    2016-02-01

    We present a new methodology for detection and space-time location of seismic sources based on multi-scale, frequency-selective coherence of the wave field recorded by dense large-scale seismic networks and local antennas. The method is designed to enhance coherence of the signal statistical features across the array of sensors and consists of three steps: signal processing, space-time imaging, and detection and location. The first step provides, for each station, a simplified representation of seismic signal by extracting multi-scale non-stationary statistical characteristics, through multi-band higher-order statistics or envelopes. This signal processing scheme is designed to account for a priori unknown transients, potentially associated with a variety of sources (e.g., earthquakes, tremors), and to prepare data for a better performance in posterior steps. Following space-time imaging is carried through 3D spatial mapping and summation of station-pair time-delay estimate functions. This step produces time series of 3D spatial images representing the likelihood that each pixel makes part of a source. Detection and location is performed in the final step by extracting the local maxima from the 3D spatial images. We demonstrate the efficiency of the method in detecting and locating seismic sources associated with low signal-to-noise ratio on an example of the aftershock earthquake records from local stations of International Maule Aftershock Deployment in Central Chile. The performance and potential of the method to detect, locate and characterize the energy release associated with possibly mixed seismic radiation from earthquakes and low-frequency tectonic tremors is further tested on continuous data from southwestern Japan.

  15. New York/New Jersey regional seismic network

    SciTech Connect

    Seeber, L.; Simpson, D.; Johnson, D.; Armbruster, J. . Lamont-Doherty Geological Observatory)

    1991-09-01

    Lamont-Doherty Geological Observatory (L-DGO) continued operating a 31-station seismic network covering parts of New York and New Jersey. The network is being transformed into sub-networks with stations radio telemetered to smart'' recording stations. The sub-network approach is capable of providing improved data at reduced cost. The major research effort during the period of this report was centered about the Saguenay earthquake sequence in Quebec. L-DGO collaborated with the Canadian Geologic Survey in monitoring aftershocks with temporary local stations. Analysis of data from the 1985 Ardsley earthquake in Westchester county continued with a Green's function deconvolution approach to resolve the dimensions of the rupture of the main shock (Mb=4.0) and of the largest aftershock (Mb=3.0). The results corroborate the 1/2-1 km diameter inferred for the rupture and suggest that the segmentation of the Dobbs Ferry fault and of similar in the Manhattan Prong may be controlling the size of historic earthquakes in the New York City region. Finally, a portable seismograph survey was carried out in Palco, Kansas, which showed clearly that seismicity at Palco was induced. 51 refs,, 8 figs., 2 tabs.

  16. Caltech/USGS Southern California Seismic Network: Recent Developments

    NASA Astrophysics Data System (ADS)

    Bhadha, R.; Chen, S.; Crummey, J.; Hauksson, E.; Solanki, K.; Thomas, V. I.; Watkins, M.; Yip, R.; Yu, E.; Given, D.; Peats, R.; Schwarz, S.

    2010-12-01

    The SCSN is the modern digital ground motion seismic network in Southern California and performs the following tasks: 1) Operates remote seismic stations and the central data processing systems in Pasadena; 2) Generates and reports real-time products including location, magnitude, ShakeMap, and others; 3) Responds to FEMA, CalEMA, media, and public inquiries about earthquakes; 4) Manages the production, archival, and distribution of waveforms, phase picks, and other data at the SCEDC; 5) Contributes to development and maintenance of the ANSS Quake Monitoring System (AQMS) software to add new features and improve robustness; 6) Supports the deployment of AQMS to other ANSS member regional seismic networks. The public regularly accesses the CISN, SCSN, and SCEDC web pages for up-to-date quake info and more than 230,000 users subscribe to the Electronic Notification System (ENS) which sends rapid notifications via email and cell phones. We distribute our products via Internet (EIDS), email, and paging, to USGS in Reston and Golden, FEMA, CalEMA, local governments, partner members, and other subscribers. We have developed CISN Display and provide ShakeCast for customers who require real-time earthquake information. The SCSN also exchanges waveform, phase pick, and amplitude data in real-time with several other partner networks, including Menlo Park, UCB, UNR, Anza network, the Tsunami Warning Centers, IRIS, and the NEIC. We operate a number of 24/7 on-call rotations to provide quick response to verify seismic events as well as addressing systems and telemetry issues. As part of our goals to improve quality, robustness, and coverage, some of our recent efforts include: 1) Converting the digital stations in the network to Q330 dataloggers; 2) Developing command and control capabilities such as automated mass re-centering; 3) Migration from serial to Ethernet communications; 4) Clustering of data acquisition servers for fail-over to improve data availability; 5) Use of

  17. Impact of sensor installation techniques on seismic network performance

    NASA Astrophysics Data System (ADS)

    Bainbridge, Geoffrey; Laporte, Michael; Baturan, Dario; Greig, Wesley

    2015-04-01

    The magnitude of completeness (Mc) of a seismic network is determined by a number of factors including station density, self-noise and passband of the sensor used, ambient noise environment and sensor installation method and depth. Sensor installation techniques related to depth are of particular importance due to their impact on overall monitoring network deployment costs. We present a case study which evaluates performance of Trillium Compact Posthole seismometers installed using different methods as well as depths, and evaluate its impact on seismic network operation in terms of the target area of interest average magnitude of completeness in various monitoring applications. We evaluate three sensor installation methods: direct burial in soil at 0.5 m depth, 5 m screwpile and 15 m cemented casing borehole at sites chosen to represent high, medium and low ambient noise environments. In all cases, noise performance improves with depth with noise suppression generally more prominent at higher frequencies but with significant variations from site to site. When extended to overall network performance, the observed noise suppression results in improved (decreased) target area average Mc. However, the extent of the improvement with depth varies significantly, and can be negligible. The increased cost associated with installation at depth uses funds that could be applied to the deployment of additional stations. Using network modelling tools, we compare the improvement in magnitude of completeness and location accuracy associated with increasing installation depth to those associated with increased number of stations. The appropriate strategy is applied on a case-by-case and driven by network-specific performance requirements, deployment constraints and site noise conditions.

  18. Caucasus Seismic Information Network: Data and Analysis Final Report

    SciTech Connect

    Randolph Martin; Mary Krasovec; Spring Romer; Timothy O'Connor; Emanuel G. Bombolakis; Youshun Sun; Nafi Toksoz

    2007-02-22

    The geology and tectonics of the Caucasus region (Armenia, Azerbaijan, and Georgia) are highly variable. Consequently, generating a structural model and characterizing seismic wave propagation in the region require data from local seismic networks. As of eight years ago, there was only one broadband digital station operating in the region – an IRIS station at Garni, Armenia – and few analog stations. The Caucasus Seismic Information Network (CauSIN) project is part of a nulti-national effort to build a knowledge base of seismicity and tectonics in the region. During this project, three major tasks were completed: 1) collection of seismic data, both in event catalogus and phase arrival time picks; 2) development of a 3-D P-wave velocity model of the region obtained through crustal tomography; 3) advances in geological and tectonic models of the region. The first two tasks are interrelated. A large suite of historical and recent seismic data were collected for the Caucasus. These data were mainly analog prior to 2000, and more recently, in Georgia and Azerbaijan, the data are digital. Based on the most reliable data from regional networks, a crustal model was developed using 3-D tomographic inversion. The results of the inversion are presented, and the supporting seismic data are reported. The third task was carried out on several fronts. Geologically, the goal of obtaining an integrated geological map of the Caucasus on a scale of 1:500,000 was initiated. The map for Georgia has been completed. This map serves as a guide for the final incorporation of the data from Armenia and Azerbaijan. Description of the geological units across borders has been worked out and formation boundaries across borders have been agreed upon. Currently, Armenia and Azerbaijan are working with scientists in Georgia to complete this task. The successful integration of the geologic data also required addressing and mapping active faults throughout the greater Caucasus. Each of the major

  19. Application of neural networks to seismic active control

    SciTech Connect

    Tang, Yu

    1995-07-01

    An exploratory study on seismic active control using an artificial neural network (ANN) is presented in which a singledegree-of-freedom (SDF) structural system is controlled by a trained neural network. A feed-forward neural network and the backpropagation training method are used in the study. In backpropagation training, the learning rate is determined by ensuring the decrease of the error function at each training cycle. The training patterns for the neural net are generated randomly. Then, the trained ANN is used to compute the control force according to the control algorithm. The control strategy proposed herein is to apply the control force at every time step to destroy the build-up of the system response. The ground motions considered in the simulations are the N21E and N69W components of the Lake Hughes No. 12 record that occurred in the San Fernando Valley in California on February 9, 1971. Significant reduction of the structural response by one order of magnitude is observed. Also, it is shown that the proposed control strategy has the ability to reduce the peak that occurs during the first few cycles of the time history. These promising results assert the potential of applying ANNs to active structural control under seismic loads.

  20. A new integrated approach to seismic network optimization

    NASA Astrophysics Data System (ADS)

    Tramelli, A.; De Natale, G.; Troise, C.; Orazi, M.

    2012-04-01

    A seismic network is usually deployed to monitor the seismicity, to locate earthquakes and compute source parameters. The network configuration is crucial due to the important implications on the quality of the information that can be obtained, therefore, it requires a detailed study in order to maximize the information-to-cost ratio. Fundamental, for the network optimization, is the clear definition of the goals which must be reached, the experimental constraints and the physical relationship between data and model. In order to maximize the performance of a particular design a quantitative measure of such performance must be defined. Once a quality function has been rigorously defined for each individual goal, an optimization criterion can be defined, which maximizes it. In particular, for the seismic location problem such criterion may be based on the minimization of the statistical location errors. A similar criterion of error minimization can be equivalently used for moment tensor determination, double-couple focal mechanisms estimation, scalar source parameters determination, etc. We present here suitable algorithms developed and tested for network optimization. As optimization parameter, we propose to use the ratio between the larger to the smaller eigenvalue of the information matrix. Such ratio is proportional to the ratio between solution and data errors, i.e. it represents the amplification factor which propagates data errors into the solution. The optimization problem tries to define, among a set of M possible sites, which are the N ones (with Nnetwork or to design

  1. The Need &Utility of Creating a Global Lunar Seismic Network

    NASA Astrophysics Data System (ADS)

    Neal, C. R.; Salvati, L.; Lognonné, P.; Banerdt, B.; Nakamura, Y.

    2006-12-01

    The Apollo Passive Seismic Network (PSN) showed the Moon was seismically active on a scale similar to intraplate seismicity on Earth, but the small area covered by the PSN has prevented definitive conclusions being made about the deep lunar interior. For example, increased velocities at depths >500 km have large errors associated with them so mineralogical interpretations are poorly constrained; an increased proportion of Mg-rich olivine or the presence of garnet could explain the current data. Lunar Prospector data estimated a metallic lunar core with a radius of 340 km. However, existing geophysical data are consistent with either a metal or ilmenite core. Four types of lunar seismic events were documented: 1) Thermal moonquakes (smallest magnitude event) - associated with stresses induced by surface diurnal temperature changes. 2) Deep moonquakes (magnitude 2 or less) - >7,000 having been recognized. These events occur 700-1,200 km within the Moon and are associated with Earth's tidal pull. 3) Meteoroid impacts exhibit characteristic seismic waveforms; >1,700 events representing masses of 0.1-1,000 kg were recorded. 4) Shallow moonquakes (high frequency teleseismic events) have hypocenters of 50-200 km, but exact depths and locations are unknown because all recorded events were out¬side the Apollo PSN. Shallow moonquakes are the strongest type of event, with 7 of the 28 events being magnitude 5 or greater. The causes of such quakes are not known. Shallow moonquakes are a potential hazard to a long-term lunar habitat. Applying earthquake models directly to the Moon, estimates of epicentral ground acceleration for a mb 5.7 moonquake are 0.20-0.25 m s^{- 2} (100 km focal depth). Ground motion (amplitude) estimates are ~3 cm at 2 Hz to ~0.75 cm at 8 Hz, ~1 km from the epicenter. However, moonquakes are significantly different from earthquakes: 1) shallow moonquakes contain more energy at high frequencies than earthquakes of comparable total energy; 2) coherent

  2. Modernization of the Caltech/USGS Southern California Seismic Network

    NASA Astrophysics Data System (ADS)

    Bhadha, R.; Devora, A.; Hauksson, E.; Johnson, D.; Thomas, V.; Watkins, M.; Yip, R.; Yu, E.; Given, D.; Cone, G.; Koesterer, C.

    2009-12-01

    The USGS/ANSS/ARRA program is providing Government Furnished Equipment (GFE), and two year funding for upgrading the Caltech/USGS Southern California Seismic Network (SCSN). The SCSN is the modern digital ground motion seismic network in southern California that monitors seismicity and provides real-time earthquake information products such as rapid notifications, moment tensors, and ShakeMap. The SCSN has evolved through the years and now consists of several well-integrated components such as Short-Period analog, TERRAscope, digital stations, and real-time strong motion stations, or about 300 stations. In addition, the SCSN records data from about 100 stations provided by partner networks. To strengthen the ability of SCSN to meet the ANSS performance standards, we will install GFE and carry out the following upgrades and improvements of the various components of the SCSN: 1) Upgrade of dataloggers at seven TERRAscope stations; 2) Upgrade of dataloggers at 131 digital stations and upgrade broadband sensors at 25 stations; 3) Upgrade of SCSN metadata capabilities; 4) Upgrade of telemetry capabilities for both seismic and GPS data; and 5) Upgrade balers at stations with existing Q330 dataloggers. These upgrades will enable the SCSN to meet the ANSS Performance Standards more consistently than before. The new equipment will improve station uptimes and reduce maintenance costs. The new equipment will also provide improved waveform data quality and consequently superior data products. The data gaps due to various outages will be minimized, and ‘late’ data will be readily available through retrieval from on-site storage. Compared to the outdated equipment, the new equipment will speed up data delivery by about 10 sec, which is fast enough for earthquake early warning applications. The new equipment also has about a factor of ten lower consumption of power. We will also upgrade the SCSN data acquisition and data center facilities, which will improve the SCSN

  3. The Self-Organising Seismic Early Warning Information Network

    NASA Astrophysics Data System (ADS)

    Kühnlenz, F.; Eveslage, I.; Fischer, J.; Fleming, K. M.; Lichtblau, B.; Milkereit, C.; Picozzi, M.

    2009-12-01

    The Self-Organising Seismic Early Warning Information Network (SOSEWIN) represents a new approach for Earthquake Early Warning Systems (EEWS), consisting in taking advantage of novel wireless communications technologies without the need of a planned, centralised infrastructure. It also sets out to overcome problems of insufficient node density, which typically affects present existing early warning systems, by having the SOSEWIN seismological sensing units being comprised of low-cost components (generally bought "off-the-shelf"), with each unit initially costing 100's of Euros, in contrast to 1,000's to 10,000's for standard seismological stations. The reduced sensitivity of the new sensing units arising from the use of lower-cost components will be compensated by the network's density, which in the future is expected to number 100's to 1000's over areas served currently by the order of 10's of standard stations. The robustness, independence of infrastructure, spontaneous extensibility due to a self-healing/self-organizing character in the case of removing/failing or adding sensors makes SOSEWIN potentially useful for various use cases, e.g. monitoring of building structures or seismic microzonation. Nevertheless its main purpose is the earthquake early warning, for which reason the ground motion is continuously monitored by conventional accelerometers (3-component) and processed within a station. Based on this, the network itself decides whether an event is detected through cooperating stations. SEEDLink is used to store and provide access to the sensor data. Experiences and selected experiment results with the SOSEWIN-prototype installation in the Ataköy district of Istanbul (Turkey) are presented. SOSEWIN considers also the needs of earthquake task forces, which want to set-up a temporary seismic network rapidly and with light-weighted stations to record after-shocks. The wireless and self-organising character of this sensor network is of great value to do this

  4. The Self-Organising Seismic Early Warning Information Network: Scenarios

    NASA Astrophysics Data System (ADS)

    Kühnlenz, F.; Fischer, J.; Eveslage, I.

    2009-04-01

    SAFER and EDIM working groups, the Department of Computer Science, Humboldt-Universität zu Berlin, Berlin, Germany, and Section 2.1 Earthquake Risk and Early Warning, GFZ German Research Centre for Geosciences, Germany Contact: Frank Kühnlenz, kuehnlenz@informatik.hu-berlin.de The Self-Organising Seismic Early Warning Information Network (SOSEWIN) represents a new approach for Earthquake Early Warning Systems (EEWS), consisting in taking advantage of novel wireless communications technologies without the need of a planned, centralised infrastructure. It also sets out to overcome problems of insufficient node density, which typically affects present existing early warning systems, by having the SOSEWIN seismological sensing units being comprised of low-cost components (generally bought "off-the-shelf"), with each unit initially costing 100's of Euros, in contrast to 1,000's to 10,000's for standard seismological stations. The reduced sensitivity of the new sensing units arising from the use of lower-cost components will be compensated by the network's density, which in the future is expected to number 100's to 1000's over areas served currently by the order of 10's of standard stations. The robustness, independence of infrastructure, spontaneous extensibility due to a self-healing/self-organizing character in the case of removing/failing or adding sensors makes SOSEWIN potentially useful for various use cases, e.g. monitoring of building structures or seismic microzonation. Nevertheless its main purpose is the earthquake early warning, for which reason the ground motion is continuously monitored by conventional accelerometers (3-component). It uses SEEDLink to store and provide access to the sensor data. SOSEWIN considers also the needs of earthquake task forces, which want to set-up a temporary seismic network rapidly and with light-weighted stations to record after-shocks. The wireless and self-organising character of this sensor network should be of great value

  5. Romanian Complex Data Center for Dense Seismic network

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

    Since 2002 the National Institute for Earth Physics (NIEP) developed its own real-time digital seismic network: consisting of 96 seismic stations of which 35 are broadband sensors and 24 stations equipped with short period sensors and two arrays earthquakes that transmit data in real time 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 Black Sea tsunamis. Seismic stations are equipped with Quanterra Q330 and K2 digitizers, broadband seismometers (STS2, CMG40T, CMG 3ESP, CMG3T) and acceleration sensors Episensor Kinemetrics (+ / - 2G). SeedLink who is a part of Seiscomp2.5 and Antelope are software packages used for acquisition in real time (RT) and for data exchange. Communication of digital seismic stations to the National Data Center in Bucharest and Seismic Observatory Eforie Nord is assured by 5 providers (GPRS, VPN, satellite radio and Internet communication). For acquisition and data processing at the two centers of reception and processing is used AntelopeTM 4.11 running on 2 workstations: one for real-time and other for offline processing and also a Seiscomp 3 server that works as back-up for Antelope 4.11 Both acquisition and analysis of seismic data systems produced information about local and global parameters of earthquakes, in addition Antelope is used for manual processing (association events, the calculation of magnitude, creating a database, sending seismic bulletins, calculation of PGA and PGV , etc.), generating ShakeMap products and interacts with global data centers. In order to make all this information easily available across the Web and also lay the grounds for a more modular and flexible development environment the National Data Center developed tools to enable centralizing of data from software such as Antelope which is using a dedicated database system ( Datascope, a database system based on text files ) to a more general-purpose database, My

  6. Use of Romanian Seismic Network to monitor nuclear explosions

    NASA Astrophysics Data System (ADS)

    Ghica, Daniela; Neagoe, Cristian; Grecu, Bogdan; Popa, Mihaela

    2014-05-01

    During the last decade, three underground nuclear tests were conducted by the Democratic People's Republic of Korea (DPRK): on October 9, 2006, May 25, 2009, and February 12, 2013. The magnitude of the events, estimated by International Data Centre (IDC) as 4.1, 4.5 and 4.9, indicates that the latest was more powerful than its predecessors. We analyze seismic signals generated by the DPRK tests and recorded with Romanian Seismic Network (RSN). The location estimates performed at Romania National Data Centre (NDC) using RSN data, were compared with those obtained at IDC. As a consequence of the global superior coverage with seismic stations included in the International Monitoring System, IDC locations are better constrained. The signals generated by 2006 DPRK nuclear test were observed on 8 RSN stations, the 2009 test on 33, and the 2013 test on 47. This continuous increase is due to the rise in the number of stations installed during last five years, as well as to the larger magnitude of the 2013 test. The recent development of RSN has enabled NDC to locate the events with more accuracy, based on the higher-quality parameters estimated from data processing. For all three events, a high signal coherency is observed for the data recorded by the Romanian seismic array, BURAR, reconfirming the superiority of the arrays to single stations for detecting and characterizing signals from nuclear explosions. Array processing techniques are applied for signal detection and to estimate the slowness vector (back-azimuth and apparent velocity). The comparison of vertical displacement seismograms recorded at RSN stations shows a remarkably similarity of the signals generated by the three events analyzed. The records are nearly identical, except that the amplitude is directly proportional to the event magnitude. Spectrograms of the recorded RSN data were examined, showing that the nuclear explosions produce seismic signals with a high energy in the 0.5 to 2.0 Hz frequency range

  7. The European Virtual Broadband Seismic Network (VEBSN) and ORFEUS

    NASA Astrophysics Data System (ADS)

    van Eck, Torild; Sleeman, Reinoud; van den, Gert-Jan Hazel; Networks, Contributing

    2010-05-01

    Since 2002 ORFEUS has been coordinating the VEBSN concept, in which (near) real-time data is exchanged between Seismological observatory networks and the Orfeus Data Center (ODC). Seismological observatories in and around Europe have usually as primary objective the monitoring and analysis of current local and regional seismicity and seismic hazard. The data gathered by the observatories is, however, also valuable for fundamental research within global and European scale seismology; and therefore a primary data source for Academic seismological research. Within the VEBSN concept, the ODC provides and improves Quality control procedures for the observatories and the observatories provide real-time data for long-term secure waveform data archives at the ODC accessible for seismological research. In this concept the data remains ownership of the contributing network, while the ODC provides a secure back-up archive of waveform data. By facilitating a few data exchange mechanism with emphasis on SeedLink, the VEBSN strategy also enables observatories to exchange data between each other, thus enhancing the capabilities of the local or regional network and improving its performance for their monitoring and hazard objectives More recently, the ODC has been enlarged into the European Distributed waveform Data Archive (EIDA) in which currently GFZ/GEOFON, INGV and RESIF participate in an effort to extend the accessible waveform archive beyond only the VEBSN data. Currently the VEBSN consists of more then 450 3-component stations, each channel well defined with a full up-to-date SEED volume, providing all relevant metadata for a full reconstruction of the true ground motion. This encompases only about 45% of the operational BB stations in the European-Mediterranean area and our goal is to enlarge this.

  8. Strong Ground Motion Database System for the Mexican Seismic Network

    NASA Astrophysics Data System (ADS)

    Perez-Yanez, C.; Ramirez-Guzman, L.; Ruiz, A. L.; Delgado, R.; Macías, M. A.; Sandoval, H.; Alcántara, L.; Quiroz, A.

    2014-12-01

    A web-based system for strong Mexican ground motion records dissemination and archival is presented. More than 50 years of continuous strong ground motion instrumentation and monitoring in Mexico have provided a fundamental resource -several thousands of accelerograms- for better understanding earthquakes and their effects in the region. Lead by the Institute of Engineering (IE) of the National Autonomous University of Mexico (UNAM), the engineering strong ground motion monitoring program at IE relies on a continuously growing network, that at present includes more than 100 free-field stations and provides coverage to the seismic zones in the country. Among the stations, approximately 25% send the observed acceleration to a processing center in Mexico City in real-time, and the rest require manual access, remote or in situ, for later processing and cataloguing. As part of a collaboration agreement between UNAM and the National Center for Disaster Prevention, regarding the construction and operation of a unified seismic network, a web system was developed to allow access to UNAM's engineering strong motion archive and host data from other institutions. The system allows data searches under a relational database schema, following a general structure relying on four databases containing the: 1) free-field stations, 2) epicentral location associated with the strong motion records available, 3) strong motion catalogue, and 4) acceleration files -the core of the system. In order to locate and easily access one or several records of the data bank, the web system presents a variety of parameters that can be involved in a query (seismic event, region boundary, station name or ID, radial distance to source or peak acceleration). This homogeneous platform has been designed to facilitate dissemination and processing of the information worldwide. Each file, in a standard format, contains information regarding the recording instrument, the station, the corresponding earthquake

  9. The Irpinia Seismic Network (ISNet): hardware and data management

    NASA Astrophysics Data System (ADS)

    Iannaccone, G.

    2009-04-01

    The Irpinia Seismic Network, operating in southern Italy, is primarily aimed at providing an alert for moderate to large earthquakes in selected target sites in the Campania Region, and it also provides data for rapid computation of regional ground-shaking maps. ISNet is deployed over the active seismic faults system of Irpinia, southern Italy. It features 28 seismic stations and 5 data processing sites (local control centers - LCC). All stations are equipped with a strong-motion accelerometer and a three component velocimeter, with a one second natural period, for a high dynamic recording range. Five stations host broadband sensors, for recording regional and teleseismic events. The recorded seismic data are sent from each station to the nearby LCC, through a Wi-Fi directional antenna, in SeedLink format. Each LCC runs: the SeisComP software, to relay the data to outside SeedLink clients; the Earthworm system, for real-time processing (e.g. to produce a bulletin of automatically detected events); the Winston software, for data storage and visualization. To monitor and maintain all of the described ISNet instrumentation, and to access, analyze and edit the seismic data produced, we developed a software application, SeismNet Manager, that implements a web-based user interface to a database of all the ISNet information and data. For early warning applications, a high bandwidth radio links backbone is being deployed, interconnecting the LCCs and the Network Control Center in Naples. We developed a software application that processes the live streams of 3-component acceleration from the stations and, while an energetic event is occurring, promptly performs picking, event detection, event location and magnitude estimation. The earthquake location uses an evolutionary, real-time technique based on an equal differential time (EDT) formulation, and a probabilistic approach for describing the hypocenter. This algorithm, at each time step, relies on both the information from

  10. 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.

  11. The California Integrated Seismic Network:status and perspectives

    NASA Astrophysics Data System (ADS)

    CISN,

    2001-12-01

    The California Integrated Seismic Network (CISN) is a consortium of federal, state and academic institutions engaged in earthquake monitoring in California. The CISN represents California as a designated region of the Advanced National Seismic System (ANSS). The CISN is governed by a Steering Committee representing institutions actively involved in earthquake monitoring in California (currently USGS, CDMG, UCB and Caltech) and the California OES. Current members of the CISN Steering Committee are Barbara Romanowicz (chair) and Lind Gee (both at UCB), David Oppenheimer and Mary-Lou Zoback (both at USGS/Menlo Park), Egill Hauksson and Robert Clayton (both at Caltech), Jim Davis and Tony Shakal (both at CDMG), Lucy Jones (vice-chair) and David Wald (both at USGS/Pasadena), Rich Eisner (OES) and Chris Poland (Degenkolb Engineers; head of the CISN Advisory Committee). A major goal of the CISN is to ensure a more uniform system for earthquake monitoring, through the improvement of seismic infrastructure in northern California and continued maintenance of the TriNet system in southern California. Another major goal is to integrate the earthquake monitoring and reporting efforts in California, utilizing compatible softrware and creating a single catalog. In particular, we will work to improve the robustness of statewide rapid notification and work with the California OES and other emergency responders to maximize the use and benefit of this real time seismic information. In the coming year, with new support from the State of California through the Office of Emergency Services, and from the ANSS program of the USGS, more than 50 new strong-motion stations will be installed, with a focus in the San Francisco Bay Area, in order to improve coverage for ShakeMap and 2 new broadband stations will be deployed in northern California to enhance earthquake reporting. CISN is also contributing to structural monitoring. The CISN is also focusing on data distribution and plans to

  12. A comprehensive approach for evaluating network performance in surface and borehole seismic monitoring

    NASA Astrophysics Data System (ADS)

    Stabile, T. A.; Iannaccone, G.; Zollo, A.; Lomax, A.; Ferulano, M. F.; Vetri, M. L. V.; Barzaghi, L. P.

    2013-02-01

    The accurate determination of locations and magnitudes of seismic events in a monitored region is important for many scientific, industrial and military studies and applications; for these purposes a wide variety of seismic networks are deployed throughout the world. It is crucial to know the performance of these networks not only in detecting and locating seismic events of different sizes throughout a specified source region, but also by evaluating their location errors as a function of the magnitude and source location. In this framework, we have developed a method for evaluating network performance in surface and borehole seismic monitoring. For a specified network geometry, station characteristics and a target monitoring volume, the method determines the lowest magnitude of events that the seismic network is able to detect (Mwdetect), and locate (Mwloc) and estimates the expected location and origin time errors for a specified magnitude. Many of the features related to the seismic signal recorded at a single station are considered in this methodology, including characteristics of the seismic source, the instrument response, the ambient noise level, wave propagation in a layered, anelastic medium and uncertainties on waveform measures and the velocity model. We applied this method to two different network typologies: a local earthquake monitoring network, Irpinia Seismic Network (ISNet), installed along the Campania-Lucania Apennine chain in Southern Italy, and a hypothetic borehole network for monitoring microfractures induced during the hydrocarbon extraction process in an oil field. The method we present may be used to aid in enhancing existing networks and/or understanding their capabilities, such as for the ISNet case study, or to optimally design the network geometry in specific target regions, as for the borehole network example.

  13. Kansas-Nebraska seismicity studies using the Kansas-Nebraska microearthquake network: Final report

    SciTech Connect

    Steeples, D.W.; Hildebrand, G.M.; Bennett, B.C.; Miller, R.D.; Chung, Y.; Knapp, R.W.

    1988-03-01

    The Kansas Geological Survey (KGS) operates a 15 station seismograph network with stations located in northeast Kansas and southeast Nebraska. The network is supported in part by funding from the United States Nuclear Regulatory Commission (NRC). This report discusses operation of the network and summarizes the results of research that allows a better understanding of the seismicity of the region and the link between the seismicity and the tectonic setting of the region. 29 refs., 12 figs., 4 tabs.

  14. Scientific Rationale and Requirements for a Global Seismic Network on Mars

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.; Anderson, Don L.; Banerdt, W. Bruce; Butler, Rhett G.; Davis, Paul M.; Duennebier, Frederick K.; Nakamura, Yosio; Okal, Emile A.; Phillips, Roger J.

    1991-01-01

    Following a brief overview of the mission concepts for a Mars Global Network Mission as of the time of the workshop, we present the principal scientific objectives to be achieved by a Mars seismic network. We review the lessons for extraterrestrial seismology gained from experience to date on the Moon and on Mars. An important unknown on Mars is the expected rate of seismicity, but theoretical expectations and extrapolation from lunar experience both support the view that seismicity rates, wave propagation characteristics, and signal-to-noise ratios are favorable to the collection of a scientifically rich dataset during the multiyear operation of a global seismic experiment. We discuss how particular types of seismic waves will provide the most useful information to address each of the scientific objectives, and this discussion provides the basis for a strategy for station siting. Finally, we define the necessary technical requirements for the seismic stations.

  15. False alarms and mine seismicity: An example from the Gentry Mountain mining region, Utah. Los Alamos Source Region Project

    SciTech Connect

    Taylor, S.R.

    1992-09-23

    Mining regions are a cause of concern for monitoring of nuclear test ban treaties because they present the opportunity for clandestine nuclear tests (i.e. decoupled explosions). Mining operations are often characterized by high seismicity rates and can provide the cover for excavating voids for decoupling. Chemical explosions (seemingly as part of normal mining activities) can be used to complicate the signals from a simultaneous decoupled nuclear explosion. Thus, most concern about mines has dealt with the issue of missed violations to a test ban treaty. In this study, we raise the diplomatic concern of false alarms associated with mining activities. Numerous reports and papers have been published about anomalous seismicity associated with mining activities. As part of a large discrimination study in the western US (Taylor et al., 1989), we had one earthquake that was consistently classified as an explosion. The magnitude 3.5 disturbance occurred on May 14, 1981 and was conspicuous in its lack of Love waves, relative lack of high- frequency energy, low Lg/Pg ratio, and high m{sub b} {minus} M{sub s}. A moment-tensor solution by Patton and Zandt (1991) indicated the event had a large implosional component. The event occurred in the Gentry Mountain coal mining region in the eastern Wasatch Plateau, Utah. Using a simple source representation, we modeled the event as a tabular excavation collapse that occurred as a result of normal mining activities. This study raises the importance of having a good catalogue of seismic data and information about mining activities from potential proliferant nations.

  16. Automated Moment Tensor Solution for the Southern California Seismic Network

    NASA Astrophysics Data System (ADS)

    Clinton, J. F.; Hauksson, E.; Solanki, K.

    2004-12-01

    Automatically generated moment tensor solutions have recently been added to the suite of real-time products produced by the Southern California Seismic Network (SCSN/CISN). The moment magnitude, Mw, and the moment tensor are available within minutes for all regional earthquakes that trigger the network with Ml>4.0, and in special cases for events between Ml 3.5-4.0. The method uses the 1-D Time-Domain INVerse Code (TDMT_INVC) software package developed by Doug Dreger, which is routinely used in real-time by the UC Berkeley Seismological Laboratory. Green's Functions are determined for various velocity profiles in Southern California, which are used in the inversion of observed three component broadband waveforms (10s-100s) for a number of stations. The duty seismologists will review the automatically generated solution before distribution. A web-interface has been developed to evaluate the quality of the automatic solution, and determine whether it meets the minimum requirements for an immediate distribution. Simple modifications to the stations selected for the inversion are possible, and the inversion can be re-run to optimise the solution. The Mw determined with this method will be the official SCSN/CISN Mw solution for the event. Comparisons of the moment tensors determined using this 1-D model are made with 3-D models generated for larger earthquakes in the Southern California to facilitate calibration of the automated algorithm.

  17. Local magnitude calibration of the Hellenic Unified Seismic Network

    NASA Astrophysics Data System (ADS)

    Scordilis, E. M.; Kementzetzidou, D.; Papazachos, B. C.

    2016-01-01

    A new relation is proposed for accurate determination of local magnitudes in Greece. This relation is based on a large number of synthetic Wood-Anderson (SWA) seismograms corresponding to 782 regional shallow earthquakes which occurred during the period 2007-2013 and recorded by 98 digital broad-band stations. These stations are installed and operated by the following: (a) the National Observatory of Athens (HL), (b) the Department of Geophysics of the Aristotle University of Thessaloniki (HT), (c) the Seismological Laboratory of the University of Athens (HA), and (d) the Seismological Laboratory of the Patras University (HP). The seismological networks of the above institutions constitute the recently (2004) established Hellenic Unified Seismic Network (HUSN). These records are used to calculate a refined geometrical spreading factor and an anelastic attenuation coefficient, representative for Greece and surrounding areas, proper for accurate calculation of local magnitudes in this region. Individual station corrections depending on the crustal structure variations in their vicinity and possible inconsistencies in instruments responses are also considered in order to further ameliorate magnitude estimation accuracy. Comparison of such calculated local magnitudes with corresponding original moment magnitudes, based on an independent dataset, revealed that these magnitude scales are equivalent for a wide range of values.

  18. A novel progressive signal association algorithm for detecting teleseismic/network-outside events using regional seismic networks

    NASA Astrophysics Data System (ADS)

    Jin, Ping; Pan, Changzhou; Zhang, Chengliu; Shen, Xufeng; Wang, Hongchun; Lu, Na

    2015-06-01

    Regional seismic networks may and in some cases need to be used to monitor teleseismic or network-outside events. For detecting and localizing teleseismic events automatically and reliably in this case, in this paper we present a novel progressive association algorithm for teleseismic signals recorded by a regional seismic network. The algorithm takes triangle station arrays as the starting point to search for P waves of teleseismic events progressively by that, as detections from different stations actually are from the same teleseismic event, their arrival times should be linearly related to the average slowness vector with which the signal propagates across the network, and the slowness of direct teleseismic P wave basically is different from other major seismic phases. We have tested this algorithm using data recorded by Xinjiang Seismic Network of China (XJSN) for 16 d. The results show that the algorithm can effectively and reliably detect and localize earthquakes outside of the network. For the period of the test data, as all mb 4.0+ events with Δc < 30° and all mb 4.5+ events with Δc < 60° referring to the International Data Center-Reviewed Event Bulletin (IDC REB) were detected, where Δc is the epicentral distance relative to the network's geographical centre, the rate of false events only accounted for 2.4 per cent, suggesting that the new association algorithm has good application prospect for situations when regional seismic networks need to be used to monitor teleseismic events.

  19. How a Country-Wide Seismological Network Can Improve Understanding of Seismicity and Seismic Hazard -- The Example of Bhutan

    NASA Astrophysics Data System (ADS)

    Hetényi, G.; Diehl, T.; Singer, J.; Kissling, E. H.; Clinton, J. F.; Wiemer, S.

    2015-12-01

    The Eastern Himalayas are home to a seemingly complex seismo-tectonic evolution. The rate of instrumental seismicity is lower than the average along the orogen, there is no record of large historical events, but both paleoseismology and GPS studies point to potentially large (M>8) earthquakes. Due to the lack of a permanent seismic monitoring system in the area, our current level of understanding is inappropriate to create a reliable quantitative seismic hazard model for the region. Existing maps are based on questionable hypotheses and show major inconsistencies when compared to each other. Here we present results on national and regional scales from a 38-station broadband seismological network we operated for almost 2 years in the Kingdom of Bhutan. A thorough, state-of-the-art analysis of local and regional earthquakes builds a comprehensive catalogue that reveals significantly (2-to-3 orders of magnitude) more events than detected from global networks. The seismotectonic analysis reveals new patterns of seismic activity as well as striking differences over relatively short distances within the Himalayas, only partly explained by surface observations such as geology. We compare a priori and a posteriori (BMC) magnitude of completeness maps and show that our network was able to detect all felt events during its operation. Some of these events could be felt at surprisingly large distances. Based on our experiment and experience, we draft the pillars on which a permanent seismological observatory for Bhutan could be constructed. Such a continuous monitoring system of seismic activity could then lead to a reliable quantitative seismic hazard model for Bhutan and surrounding regions, and serve as a base to improve building codes and general preparedness.

  20. The Self-Organising Seismic Early Warning Information Network

    NASA Astrophysics Data System (ADS)

    Picozzi, M.

    2009-04-01

    The Self-Organizing Seismic Early Warning Information Network (SOSEWIN) represents a new approach for Earthquake Early Warning Systems (EEWS), consisting in taking advantage of novel wireless communications technologies. It also sets out to overcome problems of insufficient node density, which typically affects present existing early warning systems, by having the SOSEWIN seismological sensing units being comprised of low-cost components (generally bought "off-the-shelf"), with each unit initially costing 100's of Euros, in contrast to 1,000's to 10,000's for standard seismological stations. The reduced sensitivity of the new sensing units arising from the use of lower-cost components will be compensated by the network's density, which in the future is expected to number 100's to 1000's over areas served currently by the order of 10's of standard stations. The robustness, independence of infrastructure, spontaneous extensibility and a self-healing/self-organizing character in the event of failing sensors during an earthquake makes SOSEWIN particularly useful for urban areas. Moreover, in the post-event time frame, negligible assumptions or interpolations would be necessary for assessing the strong ground shaking and earthquake intensities. In SOSEWIN, the ground motion is continuously monitored by conventional accelerometers (3-component) and geophones and analyzed using robust signal analysis methods by each sensing node of the network. The incoming signals are pre-processed by bandpass filtering and the detection processing is performed using an automatic STA/LTA trigger algorithm. Signal attributes are iteratively estimated from the P-wave part of the recordings (e.g. PGA, PGV, PGD, Arias Intensity and Cumulative Absolute Velocity) to determine if the earthquake is of sufficient magnitude to be of concern to issue a system alarm. Differently from most existing EEWS where the alarming system relies on estimates provided by only a few seismic stations, the SOSEWIN

  1. The Self-Organising Seismic Early Warning Information Network

    NASA Astrophysics Data System (ADS)

    Zschau, J.; Picozzi, M.; Milkereit, C.; Fleming, K.; Fischer, J.; Kuehnlenz, F.; Lichtblau, B.; Erdik, M.

    2008-12-01

    The Self-Organizing Seismic Early Warning Information Network (SOSEWIN) represents a new approach for Earthquake Early Warning Systems (EEWS), consisting in taking advantage of novel wireless communications technologies. It also sets out to overcome problems of insufficient node density, which typically affects present existing early warning systems, by having the SOSEWIN seismological sensing units being comprised of low-cost components (generally bought "off-the-shelf"), with each unit initially costing 100's of Euros, in contrast to 1,000's to 10,000's for standard seismological stations. The reduced sensitivity of the new sensing units arising from the use of lower-cost components will be compensated by the network's density, which in the future is expected to number 100's to 1000's over areas served currently by the order of 10's of standard stations. The robustness, independence of infrastructure, spontaneous extensibility and a self-healing/self-organizing character in the event of failing sensors during an earthquake makes SOSEWIN particularly useful for urban areas. Moreover, in the post-event time frame, negligible assumptions or interpolations would be necessary for assessing the strong ground shaking and earthquake intensities. In SOSEWIN, the ground motion is continuously monitored by conventional accelerometers (3-component) and geophones and analyzed using robust signal analysis methods by each sensing node of the network. The incoming signals are pre-processed by bandpass filtering and the detection processing is performed using an automatic STA/LTA trigger algorithm. Signal attributes are iteratively estimated from the P-wave part of the recordings (e.g. PGAP, PGVP, PGDP, Arias Intensity and Cumulative Absolute Velocity) to determine if the earthquake is of sufficient magnitude to be of concern to issue a system alarm. Differently from most existing EEWS where the alarming system relies on estimates provided by only a few seismic stations, the

  2. Operating a global seismic network - perspectives from the USGS GSN

    NASA Astrophysics Data System (ADS)

    Gee, L. S.; Derr, J. S.; Hutt, C. R.; Bolton, H.; Ford, D.; Gyure, G. S.; Storm, T.; Leith, W.

    2007-05-01

    The Global Seismographic Network (GSN) is a permanent digital network of state-of-the-art seismological and geophysical sensors connected by a global telecommunications network, serving as a multi-use scientific facility used for seismic monitoring for response applications, basic and applied research in solid earthquake geophysics, and earth science education. A joint program of the U.S. Geological Survey (USGS), the National Science Foundation, and Incorporated Research Institutions in Seismology (IRIS), the GSN provides near- uniform, worldwide monitoring of the Earth through 144 modern, globally distributed seismic stations. The USGS currently operates 90 GSN or GSN-affiliate stations. As a US government program, the USGS GSN is evaluated on several performance measures including data availability, data latency, and cost effectiveness. The USGS-component of the GSN, like the GSN as a whole, is in transition from a period of rapid growth to steady- state operations. The program faces challenges of aging equipment and increased operating costs at the same time that national and international earthquake and tsunami monitoring agencies place an increased reliance on GSN data. Data acquisition of the USGS GSN is based on the Quanterra Q680 datalogger, a workhorse system that is approaching twenty years in the field, often in harsh environments. An IRIS instrumentation committee recently selected the Quanterra Q330 HR as the "next generation" GSN data acquisition system, and the USGS will begin deploying the new equipment in the middle of 2007. These new systems will address many of the issues associated with the ageing Q680 while providing a platform for interoperability across the GSN.. In order to address the challenge of increasing operational costs, the USGS employs several tools. First, the USGS benefits from the contributions of local host institutions. The station operators are the first line of defense when a station experiences problems, changing boards

  3. Seismic Noise Analysis and Reduction through Utilization of Collocated Seismic and Atmospheric Sensors at the GRO Chile Seismic Network

    NASA Astrophysics Data System (ADS)

    Farrell, M. E.; Russo, R. M.

    2013-12-01

    The installation of Earthscope Transportable Array-style geophysical observatories in Chile expands open data seismic recording capabilities in the southern hemisphere by nearly 30%, and has nearly tripled the number of seismic stations providing freely-available data in southern South America. Through the use of collocated seismic and atmospheric sensors at these stations we are able to analyze how local atmospheric conditions generate seismic noise, which can degrade data in seismic frequency bands at stations in the ';roaring forties' (S latitudes). Seismic vaults that are climate-controlled and insulated from the local environment are now employed throughout the world in an attempt to isolate seismometers from as many noise sources as possible. However, this is an expensive solution that is neither practical nor possible for all seismic deployments; and also, the increasing number and scope of temporary seismic deployments has resulted in the collection and archiving of terabytes of seismic data that is affected to some degree by natural seismic noise sources such as wind and atmospheric pressure changes. Changing air pressure can result in a depression and subsequent rebound of Earth's surface - which generates low frequency noise in seismic frequency bands - and even moderate winds can apply enough force to ground-coupled structures or to the surface above the seismometers themselves, resulting in significant noise. The 10 stations of the permanent Geophysical Reporting Observatories (GRO Chile), jointly installed during 2011-12 by IRIS and the Chilean Servicio Sismológico, include instrumentation in addition to the standard three seismic components. These stations, spaced approximately 300 km apart along the length of the country, continuously record a variety of atmospheric data including infrasound, air pressure, wind speed, and wind direction. The collocated seismic and atmospheric sensors at each station allow us to analyze both datasets together, to

  4. 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.

  5. First-break refraction event picking and seismic data trace editing using neural networks

    SciTech Connect

    McCormack, M.D.; Zaucha, D.E.; Dushek, D.W. )

    1993-01-01

    Interactive seismic processing systems for editing noisy seismic traces and picking the first-break refraction events have been developed using a neural network learning algorithm. The authors employ a back propagation neural network (BNN) paradigm modified to improve the convergence rate of the BNN. The BNN is interactively trained'' to edit seismic data or pick first breaks by a human processor who judiciously selects and presents to the network examples of trace edits or refraction picks. The network then iteratively adjusts a set of internal weights until it can accurately duplicate the examples provided by the user. After the training session is completed, the BNN system an then process new data sets in a manner that mimics the human processor. Synthetic modeling studies indicated that the BNN uses many of the same subjective criteria that humans employ in editing and picking seismic data sets. Automated trace editing and first-break picking based on the modified BNN paradigm achieve 90 to 98 percent agreement with manual methods for seismic data of moderate to good quality. Productivity increases over manual editing, and picking techniques range from 60 percent for two-dimensional (2-D) data sets and up to 800 percent for three-dimensional (3-D) data sets. Neural network-based seismic processing can provide consistent and high quality results with substantial improvements in processing efficiency.

  6. Ocean bottom seismic and tsunami network along the Japan Trench

    NASA Astrophysics Data System (ADS)

    Uehira, K.; Kanazawa, T.; Noguchi, S.; Aoi, S.; Kunugi, T.; Matsumoto, T.; Okada, Y.; Sekiguchi, S.; Shiomi, K.; Shinohara, M.; Yamada, T.

    2012-12-01

    Huge tsunami, which was generated by the 2011 off the Pacific Coast of Tohoku Earthquake of M9 subduction zone earthquake, attacked the coastal areas in the north-eastern Japan and gave severe casualties (about 20,000 people) and property damages in the areas. The present tsunami warning system, based on land seismic observation data, did not work effectively in the case of the M9 earthquake. For example, real tsunami height was higher than that of forecast by this system. It is strongly acknowledged that marine observation data is necessary to make tsunami height estimation more accurately. Therefore, new ocean bottom observation project has started in 2011 that advances the countermeasures against earthquake and tsunami disaster related to subduction zone earthquake and outer rise earthquake around Japan Trench and Kuril Trench. A large scale ocean bottom cabled observation network is scheduled to be deployed around Japan Trench and Kuril Trench by 2015. The network is consisted of 154 ocean bottom observation stations. Ocean bottom fiber optic cables, about 5100 km in total length, connect the stations to land. Observation stations with tsunami meters and seismometers will be placed on the seafloor off Hokkaido, off Tohoku and off Kanto, in a spacing of about 30 km almost in the direction of East-West (perpendicular to the trench axis) and in a spacing of about 50 - 60 km almost in the direction of North-South (parallel to the trench axis). Two or more sets of tsunami meters and seismometers will be installed in one station for redundancy. Two sets of three component servo accelerometers, a set of three component quartz type accelerometers (frequency outputs), a set of three component velocity seismometers will be installed, and two sets of quartz type depth sensors (frequency outputs) will be installed as tsunami meters. Tsunami data and seismometer data will be digitized at sampling frequency of 10 Hz and 100 Hz, respectively, and will be added clock

  7. Recent developments in the setting up of the Malta Seismic Network

    NASA Astrophysics Data System (ADS)

    Agius, Matthew; Galea, Pauline; D'Amico, Sebastiano

    2015-04-01

    Weak to moderate earthquakes in the Sicily Channel have until now been either poorly located or left undetected. The number of seismic stations operated by various networks: Italy (INGV), Tunisia (TT), and Libya (LNSN) have now improved considerably, however most of the seismicity occurs offshore, in the central part of the Channel, away from the mainland stations. Seismic data availability from island stations across the Channel has been limited or had intermittent transmission hindering proper real-time earthquake monitoring and hypocentre relocation. In order to strengthen the seismic monitoring of the Sicily Channel, in particular the central parts of the Channel, the Seismic Monitoring and Research Unit (SMRU), University of Malta, has, in the last year, been installing a permanent seismic network across the Maltese archipelago: the Malta Seismic Network (ML). Furthermore the SMRU has upgraded its IT facilities to run a virtual regional seismic network composed of the stations on Pantelleria and Lampedusa, together with all the currently publicly available stations in the region. Selected distant seismic stations found elsewhere in the Mediterranean and across the globe have also been incorporated in the system in order to enhance the overall performance of the monitoring and to detect potentially damaging regional earthquakes. Data acquisition and processing of the seismic networks are run by SeisComP. The new installations are part of the project SIMIT (B1-2.19/11) funded by the Italia-Malta Operational Programme 2007-2013. The new system allows the SMRU to rapidly perform more accurate hypocentre locations in the region, and issue automatic SMS alert for potentially felt events in the Sicily Channel detected by the network and for strong earthquakes elsewhere. Within the SIMIT project, the alert system will include civil protection departments in Malta and Sicily. We present the recent developments of the real and virtual seismic network, and discuss the

  8. 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

  9. Micro-seismicity in Alberta recorded by the Canadian Rockies and Alberta Network

    NASA Astrophysics Data System (ADS)

    Schultz, R.; Gu, Y. J.

    2012-12-01

    Documented seismicity throughout Alberta, Canada has been relatively low in recent history, with fewer than fifteen events (ML > 3.5) recorded by the Geological Survey of Canada (GSC) since 1985. The notable lack of seismicity could be partially attributed to limited or intermittent station coverage in the province. For this reason, the Alberta Geological Survey (AGS) has been involved in a continued effort to maintain, improve and expand regional seismic networks. Broadband seismic data from the Canadian Rockies and Alberta Network (CRANE) and catalog excerpts from the Canadian National Seismic Network (CNSN) were analyzed. Micro-seismic hypocenters were located using Antelope, a software package from Boulder Real Time Technologies, Inc.. Analysis of data from September, 2006 to June, 2010 shows these events are typically naturally occurring or anthropogenic (e.g., mining blasts, which are not usually part of the earthquake catalogs). More than one hundred and twenty natural earthquakes were located in western and central Alberta, with the majority occurring along the Rocky Mountain foothills. During this period, earthquakes magnitudes (ML) ranging from 0.5 to 4.0 were measured and the magnitude of completeness is ~2.8 for this dataset. The substantial number of unreported events suggests that the existing earthquake catalogs, based exclusively on national seismic network stations, are incomplete. The addition of the CRANE dataset has improved the understanding of background seismicity by providing updated hypocenter locations and waveforms of more than thirty previously unrecorded earthquakes. Future endeavors to incorporate data from additional networks would prove invaluable for the identification of emergent trends or induced events.

  10. The gravitational resolving power of global seismic networks in the 0.1-10 Hz band

    NASA Astrophysics Data System (ADS)

    Mulargia, Francesco; Kamenshchik, Alexander

    2016-04-01

    Among the first attempts to detect gravitational waves, the seismic approach pre-dates the digital era. Major advances in computational power, seismic instrumentation and in the knowledge of seismic noise suggest to reappraise its potential. Using the whole earth as a detector, with the thousands of digital seismometers of seismic global networks as a single phased array, more than two decades of continuous seismic noise data are available and can be readily sifted at the only cost of (a pretty gigantic) computation. Using a subset of data, we show that absolute strains h ≲10-17 on burst gravitational pulses and h ≲10-21 on periodic signals may be feasibly resolved in the frequency range 0.1-10 Hz, only marginally covered by current advanced LIGO and future eLISA. However, theoretical predictions for the largest cosmic gravitational emissions at these frequencies are a few orders of magnitude lower.

  11. Peru Subduction Zone Seismic Experiment (PeruSZE): Preliminary Results From a Seismic Network Between Mollendo and Lake Titicaca, Peru.

    NASA Astrophysics Data System (ADS)

    Guy, R.; Stubailo, I.; Skinner, S.; Phillips, K.; Foote, E.; Lukac, M.; Aguilar, V.; Tavera, H.; Audin, L.; Husker, A.; Clayton, R.; Davis, P. M.

    2008-12-01

    This work describes preliminary results from a 50 station broadband seismic network recently installed from the coast to the high Andes in Peru. UCLA's Center for Embedded Network Sensing (CENS) and Caltech's Tectonic Observatory are collaborating with the IRD (French L'Institut de Recherche pour le Developpement) and the Institute of Geophysics, in Lima Peru in a broadband seismic experiment that will study the transition from steep to shallow slab subduction. The currently installed line has stations located above the steep subduction zone at a spacing of about 6 km. In 2009 we plan to install a line of 50 stations north from this line along the crest of the Andes, crossing the transition from steep to shallow subduction. A further line from the end of that line back to the coast, completing a U shaped array, is in the planning phase. The network is wirelessly linked using multi-hop network software designed by computer scientists in CENS in which data is transmitted from station to station, and collected at Internet drops, from where it is transmitted over the Internet to CENS each night. The instrument installation in Peru is almost finished and we have been receiving data daily from 10 stations (out of total 50) since June 2008. The rest are recording on-site while the RF network is being completed. The software system provides dynamic link quality based routing, reliable data delivery, and a disruption tolerant shell interface for managing the system from UCLA without the need to travel to Peru. The near real-time data delivery also allows immediate detection of any problems at the sites. We are building a seismic data and GPS quality control toolset that would greatly minimize the station's downtime by alerting the users of any possible problems.

  12. Dual simulations of fluid flow and seismic wave propagation in a fractured network: effects of pore pressure on seismic signature

    NASA Astrophysics Data System (ADS)

    Vlastos, S.; Liu, E.; Main, I. G.; Schoenberg, M.; Narteau, C.; Li, X. Y.; Maillot, B.

    2006-08-01

    Fluid flow in the Earth's crust plays an important role in a number of geological processes. In relatively tight rock formations such flow is usually controlled by open macrofractures, with significant implications for ground water flow and hydrocarbon reservoir management. The movement of fluids in the fractured media will result in changes in the pore pressure and consequently will cause changes to the effective stress, traction and elastic properties. The main purpose of this study is to numerically examine the effect of pore pressure changes on seismic wave propagation (i.e. the effects of pore pressures on amplitude, arrival time, frequency content). This is achieved by using dual simulations of fluid flow and seismic propagation in a common 2-D fracture network. Note that the dual simulations are performed separately as the coupled simulations of fluid flow and seismic wave propagations in such fracture network is not possible because the timescales of fluid flow and wave propagation are considerably different (typically, fluid flows in hours, whereas wave propagation in seconds). The flow simulation updates the pore pressure at consecutive time steps, and thus the elastic properties of the rock, for the seismic modelling. In other words, during each time step of the flow simulations, we compute the elastic response corresponding to the pore pressure distribution. The relationship between pore pressure and fractures is linked via an empirical relationship given by Schoenberg and the elastic response of fractures is computed using the equivalent medium theory described by Hudson and Liu. Therefore, we can evaluate the possibility of inferring the changes of fluid properties directly from seismic data. Our results indicate that P waves are not as sensitive to pore pressure changes as S and coda (or scattered) waves. The increase in pore pressure causes a shift of the energy towards lower frequencies, as shown from the spectrum (as a result of scattering

  13. Neural network models for earthquake magnitude prediction using multiple seismicity indicators.

    PubMed

    Panakkat, Ashif; Adeli, Hojjat

    2007-02-01

    Neural networks are investigated for predicting the magnitude of the largest seismic event in the following month based on the analysis of eight mathematically computed parameters known as seismicity indicators. The indicators are selected based on the Gutenberg-Richter and characteristic earthquake magnitude distribution and also on the conclusions drawn by recent earthquake prediction studies. Since there is no known established mathematical or even empirical relationship between these indicators and the location and magnitude of a succeeding earthquake in a particular time window, the problem is modeled using three different neural networks: a feed-forward Levenberg-Marquardt backpropagation (LMBP) neural network, a recurrent neural network, and a radial basis function (RBF) neural network. Prediction accuracies of the models are evaluated using four different statistical measures: the probability of detection, the false alarm ratio, the frequency bias, and the true skill score or R score. The models are trained and tested using data for two seismically different regions: Southern California and the San Francisco bay region. Overall the recurrent neural network model yields the best prediction accuracies compared with LMBP and RBF networks. While at the present earthquake prediction cannot be made with a high degree of certainty this research provides a scientific approach for evaluating the short-term seismic hazard potential of a region. PMID:17393560

  14. Evolution and strengthening of the Calabrian Regional Seismic Network during the Pollino sequence

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Antonino; Gervasi, Anna; Guerra, Ignazio

    2013-04-01

    In the last three years the Calabria-Lucania border area is affected by an intense seismic activity generated by the activation of geological structures which be seat of clusters of microearthquakes, with energy release sufficient to be felt and to generate alarm and bother. Besides to the historical memory of the inhabitants of Mormanno (the town most affected of macroseismic effects) there are some historical documents that indicate the occurrence of a similar seismic crisis in 1888. A more recent seismic sequence, the first monitored by seismic instruments, occurred in 1973-1974. In the last case, the activity started in early 2010 and is still ongoing. The two shocks of ML = 4.3 and 5.0 and the the very long time duration differs this crisis from the previous ones. Given this background, in 1981 was installed at Mormanno a seismic station (MMN) belonging to Regional Seismic Network of the University of Calabria (RSRC), now also a station of the Italian National Seismic Network of the Istituto Nazionale di Geofisica Vulcanolgia (INSN-INGV). This seismic station made it possible to follow the evolution of seismicity in this area and in particular the progressive increase in seismic activity started in 2010. Since 2010, some 3D stand-alone, was installed by the University of Calabria. Further stations of INGV were installed in November 2011 after a sharp increase of the energy release and subsequently by the INGV and the GeoForschungsZentrum (Potsdam) after the main shock of the whole sequence. Seismic networks are powerful tools for understanding active tectonic processes in a monitored seismically active region. However, the optimal monitoring of a seismic region requires the assessment of the seismic network capabilities to identify seismogenic areas that are not adequately covered and to quantify measures that will allow the network improvement. In this paper we examine in detail the evolution and the strengthening of the RSRC in the last years analyzing the

  15. Near real-time detection and characterization of landslides using broadband seismic networks

    NASA Astrophysics Data System (ADS)

    Manconi, Andrea; Coviello, Velio; De Santis, Francesca; Picozzi, Matteo

    2015-04-01

    Broadband seismic networks at regional, national, and global scale are usually deployed for a specific purpose, i.e. earthquake monitoring. However, it has been recently demonstrated that these networks are also capable to efficiently detect failure and transport processes related to landslide phenomena. Indeed, stations located several tens of kilometers away from the source areas can record the ground vibrations produced by large mass movements. In this work, we propose an integrated approach for the near real-time detection, location, and characterization of landslides, by considering data acquired from the Italian broadband seismic networks and available in the European Integrated Data Archive (EIDA). We use an automatic picking of first arrivals to identify significant seismic events recorded by the monitoring network. Secondly, waveforms relevant to landslide phenomena are selected by analyzing the spectral characteristics of seismic signals, which significantly differ from those related to earthquake events. Afterwards, in order to locate the landslide, we use a modified version of the real-time evolutionary location algorithm proposed for earthquakes, which relies on geometrical characteristics of the seismic network and on the relationships between triggered stations and not-triggered stations. Indeed, a first landslide location is roughly estimated as soon as the first station is triggered. The progressive increase over time in the number of triggered stations allows improving the accuracy on the most likely landslide location. Finally, we analyze the seismic energy released to infer an approximate value of the landslide volume in near real time. Here we present few examples relevant to recent well-known landslides where our method was successfully applied. Our results show how it is possible to extract precious information for landslide hazard assessment from seismic monitoring data, which in the field of earthquake warning would be discarded. Moreover

  16. Social Media as Seismic Networks for the Earthquake Damage Assessment

    NASA Astrophysics Data System (ADS)

    Meletti, C.; Cresci, S.; La Polla, M. N.; Marchetti, A.; Tesconi, M.

    2014-12-01

    The growing popularity of online platforms, based on user-generated content, is gradually creating a digital world that mirrors the physical world. In the paradigm of crowdsensing, the crowd becomes a distributed network of sensors that allows us to understand real life events at a quasi-real-time rate. The SoS-Social Sensing project [http://socialsensing.it/] exploits the opportunistic crowdsensing, involving users in the sensing process in a minimal way, for social media emergency management purposes in order to obtain a very fast, but still reliable, detection of emergency dimension to face. First of all we designed and implemented a decision support system for the detection and the damage assessment of earthquakes. Our system exploits the messages shared in real-time on Twitter. In the detection phase, data mining and natural language processing techniques are firstly adopted to select meaningful and comprehensive sets of tweets. Then we applied a burst detection algorithm in order to promptly identify outbreaking seismic events. Using georeferenced tweets and reported locality names, a rough epicentral determination is also possible. The results, compared to Italian INGV official reports, show that the system is able to detect, within seconds, events of a magnitude in the region of 3.5 with a precision of 75% and a recall of 81,82%. We then focused our attention on damage assessment phase. We investigated the possibility to exploit social media data to estimate earthquake intensity. We designed a set of predictive linear models and evaluated their ability to map the intensity of worldwide earthquakes. The models build on a dataset of almost 5 million tweets exploited to compute our earthquake features, and more than 7,000 globally distributed earthquakes data, acquired in a semi-automatic way from USGS, serving as ground truth. We extracted 45 distinct features falling into four categories: profile, tweet, time and linguistic. We run diagnostic tests and

  17. The Quake-Catcher Network: A Seismic Network for the World

    NASA Astrophysics Data System (ADS)

    Lawrence, J. F.; Cochran, E. S.; Christensen, C. M.; Chung, A. I.

    2012-12-01

    The Quake-Catcher Network (QCN) is a collaborative initiative for developing the world's largest, low-cost strong-motion seismic network by utilizing sensors in and attached to volunteer internet-connected computers. QCN is not only a research tool, but provides an educational tool for teaching earthquake science in formal and informal environments. A central mission of the QCN is to provide scientific educational software and hardware so that K-12 teachers, students, and the general public can better understand and participate in the science of earthquakes and earthquake hazards. The QCN now has over 2000 volunteers worldwide, with concentrations in various earthquake-prone metropolitan areas. The sensors have recorded earthquakes with magnitudes between Ml2.5 (Christchurch, New Zealand - 2010) and Mw8.8 (Maule, Chile - 2010). The peak ground accelerations (PGAs) exhibit the same distribution of scatter as traditional seismic sensors (e.g. the Kinemetrics Epicensor) but with poor resolution at the bottom end. Real-time distributed computing allows for rapid earthquake location and characterization, including magnitude estimation and AlertMap generation. The network is installed and maintained by volunteer seismologists around the world. Because the volunteer provides a free computational platform (a personal computer), internet access, and shelter, the costs of the Quake-Catcher Network are minimal. QCN provides free sensors for individuals and organizations in key regions of interest. QCN provides subsidized sensors (5) for K-12 teachers in the US. QCN provides subsidized sensor at 49 for the general public and $5 for K-12 teachers in the United States. International collaborators are expanding the regions of coverage around the world. With your help, the Quake-Catcher Network can provide better understanding of earthquakes for scientists and the general public. To learn more, visit http://qcn.stanford.edu.arthquake detected near Los Angeles, California on the

  18. 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

  19. UNIBRA - the German contribution to the AlpArray Seismic Network

    NASA Astrophysics Data System (ADS)

    Friederich, Wolfgang; Korn, Michael; Meier, Thomas; Plenefisch, Thomas; Ritter, Joachim; Rümpker, Georg; Thomas, Christine; Tilmann, Frederik; Wassermann, Joachim

    2016-04-01

    AlpArray is a European initiative to advance our understanding of orogenesis and its relationship to mantle dynamics, plate reorganizations, surface processes and seismic hazard in the Alps-Apennines-Carpathians-Dinarides orogenic system (cited from the AlpArray Science Plan). The core of the AlpArray project is a dense seismic network covering the entire Alpine region including its forelands. The network is composed of about 600 broadband seismic sensors of which 280 are operated permanently by national institutions and the remaining 320 are deployed temporarily by project partners for a time span of at least 2 years. In a joint effort, German universities contribute 71 temporary stations to the AlpArray Seismic Network, of which 55 are located in southern Germany and 16 in Austria. The instrumentation of the stations is heterogeneous and comprises Streckeisen, Nanometrics and Guralp sensors operated with EarthData, Nanometrics and Quanterra data loggers. The instruments are installed in remote areas and rarely used buildings with power supply. Some stations transfer data via mobile internet connection. The data will be collected at national EIDA centers which also serve as nodes for dissemination of data to the members of the AlpArray working group. Here, we describe installation procedures and setting of the German UNIBRA (UNIversity BRoadband Array) stations. In addition, we present noise characteristics and first records of teleseismic earthquakes. The descriptions may serve as a reference for later work with data from the AlpArray Seismic Network.

  20. Testing and optimization of the seismic networks of Campi Flegrei (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Tramelli, A.; Troise, C.; De Natale, G.; Orazi, M.

    2013-11-01

    The definition of the network resolution power is an important parameter to be considered when evaluating most of the seismic analysis, being connected to the location quality and earthquakes detectability. We estimated the resolving power of the seismic network of Campi Flegrei. The results show that the actual moment magnitude threshold is 0.5 in the Solfatara area, center of the caldera, but increases sharply going away from the center. We also estimated the theoretical resolution power of the actual seismic network of Campi Flegrei plus 5 hypothetical borehole stations, moving the borehole stations into 3 different wells. As expected, big improvements in the location parameters come from the use of borehole stations. The results show that a 3000 m deep borehole located close to the actual hypocentral area would allow to detect and locate the very low magnitude earthquakes, probably connected to the hydrothermal system characterizing the Campi Flegrei caldera. Finally, we performed an optimization analysis of the permanent seismic network of Campi Flegrei finding the best 3 station positions that would increase the resolution power of the network to locate earthquakes in the South and offshore part of the caldera. We evidenced that the actual network has an improvable resolution in the South and West part of the caldera.

  1. Sandia`s network for Supercomputing `94: Linking the Los Alamos, Lawrence Livermore, and Sandia National Laboratories using switched multimegabit data service

    SciTech Connect

    Vahle, M.O.; Gossage, S.A.; Brenkosh, J.P.

    1995-01-01

    Supercomputing `94, a high-performance computing and communications conference, was held November 14th through 18th, 1994 in Washington DC. For the past four years, Sandia National Laboratories has used this conference to showcase and focus its communications and networking endeavors. At the 1994 conference, Sandia built a Switched Multimegabit Data Service (SMDS) network running at 44.736 megabits per second linking its private SMDS network between its facilities in Albuquerque, New Mexico and Livermore, California to the convention center in Washington, D.C. For the show, the network was also extended from Sandia, New Mexico to Los Alamos National Laboratory and from Sandia, California to Lawrence Livermore National Laboratory. This paper documents and describes this network and how it was used at the conference.

  2. Seismic Signal Classification with Offshore/Amphibious Networks Using an Artificial Neural Network

    NASA Astrophysics Data System (ADS)

    Williams, M. C.; Trehu, A. M.

    2011-12-01

    The amphibious Central Oregon Locked Zone Array (COLZA) of seismic stations was deployed from 2007-2009 to record earthquakes occurring in the seismogenic zone offshore central Oregon. This array included two year-long deployments of ocean bottom seismometers (OBS's) from the NSF OBSIP. In addition to local and distant earthquakes, the OBS array recorded thousands of impulsive local signals, which are not easily filtered out by a standard STA/LTA detection algorithm. Many of these signals are likely of biological origin (informally referred to as "bio-bumps"). These signals have a wide range of amplitudes, can mask local earthquake phase arrivals, and make automatic detection more difficult. We show that signal characteristics derived from 3-component seismic data at each station can be used to filter out event detections that are unlikely to be earthquake-generated. A decision-making algorithm is run using a joint set of signal characteristics to identify possible local events and classify detections that are likely to be "bumps". We present results on the effectiveness of this classification technique using various combinations of input parameters applied to the onshore/offshore COLZA array dataset. The classification algorithm is a multilayer perceptron (MLP) artificial neural network, trained through backpropagation using human-identified examples of both earthquake phases and impulsive "bumps". The effectiveness of a neural network is highly dependent on the data space consisting of the inputs calculated for each signal, which represent its main characteristics and differentiate it from other events. As inputs to the neural network, for each event detection, in addition to the STA/LTA value, we determine three signal characteristics from 3-component waveform data: the variance of the power cepstrum calculated from a portion of the signal spectrum, the rectilinearity of particle motion, and the ratio of particle motion orthogonal to the principle direction of

  3. Ghana's experience in the establishment of a national digital seismic network observatory

    NASA Astrophysics Data System (ADS)

    Ahulu, Sylvanus; Danuor, Sylvester Kojo

    2015-07-01

    The Government of Ghana has established a National Digital Seismic Network Observatory in Ghana with the aim of monitoring events such as earthquakes, blasts from mining and quarrying, nuclear tests, etc. The Digital Observatory was commissioned on 19 December 2012, and was dedicated to Geosciences in Ghana. Previously Ghana did not have any operational, digital seismic network acquisition system with the capability of monitoring and analysing data for planning and research purposes. The Ghana Geological Survey has been monitoring seismic events with an analogue system which was not efficient and does not deliver real-time data. Hence, the importance of setting up the National Digital Seismic Network System which would enable the Geological Survey to constantly monitor, manage and coordinate both natural and man-made seismic activities in the country and around the globe, to some extent on real-time basis. The Network System is made up of six remote digital stations that transmit data via satellite to the central observatory. Sensors used are 3× Trillium Compact and 3× Trillium 120PA with Trident digitizers. The department has also acquired strong motion equipment: Titan accelerometers with Taurus digitizers from Nanometrics. Three of each of these instruments have been installed at the Akosombo and Kpong hydrodams, and also at the Weija water supply dam. These instruments are used to monitor dams. The peak ground acceleration (PGA) values established from the analysed data from the accelerometers will be used to retrofit or carry out maintenance work of the dam structures to avoid collapse. Apart from these, the observatory also assesses and analyses seismic waveforms relevant to its needs from the Global Seismographic Network (GSN) system operated by the US Geological Survey. The Ghana Geological Survey, through its Seismic Network Observatory makes data available to its stakeholder institutions for earthquake disaster mitigation; reports on all aspects of

  4. Autonomous telemetry system by using mobile networks for a long-term seismic observation

    NASA Astrophysics Data System (ADS)

    Hirahara, S.; Uchida, N.; Nakajima, J.

    2012-04-01

    When a large earthquake occurs, it is important to know the detailed distribution of aftershocks immediately after the main shock for the estimation of the fault plane. The large amount of seismic data is also required to determine the three-dimensional seismic velocity structure around the focal area. We have developed an autonomous telemetry system using mobile networks, which is specialized for aftershock observations. Because the newly developed system enables a quick installation and real-time data transmission by using mobile networks, we can construct a dense online seismic network even in mountain areas where conventional wired networks are not available. This system is equipped with solar panels that charge lead-acid battery, and enables a long-term seismic observation without maintenance. Furthermore, this system enables a continuous observation at low costs with flat-rate or prepaid Internet access. We have tried to expand coverage areas of mobile communication and back up Internet access by configuring plural mobile carriers. A micro server embedded with Linux consists of automatic control programs of the Internet connection and data transmission. A status monitoring and remote maintenance are available via the Internet. In case of a communication failure, an internal storage can back up data for two years. The power consumption of communication device ranges from 2.5 to 4.0 W. With a 50 Ah lead-acid battery, this system continues to record data for four days if the battery charging by solar panels is temporarily unavailable.

  5. Location Performance and Detection Threshold of the Spanish National Seismic Network

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Antonino; Badal, José; D'Anna, Giuseppe; Papanastassiou, Dimitris; Baskoutas, Ioannis; Özel, Nurcan M.

    2013-11-01

    Spain is a low-to-moderate seismicity area with relatively low seismic hazard. However, several strong shallow earthquakes have shaken the country causing casualties and extensive damage. Regional seismicity is monitored and surveyed by means of the Spanish National Seismic Network, maintenance and control of which are entrusted to the Instituto Geográfico Nacional. This array currently comprises 120 seismic stations distributed throughout Spanish territory (mainland and islands). Basically, we are interested in checking the noise conditions, reliability, and seismic detection capability of the Spanish network by analyzing the background noise level affecting the array stations, errors in hypocentral location, and detection threshold, which provides knowledge about network performance. It also enables testing of the suitability of the velocity model used in the routine process of earthquake location. To perform this study we use a method that relies on P and S wave travel times, which are computed by simulation of seismic rays from virtual seismic sources placed at the nodes of a regular grid covering the study area. Given the characteristics of the seismicity of Spain, we drew maps for M L magnitudes 2.0, 2.5, and 3.0, at a focal depth of 10 km and a confidence level 95 %. The results relate to the number of stations involved in the hypocentral location process, how these stations are distributed spatially, and the uncertainties of focal data (errors in origin time, longitude, latitude, and depth). To assess the extent to which principal seismogenic areas are well monitored by the network, we estimated the average error in the location of a seismic source from the semiaxes of the ellipsoid of confidence by calculating the radius of the equivalent sphere. Finally, the detection threshold was determined as the magnitude of the smallest seismic event detected at least by four stations. The northwest of the peninsula, the Pyrenees, especially the westernmost segment

  6. A model for a seismic computerized alert network

    USGS Publications Warehouse

    Heaton, T.H.

    1985-01-01

    In large earthquakes, damaging ground motions may occur at large epicentral distances. Because of the relatively slow speed of seismic waves, it is possible to construct a system to provide short-term warning (as much as several tens of seconds) of imminent strong ground motions from major earthquakes. Automated safety responses could be triggered by users after receiving estimates of the arrival time and strength of shaking expected at an individual site. Although warning times are likely to be short for areas greatly damaged by relatively numerous earthquakes of moderate size, large areas that experience very strong shaking during great earthquakes would receive longer warning times.

  7. A model for a seismic computerized alert network.

    PubMed

    Heaton, T H

    1985-05-24

    In large earthquakes, damaging ground motions may occur at large epicentral distances. Because of the relatively slow speed of seismic waves, it is possible to construct a system to provide short-term warning (as much as several tens of seconds) of imminent strong ground motions from major earthquakes. Automated safety responses could be triggered by users after receiving estimates of the arrival time and strength of shaking expected at an individual site. Although warning times are likely to be short for areas greatly damaged by relatively numerous earthquakes of moderate size, large areas that experience very strong shaking during great earthquakes would receive longer warning times. PMID:17797662

  8. Seismic network detection capability within the natural gas fields in Northern Germany

    NASA Astrophysics Data System (ADS)

    Gestermann, Nicolai; Plenefisch, Thomas

    2016-04-01

    The Northern German basin is a tectonic region of relatively low seismic activity with only singular and weak tectonic events. However, during the last decades seismicity raised in the vicinity of the natural gas fields. Due to the spatial vicinity of the epicenters to the operated gas fields and their appearance starting after the beginning of extraction they are ranked as induced events. The epicenters of these events extend 50 km NS and 400 km EW from the border to the Netherlands in the West to Altmark region in the East. Altogether, 63 events with ML 0.5 to 4.5 were detected between 1977 and 2015. Many of them were felt by parts of the inhabitants up to 15 km from the epicenter whereas the strongest one, the magnitude 4.5 event close to the village of Rotenburg on 20th October 2004, was even felt in Hamburg as far as 65 km from the epicenter. Several new installed surface and borehole stations have recently improved the monitoring capabilities in the region. The station network design and number of station varied significantly during the last years and only a few seismic stations were operational over the entire period. This variability was not taken into account for the assessment of the seismicity like the b-value and completeness. For some of the areas it is still difficult to detect and analyze events with magnitude below 2 due to bad noise conditions invoked by the thick sediments as well as to the relatively large area to be covered. Up to now, it is not clear whether the small number of fore- and aftershocks is an inherent characteristic of the induced events and thereby different from tectonic earthquake sequences or only the effect of the non appropriate seismic surveillance during the last decades. Seismicity in a low magnitude range could not be detected in some of the areas but should exist if the Gutenberg-Richter relation is valid. The detection capability can be one of the reasons and is now estimated for the main active areas as a function of

  9. Seismic network detection probability assessment using waveforms and accounting to event association logic

    NASA Astrophysics Data System (ADS)

    Pinsky, Vladimir; Shapira, Avi

    2016-05-01

    The geographical area where a seismic event of magnitude M ≥ M t is detected by a seismic station network, for a defined probability is derived from a station probability of detection estimated as a function of epicentral distance. The latter is determined from both the bulletin data and the waveforms recorded by the station during the occurrence of the event with and without band-pass filtering. For simulating the real detection process, the waveforms are processed using the conventional Carl Johnson detection and association algorithm. The attempt is presented to account for the association time criterion in addition to the conventional approach adopted by the known PMC method.

  10. UMTS rapid response real-time seismic networks: implementation and strategies at INGV

    NASA Astrophysics Data System (ADS)

    Govoni, A.; Margheriti, L.; Moretti, M.; Lauciani, V.; Sensale, G.; Bucci, A.; Criscuoli, F.

    2015-12-01

    Universal Mobile Telecommunications System (UMTS) and its evolutions are nowadays the most affordable and widespread data communication infrastructure available almost world wide. Moreover the always growing cellular phone market is pushing the development of new devices with higher performances and lower power consumption. All these characteristics make UMTS really useful for the implementation of an "easy to deploy" temporary real-time seismic station. Despite these remarkable features, there are many drawbacks that must be properly taken in account to effectively transmit the seismic data: Internet security, signal and service availability, power consumption. - Internet security: exposing seismological data services and seismic stations to the Internet is dangerous, attack prone and can lead to downtimes in the services, so we setup a dedicated Virtual Private Network (VPN) service to protect all the connected devices. - Signal and service availability: while for temporary experiment a carefull planning and an accurate site selection can minimize the problem, this is not always the case with rapid response networks. Moreover, as with any other leased line, the availability of the UMTS service during a seismic crisis is basically unpredictable. Nowadays in Italy during a major national emergency a Committee of the Italian Civil Defense ensures unified management and coordination of emergency activities. Inside it the telecom companies are committed to give support to the crisis management improving the standards in their communication networks. - Power consumption: it is at least of the order of that of the seismic station and, being related to data flow and signal quality is largely unpredictable. While the most secure option consists in adding a second independent solar power supply to the seismic station, this is not always a very convenient solution since it doubles the cost and doubles the equipment on site. We found that an acceptable trade-off is to add an

  11. Utah's Regional/Urban ANSS Seismic Network---Strategies and Tools for Quality Performance

    NASA Astrophysics Data System (ADS)

    Burlacu, R.; Arabasz, W. J.; Pankow, K. L.; Pechmann, J. C.; Drobeck, D. L.; Moeinvaziri, A.; Roberson, P. M.; Rusho, J. A.

    2007-05-01

    The University of Utah's regional/urban seismic network (224 stations recorded: 39 broadband, 87 strong-motion, 98 short-period) has become a model for locally implementing the Advanced National Seismic System (ANSS) because of successes in integrating weak- and strong-motion recording and in developing an effective real-time earthquake information system. Early achievements included implementing ShakeMap, ShakeCast, point-to- multipoint digital telemetry, and an Earthworm Oracle database, as well as in-situ calibration of all broadband and strong-motion stations and submission of all data and metadata into the IRIS DMC. Regarding quality performance, our experience as a medium-size regional network affirms the fundamental importance of basics such as the following: for data acquisition, deliberate attention to high-quality field installations, signal quality, and computer operations; for operational efficiency, a consistent focus on professional project management and human resources; and for customer service, healthy partnerships---including constant interactions with emergency managers, engineers, public policy-makers, and other stakeholders as part of an effective state earthquake program. (Operational cost efficiencies almost invariably involve trade-offs between personnel costs and the quality of hardware and software.) Software tools that we currently rely on for quality performance include those developed by UUSS (e.g., SAC and shell scripts for estimating local magnitudes) and software developed by other organizations such as: USGS (Earthworm), University of Washington (interactive analysis software), ISTI (SeisNetWatch), and IRIS (PDCC, BUD tools). Although there are many pieces, there is little integration. One of the main challenges we face is the availability of a complete and coherent set of tools for automatic and post-processing to assist in achieving the goals/requirements set forth by ANSS. Taking our own network---and ANSS---to the next level

  12. Leveraging EarthScope USArray with the Central and Eastern United States Seismic Network

    NASA Astrophysics Data System (ADS)

    Busby, R.; Sumy, D. F.; Woodward, R.; Frassetto, A.; Brudzinski, M.

    2015-12-01

    Recent earthquakes, such as the 2011 M5.8 Mineral, Virginia earthquake, raised awareness of the comparative lack of knowledge about seismicity, site response to ground shaking, and the basic geologic underpinnings in this densely populated region. With this in mind, the National Science Foundation, United States Geological Survey, United States Nuclear Regulatory Commission, and Department of Energy supported the creation of the Central and Eastern United States Seismic Network (CEUSN). These agencies, along with the IRIS Consortium who operates the network, recognized the unique opportunity to retain EarthScope Transportable Array (TA) seismic stations in this region beyond the standard deployment duration of two years per site. The CEUSN project supports 159 broadband TA stations, more than 30 with strong motion sensors added, that are scheduled to operate through 2017. Stations were prioritized in regions of elevated seismic hazard that have not been traditionally heavily monitored, such as the Charlevoix and Central Virginia Seismic Zones, and in regions proximal to nuclear power plants and other critical facilities. The stations (network code N4) transmit data in real time, with broadband and strong motion sensors sampling at 100 samples per second. More broadly the CEUSN concept also recognizes the existing backbone coverage of permanently operating seismometers in the CEUS, and forms a network of over 300 broadband stations. This multi-agency collaboration is motivated by the opportunity to use one facility to address multiple missions and needs in a way that is rarely possible, and to produce data that enables both researchers and federal agencies to better understand seismic hazard potential and associated seismic risks. In June 2015, the CEUSN Working Group (www.usarray.org/ceusn_working_group) was formed to review and provide advice to IRIS Management on the performance of the CEUSN as it relates to the target scientific goals and objectives. Map shows

  13. An improved real-time seismic network in the Central Mediterranean

    NASA Astrophysics Data System (ADS)

    Agius, Matthew; Galea, Pauline; D'Amico, Sebastiano

    2014-05-01

    The Central Mediterranean is a region of active tectonics characterised by the interaction of a number of varied and sometimes poorly understood processes. Superimposed on the convergent scenario of the African plate pushing northwestward, a NE-SW directed extensional regime is active in the Sicily Channel, expressed in the form of a seismically active east-west trending system of strike-slip lineaments and a series of pull-apart grabens. The offshore seismicity of the Sicily channel, generally limited to magnitudes below 4.5, is normally difficult to quantify precisely, due to poor station coverage, yet it is believed that its analysis will considerably improve our understanding of the processes affecting the region. We present recent improvements to real and virtual seismic networking in the Central Mediterranean, based at the Seismic Monitoring and Research Unit (SMRU), University of Malta. Within the project SIMIT (B1-2.19/11) funded by the Italia-Malta Operational Programme 2007-2013, earthquake monitoring on the Maltese Islands is being upgraded through the installation of a further two broadband stations, one of which will be on the smaller island of Gozo. A new network, ML (Malta Seismic Network), has been internationally registered with the FDSN. At the same time, the installation and implementation of SeisComP3 has enabled the setting up of a virtual, real-time Central Mediterranean network, made up of 18 stations in Southern Italy (including Sicily, Lampedusa and Pantelleria) belonging to the Istituto Nazionale di Geofisica e Vulcanologia, 3 stations in Tunisia (National Institute of Meteorology of Tunisia) and the 3 stations on the Maltese Islands. This will allow us to rapidly perform more accurate hypocentral locations in the region. The virtual network, which also incorporates a number of more distant stations, has been tuned to issue SMS alerts for potentially felt events in the Sicily Channel detected by the network, and for strong earthquakes

  14. Strain Rate by Geodetic Observations Associated with Seismic Events in the SIRGAS-CON Network Region.

    NASA Astrophysics Data System (ADS)

    Marotta, G. S.; Franca, G.; Galera Monico, J. F.; Fuck, R. A.

    2014-12-01

    This research investigates surface strains related to seismic events and their relationship with pre- and post-seismic events in South American, Antarctica, Nazca, Cocos, North American and Caribbean plates , by analyzing the variation of estimated earth coordinates, for the period 2000-2014, supplied by a geodetic network called SIRGAS-CON. Based on data provided by the USGS for the same period, and after the Global Congruency test, we selected the events associated with unstable geodetic network points. The resulting strains were estimated based on the finite element method. It was possible to determine the strains along with the resulting guidelines for pre- and post-seismic, considering each region formed for analysis as a homogeneous solid body. Later, a multi-year solution of the network was estimated and used to estimate the strain rates of the earth surface from the changing directions of the velocity vectors of 332 geodetic points located in the South American plate and surround plates. The strain rate was determined and, using Euler vector computed, it was possible to estimate the convergence and accommodation rates to each plate. The results showed that contraction regions coincide with locations with most of the high magnitude seismic events. It suggest that major movements detected on the surface occur in regions with more heterogeneous geological structures and multiple rupture events; significant amounts of elastic strain can be accumulated on geological structures away from the plate boundary faults; and, behavior of contractions and extensions is similar to what has been found in seismological studies. Despite the association between seismic events and the strain of geodetic network, some events of high magnitude were excluded because it does not show the surface strain, which is located at great depths. It was confirmed that events of greater magnitude provide increased surface strain rate when compared with other similar depths.

  15. UMTS rapid response real-time seismic networks: implementation and strategies at INGV

    NASA Astrophysics Data System (ADS)

    Govoni, Aladino; Margheriti, Lucia; Moretti, Milena; Lauciani, Valentino; Sensale, Gianpaolo; Bucci, Augusto; Criscuoli, Fabio

    2015-04-01

    The benefits of portable real-time seismic networks are several and well known. During the management of a temporary experiment from the real-time data it is possible to detect and fix rapidly problems with power supply, time synchronization, disk failures and, most important, seismic signal quality degradation due to unexpected noise sources or sensor alignment/tampering. This usually minimizes field maintenance trips and maximizes both the quantity and the quality of the acquired data. When the area of the temporary experiment is not well monitored by the local permanent network, the real-time data from the temporary experiment can be fed to the permanent network monitoring system improving greatly both the real-time hypocentral locations and the final revised bulletin. All these benefits apply also in case of seismic crises when rapid deployment stations can significantly contribute to the aftershock analysis. Nowadays data transmission using meshed radio networks or satellite systems is not a big technological problem for a permanent seismic network where each site is optimized for the device power consumption and is usually installed by properly specialized technicians that can configure transmission devices and align antennas. This is not usually practical for temporary networks and especially for rapid response networks where the installation time is the main concern. These difficulties are substantially lowered using the now widespread UMTS technology for data transmission. A small (but sometimes power hungry) properly configured device with an omnidirectional antenna must be added to the station assembly. All setups are usually configured before deployment and this allows for an easy installation also by untrained personnel. We describe here the implementation of a UMTS based portable seismic network for both temporary experiments and rapid response applications developed at INGV. The first field experimentation of this approach dates back to the 2009 L

  16. Estimation of gas hydrate saturation in the Ulleung basin using seismic attributes and a neural network

    NASA Astrophysics Data System (ADS)

    Jeong, Taekju; Byun, Joongmoo; Choi, Hyungwook; Yoo, Donggeun

    2014-07-01

    Among the unconventional natural resources, gas hydrates have recently received much attention as a promising potential energy source. To develop gas hydrates, their distribution and saturation should be estimated, preferentially at the initial stage of development. In most cases, the distribution of gas hydrates can be identified by using seismic indicators including a bottom simulating reflector (BSR) and chimney/column structures, which indirectly determine the presence of gas hydrate. However, these indicators can be used only when they appear on a seismic image. Because the saturation of gas hydrate is generally calculated by using well logs, the information is limited to the well location. To overcome these limitations, seismic impedance inversion and neural network methods can be used. Seismic inversion enables the identification of a gas hydrate reservoir even if seismic indicators do not exist, and a neural network makes it possible to predict the gas hydrate saturation in a region of interest away from the wells by combining well logging data and other attributes extracted from the seismic data. In this study, to estimate the distribution and saturation of gas hydrates that are broadly distributed in the Ulleung basin of the East Sea, seismic inversions such as acoustic impedance (AI), shear impedance (SI), and elastic impedance (EI) were calculated, and then the seismic attributes (ratio of compressional wave velocity to shear wave velocity, Vp/Vs, and combinations of Lamé parameters, λρ and μρ) that have unique features in hydrated sediments were extracted. Gas-hydrate-bearing sediments displayed high AI, high SI, high EI (22.5°), low Vp/Vs ratio, high λρ, and high μρ compared the surrounding sediments. The sediments containing free gas displayed low AI, low SI, low EI (22.5°), high Vp/Vs ratio, low λρ, and low μρ due to the phase transition from gas hydrate to gas. By combining these findings, the distribution of gas hydrates was

  17. Seismicity at the convergent plate boundary offshore Crete, Greece, observed by an amphibian network

    NASA Astrophysics Data System (ADS)

    Becker, D.; Meier, T.; Bohnhoff, M.; Harjes, H.-P.

    2010-04-01

    We investigate microseismic activity at the convergent plate boundary of the Hellenic subduction zone on- and offshore south-eastern Crete with unprecedented precision using recordings from an amphibian seismic network. The network configuration consisted of up to eight ocean bottom seismometers as well as five temporary short-period and six permanent broadband stations on Crete and surrounding islands. More than 2,500 local and regional events with magnitudes up to M L = 4.5 were recorded during the time period July 2003-June 2004. The magnitude of completeness varies between 1.5 on Crete and adjacent areas and increases to 2.5 in the vicinity of the Strabo trench 100 km south of Crete. Tests with different localization schemes and velocity models showed that the best results were obtained from a probabilistic earthquake localization using a 1-D velocity model and corresponding station corrections obtained by simultaneous inversion. Most of the seismic activity is located offshore of central and eastern Crete and interpreted to be associated with the intracrustal graben system (Ptolemy and Pliny trenches). Furthermore, a significant portion of events represents interplate seismicity along the NNE-ward dipping plate interface. The concentration of seismicity along the Ptolemy and Pliny trenches extends from shallow depths down to the plate interface and indicates active movement. We propose that both trenches form transtensional structures within the Aegean plate. The Aegean continental crust between these two trenches is interpreted as a forearc sliver as it exhibits only low microseismic activity during the observation period and little or no internal deformation. Interplate seismicity between the Aegean and African plates forms a 100-km wide zone along dip from the Strabo trench in the south to the southern shore-line of Crete in the north. The seismicity at the plate contact is randomly distributed and no indications for locked zones were observed. The plate

  18. The Central and Eastern U.S. Seismic Network: Legacy of USArray

    NASA Astrophysics Data System (ADS)

    Eakins, J. A.; Astiz, L.; Benz, H.; Busby, R. W.; Hafner, K.; Reyes, J. C.; Sharer, G.; Vernon, F.; Woodward, R.

    2014-12-01

    As the USArray Transportable Array entered the central and eastern United States, several Federal agencies (National Science Foundation, U.S. Geological Survey, U.S. Nuclear Regulatory Commission, and Department of Energy) recognized the unique opportunity to retain TA stations beyond the original timeline. The mission of the CEUSN is to produce data that enables researchers and Federal agencies alike to better understand the basic geologic questions, background earthquake rates and distribution, seismic hazard potential, and associated societal risks of this region. The selected long-term sub-array from Transportable Array (TA) stations includes nearly 200 sites, complemented by 100 broadband stations from the existing regional seismic networks to form the Central and Eastern United States Network (CEUSN). Multiple criteria for site selection were weighed by an inter-agency TA Station Selection (TASS) Working Group: seismic noise characteristics, data availability in real time, proximity to nuclear power plants, and homogeneous distribution throughout the region. The Array Network Facility (ANF) started collecting data for CEUSN network stations since late 2013, with all stations collected since May 2014. Regional seismic data streams are collected in real-time from the IRIS Data Management Center (DMC). TA stations selected to be part of CEUSN, retain the broadband sensor to which a 100 sps channel is added, the infrasound and environmental channels, and, at some stations, accelerometers are deployed. The upgraded sites become part of the N4 network for which ANF provides metadata and can issue remote commands to the station equipment. Stations still operated by TA, but planned for CEUSN, are included in the virtual network so all stations are currently available now. By the end of 2015, the remaining TA stations will be upgraded. Data quality control procedures developed for TA stations at ANF and at the DMC are currently performed on N4 data. However

  19. MyShake: A smartphone seismic network for earthquake early warning and beyond.

    PubMed

    Kong, Qingkai; Allen, Richard M; Schreier, Louis; Kwon, Young-Woo

    2016-02-01

    Large magnitude earthquakes in urban environments continue to kill and injure tens to hundreds of thousands of people, inflicting lasting societal and economic disasters. Earthquake early warning (EEW) provides seconds to minutes of warning, allowing people to move to safe zones and automated slowdown and shutdown of transit and other machinery. The handful of EEW systems operating around the world use traditional seismic and geodetic networks that exist only in a few nations. Smartphones are much more prevalent than traditional networks and contain accelerometers that can also be used to detect earthquakes. We report on the development of a new type of seismic system, MyShake, that harnesses personal/private smartphone sensors to collect data and analyze earthquakes. We show that smartphones can record magnitude 5 earthquakes at distances of 10 km or less and develop an on-phone detection capability to separate earthquakes from other everyday shakes. Our proof-of-concept system then collects earthquake data at a central site where a network detection algorithm confirms that an earthquake is under way and estimates the location and magnitude in real time. This information can then be used to issue an alert of forthcoming ground shaking. MyShake could be used to enhance EEW in regions with traditional networks and could provide the only EEW capability in regions without. In addition, the seismic waveforms recorded could be used to deliver rapid microseism maps, study impacts on buildings, and possibly image shallow earth structure and earthquake rupture kinematics. PMID:26933682

  20. MyShake: A smartphone seismic network for earthquake early warning and beyond

    PubMed Central

    Kong, Qingkai; Allen, Richard M.; Schreier, Louis; Kwon, Young-Woo

    2016-01-01

    Large magnitude earthquakes in urban environments continue to kill and injure tens to hundreds of thousands of people, inflicting lasting societal and economic disasters. Earthquake early warning (EEW) provides seconds to minutes of warning, allowing people to move to safe zones and automated slowdown and shutdown of transit and other machinery. The handful of EEW systems operating around the world use traditional seismic and geodetic networks that exist only in a few nations. Smartphones are much more prevalent than traditional networks and contain accelerometers that can also be used to detect earthquakes. We report on the development of a new type of seismic system, MyShake, that harnesses personal/private smartphone sensors to collect data and analyze earthquakes. We show that smartphones can record magnitude 5 earthquakes at distances of 10 km or less and develop an on-phone detection capability to separate earthquakes from other everyday shakes. Our proof-of-concept system then collects earthquake data at a central site where a network detection algorithm confirms that an earthquake is under way and estimates the location and magnitude in real time. This information can then be used to issue an alert of forthcoming ground shaking. MyShake could be used to enhance EEW in regions with traditional networks and could provide the only EEW capability in regions without. In addition, the seismic waveforms recorded could be used to deliver rapid microseism maps, study impacts on buildings, and possibly image shallow earth structure and earthquake rupture kinematics. PMID:26933682

  1. Array analysis methods for detection, classification and location of seismic sources: a first evaluation for aftershock analysis using dense temporary post-seismic array network

    NASA Astrophysics Data System (ADS)

    Poiata, N.; Satriano, C.; Vilotte, J.; Bernard, P.

    2012-12-01

    Detection, separation, classification and location of distributed non stationary seismic sources in broadband noisy environment is an important problem in seismology, in particular for monitoring the high-level post-seismic activity following large subduction earthquakes, like the off-shore Maule (Mw 8.8, 2010) earthquake in Central Chile. Multiple seismic arrays, and local antenna, distributed over a region allow exploiting frequency selective coherence of the signals that arrive at widely-separated array stations, leading to improved detection, convolution blind source separation, and location of distributed non stationary sources. We present here first results on the investigation of time-frequency adaptive array analysis techniques for detection and location of broadband distributed seismic events recorded by the dense temporary seismic network (International Maule Aftershock Deployment, IMAD) installed for monitoring the high-level seismic activity following the 27 February 2010 Maule earthquake (Mw 8.8). This seismic network is characterized by a large aperture, with variable inter-station distances, corroborated with a high level of distributed near and far field seismic source activity and noise. For this study, we first extract from the post-seismic network a number of seismic arrays distributed over the region covered by this network. A first aspect is devoted to passive distributed seismic sources detection, classification and separation. We investigate a number of narrow and wide band signal analysis methods both in time and time-frequency domains for energy arrival detection and tracking, including time adaptive higher order statistics, e.g. like kurtosis, and multiband band-pass filtering, together with adaptive time-frequency transformation and extraction techniques. We demonstrate that these techniques provide superior resolution and robustness than classical STA/LTA techniques in particular in the case of distributed sources with potential signal

  2. Ground Motion Simulations for Bursa Region (Turkey) Using Input Parameters derived from the Regional Seismic Network

    NASA Astrophysics Data System (ADS)

    Unal, B.; Askan, A.

    2014-12-01

    Earthquakes are among the most destructive natural disasters in Turkey and it is important to assess seismicity in different regions with the use of seismic networks. Bursa is located in Marmara Region, Northwestern Turkey and to the south of the very active North Anatolian Fault Zone. With around three million inhabitants and key industrial facilities of the country, Bursa is the fourth largest city in Turkey. Since most of the focus is on North Anatolian Fault zone, despite its significant seismicity, Bursa area has not been investigated extensively until recently. For reliable seismic hazard estimations and seismic design of structures, assessment of potential ground motions in this region is essential using both recorded and simulated data. In this study, we employ stochastic finite-fault simulation with dynamic corner frequency approach to model previous events as well to assess potential earthquakes in Bursa. To ensure simulations with reliable synthetic ground motion outputs, the input parameters must be carefully derived from regional data. In this study, using strong motion data collected at 33 stations in the region, site-specific parameters such as near-surface high frequency attenuation parameter and amplifications are obtained. Similarly, source and path parameters are adopted from previous studies that as well employ regional data. Initially, major previous events in the region are verified by comparing the records with the corresponding synthetics. Then simulations of scenario events in the region are performed. We present the results in terms of spatial distribution of peak ground motion parameters and time histories at selected locations.

  3. A study of infrasonic anisotropy and multipathing in the atmosphere using seismic networks.

    PubMed

    Hedlin, Michael A H; Walker, Kristoffer T

    2013-02-13

    We discuss the use of reverse time migration (RTM) with dense seismic networks for the detection and location of sources of atmospheric infrasound. Seismometers measure the response of the Earth's surface to infrasound through acoustic-to-seismic coupling. RTM has recently been applied to data from the USArray network to create a catalogue of infrasonic sources in the western US. Specifically, several hundred sources were detected in 2007-2008, many of which were not observed by regional infrasonic arrays. The influence of the east-west stratospheric zonal winds is clearly seen in the seismic data with most detections made downwind of the source. We study this large-scale anisotropy of infrasonic propagation, using a winter and summer source in Idaho. The bandpass-filtered (1-5 Hz) seismic waveforms reveal in detail the two-dimensional spread of the infrasonic wavefield across the Earth's surface within approximately 800 km of the source. Using three-dimensional ray tracing, we find that the stratospheric winds above 30 km altitude in the ground-to-space (G2S) atmospheric model explain well the observed anisotropy pattern. We also analyse infrasound from well-constrained explosions in northern Utah with a denser IRIS PASSCAL seismic network. The standard G2S model correctly predicts the anisotropy of the stratospheric duct, but it incorrectly predicts the dimensions of the shadow zones in the downwind direction. We show that the inclusion of finer-scale structure owing to internal gravity waves infills the shadow zones and predicts the observed time durations of the signals. From the success of this method in predicting the observations, we propose that multipathing owing to fine scale, layer-cake structure is the primary mechanism governing propagation for frequencies above approximately 1 Hz and infer that stochastic approaches incorporating internal gravity waves are a useful improvement to the standard G2S model for infrasonic propagation modelling

  4. AfricaArray: Building science capacity and improving seismic networks in Africa

    NASA Astrophysics Data System (ADS)

    Nyblade, A.; Dirks, P.; Graham, G.

    2007-05-01

    AfricaArray is a long-term initiative to promote coupled training and research programs in geophysics for building and maintaining a scientific workforce for Africa's natural resource sector. The main goals of AfricaArray are to: 1) maintain and develop further geophysical training programs in Africa, in response to industry, government and university needs, 2) promote geophysical research in Africa, and establish an Africa-to-Africa research support system, 3) obtain geophysical data, through a network of shared observatories, to study scientific targets of economic and societal interest, as well as fundamental geological processes shaping the African continent. AfricaArray is supported by a public-private partnership consisting of many government organizations in the US and Africa, and mining and oil companies. AfricaArray has been built on existing programs and expertise within partner institutions and is being implemented in three phases over ten years. During Phase 1 (1/2005 - 12/2007), the educational program at the University of the Witwatersrand is being expanded and improved to provide B.Sc., M.Sc., and Ph.D. degree training in geophysics for students from across Africa. Seismic stations are being installed or upgraded in participating countries to form a network of shared scientific observatories, and technical personnel are being trained to operate and maintain the seismic equipment. Data from the seismic stations are being used for student thesis research projects, and the seismic network is helping to catalyze scientific community building through educational and research collaborations. During subsequent phases (2007-2014), the in-situ education and research program will grow to provide B.Sc., M.Sc. and Ph.D. training for many more African students, the network of shared scientific observatories will be expanded, temporary networks of seismic stations will be installed, sustainable centers of excellence in geophysics will be established at other

  5. The new Algerian Digital Seismic Network (ADSN): towards an earthquake early-warning system

    NASA Astrophysics Data System (ADS)

    Yelles-Chaouche, A.; Allili, T.; Alili, A.; Messemen, W.; Beldjoudi, H.; Semmane, F.; Kherroubi, A.; Djellit, H.; Larbes, Y.; Haned, S.; Deramchi, A.; Amrani, A.; Chouiref, A.; Chaoui, F.; Khellaf, K.; Nait Sidi Said, C.

    2013-10-01

    Seismic monitoring in Algeria has seen great changes since the Boumerdes earthquake of 21 May 2003. Indeed, the installation of a new digital seismic network has resulted in a significant upgrade of the previous analog telemetry network. During the last four years, the number of stations in operation has increased substantially from 25 to 69, and 20 of these are broadband, 2 are very broadband, 47 are short period. 21 are equipped with accelerometers. They are all managed by Antelope software from Kinemetrics (US Cie), and they are all connected in real time and use various modes of transmission (e.g., satellite, internet, mobile phone). The spatial repartition of the stations now cover most of northern Algeria. In addition, 70 GPS stations have recently been added to this seismological network, most of them collocated with the seismological stations. Since the installation of the network, the records of local or distant events have improved significantly. The automatic processing of the data in a few minutes allows alert messages to be distributed to Civil Defense and other national authorities to react promptly to any emergency. The current strategy is to improve the data quality, to increase the density of the network by adding about 50 new stations, to reduce the processing time, and to reduce the time needed to send out an alert message. The result should be greatly improved network performance, which will lead to an effective early-warning system.

  6. Integration of a permanent OBS offshore NE Iberian Peninsula to the Catalan Seismic Network

    NASA Astrophysics Data System (ADS)

    Frontera, T.; Olivera, C.; Jara, J. A.; Goula, X.; Ugalde, A.

    2009-04-01

    On August 2005 a permanent ocean bottom seismometer (OBS) and a differential pressure gauge (DPG) were installed inside the security perimeter of the Casablanca oil platform (40 km offshore Tarragona, NE Spain), within the framework of a project which has the aim of improving the knowledge of the seismicity and seismic risk in the region. This project is being carried out by the Institut Geològic de Catalunya (IGC) and the Observatori de l'Ebre, in collaboration with the Spanish oil company Repsol Investigaciones Petrolíferas. The sensors were submerged at about 400 m to the SW of the oil platform and were deposited at about 150 m in depth. Data are digitized on-site and are transmitted through a submarine cable to the platform, where they are recorded. In July 2007 via satellite signal transmission was implemented to have continuous and real time data, which allowed integrating the OBS into the Catalan Seismic Network. Since 1999 the objectives of the Catalan Seismic Network are, on the one hand, providing rapid information for Civil Defence Services and society in general and, on the other hand, to obtain systematically high quality data for the scientific community. This real time system is based on a VSAT seismic network and it has been implemented in Catalonia (Spain) by the IGC. The project of the network was planned to create robust, high performance field infrastructures through the installation of up to 21 stations equipped with three component broad band sensors and a high dynamic range and it has been developed in several steps. In 2009, 18 stations are operative: 14 broad band and 3 accelerometers on land and one broad band OBS. The stations are based on VSAT platforms that are transmitting continuously almost real time seismic data via satellite to the IGC hub. Once at seismic data reception centre data are continuously archived and processed with an automatic system. A study of the OBS signal in terms of noise has been made and compared to the

  7. Using Seismic Signals as a Quality Assessment Tool of USArray stations at the Array Network Facility

    NASA Astrophysics Data System (ADS)

    Astiz, L.; Eakins, J. A.; Martynov, V. G.; Vernon, F. L.; Newman, R. L.; Reyes, J. C.; Cox, T. A.; Karasu, G. H.

    2009-12-01

    Full deployment of the 400 Transportable Array (TA) stations of the USArray Earthscope project was reached in September 2007. The original array footprint has rolled eastward at a rate of 200 stations per year. The Array Network Facility (ANF) is responsible for the delivery of all TA data (seismic, state of health and metadata) to the IRIS Data Management Center (DMC). In addition, the ANF provides station command and control; verification and distribution of metadata; remotely accessible world wide web interfaces for Array Operations Facility (AOF) personnel to access network and station state of health information; and quality control for all seismic data. ANF seismic analysts review individual seismic events recorded by the USArray, and to-date have produced over 2.5 million arrival picks from more than 40,000 local, regional and teleseismic events since April 2004. In the last two years, as the TA has moved away from the seismically active west coast of the United States, most of the local and regional events recorded are man-made events. The arrival picks are available in IMS format at the DMC and as compressed CSS3.0 relational databases from the ANF website. The eyes-on-data approach of these seismic signals by ANF analysts in quasi-real time allows for data quality monitoring of all deployed TA stations. This approach also allows the ANF to quickly discover problems at the stations as the network evolves given that the USArray currently records about 25 seismic events per day and that large teleseismic earthquakes (M > 6.5) are recorded at nearly all USArray stations. We use an empirical approach to compare body and surface wave recordings at a particular station with the robust stack of the nearest neighbors’ recordings to monitor continuing station performance. Using this empirical approach we will compare particle motion of P and S waves of the largest 30 shallow & deep earthquakes recorded by USArrray stations to verify sensor orientation. We will

  8. 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.

  9. Urban MEMS based seismic network for post-earthquakes rapid disaster assessment

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Antonino; Luzio, Dario; D'Anna, Giuseppe

    2014-05-01

    Life losses following disastrous earthquake depends mainly by the building vulnerability, intensity of shaking and timeliness of rescue operations. In recent decades, the increase in population and industrial density has significantly increased the exposure to earthquakes of urban areas. The potential impact of a strong earthquake on a town center can be reduced by timely and correct actions of the emergency management centers. A real time urban seismic network can drastically reduce casualties immediately following a strong earthquake, by timely providing information about the distribution of the ground shaking level. Emergency management centers, with functions in the immediate post-earthquake period, could be use this information to allocate and prioritize resources to minimize loss of human life. However, due to the high charges of the seismological instrumentation, the realization of an urban seismic network, which may allow reducing the rate of fatalities, has not been achieved. Recent technological developments in MEMS (Micro Electro-Mechanical Systems) technology could allow today the realization of a high-density urban seismic network for post-earthquakes rapid disaster assessment, suitable for the earthquake effects mitigation. In the 1990s, MEMS accelerometers revolutionized the automotive-airbag system industry and are today widely used in laptops, games controllers and mobile phones. Due to their great commercial successes, the research into and development of MEMS accelerometers are actively pursued around the world. Nowadays, the sensitivity and dynamics of these sensors are such to allow accurate recording of earthquakes with moderate to strong magnitude. Due to their low cost and small size, the MEMS accelerometers may be employed for the realization of high-density seismic networks. The MEMS accelerometers could be installed inside sensitive places (high vulnerability and exposure), such as schools, hospitals, public buildings and places of

  10. OGS improvements in the year 2011 in running the Northeastern Italy Seismic Network

    NASA Astrophysics Data System (ADS)

    Bragato, P. L.; Pesaresi, D.; Saraò, A.; Di Bartolomeo, P.; Durì, G.

    2013-04-01

    The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS (Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude Mw = 6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 12 very sensitive broad band and 21 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data centre in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of 93 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy, as shown in Fig. 1 (Bragato et al., 2011; Saraò et al., 2010). Since 2002 OGS-CRS is using the Antelope software suite as the main tool for collecting, analyzing, archiving and exchanging seismic data, initially in the framework of the EU Interreg IIIA project "Trans-national seismological networks in the South-Eastern Alps" (Bragato et al., 2010; Pesaresi et al., 2008). SeisComP is also used as a real time data exchange server tool. In order to improve the seismological monitoring of the Northeastern Italy area, at OGS-CRS we tuned existing programs and created ad hoc ones like: a customized web server named PickServer to manually relocate earthquakes, a script for automatic moment tensor determination, scripts for web publishing of earthquake parametric data, waveforms, state of health parameters and shaking maps, noise characterization by means of automatic spectra analysis, and last but not least scripts for email/SMS/fax alerting. A new OGS-CRS real time seismological website (http://rts.crs.inogs.it/) has also been operative since several years.

  11. Operational network improvements and increased reporting in the NOA (Greece) seismicity catalog.

    NASA Astrophysics Data System (ADS)

    Chouliaras, Gerasimos; Melis, Nikolaos; Drakatos, Georgios; Makropoulos, Konstantinos

    2013-04-01

    Earthquake catalogues are the basic product of seismology and of extreme importance for the assessment of seismic hazard. These data sets contain both, natural and man-made, changes. For example, seismological networks may improve their detection ability by the addition of more stations, by changing station locations for a better signal to noise condition and by improving the signal processing and analysis of seismic events. These man-made artifacts are apparent changes of the seismicity rate in earthquake catalogues and they mask the determination of real tectonic seismicity patterns. The earthquake catalog of the Institute of Geodynamics of the National Observatory of Athens (NOA) is the most detailed data set available for the Greek area containing more than 150,000 events since 1964. During this 49 year period, many changes occurred in the processing, analysis and reporting procedures, as well as changes in the configuration and infrastructure of the seismological network, however the method of the magnitude determination remained undisturbed. In February 2011 major improvements were implemented in the standard procedure for analysis and reporting at NOA and most important was the change in the method and procedure for the earthquake magnitude determination. In this investigation we will demonstrate the artificial seismicity increase in the earthquake catalog of NOA due to the recent improvements in the analysis and reporting. The results indicate a significant change in the magnitude of completeness of the earthquake catalog from a value of Mc~3 prior to 2011, to a value of Mc~2 after February 1st, 2011, mainly attributed to the registration of significantly larger number of events of smaller magnitudes. In order to maintain the homogeneity of the magnitudes reported throughout the NOA catalog, synthetic frequency-magnitude distributions are employed to determine the required conversion constants.

  12. Detection and identification of seismic signals recorded at Krakatau volcano (Indonesia) using artificial neural networks

    NASA Astrophysics Data System (ADS)

    Ibs-von Seht, M.

    2008-10-01

    The Anak Krakatau volcano (Indonesia) has been monitored by a multi-parametric system since 2005. A variety of signal types can be observed in the records of the seismic stations installed on the island volcano. These include volcano-induced signals such as LP, VT, and tremor-type events as well as signals not originating from the volcano such as regional tectonic earthquakes and transient noise signals. The work presented here aims at the realization of a system that automatically detects and identifies the signals in order to estimate and monitor current activity states of the volcano. An artificial neural network approach was chosen for the identification task. A set of parameters was defined, describing waveform and spectrogram properties of events detected by an amplitude-ratio-based (STA/LTA) algorithm. The parameters are fed into a neural network which is, after a training phase, able to generalize input data and identify corresponding event types. The success of the identification depends on the network architecture and training strategy. Several tests have been performed in order to determine appropriate network layout and training for the given problem. The performance of the final system is found to be well suited to get an overview of the seismic activity recorded at the volcano. The reliability of the network classifier, as well as general drawbacks of the methods used, are discussed.

  13. Earthquake Monitoring: SeisComp3 at the Swiss National Seismic Network

    NASA Astrophysics Data System (ADS)

    Clinton, J. F.; Diehl, T.; Cauzzi, C.; Kaestli, P.

    2011-12-01

    The Swiss Seismological Service (SED) has an ongoing responsibility to improve the seismicity monitoring capability for Switzerland. This is a crucial issue for a country with low background seismicity but where a large M6+ earthquake is expected in the next decades. With over 30 stations with spacing of ~25km, the SED operates one of the densest broadband networks in the world, which is complimented by ~ 50 realtime strong motion stations. The strong motion network is expected to grow with an additional ~80 stations over the next few years. Furthermore, the backbone of the network is complemented by broadband data from surrounding countries and temporary sub-networks for local monitoring of microseismicity (e.g. at geothermal sites). The variety of seismic monitoring responsibilities as well as the anticipated densifications of our network demands highly flexible processing software. We are transitioning all software to the SeisComP3 (SC3) framework. SC3 is a fully featured automated real-time earthquake monitoring software developed by GeoForschungZentrum Potsdam in collaboration with commercial partner, gempa GmbH. It is in its core open source, and becoming a community standard software for earthquake detection and waveform processing for regional and global networks across the globe. SC3 was originally developed for regional and global rapid monitoring of potentially tsunamagenic earthquakes. In order to fulfill the requirements of a local network recording moderate seismicity, SED has tuned configurations and added several modules. In this contribution, we present our SC3 implementation strategy, focusing on the detection and identification of seismicity on different scales. We operate several parallel processing "pipelines" to detect and locate local, regional and global seismicity. Additional pipelines with lower detection thresholds can be defined to monitor seismicity within dense subnets of the network. To be consistent with existing processing

  14. GeoNetGIS: a Geodetic Network Geographical Information System to manage GPS networks in seismic and volcanic areas

    NASA Astrophysics Data System (ADS)

    Cristofoletti, P.; Esposito, A.; Anzidei, M.

    2003-04-01

    This paper presents the methodologies and issues involved in the use of GIS techniques to manage geodetic information derived from networks in seismic and volcanic areas. Organization and manipulation of different geodetical, geological and seismic database, give us a new challenge in interpretation of information that has several dimensions, including spatial and temporal variations, also the flexibility and brand range of tools available in GeoNetGIS, make it an attractive platform for earthquake risk assessment. During the last decade the use of geodetic networks based on the Global Positioning System, devoted to geophysical applications, especially for crustal deformation monitoring in seismic and volcanic areas, increased dramatically. The large amount of data provided by these networks, combined with different and independent observations, such as epicentre distribution of recent and historical earthquakes, geological and structural data, photo interpretation of aerial and satellite images, can aid for the detection and parameterization of seismogenic sources. In particular we applied our geodetic oriented GIS to a new GPS network recently set up and surveyed in the Central Apennine region: the CA-GeoNet. GeoNetGIS is designed to analyze in three and four dimensions GPS sources and to improve crustal deformation analysis and interpretation related with tectonic structures and seismicity. It manages many database (DBMS) consisting of different classes, such as Geodesy, Topography, Seismicity, Geology, Geography and Raster Images, administrated according to Thematic Layers. GeoNetGIS represents a powerful research tool allowing to join the analysis of all data layers to integrate the different data base which aid for the identification of the activity of known faults or structures and suggesting the new evidences of active tectonics. A new approach to data integration given by GeoNetGIS capabilities, allow us to create and deliver a wide range of maps, digital

  15. Shallow Moho with aseismic upper crust and deep Moho with seismic lower crust beneath the Japanese Islands obtained by seismic tomography using data from dense seismic network

    NASA Astrophysics Data System (ADS)

    Matsubara, Makoto; Obara, Kazushige

    2015-04-01

    P-wave seismic velocity is well known to be up to 7.0 km/s and over 7.5 km/s in the lower crust and in the mantle, respectively. A large velocity gradient is the definition of the Moho discontinuity between the crust and mantle. In this paper, we investigates the configuration of Moho discontinuity defined as an isovelocity plane with large velocity gradient derived from our fine-scale three-dimensional seismic velocity structure beneath Japanese Islands using data obtained by dense seismic network with the tomographic method (Matsubara and Obara, 2011). Japanese Islands are mainly on the Eurasian and North American plates. The Philippine Sea and Pacific plates are subducting beneath these continental plates. We focus on the Moho discontinuity at the continental side. We calculate the P-wave velocity gradients between the vertical grid nodes since the grid inversion as our tomographic method does not produce velocity discontinuity. The largest velocity gradient is 0.078 (km/s)/km at velocities of 7.2 and 7.3 km/s. We define the iso-velocity plane of 7.2 km/s as the Moho discontinuity. We discuss the Moho discontinuity above the upper boundary of the subducting oceanic plates with consideration of configuration of plate boundaries of prior studies (Shiomi et al., 2008; Kita et al., 2010; Hirata et al, 2012) since the Moho depth derived from the iso-velocity plane denotes the oceanic Moho at the contact zones of the overriding continental plates and the subducting oceanic plates. The Moho discontinuity shallower than 30 km depth is distributed within the tension region like northern Kyushu and coastal line of the Pacific Ocean in the northeastern Japan and the tension region at the Cretaceous as the northeastern Kanto district. These regions have low seismicity within the upper crust. Positive Bouguer anomaly beneath the northeastern Kanto district indicates the ductile material with large density in lower crust at the shallower portion and the aseismic upper crust

  16. Sismos a l'Ecole : a Seismic Educational Network (FRANCE) linked with Research

    NASA Astrophysics Data System (ADS)

    Berenguer, J.; Le Puth, J.; Courboulex, F.; Zodmi, B.; Boneff, M.

    2007-12-01

    Ahead of the quick evolution of our society, in which scientific information has to be accurately understood by a great majority, the promotion of a responsible behaviour coming from educated and trained citizens has become a priority. One of the roles of school is to enable children to understand sciences, these same sciences that were long ago the prerogative of scientific laboratories. The educational network SISMOS à l\\'"Ecole is an example of a project structured on the knowledge of seismic risks through a scientific and technological approach. It develops a teaching method leading to an approach towards the knowledge of natural disasters. The original and innovating feature of this educational network is to enable students to set up a seismograph in their school. The recorded signals - coming from a regional or a worldwide seismic activity - feed an on- line database, which is in fact a real research centre for seismic resources as well as a starting point for educational and scientific activities. The network, that numbers about thirty stations set up in France, in its overseas departments and territories, and in a couple of French schools abroad, is based upon an experience initiated in the French Riviera ten years ago or so. The achievement of the program has from then on gone beyond the simple purpose of conveying seismic data that research and monitoring centres could have recorded. Thanks to the use of scientific measures, students become involved and get into complex notions revolving around geophysics and geosciences. Developing simple tools, setting up concrete experiments combined with an investigate reasoning makes it easier to build up a quality scientific culture as well as an education of citizens to risks.

  17. OGS improvements in the year 2011 in running the Northeastern Italy Seismic Network

    NASA Astrophysics Data System (ADS)

    Bragato, P. L.; Pesaresi, D.; Saraò, A.; Di Bartolomeo, P.; Durı, G.

    2012-04-01

    The Centro di Ricerche Sismologiche (CRS, Seismological Research Center) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 15 very sensitive broad band and 21 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS-CRS data center in Udine. Real time data exchange agreements in place with other Italian, Slovenian, Austrian and Swiss seismological institutes lead to a total number of about 100 seismic stations acquired in real time, which makes the OGS the reference institute for seismic monitoring of Northeastern Italy. Since 2002 OGS-CRS is using the Antelope software suite on several workstations plus a SUN Cluster as the main tool for collecting, analyzing, archiving and exchanging seismic data, initially in the framework of the EU Interreg IIIA project "Trans-national seismological networks in the South-Eastern Alps". SeisComP is also used as a real time data exchange server tool. In order to improve the seismological monitoring of the Northeastern Italy area, at OGS-CRS we tuned existing programs and created ad hoc ones like: a customized web server named PickServer to manually relocate earthquakes, a script for automatic moment tensor determination, scripts for web publishing of earthquake parametric data, waveforms, state of health parameters and shaking maps, noise characterization by means of automatic spectra analysis, and last but not least scripts for email/SMS/fax alerting. The OGS-CRS Real Time Seismological website (RTS, http://rts.crs.inogs.it/) operative since several years was initially developed in the framework of the Italian DPC-INGV S3 Project: the RTS website shows classic earthquake locations

  18. The RING and Seismic Network: Data Acquisition of Co-located Stations

    NASA Astrophysics Data System (ADS)

    Falco, L.; Avallone, A.; Cattaneo, M.; Cecere, G.; Cogliano, R.; D'Agostino, N.; D'Ambrosio, C.; D'Anastasio, E.; Selvaggi, G.

    2007-12-01

    The plate boundary between Africa and Eurasia represents an interesting geodynamical region characterized by a complex pattern of deformation. First-order scientific problems regarding the existence of rigid blocks within the plate boundary, the present-day activity of the Calabrian subduction zone and the modes of release of seismic deformation are still awaiting for a better understanding. To address these issues, the INGV (Istituto Nazionale Geofisica e Vulcanlogia) deployed a permanent, integrated and real-time monitoring GPS network (RING) all over Italy. RING is now constituted by about 120 stations. The CGPS sites, acquiring at 1Hz and 30s sampling rate, are integrated either with broad band or very broad band seismometers and accelerometers for an improved definition of the seismically active regions. Most of the sites are connected to the acquisition centre (located in Rome and duplicated in Grottaminarda) through a satellite system (VSAT), while the remaining sites transmit data by Internet and classical phone connections. The satellite data transmission and the integration with seismic instruments makes this network one of the most innovative CGPS networks in Europe. The heterogeneity of the installed instrumentation, the transmission types and the increasing number of stations needed a central monitoring and acquisition system. A central acquisition system has been developed in Grottaminarda in southern Italy. Regarding the seismic monitoring we chose to use the open source system Earthworm, developed by USGS, with which we store waveforms and implement automatic localization of the seismic events occurring in the area. As most of the GPS sites are acquired by means of Nanometrics satellite technology, we developed a specific software (GpsView), written in Java, to monitor the state of health of those CGPS. This software receives GPS data from NaqsServer (Nanometrics acquisition system) and outputs information about the sites (i.e. approx position

  19. The Armutlu Network - a contribution to seismic hazard assessment in the Marmara region

    NASA Astrophysics Data System (ADS)

    Lühr, B.-G.; Bariş, Ş.; Grosser, H.; Irmak, T. S.; Woith, H.; Donner, S.; Özer, M. F.; Çaka, D.; Zschau, J.

    2009-04-01

    The North Anatolian Fault Zone (NAFZ) represents one of the most prominent continental transforms and slips at an average rate of 20-30 mm/yr. During the 20th century, the NAFZ has ruptured over about 900 km of its more than 1,500 km length by ten devastating earthquakes with magnitudes above Ms > 6.5. Today, a segment inside the Marmara Sea just south of the megacity of Istanbul represents a seismic gap that is believed being capable of generating a M ≥7 earthquake within the next decades. East of this segment the western end of the 1999 Kocaeli earthquake rupture is located next to the northern shoreline of the Armutlu Peninsula depicted by distinct clusters of micro-seismic activity. As a contribution to hazard assessment the local seismic network ARMNET had been set-up in 2005 in co-operation between Kocaeli University, and GFZ, to monitor the chronological evolution of seismicity, and to investigate the deformation of the Armutlu Peninsula, as well as possible interactions between seismic waves and pore-pressure variations in geothermal systems. The installation was strongly supported by local governments, and lead to a strong interest and an increasing knowledge transfer to local authorities. The ARMNET contributes to the implementation of an Anatolian plate boundary observatory (PBO) belonging to a series of GFZ-operated Earth System Observatories to systemically study coupled Earth processes, and is imbedded in the framework of the CEDIM (CEnter for DIsaster Management and Risk Reduction Technology) project "Megacity Istanbul", which involves the analysis of the seismicity of the Greater Istanbul region. At present, ARMNET consist of 12 short period and 10 broadband stations. Additionally, a borehole seismometer has been installed in a 100 m borehole close to Yalova. Most of the detected events occurred in a depth range of 5 to 15 km, and determined duration magnitudes are in a range 0.4 and 5.3 with a magnitude of completeness of 1.3. Besides seismic

  20. Shallow Moho with aseismic upper crust and deep Moho with seismic lower crust beneath the Japanese Islands obtained by seismic tomography using data from dense seismic network

    NASA Astrophysics Data System (ADS)

    Matsubara, Makoto; Obara, Kazushige

    2015-04-01

    P-wave seismic velocity is well known to be up to 7.0 km/s and over 7.5 km/s in the lower crust and in the mantle, respectively. A large velocity gradient is the definition of the Moho discontinuity between the crust and mantle. In this paper, we investigates the configuration of Moho discontinuity defined as an isovelocity plane with large velocity gradient derived from our fine-scale three-dimensional seismic velocity structure beneath Japanese Islands using data obtained by dense seismic network with the tomographic method (Matsubara and Obara, 2011). Japanese Islands are mainly on the Eurasian and North American plates. The Philippine Sea and Pacific plates are subducting beneath these continental plates. We focus on the Moho discontinuity at the continental side. We calculate the P-wave velocity gradients between the vertical grid nodes since the grid inversion as our tomographic method does not produce velocity discontinuity. The largest velocity gradient is 0.078 (km/s)/km at velocities of 7.2 and 7.3 km/s. We define the iso-velocity plane of 7.2 km/s as the Moho discontinuity. We discuss the Moho discontinuity above the upper boundary of the subducting oceanic plates with consideration of configuration of plate boundaries of prior studies (Shiomi et al., 2008; Kita et al., 2010; Hirata et al, 2012) since the Moho depth derived from the iso-velocity plane denotes the oceanic Moho at the contact zones of the overriding continental plates and the subducting oceanic plates. The Moho discontinuity shallower than 30 km depth is distributed within the tension region like northern Kyushu and coastal line of the Pacific Ocean in the northeastern Japan and the tension region at the Cretaceous as the northeastern Kanto district. These regions have low seismicity within the upper crust. Positive Bouguer anomaly beneath the northeastern Kanto district indicates the ductile material with large density in lower crust at the shallower portion and the aseismic upper crust

  1. A seismic network to investigate the sedimentary hosted hydrothermal Lusi system

    NASA Astrophysics Data System (ADS)

    Javad Fallahi, Mohammad; Mazzini, Adriano; Lupi, Matteo; Obermann, Anne; Karyono, Karyono

    2016-04-01

    The 29th of May 2006 marked the beginning of the sedimentary hosted hydrothermal Lusi system. During the last 10 years we witnessed numerous alterations of the Lusi system behavior that coincide with the frequent seismic and volcanic activity occurring in the region. In order to monitor the effect that the seismicity and the activity of the volcanic arc have on Lusi, we deployed a ad hoc seismic network. This temporary network consist of 10 broadband and 21 short period stations and is currently operating around the Arjuno-Welirang volcanic complex, along the Watukosek fault system and around Lusi, in the East Java basin since January 2015. We exploit this dataset to investigate surface wave and shear wave velocity structure of the upper-crust beneath the Arjuno-Welirang-Lusi complex in the framework of the Lusi Lab project (ERC grant n° 308126). Rayleigh and Love waves travelling between each station-pair are extracted by cross-correlating long time series of ambient noise data recorded at the stations. Group and phase velocity dispersion curves are obtained by time-frequency analysis of cross-correlation functions, and are tomographically inverted to provide 2D velocity maps corresponding to different sampling depths. 3D shear wave velocity structure is then acquired by inverting the group velocity maps.

  2. Operation of a telemetered seismic network on the Alaska Peninsula. Annual report

    SciTech Connect

    Not Available

    1981-02-01

    A large aperture network of eleven short period seismic stations is being operated on the Alaska Peninsula and several offshore islands to acquire data for the study of the seismotectonics of a part of the Alaska-Aleutian arc-trench structure. The system operated satisfactorily during the past year and continued to provide seismic coverage at a low magnitude threshold level (M/sub L/ = 2.0). An event detection system, developed under this contract over the past years, has been field installed and is undergoing fine tuning. Focal mechanism studies of intermediate depths Benioff zone earthquakes were continued. Like a previous, smaller set, these mechanisms show predominantly down-dip extension, indicating gravitational sinking of the subducting lithosphere. Analysis of the combined data from our network and a temporary array of Ocean Bottom Seismometers, deployed under a related study, indicate that epicenters of earthquakes in the continental shelf area off Kodiak Island are shifted landward by about 15 km with respect to the epicenters determined from the combined data set. Clusters of shallow seismic activity associated with certain Alaska Peninsula volcanoes, observed over the past years, had previously been interpreted as related to shallow magmatic-geothermal reservoirs. Volcanologic-petrologic field studies conducted last year show that volcanic centers associated with such swarms do indeed have surface manifestations of hydrothermal activity.

  3. Modeling propagation of infrasound signals observed by a dense seismic network.

    PubMed

    Chunchuzov, I; Kulichkov, S; Popov, O; Hedlin, M

    2014-01-01

    The long-range propagation of infrasound from a surface explosion with an explosive yield of about 17.6 t TNT that occurred on June 16, 2008 at the Utah Test and Training Range (UTTR) in the western United States is simulated using an atmospheric model that includes fine-scale layered structure of the wind velocity and temperature fields. Synthetic signal parameters (waveforms, amplitudes, and travel times) are calculated using parabolic equation and ray-tracing methods for a number of ranges between 100 and 800 km from the source. The simulation shows the evolution of several branches of stratospheric and thermospheric signals with increasing range from the source. Infrasound signals calculated using a G2S (ground-to-space) atmospheric model perturbed by small-scale layered wind velocity and temperature fluctuations are shown to agree well with recordings made by the dense High Lava Plains seismic network located at an azimuth of 300° from UTTR. The waveforms of calculated infrasound arrivals are compared with those of seismic recordings. This study illustrates the utility of dense seismic networks for mapping an infrasound field with high spatial resolution. The parabolic equation calculations capture both the effect of scattering of infrasound into geometric acoustic shadow zones and significant temporal broadening of the arrivals. PMID:24437743

  4. Neural network accuracy measures and data transforms applied to the seismic parameter estimation problem

    SciTech Connect

    Glover, C.W.; Barhen, J.; Aminzadeh, F.; Toomarian, N.B.

    1997-01-01

    The accuracy of an artificial neural network (ANN) algorithm is a crucial issue in the estimation of an oil field reservoir`s properties from remotely sensed seismic data. This paper demonstrates the use of the k-fold cross validation technique to obtain confidence bounds on an ANN`s accuracy statistic from a finite sample set. In addition, we also show that an ANN`s classification accuracy is dramatically improved by transforming the ANN`s input feature space to a dimensionally smaller, new input space. The new input space represents a feature space that maximizes the linear separation between classes. Thus, the ANN`s convergence time and accuracy are improved because the ANN must merely find nonlinear perturbations to the starting linear decision boundaries. These techniques for estimating ANN accuracy bounds and feature space transformations are demonstrated on the problem of estimating the sand thickness in an oil field reservoir based only on remotely sensed seismic data.

  5. A Multi-Step Assessment Scheme for Seismic Network Site Selection in Densely Populated Areas

    NASA Astrophysics Data System (ADS)

    Plenkers, Katrin; Husen, Stephan; Kraft, Toni

    2015-10-01

    We developed a multi-step assessment scheme for improved site selection during seismic network installation in densely populated areas. Site selection is a complex process where different aspects (seismic background noise, geology, and financing) have to be taken into account. In order to improve this process, we developed a step-wise approach that allows quantifying the quality of a site by using, in addition to expert judgement and test measurements, two weighting functions as well as reference stations. Our approach ensures that the recording quality aimed for is reached and makes different sites quantitatively comparable to each other. Last but not least, it is an easy way to document the decision process, because all relevant parameters are listed, quantified, and weighted.

  6. Station corrections for the Katmai Region Seismic Network

    USGS Publications Warehouse

    Searcy, Cheryl K.

    2003-01-01

    Most procedures for routinely locating earthquake hypocenters within a local network are constrained to using laterally homogeneous velocity models to represent the Earth's crustal velocity structure. As a result, earthquake location errors may arise due to actual lateral variations in the Earth's velocity structure. Station corrections can be used to compensate for heterogeneous velocity structure near individual stations (Douglas, 1967; Pujol, 1988). The HYPOELLIPSE program (Lahr, 1999) used by the Alaska Volcano Observatory (AVO) to locate earthquakes in Cook Inlet and the Aleutian Islands is a robust and efficient program that uses one-dimensional velocity models to determine hypocenters of local and regional earthquakes. This program does have the capability of utilizing station corrections within it's earthquake location proceedure. The velocity structures of Cook Inlet and Aleutian volcanoes very likely contain laterally varying heterogeneities. For this reason, the accuracy of earthquake locations in these areas will benefit from the determination and addition of station corrections. In this study, I determine corrections for each station in the Katmai region. The Katmai region is defined to lie between latitudes 57.5 degrees North and 59.00 degrees north and longitudes -154.00 and -156.00 (see Figure 1) and includes Mount Katmai, Novarupta, Mount Martin, Mount Mageik, Snowy Mountain, Mount Trident, and Mount Griggs volcanoes. Station corrections were determined using the computer program VELEST (Kissling, 1994). VELEST inverts arrival time data for one-dimensional velocity models and station corrections using a joint hypocenter determination technique. VELEST can also be used to locate single events.

  7. Monitoring of seismic time-series with advanced parallel computational tools and complex networks

    NASA Astrophysics Data System (ADS)

    Kechaidou, M.; Sirakoulis, G. Ch.; Scordilis, E. M.

    2012-04-01

    Earthquakes have been in the focus of human and research interest for several centuries due to their catastrophic effect to the everyday life as they occur almost all over the world demonstrating a hard to be modelled unpredictable behaviour. On the other hand, their monitoring with more or less technological updated instruments has been almost continuous and thanks to this fact several mathematical models have been presented and proposed so far to describe possible connections and patterns found in the resulting seismological time-series. Especially, in Greece, one of the most seismically active territories on earth, detailed instrumental seismological data are available from the beginning of the past century providing the researchers with valuable and differential knowledge about the seismicity levels all over the country. Considering available powerful parallel computational tools, such as Cellular Automata, these data can be further successfully analysed and, most important, modelled to provide possible connections between different parameters of the under study seismic time-series. More specifically, Cellular Automata have been proven very effective to compose and model nonlinear complex systems resulting in the advancement of several corresponding models as possible analogues of earthquake fault dynamics. In this work preliminary results of modelling of the seismic time-series with the help of Cellular Automata so as to compose and develop the corresponding complex networks are presented. The proposed methodology will be able to reveal under condition hidden relations as found in the examined time-series and to distinguish the intrinsic time-series characteristics in an effort to transform the examined time-series to complex networks and graphically represent their evolvement in the time-space. Consequently, based on the presented results, the proposed model will eventually serve as a possible efficient flexible computational tool to provide a generic

  8. Predicting the performance of local seismic networks using Matlab and Google Earth.

    SciTech Connect

    Chael, Eric Paul

    2009-11-01

    We have used Matlab and Google Earth to construct a prototype application for modeling the performance of local seismic networks for monitoring small, contained explosions. Published equations based on refraction experiments provide estimates of peak ground velocities as a function of event distance and charge weight. Matlab routines implement these relations to calculate the amplitudes across a network of stations from sources distributed over a geographic grid. The amplitudes are then compared to ambient noise levels at the stations, and scaled to determine the smallest yield that could be detected at each source location by a specified minimum number of stations. We use Google Earth as the primary user interface, both for positioning the stations of a hypothetical local network, and for displaying the resulting detection threshold contours.

  9. 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.

  10. The North East Italy (NI) broadband seismic network run by OGS: experience in improving the long period performances

    NASA Astrophysics Data System (ADS)

    Pesaresi, D.

    2009-04-01

    The NI broadband seismic network is designed to monitor regional seismic activity of North East Italy and surroundings as well as to provide high quality data for various research projects in regional and global broadband seismology, like moment tensor determination. The network, grown during the last 30 years within local Civil Defence agencies and neighbouring scientific institutions cooperation, currently consists of 11 digital broadband stations equipped with Streckeisen STS-2 and STS-1, Nanometrics Trillium 40 and Guralp CMG-3T seismometers with 120 and 40 seconds long period corners; most of the seismic stations are also equipped with accelerometers. Waveforms and parametric data of the NI seismic network are transmitted in real time to the Friuli-Venezia Giulia,Veneto and Provincia di Trento Civil Defence Agencies, to the Italian National Institute for Geophysics and Volcanology (INGV) and to the Earth Science Department (DST) of the Trieste University in Italy, to the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) in Vienna, Austria and to the Environmental Agency of the Republic of Slovenia (ARSO) in Ljubljana, Slovenia to support emergency management and seismological studies in the whole Alps-Dinarides junction zone. The commercial Antelope software suite from BRTT has been chosen as the common basis for real time data exchange, rapid location of earthquakes and alerting. In order to guarantee high quality installations, we sustain a continuous effort that involves searches for appropriate sites, away from sources of long period noise, improvements in installation procedures and insulation techniques, maintenance of transfer function files and routine monitoring of noise conditions at individual existing station. The quality of the seismic data is checked through the noise Power Spectral Density (PSD) analysis. The insulation equipment that we designed for our network is a local adaptation of the pressure-thermal insulation

  11. The AlpArray Seismic Network: current status and next steps

    NASA Astrophysics Data System (ADS)

    Hetényi, György; Molinari, Irene; Clinton, John; Kissling, Edi

    2016-04-01

    The AlpArray initiative (http://www.alparray.ethz.ch) is a large-scale European collaboration to study the entire Alpine orogen at high resolution and in 3D with a large variety of geoscientific methods. The core element of the initiative is an extensive and dense broadband seismological network, the AlpArray Seismic Network (AASN), which complements the permanent seismological stations to ensure homogeneous coverage of the greater Alpine area. The some 260 temporary stations of the AlpArray Seismic Network are operated as a joint effort by a number of institutions from Austria, Bosnia-Herzegovina, Croatia, Czech Republic, France, Germany, Hungary, Italy, Slovakia and Switzerland. The first stations were installed in Spring 2015 and the full AASN is planned to be operational by early Summer 2016. In this poster we present the actual status of the deployment, the effort undertaken by the contributing groups, station performance, typical noise levels, best practices in installation as well as in data management, often encountered challenges, and planned next steps including the deployment of ocean bottom seismometers in the Ligurian Sea.

  12. Application of back-propagation neural networks to identification of seismic arrival types

    NASA Astrophysics Data System (ADS)

    Dai, Hengchang; MacBeth, Colin

    1997-05-01

    A back-propagation neural network (BPNN) approach is developed to identify P- and S-arrivals from three-component recordings of local earthquake data. The BPNN is trained by selecting trace segments of P- and S-waves and noise bursts converted into an attribute space based on the degree of polarization (DOP). After training, the network can automatically identify the type of arrival on earthquake recordings. Compared with manual analysis, a BPNN trained with nine groups of DOP segments can correctly identify 82.3% of the P-arrivals and 62.6% of the S-arrivals from one seismic station, and when trained with five groups from a training dataset selected from another seismic station, it can correctly identify 76.6% of the P-arrivals and 60.5% of S-arrivals. This approach is adaptive and needs only the onset time of arrivals as input, although its performance cannot be improved by simply adding more training datasets due to the complexity of DOP patterns. Our experience suggests that other information or another network may be necessary to improve its performance.

  13. Crowd-Sourcing Seismic Data: Lessons Learned from the Quake-Catcher Network

    NASA Astrophysics Data System (ADS)

    Cochran, E. S.; Sumy, D. F.; DeGroot, R. M.; Clayton, R. W.

    2015-12-01

    The Quake Catcher Network (QCN; qcn.caltech.edu) uses low cost micro-electro-mechanical system (MEMS) sensors hosted by volunteers to collect seismic data. Volunteers use accelerometers internal to laptop computers, phones, tablets or small (the size of a matchbox) MEMS sensors plugged into desktop computers using a USB connector to collect scientifically useful data. Data are collected and sent to a central server using the Berkeley Open Infrastructure for Network Computing (BOINC) distributed computing software. Since 2008, when the first citizen scientists joined the QCN project, sensors installed in museums, schools, offices, and residences have collected thousands of earthquake records. We present and describe the rapid installations of very dense sensor networks that have been undertaken following several large earthquakes including the 2010 M8.8 Maule Chile, the 2010 M7.1 Darfield, New Zealand, and the 2015 M7.8 Gorkha, Nepal earthquake. These large data sets allowed seismologists to develop new rapid earthquake detection capabilities and closely examine source, path, and site properties that impact ground shaking at a site. We show how QCN has engaged a wide sector of the public in scientific data collection, providing the public with insights into how seismic data are collected and used. Furthermore, we describe how students use data recorded by QCN sensors installed in their classrooms to explore and investigate earthquakes that they felt, as part of 'teachable moment' exercises.

  14. Study of IDC infrasound REB solutions using Egyptian National Seismic Network data

    NASA Astrophysics Data System (ADS)

    Ali, Sherif M.; Polich, Paul

    2015-04-01

    Infrasound is one of three waveform technologies which are part of the Comprehensive Nuclear Test Ban Treaty (CTBT) verification regime. The International Monitoring System (IMS) of the CTBT consists of 337 monitoring stations and laboratories world-wide. These facilities include 45 infrasound stations, installed world-wide and transmitting data to the International Data Centre (IDC). Since early 2010, the IDC began routine automatic and interactive processing of infrasound data; the detected and located events are systematically included in the Reviewed Event Bulletin (REB). Infrasound events are frequently characterized by a small number of infrasound phase associations. This poses a challenge to obtaining high-confidence event solutions during routine processing of infrasound data. This study focuses on six infragenic events from the REB, occurring between January 2011 and December 2014, which were thoroughly analyzed at the IDC. The selected events were characteristically seismo-acoustic, and corroborated by seismic recordings of the Egyptian National Seismic Network (ENSN) operated by the National Research Institute of Astronomy and Geophysics (NRIAG). Utilizing this additional local network data of ENSN enables sharper assessment of the IDC published event solutions. Notably, the events were recorded within Egypt and regional surroundings where infrasound waves were generated. The events were detected by IMS infrasound stations located up to 7000 kilometers away. Additional analyses, beyond the six infragenic events from the REB, will also consider some valid infragenic events that fall short of stringent REB Event Definition Criteria. The events will primarily consist of two defining stations with lower-confidence event solutions. The selected events, when confirmed by the seismic observations at ENSN, provide a unique dataset for evaluating IDC infrasound event solutions. Further objectives of the study seek to measure the performance of the IMS network for

  15. 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.

  16. Seismic Velocities Imaging around "AFA" Hydrothermal Area in West Java, Indonesia derived from Dense Seimometer Network

    NASA Astrophysics Data System (ADS)

    Fanani Akbar, Akhmad; Nugraha, Andri Dian; Jousset, Philippe GM; Ryannugroho, Riskiray; Gassner, Alexandra; Jaya, Makky S.; Sule, Rachmat; Diningrat, Wahyuddin; Hendryana, Andri; Kusnadi, Yosep; Umar, Muksin; Indrinanto, Yudi; Erbas, Kemal

    2015-04-01

    We have deployed about 48 three component seismometers around "AFA" hydrothermal are in West Java, Indonesia from October 2012 up to October 2014 in order to detect microseismic event and to enhance our knowledge about subsurface seismic stucture. The seismometer network in this study, is the first dense seismometer array monitoring around hydrothermal area in Indonesia so far. We analyzed a huge waveform data set to distinguish microseismic, local and regional events. Then, we picked the onset of P-and S-wave arrival of microseismic events carefully visually by eye. We determined the initial microseismic event by applying Geiger's method with uniform seismic velocity model. Totally, we have been successfully determined 2,497 microseismic events around this hydrothermal area. We also improved 1D seismic velocities (Vp, Vs) and simultaneously with hypocenter adjustment as input for the tomography inversion in this study. Overall, the microseismic events are concentrated around production area activities and we also found strong cluster microseismic event in Southern part of this region which still need to be investigated in more details. Now, we are going on tomographic inversion step by using double-difference method. We are going to show more information during the meeting.

  17. Explosion Source Location Study Using Collocated Acoustic and Seismic Networks in Israel

    NASA Astrophysics Data System (ADS)

    Pinsky, V.; Gitterman, Y.; Arrowsmith, S.; Ben-Horin, Y.

    2013-12-01

    We explore a joined analysis of seismic and infrasonic signals for improvement in automatic monitoring of small local/regional events, such as construction and quarry blasts, military chemical explosions, sonic booms, etc. using collocated seismic and infrasonic networks recently build in Israel (ISIN) in the frame of the project sponsored by the Bi-national USA-Israel Science Foundation (BSF). The general target is to create an automatic system, which will provide detection, location and identification of explosions in real-time or close-to-real time manner. At the moment the network comprises 15 stations hosting a microphone and seismometer (or accelerometer), operated by the Geophysical Institute of Israel (GII), plus two infrasonic arrays, operated by the National Data Center, Soreq: IOB in the South (Negev desert) and IMA in the North of Israel (Upper Galilee),collocated with the IMS seismic array MMAI. The study utilizes a ground-truth data-base of numerous Rotem phosphate quarry blasts, a number of controlled explosions for demolition of outdated ammunitions and experimental surface explosions for a structure protection research, at the Sayarim Military Range. A special event, comprising four military explosions in a neighboring country, that provided both strong seismic (up to 400 km) and infrasound waves (up to 300 km), is also analyzed. For all of these events the ground-truth coordinates and/or the results of seismic location by the Israel Seismic Network (ISN) have been provided. For automatic event detection and phase picking we tested the new recursive picker, based on Statistically optimal detector. The results were compared to the manual picks. Several location techniques have been tested using the ground-truth event recordings and the preliminary results obtained have been compared to the ground-truth locations: 1) a number of events have been located as intersection of azimuths estimated using the wide-band F-K analysis technique applied to the

  18. RMT focal plane sensitivity to seismic network geometry and faulting style

    NASA Astrophysics Data System (ADS)

    Johnson, Kendra L.; Hayes, Gavin P.; Herrmann, Robert B.; Benz, Harley M.; McNamara, Dan E.; Bergman, Eric

    2016-04-01

    Modern tectonic studies often use regional moment tensors (RMTs) to interpret the seismotectonic framework of an earthquake or earthquake sequence; however, despite extensive use, little existing work addresses RMT parameter uncertainty. Here, we quantify how network geometry and faulting style affect RMT sensitivity. We examine how data-model fits change with fault plane geometry (strike and dip) for varying station configurations. We calculate the relative data fit for incrementally varying geometries about a best-fit solution, applying our workflow to real and synthetic seismograms for both real and hypothetical station distributions and earthquakes. Initially, we conduct purely observational tests, computing RMTs from synthetic seismograms for hypothetical earthquakes and a series of well-behaved network geometries. We then incorporate real data and station distributions from the International Maule Aftershock Deployment (IMAD), which recorded aftershocks of the 2010 MW 8.8 Maule earthquake, and a set of regional stations capturing the ongoing earthquake sequence in Oklahoma and southern Kansas. We consider RMTs computed under three scenarios: (1) real seismic records selected for high data quality; (2) synthetic seismic records with noise computed for the observed source-station pairings; and (3) synthetic seismic records with noise computed for all possible station-source pairings. To assess RMT sensitivity for each test, we observe the "fit falloff", which portrays how relative fit changes when strike or dip varies incrementally; we then derive the ranges of acceptable strikes and dips by identifying the span of solutions with relative fits larger than 90% of the best-fit. For the azimuthally incomplete IMAD network, Scenario 3 best constrains fault geometry, with average ranges of 45° and 31° for strike and dip, respectively. In Oklahoma, Scenario 3 best constrains fault dip with an average range of 46°; however, strike is best constrained by Scenario 1

  19. Earthquakes in the Classroom, Las Vegas, NV: The Nevada Educational Seismic Network (NESN)

    NASA Astrophysics Data System (ADS)

    Hopkins, J.; Snelson, C. M.; Zaragoza, S. A.; Smith, K.; Depolo, D.

    2002-12-01

    Geophysics is a term guaranteed to strike fear into the heart of the bravest high school science student. Using math to describe the earth can involve complex equations that can only be deciphered by enigmatic computer programs. But high school science students in the Las Vegas Valley have been given a unique opportunity to gather important research information while learning about geophysics, real-time data collection, and Internet communications in a less threatening environment. Three seismograph stations funded by the Department of Energy and the University of Nevada, Las Vegas have been installed in three different high schools in the Clark County School District. These three stations form a triangle in the Las Vegas Valley basin covering areas where the basin depths change significantly. The geophones are buried outside and a cable connects the sensors and GPS receiver to a digitizer on a local PC. The data is transmitted continuously in real-time via Internet communications protocols to the Seismic Explorer Monitoring Network. There it is available to all schools and to researchers who will analyze the data. These short-period geophones will record small local earthquakes and larger more distant events contributing to real-time seismic network operations in southern Nevada. Students at a school site are able to see live real-time data from other school stations as well as from seismograph stations in southern Nevada, the western US, and the world. Mentored by researchers at the University of Nevada, Reno and University of Nevada, Las Vegas, the teachers and students conduct simple waveform analysis to determine earthquake locations and magnitudes and operate the stations in this cooperative research effort. The goal of this partnership between secondary and university educational systems is to create a successful alliance that will benefit the research community as well as the classroom teacher and his/her students. Researchers will use the data collected

  20. RMT focal plane sensitivity to seismic network geometry and faulting style

    NASA Astrophysics Data System (ADS)

    Johnson, Kendra L.; Hayes, Gavin P.; Herrmann, Robert B.; Benz, Harley M.; McNamara, Dan E.; Bergman, Eric

    2016-07-01

    Modern tectonic studies often use regional moment tensors (RMTs) to interpret the seismotectonic framework of an earthquake or earthquake sequence; however, despite extensive use, little existing work addresses RMT parameter uncertainty. Here, we quantify how network geometry and faulting style affect RMT sensitivity. We examine how data-model fits change with fault plane geometry (strike and dip) for varying station configurations. We calculate the relative data fit for incrementally varying geometries about a best-fitting solution, applying our workflow to real and synthetic seismograms for both real and hypothetical station distributions and earthquakes. Initially, we conduct purely observational tests, computing RMTs from synthetic seismograms for hypothetical earthquakes and a series of well-behaved network geometries. We then incorporate real data and station distributions from the International Maule Aftershock Deployment (IMAD), which recorded aftershocks of the 2010 MW 8.8 Maule earthquake, and a set of regional stations capturing the ongoing earthquake sequence in Oklahoma and southern Kansas. We consider RMTs computed under three scenarios: (1) real seismic records selected for high data quality; (2) synthetic seismic records with noise computed for the observed source-station pairings and (3) synthetic seismic records with noise computed for all possible station-source pairings. To assess RMT sensitivity for each test, we observe the `fit falloff', which portrays how relative fit changes when strike or dip varies incrementally; we then derive the ranges of acceptable strikes and dips by identifying the span of solutions with relative fits larger than 90 per cent of the best fit. For the azimuthally incomplete IMAD network, Scenario 3 best constrains fault geometry, with average ranges of 45° and 31° for strike and dip, respectively. In Oklahoma, Scenario 3 best constrains fault dip with an average range of 46°; however, strike is best constrained by

  1. Toward the azimuthal characteristics of ionospheric and seismic effects of "Chelyabinsk" meteorite fall according to the data from coherent radar, GPS, and seismic networks

    NASA Astrophysics Data System (ADS)

    Berngardt, O. I.; Perevalova, N. P.; Dobrynina, A. A.; Kutelev, K. A.; Shestakov, N. V.; Bakhtiarov, V. F.; Kusonsky, O. A.; Zagretdinov, R. V.; Zherebtsov, G. A.

    2015-12-01

    We present the results of a study of the azimuthal characteristics of ionospheric and seismic effects of the meteorite `Chelyabinsk,' based on the data from the network of GPS receivers, coherent decameter radar EKB, and network of seismic stations, located near the meteorite fall trajectory. It is shown that 6-14 min after the bolide explosion, GPS network observed the cone-shaped wavefront of traveling ionospheric disturbances (TIDs) that is interpreted as a ballistic acoustic wave. The typical TIDs propagation velocity were observed 661 ± 256 m/s, which corresponds to the expected acoustic wave speed for 240 km height. Fourteen minutes after the bolide explosion, at distances of 200 km, we observed the emergence and propagation of a TID with annular wavefront that is interpreted as gravitational mode of internal atmospheric waves. The propagation velocity of this TID was 337 ± 89 m/s which corresponds to the propagation velocity of these waves in similar situations. At EKB radar, we observed TIDs in the sector of azimuthal angles close to the perpendicular to the meteorite trajectory. The observed TID velocity (400 m/s) and azimuthal properties correlate well with the model of ballistic wave propagating at 120-140 km altitude. It is shown that the azimuthal distribution of the amplitude of vertical seismic oscillations with periods 3-60 s can be described qualitatively by the model of vertical strike-slip rupture, propagating at 1 km/s along the meteorite fall trajectory to distance of about 40 km. These parameters correspond to the direction and velocity of propagation of the ballistic wave peak by the ground. It is shown that the model of ballistic wave caused by supersonic motion and burning of the meteorite in the upper atmosphere can satisfactorily explain the various azimuthal ionospheric effects, observed by the coherent decameter radar EKB, GPS receivers network, and the azimuthal characteristics of seismic waves at large distances.

  2. QUEST: QUantitative estimation of Earth's seismic sources and STructure: a European Initial Training Network

    NASA Astrophysics Data System (ADS)

    Igel, Heiner

    2010-05-01

    The Marie-Curie Initial Training Network QUEST joins scientists from 15 European partner institutions in the fields of exploration seismics, seismology, applied mathematics, high-performance computing, earthquake physics, physical inverse problems, geodynamics, from Departments of Mathematics, Physics, Earth and Computational Sciences, Oceanography and Exploration Geophysics. The main goal of QUEST is research and training in the development of strategies for seismic imaging using the increasing power of 3-D simulation technology. Existing methodologies are currently subject to a revolutionary change: While so far the observed information was severely reduced and approximate methods (e.g., ray theory) were used to determine Earth's structure, the massive increase in available computational resources allows us now to make use of the complete information contained in the observations. The QUEST objective is to integrate the various elements (wave propagation, high-performance computing, inverse problems) exploiting the synergies of the network expertise and develop the next generation of imaging tools for use on all spatial scales. The consortium is complemented by the formal partnership of one of the leading suppliers of geophysical technology to the oil and gas industry (Schlumberger Research) and Spectraseis AG (Zurich) exploiting passive imaging for industrial problems. The project offers funding for a substantial number of PhD and postdoc positons. More info at www.quest-itn.org.

  3. Caltech/USGS Southern California Seismic Network (SCSN): Infrastructure upgrade to support Earthquake Early Warning (EEW)

    NASA Astrophysics Data System (ADS)

    Bhadha, R. J.; Hauksson, E.; Boese, M.; Felizardo, C.; Thomas, V. I.; Yu, E.; Given, D. D.; Heaton, T. H.; Hudnut, K. W.

    2013-12-01

    The SCSN is the modern digital ground motion seismic network in Southern California and performs the following tasks: 1) Operates remote seismic stations and the central data processing systems in Pasadena; 2) Generates and reports real-time products including location, magnitude, ShakeMap, aftershock probabilities and others; 3) Responds to FEMA, CalOES, media, and public inquiries about earthquakes; 4) Manages the production, archival, and distribution of waveforms, phase picks, and other data at the SCEDC; 5) Contributes to development and implementation of the demonstration EEW system called CISN ShakeAlert. Initially, the ShakeAlert project was funded through the US Geological Survey (USGS) and in early 2012, the Gordon and Betty Moore Foundation provided three years of new funding for EEW research and development for the US west coast. Recently, we have also received some Urban Areas Security Initiative (UASI) funding to enhance the EEW capabilities for the local UASI region by making our system overall faster, more reliable and redundant than the existing system. The additional and upgraded stations will be capable of decreasing latency and ensuring data delivery by using more reliable and redundant telemetry pathways. Overall, this will enhance the reliability of the earthquake early warnings by providing denser station coverage and more resilient data centers than before. * Seismic Datalogger upgrade: replaces existing dataloggers with modern equipment capable of sending one-second uncompressed packets and utilizing redundant Ethernet telemetry. * GPS upgrade: replaces the existing GPS receivers and antennas, especially at "zipper array" sites near the major faults, with receivers that perform on-board precise point positioning to calculate position and velocity in real time and stream continuous data for use in EEW calculations. * New co-located seismic/GPS stations: increases station density and reduces early warning delays that are incurred by travel

  4. Improvements of Real Time First Motion Focal Mechanism and Noise Characteristics of New Sites at the Puerto Rico Seismic Network

    NASA Astrophysics Data System (ADS)

    Williams, D. M.; Lopez, A. M.; Huerfano, V.; Lugo, J.; Cancel, J.

    2011-12-01

    Seismic networks need quick and efficient ways to obtain information related to seismic events for the purposes of seismic activity monitoring, risk assessment, and scientific knowledge among others. As part of an IRIS summer internship program, two projects were performed to provide a tool for quick faulting mechanism and improve seismic data at the Puerto Rico Seismic Network (PRSN). First, a simple routine to obtain a focal mechanisms, the geometry of the fault, based on first motions was developed and implemented for data analysts routine operations at PRSN. The new tool provides the analyst a quick way to assess the probable faulting mechanism that occurred while performing the interactive earthquake location procedure. The focal mechanism is generated on-the-fly when data analysts pick P wave arrivals onsets and motions. Once first motions have been identified, an in-house PRSN utility is employed to obtain the double couple representation and later plotted using GMT's psmeca utility. Second, we addressed the issue of seismic noise related to thermal fluctuations inside seismic vaults. Seismic sites can be extremely noisy due to proximity to cultural activities and unattended thermal fluctuations inside sensor housings, thus resulting in skewed readings. In the past, seismologists have used different insulation techniques to reduce the amount of unwanted noise that a seismometers experience due to these thermal changes with items such as Styrofoam, and fiber glass among others. PRSN traditionally uses Styrofoam boxes to cover their seismic sensors, however, a proper procedure to test how these method compare to other new techniques has never been approached. The deficiency of properly testing these techniques in the Caribbean and especially Puerto Rico is that these thermal fluctuations still happen because of the intense sun and humidity. We conducted a test based on the methods employed by the IRIS Transportable Array, based on insulation by sand burial of

  5. Automatic Detection and Identification of Seismic Signals Recorded at Krakatau Volcano (Indonesia) Using Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Ibs-von Seht, M.; Kniess, R.

    2006-12-01

    A number of different event types can be observed in the records of seismic stations operated on Krakatau volcano (Indonesia). These include volcano-induced signals such as LP, VT, and hybrid-type events as well as signals not originating from the volcano such as local and regional tectonic earthquakes and transient noise signals. The work presented here aims at the realization of a system that automatically detects and identifies the signals in order to estimate and monitor current activity states of the volcano. An artificial neural network (ANN) approach was chosen for the identification task. A set of parameters were defined, describing waveform and spectrogram properties of events detected by an STA/LTA algorithm. The parameters are fed into an ANN which is, after a training phase, able to generalize input data and identify corresponding event types. The success of the identification depends on the network architecture and training strategy. Several tests have been performed in order to determine an appropriate network layout and training intensity for the given problem. The resulting network shows a good performance. A practical implementation of the system for the volcano observatory routine is sketched.

  6. 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

  7. Quantifying capability of a local seismic network in terms of locations and focal mechanism solutions of weak earthquakes

    NASA Astrophysics Data System (ADS)

    Fojtíková, Lucia; Kristeková, Miriam; Málek, Jiří; Sokos, Efthimios; Csicsay, Kristián; Zahradník, Jiří

    2016-01-01

    Extension of permanent seismic networks is usually governed by a number of technical, economic, logistic, and other factors. Planned upgrade of the network can be justified by theoretical assessment of the network capability in terms of reliable estimation of the key earthquake parameters (e.g., location and focal mechanisms). It could be useful not only for scientific purposes but also as a concrete proof during the process of acquisition of the funding needed for upgrade and operation of the network. Moreover, the theoretical assessment can also identify the configuration where no improvement can be achieved with additional stations, establishing a tradeoff between the improvement and additional expenses. This paper presents suggestion of a combination of suitable methods and their application to the Little Carpathians local seismic network (Slovakia, Central Europe) monitoring epicentral zone important from the point of seismic hazard. Three configurations of the network are considered: 13 stations existing before 2011, 3 stations already added in 2011, and 7 new planned stations. Theoretical errors of the relative location are estimated by a new method, specifically developed in this paper. The resolvability of focal mechanisms determined by waveform inversion is analyzed by a recent approach based on 6D moment-tensor error ellipsoids. We consider potential seismic events situated anywhere in the studied region, thus enabling "mapping" of the expected errors. Results clearly demonstrate that the network extension remarkably decreases the errors, mainly in the planned 23-station configuration. The already made three-station extension of the network in 2011 allowed for a few real data examples. Free software made available by the authors enables similar application in any other existing or planned networks.

  8. Grid-Search Location Methods for Ground-Truth Collection from Local and Regional Seismic Networks

    SciTech Connect

    Schultz, C A; Rodi, W; Myers, S C

    2003-07-24

    The objective of this project is to develop improved seismic event location techniques that can be used to generate more and better quality reference events using data from local and regional seismic networks. Their approach is to extend existing methods of multiple-event location with more general models of the errors affecting seismic arrival time data, including picking errors and errors in model-based travel-times (path corrections). Toward this end, they are integrating a grid-search based algorithm for multiple-event location (GMEL) with a new parameterization of travel-time corrections and new kriging method for estimating the correction parameters from observed travel-time residuals. Like several other multiple-event location algorithms, GMEL currently assumes event-independent path corrections and is thus restricted to small event clusters. The new parameterization assumes that travel-time corrections are a function of both the event and station location, and builds in source-receiver reciprocity and correlation between the corrections from proximate paths as constraints. The new kriging method simultaneously interpolates travel-time residuals from multiple stations and events to estimate the correction parameters as functions of position. They are currently developing the algorithmic extensions to GMEL needed to combine the new parameterization and kriging method with the simultaneous location of events. The result will be a multiple-event location method which is applicable to non-clustered, spatially well-distributed events. They are applying the existing components of the new multiple-event location method to a data set of regional and local arrival times from Nevada Test Site (NTS) explosions with known origin parameters. Preliminary results show the feasibility and potential benefits of combining the location and kriging techniques. They also show some preliminary work on generalizing of the error model used in GMEL with the use of mixture

  9. Earthquake location determination using data from DOMERAPI and BMKG seismic networks: A preliminary result of DOMERAPI project

    SciTech Connect

    Ramdhan, Mohamad; Nugraha, Andri Dian; Widiyantoro, Sri; Métaxian, Jean-Philippe; Valencia, Ayunda Aulia

    2015-04-24

    DOMERAPI project has been conducted to comprehensively study the internal structure of Merapi volcano, especially about deep structural features beneath the volcano. DOMERAPI earthquake monitoring network consists of 46 broad-band seismometers installed around the Merapi volcano. Earthquake hypocenter determination is a very important step for further studies, such as hypocenter relocation and seismic tomographic imaging. Ray paths from earthquake events occurring outside the Merapi region can be utilized to delineate the deep magma structure. Earthquakes occurring outside the DOMERAPI seismic network will produce an azimuthal gap greater than 180{sup 0}. Owing to this situation the stations from BMKG seismic network can be used jointly to minimize the azimuthal gap. We identified earthquake events manually and carefully, and then picked arrival times of P and S waves. The data from the DOMERAPI seismic network were combined with the BMKG data catalogue to determine earthquake events outside the Merapi region. For future work, we will also use the BPPTKG (Center for Research and Development of Geological Disaster Technology) data catalogue in order to study shallow structures beneath the Merapi volcano. The application of all data catalogues will provide good information as input for further advanced studies and volcano hazards mitigation.

  10. Sources of high frequency seismic noise: insights from a dense network of ~250 stations in northern Alsace (France)

    NASA Astrophysics Data System (ADS)

    Vergne, Jerome; Blachet, Antoine; Lehujeur, Maximilien

    2015-04-01

    Monitoring local or regional seismic activity requires stations having a low level of background seismic noise at frequencies higher than few tenths of Hertz. Network operators are well aware that the seismic quality of a site depends on several aspects, among them its geological setting and the proximity of roads, railways, industries or trees. Often, the impact of each noise source is only qualitatively known which precludes estimating the quality of potential future sites before they are tested or installed. Here, we want to take advantage of a very dense temporary network deployed in Northern Alsace (France) to assess the effect of various kinds of potential sources on the level of seismic noise observed in the frequency range 0.2-50 Hz. In September 2014, more than 250 seismic stations (FairfieldNodal@ Zland nodes with 10Hz vertical geophone) have been installed every 1.5 km over a ~25km diameter disc centred on the deep geothermal sites of Soultz-sous-Forêts and Rittershoffen. This region exhibits variable degrees of human imprints from quite remote areas to sectors with high traffic roads and big villages. It also encompasses both the deep sedimentary basin of the Rhine graben and the piedmont of the Vosges massif with exposed bedrock. For each site we processed the continuous data to estimate probability density functions of the power spectral densities. At frequencies higher than 1 Hz most sites show a clear temporal modulation of seismic noise related to human activity with the well-known variations between day and night and between weekdays and weekends. Moreover we observe a clear evolution of the spatial distribution of seismic noise levels with frequency. Basically, between 0.5 and 4 Hz the geological setting modulates the level of seismic noise. At higher frequencies, the amplitude of seismic noise appears mostly related to the distance to nearby roads. Based on road maps and traffic estimation, a forward approach is performed to model the induced

  11. A Real-Time Discrimination System of Earthquakes and Explosions for the Mainland Spanish Seismic Network

    NASA Astrophysics Data System (ADS)

    García Vargas, Marta; Rueda, Juan; García Blanco, Rosa María; Mezcua, Julio

    2016-06-01

    Different waveform-based discrimination parameters were tested using multivariate statistical analysis to develop a real-time procedure for discriminating explosions from earthquakes at regional distances in the Iberian Peninsula. This work enabled a purge of the Spanish National Seismic Catalogue for the period 2003-2014. The training data consisted of waveform-based signal properties in the time and frequency domain for events (earthquakes and explosions) recorded during the selected time period by the Spanish Broadband National Network and Sonseca short-period Array of the Instituto Geográfico Nacional (IGN). For each station and its associated training dataset, a discriminant function was defined as a linear combination of the measured variables. All station-specific discriminant functions were then combined with a weighting scheme to test the training events, revealing that 86 % of the events were consistent with the analysts' judgement. The application of this method to the whole of the IGN's seismic database for the studied period gave an 83 % success rate; however, a 91 % success rate is reached if events are classified using at least three stations and 100 % confidence levels.

  12. Universal law for waiting internal time in seismicity and its implication to earthquake network

    NASA Astrophysics Data System (ADS)

    Abe, Sumiyoshi; Suzuki, Norikazu

    2012-02-01

    In their paper (Europhys. Lett., 71 (2005) 1036), Carbone, Sorriso-Valvo, Harabaglia and Guerra showed that the "unified scaling law" for conventional waiting times of earthquakes claimed by Bak et al. (Phys. Rev. Lett., 88 (2002) 178501) is actually not universal. Here, instead of the conventional time, the concept of the internal time termed the event time is considered for seismicity. It is shown that, in contrast to the conventional waiting time, the waiting event time obeys a power law. This implies the existence of temporal long-range correlations in terms of the event time with no sharp decay of the crossover type. The discovered power-law waiting event-time distribution turns out to be universal in the sense that it takes the same form for seismicities in California, Japan and Iran. In particular, the parameters contained in the distribution take the common values in all these geographical regions. An implication of this result to the procedure of constructing earthquake networks is discussed.

  13. Automatic reconstruction of fault networks from seismicity catalogs including location uncertainty

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Ouillon, G.; Woessner, J.; Sornette, D.; Husen, S.

    2013-11-01

    introduce the anisotropic clustering of location uncertainty distributions (ACLUD) method to reconstruct active fault networks on the basis of both earthquake locations and their estimated individual uncertainties. After a massive search through the large solution space of possible reconstructed fault networks, we apply six different validation procedures in order to select the corresponding best fault network. Two of the validation steps (cross validation and Bayesian information criterion (BIC) process the fit residuals, while the four others look for solutions that provide the best agreement with independently observed focal mechanisms. Tests on synthetic catalogs allow us to qualify the performance of the fitting method and of the various validation procedures. The ACLUD method is able to provide solutions that are close to the expected ones, especially for the BIC and focal mechanism-based techniques. The clustering method complemented by the validation step based on focal mechanisms provides good solutions even in the presence of a significant spatial background seismicity rate. Our new fault reconstruction method is then applied to the Landers area in Southern California and compared with previous clustering methods. The results stress the importance of taking into account undersampled subfault structures as well as of the spatially inhomogeneous location uncertainties.

  14. 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.

  15. Real-time detection, location, and characterization of rockslides using broadband regional seismic networks

    NASA Astrophysics Data System (ADS)

    Manconi, Andrea; Picozzi, Matteo; Coviello, Velio; De Santis, Francesca; Elia, Luca

    2016-07-01

    We propose a new real-time approach to detect, locate, and estimate the volume of rockslides by analyzing waveforms acquired from broadband regional seismic networks. The identification of signals generated by rockslides from other sources, such as natural and/or induced earthquakes, is accomplished by exploiting the ratio between local magnitudes (ML) and duration magnitudes (MD). We found that signals associated with rockslides have ML/MD < 0.8, while for earthquakes ML/MD ≅ 1. In addition, we derived an empirical relationship between MD and rockslide volumes, obtaining a preliminary characterization of rockslide volume within seconds after their occurrence. The key points of this study are presented by testing the hypothesis on a recent rockslide event that occurred in northern Italy. We discuss also the potential evolution of the methodology for early warning and/or rapid response purposes.

  16. Aspects regarding the use of the INFREP network for identifying possible seismic precursors

    NASA Astrophysics Data System (ADS)

    Dolea, Paul; Cristea, Octavian; Dascal, Paul Vladut; Moldovan, Iren-Adelina; Biagi, Pier Francesco

    In the last decades, one of the main research directions in identifying seismic precursors involved monitoring VLF (Very Low Frequency) and LF (Low Frequency) radio waves and analysing their propagation characteristics. Essentially this method consists of monitoring different available VLF and LF transmitters from long distance reception points. The received signal has two major components: the ground wave and the sky wave, where the sky wave propagates by reflection on the lower layers of the ionosphere. It is assumed that before and during major earthquakes, unusual changes may occur in the lower layers of the ionosphere, such as the modification of the charged particles number density and the altitude of the reflection zone. Therefore, these unusual changes in the ionosphere may generate unusual variations in the received signal level. The International Network for Frontier Research on Earthquake Precursors (INFREP) was developed starting with 2009 and consists of several dedicated VLF and LF radio receivers used for monitoring various radio transmitters located throughout Europe. The receivers' locations were chosen so that the propagation path from these VLF/LF stations would pass over high seismicity regions while others were chosen to obtain different control paths. The monitoring receivers are capable of continuously measuring the received signal amplitude from the VLF/LF stations of interest. The recorded data is then stored and sent to an INFREP database, which is available on the Internet for scientific researchers. By processing and analysing VLF and LF data samples, collected at different reception points and at different periods of the year, one may be able to identify some distinct patterns in the envelope of the received signal level over time. Significant deviations from these patterns may have local causes such as the electromagnetic pollution at the monitoring point, regional causes like existing electrical storms over the propagation path or

  17. Information system evolution at the French National Network of Seismic Survey (BCSF-RENASS)

    NASA Astrophysics Data System (ADS)

    Engels, F.; Grunberg, M.

    2013-12-01

    The aging information system of the French National Network of Seismic Survey (BCSF-RENASS), located in Strasbourg (EOST), needed to be updated to satisfy new practices from Computer science world. The latter means to evolve our system at different levels : development method, datamining solutions, system administration. The new system had to provide more agility for incoming projects. The main difficulty was to maintain old system and the new one in parallel the time to validate new solutions with a restricted team. Solutions adopted here are coming from standards used by the seismological community and inspired by the state of the art of devops community. The new system is easier to maintain and take advantage of large community to find support. This poster introduces the new system and choosen solutions like Puppet, Fabric, MongoDB and FDSN Webservices.

  18. The Lunar Seismic Network (LuSeN) Mission: The Need for Compact, Robust, Long-Lived Power Supplies.

    NASA Astrophysics Data System (ADS)

    Neal, C. R.

    2005-12-01

    The Apollo seismic experiment established a network of four seismometers on the lunar nearside at the Apollo 12, 14, 15 and 16 landing sites that was in operation for 8 years (1969-1977). During this time, four different types of moonquakes were recognized and although originally thought to be tectonically dead, the recorded activity showed that lunar seismicity was about equal to that of intraplate settings on Earth. However, the limited spatial coverage of this network has left many unanswered questions, such as: 1) What is the structure and thickness of the crust on the lunar near and far sides? Are crustal structure changes gradational or are distinct domains present? What is the nature of the hypothesized lunar core? What are the mineralogic transitions present in the lunar mantle? Is there a Moon-wide ~500 km discontinuity (magmasphere vs. magma ocean)? Are the core and mantle completely solid or do plastic zones still persist? Are nests producing periodic deep Moonquakes present on the far side? The Lunar Seismic Network (LuSeN) mission concept establishes a modest network of 8-10 seismometers deployed around the Moon with an orbiting communications satellite. Like the Apollo seismic experiment, these seismometers need to be continuously recording and be active for 5-7 years in order to record enough seismic events to establish where the most seismically active areas are in the Moon, as well as answer the scientific questions outlined above. Mass considerations preclude establishing a network of this size using conventional battery and solar power supplies: a compact, robust radionuclear power supply is needed for each seismometer. Given the new emphasis on the Moon, results from the LuSeN mission will be relevant for the establishing a Moon base in a seismically passive (safe) region and one that has a low probability of receiving a sizable meteoroid impact. In addition, the LuSeN mission will also use the Moon as a technology test bed for establishing

  19. Application of Artificial Neural Networks for the classification of the seismic transients at Soufrière Hills volcano, Montserrat

    NASA Astrophysics Data System (ADS)

    Langer, H.; Falsaperla, S.; Thompson, G.

    2003-11-01

    Seismic activity at Soufrière Hills volcano is characterized by a variety of transients, such as tectonic earthquakes, long-period events, hybrid events, and rockfalls. The huge quantity of seismic data daily recorded on the volcano makes the application of automatic processing highly recommendable. We propose a method of supervised classification of the transients based on Artificial Neural Networks (ANN), which may be useful for processing the large data sets piled up in the past. Particularly, data sets recorded before the climactic eruptions from 1995 to 2002 may allow us to reconstruct the distribution of the different classes of seismic transients in time. We believe that this analysis may give useful insights into impending eruptive scenarios. The good performance of the ANN with 70% of transients correctly classified in a test set of 156 data, along with the opportunity to revise the misfits, make ANN a powerful tool for data processing.

  20. Seismic data classification and artificial neural networks: can software replace eyeballs?

    NASA Astrophysics Data System (ADS)

    Reusch, D. B.; Larson, A. M.

    2006-05-01

    Modern seismic datasets are providing many new opportunities for furthering our understanding of our planet, ranging from the deep earth to the sub-ice sheet interface. With many geophysical applications, the large volume of these datasets raises issues of manageability in areas such as quality control (QC) and event identification (EI). While not universally true, QC can be a labor intensive, subjective (and thus not entirely reproducible) and uninspiring task when such datasets are involved. The EI process shares many of these drawbacks but has the benefit of (usually) being closer to interesting science-based questions. Here we explore two techniques from the field of artificial neural networks (ANNs) that seek to reduce the time requirements and increase the objectivity of QC and EI on seismic datasets. In particular, we focus on QC of receiver functions from broadband seismic data collected by the 2000-2003 Transantarctic Mountains Seismic Experiment (TAMSEIS). Self-organizing maps (SOMs) enable unsupervised classification of large, complex geophysical data sets (e.g., time series of the atmospheric circulation) into a fixed number of distinct generalized patterns or modes representing the probability distribution function of the input data. These patterns are organized spatially as a two-dimensional grid such that distances represent similarity (adjacent patterns will be most similar). After training, input data are matched to their most similar generalized pattern to produce frequency maps, i.e., what fraction of the data is represented best by each individual SOM pattern. Given a priori information on data quality (from previous manual grading) or event type, a probabilistic classification can be developed that gives a likelihood for each category of interest for each SOM pattern. New data are classified by identifying the closest matching pattern (without retraining) and examining the associated probabilities. Feed-forward ANNs (FFNNs) are a supervised

  1. Seismic features and automatic discrimination of deep and shallow induced-microearthquakes using neural network and logistic regression

    NASA Astrophysics Data System (ADS)

    Mousavi, S. Mostafa; Horton, Stephen, P.; Langston, Charles A.; Samei, Borhan

    2016-07-01

    We develop an automated strategy for discriminating deep microseismic events from shallow ones on the basis of the waveforms recorded on a limited number of surface receivers. Machine-learning techniques are employed to explore the relationship between event hypocenters and seismic features of the recorded signals in time, frequency, and time-frequency domains. We applied the technique to 440 microearthquakes -1.7seismic attributes of whole seismograms including degree of polarization and spectral attributes were measured. A selected set of features was then used to train the system to discriminate between deep and shallow events based on the knowledge gained from existing patterns. The cross validation test showed that events with depth shallower than 250 m can be discriminated from events with hypocentral depth between 1000 to 2000 m with 88% and 90.7% accuracy using logistic regression (LR) and artificial neural network (ANN) models, respectively. Similar results were obtained using single station seismograms. The results show that the spectral features have the highest correlation to source depth. Spectral centroids and 2D cross-correlations in the time-frequency domain are two new seismic features used in this study that showed to be promising measures for seismic event classification. The used machine learning techniques have application for efficient automatic classification of low energy signals recorded at one or more seismic stations.

  2. Seismicity in 2010 and major earthquakes recorded and located in Costa Rica from 1983 until 2012, by the local OVSICORI-UNA seismic network

    NASA Astrophysics Data System (ADS)

    Ronnie, Q.; Segura, J.; Burgoa, B.; Jimenez, W.; McNally, K. C.

    2013-05-01

    This work is the result of the analysis of existing information in the earthquake database of the Observatorio Sismológico y Vulcanológico de Costa Rica, Universidad Nacional (OVSICORI-UNA), and seeks disclosure of basic seismological information recorded and processed in 2010. In this year there was a transition between the software used to record, store and locate earthquakes. During the first three months of 2010, we used Earthworm (http://folkworm.ceri.memphis.edu/ew-doc), SEISAN (Haskov y Ottemoller, 1999) and Hypocenter (Lienert y Haskov, 1995) to capture, store and locate the earthquakes, respectively; in April 2010, ANTELOPE (http://www.brtt.com/software.html) start to be used for recording and storing and GENLOC (Fan at al, 2006) and LOCSAT (Bratt and Bache 1988), to locate earthquakes. GENLOC was used for local events and LOCSAT for regional and distant earthquakes. The local earthquakes were located using the 1D velocity model of Quintero and Kissling (2001) and for regional and distant earthquakes IASPEI91 (Kennett and Engdahl, 1991) was used. All the events for 2010 and shown in this work were rechecked by the authors. We located 3903 earthquakes in and around Costa Rica and 746 regional and distant seismic events were recorded (see Figure 1). In this work we also give a summary of major earthquakes recorded and located by OVSICORI-UNA network between 1983 and 2012. Seismicity recorded by OVSICORI-UNA network in 2010

  3. Bayesian inference of Earth's radial seismic structure from body-wave traveltimes using neural networks

    NASA Astrophysics Data System (ADS)

    de Wit, Ralph W. L.; Valentine, Andrew P.; Trampert, Jeannot

    2013-10-01

    How do body-wave traveltimes constrain the Earth's radial (1-D) seismic structure? Existing 1-D seismological models underpin 3-D seismic tomography and earthquake location algorithms. It is therefore crucial to assess the quality of such 1-D models, yet quantifying uncertainties in seismological models is challenging and thus often ignored. Ideally, quality assessment should be an integral part of the inverse method. Our aim in this study is twofold: (i) we show how to solve a general Bayesian non-linear inverse problem and quantify model uncertainties, and (ii) we investigate the constraint on spherically symmetric P-wave velocity (VP) structure provided by body-wave traveltimes from the EHB bulletin (phases Pn, P, PP and PKP). Our approach is based on artificial neural networks, which are very common in pattern recognition problems and can be used to approximate an arbitrary function. We use a Mixture Density Network to obtain 1-D marginal posterior probability density functions (pdfs), which provide a quantitative description of our knowledge on the individual Earth parameters. No linearization or model damping is required, which allows us to infer a model which is constrained purely by the data. We present 1-D marginal posterior pdfs for the 22 VP parameters and seven discontinuity depths in our model. P-wave velocities in the inner core, outer core and lower mantle are resolved well, with standard deviations of ˜0.2 to 1 per cent with respect to the mean of the posterior pdfs. The maximum likelihoods of VP are in general similar to the corresponding ak135 values, which lie within one or two standard deviations from the posterior means, thus providing an independent validation of ak135 in this part of the radial model. Conversely, the data contain little or no information on P-wave velocity in the D'' layer, the upper mantle and the homogeneous crustal layers. Further, the data do not constrain the depth of the discontinuities in our model. Using additional

  4. 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

  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

    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. The implementation of a volcano seismic monitoring network in Sete Cidades Volcano, São Miguel, Açores

    NASA Astrophysics Data System (ADS)

    Wallenstein, N.; Montalvo, A.; Barata, U.; Ortiz, R.

    2003-04-01

    Sete Cidades is one of the three active central volcanoes of S. Miguel Island, in the Azores archipelago. With a 5 kilometres wide caldera, it has the highest eruptive record in the last 5000 years with 17 intracaldera explosive events (Queiroz, 1997). Only submarine volcanic eruptions occurred in Sete Cidades volcano-tectonic system since the settlement of the island, in the 15th century. Small seismic swarms, some of which were interpreted as being related with magmatic and/or deep hydrothermal origin, characterize the most recent seismo-volcanic activity of Sete Cidades volcano. To complement the regional seismic network, operating since the early 80's, a new local seismic network was designed and installed at Sete Cidades Volcano. It includes 5 digital stations being one 5-seconds three-component station located inside the caldera and four 10-seconds one-component stations placed on the caldera rim. The solution found for the digital telemetry is based on UHF 19,2 Kbps radio modems linking four of the seismic stations to a central point, where the fifth station is installed. At this site, signals are synchronised with a GPS receiver, stored in a PC and re-transmitted to the Azores University Volcanological Observatory by an 115,2 Kbps Spread Spectrum 2.4 Ghz Radio Modem Network. Seismic signal tests carried out in all the area showed that cultural and sea noise, as well as some scattering effects due to the geological nature of the terrain (composed by thick pumice and ash deposits) and the topographic effects are factors that can not be avoidable and will be present in future records. This low cost network with locally developed and assembled components, based on short-period sensors without signal filtering in the field and digital telemetry, will improve the detection and location of low magnitude events in the Sete Cidades volcano area. Future developments of this program will include the installation of a seismic array inside the caldera to identify and

  7. Automatic re-picking and re-weighting of first arrival times from the Italian Seismic Network waveforms database

    NASA Astrophysics Data System (ADS)

    di Stefano, R.; Amato, A.; Aldersons, F.; Kissling, E.

    2002-12-01

    The high resolution P-wave tomography of the Italian Peninsula and surrounding regions from crustal to upper mantle depths is the aim of a joint project between INGV (Roma) and ETH (Zurich). The project is subdivided into two steps, first of which is to establish a 3D P-wave velocity model for the crust, using both passive and active seismic sources. Getting a reliable high resolution model is of fundamental importance since the 3D crustal model will be used in the second step to correct teleseismic travel times following a method successfully applied in the last years to the Alps (Waldhauser et al. 2002). In the present work we focus on the passive sources dataset (local and regional events) to complement the CSS crustal information. Our keywords being "high-resolution" and "detailed model" we followed the idea, based on the experience of previous works in this area, that a large number of high quality pickings and a high level of consistency in the dataset represent the first goals. The Italian region (Western Mediterranean) is characterized by a high rate of seismicity including important seismic sequences. Since 1988, digital recordings for about 40,000 local and regional earthquakes are available, which INGV bulletin readings have been used in previous local earthquake tomography works. To increase the sampling power and to better locate some border events we will integrate Italian National Seismic Network data with recordings from other local and regional networks. Due to the large amount of data thus collected, a manual re-picking of all first arrivals would ask for a too long time while it would not prevent from human readings errors and inconsistencies. This would partially contrast the positive effect of a high-quality pickings. To meet the quality and consistency requests, we applied an advanced automatic re-picking procedure, the MannekenPick (MP), recently developed by F. Aldersons as a fast, reliable and "consistent" picker. We tested the whole

  8. Importance of Stratabound Fracture Networks for Seismic Hazard Assessment of Hydraulic Fracturing

    NASA Astrophysics Data System (ADS)

    Eaton, D. W.; Davidsen, J.; Pedersen, P. K.; Boroumand, N.

    2013-12-01

    Hydraulic fracturing, a powerful completion technique used to enhance oil or gas production from impermeable strata, may trigger unintended earthquake activity. The primary basis for assessment of triggered and natural seismic hazard is the classic Gutenberg-Richter (G-R) relation, which expresses scale-independent behavior of earthquake magnitudes. Using a stochastic approach to simulate microseismicity from three monitoring programs in North America, we show that magnitude-distance trends for microearthquakes induced by hydraulic fracturing may deviate significantly from the G-R relation. This apparent breakdown in the power-law scaling paradigm, coupled with unusually high values for the b-parameter (slope) of the G-R relation, can be explained by a new model based on activation of stratabound fracture networks in which fracture height growth is limited by mechanical bed thickness. For the three areas considered, mechanical bed thickness is well represented by a lognormal distribution, which leads asymptotically to a Gaussian decay for induced magnitudes that fits the observations remarkably well. This new relationship has profound implications for understanding the scaling behavior of induced microearthquakes, as well as for forecasting the probability of larger earthquakes triggered by hydraulic fracturing in oil and gas development.

  9. Southern California Seismic Network: New Design and Implementation of Redundant and Reliable Real-time Data Acquisition Systems

    NASA Astrophysics Data System (ADS)

    Saleh, T.; Rico, H.; Solanki, K.; Hauksson, E.; Friberg, P.

    2005-12-01

    The Southern California Seismic Network (SCSN) handles more than 2500 high-data rate channels from more than 380 seismic stations distributed across southern California. These data are imported real-time from dataloggers, earthworm hubs, and partner networks. The SCSN also exports data to eight different partner networks. Both the imported and exported data are critical for emergency response and scientific research. Previous data acquisition systems were complex and difficult to operate, because they grew in an ad hoc fashion to meet the increasing needs for distributing real-time waveform data. To maximize reliability and redundancy, we apply best practices methods from computer science for implementing the software and hardware configurations for import, export, and acquisition of real-time seismic data. Our approach makes use of failover software designs, methods for dividing labor diligently amongst the network nodes, and state of the art networking redundancy technologies. To facilitate maintenance and daily operations we seek to provide some separation between major functions such as data import, export, acquisition, archiving, real-time processing, and alarming. As an example, we make waveform import and export functions independent by operating them on separate servers. Similarly, two independent servers provide waveform export, allowing data recipients to implement their own redundancy. The data import is handled differently by using one primary server and a live backup server. These data import servers, run fail-over software that allows automatic role switching in case of failure from primary to shadow. Similar to the classic earthworm design, all the acquired waveform data are broadcast onto a private network, which allows multiple machines to acquire and process the data. As we separate data import and export away from acquisition, we are also working on new approaches to separate real-time processing and rapid reliable archiving of real-time data

  10. Cataloguing Seismic Waveform Properties Recorded With a 3D Network in a Gold Mine in South Africa

    NASA Astrophysics Data System (ADS)

    Julia, J.; Nyblade, A. A.; Gok, R.; Walter, W. R.; Linzer, L.; Durrheim, R. J.; Dirks, P.

    2007-12-01

    The SAVUKA gold mine is located in the northwestern edge of the Witwatersrand basin, a Late Archean (3.07- 2.71~Ga) intracratonic basin in South Africa that hosts the largest known gold-uranium-pyrite ore deposits in the world. Seismic events related to the mine activity span several orders of magnitude through a variety of sources that include mine blasts, pillar collapses, and faulting events. These events are systematically recorded and catalogued through an in-mine, 3D seismic network consisting of 20, three-component, short-period stations with natural frequencies ranging between 4.5 and 28.0~Hz and deployed as deep as ~3.5 km. After 5 months of seismic monitoring of the mine, we have been able to assemble a database of over 6000 events spanning magnitudes in the -2.5 < ML < 4.4 range. The potential of this unique data set for characterizing the detailed seismic properties of the basin and studying source properties of non-double couple events is explored through simple, first-pass analysis on the recorded waveforms. Moreover, the in-mine network is complemented by a small array of 4 broadband stations interspaced ~10~km apart on the surface of the mine, and by a number of AfricaArray stations in South Africa and neighboring countries located at regional distances (50- 1000~km) from the mine. The largest mine-induced events are clearly recorded at distances as far away from the mine as 450~km and provide a unique opportunity for studying the regional propagation of seismic phases as well as the structure of the cratonic crust underlying the basin.

  11. Los Alamos National Laboratory.

    ERIC Educational Resources Information Center

    Hammel, Edward F., Jr.

    1982-01-01

    Current and post World War II scientific research at the Los Alamos National Laboratory (New Mexico) is discussed. The operation of the laboratory, the Los Alamos consultant program, and continuation education, and continuing education activities at the laboratory are also discussed. (JN)

  12. 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

  13. Looking for underlying features in automatic and reviewed seismic bulletins through a neural network

    NASA Astrophysics Data System (ADS)

    Carluccio, R.; Console, R.; Chiappini, M.; Chiappini, S.

    2009-12-01

    SEL1 bulletins are, among all IDC products, a fundamental tool for NDCs in their task of national assessment of compliance with the CTBT. This is because SEL1s are expected to be disseminated within 2 hours from the occurrence of any detected waveform event, and the National Authorities are supposed to take a political decision in nearly real time, especially in the case when the event could triggers the request for an on site inspection. In this context not only the rapidity, but also the reliability of the SEL1 is a fundamental requirement. Our last years experience gained in the comparison between SEL1 and Italian Seismic Bulletin events has shown that SEL1s usually contain a big fraction of bogus events (sometimes close to 50%). This is due to many factors, all related to the availability of processing data and to the fast automatic algorithms involved. On the other hand, REBs are much more reliable as proved by our experience. Therefore, in spite of their relevant time delay by which they are distributed, which prevents their real-time use, REBs can be still useful in a retrospective way as reference information for comparison with SEL1s. This study tries to set up a sort of logical filter on the SEL1s that, while maintaining the rapidity requirements, improves their reliability. Our idea is based on the assumption that the SEL1s are produced by systematic algorithm of phase association and therefore some patterns among the input and output data could exist and be recognized. Our approach was initially based on a set of rules suggested by human experts on their personal experience, and its application on large datasets on a global scale. Other approaches not involving human interaction (data mining techniques) do exist. This study refers specifically to a semi-automatic approach: fitting of multi-parametric relationships hidden in the data set, through the application of neural networks by an algorithm of supervised learning. Full SEL1 and REB bulletins from

  14. Weather-related Ground Motions Recorded by Taiwan Broadband Seismic Network Stations

    NASA Astrophysics Data System (ADS)

    Yang, C. F.; Chi, W. C.

    2014-12-01

    Broadband seismometers record ground motions, which can be induced by weather-related processes. Analyzing such signals might help to better understand those natural processes. Previously, abnormal seismic signals have been detected during rainfall and snowmelt events. The amplitudes of those seismic signals correlated with the variations of the discharge in a nearby river and scientists have proposed that such signals were generated by bed load transport. Here, we used the continuous seismic data from the Broadband Array in Taiwan for Seismology (BATS) to analyze the weather-related ground motions during rainfall events. The sampling rate for seismic data is 100 samples per second. We compared the seismic data with the precipitation data from the rain gauge stations in Taiwan in three select rainfall periods, Typhoon Kalmaegi in 2008, Typhoon Morakot in 2009 and the East Asian rainy season in 2012. During raining, the Power Spectral Density (PSD) of high frequency (> 1 Hz) seismic noises is apparently high, and the amplitude of the seismic noise also correlates with the local precipitation, especially at the stations in the drainage basins, and the PSD decreased gradually after peaks of precipitation. At some seismic stations, we observed vertical ground motions at several bands of frequencies: 0-1 Hz, 1-5 Hz, and 5-45 Hz. However, on horizontal components we found the 5-45 Hz energy splits into two bands: 5-25 Hz and 30-45 Hz. For stations near the ridge tops or on the coastal plain, the 30-45 Hz band energy is weaker or missing. Preliminary results show that the amplitudes of the seismic waves correlate with the stream flow discharge. Next, we plan to study the sources of the different bands of energy to examine if we can monitor and quantify natural processes, like precipitation and river discharge, using seismic signals.

  15. Mining induced seismic event on an inactive fault in view of local surface and in mine underground networksS

    NASA Astrophysics Data System (ADS)

    Rudzinski, Lukasz; Lizurek, Grzegorz; Plesiewicz, Beata

    2014-05-01

    On 19th March 2013 tremor shook the surface of Polkowice town were "Rudna" mine is located. This event of ML=4.2 was third most powerful seismic event recorded in Legnica Głogów Copper District (LGCD). Citizens of the area reported that felt tremors were bigger and last longer than any other ones felt in last couple years. The event was studied with use of two different networks: underground network of "Rudna" mine and surface local network run by IGF PAS (LUMINEOS network). The first one is composed of 32 vertical seismometers at mining level, except 5 sensors placed in elevator shafts, seismometers location depth varies from 300 down to 1000 meters below surface. The seismometers used in this network are vertical short period Willmore MkII and MkIII sensors, with the frequency band from 1Hz to 100Hz. At the beginning of 2013th the local surface network of the Institute of Geophysics Polish Academy of Sciences (IGF PAS) with acronym LUMINEOS was installed under agreement with KGHM SA and "Rudna" mine officials. This network at the moment of the March 19th 2013 event was composed of 4 short-period one-second triaxial seismometers LE-3D/1s manufactured by Lenartz Electronics. Analysis of spectral parameters of the records from in mine seismic system and surface LUMINEOS network along with broadband station KSP record were carried out. Location of the event was close to the Rudna Główna fault zone, the nodal planes orientations determined with two different approaches were almost parallel to the strike of the fault. The mechanism solutions were also obtained in form of Full Moment Tensor inversion from P wave amplitude pulses of underground records and waveform inversion of surface network seismograms. Final results of the seismic analysis along with macroseismic survey and observed effects from the destroyed part of the mining panel indicate that the mechanism of the event was thrust faulting on inactive tectonic fault. The results confirm that the fault zones

  16. Application of Network-averaged Teleseismic P-wave Spectra to Seismic Yield Estimation of Underground Nuclear Explosions

    NASA Astrophysics Data System (ADS)

    Murphy, J. R.; Barker, B. W.

    - A set of procedures is described for estimating network-averaged teleseismic P-wave spectra for underground nuclear explosions and for analytically inverting these spectra to obtain estimates of mb/yield relations and individual yields for explosions at previously uncalibrated test sites. These procedures are then applied to the analyses of explosions at the former Soviet test sites at Shagan River, Degelen Mountain, Novaya Zemlya and Azgir, as well as at the French Sahara, U.S. Amchitka and Chinese Lop Nor test sites. It is demonstrated that the resulting seismic estimates of explosion yield and mb/yield relations are remarkably consistent with a variety of other available information for a number of these test sites. These results lead us to conclude that the network-averaged teleseismic P-wave spectra provide considerably more diagnostic information regarding the explosion seismic source than do the corresponding narrowband magnitude measures such as mb, Ms and mb(Lg), and, therefore, that they are to be preferred for applications to seismic yield estimation for explosions at previously uncalibrated test sites.

  17. Regional Characterization of Tokyo Metropolitan area using a highly-dense seismic network (MeSO-net)

    NASA Astrophysics Data System (ADS)

    Hirata, Naoshi; Nakagawa, Shigeki; Sakai, Shin'ichi; Panayotopoulos, Yannis; Ishikawa, Masahiro; Ishibe, Takeo; Kimura, Hisanori; Honda, Ryou

    2015-04-01

    We have developed a dense seismic network, MeSO-net (Metropolitan Seismic Observation network), which consists of about 300 seismic stations, since 2007 in the greater Tokyo urban region(Hirata et al., 2009). Using MeSO-net data, we obtain P- and S- wave velocity tomograms (Nakagawa et al., 2010) and Qp, Qs tomograms (Panayotopoulos et al., 2014) which show a clear image of Philippine Sea Plate (PSP) and PAcific Plate (PAP). A depth to the top of PSP, 20 to 30 km beneath northern part of Tokyo bay, is about 10 km shallower than previous estimates based on the hypocenter distribution (Ishida, 1992). Based on elastic wave velocities of rocks and minerals, we constructed a petrologic model. The Vp steps in subducting Izu forearc crust occurs at a depth of 30km (blueschist or greenschist to garnet amphibolite transformation) and a depth of 50km (garnet amphibolite to eclogite transformation). Both temperatures are estimated to be 500 and 600 degree C, respectively. The high Vp/Vs anomaly (>1.9) implies large amounts of fluid H2O released by garnet amphibolite to eclogite dehydration reactions. This study is supported by MEXT Japan under the Special Project for Reducing Vulnerability for Urban Mega Earthquake Disasters.

  18. Evolution of Permeability and Induced Seismicity during Reservoir Stimulation; Role of Fluid Pressure and Thermal Transients on Reactivated Fractured Networks

    NASA Astrophysics Data System (ADS)

    Izadi, G.; Elsworth, D.

    2012-12-01

    We utilize a continuum model of reservoir behavior subject to coupled THMC (thermal, hydraulic, mechanical and chemical) processes to explore the evolution of stimulation-induced seismicity and of permeability in EGS reservoirs. Our continuum model is capable of accommodating changes in effective stresses that result due to the evolving spatial variations in fluid pressure as well as thermal stress and chemical effects. Discrete penny-shaped fractures (~10-1200m) are seeded within the reservoir volume at prescribed (faults) and random (fractures) orientations and with a Gaussian distribution of lengths and location. Failure is calculated from a continuum model using a Coulomb criterion for friction. Energy release magnitude is utilized to obtain the magnitude-moment relation for induced seismicity by location and with time. This model is applied to a single injector (stimulation) to the proposed Newberry EGS field (USA). We stimulate the reservoir in four zones of differing fracture network properties B, C, D and E (shallow to deep) and at four different depths of 2000, 2500, 2750 and 3000 m. The same network of large fractures (density of 0.003 m-1 and spacing 300 m) is applied in all zones and supplemented by more closely spaced fractures with densities of 0.5 m-1 in the shallow zone B, 0.9 m-1 in the intermediate zones C and D and 0.26 m-1 in the deepest zone E. We show that permeability enhancement is modulated by hydraulic, thermal, and chemical (THMC) processes and that permeability increases by an order of magnitude during stimulation at each depth. For the widely spaced fracture networks, the increase in permeability reaches a smaller radius from the injection point and permeability evolution is slower with time compared to the behavior of the closely spaced fracture network. For seismic events that develop with the stimulation, event magnitude (MS) varies in the range -2 to +1.9 and the largest event size (~1.9) corresponds to the largest fractures (~1200m

  19. Could the IMS Infrasound Stations Support a Global Network of Small Aperture Seismic Arrays?

    NASA Astrophysics Data System (ADS)

    J, Gibbons, Steven; Kværna, Tormod; Mykkeltveit, Svein

    2015-04-01

    The infrasound stations of the International Monitoring System are arrays consisting of up to 15 sites and with apertures of up to 3 km. The arrays are distributed remarkably uniformly over the globe and provide excellent coverage of South America, Africa, and Antarctica. This is to say that there are many infrasound arrays in regions many thousands of kilometers from the closest seismic array. Several infrasound arrays are in the immediate vicinity of existing 3-component seismic stations and these provide us with examples of how typical seismic signals look at these locations. We can make idealized estimates of the predicted performance of seismic arrays, consisting of seismometers at each site of the infrasound arrays, by duplicating the signals from the 3-C stations at all sites of the array. However, the true performance of seismic arrays at these sites will depend both upon Signal-to-Noise Ratios of seismic signals and the coherence of both signal and noise between sensors. These properties can only be determined experimentally. Recording seismic data of sufficient quality at many of these arrays may require borehole deployments since the microbarometers in the infrasound arrays are often situated in vaults placed in soft sediments. The geometries of all the current IMS infrasound arrays are examined and compared and we demonstrate that, from a purely geometrical perspective, essentially all the array configurations would provide seismic arrays with acceptable slowness resolution for both regional and teleseismic phase arrivals. Seismic arrays co-located with the infrasound arrays in many regions would likely enhance significantly the seismic monitoring capability in parts of the world where only 3-component stations are currently available. Co-locating seismic and infrasound sensors would facilitate the development of seismic arrays that share the infrastructure of the infrasound arrays, reducing the development and operational costs. Hosting countries might

  20. Development of an event search and download system for analyzing waveform data observed at seafloor seismic network, DONET

    NASA Astrophysics Data System (ADS)

    Takaesu, M.; Horikawa, H.; Sueki, K.; Kamiya, S.; Nakamura, T.; Nakano, M.; Takahashi, N.; Sonoda, A.; Tsuboi, S.

    2014-12-01

    Mega-thrust earthquakes are anticipated to occur in the Nankai Trough in southwest Japan. In the source areas, we installed 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; strong-motion and broadband seismometers, quartz and differential pressure gauges, hydrophone, and thermometer. The stations are densely distributed with an average spatial interval of 15-20 km and cover near coastal areas to the trench axis. 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. The data are based on WIN32 format in the private network and finally archived in SEED format in the management center to combine waveform data with related metadata. We are developing a web-based application system to easily download seismic waveform data of DONET. In this system, users can select 20 Hz broadband (BH type) and 200 Hz strong-motion (EH type) data and download them in SEED. Users can also search events from the options of time periods, magnitude, source area and depth in a GUI platform. Event data are produced referring to event catalogues from USGS and JMA (Japan Meteorological Agency). The thresholds of magnitudes for the production are M6 for far-field and M4 for local events using the USGS and JMA lists, respectively. Available data lengths depend on magnitudes and epicentral distances. In this presentation, we briefly introduce DONET stations and then show our developed application system. We open DONET data through the system and want them to be widely recognized so that many users analyze. We also discuss next plans for further developments of the system.

  1. Grid-Search Location Methods for Ground-Truth Collection From Local and Regional Seismic Networks

    SciTech Connect

    William Rodi; Craig A. Schultz; Gardar Johannesson; Stephen C. Myers

    2005-05-13

    This project investigated new techniques for improving seismic event locations derived from regional and local networks. The technqiues include a new approach to empirical travel-time calibration that simultaneously fits data from multiple stations and events, using a generalization of the kriging method, and predicts travel-time corrections for arbitrary event-station paths. We combined this calibration approach with grid-search event location to produce a prototype new multiple-event location method that allows the use of spatially well-distributed events and takes into account correlations between the travel-time corrections from proximate event-station paths. Preliminary tests with a high quality data set from Nevada Test Site explosions indicated that our new calibration/location method offers improvement over the conventional multiple-event location methods now in common use, and is applicable to more general event-station geometries than the conventional methods. The tests were limited, however, and further research is needed to fully evaluate, and improve, the approach. Our project also demonstrated the importance of using a realistic model for observational errors in an event location procedure. We took the initial steps in developing a new error model based on mixture-of-Gaussians probability distributions, which possess the properties necessary to characterize the complex arrival time error processes that can occur when picking low signal-to-noise arrivals. We investigated various inference methods for fitting these distributions to observed travel-time residuals, including a Markov Chain Monte Carlo technique for computing Bayesian estimates of the distribution parameters.

  2. Evaluation of the imminence of a tsunami based on real-time seismic source parameter estimates - a Bayesian network approach

    NASA Astrophysics Data System (ADS)

    Blaser, Lilian; Ohrnberger, Matthias; Scherbaum, Frank

    2010-05-01

    Tsunami early warnings are based on co-seismic evidences being the earliest available information from a hazardous earthquake with the potential of causing a tsunami. Evaluations are generally done by applying rules derived from historic observation and making use of seismological expertise regarding regional tectonic contexts, faulting styles, occurrence frequency of large earthquakes and more. However, the co-seismic generation of a tsunami as well as the estimation of a potentially tsunamigenic event is prone to various uncertainties. As Bayesian networks (BNs) allow for integration and quantification of the uncertainties within the framework of probabilistic graphical models, we propose the usage of BNs for evaluating the imminence of a tsunami based on real-time seismic source parameter estimates. Earthquake parameter estimates (including uncertainties) are evaluated in real-time and the probabilities of tsunami threat levels are calculated and updated whenever new co-seismic evidence is available. The fast and efficient method gives an important additional information for the staff members at tsunami warning centers as it provides a probabilistic overview on the imminence of a tsunami for some particular costal region. In our work, we have developed a preliminary BN tsunami warning system for the region of Sumatra by extracting knowledge from a set of formulas describing the physical process from earthquake rupture to sea-floor deformation to tsunami wave propagation and finally shoaling at the coast. The physical knowledge was transformed by ancestral sampling to a synthetic database and thereof BNs were learned for several sites of interest along the Sumatran coast and the fore-arc islands. To determine the conditional probability of the tsunami amplitude a set of seven co-seismic variables was defined: epicenter, centroid, magnitude, hypocentral depth, rupture direction, rupture length and width. We illustrate the advantages of this approach by case

  3. Stockpile Stewardship: Los Alamos

    SciTech Connect

    McMillan, Charlie; Morgan, Nathanial; Goorley, Tom; Merrill, Frank; Funk, Dave; Korzekwa, Deniece; Laintz, Ken

    2012-01-26

    "Heritage of Science" is a short video that highlights the Stockpile Stewardship program at Los Alamos National Laboratory. Stockpile Stewardship was conceived in the early 1990s as a national science-based program that could assure the safety, security, and effectiveness of the U.S. nuclear deterrent without the need for full-scale underground nuclear testing. This video was produced by Los Alamos National Laboratory for screening at the Lab's Bradbury Science Museum in Los Alamos, NM and is narrated by science correspondent Miles O'Brien.

  4. Stockpile Stewardship: Los Alamos

    ScienceCinema

    McMillan, Charlie; Morgan, Nathanial; Goorley, Tom; Merrill, Frank; Funk, Dave; Korzekwa, Deniece; Laintz, Ken

    2014-08-12

    "Heritage of Science" is a short video that highlights the Stockpile Stewardship program at Los Alamos National Laboratory. Stockpile Stewardship was conceived in the early 1990s as a national science-based program that could assure the safety, security, and effectiveness of the U.S. nuclear deterrent without the need for full-scale underground nuclear testing. This video was produced by Los Alamos National Laboratory for screening at the Lab's Bradbury Science Museum in Los Alamos, NM and is narrated by science correspondent Miles O'Brien.

  5. Potential improvements in horizontal very broadband seismic data in the IRIS/USGS component of the Global Seismic Network

    USGS Publications Warehouse

    Ringler, Adam; Steim, J.M.; Zandt, T; Hutt, Charles R.; Wilson, David; Storm, Tyler

    2016-01-01

    The Streckeisen STS‐1 has been the primary vault‐type seismometer used in the over‐150‐station Global Seismographic Network (GSN). This sensor has long been known for its outstanding vertical, very long‐period (e.g., >100  s period), and low‐noise performance, although the horizontal long‐period noise performance is less well known. The STS‐1 is a limited, important resource, because it is no longer made or supported by the original manufacturer. We investigate the incoherent noise of horizontal‐component sensors, where coherent signals among sensors have been removed, giving an upper bound on the self‐noise of both the STS‐1 and STS‐2 horizontal components. Our findings suggest that a well‐installed STS‐2 could potentially produce data with similar or better incoherent noise levels to that of a horizontal‐component STS‐1. Along with our experimental investigation, we compare background noise levels for a calendar year at Incorporated Research Institutions for Seismology/U.S. Geological Survey network stations, which comprise approximately two‐thirds of the GSN, with collocated STS‐1 and STS‐2 seismometers. The use of an STS‐2‐class of sensor (flat to velocity to 120 s period) to acquire low‐frequency data in surface‐vault installations would allow network operators to focus more attention on improving vertical data. In order to deal with the difference in instrument response shapes between the two instruments, we detail two different time‐domain filters that would allow users to convert broadband STS‐2 data into very broadband data with a response similar to that of an STS‐1 (flat to velocity to 360 s period). We conclude that the complexity of the current primary horizontal vault sensors in the GSN may not be necessary until we are better able to isolate surface horizontal sensors from various noise sources.

  6. Teacher Directed Design: Content Knowledge, Pedagogy and Assessment under the Nevada K-12 Real-Time Seismic Network

    NASA Astrophysics Data System (ADS)

    Cantrell, P.; Ewing-Taylor, J.; Crippen, K. J.; Smith, K. D.; Snelson, C. M.

    2004-12-01

    Education professionals and seismologists under the emerging SUN (Shaking Up Nevada) program are leveraging the existing infrastructure of the real-time Nevada K-12 Seismic Network to provide a unique inquiry based science experience for teachers. The concept and effort are driven by teacher needs and emphasize rigorous content knowledge acquisition coupled with the translation of that knowledge into an integrated seismology based earth sciences curriculum development process. We are developing a pedagogical framework, graduate level coursework, and materials to initiate the SUN model for teacher professional development in an effort to integrate the research benefits of real-time seismic data with science education needs in Nevada. A component of SUN is to evaluate teacher acquisition of qualified seismological and earth science information and pedagogy both in workshops and in the classroom and to assess the impact on student achievement. SUN's mission is to positively impact earth science education practices. With the upcoming EarthScope initiative, the program is timely and will incorporate EarthScope real-time seismic data (USArray) and educational materials in graduate course materials and teacher development programs. A number of schools in Nevada are contributing real-time data from both inexpensive and high-quality seismographs that are integrated with Nevada regional seismic network operations as well as the IRIS DMC. A powerful and unique component of the Nevada technology model is that schools can receive "stable" continuous live data feeds from 100's seismograph stations in Nevada, California and world (including live data from Earthworm systems and the IRIS DMC BUD - Buffer of Uniform Data). Students and teachers see their own networked seismograph station within a global context, as participants in regional and global monitoring. The robust real-time Internet communications protocols invoked in the Nevada network provide for local data acquisition

  7. Operation of a digital seismic network on Mount St. Helens volcano and observations of long-period seismic events that originate under the volcano

    SciTech Connect

    Fehler, M.; Chouet, B.

    1982-01-01

    During the period May through October 1981, a nine station digital seismic array was operated on the flanks of Mount St. Helens volcano in the state of Washington. The purpose was to obtain high quality digital seismic data from a dense seismic array operating near and in the summit crater of the volcano to facilitate study of near field seismic waveforms generated under the volcano. Our goal is to investigate the source mechanism of volcanic tremor and seismic activity associated with magma intrusion, dome growth and steam-ash emissions occurring within the crater of Mount St. Helens.

  8. Evidence of magma intrusion at Fourpeaked volcano, Alaska in 2006-2007 from a rapid-response seismic network and volcanic gases

    USGS Publications Warehouse

    Gardine, M.; West, M.; Werner, C.; Doukas, M.

    2011-01-01

    On September 17th, 2006, Fourpeaked volcano had a widely-observed phreatic eruption. At the time, Fourpeaked was an unmonitored volcano with no known Holocene activity, based on limited field work. Airborne gas sampling began within days of the eruption and a modest seismic network was installed in stages. Vigorous steaming continued for months; however, there were no further eruptions similar in scale to the September 17 event. This eruption was followed by several months of sustained seismicity punctuated by vigorous swarms, and SO2 emissions exceeding a thousand tons/day. Based on observations during and after the phreatic eruption, and assuming no recent pre-historical eruptive activity at Fourpeaked, we propose that the activity was caused by a minor injection of new magma at or near 5km depth beneath Fourpeaked, which remained active over several months as this magma equilibrated into the crust. By early 2007 declining seismicity and SO2 emission signaled the end of unrest. Because the Fourpeaked seismic network was installed in stages and the seismicity was punctuated by discrete swarms, we use Fourpeaked to illustrate quantitatively the efficacy and shortcomings of rapid response seismic networks for tracking volcanic earthquakes.

  9. Evidence of magma intrusion at Fourpeaked volcano, Alaska in 2006-2007 from a rapid-response seismic network and volcanic gases

    NASA Astrophysics Data System (ADS)

    Gardine, Matt; West, Michael; Werner, Cynthia; Doukas, Michael

    2011-03-01

    On September 17th, 2006, Fourpeaked volcano had a widely-observed phreatic eruption. At the time, Fourpeaked was an unmonitored volcano with no known Holocene activity, based on limited field work. Airborne gas sampling began within days of the eruption and a modest seismic network was installed in stages. Vigorous steaming continued for months; however, there were no further eruptions similar in scale to the September 17 event. This eruption was followed by several months of sustained seismicity punctuated by vigorous swarms, and SO 2 emissions exceeding a thousand tons/day. Based on observations during and after the phreatic eruption, and assuming no recent pre-historical eruptive activity at Fourpeaked, we propose that the activity was caused by a minor injection of new magma at or near 5 km depth beneath Fourpeaked, which remained active over several months as this magma equilibrated into the crust. By early 2007 declining seismicity and SO 2 emission signaled the end of unrest. Because the Fourpeaked seismic network was installed in stages and the seismicity was punctuated by discrete swarms, we use Fourpeaked to illustrate quantitatively the efficacy and shortcomings of rapid response seismic networks for tracking volcanic earthquakes.

  10. Seismology on the Greenland ice sheet: results from the deployment of a high-density campaign seismic network in 2011

    NASA Astrophysics Data System (ADS)

    Walter, F.; Husen, S.; Meier, M.; Plenkers, K.; Hiemer, S.; Ryser, C.; Lüthi, M.; Funk, M.; Catania, G.; Clinton, J.

    2012-04-01

    The effect of the observed increase in surface melt on the dynamics of the Greenland ice sheet is not fully understood. Specifically, it is not clear to what extent the subglacial hydraulic system can respond to changes in melt water input. Depending on its adaptability, the subglacial drainage system may help enhance or diminish ice flow during warming air temperatures. In order to gain a better understanding of the subglacial drainage system, we installed a high-density campaign seismic network during summer 2011 on the Greenland ice sheet. The goal of the passive seismic monitoring is the detection and characterization of dislocation mechanisms, such as englacial fracturing and basal stick-slip motion. A better understanding of these processes will elucidate the englacial and subglacial drainage system and its role in ice dynamics. The seismic deployment was part of an international deep drilling project. In the vicinity of the seismic network seven boreholes were drilled to the glacier bed and equipped with scientific instruments to measure englacial deformation, temperature, basal water pressure and glacier sliding rates. In our presentation we describe the seismological experiment and offer a first impression of the 'icequake' waveform variety, which we have recorded. The installation consisted of 17 three-component seismometers, including three deep (150 - 400 m) borehole sensors and two broadband seismometers. The aperture of the array was about one kilometre. It was operated over a time span of six weeks. Data were recorded continuously at high sampling frequencies (500 Hz). Due to high ablation rates surface sensors had to be re-leveled daily. As expected from previous studies of Alpine icequakes we recorded a large number of surface crevassing events and found evidence for deeper (more than 100 m depth) fracture events most likely due englacial hydrofracturing. In addition, we recorded relatively low-frequency (0.3-1.5 Hz) transients, with high signal

  11. Using the Internet in Middle Schools: A Model for Success. A Collaborative Effort between Los Alamos National Laboratory (LANL) and Los Alamos Middle School (LAMS).

    ERIC Educational Resources Information Center

    Addessio, Barbara K.; And Others

    Los Alamos National Laboratory (LANL) developed a model for school networking using Los Alamos Middle School as a testbed. The project was a collaborative effort between the school and the laboratory. The school secured administrative funding for hardware and software; and LANL provided the network architecture, installation, consulting, and…

  12. Active normal fault network of the Apulian Ridge (Eastern Mediterranean Sea) imaged by multibeam bathymetry and seismic data

    NASA Astrophysics Data System (ADS)

    Pellegrini, Claudio; Marchese, Fabio; Savini, Alessandra; Bistacchi, Andrea

    2016-04-01

    The Apulian ridge (North-eastern Ionian margin - Mediterranean Sea) is formed by thick cretaceous carbonatic sequences and discontinuous tertiary deposits crosscut by a NNW-SSE penetrative normal fault system and is part of the present foreland system of both the Apennine to the west and the Hellenic arc to the east. The geometry, age, architecture and kinematics of the fault network were investigated integrating data of heterogeneous sources, provided by previous studies: regional scale 2D seismics and three wells collected by oil companies from the '60s to the '80s, more recent seismics collected during research projects in the '90s, very high resolution seismic (VHRS - Sparker and Chirp-sonar data), multi-beam echosounder bathymetry and results from sedimentological and geo-chronological analysis of sediment samples collected on the seabed. Multibeam bathymetric data allowed in particular assessing the 3D continuity of structures imaged in 2D seismics, thanks to the occurrence of continuous fault scarps on the seabed (only partly reworked by currents and covered by landslides), revealing the vertical extent and finite displacement associated to fault scarps. A penetrative network of relatively small faults, always showing a high dip angle, composes the NNW-SSE normal fault system, resulting in frequent relay zones, which are particularly well imaged by seafloor geomorphology. In addition, numerous fault scarps appear to be roughly coeval with quaternary submarine mass-wasting deposits colonised by Cold-Water Corals (CWC). Coral colonies, yielding ages between 11 and 14 kA, develop immediately on top of late Pleistocene mass-wasting deposits. Mutual cross-cutting relationships have been recognized between fault scarps and landslides, indicating that, at least in places, these features may be coeval. We suppose that fault activity lasted at least as far as the Holocene-Pleistocene boundary and that the NNW-SSW normal fault network in the Apulian Plateau can be

  13. Performance of the primary seismic array stations of the IMS network for the year 2015 Part II): An Analyst's perspective

    NASA Astrophysics Data System (ADS)

    Jonathan, Ezekiel; Kebede, Fekadu

    2016-04-01

    Verification of the CTBT is partly dependent on the ability of the automatic system to detect and present correct attributes for all phases that are detected at the stations. This helps in building of more accurate automatic event solutions and thus reducing the work load and time for interactive analysis whilst increasing the quality of bulletins issued out to member states so that they can decide if there are any treaty violations. During interactive analysis automatic event solutions are refined and/or re-estimated by checking the correctness of the associated phase identity, phase arrival time, azimuth and slowness using raw waveform data. This refinement procedure leads analysts to rename, associate, disassociate and manually add seismic arrivals. The final event solution is accepted or rejected based on the existing rules, guidelines and procedures. In addition, new event solutions are built using unassociated signal detections and the raw waveform data during scanning. In this study differences between seismic phases associated to automatically produced SEL3 bulletin and the Late Event Bulletin (LEB) obtained through interactive analysis are investigated using data from all primary seismic array stations of the International Monitoring System (IMS) network during the year 2015. The performance of the network is evaluated from an analyst's perspective by looking at the number of phases that are renamed, manually added, associated, and disassociated by analysts during interactive analysis. The observed differences do shed some light on analysts workload as well as the performance of the primary seismic array of the IMS network. For example, the results indicate that for the Waramunga array station in Australia (WRA) out of a total of 41175 detections associated to saved events in 2015, 13305 (32.3%) of them were renamed during interactive analysis and 7667 were automatic detections that were associated to events by analysts. 1174 detections were manually added

  14. Hydraulic fracturing and the Crooked Lake Sequences: Insights gleaned from regional seismic networks

    NASA Astrophysics Data System (ADS)

    Schultz, Ryan; Stern, Virginia; Novakovic, Mark; Atkinson, Gail; Gu, Yu Jeffrey

    2015-04-01

    Within central Alberta, Canada, a new sequence of earthquakes has been recognized as of 1 December 2013 in a region of previous seismic quiescence near Crooked Lake, ~30 km west of the town of Fox Creek. We utilize a cross-correlation detection algorithm to detect more than 160 events to the end of 2014, which is temporally distinguished into five subsequences. This observation is corroborated by the uniqueness of waveforms clustered by subsequence. The Crooked Lake Sequences have come under scrutiny due to its strong temporal correlation (>99.99%) to the timing of hydraulic fracturing operations in the Duvernay Formation. We assert that individual subsequences are related to fracturing stimulation and, despite adverse initial station geometry, double-difference techniques allow us to spatially relate each cluster back to a unique horizontal well. Overall, we find that seismicity in the Crooked Lake Sequences is consistent with first-order observations of hydraulic fracturing induced seismicity.

  15. The application of back-propagation neural network to automatic picking seismic arrivals from single-component recordings

    NASA Astrophysics Data System (ADS)

    Dai, Hengchang; MacBeth, Colin

    1997-07-01

    An automatic approach is developed to pick P and S arrivals from single component (1-C) recordings of local earthquake data. In this approach a back propagation neural network (BPNN) accepts a normalized segment (window of 40 samples) of absolute amplitudes from the 1-C recordings as its input pattern, calculating two output values between 0 and 1. The outputs (0,1) or (1,0) correspond to the presence of an arrival or background noise within a moving window. The two outputs form a time series. The P and S arrivals are then retrieved from this series by using a threshold and a local maximum rule. The BPNN is trained by only 10 pairs of P arrivals and background noise segments from the vertical component (V-C) recordings. It can also successfully pick seismic arrivals from the horizontal components (E-W and N-S). Its performance is different for each of the three components due to strong effects of ray path and source position on the seismic waveforms. For the data from two stations of TDP3 seismic network, the success rates are 93%, 89%, and 83% for P arrivals and 75%, 91%, and 87% for S arrivals from the V-C, E-W, and N-S recordings, respectively. The accuracy of the onset times picked from each individual 1-C recording is similar. Adding a constraint on the error to be 10 ms (one sample increment), 66%, 59% and 63% of the P arrivals and 53%, 61%, and 58% of the S arrivals are picked from the V-C, E-W and N-S recordings respectively. Its performance is lower than a similar three-component picking approach but higher than other 1-C picking methods.

  16. Artificial Neural Networks applied to estimate permeability, porosity and intrinsic attenuation using seismic attributes and well-log data

    NASA Astrophysics Data System (ADS)

    Iturrarán-Viveros, Ursula; Parra, Jorge O.

    2014-08-01

    Permeability and porosity are two fundamental reservoir properties which relate to the amount of fluid contained in a reservoir and its ability to flow. The intrinsic attenuation is another important parameter since it is related to porosity, permeability, oil and gas saturation and these parameters significantly affect the seismic signature of a reservoir. We apply Artificial Neural Network (ANN) models to predict permeability (k) and porosity (ϕ) for a carbonate aquifer in southeastern Florida and to predict intrinsic attenuation (1/Q) for a sand-shale oil reservoir in northeast Texas. In this study, the Gamma test (a revolutionary estimator of the noise in a data set) has been used as a mathematically non-parametric nonlinear smooth modeling tool to choose the best input combination of seismic attributes to estimate k and ϕ, and the best combination of well-logs to estimate 1/Q. This saves time during the construction and training of ANN models and also sets a lower bound for the mean squared error to prevent over-training. The Neural Network method successfully delineates a highly permeable zone that corresponds to a high water production in the aquifer. The Gamma test found nonlinear relations that were not visible to linear regression allowing us to generalize the ANN estimations of k, ϕ and 1/Q for their respective sets of patterns that were not used during the learning phase.

  17. Improvements of the Regional Seismic network of Northwestern Italy in the framework of ALCoTra program activities

    NASA Astrophysics Data System (ADS)

    Bosco, Fabrizio

    2014-05-01

    Arpa Piemonte (Regional Agency for Environmental Protection), in partnership with University of Genoa, manages the regional seismic network, which is part of the Regional Seismic network of Northwestern Italy (RSNI). The network operates since the 80s and, over the years, it has developed in technological features, analysis procedures and geographical coverage. In particular in recent years the network has been further enhanced through the integration of Swiss and French stations installed in the cross-border area. The environmental context enables the installation of sensors in sites with good conditions as regards ambient noise and limited local amplification effects (as proved by PSD analysis, signal quality monitoring via PQLX, H/V analysis). The instrumental equipment consists of Broadband and Very Broadband sensors (Nanometrics Trillium 40" and 240") and different technological solutions for signals real-time transmission (cable, satellite, GPRS), according to the different local environment, with redundant connections and with experimental innovative systems. Digital transmission and acquisition systems operate through standard protocols (Nanometrics, SeedLink), with redundancy in data centers (Genoa, Turin, Rome). Both real-time automatic and manual operational procedures are in use for signals analysis (events detection, picking, focal parameters and ground shaking determination). In the framework of cross-border cooperation program ALCoTra (http://www.interreg-alcotra.org), approved by the European Commission, several projects have been developed to improve the performances of seismic monitoring systems used by partners (Arpa Piemonte, Aosta Valley Region, CNRS, Joseph Fourier University). The cross-border context points out first of all the importance of signals sharing (from 14 to 23 stations in narrow French-Italian border area, with an increase of over 50%) and of coordination during new stations planning and installation in the area. In the ongoing

  18. The Seismic Broad Band Western Mediterranean (wm) Network and the Obs Fomar Pool: Current state and Obs activities.

    NASA Astrophysics Data System (ADS)

    Pazos, Antonio; Davila, Jose Martin; Buforn, Elisa; Bezzeghoud, Mourad; Harnafi, Mimoun; Mattesini, Mauricio; Caldeira, Bento; Hanka, Winfried; El Moudnib, Lahcen; Strollo, Angelo; Roca, Antoni; Lopez de Mesa, Mireya; Dahm, Torsten; Cabieces, Roberto

    2016-04-01

    The Western Mediterranean (WM) seismic network started in 1996 as an initiative of the Royal Spanish Navy Observatory (ROA) and the Universidad Complutense de Madrid (UCM), with the collaboration of the GeoForschungsZentrum (GFZ) of Potsdam. A first broad band seismic station (SFUC) was installed close to Cádiz (South Spain). Since then, additional stations have been installed in the Ibero-Moghrebian region. In 2005, the "WM" code was assigned by the FDSN and new partners were jointed: Evora University (UEVO, Portugal), the Scientifique Institute of Rabat (ISRABAT, Morocco), and GFZ. Now days, the WM network is composed by 15 BB stations, all of them with Streckaisen STS-2 or STS-2.5 sensors, Quanterra or Earthdata digitizers and SeiscomP. Most them have co-installed a permanent geodetic GPS stations, and some them also have an accelerometer. There are 10 stations deployed in Spanish territory (5 in the Iberian peninsula, 1 in Balearic islands and 4 in North Africa Spanish places) with VSAT or Internet communications, 2 in Portugal (one of them without real time), and 3 in Morocco (2 VSAT and 1 ADSL). Additionally, 2 more stations (one in South Spain and one in Morocco) will be installed along this year. Additionally ROA has deployed a permanent real time VBB (CMG-3T: 360s) station at the Alboran Island. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), ROA and UCM have acquired six broad band "LOBSTERN" OBS, manufactured by KUM (Kiel, Germany), conforming the OBS FOMAR pool. Three of them with CMG-40T sensor and the other with Trillium 120. These OBS were deployed along the Gibraltar strait since January to November 2014 to study the microseismicity in the Gibraltar strait area. In September 2015 FOMAR network has been deployed in SW of the San Vicente Cape for 8 months as a part of

  19. Los Alamos offers Fellowships

    NASA Astrophysics Data System (ADS)

    Los Alamos National Laboratory in New Mexico is calling for applications for postdoctoral appointments and research fellowships. The positions are available in geoscience as well as other scientific disciplines.The laboratory, which is operated by the University of California for the Department of Energy, awards J. Robert Oppenheimer Research Fellowships to scientists that either have or will soon complete doctoral degrees. The appointments are for two years, are renewable for a third year, and carry a stipend of $51,865 per year. Potential applicants should send a resume or employment application and a statement of research goals to Carol M. Rich, Div. 89, Human Resources Development Division, MS P290, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 by mid-November.

  20. Bedrock mapping of buried valley networks using seismic reflection and airborne electromagnetic data

    NASA Astrophysics Data System (ADS)

    Oldenborger, G. A.; Logan, C. E.; Hinton, M. J.; Pugin, A. J.-M.; Sapia, V.; Sharpe, D. R.; Russell, H. A. J.

    2016-05-01

    In glaciated terrain, buried valleys often host aquifers that are significant groundwater resources. However, given the range of scales, spatial complexity and depth of burial, buried valleys often remain undetected or insufficiently mapped. Accurate and thorough mapping of bedrock topography is a crucial step in detecting and delineating buried valleys and understanding formative valley processes. We develop a bedrock mapping procedure supported by the combination of seismic reflection data and helicopter time-domain electromagnetic data with water well records for the Spiritwood buried valley aquifer system in Manitoba, Canada. The limited spatial density of water well bedrock observations precludes complete depiction of the buried valley bedrock topography and renders the water well records alone inadequate for accurate hydrogeological model building. Instead, we leverage the complementary strengths of seismic reflection and airborne electromagnetic data for accurate local detection of the sediment-bedrock interface and for spatially extensive coverage, respectively. Seismic reflection data are used to define buried valley morphology in cross-section beneath survey lines distributed over a regional area. A 3D model of electrical conductivity is derived from inversion of the airborne electromagnetic data and used to extrapolate buried valley morphology over the entire survey area. A spatially variable assignment of the electrical conductivity at the bedrock surface is applied to different features of the buried valley morphology identified in the seismic cross-sections. Electrical conductivity is then used to guide construction of buried valley shapes between seismic sections. The 3D locus of points defining each morphological valley feature is constructed using a path optimization routine that utilizes deviation from the assigned electrical conductivities as the cost function. Our resulting map represents a bedrock surface of unprecedented detail with more

  1. Neural network analysis of crosshole tomographic images: The seismic signature of gas hydrate bearing sediments in the Mackenzie Delta (NW Canada)

    NASA Astrophysics Data System (ADS)

    Bauer, K.; Pratt, R. G.; Haberland, C.; Weber, M.

    2008-10-01

    Crosshole seismic experiments were conducted to study the in-situ properties of gas hydrate bearing sediments (GHBS) in the Mackenzie Delta (NW Canada). Seismic tomography provided images of P velocity, anisotropy, and attenuation. Self-organizing maps (SOM) are powerful neural network techniques to classify and interpret multi-attribute data sets. The coincident tomographic images are translated to a set of data vectors in order to train a Kohonen layer. The total gradient of the model vectors is determined for the trained SOM and a watershed segmentation algorithm is used to visualize and map the lithological clusters with well-defined seismic signatures. Application to the Mallik data reveals four major litho-types: (1) GHBS, (2) sands, (3) shale/coal interlayering, and (4) silt. The signature of seismic P wave characteristics distinguished for the GHBS (high velocities, strong anisotropy and attenuation) is new and can be used for new exploration strategies to map and quantify gas hydrates.

  2. Regional seismic event identification and improved locations with small arrays and networks. Final report, 7 May 1993-30 September 1995

    SciTech Connect

    Vernon, F.L.; Minster, J.B.; Orcutt, J.A.

    1995-09-20

    This final report contains a summary of our work on the use of seismic networks and arrays to improve locations and identify small seismic event. We have developed techniques to migrate 3-component array records of local, regional and teleseismic wavetrains to directly image buried two- and three-dimensional heterogeneities (e.g. layer irregularities, volumetric heterogeneities) in the vicinity of the array. We have developed a technique to empirically characterize local and regional seismic code by binning and stacking network recordings of dense aftershock sequences. The principle motivation for this work was to look for robust coda phases dependent on source depth. We have extended our ripple-fired event discriminant (based on the time-independence of coda produced by ripple firing) by looking for an independence of the coda from the recording direction (also indicative of ripple-firing).

  3. The Los Alamos primer

    SciTech Connect

    Serber, R.

    1992-01-01

    This book contains the 1943 lecture notes of Robert Serber. Serber was a protege of J. Robert Oppenheimer and member of the team that built the first atomic bomb - reveal what the Los Alamos scientists knew, and did not know, about the terrifying weapon they were building.

  4. Anisotropy of the Earth's inner inner core from autocorrelations of earthquake coda in China Regional Seismic Networks

    NASA Astrophysics Data System (ADS)

    Xia, H.; Song, X.; Wang, T.

    2014-12-01

    The Earth's inner core possesses strong cylindrical anisotropy with the fast symmetry axis parallel to the rotation axis. However, recent study has suggested that the inner part of the inner core has a fast symmetry axis near the equator with a different form of anisotropy from the outer part (Wang et al., this session). To confirm the observation, we use data from dense seismic arrays of the China Regional Seismic Networks. We perform autocorrelation (ACC) of the coda after major earthquakes (Mw>=7.0) at each station and then stack the ACCs at each cluster of stations. The PKIKP2 and PKIIKP2 phases (round-trip phase from the Earth's surface reflections) can be clearly extracted from the stacked empirical Green's functions. We observe systematic variation of the differential times between PKIKP2 and PKIIKP2 phases, which are sensitive to the bulk anisotropy of the inner core. The differential times show large variations with both latitudes and longitudes, even though our ray paths are not polar (with our stations at mid-range latitudes of about 20 to 45 degrees). The observations cannot be explained by an averaged anisotropy model with the fast axis along the rotation axis. The pattern appears consistent with an inner inner core that has a fast axis near the equator.

  5. High-rate real-time GPS network at Parkfield: Utility for detecting fault slip and seismic displacements

    USGS Publications Warehouse

    Langbein, J.; Bock, Y.

    2004-01-01

    A network of 13 continuous GPS stations near Parkfield, California has been converted from 30 second to 1 second sampling with positions of the stations estimated in real-time relative to a master station. Most stations are near the trace of the San Andreas fault, which exhibits creep. The noise spectra of the instantaneous 1 Hz positions show flicker noise at high frequencies and change to frequency independence at low frequencies; the change in character occurs between 6 to 8 hours. Our analysis indicates that 1-second sampled GPS can estimate horizontal displacements of order 6 mm at the 99% confidence level from a few seconds to a few hours. High frequency GPS can augment existing measurements in capturing large creep events and postseismic slip that would exceed the range of existing creepmeters, and can detect large seismic displacements. Copyright 2004 by the American Geophysical Union.

  6. Characterization of the seismicity in the Gulf of Cadiz based on eleven month monitoring by the NEAREST OBS network

    NASA Astrophysics Data System (ADS)

    Silva, S.; Romsdorf, M.; Matias, L.; Geissler, W. H.; Terrinha, P.; Carrilho, F.; Nearest Working-Group

    2010-05-01

    The Gulf of Cadiz offshore SW Iberia is an area that is prone to the generation of destructive earthquakes and tsunamis, like the famous 1st November 1755 Lisbon event. A considerable effort from many international teams allowed the recognition of the main active geological structures that may generate large earthquakes. However, the relationship between the frequent small magnitude events and the geological structures have been elusive so far due mostly to the unfavourable geometry of the seismic network based on land stations that does not allow a precise hypocentre location. To address this problem the EC project NEAREST (Integrated observation from NEAR shore sourcES of Tsunamis: towards an early warning system) conducted a passive seismic experiment in the Gulf of Cadiz where 24 BB seismometers (plus the GEOSTAR multi-parameter deep-sea observatory) were deployed for 11 months, between the summer 2007 and summer 2008. The careful examination of the continuous data stream allowed the detection of a large number of local events that were not detected by the land networks of Portugal, Spain or Morocco. The analysis of the complete data set reveals 3 main clusters of earthquakes that coincide with the location of the 3 larger instrumental earthquakes in the area: i) the 28th February 1969 (Mw~8.0); ii) the 12th February 2007 (Mw=6.0) and iii) the 17th December 2009 (ML=6.0). Many of the small magnitude earthquakes are located in the mantle (depth between 30 and 60 km), like the hypocenters of these three earthquakes derived from waveform inversion. However, not a single structure is active in each cluster area since focal mechanisms show a mixed pattern, mostly strike-slip and reverse dip-slip with a very few normal mechanisms.

  7. Analysis of Modern Techniques for Nuclear-test Yield Determination of NTS Events Using Data From the Leo Brady Seismic Network

    NASA Astrophysics Data System (ADS)

    Schramm, K. A.; Bilek, S. L.; Abbott, R. E.

    2007-12-01

    Nuclear test detection is a challenging, but important task for treaty verification. Many techniques have been developed to discriminate between an explosion and an earthquake and if an explosion is detected, to determine its yield. Sandia National Laboratories (SNL) has maintained the Leo Brady Seismic Network (LBSN) since 1960 to record nuclear tests at the Nevada Test Site (NTS), providing a unique data set for yield determination. The LBSN is comprised of five permanent stations surrounding the NTS at regional distances, and data (in digital from post 1983) exists for almost all tests. Modern seismic data processing techniques can be used with this data to apply new methods to better determine the seismic yield. Using mb(Lg) we found that, when compared to published yields, our estimates were low for events over 100 kilotons (kt) and near the published value for events under 40 kt. We are currently measuring seismic-phase amplitudes, examining body- and surface-wave spectra and using seismic waveform modeling techniques to determine the seismic yield of NTS explosions using the waveforms from the LBSN.

  8. Seismic source and structure estimation in the western Mediterranean using a sparse broadband network

    NASA Astrophysics Data System (ADS)

    Thio, Hong Kie; Song, Xi; Saikia, Chandan K.; Helmberger, Donald V.; Woods, Bradley B.

    1999-01-01

    We present a study of regional earthquakes in the western Mediterranean geared toward the development of methodologies and path calibrations for source characterization using regional broadband stations. The results of this study are useful for the monitoring and discrimination of seismic events under a comprehensive test ban treaty, as well as the routine analysis of seismicity and seismic hazard using a sparse array of stations. The area consists of several contrasting geological provinces with distinct seismic properties, which complicates the modeling of seismic wave propagation. We started by analyzing surface wave group velocities throughout the region and developed a preliminary model for each of the major geological provinces. We found variations of crustal thickness ranging from 45 km under the Atlas and Betic mountains and 37 km under the Saharan shield, to 20 km for the oceanic crust of the western Mediterranean Sea, which is consistent with earlier works. Throughout most of the region, the upper mantle velocities are low which is typical for tectonically active regions. The most complex areas in terms of wave propagation are the Betic Cordillera in southern Spain and its north African counterparts, the Rif and Tell Atlas mountains, as well as the Alboran Sea, between Spain and Morocco. The complexity of the wave propagation in these regions is probably due to the sharp velocity contrasts between the oceanic and continental regions as well as the the existence of deep sedimentary basins that have a very strong influence on the surface wave dispersion. We used this preliminary regionalized velocity model to correct the surface wave source spectra for propagation effects which we then inverted for source mechanism. We found that this method, which is in use in many parts of the world, works very well, provided that data from several stations are available. In order to study the events in the region using very few broadband stations or even a single station

  9. Present and Future of Metropolitan Seismic Observation network (MeSO-net) in Japan

    NASA Astrophysics Data System (ADS)

    Hirata, N.; Nakagawa, S.; Sakai, S.; Honda, R.; Kimura, H.; Panayotopoulos, Y.; Kano, M.

    2015-12-01

    Tokyo and its vicinity are most seismically risky areas in the world. To prepare for the seismic disaster we have started a series of integrated Tokyo Metropolitan projects for disaster mitigation since 2002.The current Tokyo Metropolitan Project (Phase III) has started in 2012 with a new project name as "Special Project for Reducing Vulnerability for Urban Mega-earthquake Disasters" to use MeSO-net data for constructing 3-D velocity and Q structure beneath the greater Tokyo. We aim to collect data for regional characterization to access seismic hazard produced by subduction of Philippine Sea and Pacific plates. The data from MeSO-net are continuously collected at the data management center in the Earthquake Research Institute (ERI), the University of Tokyo, with a sampling rate of 200 Hz. The data are 3-componnent accelerogram with a full scale of +/- 1,500 gal for horizontal and +/-500 gal for vertical component and the effective dynamic range is 135dB at 40Hz. Available frequency range is from 0.05 to 85 Hz, which is good for travel time analysis of body waves to ambient noise analysis for surface waves. We have successfully operated MeSO-net for about 7 years without serious malfunction. We collect more than 150 TB continuous ground motion data with more than 100K earthquakes including the 2011 Tohoku-oki earthquake and all its aftershocks. The data are used many studies (e.g., Nakagawa et al., 2010,2015; Ishibe et al., 2015; Denolle et al., 2014) and currently prepared for disclosing both in continues and event-by-event format. We are developing a fully automatic earthquake detection/location system for local earthquakes beneath MeSO-net. A numerical system to estimate ground motions at an arbitrary location without MeSO-net station is under developing (Kano et al., 2015).We also install a sensor system in a building for monitoring motion and damages by a large earthquake (Nakashima et al., 2015). Those studies are eventually integrated to develop an advanced

  10. Design and development of safety evaluation system of buildings on a seismic field based on the network platform

    NASA Astrophysics Data System (ADS)

    Sun, Baitao; Zhang, Lei; Chen, Xiangzhao; Zhang, Xinghua

    2015-03-01

    This paper describes a set of on-site earthquake safety evaluation systems for buildings, which were developed based on a network platform. The system embedded into the quantitative research results which were completed in accordance with the provisions from Post-earthquake Field Works, Part 2: Safety Assessment of Buildings, GB18208.2 -2001, and was further developed into an easy-to-use software platform. The system is aimed at allowing engineering professionals, civil engineeing technicists or earthquake-affected victims on site to assess damaged buildings through a network after earthquakes. The authors studied the function structure, process design of the safety evaluation module, and hierarchical analysis algorithm module of the system in depth, and developed the general architecture design, development technology and database design of the system. Technologies such as hierarchical architecture design and Java EE were used in the system development, and MySQL5 was adopted in the database development. The result is a complete evaluation process of information collection, safety evaluation, and output of damage and safety degrees, as well as query and statistical analysis of identified buildings. The system can play a positive role in sharing expert post-earthquake experience and promoting safety evaluation of buildings on a seismic field.

  11. Products and Services Available from the Southern California Earthquake Data Center (SCEDC) and the Southern California Seismic Network (SCSN)

    NASA Astrophysics Data System (ADS)

    Yu, E.; Bhaskaran, A.; Chen, S.; Chowdhury, F. R.; Meisenhelter, S.; Hutton, K.; Given, D.; Hauksson, E.; Clayton, R. W.

    2010-12-01

    Currently the SCEDC archives continuous and triggered data from nearly 5000 data channels from 425 SCSN recorded stations, processing and archiving an average of 12,000 earthquakes each year. The SCEDC provides public access to these earthquake parametric and waveform data through its website www.data.scec.org and through client applications such as STP and DHI. This poster will describe the most significant developments at the SCEDC in the past year. Updated hardware: ● The SCEDC has more than doubled its waveform file storage capacity by migrating to 2 TB disks. New data holdings: ● Waveform data: Beginning Jan 1, 2010 the SCEDC began continuously archiving all high-sample-rate strong-motion channels. All seismic channels recorded by SCSN are now continuously archived and available at SCEDC. ● Portable data from El Mayor Cucapah 7.2 sequence: Seismic waveforms from portable stations installed by researchers (contributed by Elizabeth Cochran, Jamie Steidl, and Octavio Lazaro-Mancilla) have been added to the archive and are accessible through STP either as continuous data or associated with events in the SCEDC earthquake catalog. This additional data will help SCSN analysts and researchers improve event locations from the sequence. ● Real time GPS solutions from El Mayor Cucapah 7.2 event: Three component 1Hz seismograms of California Real Time Network (CRTN) GPS stations, from the April 4, 2010, magnitude 7.2 El Mayor-Cucapah earthquake are available in SAC format at the SCEDC. These time series were created by Brendan Crowell, Yehuda Bock, the project PI, and Mindy Squibb at SOPAC using data from the CRTN. The El Mayor-Cucapah earthquake demonstrated definitively the power of real-time high-rate GPS data: they measure dynamic displacements directly, they do not clip and they are also able to detect the permanent (coseismic) surface deformation. ● Triggered data from the Quake Catcher Network (QCN) and Community Seismic Network (CSN): The SCEDC in

  12. The ROBEX-ASN - A Concept Study for an active seismic Network on the Moon

    NASA Astrophysics Data System (ADS)

    Czeluschke, A.; Knapmeyer, M.; Sohl, F.; Bamberg, M.; Lange, C.; Luther, R.; Margonis, A.; Rosta, R.; Schmitz, N.; Robex Asn Study Team

    2014-04-01

    The Helmholtz Alliance "Robotic Exploration of Extreme Environments - ROBEX", brings together space and deep-sea researchers. The project partners are jointly developing technologies for the exploration of highly inaccessible terrains. The research on the Moon and in the deep sea would answer different scientific questions but should be addressed by a common method (seismic surveys) and technological solution. The overall goal is to develop a combination of a stationary system and one or more mobile elements. The stationary system would provide the energy supply and the possibility to exchange data between the elements and the ground station. The mobile elements will perform the actual scientific exploration in the deep sea or on the Moon. It is the overarching objective of the ROBEX Alliance is the equipment of these systems with innovative technologies for energy exchange and data transfer. Most processes should be conducted fully autonomously [4]. Science-critical decisions will be made semi-autonomously with Human-in-the Loop.

  13. 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.

  14. Seismicity and active tectonics in the Alboran Sea, Western Mediterranean: Constraints from an offshore-onshore seismological network and swath bathymetry data

    NASA Astrophysics Data System (ADS)

    Grevemeyer, Ingo; Gràcia, Eulàlia; Villaseñor, Antonio; Leuchters, Wiebke; Watts, Anthony B.

    2015-12-01

    Seismicity and tectonic structure of the Alboran Sea were derived from a large amphibious seismological network deployed in the offshore basins and onshore in Spain and Morocco, an area where the convergence between the African and Eurasian plates causes distributed deformation. Crustal structure derived from local earthquake data suggests that the Alboran Sea is underlain by thinned continental crust with a mean thickness of about 20 km. During the 5 months of offshore network operation, a total of 229 local earthquakes were located within the Alboran Sea and neighboring areas. Earthquakes were generally crustal events, and in the offshore domain, most of them occurred at crustal levels of 2 to 15 km depth. Earthquakes in the Alboran Sea are poorly related to large-scale tectonic features and form a 20 to 40 km wide NNE-SSW trending belt of seismicity between Adra (Spain) and Al Hoceima (Morocco), supporting the case for a major left-lateral shear zone across the Alboran Sea. Such a shear zone is in accord with high-resolution bathymetric data and seismic reflection imaging, indicating a number of small active fault zones, some of which offset the seafloor, rather than supporting a well-defined discrete plate boundary fault. Moreover, a number of large faults known to be active as evidenced from bathymetry, seismic reflection, and paleoseismic data such as the Yusuf and Carboneras faults were seismically inactive. Earthquakes below the Western Alboran Basin occurred at 70 to 110 km depth and hence reflected intermediate depth seismicity related to subducted lithosphere.

  15. Deep Structure of the Northeastern Gulf of Aden Margin From Wide-Angle Seismic Network

    NASA Astrophysics Data System (ADS)

    Watremez, L.; Leroy, S.; Rouzo, S.; D'Acremont, E.; Tiberi, C.; Burov, E.; Al-Lazki, A.

    2007-12-01

    The Gulf of Aden is an oblique rift system with spreading segments connected by several transform faults. Rifting in the gulf began ca. 35 Ma ago when the Afar hotspot activity takes place. Onset of spreading recorded by the first magnetic anomaly (A5d) is dated at least 17.6 Ma. We describe first results from the Encens seismic experiment in the northeastern Gulf of Aden and present crustal-scale images across three second-order segments between Alula-Fartak and Socotra fracture zones. Each of these segments was instrumented with 10-15 km, evenly spaced ocean-bottom seismometers complemented onshore by an array of seismometers. 8000 shots from the 8410 in3 ( ~ 138 l) source on board R/V L"Atalante (Ifremer) have been recorded, providing an extensive dataset, with offsets up to 180 km. Excellent-quality data from this dense source and receiver coverage enable the modeling of the P-waves across and along the strike of the ocean-continent transition (OCT) and continental margin for the different rift segments. Coincident multichannel seismic data is used to better constrain the structure down to the basement, and the crustal structure is eventually validated through the modeling of synthetic gravity anomalies. Our results indicate that a single morphology and geometry of the continental margins does not exist in the eastern Gulf of Aden. Indeed, distinct styles of rifting occur within the first-order segmentation of the gulf, which may be related to pre-rift history and to the syn or post-rift magmatism. The continental crust has a maximum of 35 km thickness in the west and 32 km in the east, with velocities ranging from 6 to 7.3 km/s. The base of the oceanic crust has relatively low P-wave velocities ranging from 6.6 to 7.5 km/s, and a thickness of about 5 km in the west and 7 km in the east. A 130 km long gradual thinning of the crust is observed while the OCT width ranges from 20 to 30 km. The transitional crust is around 8 km thick and the P-wave velocities are

  16. Tracking fin whales in the northeast Pacific Ocean with a seafloor seismic network.

    PubMed

    Wilcock, William S D

    2012-10-01

    Ocean bottom seismometer (OBS) networks represent a tool of opportunity to study fin and blue whales. A small OBS network on the Juan de Fuca Ridge in the northeast Pacific Ocean in ~2.3 km of water recorded an extensive data set of 20-Hz fin whale calls. An automated method has been developed to identify arrival times based on instantaneous frequency and amplitude and to locate calls using a grid search even in the presence of a few bad arrival times. When only one whale is calling near the network, tracks can generally be obtained up to distances of ~15 km from the network. When the calls from multiple whales overlap, user supervision is required to identify tracks. The absolute and relative amplitudes of arrivals and their three-component particle motions provide additional constraints on call location but are not useful for extending the distance to which calls can be located. The double-difference method inverts for changes in relative call locations using differences in residuals for pairs of nearby calls recorded on a common station. The method significantly reduces the unsystematic component of the location error, especially when inconsistencies in arrival time observations are minimized by cross-correlation. PMID:23039436

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

  18. Evaluation of infrasound signals from the shuttle Atlantis using a large seismic network.

    PubMed

    de Groot-Hedlin, Catherine D; Hedlin, Michael A H; Walker, Kristoffer T; Drob, Douglas P; Zumberge, Mark A

    2008-09-01

    Inclement weather in Florida forced the space shuttle "Atlantis" to land at Edwards Air Force Base in southern California on June 22, 2007, passing near three infrasound stations and several hundred seismic stations in northern Mexico, southern California, and Nevada. The high signal-to-noise ratio, broad receiver coverage, and Atlantis' positional information allow for the testing of infrasound propagation modeling capabilities through the atmosphere to regional distances. Shadow zones and arrival times are predicted by tracing rays that are launched at right angles to the conical shock front surrounding the shuttle through a standard climatological model as well as a global ground to space model. The predictions and observations compare favorably over much of the study area for both atmospheric specifications. To the east of the shuttle trajectory, there were no detections beyond the primary acoustic carpet. Infrasound energy was detected hundreds of kilometers to the west and northwest (NW) of the shuttle trajectory, consistent with the predictions of ducting due to the westward summer-time stratospheric jet. Both atmospheric models predict alternating regions of high and low ensonifications to the NW. However, infrasound energy was detected tens of kilometers beyond the predicted zones of ensonification, possibly due to uncertainties in stratospheric wind speeds. PMID:19045636

  19. Using the New Views of the Moon Initiative to Define Future Missions: The Lunar Seismic Network

    NASA Astrophysics Data System (ADS)

    Neal, C. R.

    2002-01-01

    The New Views of the Moon initiative is unprecedented in the history of lunar research because it has integrated remotely sensed and sample data in its approach to synthesizing lunar research over the last 30+ years. The integration of remotely sensed and sample data has clearly demonstrated what we know and, maybe more importantly, what we don't know about the Moon. Most significantly, it has helped to crystallize fundamental scientific questions that still need to be addressed and lessons learned from our study of the Moon and provides an invaluable road map for our exploration of the inner planets. The results of the New Views initiative highlight in explicit detail just how little we know about the nature of the lunar interior. While innovative modeling approaches have refined the original data, comprehensive and definitive interpretations of the lunar mantle remain elusive and fundamental questions regarding lunar origin, evolution, and structure remain unanswered. These include: What is the structure and thickness of the crust on the lunar near and far sides? Are crustal structure changes gradational or are distinct domains present? Is the approximately 500 km discontinuity a moon-wide phenomenon (magmasphere vs. magma ocean)? Do seismic data in the middle and deep lunar mantle define a unique garnet signature? What is the lunar core made of and how extensive is it? Are the core and mantle completely solid or do plastic zones still persist? Are nests producing Moon-quakes present on the far side?

  20. Probing a deep geothermal area in the upper rhine graben with ambient seismic noise : some results based on permanent networks and the dense temporary Estof array

    NASA Astrophysics Data System (ADS)

    Lehujeur, Maximilien; Vergne, Jérôme; Le Chenadec, Adrien; Schmittbuhl, Jean

    2016-04-01

    Correlation of ambient seismic noise is an emerging technique that allows to probe the subsoil with no natural or induced seismic sources. The method can be used for passive imaging or for monitoring the temporal evolution of the velocity and the diffracting properties of a medium. Recently, these techniques have been generalized to very dense seismological networks, which emerge as a new tool for the exploration, the characterization and the monitoring of deep geothermal reservoirs at much lower costs than active methods. The EstOf experiment that occured in september 2014 proposes to assess the potential of these techniques. Il consists in a dense network of 288 Zland ® seismological stations deployed every ~1.5km over a 15km radius disc around the two geothermal sites of Rittershoffen and Soultz-sous-forêts (Alsace, France). This temporary network complements several permanent and semi-permanent networks initially dedicated to the monitoring of the induced seismicity. The correlation of one month of ambient seismic noise provides thousands of usable correlation functions in the 0.2-5Hz frequency range. We clearly observe body waves as well as the fundamental mode and first overtone of the Rayleigh wave. The latter phases have been used to build a 3D model of shear wave velocities of the region down to 5km depth. This model, having a lateral resolution of about 2km, appears to be in good agreement with our geological knowledge of the region. Furthermore, the temporal analysis of the noise correlation functions between some permanent stations indicate sudden changes in the diffracting properties of the subsoil, which are probably linked to the stimulation phases of the reservoir conducted at Rittershoffen in 2013. However, interpreting these observations remains difficult. Laboratory experiments could be a useful approach to better understand the link between the changes in the medium parameters and the resulting effects on the noise-correlation functions.

  1. Passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Latham, G. V.; Ewing, M.; Press, F.; Sutton, G.; Dorman, J.; Nakamura, Y.; Toksoz, N.; Lammlein, D.; Duennebier, F.

    1972-01-01

    The establishment of a network of seismic stations on the lunar surface as a result of equipment installed by Apollo 12, 14, and 15 flights is described. Four major discoveries obtained by analyzing seismic data from the network are discussed. The use of the system to detect vibrations of the lunar surface and the use of the data to determine the internal structure, physical state, and tectonic activity of the moon are examined.

  2. Venus Interior Structure Mission (VISM): Establishing a Seismic Network on Venus

    NASA Technical Reports Server (NTRS)

    Stofan, E. R.; Saunders, R. S.; Senske, D.; Nock, K.; Tralli, D.; Lundgren, P.; Smrekar, S.; Banerdt, B.; Kaiser, W.; Dudenhoefer, J.

    1993-01-01

    Magellan radar data show the surface of Venus to contain a wide range of geologic features (large volcanoes, extensive rift valleys, etc.). Although networks of interconnecting zones of deformation are identified, a system of spreading ridges and subduction zones like those that dominate the tectonic style of the Earth do not appear to be present. In addition, the absence of a mantle low-viscosity zone suggests a strong link between mantle dynamics and the surface. As a natural follow-on to the Magellan mission, establishing a network of seismometers on Venus will provide detailed quantitative information on the large scale interior structure of the planet. When analyzed in conjunction with image, gravity, and topography information, these data will aid in constraining mechanisms that drive surface deformation.

  3. Los Alamos National Laboratory's high-performance data system

    SciTech Connect

    Mercier, C.; Chorn, G.; Christman, R.; Collins, B.

    1991-01-01

    Los Alamos National Laboratory is designing a High-Performance Data System (HPDS) that will provide storage for supercomputers requiring large files and fast transfer speeds. The HPDS will meet the performance requirements by managing data transfers from high-speed storage systems connected directly to a high-speed network. File and storage management software will be distributed in workstations. Network protocols will ensure reliable, wide-area network data delivery to support long-distance distributed processing. 3 refs., 2 figs.

  4. Using W-phase for regional source inversion: An application to the data from the virtual seismic network in the Western Pacific region

    NASA Astrophysics Data System (ADS)

    Liang, W.; Zhao, L.; Chen, P.; Yu, Y.; Liu, C.; Huang, B.; Kanamori, H.

    2009-12-01

    The W-phase inversion has been proven to be an efficient way to determine the magnitude and source mechanism of large earthquakes for tsunami warning purposes (Kanamori and Rivera, 2008). The Institute of Earth Sciences has exchanged seismic data in a real-time manner with other agencies in surrounding countries, including Japan, Vietnam, and Malaysia, to form a virtual seismic network in the western Pacific region. Any local organization may issue an earthquake report with its own data acquisition system individually. With the hypocentral information provided, we are able to apply this new technique to invert the data from this virtual regional network for the source mechanisms of large earthquakes which occurred on the major convergent plate boundary zones within 2-30 degrees. In this case, the W-phase will be completely retrieved in 1.5-12.5 minutes. To evaluate the reliability of inversion with this network geometry, we invert waveforms of scenario earthquakes synthesized by normal mode summation method. A series of examples were then studied to compare the difference between our results and the global CMT solutions. We hope this practical application will contribute to the tsunami mitigation and seismic hazard assessment in the Western Pacific and Southern Asia regions.

  5. Modulation and application of PRESToPLUS on K-SEIS to the southern Korean peninsula seismic network

    NASA Astrophysics Data System (ADS)

    Park, J.; Chi, H.; Lim, I.; Elia, L.; Festa, G.; Emolo, A.

    2013-12-01

    KMA(Korea Meteorological Agency) and KIGAM(Korea Institute of Geoscience and Mineral Resources) have started a project to construct EEWS(Earthquake Early Warning System) from 2007 in South Korea. After preliminary test of PRESTo, we have changed PRESToPLUS to make applicable it on K-SEIS(Korea-Speedy Earthquake Information System) enlarging the number of stations and study area belong to KIGAM and KMA around the Korean Peninsula. PRESToPLUS has been changed to be applied on K-SEIS with powerful performance allowing more than 100 stations real-time streaming and larger study area including off-shore areas around the southern part of the Korean Peninsula. For the modulation the code of PRESToPLUS has been revised in the Linux OS and Windows 64 bit machines respectively. Whole earthquake catalog was play-backed in PRESToPLUS in order to get parameterization to account for Korean seismicity and existing network. A new regression law for magnitude estimation (RTMag Module) was defined by extraction of Magnitude, hypocentral distance and Pd measured on 4s P-waves signal at all stations. The new law of RTMag is logPd= -4.012+0.583M-1.033logR. With extraction of PGD, PGA, PGV, epicentral distance at stations from the earthquake catalog we can derive new Ground Motion Prediction Equations to use in PGx prediction at target sites in PRESToPLUS. The new regression law is logPGA=0.615+0.7M-1.68log(R^2+100)^(1/2). Theoretical analysis of the number of triggered stations for all possible events across Korea was done to derive the best parameterization of time windows for the earthquake detection (Binder Module). After analysis of performance PRESToPLUS we can conclude 8 picks and 8 second condition might be best for reliable event detection with current station network setting.

  6. Earthquakes and Volcanic Processes at San Miguel Volcano, El Salvador, Determined from a Small, Temporary Seismic Network

    NASA Astrophysics Data System (ADS)

    Hernandez, S.; Schiek, C. G.; Zeiler, C. P.; Velasco, A. A.; Hurtado, J. M.

    2008-12-01

    The San Miguel volcano lies within the Central American volcanic chain in eastern El Salvador. The volcano has experienced at least 29 eruptions with Volcano Explosivity Index (VEI) of 2. Since 1970, however, eruptions have decreased in intensity to an average of VEI 1, with the most recent eruption occurring in 2002. Eruptions at San Miguel volcano consist mostly of central vent and phreatic eruptions. A critical challenge related to the explosive nature of this volcano is to understand the relationships between precursory surface deformation, earthquake activity, and volcanic activity. In this project, we seek to determine sub-surface structures within and near the volcano, relate the local deformation to these structures, and better understand the hazard that the volcano presents in the region. To accomplish these goals, we deployed a six station, broadband seismic network around San Miguel volcano in collaboration with researchers from Servicio Nacional de Estudios Territoriales (SNET). This network operated continuously from 23 March 2007 to 15 January 2008 and had a high data recovery rate. The data were processed to determine earthquake locations, magnitudes, and, for some of the larger events, focal mechanisms. We obtained high precision locations using a double-difference approach and identified at least 25 events near the volcano. Ongoing analysis will seek to identify earthquake types (e.g., long period, tectonic, and hybrid events) that occurred in the vicinity of San Miguel volcano. These results will be combined with radar interferometric measurements of surface deformation in order to determine the relationship between surface and subsurface processes at the volcano.

  7. A Datacenter Backstage: The Knowledge that Supports the Brazilian Seismic Network

    NASA Astrophysics Data System (ADS)

    Calhau, J.; Assumpcao, M.; Collaço, B.; Bianchi, M.; Pirchiner, M.

    2015-12-01

    Historically, Brazilian seismology never had a clear strategic vision about how its data should be acquired, evaluated, stored and shared. Without a data management plan, data (for any practical purpose) could be lost, resulting in a non-uniform coverage that will reduce any chance of local and international collaboration, i.e., data will never become scientific knowledge. Since 2009, huge efforts from four different institutions are establishing the new permanent Brazilian Seismographic Network (RSBR), mainly with resources from PETROBRAS, the Brazilian Government oil company. Four FDSN sub-networks currently compose RSBR, with a total of 80 permanent stations. BL and BR codes (from BRASIS subnet) with 47 stations maintained by University of Sao Paulo (USP) and University of Brasilia (UnB) respectively; NB code (RSISNE subnet), with 16 stations deployed by University of Rio Grande do Norte (UFRN); and ON code (RSIS subnet), with 18 stations operated by the National Observatory (ON) in Rio de Janeiro. Most stations transmit data in real-time via satellite or cell-phone links. Each node acquires its own stations locally, and data is real-time shared using SeedLink. Archived data is distributed via ArcLink and/or FDSNWS services. All nodes use the SeisComP3 system for real-time processing and as a levering back-end. Open-source solutions like Seiscomp3 require some homemade tools to be developed, to help solve the most common daily problems of a data management center: local magnitude into the real-time earthquake processor, website plugins, regional earthquake catalog, contribution with ISC catalog, quality-control tools, data request tools, etc. The main data products and community activities include: kml files, data availability plots, request charts, summer school courses, an Open Lab Day and news interviews. Finally, a good effort was made to establish BRASIS sub-network and the whole RSBR as a unified project, that serves as a communication channel between

  8. Time-lapse seismic tomography using the data of microseismic monitoring network and analysis of mine-induced events, seismic tomography results and technological data in Pyhäsalmi mine, Finland

    NASA Astrophysics Data System (ADS)

    Nevalainen, Jouni; Kozlovskaya, Elena

    2016-04-01

    We present results of a seismic travel-time tomography applied to microseismic data from the Pyhäsalmi mine, Finland. The data about microseismic events in the mine is recorded since 2002 when the passive microseismic monitoring network was installed in the mine. Since that over 130000 microseismic events have been observed. The first target of our study was to test can the passive microseismic monitoring data be used with travel-time tomography. In this data set the source-receiver geometry is based on non-even distribution of natural and mine-induced events inside and in the vicinity of the mine and hence, is a non-ideal one for the travel-time tomography. The tomographic inversion procedure was tested with the synthetic data and real source-receiver geometry from Pyhäsalmi mine and with the real travel-time data of the first arrivals of P-waves from the microseismic events. The results showed that seismic tomography is capable to reveal differences in seismic velocities in the mine area corresponding to different rock types. For example, the velocity contrast between the ore body and surrounding rock is detectable. The velocity model recovered agrees well with the known geological structures in the mine area. The second target of the study was to apply the travel-time tomography to microseismic monitoring data recorded during different time periods in order to track temporal changes in seismic velocities within the mining area as the excavation proceeds. The result shows that such a time-lapse travel-time tomography can recover such changes. In order to obtain good ray coverage and good resolution, the time interval for a single tomography round need to be selected taking into account the number of events and their spatial distribution. The third target was to compare and analyze mine-induced event locations, seismic tomography results and mining technological data (for example, mine excavation plans) in order to understand the influence of mining technology

  9. 3D modelling of the active normal fault network in the Apulian Ridge (Eastern Mediterranean Sea): Integration of seismic and bathymetric data with implicit surface methods

    NASA Astrophysics Data System (ADS)

    Bistacchi, Andrea; Pellegrini, Caludio; Savini, Alessandra; Marchese, Fabio

    2016-04-01

    The Apulian ridge (North-eastern Ionian Sea, Mediterranean), interposed between the facing Apennines and Hellenides subduction zones (to the west and east respectively), is characterized by thick cretaceous carbonatic sequences and discontinuous tertiary deposits crosscut by a penetrative network of NNW-SSE normal faults. These are exposed onshore in Puglia, and are well represented offshore in a dataset composed of 2D seismics and wells collected by oil companies from the '60s to the '80s, more recent seismics collected during research projects in the '90s, recent very high resolution seismics (VHRS - Sparker and Chirp-sonar data), multibeam echosounder bathymetry, and sedimentological and geo-chronological analyses of sediment samples collected on the seabed. Faults are evident in 2D seismics at all scales, and their along-strike geometry and continuity can be characterized with multibeam bathymetric data, which show continuous fault scarps on the seabed (only partly reworked by currents and covered by landslides). Fault scarps also reveal the finite displacement accumulated in the Holocene-Pleistocene. We reconstructed a 3D model of the fault network and suitable geological boundaries (mainly unconformities due to the discontinuous distribution of quaternary and tertiary sediments) with implicit surface methods implemented in SKUA/GOCAD. This approach can be considered very effective and allowed reconstructing in details complex structures, like the frequent relay zones that are particularly well imaged by seafloor geomorphology. Mutual cross-cutting relationships have been recognized between fault scarps and submarine mass-wasting deposits (Holocene-Pleistocene), indicating that, at least in places, these features are coeval, hence the fault network should be considered active. At the regional scale, the 3D model allowed measuring the horizontal WSW-ENE stretching, which can be associated to the bending moment applied to the Apulian Plate by the combined effect

  10. Cross-correlation analysis of 2012-2014 seismic events in Central-Northern Italy: insights from the geochemical monitoring network of Tuscany

    NASA Astrophysics Data System (ADS)

    Pierotti, Lisa; Facca, Gianluca; Gherardi, Fabrizio

    2015-04-01

    Since late 2002, a geochemical monitoring network is operating in Tuscany, Central Italy, to collect data and possibly identify geochemical anomalies that characteristically occur before regionally significant (i.e. with magnitude > 3) seismic events. The network currently consists of 6 stations located in areas already investigated in detail for their geological setting, hydrogeological and geochemical background and boundary conditions. All these stations are equipped for remote, continuous monitoring of selected physicochemical parameters (temperature, pH, redox potential, electrical conductivity), and dissolved concentrations of CO2 and CH4. Additional information are obtained through in situ discrete monitoring. Field surveys are periodically performed to guarantee maintenance and performance control of the sensors of the automatic stations, and to collect water samples for the determination of the chemical and stable isotope composition of all the springs investigated for seismic precursors. Geochemical continuous signals are numerically processed to remove outliers, monitoring errors and aseismic effects from seasonal and climatic fluctuations. The elaboration of smoothed, long-term time series (more than 200000 data available today for each station) allows for a relatively accurate definition of geochemical background values. Geochemical values out of the two-sigma relative standard deviation domain are inspected as possible indicators of physicochemical changes related to regional seismic activity. Starting on November 2011, four stations of the Tuscany network located in two separate mountainous areas of Northern Apennines separating Tuscany from Emilia-Romagna region (Equi Terme and Gallicano), and Tuscany from Emilia-Romagna and Umbria regions (Vicchio and Caprese Michelangelo), started to register anomalous values in pH and CO2 partial pressure (PCO2). Cross-correlation analysis indicates an apparent relationship between the most important seismic

  11. A high-resolution 3D seismic velocity model of the 2010 Mw 8.8 Maule, Chile earthquake rupture zone using land & OBS networks

    NASA Astrophysics Data System (ADS)

    Hicks, S. P.; Rietbrock, A.; Ryder, I. M.; Miller, M.; Lee, C.

    2013-12-01

    Knowledge of seismic properties along a subduction megathrust can shed light on the composition and structure of rocks along the fault. By comparing seismic velocity structure with models of interseismic locking, co-seismic slip and afterslip, we can begin to understand how physical properties may affect fault dynamics throughout the subduction seismic cycle. The Maule earthquake, which hit the coast of central Chile in 2010, is the 6th largest earthquake ever recorded, rupturing a 500 x 80 km area of the Chilean megathrust. Published models demonstrate a complex bilateral rupture, with most co-seismic slip occurring to the north of the mainshock epicentre, although significant slip likely stopped short of the trench and the continental Moho. Here, we show a new high-resolution 3D velocity model (vp and vp/vs ratio) of the central Chilean margin Our velocity model is based on manually picked P- and S-wave arrival times from 670 aftershocks recorded by the International Maule Aftershock Deployment (IMAD) network. Seismic properties of the marine forearc are poorly understood in subduction zones, but by incorporating picks from two ocean-bottom seismometer (OBS) networks, we can resolve the velocity structure of the megathrust as far as the trench. In total, the catalogue used for the tomographic inversion yields a total of ~50,000 high quality P- and S-wave picks. We analyse the quality of our model by analysis of the resolution matrix and by testing characteristic models. The 3D velocity model shows the main structures associated within a subduction forearc: the marine forearc basin (vp < 6.0 km/s), continental mantle (vp > 7.5 km/s), and subducting oceanic crust (vp ~ 7.7 km/s). The plate interface is well defined by relocated aftershock seismicity. P-wave velocities along the megathrust range from 6.5 km/s beneath the marine forearc to 7.7 km/s at the intersection of the megathrust with the continental Moho. We infer several high vp anomalies within the South

  12. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory's Source Region Program

    SciTech Connect

    Whitaker, R.W.; Noel, S.D.

    1992-12-01

    The summary report by Tom Weaver gives the overall background for the series of IVE (Integrated Verification Experiment) experiments including information on the full set of measurements made. This appendix presents details of the infrasound data for the and discusses certain aspects of a few special experiments. Prior to FY90, the emphasis of the Infrasound Program was on underground nuclear test (UGT) detection and yield estimation. During this time the Infrasound Program was a separate program at Los Alamos, and it was suggested to DOE/OAC that a regional infrasound network be established around NTS. The IVE experiments took place in a time frame that allowed simultaneous testing of possible network sites and examination of propagation in different directions. Whenever possible, infrasound stations were combined with seismic stations so that a large number could be efficiently fielded. The regional infrasound network was not pursued by DOE, as world events began to change the direction of verification toward non-proliferation. Starting in FY90 the infrasound activity became part of the Source Region Program which has a goal of understanding how energy is transported from the UGT to a variety of measurement locations.

  13. Los Alamos National Laboratory

    SciTech Connect

    Dogliani, Harold O

    2011-01-19

    The purpose of the briefing is to describe general laboratory technical capabilities to be used for various groups such as military cadets or university faculty/students and post docs to recruit into a variety of Los Alamos programs. Discussed are: (1) development and application of high leverage science to enable effeictive, predictable and reliability outcomes; (2) deter, detect, characterize, reverse and prevent the proliferation of weapons of mass destruction and their use by adversaries and terrorists; (3) modeling and simulation to define complex processes, predict outcomes, and develop effective prevention, response, and remediation strategies; (4) energetic materials and hydrodynamic testing to develop materials for precise delivery of focused energy; (5) materials cience focused on fundamental understanding of materials behaviors, their quantum-molecular properties, and their dynamic responses, and (6) bio-science to rapidly detect and characterize pathogens, to develop vaccines and prophylactic remedies, and to develop attribution forensics.

  14. 3-D P-wave velocity structure and seismicity in Central Costa Rica from Local Earthquake Tomography using an amphibic network

    NASA Astrophysics Data System (ADS)

    Arroyo, I.; Husen, S.; Flueh, E.; Alvarado, G. E.

    2008-12-01

    The Central Pacific sector of the erosional margin in Costa Rica shows a high seismicity rate, coincident with the subduction of rough-relief ocean floor, and generates earthquakes up to Mw 7. Precise earthquake locations and detailed knowledge of the 3-D velocity structure provide key insights into the dynamics of subduction zones. To this end, we performed a 3-D Local Earthquake Tomography using P-wave traveltimes from 595 selected events recorded by a seismological network of off- and onshore stations, deployed for 6 months in the area. The results reflect the complexity associated to subduction of bathymetric highs and the transition from normal to thickened oceanic crust (Cocos Ridge). The slab is imaged as a high-velocity anomaly with a band of low velocities (LVB) on top enclosing the intraslab events deeper than ~30 km. Below the margin slope, the LVB is locally thickened by at least two seamounts. We observe an abrupt, eastward widening of the LVB, preceded by a low-velocity anomaly under the continental shelf, which we interpret as a big seamount. The thickening coincides with an inverted basin at the inner forearc and a low-velocity anomaly under it. The latter appears in a sector where blocks of inner forearc are uplifted, possibly by underplating of eroded material against the base of the crust. The anomaly promotes seismicity by high-friction with the upper plate, and could be linked to a Mw 6.4 earthquake in 2004. In the west part of the area, the interplate seismicity forms a cluster beneath the continental shelf. Its updip limit coincides with the 150° C isotherm and an increase in Vp along the plate boundary. This further supports a proposed model in which the seismicity onset along the plate interface is mainly due to a decrease in the abundance of the fluids released by subducted sediments. Higher seismicity rates locally concur with seamounts present at the seismogenic zone, while seamounts under the margin slope may shallow the onset of

  15. Operation of a digital seismic network on Mount St. Helens volcano and observations of long period seismic events that originate under the volcano

    SciTech Connect

    Fehler, M.; Chouet, B.

    1982-09-01

    A 9 station digital seismic array was operated on Mount St. Helens volcano in Washington State during 1981. One of the stations was placed inside the crater of the volcano, six were located on the flanks of the volcano within two km of the crater and two were approximately ten km from the crater. Four of the instruments recorded three components of motion and the remaining five recorded only the vertical component. A one day experiment was carried out during which the crater monitoring seismometer was complimented by the addition of two ink recording instruments. During the one day experiment six observers recorded times of rockfall, felt-earthquake occurrences, and changes in steam emissions from the dome in the crater. Using information obtained during the one day experiment seismic events recorded by the digital instruments were classified as earthquakes, rockfalls, helicopter noise and a type of event that is unique to volcanoes which is called long period. Waveforms of these long period events have a duration of up to 30 seconds and a spectrum that is peaked at approximately 2 Hz. The frequency at which the peak in the spectrum occurs is nearly the same at all stations which means that the unique waveform of long period events is due to a source effect, not a path effect. The peak frequency is fairly insensitive to the amplitude of the signal which means that the size of the source region is constant, independent of the signal amplitude. Long period events were not felt and were accompanied by no visible changes inside the crater which lead to the conclusion that they are some sort of seismic disturbance generated inside the Volcano.

  16. Seismic velocity estimation from well log data with genetic algorithms in comparison to neural networks and multilinear approaches

    NASA Astrophysics Data System (ADS)

    Aleardi, Mattia

    2015-06-01

    Predicting missing log data is a useful capability for geophysicists. Geophysical measurements in boreholes are frequently affected by gaps in the recording of one or more logs. In particular, sonic and shear sonic logs are often recorded over limited intervals along the well path, but the information these logs contain is crucial for many geophysical applications. Estimating missing log intervals from a set of recorded logs is therefore of great interest. In this work, I propose to estimate the data in missing parts of velocity logs using a genetic algorithm (GA) optimisation and I demonstrate that this method is capable of extracting linear or exponential relations that link the velocity to other available logs. The technique was tested on different sets of logs (gamma ray, resistivity, density, neutron, sonic and shear sonic) from three wells drilled in different geological settings and through different lithologies (sedimentary and intrusive rocks). The effectiveness of this methodology is demonstrated by a series of blind tests and by evaluating the correlation coefficients between the true versus predicted velocity values. The combination of GA optimisation with a Gibbs sampler (GS) and subsequent Monte Carlo simulations allows the uncertainties in the final predicted velocities to be reliably quantified. The GA method is also compared with the neural networks (NN) approach and classical multilinear regression. The comparisons show that the GA, NN and multilinear methods provide velocity estimates with the same predictive capability when the relation between the input logs and the seismic velocity is approximately linear. The GA and NN approaches are more robust when the relations are non-linear. However, in all cases, the main advantages of the GA optimisation procedure over the NN approach is that it directly provides an interpretable and simple equation that relates the input and predicted logs. Moreover, the GA method is not affected by the disadvantages

  17. Three-month performance evaluation of the Nanometrics, Inc., Libra Satellite Seismograph System in the northern California Seismic Network

    USGS Publications Warehouse

    Oppenheimer, David H.

    2000-01-01

    In 1999 the Northern California Seismic Network (NCSN) purchased a Libra satellite seismograph system from Nanometrics, Inc to assess whether this technology was a cost-effective and robust replacement for their analog microwave system. The system was purchased subject to it meeting the requirements, criteria and tests described in Appendix A. In early 2000, Nanometrics began delivery of various components of the system, such as the hub and remote satellite dish and mounting hardware, and the NCSN installed and assembled most equipment in advance of the arrival of Nanometrics engineers to facilitate the configuration of the system. The hub was installed in its permanent location, but for logistical reasons the "remote" satellite hardware was initially configured at the NCSN for testing. During the first week of April Nanometrics engineers came to Menlo Park to configure the system and train NCSN staff. The two dishes were aligned with the satellite, and the system was fully operational in 2 days with little problem. Nanometrics engineers spent the remaining 3 days providing hands-on training to NCSN staff in hardware/software operation, configuration, and maintenance. During the second week of April 2000, NCSN staff moved the entire remote system of digitizers, dish assembly, and mounting hardware to Mammoth Lakes, California. The system was reinstalled at the Mammoth Lakes water treatment plant and communications successfully reestablished with the hub via the satellite on 14 April 2000. The system has been in continuous operation since then. This report reviews the performance of the Libra system for the three-month period 20 April 2000 through 20 July 2000. The purpose of the report is to assess whether the system passed the acceptance tests described in Appendix A. We examine all data gaps reported by NCSN "gap list" software and discuss their cause.

  18. Impact of the 2001 Tohoku-oki earthquake to Tokyo Metropolitan area observed by the Metropolitan Seismic Observation network (MeSO-net)

    NASA Astrophysics Data System (ADS)

    Hirata, N.; Hayashi, H.; Nakagawa, S.; Sakai, S.; Honda, R.; Kasahara, K.; Obara, K.; Aketagawa, T.; Kimura, H.; Sato, H.; Okaya, D. A.

    2011-12-01

    The March 11, 2011 Tohoku-oki earthquake brought a great impact to the Tokyo metropolitan area in both seismological aspect and seismic risk management although Tokyo is located 340 km from the epicenter. The event generated very strong ground motion even in the metropolitan area and resulted severe requifaction in many places of Kanto district. National and local governments have started to discuss counter measurement for possible seismic risks in the area taking account for what they learned from the Tohoku-oki event which is much larger than ever experienced in Japan Risk mitigation strategy for the next greater earthquake caused by the Philippine Sea plate (PSP) subducting beneath the Tokyo metropolitan area is of major concern because it caused past mega-thrust earthquakes, such as the 1703 Genroku earthquake (M8.0) and the 1923 Kanto earthquake (M7.9). An M7 or greater (M7+) earthquake in this area at present has high potential to produce devastating loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates that an M7+ earthquake will cause 11,000 fatalities and 112 trillion yen (about 1 trillion US$) economic loss. In order to mitigate disaster for greater Tokyo, the Special Project for Earthquake Disaster Mitigation in the Tokyo Metropolitan Area was launched in collaboration with scientists, engineers, and social-scientists in nationwide institutions. We will discuss the main results that are obtained in the respective fields which have been integrated to improve information on the strategy assessment for seismic risk mitigation in the Tokyo metropolitan area; the project has been much improved after the Tohoku event. In order to image seismic structure beneath the Metropolitan Tokyo area we have developed Metropolitan Seismic Observation network (MeSO-net; Hirata et al., 2009). We have installed 296 seismic stations every few km (Kasahara et al., 2011). We conducted seismic

  19. 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.

  20. Los Alamos National Laboratory Overview

    SciTech Connect

    Neu, Mary

    2010-06-02

    Mary Neu, Associate Director for Chemistry, Life and Earth Sciences at Los Alamos National Laboratory, delivers opening remarks at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM

  1. Onshore-offshore seismic networks: an inescapable approach to reveal the crustal structure and the seismic activity of large subduction zones

    NASA Astrophysics Data System (ADS)

    Charvis, P.; Galve, A.; Laigle, M.; Hirn, A.; Hello, Y. M.; Oge, A.; Yates, B. A.

    2013-12-01

    Ninety percent of the seismic energy released worldwide and ninety percent of the largest earthquakes and tsunamis occur in subduction zones. Several recent catastrophic subduction earthquakes surprised us on many aspects, either because we had been unable to anticipate their extremely large magnitude (2011 Tohoku Earthquake, Mw 9.0), or because we had considered the subduction as partly aseismic (2004 Sumatra Andaman earthquake, Mw 9.1). One of the reasons for our present ignorance of the behavior of large subduction earthquakes is the lack of marine data to image and monitor the structure and evolution of megathrust faults offshore. Over the last 15 years, our group has conducted several passive and active seismic experiments* in the forearc regions of the Ecuador-Colombia, Lesser Antilles and Hellenic subduction zones. The objectives of these experiments were to image the subduction interplate fault at depth and accurately locate the current earthquake activity of the megathrusts using arrays of combined ocean-bottom and land-based seismometers. In the case of very large events and in the absence of geodetic data in the offshore part of the faults, the precise knowledge of current seismicity is mandatory to estimate the seismogenic behavior and potential of the fault interface. 2D dense active seismic lines, shot jointly with multichannel acquisitions, provide invaluable images of the deep structure of the Lesser Antilles arc and forearc, which allow locating the updip and downdip limits of the expected seismogenic zone. Assuming that the Moho is the downdip limit of the seismogenic zone, the 26 km-thick crust of the arc makes the seismogenic zone 3 times wider than it is in ';standard' oceanic arcs (like Marianas). 3D active and passive experiments in the Lesser Antilles and Ecuador forearcs provide an unprecedented way to image the structure in 3D down to the lower plate. The tomography documents the spatial variability of the interplate fault structure and of

  2. Discrimination of nuclear explosions and earthquakes from teleseismic distances with a local network of short period seismic stations using artificial neural networks

    NASA Astrophysics Data System (ADS)

    Tiira, Timo

    1996-10-01

    Seismic discrimination capability of artificial neural networks (ANNs) was studied using earthquakes and nuclear explosions from teleseismic distances. The events were selected from two areas, which were analyzed separately. First, 23 nuclear explosions from Semipalatinsk and Lop Nor test sites were compared with 46 earthquakes from adjacent areas. Second, 39 explosions from Nevada test site were compared with 27 earthquakes from close-by areas. The basic discriminants were complexity, spectral ratio and third moment of frequency. The spectral discriminants were computed in five different ways to obtain all the information embedded in the signals, some of which were relatively weak. The discriminants were computed using data from six short period stations in Central and southern Finland. The spectral contents of the signals of both classes varied considerably between the stations. The 66 discriminants were formed into 65 optimum subsets of different sizes by using stepwise linear regression. A type of ANN called multilayer perceptron (MLP) was applied to each of the subsets. As a comparison the classification was repeated using linear discrimination analysis (LDA). Since the number of events was small the testing was made with the leave-one-out method. The ANN gave significantly better results than LDA. As a final tool for discrimination a combination of the ten neural nets with the best performance were used. All events from Central Asia were clearly discriminated and over 90% of the events from Nevada region were confidently discriminated. The better performance of ANNs was attributed to its ability to form complex decision regions between the groups and to its highly non-linear nature.

  3. A progress report on UNICOS misuse detection at Los Alamos

    SciTech Connect

    Thompson, J.L.; Jackson, K.A.; Stallings, C.A.; Simmonds, D.D.; Siciliano, C.L.B.; Pedicini, G.A.

    1995-10-01

    An effective method for detecting computer misuse is the automatic monitoring and analysis of on-line user activity. During the past year, Los Alamos enhanced its Network Anomaly Detection and Intrusion Reporter (NADIR) to include analysis of user activity on Los Alamos` UNICOS Crays. In near real-time, NADIR compares user activity to historical profiles and tests activity against expert rules. The expert rules express Los Alamos` security policy and define improper or suspicious behavior. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes the implementation to date of the UNICOS component of NADIR, along with the operational experiences and future plans for the system.

  4. Waveform through the subducted plate under the Tokyo region in Japan observed by a ultra-dense seismic network (MeSO-net) and seismic activity around mega-thrust earthquakes area

    NASA Astrophysics Data System (ADS)

    Sakai, S.; Kasahara, K.; Nanjo, K.; Nakagawa, S.; Tsuruoka, H.; Morita, Y.; Kato, A.; Iidaka, T.; Hirata, N.; Tanada, T.; Obara, K.; Sekine, S.; Kurashimo, E.

    2009-12-01

    In central Japan, the Philippine Sea plate (PSP) subducts beneath the Tokyo Metropolitan area, the Kanto region, where it causes mega-thrust earthquakes, such as the 1703 Genroku earthquake (M8.0) and the 1923 Kanto earthquake (M7.9) which had 105,000 fatalities. A M7 or greater earthquake in this region at present has high potential to produce devastating loss of life and property with even greater global economic repercussions. The Central Disaster Management Council of Japan estimates the next great earthquake will cause 11,000 fatalities and 112 trillion yen (1 trillion US$) economic loss. This great earthquake is evaluated to occur with a probability of 70 % in 30 years by the Earthquake Research Committee of Japan. We had started the Special Project for Earthquake Disaster Mitigation in Tokyo Metropolitan area (2007-2012). Under this project, the construction of the Metropolitan Seismic Observation network (MeSO-net) that consists of about 400 observation sites was started [Kasahara et al., 2008; Nakagawa et al., 2008]. Now, we had 178 observation sites. The correlation of the wave is high because the observation point is deployed at about 2 km intervals, and the identification of the later phase is recognized easily thought artificial noise is very large. We also discuss the relation between a deformation of PSP and intra-plate M7+ earthquakes: the PSP is subducting beneath the Honshu arc and also colliding with the Pacific plate. The subduction and collision both contribute active seismicity in the Kanto region. We are going to present a high resolution tomographic image to show low velocity zone which suggests a possible internal failure of the plate; a source region of the M7+ intra-plate earthquake. Our study will contribute a new assessment of the seismic hazard at the Metropolitan area in Japan. Acknowledgement: This study was supported by the Earthquake Research Institute cooperative research program.

  5. Application of Self Adaptive Unsupervised Neural Networks for Processing of VLF-LF signals to detect Seismic-Ionospheric Precursor Phenomena.

    NASA Astrophysics Data System (ADS)

    Skeberis, C.; Xenos, T. D.; Hadjileontiadis, L.; Contadakis, M. E.; Arabelos, D.

    2012-04-01

    This paper investigates the development and application of artificial neural networks (ANN) based on Predictive Modular Neural Networks (PREMONNs) to provide a self adaptive unsupervised method for detecting disturbances that can be attributed to seismic-ionospheric precursor phenomena using VLF radio signals. As such, the neural network is applied to bring forth and adaptively discriminate different characteristics in the received signals, in real time, in order to provide data segments of interest that can be correlated to subsequent seismic phenomena. PREMONNs have been developed for time series prediction and through that for source switching detection in a time series; they are constituted by two modules. The first tier is a module consisting of a dynamic array of neural networks following the data stream in order to predict the next value of a time series whereas the second is a decision one utilizing a Bayes probability equation to decide on source switching. That module is responsible for electing and appropriately training the closest fitting NN or switching to a new NN if a source switch is apparent. For the purpose of this paper, VLF signals transmitted by a number of European VLF transmitters are monitored for over a year in Thessaloniki (40.69N 22.78E) and the data from December 2010 to December 2011 are used. The received signals are sampled and stored for off line processing. The receiver was developed by Elettronika Srl, and is part of the International Network for Frontier Research on Earthquake Precursors (INFREP). Signals received from the 20.27KHz ICV station in Tavolara, Italy (Lat 40.923,Lon. 9.731) were used. The received VLF signal was normalized and then processed using the Empirical Mode Decomposition Method (EMD). The resulting data are used to train the unsupervised ANN and the performance of the developed network is then evaluated. The efficacy of different layouts of the PREMONN is evaluated and the application of a self

  6. Ambient seismic noise levels: A survey of the permanent and temporary seismographic networks in Morocco, North Africa

    NASA Astrophysics Data System (ADS)

    El Fellah, Y.; Khairy Abd Ed-Aal, A.; El Moudnib, L.; Mimoun, H.; Villasenor, A.; Gallart, J.; Thomas, C.; Elouai, D.; Mimoun, C.; Himmi, M.

    2013-12-01

    Abstract The results, of a conducted study carried out to analyze variations in ambient seismic noise levels at sites of the installed broadband stations in Morocco, North Africa, are obtained. The permanent and the temporary seismic stations installed in Morocco of the Scientific Institute ( IS, Rabat, Morocco), institute de Ciencias de la Tierra Jaume almera (ICTJA, Barcelona, Spain) and Institut für Geophysik (Munster, Germany) were used in this study. In this work, we used 23 broadband seismic stations installed in different structural domains covering all Morocco from south to north. The main purposes of the current study are: 1) to present a catalog of seismic background noise spectra for Morocco obtained from recently installed broadband stations, 2) to assess the effects of experimental temporary seismic vault construction, 3) to determine the time needed for noise at sites to stabilize, 4) to establish characteristics and origin of seismic noise at those sites. We calculated power spectral densities of background noise for each component of each broadband seismometer deployed in the different investigated sites and then compared them with the high-noise model and low-noise Model of Peterson (1993). All segments from day and night local time windows were included in the calculation without parsing out earthquakes. The obtained results of the current study could be used forthcoming to evaluate permanent station quality. Moreover, this study could be considered as a first step to develop new seismic noise models in North Africa not included in Peterson (1993). Keywords Background noise; Power spectral density; Model of Peterson; Scientific Institute; Institute de Ciencias de la Tierra Jaume almera; Institut für Geophysik

  7. Products and Services Available from the Southern California Earthquake Data Center (SCEDC) and the Southern California Seismic Network (SCSN)

    NASA Astrophysics Data System (ADS)

    Yu, E.; Chen, S.; Chowdhury, F.; Bhaskaran, A.; Hutton, K.; Given, D.; Hauksson, E.; Clayton, R. W.

    2009-12-01

    The SCEDC archives continuous and triggered data from nearly 3000 data channels from 375 SCSN recorded stations. The SCSN and SCEDC process and archive an average of 12,000 earthquakes each year, contributing to the southern California earthquake catalog that spans from 1932 to present. The SCEDC provides public, searchable access to these earthquake parametric and waveform data through its website www.data.scec.org and through client applications such as STP, NETDC and DHI. New data products: ● The SCEDC is distributing synthetic waveform data from the 2008 ShakeOut scenario (Jones et al., USGS Open File Rep., 2008-1150) and (Graves et al. 2008; Geophys. Res. Lett.) This is a M 7.8 earthquake on the southern San Andreas fault. Users will be able to download 40 sps velocity waveforms in SAC format from the SCEDC website. The SCEDC is also distributing synthetic GPS data (Crowell et al., 2009; Seismo. Res. Letters.) for this scenario as well. ● The SCEDC has added a new web page to show the latest tomographic model of Southern California. This model is based on Tape et al., 2009 Science. New data services: ● The SCEDC is exporting data in QuakeML format. This is an xml format that has been adopted by the Advanced National Seismic System (ANSS). This data will also be available as a web service. ● The SCEDC is exporting data in StationXML format. This is an xml format created by the SCEDC and adopted by ANSS to fully describe station metadata. This data will also be available as a web service. ● The stp 1.6 client can now access both the SCEDC and the Northern California Earthquake Data Center (NCEDC) earthquake and waveform archives. In progress - SCEDC to distribute 1 sps GPS data in miniSEED format: ● As part of a NASA Advanced Information Systems Technology project in collaboration with Jet Propulsion Laboratory and Scripps Institution of Oceanography, the SCEDC will receive real time 1 sps streams of GPS displacement solutions from the California

  8. Toward an Earthquake Early Warning System in Israel - Implementing ElarmS for the Israeli Seismic Network

    NASA Astrophysics Data System (ADS)

    Nof, R. N.; Allen, R. M.

    2015-12-01

    Israel is located adjacent to the Dead Sea Transform (DST) capable of producing earthquakes with maximal magnitudes of M7.5-M7.8 and a recurrence time for a M6 and M7 earthquake on the order of 100 and 1000 years, respectively. The most recent destructive earthquake along the DST was the 1927 ML 6.2 earthquake near Jericho, leading to 285 deaths and ~1000 injured across the area. The Israeli government is now building an Earthquake Early Warning System (EEWS). The prime objective of this research is to implement and validate the ElarmS EEWS for the Israeli Seismological Network (ISN). Based on seismic rates along the DST, earthquakes with M>4.5 and M>5.0 are expected to occur every 5yr and 15yr, respectively. Thus, it is essential to use historical data to evaluate ElarmS in addition to analyzing the real-time performance of the system in Israel with smaller magnitude earthquakes. We analyze the system in real-time between April 2015 and July 2015, and analyze the results of replaying historical data from 39 events (Md>3.0) between January 2012 and May 2015. Historical playback results show near complete detection of all events. However, ElarmS has a mean underestimation of magnitudes by 1 magnitude order using the magnitude scaling relation developed for California. We find that using a previously determined independent magnitude estimation equation developed for Israel (Sadeh et al., 2014) remove this magnitude offset. Using the adjusted magnitude estimation equation, the real time performance of the system shows a good agreement with catalog magnitudes. The real-time implementation of ElarmS in Israel is performing well. It issued a warning for the June 27, 2015 M5.5 Nueba earthquake. However, the alert was on 0.6 sec before the arrival of the S-wave at the nearest city of Eilat ~100 km from the epicenter. This was due to the significant latencies (2-4 sec) and long data packets (up to 10 sec) that exist for the ISN which has still to be optimized for EEWS.

  9. Canadian Seismic Agreement

    SciTech Connect

    Wetmiller, R.J.; Lyons, J.A.; Shannon, W.E.; Munro, P.S.; Thomas, J.T.; Andrew, M.D.; Lapointe, S.P.; Lamontagne, M.; Wong, C.; Anglin, F.M.; Adams, J.; Cajka, M.G.; McNeil, W.; Drysdale, J.A. )

    1992-05-01

    This is a progress report of work carried out under the terms of a research agreement entitled the Canadian Seismic Agreement'' between the US Nuclear Regulatory Commission (USNRC), the Canadian Commercial Corporation and the Geophysics Division of the Geological Survey of Canada (GD/GSC) during the period from July 01, 1989 to June 30, 1990. The Canadian Seismic Agreement'' supports generally the operation of various seismograph stations in eastern Canada and the collection and analysis of earthquake data for the purpose of mitigating seismic hazards in eastern Canada and the northeastern US. The specific activities carried out in this one-year period are summarized below under four headings; Eastern Canada Telemetred Network and local network developments, Datalab developments, strong-motion network developments and earthquake activity. During this period the first surface fault unequivocably determined to have accompanied a historic earthquake in eastern North America, occurred in northern Quebec.

  10. 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

  11. Canadian seismic agreement

    SciTech Connect

    Wetmiller, R.J.; Lyons, J.A.; Shannon, W.E.; Munro, P.S.; Thomas, J.T.; Andrew, M.D.; Lamontagne, M.; Wong, C.; Anglin, F.M.; Plouffe, M.; Adams, J.; Drysdale, J.A. . Geophysics Div.)

    1990-04-01

    During the period of this report, the contract resources were spent on operation and maintenance of the Eastern Canada Telemetred Network (ECTN), development of special purpose local network systems, servicing and maintenance of the strong-motion seismograph network in eastern Canada, operation of the Ottawa data lab and earthquake monitoring and reporting. Of special note in this period was the final completion of the Sudbury (SLTN) and Charlevoix (CLTN) local networks and the integration of their data processing and analysis requirements in the regular analysis stream for ECTN data. These networks now acquire high quality digital data for detailed analysis of seismic activity and source properties from these two areas, thus effectively doubling the amount of seismic data being received by the Ottawa data lab. 37 refs., 17 figs., 2 tabs.

  12. 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.

  13. Integrated Verification Experiment data collected as part of the Los Alamos National Laboratory`s Source Region Program. Appendix C, Infrasonic measurements of IVE events: Los Alamos Source Region Program

    SciTech Connect

    Whitaker, R.W.; Noel, S.D.

    1992-12-01

    The summary report by Tom Weaver gives the overall background for the series of IVE (Integrated Verification Experiment) experiments including information on the full set of measurements made. This appendix presents details of the infrasound data for the and discusses certain aspects of a few special experiments. Prior to FY90, the emphasis of the Infrasound Program was on underground nuclear test (UGT) detection and yield estimation. During this time the Infrasound Program was a separate program at Los Alamos, and it was suggested to DOE/OAC that a regional infrasound network be established around NTS. The IVE experiments took place in a time frame that allowed simultaneous testing of possible network sites and examination of propagation in different directions. Whenever possible, infrasound stations were combined with seismic stations so that a large number could be efficiently fielded. The regional infrasound network was not pursued by DOE, as world events began to change the direction of verification toward non-proliferation. Starting in FY90 the infrasound activity became part of the Source Region Program which has a goal of understanding how energy is transported from the UGT to a variety of measurement locations.

  14. From Seismic Characterization to Coupled Process Testing Along Drifts at LSBB as an Example of Establishing an International Facility for a Worldwide Network of Underground Research Laboratories

    NASA Astrophysics Data System (ADS)

    Gaffet, S.; Wang, J. S.

    2009-12-01

    The Laboratoire Souterrain à Bas Bruit (LSBB) at Rustrel France is a French National Instrumented Infrastructure, CNRS, dedicated to inter-Disciplinary Underground Science and Technology. The underground galleries and the surrounding carbonate rock formations are well characterized by seismic imaging studies obtained with sensors both along the ridges and underground along the drifts. The facility is horizontally accessible with the main tunnel following an L-shape. The deepest is 518m below the surface. The main tunnel continues with a long gallery below the ridge, and ends with an escape shaft to the surface. Electrical and fiber optic communication cables connect the galleries and the underground to the huts on the surface. All data from LSBB are distributed on line (http://lsbb.oca.eu) and data from the 3D broadband seismic array are fed in real time (delay of ~4s) to the European Union seismic network (see streams RUSF_01, 03, 04, 05, 06, and 07 at http://www.orfeus-eu.org/Data-info/orbstats.html). Concurrently with establishing the seismic network, the LSBB characterizes its low noise environment, including its low ambient magnetic noise with a (SQUID)2 magnetometer, located 518m below the surface in a shielded cage. The magnetic noise floor in the cage is lower than 2fT/SQRT(Hz). Together with the seismic network and the magnetic sensor, tiltmeters, radiation sensors, groundwater pressure and chemistry monitoring devices are installed to characterize the unsaturated environment along the tunnel. Seasonal seepage observations are also collected. 3 national research projects are currently carried out along dedicated tunnels: (1) the project on High-Pulse Poroelasticity Protocol (HPPP) for geophysical monitoring of CO2 injection in reservoirs (http://hppp.unice.fr/), focusing currently on hydromechanical testing in carbonate rock; (2) the MAXWELL electromagnetic project on broadband imaging which employs joint resistivity and permittivity inversion (http

  15. 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.

  16. RFQ development at Los Alamos

    SciTech Connect

    Wangler, T.P.; Crandall, K.R.; Stokes, R.H.

    1982-01-01

    The basic principles of the radio-frequency quadrupole (RFQ) linac are reviewed and a summary of past and present Los Alamos work is presented. Some beam-dynamics effects, important for RFQ design, are discussed. A design example is shown for xenon and a brief discussion of low-frequency RFQ structures is given.

  17. Seismic databases of The Caucasus

    NASA Astrophysics Data System (ADS)

    Gunia, I.; Sokhadze, G.; Mikava, D.; Tvaradze, N.; Godoladze, T.

    2012-12-01

    The Caucasus is one of the active segments of the Alpine-Himalayan collision belt. The region needs continues seismic monitoring systems for better understanding of tectonic processes going in the region. Seismic Monitoring Center of Georgia (Ilia State University) is operating the digital seismic network of the country and is also collecting and exchanging data with neighboring countries. The main focus of our study was to create seismic database which is well organized, easily reachable and is convenient for scientists to use. The seismological database includes the information about more than 100 000 earthquakes from the whole Caucasus. We have to mention that it includes data from analog and digital seismic networks. The first analog seismic station in Georgia was installed in 1899 in the Caucasus in Tbilisi city. The number of analog seismic stations was increasing during next decades and in 1980s about 100 analog stations were operated all over the region. From 1992 due to political and economical situation the number of stations has been decreased and in 2002 just two analog equipments was operated. New digital seismic network was developed in Georgia since 2003. The number of digital seismic stations was increasing and in current days there are more than 25 digital stations operating in the country. The database includes the detailed information about all equipments installed on seismic stations. Database is available online. That will make convenient interface for seismic data exchange data between Caucasus neighboring countries. It also makes easier both the seismic data processing and transferring them to the database and decreases the operator's mistakes during the routine work. The database was created using the followings: php, MySql, Javascript, Ajax, GMT, Gmap, Hypoinverse.

  18. Frequency response of the USGS short period telemetered seismic system and its suitability for network studies of local earthquakes

    USGS Publications Warehouse

    Eaton, Jerry P.

    1977-01-01

    The USGS telemetered seismic system was intended primarily to record small to moderate earthquakes (magnitude 0 to 4) at distances of a few km to several hundred km. Its frequency response is such that the recorded background noise at a moderately quite Coast Range site has a relatively flat 'record' spectrum from about 1/3 Hz to about 20 Hz. With the system magnification set so that the background noise is clearly recorded (about 1 mm peak-to-peak) one can anticipate that any seismic signal that exceeds background noise appreciably in this spectral region will be large enough to be seen on the seismogram. This response represents the highest sensitivity and broadest bandwidth that we were able to attain with a 1-Hz seismometer, a simple amplifier VCO employing very low-power integrated circuits, and an 8-channel constant-bandwidth FM subcarrier multiplex system for use with commercial voice-grade phone lines.

  19. Hanford quarterly seismic monitoring report 96C

    SciTech Connect

    Reidel, S.P.

    1996-09-24

    Seismic monitoring at the Hanford Site was established in 1969 by the United States Geological Survey (USGS) under a contract with the U.S. Atomic Energy Commission. In 1975 the University of Washington assumed responsibility for and expanded the network. In 1979 the Basalt Waste Isolation Program (BWIP) became responsible for collecting seismic data for the site as part of site characterization. Rockwell International Operations followed by Westinghouse Hanford Company (WHC), Geosciences Group, operated the local network and were the contract technical advisors for the Eastern Washington Regional Network operated by the University of Washington. Funding ended for BWIP in December 1988. Seismic Monitoring and the University of Washington contract was then transferred WHC`s Environmental Division. Seismic Monitoring is currently assigned to WHC`s Hanford Technical Services (HTS), part of the Environmental Division. The Seismic Monitoring Analysis and Repair Team (SMART) operates, maintains, and analyzes data from the Hanford Seismic Network (HSN), extending the site historical seismic database and fulfilling U.S. Department of Energy, Richland Operations Office requirements and orders. The Seismic Monitoring Analysis and Repair Team also maintains the Eastern Washington Regional Network (EWRN). The University of Washington uses the data from the EWRN and other seismic networks in the Northwest to provide the SMART with necessary regional input for the seismic hazards analysis at the Hanford Site.

  20. Joint Interpretation of Multi-parameter Tomographic Models (e.g., Seismic P and S Velocity, Anisotropy, Attenuation): A Neural Network Approach

    NASA Astrophysics Data System (ADS)

    Bauer, K.

    2008-12-01

    Seismic tomography can provide a set of models which represent different properties of the same target region. A typical example is the development of coincident P and S velocity cross sections from travel time tomography. Other applications may include additional determination of attenuation and anisotropy. Self-organizing maps (SOM) are powerful neural network techniques to classify and interpret multi-attribute data sets. The coincident tomographic images are translated to a set of data vectors in order to train a Kohonen layer. The total gradient of the model vectors is determined for the trained SOM and a watershed segmentation algorithm is used to visualize and map the lithological clusters with well-defined seismic signatures. The principal working flow is demonstrated for a synthetic data set. Further examples include P and S velocity tomography across a sub-volcanic ring complex in Namibia, and combination of velocity, anisotropy, and attenuation tomography to characterize gas hydrate bearing sediments in the Mackenzie Delta, NW Canada.

  1. Proterozoic structure, cambrian rifting, and younger faulting as revealed by a regional seismic reflection network in the Southern Illinois Basin

    USGS Publications Warehouse

    Potter, C.J.; Drahovzal, J.A.; Sargent, M.L.; McBride, J.H.

    1997-01-01

    Four high-quality seismic reflection profiles through the southern Illinois Basin, totaling 245 km in length, provide an excellent regional subsurface stratigraphic and structural framework for evaluation of seismic risk, hydrocarbon occurrence, and other regional geologic studies. These data provide extensive subsurface information on the geometry of the intersection of the Cambrian Reelfoot and Rough Creek rifts, on extensive Proterozoic reflection sequences, and on structures (including the Fluorspar Area Fault Complex and Hicks Dome) that underlie a transitional area between the well-defined New Madrid seismic zone (to the southwest) and a more diffuse area of seismicity in the southern Illinois Basin. Our principal interpretations from these data are listed here in order of geologic age, from oldest to youngest: 1. Prominent Proterozoic layering, possibly equivalent to Proterozoic (???1 Ga) Middle Run Formation clastic strata and underlying (1.3-1.5 Ga) volcanic rocks of the East Continent rift basin, has been strongly deformed, probably as part of the Grenville foreland fold and thrust belt. 2. A well-defined angular unconformity is seen in many places between Proterozoic and Cambrian strata; a post-Grenville Proterozoic sequence is also apparent locally, directly beneath the base of the Cambrian. 3. We infer a major reversal in Cambrian rift polarity (accommodation zone) in the Rough Creek Graben in western Kentucky. 4. Seismic facies analysis suggests the presence of basin-floor fan complexes at and near the base of the Cambrian interval and within parts of a Proterozoic post-Grenville sequence in several parts of the Rough Creek Graben. 5. There is an abrupt pinchout of the Mount Simon Sandstone against crystalline basement beneath the Dale Dome (near the Texaco no. 1 Cuppy well, Hamilton County) in southeastern Illinois, and a more gradual Mount Simon pinchout to the southeast. 6. Where crossed by the seismic reflection line in southeast Illinois, some

  2. Monitoring the instrument response of the high-sensitivity seismograph network in Japan (Hi-net): effects of response changes on seismic interferometry analysis

    NASA Astrophysics Data System (ADS)

    Ueno, Tomotake; Saito, Tatsuhiko; Shiomi, Katsuhiko; Haryu, Yoshikatsu

    2015-08-01

    More than 10 years have passed since observations began to be recorded by Hi-net, a network of high-sensitivity seismometers located in Japan. Several large earthquakes, including the 2011 Tohoku-Oki earthquake, have been recorded by the network during this period. Age-related degradation and the strong ground motion of large earthquakes may change the instrument response of the high-sensitivity seismometers of Hi-net. Thus, we checked the natural frequency f and damping constant h for each Hi-net sensor and monitored the instrument response for 10 years from 2003 to 2013. Most of the sensors showed a stable instrument response over this period. More than 95 % of the sensors whose responses we could well estimate showed small fluctuations in their natural frequencies and damping constants of within 0.05 Hz and 0.05, respectively. We also found that many Hi-net sensors in northeastern Japan showed slight changes in the instrument response as a result of the 2011 Tohoku-Oki earthquake. Based on the assumption that the instrument responses remained unchanged, the fractional velocity reduction in the subsurface structure was reported by seismic interferometry analysis. To investigate how changes in the instrument response can cause errors in seismic interferometry analysis, we conducted a synthetic test. The results indicate that the instrument response did not result in systematic variation in the time delay observed in the interferometry analysis. This confirmed that the velocity decrease observed as a result of the 2011 Tohoku-Oki earthquake was not due to artificial instrument error.

  3. RFQ development at Los Alamos

    SciTech Connect

    Armstrong, D.D.; Cornelius, W.D.; Purser, F.O.; Jameson, R.A.; Wangler, T.P.

    1984-01-01

    We report recent progress on the two radio-frequency quadrupole (RFQ) structures being developed at Los Alamos. First, we report on the second 425-MHz RFQ for H/sup -/ acceleration, which is being built in a research effort to understand and further develop the RFQ. Second, we discuss progress on the 80-MHz cw RFQ for deuterons, which is being built for the Fusion Materials Irradiation Test (FMIT) facility.

  4. The MeSO-net (Metropolitan Seismic Observation network) confronts the Pacific Coast of Tohoku Earthquake, Japan (Mw 9.0)

    NASA Astrophysics Data System (ADS)

    Kasahara, K.; Nakagawa, S.; Sakai, S.; Nanjo, K.; Panayotopoulos, Y.; Morita, Y.; Tsuruoka, H.; Kurashimo, E.; Obara, K.; Hirata, N.; Aketagawa, T.; Kimura, H.

    2011-12-01

    On April 2007, we have launched the special project for earthquake disaster mitigation in the Tokyo Metropolitan area (Fiscal 2007-2011). As a part of this project, construction of the MeSO-net (Metropolitan Seismic Observation network) has been completed, with about 300 stations deployed at mainly elementary and junior-high schools with an interval of about 5 km in space. This results in a highly dense network that covers the metropolitan area. To achieve stable seismic observation with lower surface ground noise, relative to a measurement on the surface, sensors of all stations were installed in boreholes at a depth of about 20m. The sensors have a wide dynamic range (135dB) and a wide frequency band (DC to 80Hz). Data are digitized with 200Hz sampling and telemetered to the Earthquake Research Institute, University of Tokyo. The MeSO-net that can detect and locate most earthquakes with magnitudes above 2.5 provides a unique baseline in scientific and engineering researches on the Tokyo metropolitan area, as follows. One of the main contributions is to greatly improve the image of the Philippine Sea plate (PSP) (Nakagawa et al., 2010) and provides an accurate estimation of the plate boundaries between the PSP and the Pacific plate, allowing us to possibly discuss clear understanding of the relation between the PSP deformation and M7+ intra-slab earthquake generation. Also, the latest version of the plate model in the metropolitan area, proposed by our project, attracts various researchers, comparing with highly-accurate solutions of fault mechanism, repeating earthquakes, etc. Moreover, long-periods ground motions generated by the 2011 earthquake off the Pacific coast of Tohoku earthquake (Mw 9.0) were observed by the MeSO-net and analyzed to obtain the Array Back-Projection Imaging of this event (Honda et al., 2011). As a result, the overall pattern of the imaged asperities coincides well with the slip distribution determined based on other waveform inversion

  5. Tomography of the subducting Cocos plate in central Mexico using data from the installation of a prototype wireless seismic network: Images of a truncated slab

    NASA Astrophysics Data System (ADS)

    Husker, Allen Leroy, Jr.

    The central Mexican subduction zone exhibits an oblique strike of the volcanic arc, the Trans-Mexican Volcanic Belt (TMVB), with respect to the trench, flat-slab subduction, and has no Wadati-Benioff zone. The oblique strike of the TMVB is explained by the changing rate of subduction at the trench. The shape of the slab beyond the flat slab section has been unknown until now due to a lack of seismicity, but inferred by the position of the volcanic arc. Here we use data from the Middle America Seismic Experiment (MASE) to image the slab both with tomography and inverting for a slab temperature model. MASE is a collaboration between the Center for Embedded Networked Sensing (CENS) at UCLA, the Universidad Nacional Autonoma de Mexico (UNAM), and the California Institute of Technology (CIT). The data used in this study was from the MASE seismic network. It consisted of 100 seismic stations running, in a line, every 5-6 km from Acapulco, north through TMVB, and to almost the Gulf of Mexico. Half of the seismic stations were the typical standalone style station. These stations were visited once a month to change memory disks and for maintenance. The other 50 stations were developed to send data wirelessly through the network to a base station where the data is linked to the Internet. The 50 stations, called the Wirelessly Linked Seismological Network (WiLSoN), utilize standard Internet tools and protocols to make it both robust and portable to other systems. WiLSoN is described and compared to the standalone stations. The time to permit and install WiLSoN was double that of the standalone network. However, the benefits of WiLSoN included near real-time data and knowledge of system health as compared to only once a month visits to collect data from the standalone stations. However, the data collected from the standalone sites was more complete than that collected from WiLSoN. The lack of data completeness is attributed to the development of both software and hardware for

  6. Upgrade of the Los Alamos Plutonium Facility control system

    SciTech Connect

    Pope, N.G.; Turner, W.J.; Brown, R.E.; Bibeau, R.A.; Davis, R.R.; Hogan, K.

    1996-05-01

    After 20 yrs service, the Los Alamos Plutonium Facility is undergoing an upgrade to its aging Facility Control System. The new system design includes a network of redundantly-paired programmable logic controllers that will interface with about 2200 field data points. The data communications network that has been designed includes a redundant, self-healing fiber optic data highway as well as a fiber optic ethernet. Commercially available human-machine interface software running on a UNIX-based system displays facility subsystem status operator X-terminals. Project design features, methods, costs, and schedule are discussed.

  7. LANL seismic screening method for existing buildings

    SciTech Connect

    Dickson, S.L.; Feller, K.C.; Fritz de la Orta, G.O.

    1997-01-01

    The purpose of the Los Alamos National Laboratory (LANL) Seismic Screening Method is to provide a comprehensive, rational, and inexpensive method for evaluating the relative seismic integrity of a large building inventory using substantial life-safety as the minimum goal. The substantial life-safety goal is deemed to be satisfied if the extent of structural damage or nonstructural component damage does not pose a significant risk to human life. The screening is limited to Performance Category (PC) -0, -1, and -2 buildings and structures. Because of their higher performance objectives, PC-3 and PC-4 buildings automatically fail the LANL Seismic Screening Method and will be subject to a more detailed seismic analysis. The Laboratory has also designated that PC-0, PC-1, and PC-2 unreinforced masonry bearing wall and masonry infill shear wall buildings fail the LANL Seismic Screening Method because of their historically poor seismic performance or complex behavior. These building types are also recommended for a more detailed seismic analysis. The results of the LANL Seismic Screening Method are expressed in terms of separate scores for potential configuration or physical hazards (Phase One) and calculated capacity/demand ratios (Phase Two). This two-phase method allows the user to quickly identify buildings that have adequate seismic characteristics and structural capacity and screen them out from further evaluation. The resulting scores also provide a ranking of those buildings found to be inadequate. Thus, buildings not passing the screening can be rationally prioritized for further evaluation. For the purpose of complying with Executive Order 12941, the buildings failing the LANL Seismic Screening Method are deemed to have seismic deficiencies, and cost estimates for mitigation must be prepared. Mitigation techniques and cost-estimate guidelines are not included in the LANL Seismic Screening Method.

  8. Seismic Vulnerability Assessment Waste Characterization Reduction and Repackaging Building, TA-50-69

    SciTech Connect

    M.W.Sullivan; J.Ruminer; I.Cuesta

    2003-02-02

    This report presents the results of the seismic structural analyses completed on the Waste Characterization Reduction and Repackaging (WCRR) Building in support of ongoing safety analyses. WCRR is designated as TA-50-69 at Los Alamos National Laboratory, Los Alamos, New Mexico. The facility has been evaluated against Department of Energy (DOE) seismic criteria for Natural Phenomena Hazards (NPH) Performance Category II (PC 2). The seismic capacities of two subsystems within the WCRR building, the material handling glove box and the lift rack immediately adjacent to the Glove Box are also documented, and the results are presented.

  9. Data quality of seismic records from the Tohoku, Japan earthquake as recorded across the Albuquerque Seismological Laboratory networks

    USGS Publications Warehouse

    Ringler, A.T.; Gee, L.S.; Marshall, B.; Hutt, C.R.; Storm, T.

    2012-01-01

    Great earthquakes recorded across modern digital seismographic networks, such as the recent Tohoku, Japan, earthquake on 11 March 2011 (Mw = 9.0), provide unique datasets that ultimately lead to a better understanding of the Earth's structure (e.g., Pesicek et al. 2008) and earthquake sources (e.g., Ammon et al. 2011). For network operators, such events provide the opportunity to look at the performance across their entire network using a single event, as the ground motion records from the event will be well above every station's noise floor.

  10. 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

  11. Earthquake source imaging by high-resolution array analysis at regional distances: the 2010 M7 Haiti earthquake as seen by the Venezuela National Seismic Network

    NASA Astrophysics Data System (ADS)

    Meng, L.; Ampuero, J. P.; Rendon, H.

    2010-12-01

    Back projection of teleseismic waves based on array processing has become a popular technique for earthquake source imaging,in particular to track the areas of the source that generate the strongest high frequency radiation. The technique has been previously applied to study the rupture process of the Sumatra earthquake and the supershear rupture of the Kunlun earthquakes. Here we attempt to image the Haiti earthquake using the data recorded by Venezuela National Seismic Network (VNSN). The network is composed of 22 broad-band stations with an East-West oriented geometry, and is located approximately 10 degrees away from Haiti in the perpendicular direction to the Enriquillo fault strike. This is the first opportunity to exploit the privileged position of the VNSN to study large earthquake ruptures in the Caribbean region. This is also a great opportunity to explore the back projection scheme of the crustal Pn phase at regional distances,which provides unique complementary insights to the teleseismic source inversions. The challenge in the analysis of the 2010 M7.0 Haiti earthquake is its very compact source region, possibly shorter than 30km, which is below the resolution limit of standard back projection techniques based on beamforming. Results of back projection analysis using the teleseismic USarray data reveal little details of the rupture process. To overcome the classical resolution limit we explored the Multiple Signal Classification method (MUSIC), a high-resolution array processing technique based on the signal-noise orthognality in the eigen space of the data covariance, which achieves both enhanced resolution and better ability to resolve closely spaced sources. We experiment with various synthetic earthquake scenarios to test the resolution. We find that MUSIC provides at least 3 times higher resolution than beamforming. We also study the inherent bias due to the interferences of coherent Green’s functions, which leads to a potential quantification

  12. Seismic Monitoring for the United Arab Emirates

    SciTech Connect

    Rodgers, A; Nakanishi, K

    2005-04-11

    There is potential for earthquakes in the United Arab Emirates and in the Zagros mountains to cause structural damage and pose a threat to safety of people. Damaging effects from earthquakes can be mitigated by knowledge of the location and size of earthquakes, effects on construction, and monitoring these effects over time. Although a general idea of seismicity in the UAE may be determined with data from global seismic networks, these global networks do not have the sensitivity to record smaller seismic events and do not have the necessary accuracy to locate the events. A National Seismic Monitoring Observatory is needed for the UAE that consists of a modern seismic network and a multidisciplinary staff that can analyze and interpret the data from the network. A seismic network is essential to locate earthquakes, determine event magnitudes, identify active faults and measure ground motions from earthquakes. Such a network can provide the data necessary for a reliable seismic hazard assessment in the UAE. The National Seismic Monitoring Observatory would ideally be situated at a university that would provide access to the wide range of disciplines needed in operating the network and providing expertise in analysis and interpretation.

  13. Airport-Noise Levels and Annoyance Model (ALAMO) user's guide

    NASA Technical Reports Server (NTRS)

    Deloach, R.; Donaldson, J. L.; Johnson, M. J.

    1986-01-01

    A guide for the use of the Airport-Noise Level and Annoyance MOdel (ALAMO) at the Langley Research Center computer complex is provided. This document is divided into 5 primary sections, the introduction, the purpose of the model, and an in-depth description of the following subsystems: baseline, noise reduction simulation and track analysis. For each subsystem, the user is provided with a description of architecture, an explanation of subsystem use, sample results, and a case runner's check list. It is assumed that the user is familiar with the operations at the Langley Research Center (LaRC) computer complex, the Network Operating System (NOS 1.4) and CYBER Control Language. Incorporated within the ALAMO model is a census database system called SITE II.

  14. 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.

  15. Los Alamos Science: Number 16

    SciTech Connect

    Cooper, N.G.

    1988-01-01

    It was an unusually stimulating day and a half at Los Alamos when two Nobel Laureates in physiology, a leading paleontologist, and a leading bio-astrophysicist came together to discuss ''Unsolved Problems in the Science of Life,'' the topic of the second in a series of special meetings sponsored by the Fellows of the Laboratory. Just like the first one on ''Creativity in Science,'' this colloquium took us into a broader arena of ideas and viewpoints than is our usual daily fare. To contemplate the evolution and mysteries of intelligent life from the speakers' diverse points of view at one time, in one place was indeed a rare experience.

  16. 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

  17. 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.

  18. Seismic background noise at the Norwegian Regional Seismic Array

    SciTech Connect

    Breding, D.R.

    1987-10-01

    The System Control and Receiving Station (SCARS) has been collecting spectral history data on the Regional Seismic Test Network (RSTN) since 1981 and on the Norwegian Regional Seismic Array (NRSA) since it was installed in 1984. This report details the spectral history data for the NRSA through 1986. The appendix contains spectral history data for all five RSTN stations from the time they were installed until their deactivation in September 1986.

  19. Seismic monitoring of Poland - temporary seismic project - first results

    NASA Astrophysics Data System (ADS)

    Trojanowski, J.; Plesiewicz, B.; Wiszniowski, J.; Suchcicki, J.; Tokarz, A.

    2012-04-01

    The aim of the project is to develop national database of seismic activity for seismic hazard assessment. Poland is known as a region of very low seismicity, however some earthquakes occur from time to time. The historical catalogue consists of less than one hundred earthquakes in the time span of almost one thousand years. Due to such a low occurrence rate, the study has been focussing on events at magnitudes lower than 2 which are more likely to occur during a few-year-long project. There are 24 mobile seismic stations involved in the project which are deployed in temporary locations close to humans neighbourhood. It causes a high level of noise and disturbances in recorded seismic signal. Moreover, the majority of Polish territory is covered by a thick sediments. It causes the problem of a reliable detection method for small seismic events in noisy data. The majority of algorithms is based on the concept of STA/LTA ratio and is designed for strong teleseismic events registered on many stations. Unfortunately they fail on the problem of weak events in the signal with noise and disturbances. It has been decided to apply Real Time Recurrent Neural Network (RTRN) to detect small natural seismic events from Poland. This method is able to assess relations of seismic signal in frequency domains as well as in time of seismic phases. The RTRN was taught by wide range of seismic signals - regional, teleseismic as well as blasts. The method is routinely used to analyse data from the project. In the firs two years of the project the seismic network was set in southern Poland, where relatively large seismicity in known. Since the mid-2010 the stations have been working in several regions of central and northern Poland where some minor historical earthquakes occurred. Over one hundred seismic events in magnitude range from 0.5 to 2.3 confirms the activity of Podhale region (Tatra Mountains, Carpathians), where an earthquake of magnitude 4.3 occurred in 2004. Initially three

  20. A new interpretation of seismic tomography in the southern Dead Sea basin using neural network clustering techniques

    NASA Astrophysics Data System (ADS)

    Braeuer, Benjamin; Bauer, Klaus

    2015-11-01

    The Dead Sea is a prime location to study the structure and development of pull-apart basins. We analyzed tomographic models of Vp, Vs, and Vp/Vs using self-organizing map clustering techniques. The method allows us to identify major lithologies by their petrophysical signatures. Remapping the clusters into the subsurface reveals the distribution of basin sediments, prebasin sedimentary rocks, and crystalline basement. The Dead Sea basin shows an asymmetric structure with thickness variation from 5 km in the west to 13 km in the east. Most importantly, we identified a distinct, well-defined body under the eastern part of the basin down to 18 km depth. Considering its geometry and petrophysical signature, this unit is interpreted as a buried counterpart of the shallow prebasin sediments encountered outside of the basin and not as crystalline basement. The seismicity distribution supports our results, where events are concentrated along boundaries of the basin and the deep prebasin sedimentary body. Our results suggest that the Dead Sea basin is about 4 km deeper than assumed from previous studies.

  1. Seismicity of the Jalisco Block

    NASA Astrophysics Data System (ADS)

    Nunez-Cornu, F. J.; Rutz, M.; Camarena-Garcia, M.; Trejo-Gomez, E.; Reyes-Davila, G.; Suarez-Plascencia, C.

    2002-12-01

    In April 2002 began to transmit the stations of the first phase of Jalisco Telemetric Network located at the northwest of Jalisco Block and at the area of Volcan de Fuego (Colima Volcano), in June were deployed four additional MarsLite portable stations in the Bahia de Banderas area, and by the end of August one more portable station at Ceboruco Volcano. The data of these stations jointly with the data from RESCO (Colima Telemetric Network) give us the minimum seismic stations coverage to initiate in a systematic and permanent way the study of the seismicity in this very complex tectonic region. A preliminary analysis of seismicity based on the events registered by the networks using a shutter algorithm, confirms several important features proposed by microseismicity studies carried out between 1996 and 1998. A high level of seismicity inside and below of Rivera plate is observed, this fact suggest a very complex stress pattern acting on this plate. Shallow seismicity at south and east of Bahia de Banderas also suggest a complex stress pattern in this region of the Jalisco Block, events at more than 30 km depth are located under the mouth of the bay and in face of it, a feature denominated Banderas Boundary mark the change of the seismic regime at north of this latitude (20.75°N), however some shallow events were located at the region of Nayarit.

  2. Mitigation of the consequence of seismically induced damage on a utility water network by means of next generation SCADA

    NASA Astrophysics Data System (ADS)

    Robertson, Jamie; Shinozuka, Masanobu; Wu, Felix

    2011-04-01

    When a lifeline system such as a water delivery network is damaged due to a severe earthquake, it is critical to identify its location and extent of the damage in real time in order to minimize the potentially disastrous consequence such damage could otherwise entail. This paper demonstrates how the degree of such minimization can be estimated qualitatively by using the water delivery system of Irvine Water Ranch District (IRWD) as testbed, when it is subjected to magnitude 6.6 San Joaquin Hills Earthquake. In this demonstration, we consider two cases when the IRWD system is equipped or not equipped with a next generation SCADA which consists of a network of MEMS acceleration sensors densely populated and optimally located. These sensors are capable of identifying the location and extent of the damage as well as transmitting the data to the SCADA center for monitoring and control.

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

    NASA Astrophysics Data System (ADS)

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

    2003-04-01

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

  4. Constraining shallow slip and tsunami excitation in megathrust ruptures using seismic and ocean acoustic waves recorded on ocean-bottom sensor networks

    NASA Astrophysics Data System (ADS)

    Kozdon, Jeremy E.; Dunham, Eric M.

    2014-06-01

    Great earthquakes along subduction-zone plate boundaries, like the 2011 magnitude 9.0 Tohoku-Oki, Japan, event, deform the seafloor to generate massive tsunamis. Tsunami wave heights near shore are greatest when excitation occurs far offshore near the trench, where water depths are greatest and fault slip is shallow. The Tohoku event, featuring over 30 m of slip near the trench, exemplifies this hazard. Unfortunately the rupture process that far offshore is poorly constrained with land-based geodetic and even most seafloor deformation measurements, and seismic inferences of shallow slip are often nonunique. Here we demonstrate, through dynamic rupture simulations of the Tohoku event, that long-period guided waves in the ocean (specifically, leaking oceanic P-wave modes known as PL waves) can resolve the shallow rupture process and tsunami excitation near the trench. With predicted pressure changes of ∼0.1-1 MPa along most of the seafloor landward of the trench, and periods of several seconds, these PL waves should be observable with ocean-bottom pressure sensors and/or seismometers. With cabled sensor networks like those being deployed offshore Japan and in other subduction zones, these waves could be used to rapidly quantify shallow slip and near-trench seafloor uplift and improve local tsunami early warning systems.

  5. Los Alamos PC estimating system

    SciTech Connect

    Stutz, R.A.; Lemon, G.D.

    1987-01-01

    The Los Alamos Cost Estimating System (QUEST) is being converted to run on IBM personal computers. This very extensive estimating system is capable of supporting cost estimators from many different and varied fields. QUEST does not dictate any fixed method for estimating. QUEST supports many styles and levels of detail estimating. QUEST can be used with or without data bases. This system allows the estimator to provide reports based on levels of detail defined by combining work breakdown structures. QUEST provides a set of tools for doing any type of estimate without forcing the estimator to use any given method. The level of detail in the estimate can be mixed based on the amount of information known about different parts of the project. The system can support many different data bases simultaneously. Estimators can modify any cost in any data base.

  6. Statistical models for seismic magnitude

    NASA Astrophysics Data System (ADS)

    Christoffersson, Anders

    1980-02-01

    In this paper some statistical models in connection with seismic magnitude are presented. Two main situations are treated. The first deals with the estimation of magnitude for an event, using a fixed network of stations and taking into account the detection and bias properties of the individual stations. The second treats the problem of estimating seismicity, and detection and bias properties of individual stations. The models are applied to analyze the magnitude bias effects for an earthquake aftershock sequence from Japan, as recorded by a hypothetical network of 15 stations. It is found that network magnitudes computed by the conventional averaging technique are considerably biased, and that a maximum likelihood approach using instantaneous noise-level estimates for non-detecting stations gives the most consistent magnitude estimates. Finally, the models are applied to evaluate the detection characteristics and associated seismicity as recorded by three VELA arrays: UBO (Uinta Basin), TFO (Tonto Forest) and WMO (Wichita Mountains).

  7. Seismicity of southern Lake Tanganyika

    NASA Astrophysics Data System (ADS)

    Lavayssiere, A.; Gallacher, R. J.; Keir, D.; Ebinger, C. J.; Drooff, C.; Khalfan, M.; Bull, J. M.

    2015-12-01

    Global seismic networks document frequent and unusually deep earthquakes in East African rift sectors lacking central volcanoes. The deep seismicity means that we can use earthquakes to probe the geometry and kinematics of fault systems throughout the crust, and to understand the distribution of strain between large offset border fault systems and intrabasinal faults. The southern Tanganyika rift zone has the highest seismicity rate within East Africa during the period 1973-present, yet earlier temporary seismometer networks have been too sparse in space and time to relocate earthquakes with location and depth errors of < 5-10 km. We address this issue by recording seismicity of southern Lake Tanganyika since June 2014 using a network at 12 broadband seismic stations. The distribution of earthquakes shows that deformation primarily occurs on large offset border faults beneath the lake. Subsidiary earthquake activity occurs along the subparrallel Rukwa graben, and beneath the NE-SW striking Mweru rift. The distribution of earthquakes suggests the southern end of lake Tanganyika is characterized by a network of intersecting NNW and NE striking faults. The depths of earthquakes are distributed throughout the crust, consistent with the relatively strong lithosphere.

  8. Seismic signals from asymmetric underground nuclear explosions

    SciTech Connect

    Davis, C.G.

    1993-09-01

    The methods discussed to estimate the effect on the seismic signals from asymmetric underground nuclear explosions, depends on the use of large-scale numerical codes and high-speed computers. The use of a two-dimensional (2D) radiation diffusion coupled Eulerian hydrodynamic code (SOIL) for the early time phenomenology is discussed. The results from this calculation are then coupled into a 2D Lagrangian code that treats the strength of the materials and the effects of fractures, ground reflections and spells. The final step in the simulation is the use of a seismic code (which uses the representation theory) to develop the actual far field seismic signals. These calculations were run on the CRAY YMP computers at the Los Alamos National Laboratory.

  9. Using synthetic kinematic source inversions with dynamic rupture models to evaluate the effect of seismic network density and geometry in near-field source inversions

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Dalguer, L. A.; Song, S.; Clinton, J. F.

    2013-12-01

    Detailed source imaging of the spatial and temporal slip distribution of earthquakes is a main research goal for seismology. In this study we investigate how the number and geometrical distribution of seismic stations affect finite kinematic source inversion results by inverting ground motions derived from a known synthetic dynamic earthquake rupture model, which is governed by the slip weakening friction law with heterogeneous stress distribution. Our target dynamic rupture model is a buried strike-slip event (Mw 6.5) in a layered half space (Dalguer & Mai, 2011) with broadband synthetic ground motions created at 168 near-field stations. In the inversion, we modeled low frequency (under 1Hz) waveforms using a genetic algorithm in a Bayesian framework (Moneli et al. 2008) to retrieve peak slip velocity, rupture time, and rise time of the source. The dynamic consistent regularized Yoffe function (Tinti et al. 2005) was applied as a single window slip velocity function. Tikhonov regularization was used to smooth final slip. We tested three station network geometry cases: (a) single station, in which we inverted 3 component waveforms from a single station varying azimuth and epicentral distance; (b) multi-station configurations with similar numbers of stations all at similar distances from, but regularly spaced around the fault; (c) irregular multi-station configurations using different numbers of stations. For analysis, waveform misfits are calculated using all 168 stations. Our results show: 1) single station tests suggest that it may be possible to obtain a relatively good source model even using one station, with a waveform misfit comparable to that obtained with the best source model. The best single station performance occurs with stations in which amplitude ratios between the three components are not large, indicating that P & S waves are all present. We infer that both body wave radiation pattern and distance play an important role in selection of optimal

  10. Earthquake Early Warning: Real-time Testing of an On-site Method Using Waveform Data from the Southern California Seismic Network

    NASA Astrophysics Data System (ADS)

    Solanki, K.; Hauksson, E.; Kanamori, H.; Wu, Y.; Heaton, T.; Boese, M.

    2007-12-01

    We have implemented an on-site early warning algorithm using the infrastructure of the Caltech/USGS Southern California Seismic Network (SCSN). We are evaluating the real-time performance of the software system and the algorithm for rapid assessment of earthquakes. In addition, we are interested in understanding what parts of the SCSN need to be improved to make early warning practical. Our EEW processing system is composed of many independent programs that process waveforms in real-time. The codes were generated by using a software framework. The Pd (maximum displacement amplitude of P wave during the first 3sec) and Tau-c (a period parameter during the first 3 sec) values determined during the EEW processing are being forwarded to the California Integrated Seismic Network (CISN) web page for independent evaluation of the results. The on-site algorithm measures the amplitude of the P-wave (Pd) and the frequency content of the P-wave during the first three seconds (Tau-c). The Pd and the Tau-c values make it possible to discriminate between a variety of events such as large distant events, nearby small events, and potentially damaging nearby events. The Pd can be used to infer the expected maximum ground shaking. The method relies on data from a single station although it will become more reliable if readings from several stations are associated. To eliminate false triggers from stations with high background noise level, we have created per station Pd threshold configuration for the Pd/Tau-c algorithm. To determine appropriate values for the Pd threshold we calculate Pd thresholds for stations based on the information from the EEW logs. We have operated our EEW test system for about a year and recorded numerous earthquakes in the magnitude range from M3 to M5. Two recent examples are a M4.5 earthquake near Chatsworth and a M4.7 earthquake near Elsinore. In both cases, the Pd and Tau-c parameters were determined successfully within 10 to 20 sec of the arrival of the

  11. Seismic sequences in the Sombrero Seismic Zone

    NASA Astrophysics Data System (ADS)

    Pulliam, J.; Huerfano, V. A.; ten Brink, U.; von Hillebrandt, C.

    2007-05-01

    The northeastern Caribbean, in the vicinity of Puerto Rico and the Virgin Islands, has a long and well-documented history of devastating earthquakes and tsunamis, including major events in 1670, 1787, 1867, 1916, 1918, and 1943. Recently, seismicity has been concentrated to the north and west of the British Virgin Islands, in the region referred to as the Sombrero Seismic Zone by the Puerto Rico Seismic Network (PRSN). In the combined seismicity catalog maintained by the PRSN, several hundred small to moderate magnitude events can be found in this region prior to 2006. However, beginning in 2006 and continuing to the present, the rate of seismicity in the Sombrero suddenly increased, and a new locus of activity developed to the east of the previous location. Accurate estimates of seismic hazard, and the tsunamigenic potential of seismic events, depend on an accurate and comprehensive understanding of how strain is being accommodated in this corner region. Are faults locked and accumulating strain for release in a major event? Or is strain being released via slip over a diffuse system of faults? A careful analysis of seismicity patterns in the Sombrero region has the potential to both identify faults and modes of failure, provided the aggregation scheme is tuned to properly identify related events. To this end, we experimented with a scheme to identify seismic sequences based on physical and temporal proximity, under the assumptions that (a) events occur on related fault systems as stress is refocused by immediately previous events and (b) such 'stress waves' die out with time, so that two events that occur on the same system within a relatively short time window can be said to have a similar 'trigger' in ways that two nearby events that occurred years apart cannot. Patterns that emerge from the identification, temporal sequence, and refined locations of such sequences of events carry information about stress accommodation that is obscured by large clouds of

  12. 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.

  13. 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

  14. seismicity and seismotectonics of Libya

    NASA Astrophysics Data System (ADS)

    Ben Suleman, abdunnur

    2015-04-01

    Libya, located at the central Mediterranean margin of the African shield, underwent many episodes of orogenic activity that shaped its geological setting. The present day deformation of Libya is the result of the Eurasia-Africa continental collision. The tectonic evolution of Libya has yielded a complex crustal structure that is composed of a series of basins and uplifts. This study aims to explain in detail the seismicity and seismotectonics of Libya using new data recorded by the recently established Libyan National Seismograph Network (LNSN) incorporating other available geophysical and geological information. Detailed investigations of the Libyan seismicity indicates that Libya has experienced earthquakes of varying magnitudes The seismic activity of Libya shows dominant trends of Seismicity with most of the seismic activity concentrated along the northern coastal areas. Four major clusters of Seismicity were quit noticeable. Fault plane solution was estimated for 20 earthquakes recorded by the Libyan National Seismograph Network in northwestern and northeastern Libya. Results of fault plane solution suggest that normal faulting was dominant in the westernmost part of Libya; strike slip faulting was dominant in northern-central part of Libya. The northern-eastern part of the country suggests that dip-dip faulting were more prevalent.

  15. Sunset at the ALaMO

    NASA Video Gallery

    A new color all-sky camera has opened its eyes at the ALaMO, or Automated Lunar and Meteor Observatory, at NASA's Marshall Space Flight Center in Huntsville, Ala. Watch its inaugural video below, s...

  16. Environmental surveillance at Los Alamos during 1994

    SciTech Connect

    1996-07-01

    This report describes environmental monitoring activities at Los Alamos National Laboratory for 1994. Data were collected to assess external penetrating radiation, airborne emissions, liquid effluents, radioactivity of environmental materials and food stuffs, and environmental compliance.

  17. New Rad Lab for Los Alamos

    ScienceCinema

    None

    2010-01-08

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  18. Publications of Los Alamos research 1988

    SciTech Connect

    Varjabedian, K.; Dussart, S.A.; McClary, W.J.; Rich, J.A.

    1989-12-01

    This bibliography lists unclassified publications of work done at the Los Alamos National Laboratory for 1988. The entries, which are subdivided by broad subject categories, are cross-referenced with an author index and a numeric index.

  19. New Rad Lab for Los Alamos

    SciTech Connect

    2008-08-06

    The topping out ceremony for a key construction stage in the Los Alamos National Laboratory's newest facility, the Radiological Laboratory Utility & Office Building. This is part of the National Nu...  

  20. Edward Teller Returns to LOS Alamos

    NASA Astrophysics Data System (ADS)

    Hecker, Siegfried S.

    2010-01-01

    I was asked to share some reflections of Edward Teller's return to Los Alamos during my directorship. I met Teller late in his life. My comments focus on that time and they will be mostly in the form of stories of my interactions and those of my colleagues with Teller. Although the focus of this symposium is on Teller's contributions to science, at Los Alamos it was never possible to separate Teller's science from policy and controversy ...

  1. Internship at Los Alamos National Laboratory

    SciTech Connect

    Dunham, Ryan Q.

    2012-07-11

    Los Alamos National Laboratory (LANL) is located in Los Alamos, New Mexico. It provides support for our country's nuclear weapon stockpile as well as many other scientific research projects. I am an Undergraduate Student Intern in the Systems Design and Analysis group within the Nuclear Nonproliferation division of the Global Security directorate at LANL. I have been tasked with data analysis and modeling of particles in a fluidized bed system for the capture of carbon dioxide from power plant flue gas.

  2. Los Alamos plutonium facility applied systems integration project status report for period ending August 31, 1981

    SciTech Connect

    Shirk, D.G.; Bearse, R.C.; Marshall, R.S.; Baker, A.L.; Thomas, C.C. Jr.

    1982-02-01

    The conceptual design of an on-line, near-real-time nondestructive assay instrumentation network for the Los Alamos Plutonium Facility is complete. Analysis of instrument history data indicates that the instrument certification procedures need improvement. Analysis of exhaust filter data has led to the derivation of a buildup prediction equation that is a function of throughput. This suggests that development of a generalized model is possible. A number of routine reports are now available from the Plutonium Facility/Los Alamos Safeguards System including inventories and active reports.

  3. Annual Hanford Seismic Report for Fiscal Year 2002

    SciTech Connect

    Hartshorn, Donald C.; Reidel, Steve P.; Rohay, Alan C.

    2002-11-15

    This report summarizes the earthquake activity on Hanford for FY 2002. 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 1,177 triggers during fiscal year 2002. Of these triggers, 553 were earthquakes. Two earthquakes were located in the Hanford Seismic Network area. Stratigraphically 13 occurred in the Columbia River basalt, 12 were earthquakes in the pre-basalt sediments, and 17 were earthquakes in the crystalline basement. Geographically, 13 earthquakes occurred in swarm areas, 1 earthquake was associated with major structures, and 28 were random events. There were no earthquake triggers of the Hanford Strong Motion Accelerometers during fiscal year 2002.

  4. Second Quarter Hanford Seismic Report for Fiscal Year 2003

    SciTech Connect

    Hartshorn, Donald C.; Reidel, Steve P.; Rohay, Alan C.

    2003-04-16

    This describes the earthquakes that occurred on and near the Hanford Site during the second quarter of FY03. 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 271 triggers during the second quarter of fiscal year 2003. Of these triggers, 141 were earthquakes. Twenty earthquakes were located in the Hanford Seismic Network area. Stratigraphically 9 earthquakes occurred in the Columbia River basalt, 2 were earthquakes in the pre-basalt sediments, and 9 were earthquakes in the crystalline basement. Geographically, 6 earthquakes occurred in swarm areas, 2 earthquakes were associated with a major geologic structure, and 12 were classified as random events.

  5. 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

  6. Los Alamos Laser Eye Investigation.

    SciTech Connect

    Odom, C. R.

    2005-01-01

    A student working in a laser laboratory at Los Alamos National Laboratory sustained a serious retinal injury to her left eye when she attempted to view suspended particles in a partially evacuated target chamber. The principle investigator was using the white light from the flash lamp of a Class 4 Nd:YAG laser to illuminate the particles. Since the Q-switch was thought to be disabled at the time of the accident, the principal investigator assumed it would be safe to view the particles without wearing laser eye protection. The Laboratory Director appointed a team to investigate the accident and to report back to him the events and conditions leading up to the accident, equipment malfunctions, safety management causal factors, supervisory and management action/inaction, adequacy of institutional processes and procedures, emergency and notification response, effectiveness of corrective actions and lessons learned from previous similar events, and recommendations for human and institutional safety improvements. The team interviewed personnel, reviewed documents, and characterized systems and conditions in the laser laboratory during an intense six week investigation. The team determined that the direct and primary failures leading to this accident were, respectively, the principle investigator's unsafe work practices and the institution's inadequate monitoring of worker performance. This paper describes the details of the investigation, the human and institutional failures, and the recommendations for improving the laser safety program.

  7. Estimate of inner core rotation rate from United Kingdom regional seismic network data and consequences for inner core dynamical behaviour

    NASA Astrophysics Data System (ADS)

    Collier, Jonathan D.; Helffrich, George

    2001-12-01

    We analyse over 12 500 records of southwest Pacific earthquakes recorded by the UK network for PKP BC and PKP DF phases to seek constraints on the inner core's rotation rate. Careful analysis and strict rejection criteria yield 655 PKP BC-PKP DF differential travel time residuals computed with respect to the AK135 reference model, densely sampling a small region of the inner core over a time period of 15 years. The data images both lateral and radial velocity heterogeneity in the inner core located geographically beneath the north Pacific between radii of 870 and 1080 km. The dominant feature is a longitudinal wave speed gradient centred at about 180° longitude. In combination with different earthquake catalogues and inner core anisotropy models, we explore different techniques to use this gradient to constrain the rotation rate. Our estimates range from 0.45±0.25 to 0.74±0.29°/yr relative to the mantle, with two of four estimates including zero rotation at the 95% (2σ) confidence level, indicating that rotation is marginally detectable. As an alternative to monotonic rotation, we find weak evidence for rotational oscillation of the inner core on time scales of about 280 days. In consequence, these observations suggest that: (1) viscous coupling between the outer and inner core simulated using viscous hyperdiffusivity is not appropriate for modelling inner core rotation; (2) temperature gradients between the interior and exterior of the tangent cylinder in the core are also small; (3) gravitational torques coupling the inner core to the mantle are large, on the order of 2×10 21 Nm; and (4) the inner core's viscosity is high, 3.9×10 19 Pas.

  8. Updated Colombian Seismic Hazard Map

    NASA Astrophysics Data System (ADS)

    Eraso, J.; Arcila, M.; Romero, J.; Dimate, C.; Bermúdez, M. L.; Alvarado, C.

    2013-05-01

    The Colombian seismic hazard map used by the National Building Code (NSR-98) in effect until 2009 was developed in 1996. Since then, the National Seismological Network of Colombia has improved in both coverage and technology providing fifteen years of additional seismic records. These improvements have allowed a better understanding of the regional geology and tectonics which in addition to the seismic activity in Colombia with destructive effects has motivated the interest and the need to develop a new seismic hazard assessment in this country. Taking advantage of new instrumental information sources such as new broad band stations of the National Seismological Network, new historical seismicity data, standardized global databases availability, and in general, of advances in models and techniques, a new Colombian seismic hazard map was developed. A PSHA model was applied. The use of the PSHA model is because it incorporates the effects of all seismic sources that may affect a particular site solving the uncertainties caused by the parameters and assumptions defined in this kind of studies. First, the seismic sources geometry and a complete and homogeneous seismic catalog were defined; the parameters of seismic rate of each one of the seismic sources occurrence were calculated establishing a national seismotectonic model. Several of attenuation-distance relationships were selected depending on the type of seismicity considered. The seismic hazard was estimated using the CRISIS2007 software created by the Engineering Institute of the Universidad Nacional Autónoma de México -UNAM (National Autonomous University of Mexico). A uniformly spaced grid each 0.1° was used to calculate the peak ground acceleration (PGA) and response spectral values at 0.1, 0.2, 0.3, 0.5, 0.75, 1, 1.5, 2, 2.5 and 3.0 seconds with return periods of 75, 225, 475, 975 and 2475 years. For each site, a uniform hazard spectrum and exceedance rate curves were calculated. With the results, it is

  9. Hanford Seismic Report for Fiscal Year 2000

    SciTech Connect

    Hartshorn, D.C.; Reidel, S.; Rohay, A.C.

    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 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 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 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{degree}-47{degree}N latitude and 119{degree}-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

  10. A multiple receiver - multiple transmitter VLF high-order differential analysis evaluation network for near real-time detection and discrimination of seismic-ionospheric precursor phenomena

    NASA Astrophysics Data System (ADS)

    Skeberis, Christos; Zaharis, Zaharias; Xenos, Thomas; Spatalas, Spyridon; Stratakis, Dimitrios; Maggipinto, Tommaso; Biagi, Pier francesco

    2016-04-01

    This study provides an evaluation of the application of high-order differential analysis on VLF signals on a multiple-receiver multiple-transmitter network. This application provides a method for near-real-time detection of disturbances that can be attributed to seismic-ionospheric precursor phenomena and can discriminate disturbances that could be classified as false positives and thus should be attributed to other geomagnetic influences. VLF data acquired in Thessaloniki, Greece (40.59N, 22,78E) Herakleion, Greece (35.31N, 25.10E), Nicosia, Cyprus (35.17N, 33.35E), Italy (42.42N, 13.08E) and transmitted by the VLF station in Tavolara, Italy (ICV station 40.923N, 9.731E) and the station in Keflavik, Iceland (ICE 64.02N, 22.57W) from January 2015 to January 2016 were used for the purpose of this paper. The receivers have been developed by Elettronika Srl and are part of the International Network for Frontier Research on Earthquake Precursors (INFREP). The process applied for this study has been further developed and is based on differential analysis. The signals undergo transformation using an enhanced version of the Hilbert Huang Transform, and relevant spectra are produced. On the product of this process, differential analysis is applied. Finally, the method produces the correlation coefficient of signals that are on the same path over an earthquake epicenter in order to highlight disturbances, and on the opposite can make comparisons with unrelated transmitted signals of different paths to eliminate disturbances that are not localized to the area of interest. This improvement provides a simple method of noise cancellation to signals that would otherwise be considered as false positives. A further evaluation of the method is provided with the presentation and discussion of sample results. The method seems to be a robust tool of analysis of VLF signals and also an automatic detection tool with built-in noise cancellation of outside disturbances.

  11. The Puerto Rico Seismic Network Broadcast System: A user friendly GUI to broadcast earthquake messages, to generate shakemaps and to update catalogues

    NASA Astrophysics Data System (ADS)

    Velez, J.; Huerfano, V.; von Hillebrandt, C.

    2007-12-01

    The Puerto Rico Seismic Network (PRSN) has historically provided locations and magnitudes for earthquakes in the Puerto Rico and Virgin Islands (PRVI) region. PRSN is the reporting authority for the region bounded by latitudes 17.0N to 20.0N, and longitudes 63.5W to 69.0W. The main objective of the PRSN is to record, process, analyze, provide information and research local, regional and teleseismic earthquakes, providing high quality data and information to be able to respond to the needs of the emergency management, academic and research communities, and the general public. The PRSN runs Earthworm software (Johnson et al, 1995) to acquire and write waveforms to disk for permanent archival. Automatic locations and alerts are generated for events in Puerto Rico, the Intra America Seas, and the Atlantic by the EarlyBird system (Whitmore and Sokolowski, 2002), which monitors PRSN stations as well as some 40 additional stations run by networks operating in North, Central and South America and other sites in the Caribbean. PRDANIS (Puerto Rico Data Analysis and Information System) software, developed by PRSN, supports manual locations and analyst review of automatic locations of events within the PRSN area of responsibility (AOR), using all the broadband, strong-motion and short-period waveforms Rapidly available information regarding the geographic distribution of ground shaking in relation to the population and infrastructure at risk can assist emergency response communities in efficient and optimized allocation of resources following a large earthquake. The ShakeMap system developed by the USGS provides near real-time maps of instrumental ground motions and shaking intensity and has proven effective in rapid assessment of the extent of shaking and potential damage after significant earthquakes (Wald, 2004). In Northern and Southern California, the Pacific Northwest, and the states of Utah and Nevada, ShakeMaps are used for emergency planning and response, loss

  12. Products and Services Available from the Southern California Earthquake Data Center (SCEDC) and the Southern California Seismic Network (SCSN)

    NASA Astrophysics Data System (ADS)

    Chen, S. E.; Yu, E.; Bhaskaran, A.; Chowdhury, F. R.; Meisenhelter, S.; Hutton, K.; Given, D.; Hauksson, E.; Clayton, R. W.

    2011-12-01

    Currently, the SCEDC archives continuous and triggered data from nearly 8400 data channels from 425 SCSN recorded stations, processing and archiving an average of 6.4 TB of continuous waveforms and 12,000 earthquakes each year. The SCEDC provides public access to these earthquake parametric and waveform data through its website www.data.scec.org and through client applications such as STP and DHI. This poster will describe the most significant developments at the SCEDC during 2011. New website design: ? The SCEDC has revamped its website. The changes make it easier for users to search the archive, discover updates and new content. These changes also improve our ability to manage and update the site. New data holdings: ? Post processing on El Mayor Cucapah 7.2 sequence continues. To date there have been 11847 events reviewed. Updates are available in the earthquake catalog immediately. ? A double difference catalog (Hauksson et. al 2011) spanning 1981 to 6/30/11 will be available for download at www.data.scec.org and available via STP. ? A focal mechanism catalog determined by Yang et al. 2011 is available for distribution at www.data.scec.org. ? Waveforms from Southern California NetQuake stations are now being stored in the SCEDC archive and available via STP as event associated waveforms. Amplitudes from these stations are also being stored in the archive and used by ShakeMap. ? As part of a NASA/AIST project in collaboration with JPL and SIO, the SCEDC will receive real time 1 sps streams of GPS displacement solutions from the California Real Time Network (http://sopac.ucsd.edu/projects/realtime; Genrich and Bock, 2006, J. Geophys. Res.). These channels will be archived at the SCEDC as miniSEED waveforms, which then can be distributed to the user community via applications such as STP. Improvements in the user tool STP: ? STP sac output now includes picks from the SCSN. New archival methods: ? The SCEDC is exploring the feasibility of archiving and distributing

  13. Newberry EGS Seismic Velocity Model

    DOE Data Explorer

    Templeton, Dennise

    2013-10-01

    We use ambient noise correlation (ANC) to create a detailed image of the subsurface seismic velocity at the Newberry EGS site down to 5 km. We collected continuous data for the 22 stations in the Newberry network, together with 12 additional stations from the nearby CC, UO and UW networks. The data were instrument corrected, whitened and converted to single bit traces before cross correlation according to the methodology in Benson (2007). There are 231 unique paths connecting the 22 stations of the Newberry network. The additional networks extended that to 402 unique paths crossing beneath the Newberry site.

  14. Canadian seismic agreement

    SciTech Connect

    Wetmiller, R.J.; Lyons, J.A.; Shannon, W.E.; Munro, P.S.; Thomas, J.T.; Andrew, M.D.; Lamontagne, M.; Wong, C., Anglin, F.M.; Plouffe, M.; Lapointe, S.P.; Adams, J.; Drysdale, J.A. . Geophysics Div.)

    1990-04-01

    This is the twenty-first progress report under the agreement entitled Canadian Seismic Agreement between the US Nuclear Regulatory Commission (NRC) and the Canadian Commercial Corporation. Activities undertaken by the Geophysics Division of the Geological Survey of Canada (GD/GSC) during the period from July 01, 1988 to June 30, 1989 and supported in part by the NRC agreement are described below under four headings; Eastern Canada Telemetred Network and local network developments, Datalab developments, strong motion network developments and earthquake activity. In this time period eastern Canada experienced its largest earthquake in over 50 years. This earthquake, which has been christened the Saguenay earthquake, has provided a wealth of new data pertinent to earthquake engineering studies in eastern North America and is the subject of many continuing studies, which are presently being carried out at GD and elsewhere. 41 refs., 21 figs., 7 tabs.

  15. 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)

  16. 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. 

  17. 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

  18. Imaging geothermal systems associated with oceanic ridge: first analysis of records from a dense seismic network deployed within and around the Reykjanes high-temperature area, SW-Iceland

    NASA Astrophysics Data System (ADS)

    Jousset, P. G.; Ágústsson, K.; Verdel, A.; Blanck, H.; Stefánsson, S. A.; Erbas, K.; Deon, F.; Erlendsson, Ö.; Guðnason, E. Á.; Specht, S.; Hersir, G. P.; Halldórsdóttir, S.; Wemstraa, K.; Franke, S.; Bruhn, D.; Flovenz, O. G.; Tryggvason, H.; Friðleifsson, G. Ó.

    2014-12-01

    Manifestations of supercritical water in magmatic environments have so far only been accessible from analogue outcrops of fossil systems and by simulating pressure/temperature conditions in the laboratory. In order to assess the unknown properties of such reservoirs, scientific drilling is used when Earth surface sampled rocks cannot sufficiently explain past geological processes and when geophysical imaging does not sufficiently explain observed phenomena. However, our understanding of structural and dynamic characteristics of geothermal systems can be improved through application of advanced and/or innovative exploration technologies. Unlike resistivity imaging, active and passive seismic techniques have rarely been used in volcanic geothermal areas, because processing techniques were not adapted to geothermal conditions. Recent advances in volcano-seismology have introduced new processing techniques for assessing subsurface structures and controls on fluid flow in geothermal systems. We present here preliminary analyses of seismic records around a geothermal reservoir located both on-land and offshore along the Reykjanes Ridge, SW-Iceland. We deployed on-land stations (20 broad-band and 10 short-period seismometers) and 24 Ocean Bottom Seismometers which are recording since April 2014. Together with existing permanent stations, the complete network comprises 66 stations. The network was designed so that several processing techniques can be used with the data set and address scientific questions concerning geothermal systems and the oceanic ridge. We present the network deployment, our approach and preliminary results from the first months.

  19. Does seismic activity control carbon exchanges between transform-faults in old ocean crust and the deep sea? A hypothesis examined by the EU COST network FLOWS

    NASA Astrophysics Data System (ADS)

    Lever, M. A.

    2014-12-01

    The European Cooperation in Science and Technology (COST)-Action FLOWS (http://www.cost.eu/domains_actions/essem/Actions/ES1301) was initiated on the 25th of October 2013. It is a consortium formed by members of currently 14 COST countries and external partners striving to better understand the interplay between earthquakes and fluid flow at transform-faults in old oceanic crust. The recent occurrence of large earthquakes and discovery of deep fluid seepage calls for a revision of the postulated hydrogeological inactivity and low seismic activity of old oceanic transform-type plate boundaries, and indicates that earthquakes and fluid flow are intrinsically associated. This Action merges the expertise of a large number of research groups and supports the development of multidisciplinary knowledge on how seep fluid (bio)chemistry relates to seismicity. It aims to identify (bio)geochemical proxies for the detection of precursory seismic signals and to develop innovative physico-chemical sensors for deep-ocean seismogenic faults. National efforts are coordinated through Working Groups (WGs) focused on 1) geophysical and (bio)geochemical data acquisition; 2) modelling of structure and seismicity of faults; 3) engineering of deep-ocean physico-chemical seismic sensors; and 4) integration and dissemination. This poster will illustrate the overarching goals of the FLOWS Group, with special focus to research goals concerning the role of seismic activity in controlling the release of carbon from the old ocean crust into the deep ocean.

  20. Seismic calm predictors of rockburst

    NASA Astrophysics Data System (ADS)

    Zmushko, Tatjana; Turuntaev, Sergey; Kulikov, Vladimir

    2013-04-01

    The method of "seismic calm" is widely used for forecasting of strong natural earthquakes (Sobolev G.A., Ponomarev A.V., 2003). The "seismic calm" means that during some time period before the main earthquake, the smaller events (with energies of several order smaller than that of the main earthquake) don't occur. In the presented paper the applicability of the method based on the idea of seismic calm for forecasting rockburst is considered. Three deposits (with seismicity induced by mining) are analyzed: Tashtagol iron deposit (Altai, Russia), Vorkuta (North Ural, Russia) and Barentsburg (Spitsbergen, Norway) coalmines. Local seismic monitoring networks are installed on each of them. The catalogues of seismic events were processed and strong events (rockbursts) were studied (Vorkuta M=2,3; Barentsburg M=1,8; Tashtagol M=1,9÷2,2). All catalogues cover at least two years (Vorkuta - 2008-2011, Barentsburg - 2011-2012, Tashtagol - 2002-2012). It was found that the number of seismic events with magnitudes M=0,5÷1 decreased in a month before the main strong event at Vorkuta coalmines. This event was not directly related with coal mining, its epicenter was located aside of the area of coal mining. In Barentsburg mine the rockburst wasn't so strong as in Vorkuta. The number of events with energies M=0,5 decreased slightly before the rockburst, but not so obviously as in Vorkuta case. The seismic events with high energies occur often at Tashtagol iron deposit. Mining methods used there differ from the coal deposit mining. At coalmines the mining combine runs from edge to edge of the wall, cutting off the coal. The considered iron deposit is developed by a method of block blasting. Not all rockbursts occur immediately after the blasting, so, the problem of the rockburst prediction is important for mining safety. To find rockburst precursors it is necessary to separate the events occurred due to the block blasting from the seismic events due to relocation of stresses in

  1. Quantifying the seismicity on Taiwan

    NASA Astrophysics Data System (ADS)

    Wu, Yi-Hsuan; Chen, Chien-Chih; Turcotte, Donald L.; Rundle, John B.

    2013-07-01

    We quantify the seismicity on the island of Taiwan using the frequency-magnitude statistics of earthquakes since 1900. A break in Gutenberg-Richter scaling for large earthquakes in global seismicity has been observed, this break is also observed in our Taiwan study. The seismic data from the Central Weather Bureau Seismic Network are in good agreement with the Gutenberg-Richter relation taking b ≈ 1 when M < 7. For large earthquakes, M ≥ 7, the seismic data fit Gutenberg-Richter scaling with b ≈ 1.5. If the Gutenberg-Richter scaling for M < 7 earthquakes is extrapolated to larger earthquakes, we would expect a M > 8 earthquake in the study region about every 25 yr. However, our analysis shows a lower frequency of occurrence of large earthquakes so that the expected frequency of M > 8 earthquakes is about 200 yr. The level of seismicity for smaller earthquakes on Taiwan is about 12 times greater than in Southern California and the possibility of a M ≈ 9 earthquake north or south of Taiwan cannot be ruled out. In light of the Fukushima, Japan nuclear disaster, we also discuss the implications of our study for the three operating nuclear power plants on the coast of Taiwan.

  2. Synchronous changes in the seismicity rate and ocean-bottom hydrostatic pressures along the Nankai trough: A possible slow slip event detected by the Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET)

    NASA Astrophysics Data System (ADS)

    Suzuki, Kensuke; Nakano, Masaru; Takahashi, Narumi; Hori, Takane; Kamiya, Shinichiro; Araki, Eiichiro; Nakata, Ryoko; Kaneda, Yoshiyuki

    2016-06-01

    We detected long-term hydrostatic pressure changes at ocean-bottom stations of the Dense Oceanfloor Network system for Earthquakes and Tsunamis (DONET) along the Nankai trough, off southwestern Japan. We detected these changes after removing the contributions of ocean mass variations and sensor drift from the records. In addition, we detected a decrease in the background seismicity rate of a nearby earthquake cluster that was synchronous with the hydrostatic pressure changes. We interpreted these observed hydrostatic pressure changes to reflect vertical deformation of the ocean floor of 3-8 cm, and we consider the cause of the seafloor crustal deformation to be a slow slip event (SSE) beneath the stations. Because the pressure changes were observed at stations with distances less than 20 km to each other, we inferred that the SSE occurred in the shallow part of the sedimentary wedge, such as on a splay fault system. The synchronous observation of an SSE and a seismicity rate change suggests that both were triggered by a change in the regional stress that may be associated with stress accumulation and release processes occurring along the Nankai trough. These data show that continuous and careful monitoring of crustal activities by DONET stations provides an effective way to detect seismic and geodetic signals related to the occurrence of megathrust or other types of large earthquakes.

  3. Computational 3-D inversion for seismic exploration

    SciTech Connect

    Gavrilov, E.M.; Forslund, D.W.; Fehler, M.C.

    1997-10-01

    This is the final report of a four-month, Laboratory Directed Research and Development (LDRD) project carried out at the Los Alamos National Laboratory (LANL). There is a great need for a new and effective technology with a wide scope of industrial applications to investigate media internal properties of which can be explored only from the backscattered data. The project was dedicated to the development of a three-dimensional computational inversion tool for seismic exploration. The new computational concept of the inversion algorithm was suggested. The goal of the project was to prove the concept and the practical validity of the algorithm for petroleum exploration.

  4. 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

  5. New Generation of Los Alamos Opacity Tables

    NASA Astrophysics Data System (ADS)

    Colgan, James; Kilcrease, D. P.; Magee, N. H.; Sherrill, M. E.; Abdallah, J.; Hakel, P.; Fontes, C. J.; Guzik, J. A.; Mussack, K. A.

    2016-05-01

    We present a new generation of Los Alamos OPLIB opacity tables that have been computed using the ATOMIC code. Our tables have been calculated for all 30 elements from hydrogen through zinc and are publicly available through our website. In this poster we discuss the details of the calculations that underpin the new opacity tables. We also show several recent applications of the use of our opacity tables to solar modeling and other astrophysical applications. In particular, we demonstrate that use of the new opacities improves the agreement between solar models and helioseismology, but does not fully resolve the long-standing `solar abundance' problem. The Los Alamos National Laboratory is operated by Los Alamos National Security, LLC for the National Nuclear Security Administration of the U.S. Department of Energy under Contract No. DE-AC5206NA25396.

  6. Status of Monte Carlo at Los Alamos

    SciTech Connect

    Thompson, W.L.; Cashwell, E.D.

    1980-01-01

    At Los Alamos the early work of Fermi, von Neumann, and Ulam has been developed and supplemented by many followers, notably Cashwell and Everett, and the main product today is the continuous-energy, general-purpose, generalized-geometry, time-dependent, coupled neutron-photon transport code called MCNP. The Los Alamos Monte Carlo research and development effort is concentrated in Group X-6. MCNP treats an arbitrary three-dimensional configuration of arbitrary materials in geometric cells bounded by first- and second-degree surfaces and some fourth-degree surfaces (elliptical tori). Monte Carlo has evolved into perhaps the main method for radiation transport calculations at Los Alamos. MCNP is used in every technical division at the Laboratory by over 130 users about 600 times a month accounting for nearly 200 hours of CDC-7600 time.

  7. Publications of Los Alamos Research, 1983

    SciTech Connect

    Sheridan, C.J.; McClary, W.J.; Rich, J.A.; Rodriguez, L.L.

    1984-10-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1983. Papers published in 1982 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted - even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was published more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-Laboratory reports, journal articles, books, chapters of books, conference papers either published separately or as part of conference proceedings issued as books or reports, papers publishd in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  8. Publications of Los Alamos research 1980

    SciTech Connect

    Salazar, C.A.; Willis, J.K.

    1981-09-01

    This bibliography is a compilation of unclassified publications of work done at the Los Alamos National Laboratory for 1980. Papers published in 1980 are included regardless of when they were actually written. Publications received too late for inclusion in earlier compilations have also been listed. Declassification of previously classified reports is considered to constitute publication. All classified issuances are omitted-even those papers, themselves unclassified, which were published only as part of a classified document. If a paper was pubished more than once, all places of publication are included. The bibliography includes Los Alamos National Laboratory reports, papers released as non-laboratory reports, journal articles, books, chapters of books, conference papers published either separately or as part of conference proceedings issued as books or reports, papers published in congressional hearings, theses, and US patents. Publications by Los Alamos authors that are not records of Laboratory-sponsored work are included when the Library becomes aware of them.

  9. Los Alamos Center for Computer Security formal computer security model

    SciTech Connect

    Dreicer, J.S.; Hunteman, W.J.; Markin, J.T.

    1989-01-01

    This paper provides a brief presentation of the formal computer security model currently being developed at the Los Alamos Department of Energy (DOE) Center for Computer Security (CCS). The need to test and verify DOE computer security policy implementation first motivated this effort. The actual analytical model was a result of the integration of current research in computer security and previous modeling and research experiences. The model is being developed to define a generic view of the computer and network security domains, to provide a theoretical basis for the design of a security model, and to address the limitations of present formal mathematical models for computer security. The fundamental objective of computer security is to prevent the unauthorized and unaccountable access to a system. The inherent vulnerabilities of computer systems result in various threats from unauthorized access. The foundation of the Los Alamos DOE CCS model is a series of functionally dependent probability equations, relations, and expressions. The model is undergoing continued discrimination and evolution. We expect to apply the model to the discipline of the Bell and LaPadula abstract sets of objects and subjects. 6 refs.

  10. SEDs at Los Alamos: A Personal Memoir

    NASA Astrophysics Data System (ADS)

    Bederson, Benjamin

    2001-03-01

    I have written this personal memoir approximately 55 years after the events I describe. It is based almost exclusively on memory, since apart from the diary I kept while on Tinian, I have few documents concerning it. It covers my service in the U.S. Army's Special Engineering Detachment (SED) in Oak Ridge and Los Alamos in 1944-45, on Tinian island, the launching pad for the bombing raids on Japan, in the summer and fall of 1945, and my return to Los Alamos until my discharge in January 1946.

  11. Upper Los Alamos canyon fact sheet

    SciTech Connect

    Berger, Jeffrey H

    2007-01-01

    Los Alamos National Laboratory is planning to make environmental assessments in portions of Upper Los Alamos Canyon. Upper Los Alamos Canyon is one of the areas included in the 2005 Consent Order agreed to by Los Alamos National Laboratory, the National Nuclear Security Administration, and the New Mexico Environment Department. As such, it must be evaluated for potential contamination. The area is located within and south of the Los Alamos townsite in Technical Areas 00, 01, 03, 32, 41, 43, and 61 of Los Alamos National Laboratory and includes a total of 115 solid waste management units and areas of concern. This area was home to some of the earliest operations at Los Alamos, dating from the 1940s. Of the 115 solid-waste management units and areas of concern, 54 have been addressed previously. The remaining 61 are the focus of this project. These include septic tanks and outfalls, sanitary and industrial waste lines, storm drains, soil contamination areas, landfill and surface disposal areas, transformer sites, and incinerators. The Consent Order requires the Laboratory to evaluate historical work sites for the potential presence of residual contamination. It also requires the Laboratory to identify and implement corrective actions should contamination be found. The Laboratory began performing these types of activities in the 1990s. The Upper Los Alamos Canyon project entails: (1) collecting soil and rock samples using the most efficient and least-invasive methods practicable; (2) defining the nature and extent of any residual contamination associated with each solid waste management unit or area of concern; and (3) gathering additional data if needed to evaluate potential remedial alternatives. A variety of methods, including studies of engineering drawings, nonintrusive geophysical surveys, and trenching, may be used to identify the final sampling locations. The field team then determines which collection method to use at each location, based on such site

  12. Plutonium 238 facilities at Los Alamos

    NASA Astrophysics Data System (ADS)

    Rinehart, Gary H.

    1991-01-01

    Plutonium 238 operations at Los Alamos are performed at the Plutonium Facility (TA-55), the Chemistry and Metallurgy Research (CMR) Building, and the Radioisotope Fuels Impact Test Facility. The plutonium 238 facilities at Los Alamos support a wide variety of heat source activities including development of new fuel forms and containment materials, research on the high temperature properties of containment materials, investigation of the high temperature compatibility of fuels with potential container materials, processing plutonium 238 fuel forms, manufacture of heat sources under quality assurance surveillance, and performing safety testing on heat sources and radioisotope thermoelectric generators.

  13. Plutonium-238 facilities at Los Alamos

    NASA Astrophysics Data System (ADS)

    Rinehart, Gary H.

    Plutonium-238 operations at Los Alamos are performed at the Plutonium Facility (TA-55), the Chemistry and Metallurgy Research (CMR) Building, and the Radioisotope Fuels Impact Test Facility. The plutonium-238 facilities at Los Alamos support a wide variety of heat source activities including development of new fuel forms and containment materials, research on the high temperature properties of containment materials, investigation of the high temperature compatibility of fuels with potential container materials, processing plutonium-238 fuel forms, manufacture of heat sources under quality assurance surveillance, and performing safety testing on heat sources and radioisotope thermoelectric generators.

  14. Simultaneous Estimation of Earthquake Source Parameters and Site Response from Inversion of Strong Motion Network Data in Kachchh Seismic Zone, Gujarat, India

    NASA Astrophysics Data System (ADS)

    Dutta, U.; Mandal, P.

    2010-12-01

    Inversion of horizontal components of S-wave spectral data in the frequency range 0.1-10.0 Hz has been carried out to estimate simultaneously the source spectra of 38 aftershocks (Mw 2.93-5.32) of the 2001 Bhuj earthquake (Mw 7.7) and site response at 18 strong motion sites in the Kachchh Seismic Zone, Gujarat, India. The spatial variation of site response (SR) in the region has been studied by averaging the SR values obtained from the inversion in two frequency bands; 0.2-1.8 Hz and 3.0-7.0 Hz, respectively. In 0.2-1.8 Hz frequency band, the high SR values are observed in the southern part of the Kachchh Mainland Fault that had suffered extensively during the 2001 Bhuj Earthquake. However, for 3.0-7.0 Hz band, the area of Jurassic and Quaternary Formations show predominantly high SR. The source spectral data obtained from the inversion were used to estimate various source parameters namely, the seismic moment, stress drop, corner frequency and radius of source rupture by using an iterative least squares inversion approach based on the Marquardt-Levenberg algorithm. It has been observed that the seismic moment and radius of rupture from 38 aftershocks vary between 3.1x10^{13} to 2.0x10^{17} Nm and 226 to 889 m, respectively. The stress drop values from these aftershocks are found to vary from 0.11 to 7.44 MPa. A significant scatter of stress drop values has been noticed in case of larger aftershocks while for smaller magnitude events, it varies proportionally with the seismic moment. The regression analysis between seismic moment and radius of rupture indicates a break in linear scaling around 10^{15.3} Nm. The seismic moment of these aftershocks found to be proportional to the corner frequency, which is consistent for earthquakes with such short rupture length.

  15. 50 years of Global Seismic Observations

    NASA Astrophysics Data System (ADS)

    Anderson, K. R.; Butler, R.; Berger, J.; Davis, P.; Derr, J.; Gee, L.; Hutt, C. R.; Leith, W. S.; Park, J. J.

    2007-12-01

    Seismological recordings have been made on Earth for hundreds of years in some form or another, however, global monitoring of earthquakes only began in the 1890's when John Milne created 40 seismic observatories to measure the waves from these events. Shortly after the International Geophysical Year (IGY), a concerted effort was made to establish and maintain a more modern standardized seismic network on the global scale. In the early 1960's, the World-Wide Standardized Seismograph Network (WWSSN) was established through funding from the Advanced Research Projects Agency (ARPA) and was installed and maintained by the USGS's Albuquerque Seismological Laboratory (then a part of the US Coast and Geodetic Survey). This network of identical seismic instruments consisted of 120 stations in 60 countries. Although the network was motivated by nuclear test monitoring, the WWSSN facilitated numerous advances in observational seismology. From the IGY to the present, the network has been upgraded (High-Gain Long-Period Seismograph Network, Seismic Research Observatories, Digital WWSSN, Global Telemetered Seismograph Network, etc.) and expanded (International Deployment of Accelerometers, US National Seismic Network, China Digital Seismograph Network, Joint Seismic Project, etc.), bringing the modern day Global Seismographic Network (GSN) to a current state of approximately 150 stations. The GSN consists of state-of-the-art very broadband seismic transducers, continuous power and communications, and ancillary sensors including geodetic, geomagnetic, microbarographic, meteorological and other related instrumentation. Beyond the GSN, the system of global network observatories includes contributions from other international partners (e.g., GEOSCOPE, GEOFON, MEDNET, F-Net, CTBTO), forming an even larger backbone of permanent seismological observatories as a part of the International Federation of Digital Seismograph Networks. 50 years of seismic network operations have provided

  16. Seismic event classification system

    DOEpatents

    Dowla, F.U.; Jarpe, S.P.; Maurer, W.

    1994-12-13

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. Self-organizing neural networks (SONNs) can be used for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs are useful for this purpose. Given the detection of a seismic event and the corresponding signal, computation is made of: the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This pre-processed input is fed into the SONNs. These neural networks are able to group events that look similar. The ART SONN has an advantage in classifying the event because the types of cluster groups do not need to be pre-defined. The results from the SONNs together with an expert seismologist's classification are then used to derive event classification probabilities. 21 figures.

  17. Seismic event classification system

    DOEpatents

    Dowla, Farid U.; Jarpe, Stephen P.; Maurer, William

    1994-01-01

    In the computer interpretation of seismic data, the critical first step is to identify the general class of an unknown event. For example, the classification might be: teleseismic, regional, local, vehicular, or noise. Self-organizing neural networks (SONNs) can be used for classifying such events. Both Kohonen and Adaptive Resonance Theory (ART) SONNs are useful for this purpose. Given the detection of a seismic event and the corresponding signal, computation is made of: the time-frequency distribution, its binary representation, and finally a shift-invariant representation, which is the magnitude of the two-dimensional Fourier transform (2-D FFT) of the binary time-frequency distribution. This pre-processed input is fed into the SONNs. These neural networks are able to group events that look similar. The ART SONN has an advantage in classifying the event because the types of cluster groups do not need to be pre-defined. The results from the SONNs together with an expert seismologist's classification are then used to derive event classification probabilities.

  18. The Apollo passive seismic experiment

    NASA Technical Reports Server (NTRS)

    Latham, G. V.; Dorman, H. J.; Horvath, P.; Ibrahim, A. K.; Koyama, J.; Nakamura, Y.

    1979-01-01

    The completed data set obtained from the 4-station Apollo seismic network includes signals from approximately 11,800 events of various types. Four data sets for use by other investigators, through the NSSDC, are in preparation. Some refinement of the lunar model based on seismic data can be expected, but its gross features remain as presented two years ago. The existence of a small, molten core remains dependent upon the analysis of signals from a single, far-side impact. Analysis of secondary arrivals from other sources may eventually resolve this issue, as well as continued refinement of the magnetic field measurements. Evidence of considerable lateral heterogeneity within the moon continues to build. The mystery of the much meteoroid flux estimate derived from lunar seismic measurements, as compared with earth-based estimates, remains; although, significant correlations between terrestrial and lunar observations are beginning to emerge.

  19. Proceedings of the Los Alamos neutrino workshop

    SciTech Connect

    Boehm, F.; Stephenson, G.J. Jr.

    1982-08-01

    A workshop on neutrino physics was held at Los Alamos from June 8 to 12, 1981. The material presented has been provided in part by the organizers, in part by the chairmen of the working sessions. Closing date for contributions was October 1981.

  20. Induction inserts at the Los Alamos PSR

    SciTech Connect

    King-Yuen Ng

    2002-09-30

    Ferrite-loaded induction tuners installed in the Los Alamos Proton Storage Ring have been successful in compensating space-charge effects. However, the resistive part of the ferrite introduces unacceptable microwave instability and severe bunch lengthening. An effective cure was found by heating the ferrite cores up to {approx} 130 C. An understanding of the instability and cure is presented.

  1. Los Alamos waste drum shufflers users manual

    SciTech Connect

    Rinard, P.M.; Adams, E.L.; Painter, J.

    1993-08-24

    This user manual describes the Los Alamos waste drum shufflers. The primary purpose of the instruments is to assay the mass of {sup 235}U (or other fissile materials) in drums of assorted waste. It can perform passive assays for isotopes that spontaneously emit neutrons or active assays using the shuffler technique as described on this manual.

  2. Seafloor spreading event in western Gulf of Aden during the November 2010 - March 2011 period captured by regional seismic networks: Evidence for diking events and interactions with a nascent transform zone

    NASA Astrophysics Data System (ADS)

    Abdulhakim, Ahmed; Cécile, Doubre; Sylvie, Leroy; Kassim, Mohamed; Derek, Keir; Abayazid, Ahmadine; Julie, Perrot; Laurence, Audin; Jérome, Vergne; Alexandre, Nercessian; Eric, Jacques; Khaled, Khanbari; Jamal, Sholan; Frédérique, Rolandone; Ismael, Alganad

    2016-02-01

    In November 2010, intense seismic activity including 29 events with a magnitude above 5.0, started in the western part of the Gulf of Aden, where the structure of the oceanic spreading ridge is characterized by a series of N115°-trending slow-spreading segments set within an EW-trending rift. Using signals recorded by permanent and temporary networks in Djibouti and Yemen, we located 1122 earthquakes, with a magnitude ranging from 2.1 to 5.6 from 01 November 2010 to 31 March 2011. By looking in detail at the space-time distribution of the overall seismicity, and both the frequency and the moment tensor of large earthquakes, we reexamine the chronology of this episode. In addition we also interpret the origin of the activity using high-resolution bathymetric data, as well as from observations of sea-floor cable damage caused by high temperatures and lava flows. The analysis allows us to identify distinct active areas. Firstly, we interpret that this episode is mainly related to a diking event along a specific ridge segment, located at E044°. In light of previous diking episodes in nearby subaerial rift segments, for which field constraints and both seismic and geodetic data exist, we interpret the space-time evolution of the seismicity of the first few days. Migration of earthquakes suggests initial magma ascent below the segment center. This is followed by a southeastward dike propagation below the rift immediately followed by a northwestward dike propagation below the rift ending below the northern ridge wall. The cumulative seismic moment associated with this sequence reaches 9.1 × 1017 Nm, and taking into account a very low seismic versus geodetic moment, we estimate an horizontal opening of ˜0.58 to 2.9 m. The seismic activity that followed occurred through several bursts of earthquakes aligned along the segment axis, which are interpreted as short dike intrusions implying fast replenishment of the crustal magma reservoir feeding the dikes. Over the whole

  3. Seafloor spreading event in western Gulf of Aden during the November 2010-March 2011 period captured by regional seismic networks: evidence for diking events and interactions with a nascent transform zone

    NASA Astrophysics Data System (ADS)

    Ahmed, Abdulhakim; Doubre, Cécile; Leroy, Sylvie; Kassim, Mohamed; Keir, Derek; Abayazid, Ahmadine; Julie, Perrot; Laurence, Audin; Vergne, Jérome; Alexandre, Nercessian; Jacques, Eric; Khanbari, Khaled; Sholan, Jamal; Rolandone, Frédérique; Al-Ganad, Ismael

    2016-05-01

    In November 2010, intense seismic activity including 29 events with a magnitude above 5.0, started in the western part of the Gulf of Aden, where the structure of the oceanic spreading ridge is characterized by a series of N115°-trending slow-spreading segments set within an EW-trending rift. Using signals recorded by permanent and temporary networks in Djibouti and Yemen, we located 1122 earthquakes, with a magnitude ranging from 2.1 to 5.6 from 2010 November 1 to 2011 March 31. By looking in detail at the space-time distribution of the overall seismicity, and both the frequency and the moment tensor of large earthquakes, we re-examine the chronology of this episode. In addition, we also interpret the origin of the activity using high-resolution bathymetric data, as well as from observations of seafloor cable damage caused by high temperatures and lava flows. The analysis allows us to identify distinct active areas. First, we interpret that this episode is mainly related to a diking event along a specific ridge segment, located at E044°. In light of previous diking episodes in nearby subaerial rift segments, for which field constraints and both seismic and geodetic data exist, we interpret the space-time evolution of the seismicity of the first few days. Migration of earthquakes suggests initial magma ascent below the segment centre. This is followed by a southeastward dike propagation below the rift immediately followed by a northwestward dike propagation below the rift ending below the northern ridge wall. The cumulative seismic moment associated with this sequence reaches 9.1 × 1017 Nm, and taking into account a very low seismic versus geodetic moment, we estimate a horizontal opening of ˜0.58-2.9 m. The seismic activity that followed occurred through several bursts of earthquakes aligned along the segment axis, which are interpreted as short dike intrusions implying fast replenishment of the crustal magma reservoir feeding the dikes. Over the whole period

  4. Los Alamos Fires From Landsat 7

    NASA Technical Reports Server (NTRS)

    2002-01-01

    On May 9, 2000, the Landsat 7 satellite acquired an image of the area around Los Alamos, New Mexico. The Landsat 7 satellite acquired this image from 427 miles in space through its sensor called the Enhanced Thematic Mapper Plus (ETM+). Evident within the imagery is a view of the ongoing Cerro Grande fire near the town of Los Alamos and the Los Alamos National Laboratory. Combining the high-resolution (30 meters per pixel in this scene) imaging capacity of ETM+ with its multi-spectral capabilities allows scientists to penetrate the smoke plume and see the structure of the fire on the surface. Notice the high-level of detail in the infrared image (bottom), in which burn scars are clearly distinguished from the hotter smoldering and flaming parts of the fire. Within this image pair several features are clearly visible, including the Cerro Grande fire and smoke plume, the town of Los Alamos, the Los Alamos National Laboratory and associated property, and Cerro Grande peak. Combining ETM+ channels 7, 4, and 2 (one visible and two infrared channels) results in a false color image where vegetation appears as bright to dark green (bottom image). Forested areas are generally dark green while herbaceous vegetation is light green. Rangeland or more open areas appear pink to light purple. Areas with extensive pavement or urban development appear light blue or white to purple. Less densely-developed residential areas appear light green and golf courses are very bright green. The areas recently burned appear black. Dark red to bright red patches, or linear features within the burned area, are the hottest and possibly actively burning areas of the fire. The fire is spreading downslope and the front of the fire is readily detectable about 2 kilometers to the west and south of Los Alamos. Combining ETM+ channels 3, 2, and 1 provides a true-color image of the greater Los Alamos region (top image). Vegetation is generally dark to medium green. Forested areas are very dark green

  5. Los Alamos National Laboratory support to IAEA environmental safeguards

    SciTech Connect

    Steiner, Robert E; Dry, Don E; Roensch, Fred R; Kinman, Will S; Roach, Jeff L; La Mont, Stephen P

    2010-12-01

    The nuclear and radiochemistry group provides sample preparation and analysis support to the International Atomic Energy Agency (IAEA) Network of Analytical Laboratories (NWAL). These analyses include both non-destructive (alpha and gamma-ray spectrometry) and destructive (thermal ionization mass spectrometry and inductively coupled plasma mass spectrometry) methods. On a bi-annual basis the NWAL laboratories are invited to meet to discuss program evolution and issues. During this meeting each participating laboratory summarizes their efforts over the previous two years. This presentation will present Los Alamos National Laboratories efforts in support of this program. Data showing results from sample and blank analysis will be presented along with capability enhancement and issues that arose over the previous two years.

  6. Misuse and intrusion detection at Los Alamos National Laboratory

    SciTech Connect

    Jackson, K.A.; Neuman, M.C.; Simmonds, D.D.; Stallings, C.A.; Thompson, J.L.; Christoph, G.G.

    1995-04-01

    An effective method for detecting computer misuse is the automatic auditing and analysis of on-line user activity. This activity is reflected in system audit records, in system vulnerability postures, and in other evidence found through active system testing. Since 1989 we have implemented a misuse and intrusion detection system at Los Alamos. This is the Network Anomaly Detection and Intrusion Reporter, or NADIR. NADIR currently audits a Kerberos distributed authentication system, file activity on a mass, storage system, and four Cray supercomputers that run the UNICOS operating system. NADIR summarizes user activity and system configuration in statistical profiles. It compares these profiles to expert rules that define security policy and improper or suspicious behavior. It reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations, As NADIR is constantly evolving, this paper reports its development to date.

  7. 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.

  8. 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

  9. Networks.

    ERIC Educational Resources Information Center

    Maughan, George R.; Petitto, Karen R.; McLaughlin, Don

    2001-01-01

    Describes the connectivity features and options of modern campus communication and information system networks, including signal transmission (wire-based and wireless), signal switching, convergence of networks, and network assessment variables, to enable campus leaders to make sound future-oriented decisions. (EV)

  10. Environmental assessment for the proposed CMR Building upgrades at the Los Alamos National Laboratory, Los Alamos, New Mexico. Final document

    SciTech Connect

    1997-02-04

    In order to maintain its ability to continue to conduct uninterrupted radioactive and metallurgical research in a safe, secure, and environmentally sound manner, the US Department of Energy (DOE) proposes to upgrade the Los Alamos National Laboratory (LANL) Chemistry and Metallurgy Research (CMR) Building. The building was built in the early 1950s to provide a research and experimental facility for analytical chemistry, plutonium and uranium chemistry, and metallurgy. Today, research and development activities are performed involving nuclear materials. A variety of radioactive and chemical hazards are present. The CMR Building is nearing the end of its original design life and does not meet many of today`s design codes and standards. The Proposed Action for this Environmental Assessment (EA) includes structural modifications to some portions of the CMR Building which do not meet current seismic criteria for a Hazard Category 2 Facility. Also included are upgrades and improvements in building ventilation, communications, monitoring, and fire protection systems. This EA analyzes the environmental effects of construction of the proposed upgrades. The Proposed Action will have no adverse effects upon agricultural and cultural resources, wetlands and floodplains, endangered and threatened species, recreational resources, or water resources. The Proposed Action would have negligible effects on human health and transportation, and would not pose a disproportionate adverse health or environmental impact on minority or low-income populations within an 80 kilometer (50 mile) radius of the CMR Building.

  11. A Wildfire Behavior Modeling System at Los Alamos National Laboratory for Operational Applications

    SciTech Connect

    S.W. Koch; R.G.Balice

    2004-11-01

    To support efforts to protect facilities and property at Los Alamos National Laboratory from damages caused by wildfire, we completed a multiyear project to develop a system for modeling the behavior of wildfires in the Los Alamos region. This was accomplished by parameterizing the FARSITE wildfire behavior model with locally gathered data representing topography, fuels, and weather conditions from throughout the Los Alamos region. Detailed parameterization was made possible by an extensive monitoring network of permanent plots, weather towers, and other data collection facilities. We also incorporated a database of lightning strikes that can be used individually as repeatable ignition points or can be used as a group in Monte Carlo simulation exercises and in other randomization procedures. The assembled modeling system was subjected to sensitivity analyses and was validated against documented fires, including the Cerro Grande Fire. The resulting modeling system is a valuable tool for research and management. It also complements knowledge based on professional expertise and information gathered from other modeling technologies. However, the modeling system requires frequent updates of the input data layers to produce currently valid results, to adapt to changes in environmental conditions within the Los Alamos region, and to allow for the quick production of model outputs during emergency operations.

  12. Intermediate depth seismicity - a reflection seismic approach

    NASA Astrophysics Data System (ADS)

    Haberland, C.; Rietbrock, A.

    2004-12-01

    During subduction the descending oceanic lithosphere is subject to metamorphic reactions, some of them associated with the release of fluids. It is now widely accepted, that these reactions and associated dehydration processes are directly related with the generation of intermediate depth earthquakes (dehydration embrittlement). However, the structure of the layered oceanic plate at depth and the location of the earthquakes relative to structural units of the subducting plate (sources within the oceanic crust and/or in the upper oceanic mantle lithosphere?) are still not resolved yet. This is in mainly due to the fact that the observational resolution needed to address these topics (in the range of only a few kilometers) is hardly achieved in field experiments and related studies. Here we study the wavefields of intermediate depth earthquakes typically observed by temporary networks in order to assess their high-resolution potential in resolving structure of the down going slab and locus of seismicity. In particular we study whether the subducted oceanic Moho can be detected by the analysis of secondary phases of local earthquakes (near vertical reflection). Due to the irregular geometry of sources and receivers we apply an imaging technique similar to diffraction stack migration. The method is tested using synthetic data both based on 2-D finite difference simulations and 3-D kinematic ray tracing. The accuracy of the hypocenter location and onset times crucial for the successful application of stacking techniques (coherency) was achieved by the use of relatively relocated intermediate depth seismicity. Additionally, we simulate the propagation of the wavefields at larger distance (wide angle) indicating the development of guided waves traveling in the low-velocity waveguide associated with the modeled oceanic crust. We also present application on local earthquake data from the South American subduction zone.

  13. 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.

  14. Georgia-Armenia Transboarder seismicity studies

    NASA Astrophysics Data System (ADS)

    Godoladze, T.; Tvaradze, N.; Javakishvili, Z.; Elashvili, M.; Durgaryan, R.; Arakelyan, A.; Gevorgyan, M.

    2012-12-01

    In the presented study we performed Comprehensive seismic analyses for the Armenian-Georgian transboarder active seismic fault starting on Armenian territory, cutting the state boarder and having possibly northern termination on Adjara-Triealeti frontal structure in Georgia. In the scope of International projects: ISTC A-1418 "Open network of scientific Centers for mitigation risk of natural hazards in the Southern Caucasus and Central Asia" and NATO SfP- 983284 Project "Caucasus Seismic Emergency Response" in Akhalkalaki (Georgia) seismic center, Regional Summer school trainings and intensive filed investigations were conducted. Main goal was multidisciplinary study of the Javakheti fault structure and better understanding seismicity of the area. Young scientists from Turkey, Armenia, Azerbaijan and Georgia were participated in the deployment of temporal seismic network in order to monitor seisimity on the Javakheti highland and particularly delineate fault scarf and identify active seismic structures. In the scope of international collaboration the common seismic database has been created in the southern Caucasus and collected data from the field works is available now online. Javakheti highland, which is located in the central part of the Caucasus, belongs to the structure of the lesser Caucasus and represents a history of neotectonic volcanism existed in the area. Jasvakheti highland is seismicalu active region devastating from several severe earthquakes(1088, 1283, 1899…). Hypocenters located during analogue network were highly scattered and did not describe real pattern of seismicity of the highland. We relocated hypocenters of the region and improved local velocity model. The hypocenters derived from recently deployed local seismic network in the Javakheti highland, clearly identified seismically active structures. Fault plane solutions of analogue data of the Soviet times have been carefully analyzed and examined. Moment tensor inversion were preformed

  15. A Discussion on Low Seismicity in 2012 in Taiwan

    NASA Astrophysics Data System (ADS)

    Lai, T. S.; Wu, Y. M.

    2014-12-01

    In Taiwan, a significant seismic quiescence before the 1999 MW 7.6 Chi-Chi earthquake was reported by Wu and Chiao (2006). Recently, a low seismicity is also observed in 2012. There are nine months within 2012 with monthly seismicity rates low than the one standard deviation. It is worth to check that this is a seismic quiescence period before a big earthquake or other reasons. The first we checked the seismic network condition. We found some new seismic stations including the Broadband Array in Taiwan for Seismology (BATS) were incorporated within the Central Weather Bureau Seismic Network (CWBSN) since 2012. Most of those stations are located on hard rock sites which may affect the magnitude estimation. In order to reduce the impact of site effect, we collected the earthquake catalog data during the period from 1994 to 2012 to calculate the station correction for each station. There is a strong correlation between station corrections determined in this study and geological settings. Stations located on soil sites have high amplifications with negative station corrections. On the other hand, stations located on hard rock sites have low amplifications with positive station corrections. After applied the station corrections to revise ML estimation, seismicity rate obviously increases in 2012 and without low seismicity anomaly. Therefore, the reason low seismicity in 2012 is that new adding seismic stations which are installed on rock sites and lead to underestimate of the magnitude determination.

  16. 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.

  17. Seismic detection of sonic booms.

    PubMed

    Cates, Joseph E; Sturtevant, Bradford

    2002-01-01

    The pressure signals from a sonic boom will produce a small, but detectable, ground motion. The extensive seismic network in southern California, consisting of over 200 sites covering over 50000 square kilometers, is used to map primary and secondary sonic boom carpets. Data from the network is used to analyze three supersonic overflights in the western United States. The results are compared to ray-tracing computations using a realistic model of the stratified atmospheric at the time of the measurements. The results show sonic boom ground exposure under the real atmosphere is much larger than previously expected or predicted by ray tracing alone. Finally, seismic observations are used to draw some inferences on the origin of a set of "mystery booms" recorded in 1992-1993 in southern California. PMID:11837967

  18. Technological Advancements: Seismic Refraction on the Pajarito Plateau, Northern New Mexico.

    SciTech Connect

    Nisengard, J. E.; Ferguson, J. F.; Hinz, E.; Isaacson, J.; Gauthier, Rory P.

    2005-01-01

    Geophysical techniques can be used for non-invasive surveys at archaeological sites. Seismic refraction is one such technology that has many potential applications, although it has been under-utilized. It is an inexpensive, efficient way to characterize subsurface deposits, especially at sites in shallow contexts over bedrock. Archaeologists and geophysicists participating in the Summer of Applied Geophysics Experience (SAGE), from Los Alamos National Laboratory (LANL), and Bandelier National Monument are working together to characterize Ancestral Pueblo (A.D. 1200 to 1600) sites. We present the results from three seismic refraction surveys and provide an overview of how seismic refraction works.

  19. Fennoscandian lithosphere - electromagnetic and seismic constraints

    NASA Astrophysics Data System (ADS)

    Korja, T.; Kozlovskaya, E.; Smirnov, M.

    2009-04-01

    Knowledge of the present-day structure of the Earth's mantle is essential to our understanding of plate tectonics as well as Earth's thermomechanical evolution over long periods of geological time. Several factors including temperature, chemical composition, presence of partial melt or water influence seismic velocities and electrical conductivity in the upper mantle. Similarly, anisotropy may have a profound effect on seismic and magnetotelluric observations. During last ten years, several large scale multinational and national seismic and magnetotelluric experiments have been carried out in Fennnoscandia including e.g. the SVEKALAPKO seismic tomography experiment, Swedish National Seismic Network (SNSN) array monitoring, BEAR and EMMA magnetotelluric array studies and magnetotelluric profiling such as TOR and Jamtland. Altogether these studies cover most of Fennoscandia and make it possible to correlate two different data sets and to study lithospheric structures in Fennoscandia. In particular, we will compare the thickness of the lithosphere obtained from seismic anisotropy studies and from magnetotelluric studies. We will also correlate spatially sparse indications on seismic reflectors and electrically conducting layers in the mantle lithosphere. Finally, we aim to compare directly absolute values of seismic velocity and electrical conductivity.

  20. 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.

  1. Seismic excitation by space shuttles

    USGS Publications Warehouse

    Kanamori, H.; Mori, J.; Sturtevant, B.; Anderson, D.L.; Heaton, T.

    1992-01-01

    Shock waves generated by the space shuttles Columbia (August 13, 1989), Atlantis (April 11, 1991) and Discovery (September 18, 1991) on their return to Edwards Air Force Base, California, were recorded by TERRAscope (Caltech's broadband seismic network), the Caltech-U.S.G.S Southern California Seismic Network (SCSN), and the University of Southern California (USC) Los Angeles Basin Seismic Network. The spatial pattern of the arrival times exhibits hyperbolic shock fronts from which the path, velocity and altitude of the space shuttle could be determined. The shock wave was acoustically coupled to the ground, converted to a seismic wave, and recorded clearly at the broadband TERRAscope stations. The acoustic coupling occurred very differently depending on the conditions of the Earth's surface surrounding the station. For a seismic station located on hard bedrock, the shock wave (N wave) was clearly recorded with little distortion. Aside from the N wave, very little acoustic coupling of the shock wave energy to the ground occurred at these sites. The observed N wave record was used to estimate the overpressure of the shock wave accurately; a pressure change of 0.5 to 2.2 mbars was obtained. For a seismic station located close to the ocean or soft sedimentary basins, a significant amount of shock wave energy was transferred to the ground through acoustic coupling of the shock wave and the oceanic Rayleigh wave. A distinct topography such as a mountain range was found effective to couple the shock wave energy to the ground. Shock wave energy was also coupled to the ground very effectively through large man made structures such as high rise buildings and offshore oil drilling platforms. For the space shuttle Columbia, in particular, a distinct pulse having a period of about 2 to 3 seconds was observed, 12.5 s before the shock wave, with a broadband seismograph in Pasadena. This pulse was probably excited by the high rise buildings in downtown Los Angeles which were

  2. Nuclear Forensics at Los Alamos National Laboratory

    SciTech Connect

    Podlesak, David W; Steiner, Robert E.; Burns, Carol J.; LaMont, Stephen P.; Tandon, Lav

    2012-08-09

    The overview of this presentation is: (1) Introduction to nonproliferation efforts; (2) Scope of activities at Los Alamos National Laboratory; (3) Facilities for radioanalytical work at LANL; (4) Radiochemical characterization capabilities; and (5) Bulk chemical and materials analysis capabilities. Some conclusions are: (1) Analytical chemistry measurements on plutonium and uranium matrices are critical to numerous defense and non-defense programs including safeguards accountancy verification measurements; (2) Los Alamos National Laboratory operates capable actinide analytical chemistry and material science laboratories suitable for nuclear material forensic characterization; (3) Actinide analytical chemistry uses numerous means to validate and independently verify that measurement data quality objectives are met; and (4) Numerous LANL nuclear facilities support the nuclear material handling, preparation, and analysis capabilities necessary to evaluate samples containing nearly any mass of an actinide (attogram to kilogram levels).

  3. Seismic refraction exploration

    SciTech Connect

    Ruehle, W.H.

    1980-12-30

    In seismic exploration, refracted seismic energy is detected by seismic receivers to produce seismograms of subsurface formations. The seismograms are produced by directing seismic energy from an array of sources at an angle to be refracted by the subsurface formations and detected by the receivers. The directivity of the array is obtained by delaying the seismic pulses produced by each source in the source array.

  4. Offshore double-planed shallow seismic zone in the NE Japan forearc region revealed by sP depth phases recorded by regional networks

    NASA Astrophysics Data System (ADS)

    Gamage, Shantha S. N.; Umino, Norihito; Hasegawa, Akira; Kirby, Stephen H.

    2009-07-01

    We detected the sP depth phase at small epicentral distances of about 150 km or more in the seismograms of shallow earthquakes in the NE Japan forearc region. The focal depths of 1078 M > 3 earthquakes that occurred from 2000 to 2006 were precisely determined using the time delay of the sP phase from the initial P-wave arrival. The distribution of relocated hypocentres clearly shows the configuration of a double-planed shallow seismic zone beneath the Pacific Ocean. The upper plane has a low dip angle near the Japan Trench, increasing gradually to ~30° at approximately 100 km landward of the Japan Trench. The lower plane is approximately parallel to the upper plane, and appears to be the near-trench counterpart of the lower plane of the double-planed deep seismic zone beneath the land area. The distance between the upper and lower planes is 28-32 km, which is approximately the same as or slightly smaller than that of the double-planed deep seismic zone beneath the land area. Focal mechanism solutions of the relocated earthquakes are determined from P-wave initial motion data. Although P-wave initial motion data for these offshore events are not ideally distributed on the focal sphere, we found that the upper-plane events that occur near the Japan Trench are characterized by normal faulting, whereas lower-plane events are characterized by thrust faulting. This focal mechanism distribution is the opposite to that of the double-planed deep seismic zone beneath the land area. The characteristics of these focal mechanisms for the shallow and deep doubled-planed seismic zones can be explained by a bending-unbending model of the subducting Pacific plate. Some of relocated earthquakes took place in the source area of the 1933 Mw8.4 Sanriku earthquake at depths of 10-23 km. The available focal mechanisms for these events are characterized by normal faulting. Given that the 1933 event was a large normal-fault event that occurred along a fault plane dipping landward, the

  5. Offshore double-planed shallow seismic zone in the NE Japan forearc region revealed by sP depth phases recorded by regional networks

    USGS Publications Warehouse

    Gamage, S.S.N.; Umino, N.; Hasegawa, A.; Kirby, S.H.

    2009-01-01

    We detected the sP depth phase at small epicentral distances of about 150 km or more in the seismograms of shallow earthquakes in the NE Japan forearc region. The focal depths of 1078 M > 3 earthquakes that occurred from 2000 to 2006 were precisely determined using the time delay of the sP phase from the initial P-wave arrival. The distribution of relocated hypocentres clearly shows the configuration of a double-planed shallow seismic zone beneath the Pacific Ocean. The upper plane has a low dip angle near the Japan Trench, increasing gradually to ???30?? at approximately 100 km landward of the Japan Trench. The lower plane is approximately parallel to the upper plane, and appears to be the near-trench counterpart of the lower plane of the double-planed deep seismic zone beneath the land area. The distance between the upper and lower planes is 28-32 km, which is approximately the same as or slightly smaller than that of the double-planed deep seismic zone beneath the land area. Focal mechanism solutions of the relocated earthquakes are determined from P-wave initial motion data. Although P-wave initial motion data for these offshore events are not ideally distributed on the focal sphere, we found that the upper-plane events that occur near the Japan Trench are characterized by normal faulting, whereas lower-plane events are characterized by thrust faulting. This focal mechanism distribution is the opposite to that of the double-planed deep seismic zone beneath the land area. The characteristics of these focal mechanisms for the shallow and deep doubled-planed seismic zones can be explained by a bending-unbending model of the subducting Pacific plate. Some of relocated earthquakes took place in the source area of the 1933 Mw8.4 Sanriku earthquake at depths of 10-23 km. The available focal mechanisms for these events are characterized by normal faulting. Given that the 1933 event was a large normal-fault event that occurred along a fault plane dipping landward, the

  6. Amphibians and Reptiles of Los Alamos County

    SciTech Connect

    Teralene S. Foxx; Timothy K. Haarmann; David C. Keller

    1999-10-01

    Recent studies have shown that amphibians and reptiles are good indicators of environmental health. They live in terrestrial and aquatic environments and are often the first animals to be affected by environmental change. This publication provides baseline information about amphibians and reptiles that are present on the Pajarito Plateau. Ten years of data collection and observations by researchers at Los Alamos National Laboratory, the University of New Mexico, the New Mexico Department of Game and Fish, and hobbyists are represented.

  7. Los Alamos Novel Rocket Design Flight Tested

    ScienceCinema

    Tappan, Bryce

    2015-01-05

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  8. Los Alamos Novel Rocket Design Flight Tested

    SciTech Connect

    Tappan, Bryce

    2014-10-23

    Los Alamos National Laboratory scientists recently flight tested a new rocket design that includes a high-energy fuel and a motor design that also delivers a high degree of safety. Researchers will now work to scale-up the design, as well as explore miniaturization of the system, in order to exploit all potential applications that would require high-energy, high-velocity, and correspondingly high safety margins.

  9. Los Alamos Team Demonstrates Bottle Scanner Technology

    SciTech Connect

    Espy, Michelle; Schultz, Larry

    2014-05-06

    Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

  10. The Los Alamos accelerator code group

    SciTech Connect

    Krawczyk, F.L.; Billen, J.H.; Ryne, R.D.; Takeda, Harunori; Young, L.M.

    1995-05-01

    The Los Alamos Accelerator Code Group (LAACG) is a national resource for members of the accelerator community who use and/or develop software for the design and analysis of particle accelerators, beam transport systems, light sources, storage rings, and components of these systems. Below the authors describe the LAACG`s activities in high performance computing, maintenance and enhancement of POISSON/SUPERFISH and related codes and the dissemination of information on the INTERNET.

  11. Los Alamos Team Demonstrates Bottle Scanner Technology

    ScienceCinema

    Espy, Michelle; Schultz, Larry

    2014-06-02

    Los Alamos scientists are demonstrating a Nuclear Magnetic Resonance Imaging (NMR) technology that may provide a breakthrough for screening liquids at airport security. By adding low-power X-ray data to the NMR mix, scientists believe they have unlocked a new detection technology. Funded in part by the Department of Homeland Security's Science and Technology Directorate, the new technology is called MagRay.

  12. Los Alamos National Laboratory Facility Review

    SciTech Connect

    Nelson, Ronald Owen

    2015-06-05

    This series of slides depicts the Los Alamos Neutron Science Center (LANSCE). The Center's 800-MeV linac produces H+ and H- beams as well as beams of moderated (cold to 1 MeV) and unmoderated (0.1 to 600 MeV) neutrons. Experimental facilities and their capabilities and characteristics are outlined. Among these are LENZ, SPIDER, and DANCE.

  13. Los Alamos synchronous orbit data set

    SciTech Connect

    Baker, D.N.; Higbie, P.R.; Belian, R.D.; Hones, E.W.; Klebesadel, R.W.

    1981-01-01

    Energetic electron (30-15000 keV) and proton 145 keV to 150 MeV) measurements made by Los Alamos National Laboratory sensors at geostationary orbit (6.6 R/sub E/) are summarized. The instrumentation employed and the satellite positions are described. The spacecraft have been variously located, but in their present configuration the Los Alamos satellites designated 1976-059, 1977-007, and 1979-053 are located, respectively, at approx. 70/sup 0/W, approx. 70/sup 0/E, and approx. 135/sup 0/W longitude. Several examples of the high temporal and full three-dimensional spatial measurement capabilities of these instruments are illustrated by examples from the published literature. Discussion is also given for the Los Alamos Synoptic Data Set (SDS) which gives a broad overview of the Los Alamos geostationary orbit measurements. The SDS data are plotted in terms of daily average spectra, 3-hour local time averages, and in a variety of statistical formats. The data summarize conditions from mid-1976 through 1978 (S/C 1976-059) and from early 1977 through 1978 (S/C 1977-007). The SDS compilations presented correspond to measurements at 35/sup 0/W, 70/sup 0/W, and 135/sup 0/W geographic longitude and thus are indicative of conditions at 9/sup 0/, 11/sup 0/, and 4.8/sup 0/ geomagnetic latitude, respectively. The bulk of the SDS report presents data plots which are organized according to Carrington solar rotations and, as such, the data are readily comparable to solar rotation-dependent interplanetary conditions. Potential applications of the Synoptic Data Set (available to all interested users in June 1981) are discussed.

  14. Status of the Los Alamos Anger camera

    SciTech Connect

    Seeger, P.A.; Nutter, M.J.

    1985-01-01

    Results of preliminary tests of the neutron Anger camera being developed at Los Alamos are presented. This detector uses a unique encoding scheme involving parellel processing of multiple receptive fields. Design goals have not yet been met, but the results are very encouraging and improvements in the test procedures are expected to show that the detector will be ready for use on a small-angle scattering instrument next year. 3 refs., 4 figs.

  15. Critical partnerships: Los Alamos, universities, and industry

    SciTech Connect

    Berger, C.L.

    1997-04-01

    Los Alamos National Laboratory, situated 35 miles northwest of Santa Fe, NM, is one of the Department of Energy`s three Defense Programs laboratories. It encompasses 43 square miles, employees approximately 10,000 people, and has a budget of approximately $1.1B in FY97. Los Alamos has a strong post-cold war mission, that of reducing the nuclear danger. But even with that key role in maintaining the nation`s security, Los Alamos views partnerships with universities and industry as critical to its future well being. Why is that? As the federal budget for R&D comes under continued scrutiny and certain reduction, we believe that the triad of science and technology contributors to the national system of R&D must rely on and leverage each others capabilities. For us this means that we will rely on these partners to help us in 5 key ways: We expect that partnerships will help us maintain and enhance our core competencies. In doing so, we will be able to attract the best scientists and engineers. To keep on the cutting edge of research and development, we have found that partnerships maintain the excellence of staff through new and exciting challenges. Additionally, we find that from our university and corporate partners we often learn and incorporate {open_quotes}best practices{close_quotes} in organizational management and operations. Finally, we believe that a strong national system of R&D will ensure and enhance our ability to generate revenues.

  16. Los Alamos National Laboratory Building Cost Index

    SciTech Connect

    Orr, H.D.; Lemon, G.D.

    1983-01-01

    The Los Alamos National Laboratory Building Cost Index indicates that actual escalation since 1970 is near 10% per year. Therefore, the Laboratory will continue using a 10% per year escalation rate for construction estimates through 1985 and a slightly lower rate of 8% per year from 1986 through 1990. The computerized program compares the different elements involved in the cost of a typical construction project, which for our purposes, is a complex of office buildings and experimental laboratores. The input data used in the program consist primarily of labor costs and material and equipment costs. The labor costs are the contractural rates of the crafts workers in the Los Alamos area. For the analysis, 12 field-labor draft categories are used; each is weighted corresponding to the labor craft distribution associated with the typical construction project. The materials costs are current Los Alamos prices. Additional information sources include material and equipment quotes obtained through conversations with vendors and from trade publications. The material and equipment items separate into 17 categories for the analysis and are weighted corresponding to the material and equipment distribution associated with the typical construction project. The building cost index is compared to other national building cost indexes.

  17. Los Alamos National Laboratory building cost index

    SciTech Connect

    Orr, H.D.; Lemon, G.D.

    1982-10-01

    The Los Alamos National Laboratory Building Cost Index indicates that actual escalation since 1970 is near 10% per year. Therefore, the Laboratory will continue using a 10% per year escalation rate for construction estimates through 1985 and a slightly lower rate of 8% per year from 1986 through 1990. The computerized program compares the different elements involved in the cost of a typical construction project, which for our purposes, is a complex of office buildings and experimental laboratories. The input data used in the