WorldWideScience

Sample records for seismology

  1. Seismology

    International Nuclear Information System (INIS)

    1980-01-01

    The Norwegian Seismic Array (NORSAR) has in 1979 worked mainly on reports and investigations for the seismological expert group established in 1976 by the UN Disarmament Committee in Geneva. One of NORSAR's staff is scientific secretary for the group. Reports published by the group in 1978 and 1979 proposed a global surveillance system for nuclear explosions and NORSAR as one of the largest stations will play a central role in the proposed network. A number of other tasks have been performed by NORSAR in connection with the seismology and tectonics of the Norwegian continental shelf, a projected dam in Tanzania, a dam in S.W.Norway, seismic activityin Spitzbergen and ore prospecting in N.Norway. (JIW)

  2. Extraterrestrial seismology

    CERN Document Server

    Tong, Vincent C H

    2015-01-01

    Seismology is a highly effective tool for investigating the internal structure of the Earth. Similar techniques have also successfully been used to study other planetary bodies (planetary seismology), the Sun (helioseismology), and other stars (asteroseismology). Despite obvious differences between stars and planetary bodies, these disciplines share many similarities and together form a coherent field of scientific research. This unique book takes a transdisciplinary approach to seismology and seismic imaging, reviewing the most recent developments in these extraterrestrial contexts. With contributions from leading scientists, this timely volume systematically outlines the techniques used in observation, data processing, and modelling for asteroseismology, helioseismology, and planetary seismology, drawing comparisons with seismic methods used in geophysics. Important recent discoveries in each discipline are presented. With an emphasis on transcending the traditional boundaries of astronomy, solar, planetary...

  3. Rotational seismology

    Science.gov (United States)

    Lee, William H K.

    2016-01-01

    Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

  4. Citizen Seismology

    Science.gov (United States)

    Bossu, Rémy; Gilles, Sébastien; Mazet-Roux, Gilles; Kamb, Linus; Frobert, Laurent

    2010-05-01

    In science, projects which involve volunteers for observations, measurements, computation are grouped under the term, Citizen Science. They range from bird or planet census to distributing computing on volonteers's computer. Over the last five years, the EMSC has been developing tools and strategy to collect information on earthquake's impact from the first persons to be informed, i.e. the witnesses. By extension, it is named Citizen Seismology. The European Mediterranean Seismological Centre (EMSC), a scientific not-for-profit NGO, benefits from the high visibility of its rapid earthquake information services (www.emsc-csem.org) which attract an average of more than half a million visits a month from 160 countries. Witnesses converge to its site within a couple of minutes of earthquake's occurrence to find out information about the cause of the shaking they have just been through. The convergence generates brutal increases of hit rate which can be automatically detected. They are often the first indication about the occurrence of a felt event. Witnesses' locations are determined from their IP addresses. Localities exhibiting statistically significant increase of traffic are mapped to produce the "felt map". This map available within 5 to 8 minutes of the earthquake's occurrence represents the area where the event was felt. It is the fastest way to collect in-situ information on the consequences of an earthquake. Widespread damage region are expected to be mapped through a significant lack or absence of visitors. A second tool involving the visitors is an online macroseismic questionnaire available in 21 languages. It complements the felt maps as it can describes the level of shaking or damage, but is only available in 90 to 120 minutes. Witnesses can also share their pictures of damage. They used it also to provide us exceptional pictures of transient phenomena. With the University of Edinburgh, we are finalising a prototype named ShakemApple, linking Apple

  5. Volcano seismology

    Science.gov (United States)

    Chouet, B.

    2003-01-01

    A fundamental goal of volcano seismology is to understand active magmatic systems, to characterize the configuration of such systems, and to determine the extent and evolution of source regions of magmatic energy. Such understanding is critical to our assessment of eruptive behavior and its hazardous impacts. With the emergence of portable broadband seismic instrumentation, availability of digital networks with wide dynamic range, and development of new powerful analysis techniques, rapid progress is being made toward a synthesis of high-quality seismic data to develop a coherent model of eruption mechanics. Examples of recent advances are: (1) high-resolution tomography to image subsurface volcanic structures at scales of a few hundred meters; (2) use of small-aperture seismic antennas to map the spatio-temporal properties of long-period (LP) seismicity; (3) moment tensor inversions of very-long-period (VLP) data to derive the source geometry and mass-transport budget of magmatic fluids; (4) spectral analyses of LP events to determine the acoustic properties of magmatic and associated hydrothermal fluids; and (5) experimental modeling of the source dynamics of volcanic tremor. These promising advances provide new insights into the mechanical properties of volcanic fluids and subvolcanic mass-transport dynamics. As new seismic methods refine our understanding of seismic sources, and geochemical methods better constrain mass balance and magma behavior, we face new challenges in elucidating the physico-chemical processes that cause volcanic unrest and its seismic and gas-discharge manifestations. Much work remains to be done toward a synthesis of seismological, geochemical, and petrological observations into an integrated model of volcanic behavior. Future important goals must include: (1) interpreting the key types of magma movement, degassing and boiling events that produce characteristic seismic phenomena; (2) characterizing multiphase fluids in subvolcanic

  6. Seismology of the Jupiter

    International Nuclear Information System (INIS)

    Vorontsov, S.V.; Gudkova, T.V.; Zharkov, V.N.

    1989-01-01

    The structure and diagnostic properties of the spectrum of free oscillations of the models of the Jupiter are discussed. The spectrum is very sensitive to the properties of the inner core and density discontinuities in the interior of the planet. It is shown that in seismology of the Jupiter unlike to solar seismology, it is not possible to use the asymptotic theory for investigation of the high-frequency part of the acoustic spectrum

  7. Jesuits in seismology

    Science.gov (United States)

    Linehan, D.

    1984-01-01

    Jesuits have been involved with scientific endeavors since the 16th century, although their association with seismology is more recent. What impelled Jesuit priests to also become seismologists is am matter of conjecture. Certainly the migration of missionaries to various parts of the world must have resulted in queries to their fellow Jesuits in Europe. What caused earthquakes? Could they be predicted? Were they connected with the weather?

  8. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.

    2015-08-19

    We use controlled noise seismology (CNS) to generate surface waves, where we continuously record seismic data while generating artificial noise along the profile line. To generate the CNS data we drove a vehicle around the geophone line and continuously recorded the generated noise. The recorded data set is then correlated over different time windows and the correlograms are stacked together to generate the surface waves. The virtual shot gathers reveal surface waves with moveout velocities that closely approximate those from active source shot gathers.

  9. The Colombia Seismological Network

    Science.gov (United States)

    Blanco Chia, J. F.; Poveda, E.; Pedraza, P.

    2013-05-01

    The latest seismological equipment and data processing instrumentation installed at the Colombia Seismological Network (RSNC) are described. System configuration, network operation, and data management are discussed. The data quality and the new seismological products are analyzed. The main purpose of the network is to monitor local seismicity with a special emphasis on seismic activity surrounding the Colombian Pacific and Caribbean oceans, for early warning in case a Tsunami is produced by an earthquake. The Colombian territory is located at the South America northwestern corner, here three tectonic plates converge: Nazca, Caribbean and the South American. The dynamics of these plates, when resulting in earthquakes, is continuously monitored by the network. In 2012, the RSNC registered in 2012 an average of 67 events per day; from this number, a mean of 36 earthquakes were possible to be located well. In 2010 the network was also able to register an average of 67 events, but it was only possible to locate a mean of 28 earthquakes daily. This difference is due to the expansion of the network. The network is made up of 84 stations equipped with different kind of broadband 40s, 120s seismometers, accelerometers and short period 1s sensors. The signal is transmitted continuously in real-time to the Central Recording Center located at Bogotá, using satellite, telemetry, and Internet. Moreover, there are some other stations which are required to collect the information in situ. Data is recorded and processed digitally using two different systems, EARTHWORM and SEISAN, which are able to process and share the information between them. The RSNC has designed and implemented a web system to share the seismological data. This innovative system uses tools like Java Script, Oracle and programming languages like PHP to allow the users to access the seismicity registered by the network almost in real time as well as to download the waveform and technical details. The coverage

  10. Controlled Noise Seismology

    KAUST Repository

    Hanafy, Sherif M.; AlTheyab, Abdullah; Schuster, Gerard T.

    2015-01-01

    We use controlled noise seismology (CNS) to generate surface waves, where we continuously record seismic data while generating artificial noise along the profile line. To generate the CNS data we drove a vehicle around the geophone line and continuously recorded the generated noise. The recorded data set is then correlated over different time windows and the correlograms are stacked together to generate the surface waves. The virtual shot gathers reveal surface waves with moveout velocities that closely approximate those from active source shot gathers.

  11. Geology and seismology

    International Nuclear Information System (INIS)

    Schneider, J.F.; Blanc, B.

    1980-01-01

    For the construction of nuclear power stations, comprehensive site investigations are required to assure the adequacy and suitability of the site under consideration, as well as to establish the basic design data for designing and building the plant. The site investigations cover mainly the following matters: geology, seismology, hydrology, meteorology. Site investigations for nuclear power stations are carried out in stages in increasing detail and to an appreciable depth in order to assure the soundness of the project, and, in particular, to determine all measures required to assure the safety of the nuclear power station and the protection of the population against radiation exposure. The aim of seismological investigations is to determine the strength of the vibratory ground motion caused by an expected strong earthquake in order to design the plant resistant enough to take up these vibrations. In addition, secondary effects of earthquakes, such as landslides, liquefaction, surface faulting, etc. must be studied. For seashore sites, the tsunami risk must be evaluated. (orig.)

  12. Forensic seismology revisited

    Science.gov (United States)

    Douglas, A.

    2007-01-01

    contrast simple, comprising one or two cycles of large amplitude followed by a low-amplitude coda. Earthquake signals on the other hand were often complex with numerous arrivals of similar amplitude spread over 35 s or more. It therefore appeared that earthquakes could be recognised on complexity. Later however, complex explosion signals were observed which reduced the apparent effectiveness of complexity as a criterion for identifying earthquakes. Nevertheless, the AWE Group concluded that for many paths to teleseismic distances, Earth is transparent for P signals and this provides a window through which source differences will be most clearly seen. Much of the research by the Group has focused on understanding the influence of source type on P seismograms recorded at teleseismic distances. Consequently the paper concentrates on teleseismic methods of distinguishing between explosions and earthquakes. One of the most robust criteria for discriminating between earthquakes and explosions is the m b : M s criterion which compares the amplitudes of the SP P waves as measured by the body-wave magnitude m b, and the long-period (LP: ˜0.05 Hz) Rayleigh-wave amplitude as measured by the surface-wave magnitude M s; the P and Rayleigh waves being the main wave types used in forensic seismology. For a given M s, the m b for explosions is larger than for most earthquakes. The criterion is difficult to apply however, at low magnitude (say m b fail. Consequently the AWE Group in cooperation with the University of Cambridge used seismogram modelling to try and understand what controls complexity of SP P seismograms, and to put the m b : M s criterion on a theoretical basis. The results of this work show that the m b : M s criterion is robust because several factors contribute to the separation of earthquakes and explosions. The principal reason for the separation however, is that for many orientations of the earthquake source there is at least one P nodal plane in the teleseismic

  13. Bucharest urban seismology

    International Nuclear Information System (INIS)

    Balan, Stefan Florin; Ritter, Joachim R.R.

    2005-01-01

    An important project was carried out in Bucharest area by the National Institute of Research-Development for Earth Physics and Collaborative Research Center 461 (CRC 461) Geophysical Institute from the University of Karlsruhe (Germany) in the period October 2003 - August 2004. The project consists of an array of 33 stations, uniformly arranged in the city of Bucharest and in the outskirts (Magurele, Voluntari, Otopeni, Buftea, etc). The station functioned 24 h/day for a period of 10 months. The number of functioning stations had a little variation in time, some of them had to be moved because some sites became improper in time. The sensors used by the stations were of the type: STS - 2, LE - 3D, 4OT, 3ESP and KS2000. The performance of continuous recording was possible by using on each station a hard disk drive of 120 Gb, which gives independence of 3 month. For preventing some accidental electric power stops a rechargeable battery on each station was used . A service was performed for each station every month to avoid accidental stops, which consisted usually of mechanical bumps. All the recorded data by the stations was saved on DVSs, the final number being around 140. This project helped gathering a large number of seismological data for the city of Bucharest and outskirts from seismic events of magnitude of 4, 3, 2 and ambient noise. (authors)

  14. Seismology Outreach in Alaska

    Science.gov (United States)

    Gardine, L.; Tape, C.; West, M. E.

    2014-12-01

    Despite residing in a state with 75% of North American earthquakes and three of the top 15 ever recorded, most Alaskans have limited knowledge about the science of earthquakes. To many, earthquakes are just part of everyday life, and to others, they are barely noticed until a large event happens, and often ignored even then. Alaskans are rugged, resilient people with both strong independence and tight community bonds. Rural villages in Alaska, most of which are inaccessible by road, are underrepresented in outreach efforts. Their remote locations and difficulty of access make outreach fiscally challenging. Teacher retention and small student bodies limit exposure to science and hinder student success in college. The arrival of EarthScope's Transportable Array, the 50th anniversary of the Great Alaska Earthquake, targeted projects with large outreach components, and increased community interest in earthquake knowledge have provided opportunities to spread information across Alaska. We have found that performing hands-on demonstrations, identifying seismological relevance toward career opportunities in Alaska (such as natural resource exploration), and engaging residents through place-based experience have increased the public's interest and awareness of our active home.

  15. Seismological Constraints on Geodynamics

    Science.gov (United States)

    Lomnitz, C.

    2004-12-01

    Earth is an open thermodynamic system radiating heat energy into space. A transition from geostatic earth models such as PREM to geodynamical models is needed. We discuss possible thermodynamic constraints on the variables that govern the distribution of forces and flows in the deep Earth. In this paper we assume that the temperature distribution is time-invariant, so that all flows vanish at steady state except for the heat flow Jq per unit area (Kuiken, 1994). Superscript 0 will refer to the steady state while x denotes the excited state of the system. We may write σ 0=(J{q}0ṡX{q}0)/T where Xq is the conjugate force corresponding to Jq, and σ is the rate of entropy production per unit volume. Consider now what happens after the occurrence of an earthquake at time t=0 and location (0,0,0). The earthquake introduces a stress drop Δ P(x,y,z) at all points of the system. Response flows are directed along the gradients toward the epicentral area, and the entropy production will increase with time as (Prigogine, 1947) σ x(t)=σ 0+α {1}/(t+β )+α {2}/(t+β )2+etc A seismological constraint on the parameters may be obtained from Omori's empirical relation N(t)=p/(t+q) where N(t) is the number of aftershocks at time t following the main shock. It may be assumed that p/q\\sim\\alpha_{1}/\\beta times a constant. Another useful constraint is the Mexican-hat geometry of the seismic transient as obtained e.g. from InSAR radar interferometry. For strike-slip events such as Landers the distribution of \\DeltaP is quadrantal, and an oval-shaped seismicity gap develops about the epicenter. A weak outer triggering maxiμm is found at a distance of about 17 fault lengths. Such patterns may be extracted from earthquake catalogs by statistical analysis (Lomnitz, 1996). Finally, the energy of the perturbation must be at least equal to the recovery energy. The total energy expended in an aftershock sequence can be found approximately by integrating the local contribution over

  16. Mathematical treatment of seismologic data

    International Nuclear Information System (INIS)

    Gama, C.A.J.V.D. da

    The principle methods of seismologic data treatment with application in engineering design, emphasizing the need for the utilization of reliable data, appropriate algorithims and rigorous calculations so that correct results and valid conclusions be achieved, are examined. (E.G.) [pt

  17. Seismological programs in Costa Rica

    Science.gov (United States)

    Montero, W.; Spall, Henry

    1983-01-01

    At the beginning of the 1970's, a series of programs in seismology were initiated by different Costa Rican institutions, and some of these programs are still in the process of development. The institutions are Insituto Costaricense de Electricidad (ICE)- The Costa Rica Institute of Electricity

  18. Web Based Seismological Monitoring (wbsm)

    Science.gov (United States)

    Giudicepietro, F.; Meglio, V.; Romano, S. P.; de Cesare, W.; Ventre, G.; Martini, M.

    Over the last few decades the seismological monitoring systems have dramatically improved tanks to the technological advancements and to the scientific progresses of the seismological studies. The most modern processing systems use the network tech- nologies to realize high quality performances in data transmission and remote controls. Their architecture is designed to favor the real-time signals analysis. This is, usually, realized by adopting a modular structure that allow to easy integrate any new cal- culation algorithm, without affecting the other system functionalities. A further step in the seismic processing systems evolution is the large use of the web based appli- cations. The web technologies can be an useful support for the monitoring activities allowing to automatically publishing the results of signals processing and favoring the remote access to data, software systems and instrumentation. An application of the web technologies to the seismological monitoring has been developed at the "Os- servatorio Vesuviano" monitoring center (INGV) in collaboration with the "Diparti- mento di Informatica e Sistemistica" of the Naples University. A system named Web Based Seismological Monitoring (WBSM) has been developed. Its main objective is to automatically publish the seismic events processing results and to allow displaying, analyzing and downloading seismic data via Internet. WBSM uses the XML tech- nology for hypocentral and picking parameters representation and creates a seismic events data base containing parametric data and wave-forms. In order to give tools for the evaluation of the quality and reliability of the published locations, WBSM also supplies all the quality parameters calculated by the locating program and allow to interactively display the wave-forms and the related parameters. WBSM is a modular system in which the interface function to the data sources is performed by two spe- cific modules so that to make it working in conjunction with a

  19. Global teaching of global seismology

    Science.gov (United States)

    Stein, S.; Wysession, M.

    2005-12-01

    Our recent textbook, Introduction to Seismology, Earthquakes, & Earth Structure (Blackwell, 2003) is used in many countries. Part of the reason for this may be our deliberate attempt to write the book for an international audience. This effort appears in several ways. We stress seismology's long tradition of global data interchange. Our brief discussions of the science's history illustrate the contributions of scientists around the world. Perhaps most importantly, our discussions of earthquakes, tectonics, and seismic hazards take a global view. Many examples are from North America, whereas others are from other areas. Our view is that non-North American students should be exposed to North American examples that are type examples, and that North American students should be similarly exposed to examples elsewhere. For example, we illustrate how the Euler vector geometry changes a plate boundary from spreading, to strike-slip, to convergence using both the Pacific-North America boundary from the Gulf of California to Alaska and the Eurasia-Africa boundary from the Azores to the Mediterranean. We illustrate diffuse plate boundary zones using western North America, the Andes, the Himalayas, the Mediterranean, and the East Africa Rift. The subduction zone discussions examine Japan, Tonga, and Chile. We discuss significant earthquakes both in the U.S. and elsewhere, and explore hazard mitigation issues in different contexts. Both comments from foreign colleagues and our experience lecturing overseas indicate that this approach works well. Beyond the specifics of our text, we believe that such a global approach is facilitated by the international traditions of the earth sciences and the world youth culture that gives students worldwide common culture. For example, a video of the scene in New Madrid, Missouri that arose from a nonsensical earthquake prediction in 1990 elicits similar responses from American and European students.

  20. Seismology and space-based geodesy

    Science.gov (United States)

    Tralli, David M.; Tajima, Fumiko

    1993-01-01

    The potential of space-based geodetic measurement of crustal deformation in the context of seismology is explored. The achievements of seismological source theory and data analyses, mechanical modeling of fault zone behavior, and advances in space-based geodesy are reviewed, with emphasis on realizable contributions of space-based geodetic measurements specifically to seismology. The fundamental relationships between crustal deformation associated with an earthquake and the geodetically observable data are summarized. The response and spatial and temporal resolution of the geodetic data necessary to understand deformation at various phases of the earthquake cycle is stressed. The use of VLBI, SLR, and GPS measurements for studying global geodynamics properties that can be investigated to some extent with seismic data is discussed. The potential contributions of continuously operating strain monitoring networks and globally distributed geodetic observatories to existing worldwide modern digital seismographic networks are evaluated in reference to mutually addressable problems in seismology, geophysics, and tectonics.

  1. Bulgarian National Digital Seismological Network

    Science.gov (United States)

    Dimitrova, L.; Solakov, D.; Nikolova, S.; Stoyanov, S.; Simeonova, S.; Zimakov, L. G.; Khaikin, L.

    2011-12-01

    The Bulgarian National Digital Seismological Network (BNDSN) consists of a National Data Center (NDC), 13 stations equipped with RefTek High Resolution Broadband Seismic Recorders - model DAS 130-01/3, 1 station equipped with Quanterra 680 and broadband sensors and accelerometers. Real-time data transfer from seismic stations to NDC is realized via Virtual Private Network of the Bulgarian Telecommunication Company. The communication interruptions don't cause any data loss at the NDC. The data are backed up in the field station recorder's 4Mb RAM memory and are retransmitted to the NDC immediately after the communication link is re-established. The recorders are equipped with 2 compact flash disks able to save more than 1 month long data. The data from the flash disks can be downloaded remotely using FTP. The data acquisition and processing hardware redundancy at the NDC is achieved by two clustered SUN servers and two Blade Workstations. To secure the acquisition, processing and data storage processes a three layer local network is designed at the NDC. Real-time data acquisition is performed using REFTEK's full duplex error-correction protocol RTPD. Data from the Quanterra recorder and foreign stations are fed into RTPD in real-time via SeisComP/SeedLink protocol. Using SeisComP/SeedLink software the NDC transfers real-time data to INGV-Roma, NEIC-USA, ORFEUS Data Center. Regional real-time data exchange with Romania, Macedonia, Serbia and Greece is established at the NDC also. Data processing is performed by the Seismic Network Data Processor (SNDP) software package running on the both Servers. SNDP includes subsystems: Real-time subsystem (RTS_SNDP) - for signal detection; evaluation of the signal parameters; phase identification and association; source estimation; Seismic analysis subsystem (SAS_SNDP) - for interactive data processing; Early warning subsystem (EWS_SNDP) - based on the first arrived P-phases. The signal detection process is performed by

  2. High-performance computing in seismology

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    The scientific, technical, and economic importance of the issues discussed here presents a clear agenda for future research in computational seismology. In this way these problems will drive advances in high-performance computing in the field of seismology. There is a broad community that will benefit from this work, including the petroleum industry, research geophysicists, engineers concerned with seismic hazard mitigation, and governments charged with enforcing a comprehensive test ban treaty. These advances may also lead to new applications for seismological research. The recent application of high-resolution seismic imaging of the shallow subsurface for the environmental remediation industry is an example of this activity. This report makes the following recommendations: (1) focused efforts to develop validated documented software for seismological computations should be supported, with special emphasis on scalable algorithms for parallel processors; (2) the education of seismologists in high-performance computing technologies and methodologies should be improved; (3) collaborations between seismologists and computational scientists and engineers should be increased; (4) the infrastructure for archiving, disseminating, and processing large volumes of seismological data should be improved.

  3. Statistical Seismology and Induced Seismicity

    Science.gov (United States)

    Tiampo, K. F.; González, P. J.; Kazemian, J.

    2014-12-01

    While seismicity triggered or induced by natural resources production such as mining or water impoundment in large dams has long been recognized, the recent increase in the unconventional production of oil and gas has been linked to rapid rise in seismicity in many places, including central North America (Ellsworth et al., 2012; Ellsworth, 2013). Worldwide, induced events of M~5 have occurred and, although rare, have resulted in both damage and public concern (Horton, 2012; Keranen et al., 2013). In addition, over the past twenty years, the increase in both number and coverage of seismic stations has resulted in an unprecedented ability to precisely record the magnitude and location of large numbers of small magnitude events. The increase in the number and type of seismic sequences available for detailed study has revealed differences in their statistics that previously difficult to quantify. For example, seismic swarms that produce significant numbers of foreshocks as well as aftershocks have been observed in different tectonic settings, including California, Iceland, and the East Pacific Rise (McGuire et al., 2005; Shearer, 2012; Kazemian et al., 2014). Similarly, smaller events have been observed prior to larger induced events in several occurrences from energy production. The field of statistical seismology has long focused on the question of triggering and the mechanisms responsible (Stein et al., 1992; Hill et al., 1993; Steacy et al., 2005; Parsons, 2005; Main et al., 2006). For example, in most cases the associated stress perturbations are much smaller than the earthquake stress drop, suggesting an inherent sensitivity to relatively small stress changes (Nalbant et al., 2005). Induced seismicity provides the opportunity to investigate triggering and, in particular, the differences between long- and short-range triggering. Here we investigate the statistics of induced seismicity sequences from around the world, including central North America and Spain, and

  4. Introduction: seismology and earthquake engineering in Central and South America.

    Science.gov (United States)

    Espinosa, A.F.

    1983-01-01

    Reports the state-of-the-art in seismology and earthquake engineering that is being advanced in Central and South America. Provides basic information on seismological station locations in Latin America and some of the programmes in strong-motion seismology, as well as some of the organizations involved in these activities.-from Author

  5. Satellite Remote Sensing in Seismology. A Review

    Directory of Open Access Journals (Sweden)

    Andrew A. Tronin

    2009-12-01

    Full Text Available A wide range of satellite methods is applied now in seismology. The first applications of satellite data for earthquake exploration were initiated in the ‘70s, when active faults were mapped on satellite images. It was a pure and simple extrapolation of airphoto geological interpretation methods into space. The modern embodiment of this method is alignment analysis. Time series of alignments on the Earth's surface are investigated before and after the earthquake. A further application of satellite data in seismology is related with geophysical methods. Electromagnetic methods have about the same long history of application for seismology. Stable statistical estimations of ionosphere-lithosphere relation were obtained based on satellite ionozonds. The most successful current project "DEMETER" shows impressive results. Satellite thermal infra-red data were applied for earthquake research in the next step. Numerous results have confirmed previous observations of thermal anomalies on the Earth's surface prior to earthquakes. A modern trend is the application of the outgoing long-wave radiation for earthquake research. In ‘80s a new technology—satellite radar interferometry—opened a new page. Spectacular pictures of co-seismic deformations were presented. Current researches are moving in the direction of pre-earthquake deformation detection. GPS technology is also widely used in seismology both for ionosphere sounding and for ground movement detection. Satellite gravimetry has demonstrated its first very impressive results on the example of the catastrophic Indonesian earthquake in 2004. Relatively new applications of remote sensing for seismology as atmospheric sounding, gas observations, and cloud analysis are considered as possible candidates for applications.

  6. Seismology software: state of the practice

    Science.gov (United States)

    Smith, W. Spencer; Zeng, Zheng; Carette, Jacques

    2018-05-01

    We analyzed the state of practice for software development in the seismology domain by comparing 30 software packages on four aspects: product, implementation, design, and process. We found room for improvement in most seismology software packages. The principal areas of concern include a lack of adequate requirements and design specification documents, a lack of test data to assess reliability, a lack of examples to get new users started, and a lack of technological tools to assist with managing the development process. To assist going forward, we provide recommendations for a document-driven development process that includes a problem statement, development plan, requirement specification, verification and validation (V&V) plan, design specification, code, V&V report, and a user manual. We also provide advice on tool use, including issue tracking, version control, code documentation, and testing tools.

  7. Seismology software: state of the practice

    Science.gov (United States)

    Smith, W. Spencer; Zeng, Zheng; Carette, Jacques

    2018-02-01

    We analyzed the state of practice for software development in the seismology domain by comparing 30 software packages on four aspects: product, implementation, design, and process. We found room for improvement in most seismology software packages. The principal areas of concern include a lack of adequate requirements and design specification documents, a lack of test data to assess reliability, a lack of examples to get new users started, and a lack of technological tools to assist with managing the development process. To assist going forward, we provide recommendations for a document-driven development process that includes a problem statement, development plan, requirement specification, verification and validation (V&V) plan, design specification, code, V&V report, and a user manual. We also provide advice on tool use, including issue tracking, version control, code documentation, and testing tools.

  8. Strategic decision analysis applied to borehole seismology

    International Nuclear Information System (INIS)

    Menke, M.M.; Paulsson, B.N.P.

    1994-01-01

    Strategic Decision Analysis (SDA) is the evolving body of knowledge on how to achieve high quality in the decision that shapes an organization's future. SDA comprises philosophy, process concepts, methodology, and tools for making good decisions. It specifically incorporates many concepts and tools from economic evaluation and risk analysis. Chevron Petroleum Technology Company (CPTC) has applied SDA to evaluate and prioritize a number of its most important and most uncertain R and D projects, including borehole seismology. Before SDA, there were significant issues and concerns about the value to CPTC of continuing to work on borehole seismology. The SDA process created a cross-functional team of experts to structure and evaluate this project. A credible economic model was developed, discrete risks and continuous uncertainties were assessed, and an extensive sensitivity analysis was performed. The results, even applied to a very restricted drilling program for a few years, were good enough to demonstrate the value of continuing the project. This paper explains the SDA philosophy concepts, and process and demonstrates the methodology and tools using the borehole seismology project example. SDA is useful in the upstream industry not just in the R and D/technology decisions, but also in major exploration and production decisions. Since a major challenge for upstream companies today is to create and realize value, the SDA approach should have a very broad applicability

  9. Rotational Seismology Workshop of February 2006

    Science.gov (United States)

    Evans, John R.; Cochard, A.; Graizer, Vladimir; Huang, Bor-Shouh; Hudnut, Kenneth W.; Hutt, Charles R.; Igel, H.; Lee, William H.K.; Liu, Chun-Chi; Majewski, Eugeniusz; Nigbor, Robert; Safak, Erdal; Savage, William U.; Schreiber, U.; Teisseyre, Roman; Trifunac, Mihailo; Wassermann, J.; Wu, Chien-Fu

    2007-01-01

    Introduction A successful workshop titled 'Measuring the Rotation Effects of Strong Ground Motion' was held simultaneously in Menlo Park and Pasadena via video conference on 16 February 2006. The purpose of the Workshop and this Report are to summarize existing data and theory and to explore future challenges for rotational seismology, including free-field strong motion, structural strong motion, and teleseismic motions. We also forged a consensus on the plan of work to be pursued by this international group in the near term. At this first workshop were 16 participants in Menlo Park, 13 in Pasadena, and a few on the telephone. It was organized by William H. K. Lee and John R. Evans and chaired by William U. Savage in Menlo Park and by Kenneth W. Hudnut in Pasadena. Its agenda is given in the Appendix. This workshop and efforts in Europe led to the creation of the International Working Group on Rotational Seismology (IWGoRS), an international volunteer group providing forums for exchange of ideas and data as well as hosting a series of Workshops and Special Sessions. IWGoRS created a Web site, backed by an FTP site, for distribution of materials related to rotational seismology. At present, the FTP site contains the 2006 Workshop agenda (also given in the Appendix below) and its PowerPoint presentations, as well as many papers (reasonable-only basis with permission of their authors), a comprehensive citations list, and related information. Eventually, the Web site will become the sole authoritative source for IWGoRS and shared information: http://www.rotational-seismology.org ftp://ehzftp.wr.usgs.gov/jrevans/IWGoRS_FTPsite/ With contributions from various authors during and after the 2006 Workshop, this Report proceeds from the theoretical bases for making rotational measurements (Graizer, Safak, Trifunac) through the available observations (Huang, Lee, Liu, Nigbor), proposed suites of measurements (Hudnut), a discussion of broadband teleseismic rotational

  10. EPOS Seismology services and their users

    Science.gov (United States)

    Haslinger, Florian; Dupont, Aurelien; Michelini, Alberto; Rietbrock, Andreas; Sleeman, Reinoud; Wiemer, Stefan; Basili, Roberto; Bossu, Rémy; Cakti, Eser; Cotton, Fabrice; Crawford, Wayne; Crowley, Helen; Danciu, Laurentiu; Diaz, Jordi; Garth, Tom; Locati, Mario; Luzi, Lucia; Pitilakis, Kyriazis; Roumelioti, Zafeiria; Strollo, Angelo

    2017-04-01

    The construction of seismological community services for the European Plate Observing System Research Infrastructure (EPOS) is by now well under way. A significant number of services are already operational, largely based on those existing at established institutions or collaborations like ORFEUS, EMSC, AHEAD and EFEHR, and more are being added to be ready for internal validation by late 2017. In this presentation we focus on a number of issues related to the interaction of the community of users with the services provided by the seismological part of the EPOS research infrastructure. How users interact with a service (and how satisfied they are with this interaction) is viewed as one important component of the validation of a service within EPOS, and certainly is key to the uptake of a service and from that also it's attributed value. Within EPOS Seismology, the following aspects of user interaction have already surfaced: - user identification (and potential tracking) versus ease-of-access and openness Requesting users to identify themselves when accessing a service provides various advantages to providers and users (e.g. quantifying & qualifying the service use, customization of services and interfaces, handling access rights and quotas), but may impact the ease of access and also shy away users who don't wish to be identified for whatever reason. - service availability versus cost There is a clear and prominent connection between the availability of a service, both regarding uptime and capacity, and its operational cost (IT systems and personnel), and it is often not clear where to draw the line (and based on which considerations). In connection to that, how to best utilize third-party IT infrastructures (either commercial or public), and what the long-term cost implications of that might be, is equally open. - licensing and attribution The issue of intellectual property and associated licensing policies for data, products and services is only recently gaining

  11. EPOS-Seismology: building the Thematic Core Service for Seismology during the EPOS Implementation Phase

    Science.gov (United States)

    Haslinger, Florian; EPOS Seismology Consortium, the

    2015-04-01

    After the successful completion of the EPOS Preparatory Phase, the community of European Research Infrastructures in Seismology is now moving ahead with the build-up of the Thematic Core Service (TCS) for Seismology in EPOS, EPOS-Seismology. Seismology is a domain where European-level infrastructures have been developed since decades, often supported by large-scale EU projects. Today these infrastructures provide services to access earthquake waveforms (ORFEUS), parameters (EMSC) and hazard data and products (EFEHR). The existing organizations constitute the backbone of infrastructures that also in future will continue to manage and host the services of the TCS EPOS-Seismology. While the governance and internal structure of these organizations will remain active, and continue to provide direct interaction with the community, EPOS-Seismology will provide the integration of these within EPOS. The main challenge in the build-up of the TCS EPOS-Seismology is to improve and extend these existing services, producing a single framework which is technically, organizationally and financially integrated with the EPOS architecture, and to further engage various kinds of end users (e.g. scientists, engineers, public managers, citizen scientists). On the technical side the focus lies on four major tasks: - the construction of the next generation software architecture for the European Integrated (waveform) Data Archive EIDA, developing advanced metadata and station information services, fully integrate strong motion waveforms and derived parametric engineering-domain data, and advancing the integration of mobile (temporary) networks and OBS deployments in EIDA; - the further development and expansion of services to access seismological products of scientific interest as provided by the community by implementing a common collection and development (IT) platform, improvements in the earthquake information services e.g. by introducing more robust quality indicators and diversifying

  12. WFCatalog: A catalogue for seismological waveform data

    Science.gov (United States)

    Trani, Luca; Koymans, Mathijs; Atkinson, Malcolm; Sleeman, Reinoud; Filgueira, Rosa

    2017-09-01

    This paper reports advances in seismic waveform description and discovery leading to a new seismological service and presents the key steps in its design, implementation and adoption. This service, named WFCatalog, which stands for waveform catalogue, accommodates features of seismological waveform data. Therefore, it meets the need for seismologists to be able to select waveform data based on seismic waveform features as well as sensor geolocations and temporal specifications. We describe the collaborative design methods and the technical solution showing the central role of seismic feature catalogues in framing the technical and operational delivery of the new service. Also, we provide an overview of the complex environment wherein this endeavour is scoped and the related challenges discussed. As multi-disciplinary, multi-organisational and global collaboration is necessary to address today's challenges, canonical representations can provide a focus for collaboration and conceptual tools for agreeing directions. Such collaborations can be fostered and formalised by rallying intellectual effort into the design of novel scientific catalogues and the services that support them. This work offers an example of the benefits generated by involving cross-disciplinary skills (e.g. data and domain expertise) from the early stages of design, and by sustaining the engagement with the target community throughout the delivery and deployment process.

  13. Vital Signs: Seismology of Icy Ocean Worlds.

    Science.gov (United States)

    Vance, Steven D; Kedar, Sharon; Panning, Mark P; Stähler, Simon C; Bills, Bruce G; Lorenz, Ralph D; Huang, Hsin-Hua; Pike, W T; Castillo, Julie C; Lognonné, Philippe; Tsai, Victor C; Rhoden, Alyssa R

    2018-01-01

    Ice-covered ocean worlds possess diverse energy sources and associated mechanisms that are capable of driving significant seismic activity, but to date no measurements of their seismic activity have been obtained. Such investigations could reveal the transport properties and radial structures, with possibilities for locating and characterizing trapped liquids that may host life and yielding critical constraints on redox fluxes and thus on habitability. Modeling efforts have examined seismic sources from tectonic fracturing and impacts. Here, we describe other possible seismic sources, their associations with science questions constraining habitability, and the feasibility of implementing such investigations. We argue, by analogy with the Moon, that detectable seismic activity should occur frequently on tidally flexed ocean worlds. Their ices fracture more easily than rocks and dissipate more tidal energy than the worlds also should create less thermal noise due to their greater distance and consequently smaller diurnal temperature variations. They also lack substantial atmospheres (except in the case of Titan) that would create additional noise. Thus, seismic experiments could be less complex and less susceptible to noise than prior or planned planetary seismology investigations of the Moon or Mars. Key Words: Seismology-Redox-Ocean worlds-Europa-Ice-Hydrothermal. Astrobiology 18, 37-53.

  14. Understanding and Observing Subglacial Friction Using Seismology

    Science.gov (United States)

    Tsai, V. C.

    2017-12-01

    Glaciology began with a focus on understanding basic mechanical processes and producing physical models that could explain the principal observations. Recently, however, more attention has been paid to the wealth of recent observations, with many modeling efforts relying on data assimilation and empirical scalings, rather than being based on first-principles physics. Notably, ice sheet models commonly assume that subglacial friction is characterized by a "slipperiness" coefficient that is determined by inverting surface velocity observations. Predictions are usually then made by assuming these slipperiness coefficients are spatially and temporally fixed. However, this is only valid if slipperiness is an unchanging material property of the bed and, despite decades of work on subglacial friction, it has remained unclear how to best account for such subglacial physics in ice sheet models. Here, we describe how basic seismological concepts and observations can be used to improve our understanding and determination of subglacial friction. First, we discuss how standard models of granular friction can and should be used in basal friction laws for marine ice sheets, where very low effective pressures exist. We show that under realistic West Antarctic Ice Sheet conditions, standard Coulomb friction should apply in a relatively narrow zone near the grounding line and that this should transition abruptly as one moves inland to a different, perhaps Weertman-style, dependence of subglacial stress on velocity. We show that this subglacial friction law predicts significantly different ice sheet behavior even as compared with other friction laws that include effective pressure. Secondly, we explain how seismological observations of water flow noise and basal icequakes constrain subglacial physics in important ways. Seismically observed water flow noise can provide constraints on water pressures and channel sizes and geometry, leading to important data on subglacial friction

  15. a Collaborative Cyberinfrastructure for Earthquake Seismology

    Science.gov (United States)

    Bossu, R.; Roussel, F.; Mazet-Roux, G.; Lefebvre, S.; Steed, R.

    2013-12-01

    One of the challenges in real time seismology is the prediction of earthquake's impact. It is particularly true for moderate earthquake (around magnitude 6) located close to urbanised areas, where the slightest uncertainty in event location, depth, magnitude estimates, and/or misevaluation of propagation characteristics, site effects and buildings vulnerability can dramatically change impact scenario. The Euro-Med Seismological Centre (EMSC) has developed a cyberinfrastructure to collect observations from eyewitnesses in order to provide in-situ constraints on actual damages. This cyberinfrastructure takes benefit of the natural convergence of earthquake's eyewitnesses on EMSC website (www.emsc-csem.org), the second global earthquake information website within tens of seconds of the occurrence of a felt event. It includes classical crowdsourcing tools such as online questionnaires available in 39 languages, and tools to collect geolocated pics. It also comprises information derived from the real time analysis of the traffic on EMSC website, a method named flashsourcing; In case of a felt earthquake, eyewitnesses reach EMSC website within tens of seconds to find out the cause of the shaking they have just been through. By analysing their geographical origin through their IP address, we automatically detect felt earthquakes and in some cases map the damaged areas through the loss of Internet visitors. We recently implemented a Quake Catcher Network (QCN) server in collaboration with Stanford University and the USGS, to collect ground motion records performed by volunteers and are also involved in a project to detect earthquakes from ground motions sensors from smartphones. Strategies have been developed for several social media (Facebook, Twitter...) not only to distribute earthquake information, but also to engage with the Citizens and optimise data collection. A smartphone application is currently under development. We will present an overview of this

  16. ASDF - A Modern Data Format for Seismology

    Science.gov (United States)

    Krischer, Lion; Smith, James; Lei, Wenjie; Lefebvre, Matthieu; Ruan, Youyi; Sales de Andrade, Elliot; Podhorszki, Norbert; Bozdag, Ebru; Tromp, Jeroen

    2017-04-01

    Seismology as a science is driven by observing and understanding data and it is thus vital to make this as easy and accessible as possible. The growing volume of freely available data coupled with ever expanding computational power enables scientists to take on new and bigger problems. This evolution is to some part hindered as existing data formats have not been designed with it in mind. We present ASDF (http://seismic-data.org), the Adaptable Seismic Data Format, a novel, modern, and especially practical data format for all branches of seismology with particular focus on how it is incorporated into seismic full waveform inversion workflows. The format aims to solve five key issues: Efficiency: Fast I/O operations especially in high performance computing environments, especially limiting the total number of files. Data organization: Different types of data are needed for a variety of tasks. This results in ad hoc data organization and formats that are hard to maintain, integrate, reproduce, and exchange. Data exchange: We want to exchange complex and complete data sets. Reproducibility: Oftentimes just not existing but crucial to advance our science. Mining, visualization, and understanding of data: As data volumes grow, more complex, new techniques to query and visualize large datasets are needed. ASDF tackles these by defining a structure on top of HDF5 reusing as many existing standards (QuakeML, StationXML, PROV) as possible. An essential trait of ASDF is that it empowers the construction of completely self-describing data sets including waveform, station, and event data together with non-waveform data and a provenance description of everything. This for example for the first time enables the proper archival and exchange of processed or synthetic waveforms. To aid community adoption we developed mature tools in Python as well as in C and Fortran. Additionally we provide a formal definition of the format, a validation tool, and integration into widely used

  17. Solving seismological problems using sgraph program: II-waveform modeling

    International Nuclear Information System (INIS)

    Abdelwahed, Mohamed F.

    2012-01-01

    One of the seismological programs to manipulate seismic data is SGRAPH program. It consists of integrated tools to perform advanced seismological techniques. SGRAPH is considered a new system for maintaining and analyze seismic waveform data in a stand-alone Windows-based application that manipulate a wide range of data formats. SGRAPH was described in detail in the first part of this paper. In this part, I discuss the advanced techniques including in the program and its applications in seismology. Because of the numerous tools included in the program, only SGRAPH is sufficient to perform the basic waveform analysis and to solve advanced seismological problems. In the first part of this paper, the application of the source parameters estimation and hypocentral location was given. Here, I discuss SGRAPH waveform modeling tools. This paper exhibits examples of how to apply the SGRAPH tools to perform waveform modeling for estimating the focal mechanism and crustal structure of local earthquakes.

  18. Bringing Seismological Research into the School Setting

    Science.gov (United States)

    Pavlis, G. L.; Hamburger, M. W.

    2004-12-01

    One of the primary goals of educational seismology programs is to bring inquiry-based research to the middle- and high-school classroom setting. Although it is often stated as a long-term goal of science outreach programs, in practice there are many barriers to research in the school setting, among them increasing emphasis on test-oriented training, decreasing interest and participation in science fairs, limited teacher confidence and experience for mentoring research, insufficient student preparedness for research projects, and the short term of university involvement (typically limited to brief one-day encounters). For the past three+ years we have tried to address these issues through a focused outreach program we have called the PEPP Research Fellows Program. This is treated as an honors program in which high school teachers in our group nominate students with interests in science careers. These students are invited to participate in the program, and those who elect to take part participate in a one-day education and training session in the fall. Rather than leave research projects completely open, we direct the students at toward one of two specific, group-oriented projects (in our case, one focusing on local recordings of mining explosions, and a second on teleseismic body-wave analysis), but we encourage them to act as independent researchers and follow topics of interest. The students then work on seismic data from the local educational network or from the IRIS facilities. Following several months of informal interaction with teachers and students (email, web conferencing, etc.), we bring the students and teachers to our university for a weekend research symposium in the spring. Students present their work in oral or poster form and prizes are given for the best papers. Projects range from highly local projects (records of seismic noise at school X) to larger-scale regional projects (analysis of teleseismic P-wave delays at PEPP network stations) From 20 to

  19. Tsunami Ionospheric warning and Ionospheric seismology

    Science.gov (United States)

    Lognonne, Philippe; Rolland, Lucie; Rakoto, Virgile; Coisson, Pierdavide; Occhipinti, Giovanni; Larmat, Carene; Walwer, Damien; Astafyeva, Elvira; Hebert, Helene; Okal, Emile; Makela, Jonathan

    2014-05-01

    The last decade demonstrated that seismic waves and tsunamis are coupled to the ionosphere. Observations of Total Electron Content (TEC) and airglow perturbations of unique quality and amplitude were made during the Tohoku, 2011 giant Japan quake, and observations of much lower tsunamis down to a few cm in sea uplift are now routinely done, including for the Kuril 2006, Samoa 2009, Chili 2010, Haida Gwai 2012 tsunamis. This new branch of seismology is now mature enough to tackle the new challenge associated to the inversion of these data, with either the goal to provide from these data maps or profile of the earth surface vertical displacement (and therefore crucial information for tsunami warning system) or inversion, with ground and ionospheric data set, of the various parameters (atmospheric sound speed, viscosity, collision frequencies) controlling the coupling between the surface, lower atmosphere and the ionosphere. We first present the state of the art in the modeling of the tsunami-atmospheric coupling, including in terms of slight perturbation in the tsunami phase and group velocity and dependance of the coupling strength with local time, ocean depth and season. We then show the confrontation of modelled signals with observations. For tsunami, this is made with the different type of measurement having proven ionospheric tsunami detection over the last 5 years (ground and space GPS, Airglow), while we focus on GPS and GOCE observation for seismic waves. These observation systems allowed to track the propagation of the signal from the ground (with GPS and seismometers) to the neutral atmosphere (with infrasound sensors and GOCE drag measurement) to the ionosphere (with GPS TEC and airglow among other ionospheric sounding techniques). Modelling with different techniques (normal modes, spectral element methods, finite differences) are used and shown. While the fits of the waveform are generally very good, we analyse the differences and draw direction of future

  20. The Albuquerque Seismological Laboratory Data Quality Analyzer

    Science.gov (United States)

    Ringler, A. T.; Hagerty, M.; Holland, J.; Gee, L. S.; Wilson, D.

    2013-12-01

    The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several efforts underway to improve data quality at its stations. The Data Quality Analyzer (DQA) is one such development. The DQA is designed to characterize station data quality in a quantitative and automated manner. Station quality is based on the evaluation of various metrics, such as timing quality, noise levels, sensor coherence, and so on. These metrics are aggregated into a measurable grade for each station. The DQA consists of a website, a metric calculator (Seedscan), and a PostgreSQL database. The website allows the user to make requests for various time periods, review specific networks and stations, adjust weighting of the station's grade, and plot metrics as a function of time. The website dynamically loads all station data from a PostgreSQL database. The database is central to the application; it acts as a hub where metric values and limited station descriptions are stored. Data is stored at the level of one sensor's channel per day. The database is populated by Seedscan. Seedscan reads and processes miniSEED data, to generate metric values. Seedscan, written in Java, compares hashes of metadata and data to detect changes and perform subsequent recalculations. This ensures that the metric values are up to date and accurate. Seedscan can be run in a scheduled task or on demand by way of a config file. It will compute metrics specified in its configuration file. While many metrics are currently in development, some are completed and being actively used. These include: availability, timing quality, gap count, deviation from the New Low Noise Model, deviation from a station's noise baseline, inter-sensor coherence, and data-synthetic fits. In all, 20 metrics are planned, but any number could be added. ASL is actively using the DQA on a daily basis for station diagnostics and evaluation. As Seedscan is scheduled to run every night, data quality analysts are able to then use the

  1. Recent achievements in real-time computational seismology in Taiwan

    Science.gov (United States)

    Lee, S.; Liang, W.; Huang, B.

    2012-12-01

    Real-time computational seismology is currently possible to be achieved which needs highly connection between seismic database and high performance computing. We have developed a real-time moment tensor monitoring system (RMT) by using continuous BATS records and moment tensor inversion (CMT) technique. The real-time online earthquake simulation service is also ready to open for researchers and public earthquake science education (ROS). Combine RMT with ROS, the earthquake report based on computational seismology can provide within 5 minutes after an earthquake occurred (RMT obtains point source information ROS completes a 3D simulation real-time now. For more information, welcome to visit real-time computational seismology earthquake report webpage (RCS).

  2. Vertically Integrated Seismological Analysis II : Inference

    Science.gov (United States)

    Arora, N. S.; Russell, S.; Sudderth, E.

    2009-12-01

    accepting such complex moves need not be hand-designed. Instead, they are automatically determined by the underlying probabilistic model, which is in turn calibrated via historical data and scientific knowledge. Consider a small seismic event which generates weak signals at several different stations, which might independently be mistaken for noise. A birth move may nevertheless hypothesize an event jointly explaining these detections. If the corresponding waveform data then aligns with the seismological knowledge encoded in the probabilistic model, the event may be detected even though no single station observes it unambiguously. Alternatively, if a large outlier reading is produced at a single station, moves which instantiate a corresponding (false) event would be rejected because of the absence of plausible detections at other sensors. More broadly, one of the main advantages of our MCMC approach is its consistent handling of the relative uncertainties in different information sources. By avoiding low-level thresholds, we expect to improve accuracy and robustness. At the conference, we will present results quantitatively validating our approach, using ground-truth associations and locations provided either by simulation or human analysts.

  3. Introduction: seismology and earthquake engineering in Mexico and Central and South America.

    Science.gov (United States)

    Espinosa, A.F.

    1982-01-01

    The results from seismological studies that are used by the engineering community are just one of the benefits obtained from research aimed at mitigating the earthquake hazard. In this issue of Earthquake Information Bulletin current programs in seismology and earthquake engineering, seismic networks, future plans and some of the cooperative programs with different internation organizations are described by Latin-American seismologists. The article describes the development of seismology in Latin America and the seismological interest of the OAS. -P.N.Chroston

  4. Research and development activities of the seismology section for the period January 1986 to December 1987

    International Nuclear Information System (INIS)

    Basu, T.K.; Murty, G.S.

    1988-01-01

    This report sumarises the R and D in Seismology during the period from January 1986 to December 1987. Major topics of current study are (1) Forensic Seismology, (2) Seismicity and Seismic Risk estimates, (3) Reservoir induced seismicity and (4) Rockburst monitoring. Considerable effort is devoted to development of seismic data acquisition systems and theoretical aspects of seismology. (author)

  5. Seismo-Live: Training in Seismology with Jupyter Notebooks

    Science.gov (United States)

    Krischer, Lion; Tape, Carl; Igel, Heiner

    2016-04-01

    Seismological training tends to occur within the isolation of a particular institution with a limited set of tools (codes, libraries) that are often not transferrable outside. Here, we propose to overcome these limitations with a community-driven library of Jupyter notebooks dedicated to training on any aspect of seismology for purposes of education and outreach, on-site or archived tutorials for codes, classroom instruction, and research. A Jupyter notebook (jupyter.org) is an open-source interactive computational environment that allows combining code execution, rich text, mathematics, and plotting. It can be considered a platform that supports reproducible research, as all inputs and outputs may be stored. Text, external graphics, equations can be handled using Markdown (incl. LaTeX) format. Jupyter notebooks are driven by standard web browsers, can be easily exchanged in text format, or converted to other documents (e.g. PDF, slide shows). They provide an ideal format for practical training in seismology. A pilot-platform was setup with a dedicated server such that the Jupyter notebooks can be run in any browser (PC, notepad, smartphone). We show the functionalities of the Seismo-Live platform with examples from computational seismology, seismic data access and processing using the ObsPy library, seismic inverse problems, and others. The current examples are all using the Python programming language but any free language can be used. Potentially, such community platforms could be integrated with the EPOS-IT infrastructure and extended to other fields of Earth sciences.

  6. Rotational Seismology: AGU Session, Working Group, and Website

    Science.gov (United States)

    Lee, William H.K.; Igel, Heiner; Todorovska, Maria I.; Evans, John R.

    2007-01-01

    Introduction Although effects of rotational motions due to earthquakes have long been observed (e. g., Mallet, 1862), nevertheless Richter (1958, p. 213) stated that: 'Perfectly general motion would also involve rotations about three perpendicular axes, and three more instruments for these. Theory indicates, and observation confirms, that such rotations are negligible.' However, Richter provided no references for this claim. Seismology is based primarily on the observation and modeling of three-component translational ground motions. Nevertheless, theoretical seismologists (e.g., Aki and Richards, 1980, 2002) have argued for decades that the rotational part of ground motions should also be recorded. It is well known that standard seismometers are quite sensitive to rotations and therefore subject to rotation-induced errors. The paucity of observations of rotational motions is mainly the result of a lack, until recently, of affordable rotational sensors of sufficient resolution. Nevertheless, in the past decade, a number of authors have reported direct observations of rotational motions and rotations inferred from rigid-body rotations in short baseline accelerometer arrays, creating a burgeoning library of rotational data. For example, ring laser gyros in Germany and New Zealand have led to the first significant and consistent observations of rotational motions from distant earthquakes (Igel et al., 2005, 2007). A monograph on Earthquake Source Asymmetry, Structural Media and Rotation Effects was published recently as well by Teisseyre et al. (2006). Measurement of rotational motions has implications for: (1) recovering the complete ground-displacement history from seismometer recordings; (2) further constraining earthquake rupture properties; (3) extracting information about subsurface properties; and (4) providing additional ground motion information to earthquake engineers for seismic design. A special session on Rotational Motions in Seismology was convened by H

  7. Broad band seismology in the Scotia region. The base Esperanza seismological observatory

    International Nuclear Information System (INIS)

    Russi, M.; Costa, G.; Febrer, J.

    1995-08-01

    The lithospheric study and the identification of relevant lateral heterogeneities in the Antarctic continent and borderlands, is essential to understand the geodynamic evolution both of the continental and oceanic bordering regions. The complexity of the geological evolution and the structural properties of the lithosphere in the Scotia area have been stressed by many authors. The present setting of the area is the result of the mutual interaction among the Antarctic, South American and several minor plants whose geodynamic history and actual boundaries are still partially unknown. The intense seismic activity that characterizes the region encourages the use of the seismological approach to investigate the lithospheric structure of the area. Since January 1992 a broad band three components station is operating at the Antarctic base Esperanza in the NE area of Antarctic Peninsula. The station has been installed with financial support of the Italian Programma Nazionale di Ricerche in Antartide (PNRA) by Osservatorio Geofisico Sperimentale (OGS) and Instituto Antartico Argentino (IAA). Russi et al. (1994) have analyzed selected recordings using the frequency-time analysis (FTAN) method obtaining some relevant information on the large scale structure of the lithosphere in the Scotia region even if data recorded by a single station were available. The extension of our analysis to further events and to horizontal component records is here presented. Within the framework of the international co-operation to the Antarctic Seismographic Network, the OGS and the IAA are upgrading the Esperanza station and installing an additional broad band station near the town of Ushuaia (Tierra del Fuego, Argentina) with the financial support of PNRA. The inversion of the dispersion curves through the FTAN of the signals recorded by an increased number of stations and generated by events with source-station paths spanning the region will allow us to extract the elastic and anelastic

  8. QuakeML - An XML Schema for Seismology

    Science.gov (United States)

    Wyss, A.; Schorlemmer, D.; Maraini, S.; Baer, M.; Wiemer, S.

    2004-12-01

    We propose an extensible format-definition for seismic data (QuakeML). Sharing data and seismic information efficiently is one of the most important issues for research and observational seismology in the future. The eXtensible Markup Language (XML) is playing an increasingly important role in the exchange of a variety of data. Due to its extensible definition capabilities, its wide acceptance and the existing large number of utilities and libraries for XML, a structured representation of various types of seismological data should in our opinion be developed by defining a 'QuakeML' standard. Here we present the QuakeML definitions for parameter databases and further efforts, e.g. a central QuakeML catalog database and a web portal for exchanging codes and stylesheets.

  9. Benefits of rotational ground motions for planetary seismology

    Science.gov (United States)

    Donner, S.; Joshi, R.; Hadziioannou, C.; Nunn, C.; van Driel, M.; Schmelzbach, C.; Wassermann, J. M.; Igel, H.

    2017-12-01

    Exploring the internal structure of planetary objects is fundamental to understand the evolution of our solar system. In contrast to Earth, planetary seismology is hampered by the limited number of stations available, often just a single one. Classic seismology is based on the measurement of three components of translational ground motion. Its methods are mainly developed for a larger number of available stations. Therefore, the application of classical seismological methods to other planets is very limited. Here, we show that the additional measurement of three components of rotational ground motion could substantially improve the situation. From sparse or single station networks measuring translational and rotational ground motions it is possible to obtain additional information on structure and source. This includes direct information on local subsurface seismic velocities, separation of seismic phases, propagation direction of seismic energy, crustal scattering properties, as well as moment tensor source parameters for regional sources. The potential of this methodology will be highlighted through synthetic forward and inverse modeling experiments.

  10. ObsPy: A Python Toolbox for Seismology

    Science.gov (United States)

    Krischer, Lion; Megies, Tobias; Sales de Andrade, Elliott; Barsch, Robert; MacCarthy, Jonathan

    2017-04-01

    In recent years the Python ecosystem evolved into one of the most powerful and productive scientific environments across disciplines. ObsPy (https://www.obspy.org) is a fully community-driven, open-source project dedicated to providing a bridge for seismology into that ecosystem. It does so by offering Read and write support for essentially every commonly used data format in seismology with a unified interface and automatic format detection. This includes waveform data (MiniSEED, SAC, SEG-Y, Reftek, …) as well as station (SEED, StationXML, …) and event meta information (QuakeML, ZMAP, …). Integrated access to the largest data centers, web services, and real-time data streams (FDSNWS, ArcLink, SeedLink, ...). A powerful signal processing toolbox tuned to the specific needs of seismologists. Utility functionality like travel time calculations with the TauP method, geodetic functions, and data visualizations. ObsPy has been in constant development for more than seven years and is developed and used by scientists around the world with successful applications in all branches of seismology. Additionally it nowadays serves as the foundation for a large number of more specialized packages. This presentation will give a short overview of the capabilities of ObsPy and point out several representative or new use cases. Additionally we will discuss the road ahead as well as the long-term sustainability of open-source scientific software.

  11. Trends and opportunities in seismology. [Asilomar, California, January 3--9, 1976

    Energy Technology Data Exchange (ETDEWEB)

    1977-01-01

    Thirty-five experts in the fields of geology, geophysics, and engineering, from academia, government, and industry, were invited to participate in a workshop and address the many problems of national and global concern that require seismological expertise for their solutions. This report reviews the history, accomplishments, and status of seismology; assesses changing trends in seismological research and applications; and recommends future directions in the light of these changes and of the growing needs of society in areas in which seismology can make significant contributions. The first part of the volume discusses areas of opportunity (understanding earthquakes and reducing their hazards; exploration, energy, and resources; understanding the earth and planets) and realizing the benefits (the roles of Federal, state, and local governments, industry, and universities). The second part, Background and Progress, briefly considers each of the following topics: the birth and early growth of seismology, nuclear test monitoring and its scientific ramifications, instrumentation and data processing, geodynamics and plate tectonics, theoretical seismology, structure and composition of the earth, exploration seismology, seismic exploration for minerals, earthquake source mechanism studies, engineering seismology, strong ground motion and related earthquake hazards, volcanoes, tsunamis, planetary seismology, and international aspects of seismology. 26 figures. (RWR)

  12. Large earthquake rates from geologic, geodetic, and seismological perspectives

    Science.gov (United States)

    Jackson, D. D.

    2017-12-01

    Earthquake rate and recurrence information comes primarily from geology, geodesy, and seismology. Geology gives the longest temporal perspective, but it reveals only surface deformation, relatable to earthquakes only with many assumptions. Geodesy is also limited to surface observations, but it detects evidence of the processes leading to earthquakes, again subject to important assumptions. Seismology reveals actual earthquakes, but its history is too short to capture important properties of very large ones. Unfortunately, the ranges of these observation types barely overlap, so that integrating them into a consistent picture adequate to infer future prospects requires a great deal of trust. Perhaps the most important boundary is the temporal one at the beginning of the instrumental seismic era, about a century ago. We have virtually no seismological or geodetic information on large earthquakes before then, and little geological information after. Virtually all-modern forecasts of large earthquakes assume some form of equivalence between tectonic- and seismic moment rates as functions of location, time, and magnitude threshold. That assumption links geology, geodesy, and seismology, but it invokes a host of other assumptions and incurs very significant uncertainties. Questions include temporal behavior of seismic and tectonic moment rates; shape of the earthquake magnitude distribution; upper magnitude limit; scaling between rupture length, width, and displacement; depth dependence of stress coupling; value of crustal rigidity; and relation between faults at depth and their surface fault traces, to name just a few. In this report I'll estimate the quantitative implications for estimating large earthquake rate. Global studies like the GEAR1 project suggest that surface deformation from geology and geodesy best show the geography of very large, rare earthquakes in the long term, while seismological observations of small earthquakes best forecasts moderate earthquakes

  13. Sustainable access to data, products, services and software from the European seismological Research Infrastructures: the EPOS TCS Seismology

    Science.gov (United States)

    Haslinger, Florian; Dupont, Aurelien; Michelini, Alberto; Rietbrock, Andreas; Sleeman, Reinoud; Wiemer, Stefan; Basili, Roberto; Bossu, Rémy; Cakti, Eser; Cotton, Fabrice; Crawford, Wayne; Diaz, Jordi; Garth, Tom; Locati, Mario; Luzi, Lucia; Pinho, Rui; Pitilakis, Kyriazis; Strollo, Angelo

    2016-04-01

    Easy, efficient and comprehensive access to data, data products, scientific services and scientific software is a key ingredient in enabling research at the frontiers of science. Organizing this access across the European Research Infrastructures in the field of seismology, so that it best serves user needs, takes advantage of state-of-the-art ICT solutions, provides cross-domain interoperability, and is organizationally and financially sustainable in the long term, is the core challenge of the implementation phase of the Thematic Core Service (TCS) Seismology within the EPOS-IP project. Building upon the existing European-level infrastructures ORFEUS for seismological waveforms, EMSC for seismological products, and EFEHR for seismological hazard and risk information, and implementing a pilot Computational Earth Science service starting from the results of the VERCE project, the work within the EPOS-IP project focuses on improving and extending the existing services, aligning them with global developments, to at the end produce a well coordinated framework that is technically, organizationally, and financially integrated with the EPOS architecture. This framework needs to respect the roles and responsibilities of the underlying national research infrastructures that are the data owners and main providers of data and products, and allow for active input and feedback from the (scientific) user community. At the same time, it needs to remain flexible enough to cope with unavoidable challenges in the availability of resources and dynamics of contributors. The technical work during the next years is organized in four areas: - constructing the next generation software architecture for the European Integrated (waveform) Data Archive EIDA, developing advanced metadata and station information services, fully integrate strong motion waveforms and derived parametric engineering-domain data, and advancing the integration of mobile (temporary) networks and OBS deployments in

  14. Bringing Seismology's Grand Challenges to the Undergraduate Classroom

    Science.gov (United States)

    Benoit, M. H.; Taber, J.; Hubenthal, M.

    2011-12-01

    The "Seismological Grand Challenges in Understanding Earth's Dynamic Systems," a community-written long-range science plan for the next decade, poses 10 questions to guide fundamental seismological research. Written in an approachable fashion suitable for policymakers, the broad questions and supporting discussion contained in this document offer an ideal framework for the development of undergraduate curricular materials. Leveraging this document, we have created a collection of inquiry-based classroom modules that utilize authentic data to modernize seismological instruction in 100 and 200 level undergraduate courses. The modules not only introduce undergraduates to the broad questions that the seismological community seeks to answer in the future but also showcase the numerous areas where modern seismological research is actively contributing to our understanding of fundamental Earth processes. To date 6 in-depth explorations that correspond to the Grand Challenges document have been developed. The specific topics for each exploration were selected to showcase modern seismological research while also covering topics commonly included in the curriculum of these introductory classes. Examples of activities that have been created and their corresponding Grand Challenge include: -A guided inquiry that introduces students to episodic tremor and slip and compares the GPS and seismic signatures of ETS with those produced from standard tectonic earthquakes (Grand Challenge "How do faults slip?"). - A laboratory exercise where students engage in b-value mapping of volcanic earthquakes to assess potential eruption hazards (How do magmas ascend and erupt?). - A module that introduce students to glacial earthquakes in Greenland and compares their frequency and spatial distribution to tectonic earthquakes (How do processes in the ocean and atmosphere interact with the solid Earth?). What is the relationship between stress and strain in the lithosphere? - An activity that

  15. Thirty Years of Innovation in Seismology with the IRIS Consortium

    Science.gov (United States)

    Sumy, D. F.; Woodward, R.; Aderhold, K.; Ahern, T. K.; Anderson, K. R.; Busby, R.; Detrick, R. S.; Evers, B.; Frassetto, A.; Hafner, K.; Simpson, D. W.; Sweet, J. R.; Taber, J.

    2015-12-01

    The United States academic seismology community, through the National Science Foundation (NSF)-funded Incorporated Research Institutions for Seismology (IRIS) Consortium, has promoted and encouraged a rich environment of innovation and experimentation in areas such as seismic instrumentation, data processing and analysis, teaching and curriculum development, and academic science. As the science continually evolves, IRIS helps drive the market for new research tools that enable science by establishing a variety of standards and goals. This has often involved working directly with manufacturers to better define the technology required, co-funding key development work or early production prototypes, and purchasing initial production runs. IRIS activities have helped establish de-facto international standards and impacted the commercial sector in areas such as seismic instrumentation, open-access data management, and professional development. Key institutional practices, conducted and refined over IRIS' thirty-year history of operations, have focused on open-access data availability, full retention of maximum-bandwidth, continuous data, and direct community access to state-of-the-art seismological instrumentation and software. These practices have helped to cultivate and support a thriving commercial ecosystem, and have been a key element in the professional development of multiple generations of seismologists who now work in both industry and academia. Looking toward the future, IRIS is increasing its engagement with industry to better enable bi-directional exchange of techniques and technology, and enhancing the development of tomorrow's workforce. In this presentation, we will illustrate how IRIS has promoted innovations grown out of the academic community and spurred technological advances in both academia and industry.

  16. Inge Lehmann’s work materials and seismological epistolary archive

    Directory of Open Access Journals (Sweden)

    Erik Hjortenberg

    2009-06-01

    Full Text Available

     

    The Inge Lehmann archive contains thousands of seismological work documents from Inge Lehmann’s private home. For a long time the author thought that the main concern was to keep the documents for posterity. There is now a renewed interest in Inge Lehmann, and some documents were presented in a poster at ESC Potsdam 2004, and the collection of documents were scanned and catalogued 2005-2006 at Storia Geofisica Ambiente in Bologna. Inge Lehmann (1888-1993 is famous for her discovery in 1936 of the earth’s inner core and for work on the upper mantle. A short biography is given. After her retirement in 1953 she worked at home in Denmark, and abroad in USA and in Canada. She took part in the creation of the European Seismological Commission in 1951, and in the creation of the International Seismological Centre in 1964. Inge Lehmann received many awards. Some letters from her early correspondence with Harold Jeffreys are discussed, they show how the inner core was discussed already in 1932. A few of the author’s reminiscences of Inge Lehmann are given.


  17. SEIS-PROV: Practical Provenance for Seismological Data

    Science.gov (United States)

    Krischer, L.; Smith, J. A.; Tromp, J.

    2015-12-01

    It is widely recognized that reproducibility is crucial to advance science, but at the same time it is very hard to actually achieve. This results in it being recognized but also mostly ignored by a large fraction of the community. A key ingredient towards full reproducibility is to capture and describe the history of data, an issue known as provenance. We present SEIS-PROV, a practical format and data model to store provenance information for seismological data. In a seismological context, provenance can be seen as information about the processes that generated and modified a particular piece of data. For synthetic waveforms the provenance information describes which solver and settings therein were used to generate it. When looking at processed seismograms, the provenance conveys information about the different time series analysis steps that led to it. Additional uses include the description of derived data types, such as cross-correlations and adjoint sources, enabling their proper storage and exchange. SEIS-PROV is based on W3C PROV (http://www.w3.org/TR/prov-overview/), a standard for generic provenance information. It then applies an additional set of constraints to make it suitable for seismology. We present a definition of the SEIS-PROV format, a way to check if any given file is a valid SEIS-PROV document, and two sample implementations: One in SPECFEM3D GLOBE (https://geodynamics.org/cig/software/specfem3d_globe/) to store the provenance information of synthetic seismograms and another one as part of the ObsPy (http://obspy.org) framework enabling automatic tracking of provenance information during a series of analysis and transformation stages. This, along with tools to visualize and interpret provenance graphs, offers a description of data history that can be readily tracked, stored, and exchanged.

  18. A Look at the Future of Controlled-Source Seismology

    Science.gov (United States)

    Keller, G. R.; Klemperer, S.; Hole, J.; Snelson, C.

    2008-12-01

    Facilities like EarthScope and IRIS/PASSCAL offer a framework in which to re-assess the role of our highest- resolution geophysical tool, controlled-source seismology. This tool is effective in near surface studies that focus on the upper 100 m of the crust to studies that focus on Moho structure and the lithospheric mantle. IRIS has now existed for over two decades and has transformed the way in which passive-source seismology in particular is carried out. Progress over these two decades has led to major discoveries about continental architecture and evolution through the development of three-dimensional images of the upper mantle and lithosphere. Simultaneously the hydrocarbon exploration industry has mapped increasingly large fractions of our sedimentary basins in three-dimensions and at unprecedented resolution and fidelity. Thanks to the additional instruments in the EarthScope facility, a clear scientific need and opportunity exists to map, at similar resolution, all of the crust - the igneous/metamorphic basement, the non-petroliferous basins that contain the record of continental evolution, and the seismogenic faults and active volcanoes that are the principal natural hazards we face. Controlled-source seismology remains the fundamental technology behind exploration for all fossil fuels and many water resources, and as such is a multi-billion-dollar industry centered in the USA. Academic scientists are leaders in developing the algorithms to process the most advanced industry data, but lack the academic data sets to which to apply this technology. University and government controlled-source seismologists, and their students who will populate the exploration industry, are increasingly divorced from that industry by their reliance on sparse spatial recording of usually only a single-component of the wavefield, generated by even sparser seismic sources. However, if we can find the resources, the technology now exists to provide seismic images of immense

  19. Coronal seismology waves and oscillations in stellar coronae

    CERN Document Server

    Stepanov, Alexander; Nakariakov, Valery M

    2012-01-01

    This concise and systematic account of the current state of this new branch of astrophysics presents the theoretical foundations of plasma astrophysics, magneto-hydrodynamics and coronal magnetic structures, taking into account the full range of available observation techniques -- from radio to gamma. The book discusses stellar loops during flare energy releases, MHD waves and oscillations, plasma instabilities and heating and charged particle acceleration. Current trends and developments in MHD seismology of solar and stellar coronal plasma systems are also covered, while recent p

  20. The experimental operation of a seismological data centre at Blacknest

    International Nuclear Information System (INIS)

    Grover, F.H.

    1978-10-01

    A short account is given of the development and operation of a unit within Blacknest which acts as a centre for handling data received from overseas seismological array stations and stations in the British Isles and also exchanges data with other centres. The work has been carried out as a long-term experiment to assess the capability of small networks of existing research and development stations to participate in the monitoring of a possible future Comprehensive Test Ban treaty (CTB) and to gain experience of the operational requirements for Data Centres. A preliminary assessment of a UK National Technical Means (NTM) for verifying a CTB is obtained inter alia. (author)

  1. seismo-live: Training in Seismology using Jupyter Notebooks

    Science.gov (United States)

    Igel, Heiner; Krischer, Lion; van Driel, Martin; Tape, Carl

    2017-04-01

    Practical training in computational methodologies is still underrepresented in Earth science curriculae despite the increasing use of sometimes highly sophisticated simulation and data processing technologies in research projects. At the same time well-engineered community codes make it easy to return results yet with the danger that the inherent traps of black-box solutions are not well understood. For this purpose we have initiated a community platform (www.seismo-live.org) where Python-based Jupyter notebooks can be accessed and run without necessary downloads or local software installations. The increasingly popular Jupyter notebooks allow combining markup language, graphics, equations, with interactive, executable python codes. The platform already includes general Python training, introduction to the ObsPy library for seismology as well as seismic data processing, noise analysis, and a variety of forward solvers for seismic wave propagation. In addition, an example is shown how Jupyter notebooks can be used to increase reproducibility of published results. Submission of Jupyter notebooks for general seismology are encouraged. The platform can be used for complementary teaching in Earth Science courses on compute-intensive research areas. We present recent developments and new features.

  2. seismo-live: Training in Computational Seismology using Jupyter Notebooks

    Science.gov (United States)

    Igel, H.; Krischer, L.; van Driel, M.; Tape, C.

    2016-12-01

    Practical training in computational methodologies is still underrepresented in Earth science curriculae despite the increasing use of sometimes highly sophisticated simulation technologies in research projects. At the same time well-engineered community codes make it easy to return simulation-based results yet with the danger that the inherent traps of numerical solutions are not well understood. It is our belief that training with highly simplified numerical solutions (here to the equations describing elastic wave propagation) with carefully chosen elementary ingredients of simulation technologies (e.g., finite-differencing, function interpolation, spectral derivatives, numerical integration) could substantially improve this situation. For this purpose we have initiated a community platform (www.seismo-live.org) where Python-based Jupyter notebooks can be accessed and run without and necessary downloads or local software installations. The increasingly popular Jupyter notebooks allow combining markup language, graphics, equations with interactive, executable python codes. We demonstrate the potential with training notebooks for the finite-difference method, pseudospectral methods, finite/spectral element methods, the finite-volume and the discontinuous Galerkin method. The platform already includes general Python training, introduction to the ObsPy library for seismology as well as seismic data processing and noise analysis. Submission of Jupyter notebooks for general seismology are encouraged. The platform can be used for complementary teaching in Earth Science courses on compute-intensive research areas.

  3. Seismologically determined bedload flux during the typhoon season.

    Science.gov (United States)

    Chao, Wei-An; Wu, Yih-Min; Zhao, Li; Tsai, Victor C; Chen, Chi-Hsuan

    2015-02-05

    Continuous seismic records near river channels can be used to quantify the energy induced by river sediment transport. During the 2011 typhoon season, we deployed a seismic array along the Chishan River in the mountain area of southern Taiwan, where there is strong variability in water discharge and high sedimentation rates. We observe hysteresis in the high-frequency (5-15 Hz) seismic noise level relative to the associated hydrological parameters. In addition, our seismic noise analysis reveals an asymmetry and a high coherence in noise cross-correlation functions for several station pairs during the typhoon passage, which corresponds to sediment particles and turbulent flows impacting along the riverbed where the river bends sharply. Based on spectral characteristics of the seismic records, we also detected 20 landslide/debris flow events, which we use to estimate the sediment supply. Comparison of sediment flux between seismologically determined bedload and derived suspended load indicates temporal changes in the sediment flux ratio, which imply a complex transition process from the bedload regime to the suspension regime between typhoon passage and off-typhoon periods. Our study demonstrates the possibility of seismologically monitoring river bedload transport, thus providing valuable additional information for studying fluvial bedrock erosion and mountain landscape evolution.

  4. 10 CFR 72.102 - Geological and seismological characteristics for applications before October 16, 2003 and...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Geological and seismological characteristics for... WASTE Siting Evaluation Factors § 72.102 Geological and seismological characteristics for applications..., sites will be acceptable if the results from onsite foundation and geological investigation, literature...

  5. New developments in high resolution borehole seismology and their applications to reservoir development and management

    Energy Technology Data Exchange (ETDEWEB)

    Paulsson, B.N.P. [Chevron Petroleum Technology Company, La Habra, CA (United States)

    1997-08-01

    Single-well seismology, Reverse Vertical Seismic Profiles (VSP`s) and Crosswell seismology are three new seismic techniques that we jointly refer to as borehole seismology. Borehole seismic techniques are of great interest because they can obtain much higher resolution images of oil and gas reservoirs than what is obtainable with currently used seismic techniques. The quality of oil and gas reservoir management decisions depend on the knowledge of both the large and the fine scale features in the reservoirs. Borehole seismology is capable of mapping reservoirs with an order of magnitude improvement in resolution compared with currently used technology. In borehole seismology we use a high frequency seismic source in an oil or gas well and record the signal in the same well, in other wells, or on the surface of the earth.

  6. Using a Web Site to Support a Seismology Course Textbook

    Science.gov (United States)

    Wysession, M. E.; Stein, S.

    2004-12-01

    We present a course in seismology that consists of a textbook with an accompanying web site (http://epscx.wustl.edu/seismology/book). The web site serves many different functions, and is of great importance as a companion to the curriculum in several different ways: (1) All of the more than 600 figures from the book are available on the web site. Geophysics is a very visually-oriented discipline, and many concepts are more easily taught with appropriate visual tools. In addition, many instructors are now using computer-based lecture programs such as PowerPoint. To aid in this, all of the figures are displayed in a common JPG format, both with and without titles. They are available to be used in a seismology course, or any kind of Earth Science course. This way, an instructor can easily grab a figure from the web site and drop it into a PowerPoint format. The figures are listed by number, but are also obtainable from menus of thumbnail sketches. If an instructor would like all of the figures, they can be obtained as large zip files, which can be unzipped after downloading. In addition, sample PowerPoint lectures using the figures as well the equations from the text will be available on the course web site. (2) Solutions to all of the homework problems are available in PDF format on the course website. Homework is a vital component of any quantitative course, but it is often a significant time commitment for instructors to derive all of the homework problems. In addition, it is much easier to select which homework problems are desired to be assigned if the solutions can be seen. The 64 pages of homework solutions are on a secure web site that requires a user ID and password that can be obtained from the authors. (3) Any errors found in the textbook are immediately posted on an "Errata" web page. Many of these errors are found by instructors who are using the curriculum (and they are given credit for finding the errors!). The text becomes an interactive process

  7. ObsPy - A Python Toolbox for Seismology - and Applications

    Science.gov (United States)

    Krischer, L.; Megies, T.; Barsch, R.; MacCarthy, J.; Lecocq, T.; Koymans, M. R.; Carothers, L.; Eulenfeld, T.; Reyes, C. G.; Falco, N.; Sales de Andrade, E.

    2017-12-01

    Recent years witnessed the evolution of Python's ecosystem into one of the most powerful and productive scientific environments across disciplines. ObsPy (https://www.obspy.org) is a fully community driven, open-source project dedicated to provide a bridge for seismology into that ecosystem. It is a Python toolbox offering: Read and write support for essentially every commonly used data format in seismology with a unified interface and automatic format detection. This includes waveform data (MiniSEED, SAC, SEG-Y, Reftek, …) as well as station (SEED, StationXML, SC3ML, …) and event meta information (QuakeML, ZMAP, …). Integrated access to the largest data centers, web services, and real-time data streams (FDSNWS, ArcLink, SeedLink, ...). A powerful signal processing toolbox tuned to the specific needs of seismologists. Utility functionality like travel time calculations with the TauP method, geodetic functions, and data visualizations. ObsPy has been in constant development for more than eight years and is developed and used by scientists around the world with successful applications in all branches of seismology. Additionally it nowadays serves as the foundation for a large number of more specialized packages. Newest features include: Full interoperability of SEED and StationXML/Inventory objects Access to the Nominal Response Library (NRL) for easy and quick creation of station metadata from scratch Support for the IRIS Federated Catalog Service Improved performance of the EarthWorm client Several improvements to MiniSEED read/write module Improved plotting capabilities for PPSD (spectrograms, PSD of discrete frequencies over time, ..) Support for.. Reading ArcLink Inventory XML Reading Reftek data format Writing SeisComp3 ML (SC3ML) Writing StationTXT format This presentation will give a short overview of the capabilities of ObsPy and point out several representative or new use cases and show-case some projects that are based on ObsPy, e.g.: seismo

  8. Solving some problems of engineering seismology by structural method

    International Nuclear Information System (INIS)

    Ishtev, K.G.; Hadjikov, L.M.; Dineva, P.S.; Jordanov, P.P.

    1983-01-01

    The work suggests a method for solving the direct and inverse problems of the engineer seismology by means of the structural approach of the systems theory. This approach gives a possibility for a simultaneous accounting of the two basic types of damping of the seismic signals in the earth foundation-geometrical damping and a damping in consequence of a dissipative energy loss. By the structural scheme an automatic account is made of the geometric damping of the signals. The damping from a dissipative energy loss on the other hand is accounted for through a choice of the type of frequency characteristics or the transmission functions of the different layers. With a few examples the advantages of the model including the two types of attenuation of the seismic signal are illustrated. An integral coefficient of damping is calculated which analogously to the frequency functions represents a generalized characteristic of is the whole earth foundation. (orig./HP)

  9. Can mobile phones used in strong motion seismology?

    Science.gov (United States)

    D'Alessandro, Antonino; D'Anna, Giuseppe

    2013-04-01

    Micro Electro-Mechanical Systems (MEMS) accelerometers are electromechanical devices able to measure static or dynamic accelerations. In the 1990s MEMS accelerometers revolutionized the automotive-airbag system industry and are currently widely used in laptops, game controllers and mobile phones. Nowadays MEMS accelerometers seems provide adequate sensitivity, noise level and dynamic range to be applicable to earthquake strong motion acquisition. The current use of 3 axes MEMS accelerometers in mobile phone maybe provide a new means to easy increase the number of observations when a strong earthquake occurs. However, before utilize the signals recorded by a mobile phone equipped with a 3 axes MEMS accelerometer for any scientific porpoise, it is fundamental to verify that the signal collected provide reliable records of ground motion. For this reason we have investigated the suitability of the iPhone 5 mobile phone (one of the most popular mobile phone in the world) for strong motion acquisition. It is provided by several MEMS devise like a three-axis gyroscope, a three-axis electronic compass and a the LIS331DLH three-axis accelerometer. The LIS331DLH sensor is a low-cost high performance three axes linear accelerometer, with 16 bit digital output, produced by STMicroelectronics Inc. We have tested the LIS331DLH MEMS accelerometer using a vibrating table and the EpiSensor FBA ES-T as reference sensor. In our experiments the reference sensor was rigidly co-mounted with the LIS331DHL MEMS sensor on the vibrating table. We assessment the MEMS accelerometer in the frequency range 0.2-20 Hz, typical range of interesting in strong motion seismology and earthquake engineering. We generate both constant and damped sine waves with central frequency starting from 0.2 Hz until 20 Hz with step of 0.2 Hz. For each frequency analyzed we generate sine waves with mean amplitude 50, 100, 200, 400, 800 and 1600 mg0. For damped sine waves we generate waveforms with initial amplitude

  10. Moving towards persistent identification in the seismological community

    Science.gov (United States)

    Quinteros, Javier; Evans, Peter; Strollo, Angelo; Ulbricht, Damian; Elger, Kirsten; Bertelmann, Roland

    2016-04-01

    The GEOFON data centre and others in the seismological community have been archiving seismic waveforms for many years. The amount of seismic data available continuously increases due to the use of higher sampling rates and the growing number of stations. In recent years, there is a trend towards standardization of the protocols and formats to improve and homogenise access to these data [FDSN, 2013]. The seismological community has begun assigning a particular persistent identifier (PID), the Digital Object Identifier (DOI), to seismic networks as a first step for properly and consistently attributing the use of data from seismic networks in scientific articles [Evans et al., 2015]. This was codified in a recommendation by the international Federation of Digital Seismic Networks [FDSN, 2014]; DOIs for networks now appear in community web pages. However, our community, in common with other fields of science, still struggles with issues such as: supporting reproducibility of results; providing proper attribution (data citation) for data sets; and measuring the impact (by tracking their use) of, those data sets. Seismological data sets used for research are frequently created "on-the-fly" based on particular user requirements such as location or time period; users prepare requests to select subsets of the data held in seismic networks; the data actually provided may even be held at many different data centres [EIDA, 2016]. These subsets also require careful citation. For persistency, a request must receive exactly the same data when repeated at a later time. However, if data are curated between requests, the data set delivered may differ, severely complicating the ability to reproduce a result. Transmission problems or configuration problems may also inadvertently modify the response to a request. With this in mind, our next step is the assignment of additional EPIC-PIDs to daily data files (currently over 28 million in the GEOFON archive) for use within the data

  11. Towards a single seismological service infrastructure in Europe

    Science.gov (United States)

    Spinuso, A.; Trani, L.; Frobert, L.; Van Eck, T.

    2012-04-01

    In the last five year services and data providers, within the seismological community in Europe, focused their efforts in migrating the way of opening their archives towards a Service Oriented Architecture (SOA). This process tries to follow pragmatically the technological trends and available solutions aiming at effectively improving all the data stewardship activities. These advancements are possible thanks to the cooperation and the follow-ups of several EC infrastructural projects that, by looking at general purpose techniques, combine their developments envisioning a multidisciplinary platform for the earth observation as the final common objective (EPOS, Earth Plate Observation System) One of the first results of this effort is the Earthquake Data Portal (http://www.seismicportal.eu), which provides a collection of tools to discover, visualize and access a variety of seismological data sets like seismic waveform, accelerometric data, earthquake catalogs and parameters. The Portal offers a cohesive distributed search environment, linking data search and access across multiple data providers through interactive web-services, map-based tools and diverse command-line clients. Our work continues under other EU FP7 projects. Here we will address initiatives in two of those projects. The NERA, (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation) project will implement a Common Services Architecture based on OGC services APIs, in order to provide Resource-Oriented common interfaces across the data access and processing services. This will improve interoperability between tools and across projects, enabling the development of higher-level applications that can uniformly access the data and processing services of all participants. This effort will be conducted jointly with the VERCE project (Virtual Earthquake and Seismology Research Community for Europe). VERCE aims to enable seismologists to exploit the wealth of seismic data

  12. Creating a Facebook Page for the Seismological Society of America

    Science.gov (United States)

    Newman, S. B.

    2009-12-01

    In August, 2009 I created a Facebook “fan” page for the Seismological Society of America. We had been exploring cost-effective options for providing forums for two-way communication for some months. We knew that a number of larger technical societies had invested significant sums of money to create customized social networking sites but that a small society would need to use existing low-cost software options. The first thing I discovered when I began to set up the fan page was that an unofficial SSA Facebook group already existed, established by Steven J. Gibbons, a member in Norway. Steven had done an excellent job of posting material about SSA. Partly because of the existing group, the official SSA fan page gained fans rapidly. We began by posting information about our own activities and then added links to activities in the broader geoscience community. While much of this material also appeared on our website and in our publication, Seismological Research Letters (SRL), the tone on the FB page is different. It is less formal with more emphasis on photos and links to other sites, including our own. Fans who are active on FB see the posts as part of their social network and do not need to take the initiative to go to the SSA site. Although the goal was to provide a forum for two-way communication, our initial experience was that people were clearly reading the page but not contributing content. This appears to be case with fan pages of sister geoscience societies. FB offers some demographic information to fan site administrators. In an initial review of the demographics it appeared that fans were younger than the overall demographics of the Society. It appeared that a few of the fans are not members or even scientists. Open questions are: what content will be most useful to fans? How will the existence of the page benefit the membership as a whole? Will the page ultimately encourage two-way communication as hoped? Web 2.0 is generating a series of new

  13. Refining Southern California Geotherms Using Seismologic, Geologic, and Petrologic Constraints

    Science.gov (United States)

    Thatcher, W. R.; Chapman, D. S.; Allam, A. A.; Williams, C. F.

    2017-12-01

    Lithospheric deformation in tectonically active regions depends on the 3D distribution of rheology, which is in turn critically controlled by temperature. Under the auspices of the Southern California Earthquake Center (SCEC) we are developing a 3D Community Thermal Model (CTM) to constrain rheology and so better understand deformation processes within this complex but densely monitored and relatively well-understood region. The San Andreas transform system has sliced southern California into distinct blocks, each with characteristic lithologies, seismic velocities and thermal structures. Guided by the geometry of these blocks we use more than 250 surface heat-flow measurements to define 13 geographically distinct heat flow regions (HFRs). Model geotherms within each HFR are constrained by averages and variances of surface heat flow q0 and the 1D depth distribution of thermal conductivity (k) and radiogenic heat production (A), which are strongly dependent on rock type. Crustal lithologies are not always well known and we turn to seismic imaging for help. We interrogate the SCEC Community Velocity Model (CVM) to determine averages and variances of Vp, Vs and Vp/Vs versus depth within each HFR. We bound (A, k) versus depth by relying on empirical relations between seismic wave speed and rock type and laboratory and modeling methods relating (A, k) to rock type. Many 1D conductive geotherms for each HFR are allowed by the variances in surface heat flow and subsurface (A, k). An additional constraint on the lithosphere temperature field is provided by comparing lithosphere-asthenosphere boundary (LAB) depths identified seismologically with those defined thermally as the depth of onset of partial melting. Receiver function studies in Southern California indicate LAB depths that range from 40 km to 90 km. Shallow LAB depths are correlated with high surface heat flow and deep LAB with low heat flow. The much-restricted families of geotherms that intersect peridotite

  14. Regional geology, tectonic, geomorphology and seismology studies to interest to nuclear power plants at Itaorna beach

    International Nuclear Information System (INIS)

    Hasui, Y.; Almeida, F.F.M. de; Mioto, J.A.; Melo, M.S. de.

    1982-01-01

    The study prepared for the nuclear power plants to be located at Itaorna comprised, the analysis and integration of Geologic, tectonic, geomorphologic and seismologic information and satisfactory results of regional stability were obtained. (L.H.L.L.) [pt

  15. Recent research in earth structure, earthquake and mine seismology, and seismic hazard evaluation in South Africa

    CSIR Research Space (South Africa)

    Wright, C

    2003-07-01

    Full Text Available of earthquakes, earthquake hazard and earth structure in South Africa was prepared for the centennial handbook of the Interna- tional Association of Seismology and the Physics of the Earth?s Interior(IASPEI).3 Referencestothesescompletedinthelastfour...

  16. Mobile and modular. BGR develops seismological monitoring stations for universal applications

    International Nuclear Information System (INIS)

    Hinz, Erwin; Hanneken, Mark

    2016-01-01

    BGR seismologists often set up monitoring stations for testing purposes. The engineers from the Central Seismological Observatory have now developed a new type of mobile monitoring station which can be remotely controlled.

  17. QuakeML: status of the XML-based seismological data exchange format

    OpenAIRE

    Joachim Saul; Philipp Kästli; Fabian Euchner; Danijel Schorlemmer

    2011-01-01

    QuakeML is an XML-based data exchange standard for seismology that is in its fourth year of active community-driven development. Its development was motivated by the need to consolidate existing data formats for applications in statistical seismology, as well as setting a cutting-edge, community-agreed standard to foster interoperability of distributed infrastructures. The current release (version 1.2) is based on a public Request for Comments process and accounts for suggestions and comments...

  18. Urban Seismology: on the origin of earth vibrations within a city

    OpenAIRE

    Díaz, Jordi; Ruiz, Mario; Sánchez-Pastor, Pilar S.; Romero, Paula

    2017-01-01

    Urban seismology has become an active research field in the recent years, both with seismological objectives, as obtaining better microzonation maps in highly populated areas, and with engineering objectives, as the monitoring of traffic or the surveying of historical buildings. We analyze here the seismic records obtained by a broad-band seismic station installed in the ICTJA-CSIC institute, located near the center of Barcelona city. Although this station was installed to introdu...

  19. Research and development activities of the Seismology Section for the period January 1988-December 1989

    International Nuclear Information System (INIS)

    Kumar, Vijay; Murty, G.S.

    1990-01-01

    This report summarises the research and development activities of the Seismology Section during the periods from January 1988 to December 1989. Apart from the ongoing work on forensic seismology, seismicity studies, rock burst monitoring, elastic wave propagation, a new field system became operational at Bhatsa, located about 100 km from Bombay, comprising 11 station radio-telemetered seismic network with a central recording laboratory to study the reservoir induced seismicity. (author). figs., tabs

  20. State-of-the-art of the historical seismology in Colombia

    Directory of Open Access Journals (Sweden)

    E. J. Salcedo Hurtado

    2004-06-01

    Full Text Available In Colombia are available a discreet number of historical seismology investigations, dating back 50 years. This paper reviews basic information about earthquakes studies in Colombia, such as primary sources, compilation of descriptive catalogues and parametric catalogues. Father Jesús Emilio Ramírez made the main systematic study before 1975. During the last 20 years, great earthquakes hit Colombia and, as consequence, historical seismology investigation was developed in the frame of seismic hazard projects.

  1. Effects of magnitude, depth, and time on cellular seismology forecasts

    Science.gov (United States)

    Fisher, Steven Wolf

    This study finds that, in most cases analyzed to date, past seismicity tends to delineate zones where future earthquakes are likely to occur. Network seismicity catalogs for the New Madrid Seismic Zone (NMSZ), Australia (AUS), California (CA), and Alaska (AK) are analyzed using modified versions of the Cellular Seismology (CS) method of Kafka (2002, 2007). The percentage of later occurring earthquakes located near earlier occurring earthquakes typically exceeds the expected percentage for randomly distributed later occurring earthquakes, and the specific percentage is influenced by several variables, including magnitude, depth, time, and tectonic setting. At 33% map area coverage, hit percents are typically 85-95% in the NMSZ, 50-60% in AUS, 75-85% in CA, and 75-85% in AK. Statistical significance testing is performed on trials analyzing the same variables so that the overall regions can be compared, although some tests are inconclusive due to the small number of earthquake sample sizes. These results offer useful insights into understanding the capabilities and limits of CS studies, which can provide guidance for improving the seismicity-based components of seismic hazard assessments.

  2. Ambient seismic noise tomography for exploration seismology at Valhall

    Science.gov (United States)

    de Ridder, S. A.

    2011-12-01

    Permanent ocean-bottom cables installed at the Valhall field can repeatedly record high quality active seismic surveys. But in the absence of active seismic shooting, passive data can be recorded and streamed to the platform in real time. Here I studied 29 hours of data using seismic interferometry. I generate omni-directional Scholte-wave virtual-sources at frequencies considered very-low in the exploration seismology community (0.4-1.75 Hz). Scholte-wave group arrival times are inverted using both eikonal tomography and straight-ray tomography. The top 100 m near-surface at Valhall contains buried channels about 100 m wide that have been imaged with active seismic. Images obtained by ASNT using eikonal tomography or straight-ray tomography both contain anomalies that match these channels. When continuous recordings are made in real-time, tomography images of the shallow subsurface can be formed or updated on a daily basis, forming a very low cost near-surface monitoring system using seismic noise.

  3. Jovian seismology: preliminary results of the SYMPA instrument

    Science.gov (United States)

    Gaulme, P.; Schmider, F. X.; Gay, J.; Jacob, C.; Jeanneaux, F.; Alvarez, M.; Reyes, M.; Valtier, J. C.; Fossat, E.; Palle, P. L.; Belmonte, J. C.; Gelly, B.

    2006-06-01

    Jupiter's internal structure is poorly known (Guillot et al. 2004). Seismology is a powerful tool to investigate the internal structure of planets and stars, by analyzing how acoustic waves propagate. Mosser (1997) and Gudkova & Zarkhov (1999) showed that the detection and the identification of non-radial modes up to degree ℓ=25 can constrain strongly the internal structure. SYMPA is a ground-based network project dedicated to the Jovian oscillations (Schmider et al. 2002). The instrument is composed of a Mach-Zehnder interferometer producing four interferograms of the planetary spectrum. The combination of the four images in phase quadrature allows the reconstruction of the incident light phase, which is related to the Doppler shift generated by the oscillations. Two SYMPA instruments were built at the Nice university and were used simultaneously during two observation campaigns, in 2004 and 2005, at the San Pedro Martir observatory (Mexico) and the Teide observatory (Las Canarias). We will present for the first time the data processing and the preliminary results of the experiment.

  4. Waves and rays in seismology answers to unasked questions

    CERN Document Server

    Slawinski, Michael A

    2016-01-01

    The author dedicates this book to readers who are concerned with finding out the status of concepts, statements and hypotheses, and with clarifying and rearranging them in a logical order. It is thus not intended to teach tools and techniques of the trade, but to discuss the foundations on which seismology — and in a larger sense, the theory of wave propagation in solids — is built. A key question is: why and to what degree can a theory developed for an elastic continuum be used to investigate the propagation of waves in the Earth, which is neither a continuum nor fully elastic. But the scrutiny of the foundations goes much deeper: material symmetry, effective tensors, equivalent media; the influence (or, rather, the lack thereof) of gravitational and thermal effects and the rotation of the Earth, are discussed ab initio. The variational principles of Fermat and Hamilton and their consequences for the propagation of elastic waves, causality, Noether's theorem and its consequences on conservation of energy...

  5. STSHV a teleinformatic system for historic seismology in Venezuela

    Science.gov (United States)

    Choy, J. E.; Palme, C.; Altez, R.; Aranguren, R.; Guada, C.; Silva, J.

    2013-05-01

    From 1997 on, when the first "Jornadas Venezolanas de Sismicidad Historica" took place, a big interest awoke in Venezuela to organize the available information related to historic earthquakes. At that moment only existed one published historic earthquake catalogue, that from Centeno Grau published the first time in 1949. That catalogue had no references about the sources of information. Other catalogues existed but they were internal reports for the petroleum companies and therefore difficult to access. In 2000 Grases et al reedited the Centeno-Grau catalogue, it ended up in a new, very complete catalogue with all the sources well referenced and updated. The next step to organize historic seismicity data was, from 2004 to 2008, the creation of the STSHV (Sistema de teleinformacion de Sismologia Historica Venezolana, http://sismicidad.hacer.ula.ve ). The idea was to bring together all information about destructive historic earthquakes in Venezuela in one place in the internet so it could be accessed easily by a widespread public. There are two ways to access the system. The first one, selecting an earthquake or a list of earthquakes, and the second one, selecting an information source or a list of sources. For each earthquake there is a summary of general information and additional materials: a list with the source parameters published by different authors, a list with intensities assessed by different authors, a list of information sources, a short text summarizing the historic situation at the time of the earthquake and a list of pictures if available. There are searching facilities for the seismic events and dynamic maps can be created. The information sources are classified in: books, handwritten documents, transcription of handwritten documents, documents published in books, journals and congress memories, newspapers, seismologic catalogues and electronic sources. There are facilities to find specific documents or lists of documents with common characteristics

  6. Regional dependence in earthquake early warning and real time seismology

    International Nuclear Information System (INIS)

    Caprio, M.

    2013-01-01

    An effective earthquake prediction method is still a Chimera. What we can do at the moment, after the occurrence of a seismic event, is to provide the maximum available information as soon as possible. This can help in reducing the impact of the quake on population or and better organize the rescue operations in case of post-event actions. This study strives to improve the evaluation of earthquake parameters shortly after the occurrence of a major earthquake, and the characterization of regional dependencies in Real-Time Seismology. The recent earthquake experience from Tohoku (M 9.0, 11.03.2011) showed how an efficient EEW systems can inform numerous people and thus potentially reduce the economic and human losses by distributing warning messages several seconds before the arrival of seismic waves. In the case of devastating earthquakes, usually, in the first minutes to days after the main shock, the common communications channels can be overloaded or broken. In such cases, a precise knowledge of the macroseismic intensity distribution will represent a decisive contribution in help management and in the valuation of losses. In this work, I focused on improving the adaptability of EEW systems (chapters 1 and 2) and in deriving a global relationship for converting peak ground motion into macroseismic intensity and vice versa (chapter 3). For EEW applications, in chapter 1 we present an evolutionary approach for magnitude estimation for earthquake early warning based on real-time inversion of displacement spectra. The Spectrum Inversion (SI) method estimates magnitude and its uncertainty by inferring the shape of the entire displacement spectral curve based on the part of the spectra constrained by available data. Our method can be applied in any region without the need for calibration. SI magnitude and uncertainty estimates are updated each second following the initial P detection and potentially stabilize within 10 seconds from the initial earthquake detection

  7. Regional dependence in earthquake early warning and real time seismology

    Energy Technology Data Exchange (ETDEWEB)

    Caprio, M.

    2013-07-01

    An effective earthquake prediction method is still a Chimera. What we can do at the moment, after the occurrence of a seismic event, is to provide the maximum available information as soon as possible. This can help in reducing the impact of the quake on population or and better organize the rescue operations in case of post-event actions. This study strives to improve the evaluation of earthquake parameters shortly after the occurrence of a major earthquake, and the characterization of regional dependencies in Real-Time Seismology. The recent earthquake experience from Tohoku (M 9.0, 11.03.2011) showed how an efficient EEW systems can inform numerous people and thus potentially reduce the economic and human losses by distributing warning messages several seconds before the arrival of seismic waves. In the case of devastating earthquakes, usually, in the first minutes to days after the main shock, the common communications channels can be overloaded or broken. In such cases, a precise knowledge of the macroseismic intensity distribution will represent a decisive contribution in help management and in the valuation of losses. In this work, I focused on improving the adaptability of EEW systems (chapters 1 and 2) and in deriving a global relationship for converting peak ground motion into macroseismic intensity and vice versa (chapter 3). For EEW applications, in chapter 1 we present an evolutionary approach for magnitude estimation for earthquake early warning based on real-time inversion of displacement spectra. The Spectrum Inversion (SI) method estimates magnitude and its uncertainty by inferring the shape of the entire displacement spectral curve based on the part of the spectra constrained by available data. Our method can be applied in any region without the need for calibration. SI magnitude and uncertainty estimates are updated each second following the initial P detection and potentially stabilize within 10 seconds from the initial earthquake detection

  8. A uniform seismological bulletin for the European - Mediterranean region

    International Nuclear Information System (INIS)

    Bossu, R.; Piedfroid, O.; Riviere, F.

    2002-01-01

    The goal of this EU funded project is to develop means and tools to produce a homogeneous European-Mediterranean seismic bulletin that could serve as a reference. The 3 main objectives are 1) the definition of a unified magnitude scale for M > 3, 2) an improved location of events especially in border regions, 3) Improving rapid and regular data exchange within the European-Mediterranean region. The first step is to define an homogeneous and accurate magnitude estimation for the whole region of interest. Experience shows that the differences in the magnitudes reported by several institutes for a given event may vary up to 1.5 units. Three different magnitude computations are applied on a reference data set of well known events: a Lg waves coda magnitude, a Richter local magnitude and a moment magnitude scale. The comparison of the results is currently carried out. The algorithm associated to the selected magnitude will be implemented locally on a set of stations. New velocity models for border regions are developed from the analysis of the residuals of events recorded by permanent and temporary networks. The robustness and reliability of the 3D models versus 1D model have been evaluated. EMSC gathers via e-mail manually picked seismic phase arrival times with or without associated locations from about 50 seismological institutes of the European- Mediterranean region in a database. These bulletins are automatically merged by unique software. The number of processed events is about 2000 / month and should grow significantly with larger input from Middle East and Northern Africa. Events are then submitted to an automatic analysis of the location reliability, and, for dubious events, to a manual reprocessing. In order to improve data exchange, the installation of autoDRM systems is promoted. (authors)

  9. Monitoring the englacial fracture state using virtual-reflector seismology

    Science.gov (United States)

    Lindner, F.; Weemstra, C.; Walter, F.; Hadziioannou, C.

    2017-12-01

    Fracturing and changes in the englacial macroscopic water content change the elastic bulk properties of ice bodies. Small seismic velocity variations, resulting from such changes, can be measured using a technique called coda-wave interferometry. Here, coda refers to the later-arriving, multiply scattered waves. Often, this technique is applied to so-called virtual-source responses, which can be obtained using seismic interferometry (a simple crosscorrelation process). Compared to other media (e.g., the Earth's crust), however, ice bodies exhibit relatively little scattering. This complicates the application of coda-wave interferometry to the retrieved virtual-source responses. In this work, we therefore investigate the applicability of coda-wave interferometry to virtual-source responses obtained using two alternative seismic interferometric techniques, namely, seismic interferometry by multidimensional deconvolution (SI by MDD), and virtual-reflector seismology (VRS). To that end, we use synthetic data, as well as active-source glacier data acquired on Glacier de la Plaine Morte, Switzerland. Both SI by MDD and VRS allow the retrieval of more accurate virtual-source responses. In particular, the dependence of the retrieved virtual-source responses on the illumination pattern is reduced. We find that this results in more accurate glacial phase-velocity estimates. In addition, VRS introduces virtual reflections from a receiver contour (partly) enclosing the medium of interest. By acting as a sort of virtual reverberation, the coda resulting from the application of VRS significantly increases seismic monitoring capabilities, in particular in cases where natural scattering coda is not available.

  10. Accuracy assessment of high-rate GPS measurements for seismology

    Science.gov (United States)

    Elosegui, P.; Davis, J. L.; Ekström, G.

    2007-12-01

    Analysis of GPS measurements with a controlled laboratory system, built to simulate the ground motions caused by tectonic earthquakes and other transient geophysical signals such as glacial earthquakes, enables us to assess the technique of high-rate GPS. The root-mean-square (rms) position error of this system when undergoing realistic simulated seismic motions is 0.05~mm, with maximum position errors of 0.1~mm, thus providing "ground truth" GPS displacements. We have acquired an extensive set of high-rate GPS measurements while inducing seismic motions on a GPS antenna mounted on this system with a temporal spectrum similar to real seismic events. We found that, for a particular 15-min-long test event, the rms error of the 1-Hz GPS position estimates was 2.5~mm, with maximum position errors of 10~mm, and the error spectrum of the GPS estimates was approximately flicker noise. These results may however represent a best-case scenario since they were obtained over a short (~10~m) baseline, thereby greatly mitigating baseline-dependent errors, and when the number and distribution of satellites on the sky was good. For example, we have determined that the rms error can increase by a factor of 2--3 as the GPS constellation changes throughout the day, with an average value of 3.5~mm for eight identical, hourly-spaced, consecutive test events. The rms error also increases with increasing baseline, as one would expect, with an average rms error for a ~1400~km baseline of 9~mm. We will present an assessment of the accuracy of high-rate GPS based on these measurements, discuss the implications of this study for seismology, and describe new applications in glaciology.

  11. Expanding Horizons in Mitigating Earthquake Related Disasters in Urban Areas: Global Development of Real-Time Seismology

    OpenAIRE

    Utkucu, Murat; Küyük, Hüseyin Serdar; Demir, İsmail Hakkı

    2016-01-01

    Abstract Real-time seismology is a newly developing alternative approach in seismology to mitigate earthquake hazard. It exploits up-to-date advances in seismic instrument technology, data acquisition, digital communications and computer systems for quickly transforming data into earthquake information in real-time to reduce earthquake losses and its impact on social and economic life in the earthquake prone densely populated urban and industrial areas.  Real-time seismology systems are not o...

  12. Provenance for Runtime Workflow Steering and Validation in Computational Seismology

    Science.gov (United States)

    Spinuso, A.; Krischer, L.; Krause, A.; Filgueira, R.; Magnoni, F.; Muraleedharan, V.; David, M.

    2014-12-01

    Provenance systems may be offered by modern workflow engines to collect metadata about the data transformations at runtime. If combined with effective visualisation and monitoring interfaces, these provenance recordings can speed up the validation process of an experiment, suggesting interactive or automated interventions with immediate effects on the lifecycle of a workflow run. For instance, in the field of computational seismology, if we consider research applications performing long lasting cross correlation analysis and high resolution simulations, the immediate notification of logical errors and the rapid access to intermediate results, can produce reactions which foster a more efficient progress of the research. These applications are often executed in secured and sophisticated HPC and HTC infrastructures, highlighting the need for a comprehensive framework that facilitates the extraction of fine grained provenance and the development of provenance aware components, leveraging the scalability characteristics of the adopted workflow engines, whose enactment can be mapped to different technologies (MPI, Storm clusters, etc). This work looks at the adoption of W3C-PROV concepts and data model within a user driven processing and validation framework for seismic data, supporting also computational and data management steering. Validation needs to balance automation with user intervention, considering the scientist as part of the archiving process. Therefore, the provenance data is enriched with community-specific metadata vocabularies and control messages, making an experiment reproducible and its description consistent with the community understandings. Moreover, it can contain user defined terms and annotations. The current implementation of the system is supported by the EU-Funded VERCE (http://verce.eu). It provides, as well as the provenance generation mechanisms, a prototypal browser-based user interface and a web API built on top of a NoSQL storage

  13. Big Data and High-Performance Computing in Global Seismology

    Science.gov (United States)

    Bozdag, Ebru; Lefebvre, Matthieu; Lei, Wenjie; Peter, Daniel; Smith, James; Komatitsch, Dimitri; Tromp, Jeroen

    2014-05-01

    Much of our knowledge of Earth's interior is based on seismic observations and measurements. Adjoint methods provide an efficient way of incorporating 3D full wave propagation in iterative seismic inversions to enhance tomographic images and thus our understanding of processes taking place inside the Earth. Our aim is to take adjoint tomography, which has been successfully applied to regional and continental scale problems, further to image the entire planet. This is one of the extreme imaging challenges in seismology, mainly due to the intense computational requirements and vast amount of high-quality seismic data that can potentially be assimilated. We have started low-resolution inversions (T > 30 s and T > 60 s for body and surface waves, respectively) with a limited data set (253 carefully selected earthquakes and seismic data from permanent and temporary networks) on Oak Ridge National Laboratory's Cray XK7 "Titan" system. Recent improvements in our 3D global wave propagation solvers, such as a GPU version of the SPECFEM3D_GLOBE package, will enable us perform higher-resolution (T > 9 s) and longer duration (~180 m) simulations to take the advantage of high-frequency body waves and major-arc surface waves, thereby improving imbalanced ray coverage as a result of the uneven global distribution of sources and receivers. Our ultimate goal is to use all earthquakes in the global CMT catalogue within the magnitude range of our interest and data from all available seismic networks. To take the full advantage of computational resources, we need a solid framework to manage big data sets during numerical simulations, pre-processing (i.e., data requests and quality checks, processing data, window selection, etc.) and post-processing (i.e., pre-conditioning and smoothing kernels, etc.). We address the bottlenecks in our global seismic workflow, which are mainly coming from heavy I/O traffic during simulations and the pre- and post-processing stages, by defining new data

  14. Twitter Seismology: Earthquake Monitoring and Response in a Social World

    Science.gov (United States)

    Bowden, D. C.; Earle, P. S.; Guy, M.; Smoczyk, G.

    2011-12-01

    The U.S. Geological Survey (USGS) is investigating how the social networking site Twitter, a popular service for sending and receiving short, public, text messages, can augment USGS earthquake response products and the delivery of hazard information. The potential uses of Twitter for earthquake response include broadcasting earthquake alerts, rapidly detecting widely felt events, qualitatively assessing earthquake damage effects, communicating with the public, and participating in post-event collaboration. Several seismic networks and agencies are currently distributing Twitter earthquake alerts including the European-Mediterranean Seismological Centre (@LastQuake), Natural Resources Canada (@CANADAquakes), and the Indonesian meteorological agency (@infogempabmg); the USGS will soon distribute alerts via the @USGSted and @USGSbigquakes Twitter accounts. Beyond broadcasting alerts, the USGS is investigating how to use tweets that originate near the epicenter to detect and characterize shaking events. This is possible because people begin tweeting immediately after feeling an earthquake, and their short narratives and exclamations are available for analysis within 10's of seconds of the origin time. Using five months of tweets that contain the word "earthquake" and its equivalent in other languages, we generate a tweet-frequency time series. The time series clearly shows large peaks correlated with the origin times of widely felt events. To identify possible earthquakes, we use a simple Short-Term-Average / Long-Term-Average algorithm similar to that commonly used to detect seismic phases. As with most auto-detection algorithms, the parameters can be tuned to catch more or less events at the cost of more or less false triggers. When tuned to a moderate sensitivity, the detector found 48 globally-distributed, confirmed seismic events with only 2 false triggers. A space-shuttle landing and "The Great California ShakeOut" caused the false triggers. This number of

  15. Montessus de Ballore, a pioneer of seismology: The man and his work

    Science.gov (United States)

    Cisternas, Armando

    2009-06-01

    Ferdinand de Montessus de Ballore was one of the founders of scientific seismology. He was a pioneer in seismology at the same level as Perrey, Mallet, Milne and Omori. He became familiar with earthquakes and volcanoes in Central America (1881-1885). After his experience in El Salvador his interest for understanding earthquakes and volcanoes oriented all of his life. Back in France he worked out a most complete world catalogue of earthquakes with 170.000 events (1885-1907), and completed his career being the head of the Chilean Seismological Service (1907-1923). Many of his ideas were in advance of later discoveries. He was an exceptional writer and published more than 30 books and hundreds of papers.

  16. ObsPy: A Python toolbox for seismology - Sustainability, New Features, and Applications

    Science.gov (United States)

    Krischer, L.; Megies, T.; Sales de Andrade, E.; Barsch, R.; MacCarthy, J.

    2016-12-01

    ObsPy (https://www.obspy.org) is a community-driven, open-source project dedicated to offer a bridge for seismology into the scientific Python ecosystem. Amongst other things, it provides Read and write support for essentially every commonly used data format in seismology with a unified interface. This includes waveform data as well as station and event meta information. A signal processing toolbox tuned to the specific needs of seismologists. Integrated access to the largest data centers, web services, and databases. Wrappers around third party codes like libmseed and evalresp. Using ObsPy enables users to take advantage of the vast scientific ecosystem that has developed around Python. In contrast to many other programming languages and tools, Python is simple enough to enable an exploratory and interactive coding style desired by many scientists. At the same time it is a full-fledged programming language usable by software engineers to build complex and large programs. This combination makes it very suitable for use in seismology where research code often must be translated to stable and production ready environments, especially in the age of big data. ObsPy has seen constant development for more than six years and enjoys a large rate of adoption in the seismological community with thousands of users. Successful applications include time-dependent and rotational seismology, big data processing, event relocations, and synthetic studies about attenuation kernels and full-waveform inversions to name a few examples. Additionally it sparked the development of several more specialized packages slowly building a modern seismological ecosystem around it. We will present a short overview of the capabilities of ObsPy and point out several representative use cases and more specialized software built around ObsPy. Additionally we will discuss new and upcoming features, as well as the sustainability of open-source scientific software.

  17. 10 CFR 72.103 - Geological and seismological characteristics for applications for dry cask modes of storage on or...

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Geological and seismological characteristics for... § 72.103 Geological and seismological characteristics for applications for dry cask modes of storage on... foundation and geological investigation, literature review, and regional geological reconnaissance show no...

  18. Network of Research Infrastructures for European Seismology (NERIES)—Web Portal Developments for Interactive Access to Earthquake Data on a European Scale

    OpenAIRE

    A. Spinuso; L. Trani; S. Rives; P. Thomy; F. Euchner; Danijel Schorlemmer; Joachim Saul; Andres Heinloo; R. Bossu; T. van Eck

    2009-01-01

    The Network of Research Infrastructures for European Seismology (NERIES) is European Commission (EC) project whose focus is networking together seismological observatories and research institutes into one integrated European infrastructure that provides access to data and data products for research. Seismological institutes and organizations in European and Mediterranean countries maintain large, geographically distributed data archives, therefore this scenario suggested a design approach bas...

  19. Seismology and Research in Schools: One School's Experience

    Science.gov (United States)

    Tedd, Joe; Tedd, Bernie

    2018-01-01

    The UK School Seismology Project started in 2007. King Edward VI High School for Girls was one of the fortunate schools to obtain a school seismometer system, free of charge, as an early adopter of the resource. This report outlines our experiences with the system over the past 10 years and describes our recent research on the relationship between…

  20. The establishment of the Blacknest seismological database on the Rutherford Laboratory system 360/195 computer

    International Nuclear Information System (INIS)

    Blamey, C.

    1977-01-01

    In order to assess the problems which might arise from monitoring a comprehensive test ban treaty by seismological methods, an experimental monitoring operation is being conducted. This work has involved the establishment of a database on the Rutherford Laboratory 360/195 system computer. The database can be accessed in the UK over the public telephone network and in the USA via ARPANET. (author)

  1. Solving seismological problems using SGRAPH program: I-source parameters and hypocentral location

    International Nuclear Information System (INIS)

    Abdelwahed, Mohamed F.

    2012-01-01

    SGRAPH program is considered one of the seismological programs that maintain seismic data. SGRAPH is considered unique for being able to read a wide range of data formats and manipulate complementary tools in different seismological subjects in a stand-alone Windows-based application. SGRAPH efficiently performs the basic waveform analysis and solves advanced seismological problems. The graphical user interface (GUI) utilities and the Windows facilities such as, dialog boxes, menus, and toolbars simplified the user interaction with data. SGRAPH supported the common data formats like, SAC, SEED, GSE, ASCII, and Nanometrics Y-format, and others. It provides the facilities to solve many seismological problems with the built-in inversion and modeling tools. In this paper, I discuss some of the inversion tools built-in SGRAPH related to source parameters and hypocentral location estimation. Firstly, a description of the SGRAPH program is given discussing some of its features. Secondly, the inversion tools are applied to some selected events of the Dahshour earthquakes as an example of estimating the spectral and source parameters of local earthquakes. In addition, the hypocentral location of these events are estimated using the Hypoinverse 2000 program operated by SGRAPH.

  2. Jupyter Notebooks for Earth Sciences: An Interactive Training Platform for Seismology

    Science.gov (United States)

    Igel, H.; Chow, B.; Donner, S.; Krischer, L.; van Driel, M.; Tape, C.

    2017-12-01

    We have initiated a community platform (http://www.seismo-live.org) where Python-based Jupyter notebooks (https://jupyter.org) can be accessed and run without necessary downloads or local software installations. The increasingly popular Jupyter notebooks allow the combination of markup language, graphics, and equations with interactive, executable Python code examples. Jupyter notebooks are a powerful and easy-to-grasp tool for students to develop entire projects, scientists to collaborate and efficiently interchange evolving workflows, and trainers to develop efficient practical material. Utilizing the tmpnb project (https://github.com/jupyter/tmpnb), we link the power of Jupyter notebooks with an underlying server, such that notebooks can be run from anywhere, even on smart phones. We demonstrate the potential with notebooks for 1) learning the programming language Python, 2) basic signal processing, 3) an introduction to the ObsPy library (https://obspy.org) for seismology, 4) seismic noise analysis, 5) an entire suite of notebooks for computational seismology (the finite-difference method, pseudospectral methods, finite/spectral element methods, the finite-volume and the discontinuous Galerkin methods, Instaseis), 6) rotational seismology, 7) making results in papers fully reproducible, 8) a rate-and-state friction toolkit, 9) glacial seismology. The platform is run as a community project using Github. Submission of complementary Jupyter notebooks is encouraged. Extension in the near future include linear(-ized) and nonlinear inverse problems.

  3. The EGU Seismology Division Early Career Scientist Representative team and its initiatives

    Science.gov (United States)

    Parisi, Laura; Ermert, Laura; Gualtieri, Lucia; Spieker, Kathrin; Van Noten, Koen; Agius, Matthew R.; Mai, P. Martin

    2017-04-01

    Since 2014, the Seismology Division (SM) of the European Geosciences Union (EGU) has its Early Career Scientist (ECS) representative to reach out to its numerous 'younger' members. In April 2016, a new team of representatives joined the Division. We are a vivid team of early career scientists, representing both (either) PhD students and post-doctoral researchers working in different seismological disciplines and different countries. The initiatives of the SM ECS-rep team have various aims: (1) to motivate the ECSs to get involved in activities and initiatives of the EGU and the Seismology Division, (2) to promote the research of ECSs, (3) to discuss issues concerning seismologists during this particular stage of their career, (4) to share ideas on how to promote equality between scientists and (5) to improve on the public dissemination of scientific knowledge. In an effort to reach out to experienced and ECS seismologists more effectively and to continuously encourage to voice their ideas by contributing and following our initiatives, a blog and social media pages dedicated to seismology and earthquake trivia are run by the team. Weekly posts are published on the blog and shared on the social media regarding scientific and social aspects of seismology. One of the major contributions recently introduced to the blog is the "Paper of the Month" series where experienced seismologists write about recent or classical - must read - seismology articles. We also aim to organise and promote social and scientific events. During the EGU General Assembly 2016 a social event was held in Vienna allowing ECS to network with peers in an informal environment. Given the success of this event, a similar event will be organized during the General Assembly 2017. Also, similar to previous years, a short course on basic seismology for non seismologists will be requested and offered to all ECSs attending the General Assembly. Finally, a workshop dedicated entirely to ECSs seismologists

  4. SGRAPH (SeismoGRAPHer): Seismic waveform analysis and integrated tools in seismology

    Science.gov (United States)

    Abdelwahed, Mohamed F.

    2012-03-01

    Although numerous seismological programs are currently available, most of them suffer from the inability to manipulate different data formats and the lack of embedded seismological tools. SeismoGRAPHer, or simply SGRAPH, is a new system for maintaining and analyzing seismic waveform data in a stand-alone, Windows-based application that manipulates a wide range of data formats. SGRAPH was intended to be a tool sufficient for performing basic waveform analysis and solving advanced seismological problems. The graphical user interface (GUI) utilities and the Windows functionalities, such as dialog boxes, menus, and toolbars, simplify the user interaction with the data. SGRAPH supports common data formats, such as SAC, SEED, GSE, ASCII, and Nanometrics Y-format, and provides the ability to solve many seismological problems with built-in inversion tools. Loaded traces are maintained, processed, plotted, and saved as SAC, ASCII, or PS (post script) file formats. SGRAPH includes Generalized Ray Theory (GRT), genetic algorithm (GA), least-square fitting, auto-picking, fast Fourier transforms (FFT), and many additional tools. This program provides rapid estimation of earthquake source parameters, location, attenuation, and focal mechanisms. Advanced waveform modeling techniques are provided for crustal structure and focal mechanism estimation. SGRAPH has been employed in the Egyptian National Seismic Network (ENSN) as a tool assisting with routine work and data analysis. More than 30 users have been using previous versions of SGRAPH in their research for more than 3 years. The main features of this application are ease of use, speed, small disk space requirements, and the absence of third-party developed components. Because of its architectural structure, SGRAPH can be interfaced with newly developed methods or applications in seismology. A complete setup file, including the SGRAPH package with the online user guide, is available.

  5. Promoting seismology education and research via the IRIS Education and Public Outreach Program

    Science.gov (United States)

    Taber, J. J.; Bravo, T. K.; Dorr, P. M.; Hubenthal, M.; Johnson, J. A.; McQuillan, P.; Sumy, D. F.; Welti, R.

    2015-12-01

    The Incorporated Research Institutions for Seismology's Education and Public Outreach (EPO) program is committed to advancing awareness and understanding of seismology and geophysics, while inspiring careers in the Earth sciences. To achieve this mission, IRIS EPO combines content and research expertise of consortium membership with educational and outreach expertise of IRIS staff to create a portfolio of programs, products, and services that target a range of audiences, including grades 6-12 students and teachers, undergraduate and graduate students, faculty, and the general public. IRIS also partners with UNAVCO and other organizations in support of EarthScope where the facilities are well-suited for sustained engagement of multiple audiences. Examples of research-related EPO products and services include the following resources. Tools developed in collaboration with IRIS Data Services provide public and educational access to data, and to a suite of data products. Teachers can stream seismic data from educational or research sensors into their classroom, and the Active Earth Monitor display, designed for visitor centers, universities and small museums, provides views of recent data along with animations that explain seismology concepts, and stories about recent research. Teachable Moment slide sets, created in collaboration with the University of Portland within 24 hours of major earthquakes, provide interpreted USGS tectonic maps and summaries, animations, visualizations, and other event-specific information so educators can explore newsworthy earthquakes with their students. Intro undergraduate classroom activities have been designed to introduce students to some grand challenges in seismological research, while our Research Experiences for Undergraduates program pairs students with seismology researchers throughout the Consortium and provides the opportunity for the students to present their research at a national meeting. EPO activities are evaluated via a

  6. Recent activities of the Seismology Division Early Career Representative(s)

    Science.gov (United States)

    Agius, Matthew; Van Noten, Koen; Ermert, Laura; Mai, P. Martin; Krawczyk, CharLotte

    2016-04-01

    The European Geosciences Union is a bottom-up-organisation, in which its members are represented by their respective scientific divisions, committees and council. In recent years, EGU has embarked on a mission to reach out for its numerous 'younger' members by giving awards to outstanding young scientists and the setting up of Early Career Scientists (ECS) representatives. The division representative's role is to engage in discussions that concern students and early career scientists. Several meetings between all the division representatives are held throughout the year to discuss ideas and Union-wide issues. One important impact ECS representatives have had on EGU is the increased number of short courses and workshops run by ECS during the annual General Assembly. Another important contribution of ECS representatives was redefining 'Young Scientist' to 'Early Career Scientist', which avoids discrimination due to age. Since 2014, the Seismology Division has its own ECS representative. In an effort to more effectively reach out for young seismologists, a blog and a social media page dedicated to seismology have been set up online. With this dedicated blog, we'd like to give more depth to the average browsing experience by enabling young researchers to explore various seismology topics in one place while making the field more exciting and accessible to the broader community. These pages are used to promote the latest research especially of young seismologists and to share interesting seismo-news. Over the months the pages proved to be popular, with hundreds of views every week and an increased number of followers. An online survey was conducted to learn more about the activities and needs of early career seismologists. We present the results from this survey, and the work that has been carried out over the last two years, including detail of what has been achieved so far, and what we would like the ECS representation for Seismology to achieve. Young seismologists are

  7. Mobile and modular. BGR develops seismological monitoring stations for universal applications; Mobil und modular. BGR entwickelt universell einsetzbare seismologische Messstationen

    Energy Technology Data Exchange (ETDEWEB)

    Hinz, Erwin; Hanneken, Mark [Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany). Fachbereich ' ' Seismologisches Zentralobservatorium, Kernwaffenteststopp' '

    2016-05-15

    BGR seismologists often set up monitoring stations for testing purposes. The engineers from the Central Seismological Observatory have now developed a new type of mobile monitoring station which can be remotely controlled.

  8. Study of seismological evasion. Part III. Evaluation of evasion possibilities using codas of large earthquakes

    International Nuclear Information System (INIS)

    Evernden, J.F.

    1976-01-01

    The seismological aspects of various proposed means of obscuring or hiding the seismic signatures of explosions from a surveillance network are discussed. These so-called evasion schemes are discussed from the points of view of both the evader and the monitor. The analysis will be conducted in terms of the USSR solely because that country is so vast and the geological/geophysical complexities of the country are so great that the complete spectrum of hypothesized evasion schemes requires discussion. Techniques appropriate for use when the seismic noise problem is interference due to codas of P and surface waves from earthquakes are described, and the capabilities of several seismological networks to restrain use of such codas for effective evasion are analyzed

  9. Research and development activities of the Seismology Section for the period January 1984 - December 1985

    International Nuclear Information System (INIS)

    Krishnan, C.A.; Murty, G.S.

    1987-01-01

    The Research and Development (R and D) activities during 1984-1985 of the Seismology Section of the Bhabha Atomic Research Centre, Bombay are reported in the form of individual summaries. The R and D activities of the Section are directed towards development of seismological instruments and methods of analysis of the seismic field data with the main objective of detecting underground nuclear explosions and assessing seismicity and seismic risk of sites considered for nuclear power stations. The Section has two field stations - one at Gauribidanur in the Southern part of the country and another at Delhi i.e. in the northern part of the country. During the report period, a total of 62 events out of the detected ones were identified as underground explosions. The expertise of the Section is also made available for outside organisations. (M.G.B.)

  10. Seismology, 1983, nuclear test ban verification earthquake and earth resource investigation

    Energy Technology Data Exchange (ETDEWEB)

    1984-03-01

    This progress report for 1983 is the fourth yearly report summarizing the activities of the Division of Applied Seismology of the National Defence Research Institute (FOA) in Sweden. This division of the Institute is mainly involved in seismic discrimination and nuclear explosion monitoring. Special attention is paid in this report to the development of International Data Centers as a component of a global monitoring system. The division is also conducting a project on seismic risk estimation at nuclear power plants in Sweden. This project includes operating a network of local seismic stations in Sweden. Two seismic exploration projects are also currently being conducted. One project involves the further development of seismic methods for oil exploration, and the other the investigation of crystalline rock using seismic cross hole measurement. Finally the Division of Applied Seismology is conducting a project where seismic sensor in military applications are studied.

  11. Seismology: Ways and means for regional cooperation. Transparencies used during the presentation

    International Nuclear Information System (INIS)

    Menzhi, M.

    1999-01-01

    Within the frame of international cooperation in the field of CTBT, this paper describes the first seismologic station established in Morocco in 1934, and in sixties and seventies another 15 stations after the earthquake in Agadir. In 1982, a system for seismic detection was installed having as main objectives he following: coordination and correlation of activities concerned with evaluation of seismic risks in the Mediterranean region, and integration of geophysical data needed for seismic risk assessment

  12. Reflections from the interface between seismological research and earthquake risk reduction

    Science.gov (United States)

    Sargeant, S.

    2012-04-01

    Scientific understanding of earthquakes and their attendant hazards is vital for the development of effective earthquake risk reduction strategies. Within the global disaster reduction policy framework (the Hyogo Framework for Action, overseen by the UN International Strategy for Disaster Reduction), the anticipated role of science and scientists is clear, with respect to risk assessment, loss estimation, space-based observation, early warning and forecasting. The importance of information sharing and cooperation, cross-disciplinary networks and developing technical and institutional capacity for effective disaster management is also highlighted. In practice, the degree to which seismological information is successfully delivered to and applied by individuals, groups or organisations working to manage or reduce the risk from earthquakes is variable. The challenge for scientists is to provide fit-for-purpose information that can be integrated simply into decision-making and risk reduction activities at all levels of governance and at different geographic scales, often by a non-technical audience (i.e. people without any seismological/earthquake engineering training). The interface between seismological research and earthquake risk reduction (defined here in terms of both the relationship between the science and its application, and the scientist and other risk stakeholders) is complex. This complexity is a function of a range issues that arise relating to communication, multidisciplinary working, politics, organisational practices, inter-organisational collaboration, working practices, sectoral cultures, individual and organisational values, worldviews and expectations. These factors can present significant obstacles to scientific information being incorporated into the decision-making process. The purpose of this paper is to present some personal reflections on the nature of the interface between the worlds of seismological research and risk reduction, and the

  13. SeisCode: A seismological software repository for discovery and collaboration

    Science.gov (United States)

    Trabant, C.; Reyes, C. G.; Clark, A.; Karstens, R.

    2012-12-01

    SeisCode is a community repository for software used in seismological and related fields. The repository is intended to increase discoverability of such software and to provide a long-term home for software projects. Other places exist where seismological software may be found, but none meet the requirements necessary for an always current, easy to search, well documented, and citable resource for projects. Organizations such as IRIS, ORFEUS, and the USGS have websites with lists of available or contributed seismological software. Since the authors themselves do often not maintain these lists, the documentation often consists of a sentence or paragraph, and the available software may be outdated. Repositories such as GoogleCode and SourceForge, which are directly maintained by the authors, provide version control and issue tracking but do not provide a unified way of locating geophysical software scattered in and among countless unrelated projects. Additionally, projects are hosted at language-specific sites such as Mathworks and PyPI, in FTP directories, and in websites strewn across the Web. Search engines are only partially effective discovery tools, as the desired software is often hidden deep within the results. SeisCode provides software authors a place to present their software, codes, scripts, tutorials, and examples to the seismological community. Authors can choose their own level of involvement. At one end of the spectrum, the author might simply create a web page that points to an existing site. At the other extreme, an author may choose to leverage the many tools provided by SeisCode, such as a source code management tool with integrated issue tracking, forums, news feeds, downloads, wikis, and more. For software development projects with multiple authors, SeisCode can also be used as a central site for collaboration. SeisCode provides the community with an easy way to discover software, while providing authors a way to build a community around their

  14. The art of communicating seismology to broad audiences: the exhibition which changed the perception

    Science.gov (United States)

    Toma-Danila, Dragos; Tataru, Dragos; Nastase, Eduard; Muntean, Alexandra; Partheniu, Raluca

    2017-04-01

    Seismology is a geoscience often perceived by uninstructed broad audiences as unreliable or inconsistent, since it cannot predict future earthquakes or warn about them effectively; this criticism disregards important achievements that seismology has offered during its more than 100 years of history - such as evidence of Earth's inner structure, knowledge regarding plate tectonics, mineral resource identification, contributions to risk mitigation, monitoring of explosions etc. Moreover, seismology is a field of study with significant advances, which make (or could make) living much safer, in areas with high seismic hazard. We mentioned "could make" since people often fail to understand an important aspect: seismology offers consistent knowledge regarding how to prepare, construct or behave - but it's up to people and authorities to implement the effective measures. In all this story, the effective communication between scientists and the general public plays a major role, making the leap from misconception to relevant impact. As scientists, we wanted to show the true meaning and purpose of seismology to all categories of people. We are in the final stage of the MOBEE (MOBile Earthquake Exhibition) Project implementation, an innovative initiative in a highly seismic country (Romania), where major Vrancea intermediate-depth earthquakes source have the potential to generate a significant amount of damage over large areas; however, unlike countries like Japan, the medium to long period between felt or significant events (20-40 years) is long enough to make the newer generation in Romania disregardful of the hazard, and older generations skeptical about the role of seismology. MOBEE intended to freshen up things, raise awareness and change the overall perception - through new approaches involving a blend of digital content (interactive apps, responsive and continuously updated website), 3D models achieved through new technologies (3D printing, fiber optics), non

  15. Facilitating open global data use in earthquake source modelling to improve geodetic and seismological approaches

    Science.gov (United States)

    Sudhaus, Henriette; Heimann, Sebastian; Steinberg, Andreas; Isken, Marius; Vasyura-Bathke, Hannes

    2017-04-01

    In the last few years impressive achievements have been made in improving inferences about earthquake sources by using InSAR (Interferometric Synthetic Aperture Radar) data. Several factors aided these developments. The open data basis of earthquake observations has expanded vastly with the two powerful Sentinel-1 SAR sensors up in space. Increasing computer power allows processing of large data sets for more detailed source models. Moreover, data inversion approaches for earthquake source inferences are becoming more advanced. By now data error propagation is widely implemented and the estimation of model uncertainties is a regular feature of reported optimum earthquake source models. Also, more regularly InSAR-derived surface displacements and seismological waveforms are combined, which requires finite rupture models instead of point-source approximations and layered medium models instead of homogeneous half-spaces. In other words the disciplinary differences in geodetic and seismological earthquake source modelling shrink towards common source-medium descriptions and a source near-field/far-field data point of view. We explore and facilitate the combination of InSAR-derived near-field static surface displacement maps and dynamic far-field seismological waveform data for global earthquake source inferences. We join in the community efforts with the particular goal to improve crustal earthquake source inferences in generally not well instrumented areas, where often only the global backbone observations of earthquakes are available provided by seismological broadband sensor networks and, since recently, by Sentinel-1 SAR acquisitions. We present our work on modelling standards for the combination of static and dynamic surface displacements in the source's near-field and far-field, e.g. on data and prediction error estimations as well as model uncertainty estimation. Rectangular dislocations and moment-tensor point sources are exchanged by simple planar finite

  16. COST Action ES1401 TIDES: a European network on TIme DEpendent Seismology

    Science.gov (United States)

    Morelli, Andrea

    2016-04-01

    Using the full-length records of seismic events and background ambient noise, today seismology is going beyond still-life snapshots of the interior of the Earth, and look into time-dependent changes of its properties. Data availability has grown dramatically with the expansion of seismographic networks and data centers, so as to enable much more detailed and accurate analyses. COST Action ES1401 TIDES (TIme DEpendent Seismology; http://tides-cost.eu) aims at structuring the EU seismological community to enable development of data-intensive, time-dependent techniques for monitoring Earth active processes (e.g., earthquakes, volcanic eruptions, landslides, glacial earthquakes) as well as oil/gas reservoirs. The main structure of TIDES is organised around working groups on: Workflow integration of data and computing resources; Seismic interferometry and ambient noise; Forward problems and High-performance computing applications; Seismic tomography, full waveform inversion and uncertainties; Applications in the natural environment and industry. TIDES is an open network of European laboratories with complementary skills, and is organising a series of events - workshops and advanced training schools - as well as supporting short-duration scientific stays. The first advanced training school was held in Bertinoro (Italy) on June 2015, with attendance of about 100 participants from 20 European countries, was devoted to how to manage and model seismic data with modern tools. The next school, devoted to ambient noise, will be held in 2016 Portugal: the program will be announced at the time of this conference. TIDES will strengthen Europe's role in a critical field for natural hazards and natural resource management.

  17. How citizen seismology is transforming rapid public earthquake information and interactions between seismologists and society

    Science.gov (United States)

    Bossu, Rémy; Steed, Robert; Mazet-Roux, Gilles; Roussel, Fréderic; Caroline, Etivant

    2015-04-01

    Historical earthquakes are only known to us through written recollections and so seismologists have a long experience of interpreting the reports of eyewitnesses, explaining probably why seismology has been a pioneer in crowdsourcing and citizen science. Today, Internet has been transforming this situation; It can be considered as the digital nervous system comprising of digital veins and intertwined sensors that capture the pulse of our planet in near real-time. How can both seismology and public could benefit from this new monitoring system? This paper will present the strategy implemented at Euro-Mediterranean Seismological Centre (EMSC) to leverage this new nervous system to detect and diagnose the impact of earthquakes within minutes rather than hours and how it transformed information systems and interactions with the public. We will show how social network monitoring and flashcrowds (massive website traffic increases on EMSC website) are used to automatically detect felt earthquakes before seismic detections, how damaged areas can me mapped through concomitant loss of Internet sessions (visitors being disconnected) and the benefit of collecting felt reports and geolocated pictures to further constrain rapid impact assessment of global earthquakes. We will also describe how public expectations within tens of seconds of ground shaking are at the basis of improved diversified information tools which integrate this user generated contents. A special attention will be given to LastQuake, the most complex and sophisticated Twitter QuakeBot, smartphone application and browser add-on, which deals with the only earthquakes that matter for the public: the felt and damaging earthquakes. In conclusion we will demonstrate that eyewitnesses are today real time earthquake sensors and active actors of rapid earthquake information.

  18. Developing Federated Services within Seismology: IRIS' involvement in the CoopEUS Project

    Science.gov (United States)

    Ahern, T. K.; Trabant, C. M.; Stults, M.

    2014-12-01

    As a founding member of the CoopEUS initiative, IRIS Data Services has partnered with five data centers in Europe and the UC Berkeley (NCEDC) in the US to implement internationally standardized web services to access seismological data using identical methodologies. The International Federation of Digital Seismograph Networks (FDSN) holds commission status within IASPEI/IUGG and as such is the international body that governs data exchange formats and access protocols within seismology. The CoopEUS project involves IRIS and UNAVCO as part of the EarthScope project and the European collaborators are all members of the European Plate Observing System (EPOS). CoopEUS includes one work package that attempts to coordinate data access between EarthScope and EPOS facilities. IRIS has worked with its partners in the FDSN to develop and adopt three key international service standards within seismology. These include 1) fdsn-dataselect, a service that returns time series data in a variety of standard formats, 2) fdsn-station, a service that returns related metadata about a seismic station in stationXML format, and 3) fdsn-event, a service that returns information about earthquakes and other seismic events in QuakeML format. Currently the 5 European data centers supporting these services include the ORFEUS Data Centre in the Netherlands, the GFZ German Research Centre for Geosciences in Potsdam, Germany, ETH Zurich in Switzerland, INGV in Rome, Italy, and the RESIF Data Centre in Grenoble France. Presently these seven centres can all be accessed using standardized web services with identical service calls and returns results in standardized ways. IRIS is developing an IRIS federator that will allow a client to seamlessly access information across the federated centers. Details and current status of the IRIS Federator will be presented.

  19. QuakeML: XML for Seismological Data Exchange and Resource Metadata Description

    Science.gov (United States)

    Euchner, F.; Schorlemmer, D.; Becker, J.; Heinloo, A.; Kästli, P.; Saul, J.; Weber, B.; QuakeML Working Group

    2007-12-01

    QuakeML is an XML-based data exchange format for seismology that is under development. Current collaborators are from ETH, GFZ, USC, USGS, IRIS DMC, EMSC, ORFEUS, and ISTI. QuakeML development was motivated by the lack of a widely accepted and well-documented data format that is applicable to a broad range of fields in seismology. The development team brings together expertise from communities dealing with analysis and creation of earthquake catalogs, distribution of seismic bulletins, and real-time processing of seismic data. Efforts to merge QuakeML with existing XML dialects are under way. The first release of QuakeML will cover a basic description of seismic events including picks, arrivals, amplitudes, magnitudes, origins, focal mechanisms, and moment tensors. Further extensions are in progress or planned, e.g., for macroseismic information, location probability density functions, slip distributions, and ground motion information. The QuakeML language definition is supplemented by a concept to provide resource metadata and facilitate metadata exchange between distributed data providers. For that purpose, we introduce unique, location-independent identifiers of seismological resources. As an application of QuakeML, ETH Zurich currently develops a Python-based seismicity analysis toolkit as a contribution to CSEP (Collaboratory for the Study of Earthquake Predictability). We follow a collaborative and transparent development approach along the lines of the procedures of the World Wide Web Consortium (W3C). QuakeML currently is in working draft status. The standard description will be subjected to a public Request for Comments (RFC) process and eventually reach the status of a recommendation. QuakeML can be found at http://www.quakeml.org.

  20. QuakeML: status of the XML-based seismological data exchange format

    Directory of Open Access Journals (Sweden)

    Joachim Saul

    2011-04-01

    Full Text Available QuakeML is an XML-based data exchange standard for seismology that is in its fourth year of active community-driven development. Its development was motivated by the need to consolidate existing data formats for applications in statistical seismology, as well as setting a cutting-edge, community-agreed standard to foster interoperability of distributed infrastructures. The current release (version 1.2 is based on a public Request for Comments process and accounts for suggestions and comments provided by a broad international user community. QuakeML is designed as an umbrella schema under which several sub-packages are collected. The present scope of QuakeML 1.2 covers a basic description of seismic events including picks, arrivals, amplitudes, magnitudes, origins, focal mechanisms, and moment tensors. Work on additional packages (macroseismic information, ground motion, seismic inventory, and resource metadata has been started, but is at an early stage. Several applications based on the QuakeML data model have been created so far. Among these are earthquake catalog web services at the European Mediterranean Seismological Centre (EMSC, GNS Science, and the Southern California Earthquake Data Center (SCEDC, and QuakePy, an open-source Python-based seismicity analysis toolkit. Furthermore, QuakeML is being used in the SeisComP3 system from GFZ Potsdam, and in the Collaboratory for the Study of Earthquake Predictability (CSEP testing center installations, developed by Southern California Earthquake Center (SCEC. QuakeML is still under active and dynamic development. Further contributions from the community are crucial to its success and are highly welcome.

  1. 20 year IRIS: impact on seismological research at home and abroad

    Science.gov (United States)

    van der Hilst, R. D.

    2004-12-01

    : The positive impact of IRIS, through its programs (GSN, PASSCAL, DMS, EO) and its workshops, on seismological research and community building can hardly be overestimated. The Data Management System has been very successful in bringing data to users for research and education anywhere in the world; it enables routine, and in many cases real time, analysis of massive amounts of waveform data for a spectacularly diverse range of studies. (I will give examples of surface wave tomography and inverse scattering studies of the core mantle boundary.) The support that PASSCAL provides for the planning and execution of field campaigns allows seismologists to shift attention from operational issues to exciting science, and the required data dissemination through DMS does not only result in tremendously valuable data sets but also contributes to community building through (international) collaboration. Europe, Australia, and Asia also have rich histories of network and portable array seismometry, and in many areas the cumulative station density exceeds that of North America (even, perhaps, with USArray). Moreover, in some cases, such as the use of temporary, roving arrays of broad band seismometers, activities overseas may have preceded and inspired developments in the US. However, the absence of effective central systems for management and dissemination of quality-controlled data has left many unique historical and regional data sets underutilized. This situation is changing, however. As an example I will mention the NERIES initiative to build a better infrastructure for seismological research and education in Europe. Apart from providing an example, through international collaboration IRIS can continue to play an important role in the improvement of the global seismological infrastructure.

  2. A short history of Japanese historical seismology: past and the present

    Science.gov (United States)

    Matsu'ura, Ritsuko S.

    2017-12-01

    Since seismicity in Japan is fairly high, Japanese interest in historical seismicity can be traced back to the nineth century, only a few centuries after the formation of the ancient ruling state. A 1000 years later, 2 years earlier than the modern seismological society was founded, the research on historical seismology started in Japan in 1878. By the accumulation for the recent 140 years, the present Japanese seismologists can read many historical materials without reading cursive scripts. We have a convenient access to the historical information related to earthquakes, in the modern characters of 27,759 pages. We now have 214 epicenters of historical earthquakes from 599 ad to 1872. Among them, 134 events in the early modern period were assigned hypocentral depths and proper magnitudes. The intensity data of 8700 places by those events were estimated. These precise intensity data enabled us to compare the detailed source areas of pairs of repeated historical earthquakes, such as the 1703 Genroku earthquake with the 1923 Kanto earthquake, and the 1707 Hoei earthquake with the summation of the 1854 Ansei Tokai and Ansei Nankai earthquakes. It is revealed that the focal area of the former larger event cannot completely include those of the latter smaller earthquakes, although those were believed to be typical sets of characteristic interplate earthquakes at the Sagami trough and at the Nankai trough. Research on historical earthquakes is very important to assess the seismic hazard in the future. We still have one-fifth events of the early modern period to be analyzed in detail. The compilation of places experienced high intensities in the modern events is also necessary. For the ancient and medieval periods, many equivocal events are still left. The further advance of the interdisciplinary research on historical seismology is necessary.

  3. Seismological and Geodynamic Monitoring Network in the "javakheti" Test Zone in the Southern Caucasus

    Science.gov (United States)

    Arakelyan, A.; Babayan, H.; Karakhanyan, A.; Durgaryan, R.; Basilaia, G.; Sokhadze, G.; Bidzinashvili, G.

    2012-12-01

    The Javakheti Highland located in the border region between Armenia and Georgia (sharing a border with Turkey) is an area in the Southern Caucasus of young Holocene-Quaternary volcanism and a region with convergence of a number of active faults. Issues related to the geometry, kinematics and slip-rate of these faults and assessment of their seismic hazard remain unclear in part due to the fragmentary nature of the studies carried out soley within the borders of each of the countries as opposed to region wide. In the frame of the ISTC A-1418 Project "Open network of scientific Centers for mitigation risk of natural hazards in the Southern Caucasus and Central Asia" the Javakheti Highland was selected as a trans-border test-zone. This designation allowed for the expansion and upgrading of the seismological and geodynamic monitoring networks under the auspices of several international projects (ISTC CSP-053 Project "Development of Communication System for seismic hazard situations in the Southern Caucasus and Central Asia", NATO SfP- 983284 Project "Caucasus Seismic Emergency Response") as well as through joint research programs with the National Taiwan University and Institute of Earth Sciences (IES, Taiwan), Universite Montpellier II (France) and Ecole et Observatoire des Sciences de la Terre-Université de Strasbourg (France). Studies of geodynamic processes, and seismicity of the region and their interaction have been carried out utilizing the newly established seismological and geodynamic monitoring networks and have served as a basis for the study of the geologic and tectonic structure . Upgrading and expansion of seismological and geodynamic networks required urgent solutions to the following tasks: Introduction of efficient online systems for information acquisition, accumulation and transmission (including sattelite systems) from permanent and temporary installed stations, Adoption of international standards for organization and management of databases in GIS

  4. Prediction of the area affected by earthquake-induced landsliding based on seismological parameters

    Science.gov (United States)

    Marc, Odin; Meunier, Patrick; Hovius, Niels

    2017-07-01

    We present an analytical, seismologically consistent expression for the surface area of the region within which most landslides triggered by an earthquake are located (landslide distribution area). This expression is based on scaling laws relating seismic moment, source depth, and focal mechanism with ground shaking and fault rupture length and assumes a globally constant threshold of acceleration for onset of systematic mass wasting. The seismological assumptions are identical to those recently used to propose a seismologically consistent expression for the total volume and area of landslides triggered by an earthquake. To test the accuracy of the model we gathered geophysical information and estimates of the landslide distribution area for 83 earthquakes. To reduce uncertainties and inconsistencies in the estimation of the landslide distribution area, we propose an objective definition based on the shortest distance from the seismic wave emission line containing 95 % of the total landslide area. Without any empirical calibration the model explains 56 % of the variance in our dataset, and predicts 35 to 49 out of 83 cases within a factor of 2, depending on how we account for uncertainties on the seismic source depth. For most cases with comprehensive landslide inventories we show that our prediction compares well with the smallest region around the fault containing 95 % of the total landslide area. Aspects ignored by the model that could explain the residuals include local variations of the threshold of acceleration and processes modulating the surface ground shaking, such as the distribution of seismic energy release on the fault plane, the dynamic stress drop, and rupture directivity. Nevertheless, its simplicity and first-order accuracy suggest that the model can yield plausible and useful estimates of the landslide distribution area in near-real time, with earthquake parameters issued by standard detection routines.

  5. Recent advance in polar seismology: Global impact of the International Polar Year

    Science.gov (United States)

    Kanao, Masaki; Zhao, Dapeng; Wiens, Douglas A.; Stutzmann, Éléonore

    2015-03-01

    The most exciting initiative for the recent polar studies was the International Polar Year (IPY) in 2007-2008. The IPY has witnessed a growing community of seismologists who have made considerable efforts to acquire high-quality data in polar regions. It also provided an excellent opportunity to make significant advances in seismic instrumentation of the polar regions to achieve scientific targets involving global issues. Taking these aspects into account, we organize and publish a special issue in Polar Science on the recent advance in polar seismology and cryoseismology as fruitful achievements of the IPY.

  6. European seismological data exchange, access and processing: current status of the Research Infrastructure project NERIES

    Science.gov (United States)

    Giardini, D.; van Eck, T.; Bossu, R.; Wiemer, S.

    2009-04-01

    The EC Research infrastructure project NERIES, an Integrated Infrastructure Initiative in seismology for 2006-2010 has passed its mid-term point. We will present a short concise overview of the current state of the project, established cooperation with other European and global projects and the planning for the last year of the project. Earthquake data archiving and access within Europe has dramatically improved during the last two years. This concerns earthquake parameters, digital broadband and acceleration waveforms and historical data. The Virtual European Broadband Seismic Network (VEBSN) consists currently of more then 300 stations. A new distributed data archive concept, the European Integrated Waveform Data Archive (EIDA), has been implemented in Europe connecting the larger European seismological waveform data. Global standards for earthquake parameter data (QuakeML) and tomography models have been developed and are being established. Web application technology has been and is being developed to make a jump start to the next generation data services. A NERIES data portal provides a number of services testing the potential capacities of new open-source web technologies. Data application tools like shakemaps, lossmaps, site response estimation and tools for data processing and visualisation are currently available, although some of these tools are still in an alpha version. A European tomography reference model will be discussed at a special workshop in June 2009. Shakemaps, coherent with the NEIC application, are implemented in, among others, Turkey, Italy, Romania, Switzerland, several countries. The comprehensive site response software is being distributed and used both inside and outside the project. NERIES organises several workshops inviting both consortium and non-consortium participants and covering a wide range of subjects: ‘Seismological observatory operation tools', ‘Tomography', ‘Ocean bottom observatories', 'Site response software training

  7. Effects of Seismological and Soil Parameters on Earthquake Energy demand in Level Ground Sand Deposits

    Science.gov (United States)

    nabili, sara; shahbazi majd, nafiseh

    2013-04-01

    Liquefaction has been a source of major damages during severe earthquakes. To evaluate this phenomenon there are several stress, strain and energy based approaches. Use of the energy method has been more focused by researchers due to its advantages with respect to other approaches. The use of the energy concept to define the liquefaction potential is validated through laboratory element and centrifuge tests as well as field studies. This approach is based on the hypothesis that pore pressure buildup is directly related to the dissipated energy in sands which is the accumulated areas between the stress-strain loops. Numerous investigations were performed to find a relationship which correlates the dissipated energy to the soil parameters, but there are not sufficient studies to relate this dissipated energy, known as demand energy, concurrently, to the seismological and the soil parameters. The aim of this paper is to investigate the dependency of the demand energy in sands to seismological and the soil parameters. To perform this task, an effective stress analysis has been executed using FLAC finite difference program. Finn model, which is a built-in constitutive model implemented in FLAC program, was utilized. Since an important stage to predict the liquefaction is the prediction of excess pore water pressure at a given point, a simple numerical framework is presented to assess its generation during a cyclic loading in a given centrifuge test. According to the results, predicted excess pore water pressures did not closely match to the measured excess pore water pressure values in the centrifuge test but they can be used in the numerical assessment of excess pore water pressure with an acceptable degree of preciseness. Subsequently, the centrifuge model was reanalyzed using several real earthquake acceleration records with different seismological parameters such as earthquake magnitude and Hypocentral distance. The accumulated energies (demand energy) dissipated in

  8. Seismological database for Banat seismic region (Romania) - Part 1: The parametric earthquake catalogue

    International Nuclear Information System (INIS)

    Oros, E.; Popa, M.; Moldovan, I. A.

    2008-01-01

    The most comprehensive seismological database for Banat seismic region (Romania) has been achieved. This paper refers to the essential characteristics of the first component of this database, namely the Parametric Earthquakes Catalogue for the Banat Seismic Region (PECBSR). PECBSR comprises 7783 crustal earthquakes (3 ≤ h ≤ 25 km) with 0.4 ≤ M i ≥ 5.6 (M i is M L , M D , M S , M W , Mm and/or mb from compiled sources) occurred in the Banat region and its surroundings between years 1443 and 2006. Different magnitude scales were converted into moment magnitude scale, Mw. The completeness of PECBSR strongly depends on the time. (authors)

  9. Evaluation results after seven years of operation for the permanent Hellenic Seismological Network of Crete (HSNC).

    Science.gov (United States)

    Vallianatos, F.; Hloupis, G.; Papadopoulos, I.

    2012-04-01

    The Hellenic arc and the adjacent areas of the Greek mainland are the most active in western Eurasia and some of the most seismically active zones of the world. The seismicity of South Aegean is extremely high and is characterised by the frequent occurrence of large shallow and intermediate depth earthquakes. Until 2004, the installed seismological stations from several providers (NOA, GEOFON, MEDNET) provide average interstation distance around 130km resulting to catalogues with minimum magnitude of completeness (Mc) equals to 3.7. Towards to the direction of providing dense and state of the art instrumental coverage of seismicity in the South Aegean, HSNC begun its operation in 2004. Today it consists of (12) permanent seismological stations equipped with short period and broadband seismographs coupled with 3rd generation 24bit data loggers as well as from (2) accelerographs . The addition of HSNC along with combined use of all the active networks in South Aegean area (NOA, GEOFON, AUTH) decrease the average interstation distance to 60km and provide catalogues with Mc≥3.2. Data transmission and telemetry is implemented by a hybrid network consisting of dedicated wired ADSL links as well as VSAT links by using a unique private satellite hub. Real time data spread over collaborating networks (AUTH) and laboratories (Department of Earth Science - UCL) while at the same time, events are appended automatically and manually to EMSC database. Additional value to the network is provided by means of prototype systems which deployed in-situ for the purposes of: a) Acquiring aftershock data in the minimum time after main event. This is a mobile seismological network called RaDeSeis (Rapid Deployment Seismological network) which consists of a central station acting also as the central communication hub and wifi coupled mobile stations. b) The development of dedicated hardware and software solutions for rapid installation times (around 1 hour for each station) leading to

  10. 25 Years of Research in Earth Physics and One Century of Seismology in Romania

    International Nuclear Information System (INIS)

    Marmureanu, Gh.

    2002-01-01

    The conference '25 Years of Research in Earth Physics and One Century of Seismology in Romania' held at Bucharest, Romania on September 27-29, 2002 was structured as follows: 1. Keynote lectures (4 papers); Section 1 - Exchange of data and improvement of earthquake monitoring during the last 25 years (6 papers); Section 2 - Study of the seismic source (5 papers); Section 3 - Seismotectonics and geodynamics of the Carphato - Balkan area (16 papers); Section 4 - Seismic hazard assesment (14 papers); Section 5 - Earthquake prediction research (7 papers); Section 6 - Lessons from earthquake damage and policies for seismic risk mitigation (3 papers)

  11. Seismological and geological investigation for earthquake hazard in the Greater Accra Metropolitan Area

    International Nuclear Information System (INIS)

    Doku, M. S.

    2013-07-01

    A seismological and geological investigation for earthquake hazard in the Greater Accra Metropolitan Area was undertaken. The research was aimed at employing a methematical model to estimate the seismic stress for the study area by generating a complete, unified and harmonized earthquake catalogue spanning 1615 to 2012. Seismic events were souced from Leydecker, G. and P. Amponsah, (1986), Ambraseys and Adams, (1986), Amponsah (2008), Geological Survey Department, Accra, Ghana, Amponsah (2002), National Earthquake Information Service, United States Geological Survey, Denver, Colorado 80225, USA, the International Seismological Centre and the National Data Centre of the Ghana Atomic Energy Commission. Events occurring in the study area were used to create and Epicentral Intensity Map and a seismicity map of the study area after interpolation of missing seismic magnitudes. The least square method and the maximum likelihood estimation method were employed to evaluate b-values of 0.6 and 0.9 respectively for the study area. A thematic map of epicentral intensity superimposed on the geology of the study area was also developed to help understand the relationship between the virtually fractured, jointed and sheared geology and the seismic events. The results obtained are indicative of the fact that the stress level of GAMA has a telling effect on its seismicity and also the events are prevalents at fractured, jointed and sheared zones. (au)

  12. The CTBTO Link to the database of the International Seismological Centre (ISC)

    Science.gov (United States)

    Bondar, I.; Storchak, D. A.; Dando, B.; Harris, J.; Di Giacomo, D.

    2011-12-01

    The CTBTO Link to the database of the International Seismological Centre (ISC) is a project to provide access to seismological data sets maintained by the ISC using specially designed interactive tools. The Link is open to National Data Centres and to the CTBTO. By means of graphical interfaces and database queries tailored to the needs of the monitoring community, the users are given access to a multitude of products. These include the ISC and ISS bulletins, covering the seismicity of the Earth since 1904; nuclear and chemical explosions; the EHB bulletin; the IASPEI Reference Event list (ground truth database); and the IDC Reviewed Event Bulletin. The searches are divided into three main categories: The Area Based Search (a spatio-temporal search based on the ISC Bulletin), the REB search (a spatio-temporal search based on specific events in the REB) and the IMS Station Based Search (a search for historical patterns in the reports of seismic stations close to a particular IMS seismic station). The outputs are HTML based web-pages with a simplified version of the ISC Bulletin showing the most relevant parameters with access to ISC, GT, EHB and REB Bulletins in IMS1.0 format for single or multiple events. The CTBTO Link offers a tool to view REB events in context within the historical seismicity, look at observations reported by non-IMS networks, and investigate station histories and residual patterns for stations registered in the International Seismographic Station Registry.

  13. The GINGERino ring laser gyroscope, seismological observations at one year from the first light

    Science.gov (United States)

    Simonelli, Andreino; Belfi, Jacopo; Beverini, Nicolò; Di Virgilio, Angela; Carelli, Giorgio; Maccioni, Enrico; De Luca, Gaetano; Saccorotti, Gilberto

    2016-04-01

    The GINGERino ring laser gyroscope (RLG) is a new large observatory-class RLG located in Gran Sasso underground laboratory (LNGS), one national laboratory of the INFN (Istituto Nazionale di Fisica Nucleare). The GINGERino apparatus funded by INFN in the context of a larger project of fundamental physics is intended as a pathfinder instrument to reach the high sensitivity needed to observe general relativity effects; more details are found at the URL (https://web2.infn.it/GINGER/index.php/it/). The sensitivity reached by our instrument in the first year after the set up permitted us to acquire important seismological data of ground rotations during the transit of seismic waves generated by seisms at different epicentral distances. RLGs are in fact the best sensors for capturing the rotational motions associated with the transit of seismic waves, thanks to the optical measurement principle, these instruments are in fact insensitive to translations. Ground translations are recorded by two seismometers: a Nanometrics Trillium 240 s and Guralp CMG 3T 360 s, the first instrument is part of the national earthquake monitoring program of the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and provides the ground translation data to be compared to the RLG rotational data. We report the waveforms and the seismological analysis of some seismic events recorded during our first year of activity inside the LNGS laboratory.

  14. ObspyDMT: a Python toolbox for retrieving and processing large seismological data sets

    Directory of Open Access Journals (Sweden)

    K. Hosseini

    2017-10-01

    Full Text Available We present obspyDMT, a free, open-source software toolbox for the query, retrieval, processing and management of seismological data sets, including very large, heterogeneous and/or dynamically growing ones. ObspyDMT simplifies and speeds up user interaction with data centers, in more versatile ways than existing tools. The user is shielded from the complexities of interacting with different data centers and data exchange protocols and is provided with powerful diagnostic and plotting tools to check the retrieved data and metadata. While primarily a productivity tool for research seismologists and observatories, easy-to-use syntax and plotting functionality also make obspyDMT an effective teaching aid. Written in the Python programming language, it can be used as a stand-alone command-line tool (requiring no knowledge of Python or can be integrated as a module with other Python codes. It facilitates data archiving, preprocessing, instrument correction and quality control – routine but nontrivial tasks that can consume much user time. We describe obspyDMT's functionality, design and technical implementation, accompanied by an overview of its use cases. As an example of a typical problem encountered in seismogram preprocessing, we show how to check for inconsistencies in response files of two example stations. We also demonstrate the fully automated request, remote computation and retrieval of synthetic seismograms from the Synthetics Engine (Syngine web service of the Data Management Center (DMC at the Incorporated Research Institutions for Seismology (IRIS.

  15. Urban Seismology: on the origin of earth vibrations within a city.

    Science.gov (United States)

    Díaz, Jordi; Ruiz, Mario; Sánchez-Pastor, Pilar S; Romero, Paula

    2017-11-10

    Urban seismology has become an active research field in the recent years, both with seismological objectives, as obtaining better microzonation maps in highly populated areas, and with engineering objectives, as the monitoring of traffic or the surveying of historical buildings. We analyze here the seismic records obtained by a broad-band seismic station installed in the ICTJA-CSIC institute, located near the center of Barcelona city. Although this station was installed to introduce visitors to earth science during science fairs and other dissemination events, the analysis of the data has allowed to infer results of interest for the scientific community. The main results include the evidence that urban seismometers can be used as a easy-to-use, robust monitoring tool for road traffic and subway activity inside the city. Seismic signals generated by different cultural activities, including rock concerts, fireworks or football games, can be detected and discriminated from its seismic properties. Beside the interest to understand the propagation of seismic waves generated by those rather particular sources, those earth shaking records provide a powerful tool to gain visibility in the mass media and hence have the opportunity to present earth sciences to a wider audience.

  16. Coronal Seismology of Flare-Excited Standing Slow-Mode Waves Observed by SDO/AIA

    Science.gov (United States)

    Wang, Tongjiang; Ofman, Leon; Davila, Joseph M.

    2016-05-01

    Flare-excited longitudinal intensity oscillations in hot flaring loops have been recently detected by SDO/AIA in 94 and 131 Å bandpasses. Based on the interpretation in terms of a slow-mode wave, quantitative evidence of thermal conduction suppression in hot (>9 MK) loops has been obtained for the first time from measurements of the polytropic index and phase shift between the temperature and density perturbations (Wang et al. 2015, ApJL, 811, L13). This result has significant implications in two aspects. One is that the thermal conduction suppression suggests the need of greatly enhanced compressive viscosity to interpret the observed strong wave damping. The other is that the conduction suppression provides a reasonable mechanism for explaining the long-duration events where the thermal plasma is sustained well beyond the duration of impulsive hard X-ray bursts in many flares, for a time much longer than expected by the classical Spitzer conductive cooling. In this study, we model the observed standing slow-mode wave in Wang et al. (2015) using a 1D nonlinear MHD code. With the seismology-derived transport coefficients for thermal conduction and compressive viscosity, we successfully simulate the oscillation period and damping time of the observed waves. Based on the parametric study of the effect of thermal conduction suppression and viscosity enhancement on the observables, we discuss the inversion scheme for determining the energy transport coefficients by coronal seismology.

  17. Citizen seismology in Taiwan: what went wrong and what is the future?

    Science.gov (United States)

    Chen, K. H.; Liang, W. T.; Wu, Y. F.

    2017-12-01

    Citizen seismology encourages the public involvement to data collection, analysis, and reporting, and has the potential to greatly improve the emergency response to seismic hazard. This of course, is important for scientific achievement due to the dense network. We believed the value of citizen seismology and started with distributing Quake-Catcher-Network (QCN) sensor at schools in Taiwan. While working with teachers, we hoped to motivate the learning of how to read seismograms, what to see in the data, and what to teach in the class. Through lots of workshops and activities, even with near-real time earthquake game competition and board game (quake-nopoly) developed along the way, we came to realize the huge gap between what people need and what we do. And to bridge the gap, a new generation of citizen seismic network is needed. Imagine at work, you receive the alarm from sensors at home that tells you the location, size, and type of anomalous shaking events in the neighborhood. Can this future "warning" system happen, allowing citizen to do emergence response? This is a story about facing the challenge, transforming the doubt of "why do I care" to a future IoT world.

  18. ObspyDMT: a Python toolbox for retrieving and processing large seismological data sets

    Science.gov (United States)

    Hosseini, Kasra; Sigloch, Karin

    2017-10-01

    We present obspyDMT, a free, open-source software toolbox for the query, retrieval, processing and management of seismological data sets, including very large, heterogeneous and/or dynamically growing ones. ObspyDMT simplifies and speeds up user interaction with data centers, in more versatile ways than existing tools. The user is shielded from the complexities of interacting with different data centers and data exchange protocols and is provided with powerful diagnostic and plotting tools to check the retrieved data and metadata. While primarily a productivity tool for research seismologists and observatories, easy-to-use syntax and plotting functionality also make obspyDMT an effective teaching aid. Written in the Python programming language, it can be used as a stand-alone command-line tool (requiring no knowledge of Python) or can be integrated as a module with other Python codes. It facilitates data archiving, preprocessing, instrument correction and quality control - routine but nontrivial tasks that can consume much user time. We describe obspyDMT's functionality, design and technical implementation, accompanied by an overview of its use cases. As an example of a typical problem encountered in seismogram preprocessing, we show how to check for inconsistencies in response files of two example stations. We also demonstrate the fully automated request, remote computation and retrieval of synthetic seismograms from the Synthetics Engine (Syngine) web service of the Data Management Center (DMC) at the Incorporated Research Institutions for Seismology (IRIS).

  19. Super-large optical gyroscopes for applications in geodesy and seismology: state-of-the-art and development prospects

    International Nuclear Information System (INIS)

    Velikoseltsev, A A; Luk'yanov, D P; Vinogradov, V I; Shreiber, K U

    2014-01-01

    A brief survey of the history of the invention and development of super-large laser gyroscopes (SLLGs) is presented. The basic results achieved using SLLGs in geodesy, seismology, fundamental physics and other fields are summarised. The concept of SLLG design, specific features of construction and implementation are considered, as well as the prospects of applying the present-day optical technologies to laser gyroscope engineering. The possibilities of using fibre-optical gyroscopes in seismologic studies are analysed and the results of preliminary experimental studies are presented. (laser gyroscopes)

  20. Super-large optical gyroscopes for applications in geodesy and seismology: state-of-the-art and development prospects

    Energy Technology Data Exchange (ETDEWEB)

    Velikoseltsev, A A; Luk' yanov, D P [St. Petersburg Electrotechnical University ' ' LETI' ' , St. Petersburg (Russian Federation); Vinogradov, V I [OJSC Tambov factory Elektropribor (Russian Federation); Shreiber, K U [Forschungseinrichtung Satellitengeodaesie, Technosche Universitaet Muenchen, Geodaetisches Observatorium Wettzell, Sackenrieder str. 25, 93444 Bad Koetzting (Germany)

    2014-12-31

    A brief survey of the history of the invention and development of super-large laser gyroscopes (SLLGs) is presented. The basic results achieved using SLLGs in geodesy, seismology, fundamental physics and other fields are summarised. The concept of SLLG design, specific features of construction and implementation are considered, as well as the prospects of applying the present-day optical technologies to laser gyroscope engineering. The possibilities of using fibre-optical gyroscopes in seismologic studies are analysed and the results of preliminary experimental studies are presented. (laser gyroscopes)

  1. Real-time GPS seismology using a single receiver: method comparison, error analysis and precision validation

    Science.gov (United States)

    Li, Xingxing

    2014-05-01

    Earthquake monitoring and early warning system for hazard assessment and mitigation has traditional been based on seismic instruments. However, for large seismic events, it is difficult for traditional seismic instruments to produce accurate and reliable displacements because of the saturation of broadband seismometers and problematic integration of strong-motion data. Compared with the traditional seismic instruments, GPS can measure arbitrarily large dynamic displacements without saturation, making them particularly valuable in case of large earthquakes and tsunamis. GPS relative positioning approach is usually adopted to estimate seismic displacements since centimeter-level accuracy can be achieved in real-time by processing double-differenced carrier-phase observables. However, relative positioning method requires a local reference station, which might itself be displaced during a large seismic event, resulting in misleading GPS analysis results. Meanwhile, the relative/network approach is time-consuming, particularly difficult for the simultaneous and real-time analysis of GPS data from hundreds or thousands of ground stations. In recent years, several single-receiver approaches for real-time GPS seismology, which can overcome the reference station problem of the relative positioning approach, have been successfully developed and applied to GPS seismology. One available method is real-time precise point positioning (PPP) relied on precise satellite orbit and clock products. However, real-time PPP needs a long (re)convergence period, of about thirty minutes, to resolve integer phase ambiguities and achieve centimeter-level accuracy. In comparison with PPP, Colosimo et al. (2011) proposed a variometric approach to determine the change of position between two adjacent epochs, and then displacements are obtained by a single integration of the delta positions. This approach does not suffer from convergence process, but the single integration from delta positions to

  2. Crustal Models Assessment in Western Part of Romania Employing Active Seismic and Seismologic Methods

    Science.gov (United States)

    Bala, Andrei; Toma-Danila, Dragos; Tataru, Dragos; Grecu, Bogdan

    2017-12-01

    In the years 1999 - 2000 two regional seismic refraction lines were performed within a close cooperation with German partners from University of Karlsruhe. One of these lines is Vrancea 2001, with 420 km in length, almost half of them recorded in Transylvanian Basin. The structure of the crust along the seismic line revealed a very complicated crustal structure beginning with Eastern Carpathians and continuing in the Transylvanian Basin until Medias. As a result of the development of the National Seismic Network in the last ten years, more than 100 permanent broadband stations are now continuously operating in Romania. Complementary to this national dataset, maintained and developed in the National Institute for Earth Physics, new data emerged from the temporary seismologic networks established during the joint projects with European partners in the last decades. The data gathered so far is valuable both for seismology purposes and crustal structure studies, especially for the western part of the country, where this kind of data were sparse until now. Between 2009 and 2011, a new reference model for the Earth’s crust and mantle of the European Plate was defined through the NERIES project from existing data and models. The database gathered from different kind of measurements in Transylvanian Basin and eastern Pannonian Basin were included in this NERIES model and an improved and upgraded model of the Earth crust emerged for western part of Romania. Although the dataset has its origins in several periods over the last 50 years, the results are homogeneous and they improve and strengthen our image about the depth of the principal boundaries in the crust. In the last chapter two maps regarding these boundaries are constructed, one for mid-crustal boundary and one for Moho. They were build considering all the punctual information available from different sources in active seismic and seismology which are introduced in the general maps from the NERIES project for

  3. Adapting Controlled-source Coherence Analysis to Dense Array Data in Earthquake Seismology

    Science.gov (United States)

    Schwarz, B.; Sigloch, K.; Nissen-Meyer, T.

    2017-12-01

    Exploration seismology deals with highly coherent wave fields generated by repeatable controlled sources and recorded by dense receiver arrays, whose geometry is tailored to back-scattered energy normally neglected in earthquake seismology. Owing to these favorable conditions, stacking and coherence analysis are routinely employed to suppress incoherent noise and regularize the data, thereby strongly contributing to the success of subsequent processing steps, including migration for the imaging of back-scattering interfaces or waveform tomography for the inversion of velocity structure. Attempts have been made to utilize wave field coherence on the length scales of passive-source seismology, e.g. for the imaging of transition-zone discontinuities or the core-mantle-boundary using reflected precursors. Results are however often deteriorated due to the sparse station coverage and interference of faint back-scattered with transmitted phases. USArray sampled wave fields generated by earthquake sources at an unprecedented density and similar array deployments are ongoing or planned in Alaska, the Alps and Canada. This makes the local coherence of earthquake data an increasingly valuable resource to exploit.Building on the experience in controlled-source surveys, we aim to extend the well-established concept of beam-forming to the richer toolbox that is nowadays used in seismic exploration. We suggest adapted strategies for local data coherence analysis, where summation is performed with operators that extract the local slope and curvature of wave fronts emerging at the receiver array. Besides estimating wave front properties, we demonstrate that the inherent data summation can also be used to generate virtual station responses at intermediate locations where no actual deployment was performed. Owing to the fact that stacking acts as a directional filter, interfering coherent wave fields can be efficiently separated from each other by means of coherent subtraction. We

  4. Laboratory-based Interpretation of Seismological Models: Dealing with Incomplete or Incompatible Experimental Data (Invited)

    Science.gov (United States)

    Jackson, I.; Kennett, B. L.; Faul, U. H.

    2009-12-01

    In parallel with cooperative developments in seismology during the past 25 years, there have been phenomenal advances in mineral/rock physics making laboratory-based interpretation of seismological models increasingly useful. However, the assimilation of diverse experimental data into a physically sound framework for seismological application is not without its challenges as demonstrated by two examples. In the first example, that of equation-of-state and elasticity data, an appropriate, thermodynamically consistent framework involves finite-strain expansion of the Helmholz free energy incorporating the Debye approximation to the lattice vibrational energy, as advocated by Stixrude and Lithgow-Bertelloni. Within this context, pressure, specific heat and entropy, thermal expansion, elastic constants and their adiabatic and isothermal pressure derivatives are all calculable without further approximation in an internally consistent manner. The opportunities and challenges of assimilating a wide range of sometimes marginally incompatible experimental data into a single model of this type will be demonstrated with reference to MgO, unquestionably the most thoroughly studied mantle mineral. A neighbourhood-algorithm inversion has identified a broadly satisfactory model, but uncertainties in key parameters associated particularly with pressure calibration remain sufficiently large as to preclude definitive conclusions concerning lower-mantle chemical composition and departures from adiabaticity. The second example is the much less complete dataset concerning seismic-wave dispersion and attenuation emerging from low-frequency forced-oscillation experiments. Significant progress has been made during the past decade towards an understanding of high-temperature, micro-strain viscoelastic relaxation in upper-mantle materials, especially as regards the roles of oscillation period, temperature, grain size and melt fraction. However, the influence of other potentially important

  5. Seismology of Giant Planets: General Overview and Results from the Kepler K2 Observations of Neptune

    Directory of Open Access Journals (Sweden)

    Gaulme Patrick

    2017-01-01

    Full Text Available For this invited contribution, I was asked to give an overview about the application of helio and aster-oseismic techniques to study the interior of giant planets, and to specifically present the recent observations of Neptune by Kepler K2. Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light reflected by planetary atmospheres, and ring seismology in the specific case of Saturn. The current decade has been promising thanks to the detection of Jupiter's acoustic oscillations with the ground-based imaging-spectrometer SYMPA and indirect detection of Saturn's f-modes in its rings by the NASA Cassini orbiter. This has motivated new projects of ground-based and space-borne instruments that are under development. The K2 observations represented the first opportunity to search for planetary oscillations with visible photometry. Despite the excellent quality of K2 data, the noise level of the power spectrum of the light curve was not low enough to detect Neptune's oscillations. The main results from the

  6. Seismology of Giant Planets: General Overview and Results from the Kepler K2 Observations of Neptune

    Science.gov (United States)

    Gaulme, Patrick

    2017-10-01

    For this invited contribution, I was asked to give an overview about the application of helio and aster-oseismic techniques to study the interior of giant planets, and to specifically present the recent observations of Neptune by Kepler K2. Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light reflected by planetary atmospheres, and ring seismology in the specific case of Saturn. The current decade has been promising thanks to the detection of Jupiter's acoustic oscillations with the ground-based imaging-spectrometer SYMPA and indirect detection of Saturn's f-modes in its rings by the NASA Cassini orbiter. This has motivated new projects of ground-based and space-borne instruments that are under development. The K2 observations represented the first opportunity to search for planetary oscillations with visible photometry. Despite the excellent quality of K2 data, the noise level of the power spectrum of the light curve was not low enough to detect Neptune's oscillations. The main results from the K2 observations are

  7. The Hellenic Seismological Network Of Crete (HSNC): Validation and results of the 2013 aftershock sequences

    Science.gov (United States)

    Chatzopoulos, Georgios; Papadopoulos, Ilias; Vallianatos, Filippos

    2015-04-01

    The number and quality of seismological networks in Europe has increased in the past decades. Nevertheless, the need for localized networks monitoring areas of great seismic and scientific interest is constant. Hellenic Seismological Network of Crete (HSNC) covers this need for the vicinity of the South Aegean Sea and Crete Island. In the present work with the use of Z-map software (www.seismo.ethz.ch) the spatial variability of Magnitude of Completeness (Mc) is calculated from HSNC's manual analysis catalogue of events for the period 2011 until today, proving the good coverage of HSNC in the areas. Furthermore the 2013, South Aegean seismicity where two large shallow earthquakes occurred in the vicinity of Crete Island, is discussed. The first event takes place on 15th June 2013 in the front of the Hellenic Arc, south from central Crete, while the second one on 12th October, 2013 on the western part of Crete. The two main shocks and their aftershock sequences have been relocated with the use of hypoinverse earthquake location software and an appropriate crust model. The HSNC identified more than 500 and 300 aftershocks respectively followed after the main events. The detailed construction of aftershocks catalogue permits the applicability of modern theories based on complexity sciences as described recently in the frame of non extensive statistical physics. In addition site effects in the stations locations are presented using event and noise recordings. This work was implemented through the project IMPACT-ARC in the framework of action "ARCHIMEDES III-Support of Research Teams at TEI of Crete" (MIS380353) of the Operational Program "Education and Lifelong Learning" and is co-financed by the European Union (European Social Fund) and Greek national funds References A. Tzanis and F. Vallianatos, "Distributed power-law seismicity changes and crustal deformation in the EW Hellenic Arc", Natural Hazards and Earth Systems Sciences, 3, 179-195, 2003 F. Vallianatos, G

  8. Promoting seismology education through collaboration between university research scientists and school teachers

    Science.gov (United States)

    Brunt, M. R.; Ellins, K. K.; Boyd, D.; Mote, A. S.; Pulliam, J.; Frohlich, C. A.

    2012-12-01

    Participation in the NSF-sponsored Texas Earth and Space Science (TXESS) Revolution teacher professional development project paved the way for several teachers to receive educational seismometers and join the IRIS Seismograph in Schools program. This, in turn, has led to secondary school teachers working with university seismologists on research projects. Examples are the NSF-EarthScope SIEDCAR (Seismic Investigation of Edge Driven Convection Associated with the Rio Grande Rift) project; field studies to compile felt-reports for Texas earthquakes, some which may have been induced by human activities; and a seismic study of the Texas Gulf Coast to investigate ocean-continent transition processes along a passive margin. Such collaborations are mutually beneficial in nature. They help scientists to accomplish their research objectives, involve teachers and their students in the authentic, inquiry-based science, promote public awareness of such projects, and open the doors to advancement opportunities for those teachers involved. In some cases, bringing together research scientists and teachers results in collaborations that produce publishable research. In order to effectively integrate seismology research into 7-12 grade education, one of us (Brunt) established the Eagle Pass Junior High Seismology Team in connection with IRIS Seismograph in Schools, station EPTX (AS-1 seismograph), to teach students about earthquakes using authentic real-time data. The concept has sparked interest among other secondary teachers, leading to the creation of two similarly organized seismology teams: WPTX (Boyd, Williams Preparatory School, Dallas) and THTX (Mote, Ann Richards School for Young Women Leaders, Austin). Although the educational seismometers are basic instruments, they are effective educational tools. Seismographs in schools offer students opportunities to learn how earthquakes are recorded and how modern seismometers work, to collect and interpret seismic data, and to

  9. The "Tsunami Earthquake" of 13 April 1923 in Northern Kamchatka: Seismological and Hydrodynamic Investigations

    Science.gov (United States)

    Salaree, Amir; Okal, Emile A.

    2018-04-01

    We present a seismological and hydrodynamic investigation of the earthquake of 13 April 1923 at Ust'-Kamchatsk, Northern Kamchatka, which generated a more powerful and damaging tsunami than the larger event of 03 February 1923, thus qualifying as a so-called "tsunami earthquake". On the basis of modern relocations, we suggest that it took place outside the fault area of the mainshock, across the oblique Pacific-North America plate boundary, a model confirmed by a limited dataset of mantle waves, which also confirms the slow nature of the source, characteristic of tsunami earthquakes. However, numerical simulations for a number of legitimate seismic models fail to reproduce the sharply peaked distribution of tsunami wave amplitudes reported in the literature. By contrast, we can reproduce the distribution of reported wave amplitudes using an underwater landslide as a source of the tsunami, itself triggered by the earthquake inside the Kamchatskiy Bight.

  10. The West-African craton margin in eastern Senegal: a seismological study

    International Nuclear Information System (INIS)

    Dorbath, Catherine; Dorbath, Louis; Gaulon, Roland; Le Page, Alain

    1983-01-01

    A vertical short period seismological array was operated for six months in earstern Senegal. Large P wave travel-time anomalies are in fairly good relation with the gravity and geological features. Two-dimensional inversion of the data shows the existence of a major vertical discontinuity extending from the surface to 150-200 km depth. The other heterogeneities are mainly located in the crust and related to specific segments of the regional geology: craton, Mauritanides and Senegalo-Mauritanian basin. The main discontinuity dipping to the east is interpreted as the trace of an old subduction slab. We propose the following geodynamical process to explain the formation of the Mauritanides orogenic belt: continental collision after opening of a back-arc marginal basin in late Precambrian and its closure until Devonian

  11. Research and development activities of the Seismology Section for the period January 1982-December 1983

    International Nuclear Information System (INIS)

    Roy, Falguni

    1984-01-01

    The research and development activities of the Seismology Section of the Bhabha Atomic Research Centre (BARC) at Bombay are reported for the period January 1982-December 1983 in the form of summaries. The Section's activities are mainly directed towards detection of underground nuclear explosions. During the report period 64 signals out of about 12000 seismograms which were examined were identified as the signals due to underground nuclear explosions. The instrumentation work for Kolar rockburst research was almost completed under the collaboration programme of BARC with Bharat Gold Mines Ltd. Analytical methods have been developed for interpreting the frequency-magnitude relation of earthquake. These methods will be useful in the seismic estimation of risk in case only restricted data involving events of low magnitude are available. A list of publications of the staff-members of the Section during the report period is given. (M.G.B.)

  12. A Serviced-based Approach to Connect Seismological Infrastructures: Current Efforts at the IRIS DMC

    Science.gov (United States)

    Ahern, Tim; Trabant, Chad

    2014-05-01

    As part of the COOPEUS initiative to build infrastructure that connects European and US research infrastructures, IRIS has advocated for the development of Federated services based upon internationally recognized standards using web services. By deploying International Federation of Digital Seismograph Networks (FDSN) endorsed web services at multiple data centers in the US and Europe, we have shown that integration within seismological domain can be realized. By deploying identical methods to invoke the web services at multiple centers this approach can significantly ease the methods through which a scientist can access seismic data (time series, metadata, and earthquake catalogs) from distributed federated centers. IRIS has developed an IRIS federator that helps a user identify where seismic data from global seismic networks can be accessed. The web services based federator can build the appropriate URLs and return them to client software running on the scientists own computer. These URLs are then used to directly pull data from the distributed center in a very peer-based fashion. IRIS is also involved in deploying web services across horizontal domains. As part of the US National Science Foundation's (NSF) EarthCube effort, an IRIS led EarthCube Building Block's project is underway. When completed this project will aid in the discovery, access, and usability of data across multiple geoscienece domains. This presentation will summarize current IRIS efforts in building vertical integration infrastructure within seismology working closely with 5 centers in Europe and 2 centers in the US, as well as how we are taking first steps toward horizontal integration of data from 14 different domains in the US, in Europe, and around the world.

  13. ObsPy: A Python Toolbox for Seismology - Recent Developments and Applications

    Science.gov (United States)

    Megies, T.; Krischer, L.; Barsch, R.; Sales de Andrade, E.; Beyreuther, M.

    2014-12-01

    ObsPy (http://www.obspy.org) is a community-driven, open-source project dedicated to building a bridge for seismology into the scientific Python ecosystem. It offersa) read and write support for essentially all commonly used waveform, station, and event metadata file formats with a unified interface,b) a comprehensive signal processing toolbox tuned to the needs of seismologists,c) integrated access to all large data centers, web services and databases, andd) convenient wrappers to legacy codes like libtau and evalresp.Python, currently the most popular language for teaching introductory computer science courses at top-ranked U.S. departments, is a full-blown programming language with the flexibility of an interactive scripting language. Its extensive standard library and large variety of freely available high quality scientific modules cover most needs in developing scientific processing workflows. Together with packages like NumPy, SciPy, Matplotlib, IPython, Pandas, lxml, and PyQt, ObsPy enables the construction of complete workflows in Python. These vary from reading locally stored data or requesting data from one or more different data centers through to signal analysis and data processing and on to visualizations in GUI and web applications, output of modified/derived data and the creation of publication-quality figures.ObsPy enjoys a large world-wide rate of adoption in the community. Applications successfully using it include time-dependent and rotational seismology, big data processing, event relocations, and synthetic studies about attenuation kernels and full-waveform inversions to name a few examples. All functionality is extensively documented and the ObsPy tutorial and gallery give a good impression of the wide range of possible use cases.We will present the basic features of ObsPy, new developments and applications, and a roadmap for the near future and discuss the sustainability of our open-source development model.

  14. "Earth, from inside and outside - school activities based on seismology and astronomy"

    Science.gov (United States)

    Chivarean, Radu

    2016-04-01

    Through a multidisciplinary work that integrates Geography education with the other Earth Sciences, we developed an educational project to raise the students' awareness of seismic hazard and to disseminate good practices of earthquake safety. The Romanian Educational Seismic Network (ROEDUSEIS) project (started in 2012) is developed and implemented in partnership with schools from different Romanian cities, our school being one of these. In each participating school a SEP educational seismometer is installed. It is the first educational initiative in Romania in the field of seismology involving the National Institute for Earth Physics - NIEP as coordinator. The e-learning platform website (http://www.roeduseis.ro) represents a great opportunity for students to use real advanced research instruments and scientific data analysis tools in their everyday school activities and a link to observations of Earth phenomena and Earth science in general. The most important educational objectives are related to: preparing comprehensive educational materials as resources for training students and teachers in the analysis and interpretation of seismological data, experimentation of new technologies in projecting and implementing new didactic activities, professional development and support for teachers and development of science curriculum module. The scientific objective is to introduce in schools the use of scientific instruments like seismometer and experimental methods (seismic data analysis). The educational materials entitled "Earthquakes and their effects" is organized in a guide for teachers accompanied by a booklet for students. The structure of the educational material is divided in theoretical chapters followed by sections with activities and experiments adapted to the level of understanding particular to our students. The ROEDUSEIS e-platform should be considered as a modern method for teaching and learning that integrates and completes the work in classroom. The

  15. Proceedings of the OECD/NEA workshop on the relations between seismological data and seismic engineering

    International Nuclear Information System (INIS)

    2003-01-01

    The Committee on the Safety of Nuclear Installations (CSNI) of the OECD-NEA co-ordinates the NEA activities concerning the technical aspects of design, construction and operation of nuclear installations insofar as they affect the safety of such installations. The Integrity and Ageing Working Group (IAGE WG) of the CSNI deals with the integrity of structures and components, and has three sub-groups, dealing with the integrity of metal components and structures, ageing of concrete structures, and the seismic behaviour of structures. The sub-group dealing with the seismic behaviour of structures proposed this workshop. The OECD-NEA workshop on the relations between seismological data and seismic engineering analyses was held on October 17-18, 2002. A field visits in the Izmit area where the fault scarp is still visible was organised on Wednesday October 16, 2002. The Ttirkiye Atom Enerjisi Kurumu, TAEK (Turkish Atomic Energy Agency) in Istanbul, Turkey, hosted the workshop. A recommendation of the OECD workshop on the engineering characterisation of seismic input (hosted by the United States Nuclear Regulatory Commission and organised by Brookhaven National Laboratory on November 15-17, 1999) was to foster the growth of interaction between 'design engineers' and 'ground motion specialists'. The objective of the Istanbul workshop is to address this recommendation. The workshop gave seismologists the opportunity to present observed damages and their related ground motions and design engineers the opportunity to present current techniques used in the evaluation of seismic hazards. Bridging the gap between these two fields was a key objective - this workshop was a forum for bringing together the two communities. In addition, the location of the workshop was particularly interesting and provided possibilities for several of the host country participants to discuss the 1999 Kocaeli earthquake. On the basis of lessons learned from large earthquakes over the last decade, the

  16. Rebuild of the Bulletin of the International Seismological Centre (ISC), part 1: 1964-1979

    Science.gov (United States)

    Storchak, Dmitry A.; Harris, James; Brown, Lonn; Lieser, Kathrin; Shumba, Blessing; Verney, Rebecca; Di Giacomo, Domenico; Korger, Edith I. M.

    2017-12-01

    The data from the Bulletin of the International Seismological Centre (ISC) have always been and still remain in demand for a wide range of studies in Geosciences. The unique features of the Bulletin include long-term coverage (1904-present), the most comprehensive set of included seismic data from the majority of permanent seismic networks at any given time in the history of instrumental recording (currently 150) and homogeneity of the data and their representation. In order to preserve this homogeneity, the ISC has followed its own standard seismic event processing procedures that have not substantially changed until the early 2000s. Several considerable and necessary advancements in the ISC data collection and seismic event location procedures have created a need to rebuild the data for preceding years in line with the new procedures. Thus was set up a project to rebuild the ISC Bulletin for the period from the beginning of the ISC data till the end of data year 2010. The project is known as the Rebuild of the ISC Bulletin. From data month of January 2011, the ISC data have already been processed with the fully tested and established new procedures and do not require an alteration. It was inconceivable even to think about such a project for many tens of years, but great advances in computer power and increased support by the ISC Member-Institutions and Sponsors have given us a chance to perform this project. Having obtained a lot of experience on the way, we believe that within a few years the entire period of the ISC data will be reprocessed and extended for the entire period of instrumental seismological recordings from 1904 till present. The purpose of this article is to describe the work on reprocessing the ISC Bulletin data under the Rebuild project. We also announce the release of the rebuilt ISC Bulletin for the period 1964-1979 with all seismic events reprocessed and relocated in line with the modern ISC procedures, 68,000 new events, 255 new stations

  17. It’s our Fault: Immersing Young Learners in Authentic Practices of Seismology

    Science.gov (United States)

    Kilb, D. L.; Moher, T.; Wiley, J.

    2009-12-01

    The scalable RoomQuake seismology project uses a learning technology framework-embedded phenomena (Moher, 2006)—that simulates seismic phenomena mapped directly onto the physical space of classrooms. This project, aimed at the upper elementary level, situates students as the scientists engaged in an extended investigation designed to discover the spatial, temporal, and intensity distributions of a series of earthquakes. This project emulates earthquake occurrence over a condensed time and spatial span, with students mapping an earthquake fault imagined to be running through their classroom. The students learn: basic seismology terms; ability to identify seismic P- and S-waves; skills associated with trilateration; nomogram/graph reading skills; and the ability to recognize the emergence of a fault based on RoomQuake geometries. From the students’ perspectives, and similar to real-world earthquakes, RoomQuakes occur at unknown times over the course of several weeks. Multiple computers distributed around the perimeter of the classroom serve as simulated seismographs that depict continuous strip-chart seismic recordings. Most of the time the seismograms reflect background noise, but at (apparently) unpredictable times a crescendoing rumble (emanating from a subwoofer) signals a RoomQuake. Hearing this signal, students move to the seismic stations to read the strip charts. Next, the students trilaterate the RoomQuake epicenter by arcing calibrated strings of length proportional to S-P latencies from each seismic station until a common point is identified. Each RoomQuake epicenter is marked by hanging a Styrofoam ball (color-coded by magnitude) from the ceiling. The developing ‘fault’ within the classroom provides an immersive historic record of the RoomQuake’s spatial distribution. Students also maintain a temporal record of events on a large time-line on the wall (recognizing time-related phenomena like aftershocks) and a record of magnitude frequencies on

  18. Complex inner core of the Earth: The last frontier of global seismology

    Science.gov (United States)

    Tkalčić, Hrvoje

    2015-03-01

    The days when the Earth's inner core (IC) was viewed as a homogeneous solid sphere surrounded by the liquid outer core (OC) are now behind us. Due to a limited number of data sampling the IC and a lack of experimentally controlled conditions in the deep Earth studies, it has been difficult to scrutinize competitive hypotheses in this active area of research. However, a number of new concepts linking IC structure and dynamics has been proposed lately to explain different types of seismological observations. A common denominator of recent observational work on the IC is increased complexity seen in IC physical properties such as its isotropic and anisotropic structure, attenuation, inner core boundary (ICB) topography, and its rotational dynamics. For example, small-scale features have been observed to exist as a widespread phenomenon in the uppermost inner core, probably superimposed on much longer-scale features. The characterization of small-scale features sheds light on the nature of the solidification process and helps in understanding seismologically observed hemispherical dichotomy of the IC. The existence of variations in the rate and level of solidification is a plausible physical outcome in an environment where vigorous compositional convection in the OC and variations in heat exchange across the ICB may control the process of crystal growth. However, further progress is hindered by the fact that the current traveltime data of PKIKP waves traversing the IC do not allow discriminating between variations in isotropic P wave velocity and velocity anisotropy. Future studies of attenuation in the IC might provide crucial information about IC structure, although another trade-off exists—that of the relative contribution of scattering versus viscoelastic attenuation and the connection with the material properties. Future installations of dense arrays, cross paths of waves that sample the IC, and corresponding array studies will be a powerful tool to image and

  19. Autonomous BBOBS-NX (NX-2G) for New Era of Ocean Bottom Broadband Seismology

    Science.gov (United States)

    Shiobara, H.; Ito, A.; Sugioka, H.; Shinohara, M.

    2017-12-01

    The broadband ocean bottom seismometer (BBOBS) and its new generation system (BBOBS-NX) have been developed in Japan, and we performed several test and practical observations to create and establish a new category of the ocean floor broadband seismology, since 1999. Now, the data obtained by our BBOBS and BBOBS-NX is proved to be adequate for broadband seismic analyses. Especially, the BBOBS-NX can obtain the horizontal data comparable to land sites in longer periods (10 s -). Moreover, the BBOBST-NX is in practical evaluation for the mobile tilt observation that enables dense geodetic monitoring. The BBOBS-NX system is a powerful tool, although, it has intrinsic limitation of the ROV operation. If this system can be used without the ROV, like as the BBOBS, it should lead us a true breakthrough of ocean bottom seismology. Hereafter, the new autonomous BBOBS-NX is noted as NX-2G in short. The main problem to realize the NX-2G is a tilt of the sensor unit on landing, which exceed the acceptable limit (±8°) in about 50%. As we had no evidence at which moment and how this tilt occurred, we tried to observe it during the BBOBST-NX landing in 2015 by attaching a video camera and an acceleration logger. The result shows that the tilt on landing was determined by the final posture of the system at the penetration into the sediment, and the large oscillating tilt more than ±10° was observed in descending. The function of the NX-2G system is based on 3 stage operations as shown in the image. The glass float is aimed not only to obtain enough buoyancy to extract the sensor unit, but also to suppress the oscillating tilt of the system in descending. In Oct. 2016, we made the first in-situ test of the NX-2G system with a ROV. It was dropped from the sea surface with the video camera and the acceleration logger. The ROV was used to watch the operation of the system at the seafloor. The landing looked well and it was examined from the acceleration data. As the maximum tilt in

  20. Towards monitoring the englacial fracture state using virtual-reflector seismology

    Science.gov (United States)

    Lindner, F.; Weemstra, C.; Walter, F.; Hadziioannou, C.

    2018-04-01

    In seismology, coda wave interferometry (CWI) is an effective tool to monitor time-lapse changes using later arriving, multiply scattered coda waves. Typically, CWI relies on an estimate of the medium's impulse response. The latter is retrieved through simple time-averaging of receiver-receiver cross-correlations of the ambient field, i.e. seismic interferometry (SI). In general, the coda are induced by heterogeneities in the Earth. Being comparatively homogeneous, however, ice bodies such as glaciers and ice sheets exhibit little scattering. In addition, the temporal stability of the time-averaged cross-correlations suffers from temporal variations in the distribution and amplitude of the passive seismic sources. Consequently, application of CWI to ice bodies is currently limited. Nevertheless, fracturing and changes in the englacial macroscopic water content alter the bulk elastic properties of ice bodies, which can be monitored with cryoseismological measurements. To overcome the current limited applicability of CWI to ice bodies, we therefore introduce virtual-reflector seismology (VRS). VRS relies on a so-called multidimensional deconvolution (MDD) process of the time-averaged crosscorrelations. The technique results in the retrieval of a medium response that includes virtual reflections from a contour of receivers enclosing the region of interest (i.e., the region to be monitored). The virtual reflections can be interpreted as artificial coda replacing the (lacking) natural scattered coda. Hence, this artificial coda might be exploited for the purpose of CWI. From an implementation point of view, VRS is similar to SI by MDD, which, as its name suggests, also relies on a multidimensional deconvolution process. SI by MDD, however, does not generate additional virtual reflections. Advantageously, both techniques mitigate spurious coda changes associated with temporal variations in the distribution and amplitude of the passive seismic sources. In this work, we

  1. Using Social Networks to Educate Seismology to Non-Science Audiences in Costa Rica

    Science.gov (United States)

    Lücke, O. H.; Linkimer, L.

    2013-12-01

    Costa Rica has a very high rate of seismicity with 63 damaging earthquakes in its history as a nation and 12 felt earthquakes per month on average. In Costa Rica, earthquakes are part of everyday life; hence the inhabitants are highly aware of seismic activity and geological processes. However, formal educational programs and mainstream media have not yet addressed the appropriate way of educating the public on these topics, thus myths and misconceptions are common. With the increasing influence of social networks on information diffusion, they have become a new channel to address this issue in Costa Rica. The National Seismological Network of Costa Rica (RSN) is a joint effort between the University of Costa Rica and the Costa Rican Institute of Electricity. Since 1973, the RSN studies the seismicity and volcanic activity in the country. Starting on January 2011 the RSN has an active Facebook Page, in which felt earthquakes are reported and information on Seismology, geological processes, scientific talks, and RSN activities are routinely posted. Additionally, RSN gets almost instantaneous feedback from RSN followers including people from all rural and urban areas of Costa Rica. In this study, we analyze the demographics, geographic distribution, reach of specific Facebook posts per topic, and the episodic growth of RSN followers related to specific seismic events. We observe that 70 % of the RSN users are between ages from 18 to 34. We consistently observe that certain regions of the country have more Facebook activity, although those regions are not the most populated nor have a high connectivity index. We interpret this pattern as the result of a higher awareness to geological hazards in those specific areas. We notice that educational posts are as well 'liked' as most earthquake reports. For exceptional seismic events, we observe sudden increments in the number of RSN followers in the order of tens of thousands. For example, the May 2013 Sixaola earthquake (Mw

  2. Seismology in Schools an integrated approach to funding developing and implementing a coordinated programme for teachers and high school students

    Science.gov (United States)

    Blake, T. A.; Jones, A. G.; Campbell, G.

    2010-12-01

    Statistics in Ireland show that physics at Advanced Level in Secondary Schools is declining in popularity and is the most likely subject to be cut first from the curriculum in a curriculum readjustment by school authorities. In an attempt to attract students to study Earth science and seismology the School of Cosmic Physics, DIAS embarked on an outreach programme in 2007 to promote Earth science, particularly seismology, in schools at both Primary and Secondary Levels. Since its inception, DIAS's Seismology in Schools programme has been very well received, with seismometers installed in over fifty schools across the State. Although this number may appear small, given that the population of Ireland is 4M this number of 1 per 80,000 compares favourably with the U.K. (70 in a population of 70M, 1 per 1M) and the U.S.A. (200 in a population of 300M, 1 per 1.5M) with an penetration of 15-20 times greater. The phenomenal success of our Seismology in Schools programme has been helped significantly by the support we have received from the British Geological Survey (BGS) and IRIS (Incorporated Research Institutions for Seismology) in terms of hardware, software and advice. Similarly, the programme would be a pale reflection of what it is today if the Directors of the Educational Centres (ATECI, Association of Teacher's/Education Centres in Ireland) across Ireland had not become enthused and funded the purchase of 34 additional seismometers, and the Geological Survey of Ireland purchased a further six. Also, funding support from Discover Science and Engineering (DSE) was absolutely critical for us to roll out this hugely enlarged programme of 50 seismometers from the originally envisioned four. As this programme is an initiation into seismology for students, it is important to stress that the seismometer is not used in the schools as a professional recording instrument but helps students visualize what seismology and the recording of earthquakes comprises. Essential to the

  3. The 21 August 2017 Ischia (Italy) Earthquake Source Model Inferred From Seismological, GPS, and DInSAR Measurements

    Science.gov (United States)

    De Novellis, V.; Carlino, S.; Castaldo, R.; Tramelli, A.; De Luca, C.; Pino, N. A.; Pepe, S.; Convertito, V.; Zinno, I.; De Martino, P.; Bonano, M.; Giudicepietro, F.; Casu, F.; Macedonio, G.; Manunta, M.; Cardaci, C.; Manzo, M.; Di Bucci, D.; Solaro, G.; Zeni, G.; Lanari, R.; Bianco, F.; Tizzani, P.

    2018-03-01

    The causative source of the first damaging earthquake instrumentally recorded in the Island of Ischia, occurred on 21 August 2017, has been studied through a multiparametric geophysical approach. In order to investigate the source geometry and kinematics we exploit seismological, Global Positioning System, and Sentinel-1 and COSMO-SkyMed differential interferometric synthetic aperture radar coseismic measurements. Our results indicate that the retrieved solutions from the geodetic data modeling and the seismological data are plausible; in particular, the best fit solution consists of an E-W striking, south dipping normal fault, with its center located at a depth of 800 m. Moreover, the retrieved causative fault is consistent with the rheological stratification of the crust in this zone. This study allows us to improve the knowledge of the volcano-tectonic processes occurring on the Island, which is crucial for a better assessment of the seismic risk in the area.

  4. Separation of Stochastic and Deterministic Information from Seismological Time Series with Nonlinear Dynamics and Maximum Entropy Methods

    International Nuclear Information System (INIS)

    Gutierrez, Rafael M.; Useche, Gina M.; Buitrago, Elias

    2007-01-01

    We present a procedure developed to detect stochastic and deterministic information contained in empirical time series, useful to characterize and make models of different aspects of complex phenomena represented by such data. This procedure is applied to a seismological time series to obtain new information to study and understand geological phenomena. We use concepts and methods from nonlinear dynamics and maximum entropy. The mentioned method allows an optimal analysis of the available information

  5. VERCE: a productive e-Infrastructure and e-Science environment for data-intensive seismology research

    Science.gov (United States)

    Vilotte, J. P.; Atkinson, M.; Spinuso, A.; Rietbrock, A.; Michelini, A.; Igel, H.; Frank, A.; Carpené, M.; Schwichtenberg, H.; Casarotti, E.; Filgueira, R.; Garth, T.; Germünd, A.; Klampanos, I.; Krause, A.; Krischer, L.; Leong, S. H.; Magnoni, F.; Matser, J.; Moguilny, G.

    2015-12-01

    Seismology addresses both fundamental problems in understanding the Earth's internal wave sources and structures and augmented societal applications, like earthquake and tsunami hazard assessment and risk mitigation; and puts a premium on open-data accessible by the Federated Digital Seismological Networks. The VERCE project, "Virtual Earthquake and seismology Research Community e-science environment in Europe", has initiated a virtual research environment to support complex orchestrated workflows combining state-of-art wave simulation codes and data analysis tools on distributed computing and data infrastructures (DCIs) along with multiple sources of observational data and new capabilities to combine simulation results with observational data. The VERCE Science Gateway provides a view of all the available resources, supporting collaboration with shared data and methods, with data access controls. The mapping to DCIs handles identity management, authority controls, transformations between representations and controls, and access to resources. The framework for computational science that provides simulation codes, like SPECFEM3D, democratizes their use by getting data from multiple sources, managing Earth models and meshes, distilling them as input data, and capturing results with meta-data. The dispel4py data-intensive framework allows for developing data-analysis applications using Python and the ObsPy library, which can be executed on different DCIs. A set of tools allows coupling with seismology and external data services. Provenance driven tools validate results and show relationships between data to facilitate method improvement. Lessons learned from VERCE training lead us to conclude that solid-Earth scientists could make significant progress by using VERCE e-science environment. VERCE has already contributed to the European Plate Observation System (EPOS), and is part of the EPOS implementation phase. Its cross-disciplinary capabilities are being extended

  6. A Comparative Analysis of Seismological and Gravimetric Crustal Thicknesses below the Andean Region with Flat Subduction of the Nazca Plate

    Directory of Open Access Journals (Sweden)

    Mario E. Gimenez

    2009-01-01

    Full Text Available A gravimetric study was carried out in a region of the Central Andean Range between 28∘ and 32∘ south latitudes and from 72∘ and 66∘ west longitudes. The seismological and gravimetrical Moho models were compared in a sector which coincides with the seismological stations of the CHARGE project. The comparison reveals discrepancies between the gravity Moho depths and those obtained from seismological investigations (CHARGE project, the latter giving deeper values than those resulting from the gravimetric inversion. These discrepancies are attenuated when the positive gravimetric effect of the Nazca plate is considered. Nonetheless, a small residuum of about 5 km remains beneath the Cuyania terrane region, to the east of the main Andean chain. This residuum could be gravimetrically justified if the existence of a high density or eclogitized portion of the lower crust is considered. This result differed from the interpretations from Project “CHARGE” which revealed that the entire inferior crust extending from the Precordillera to the occidental “Sierras Pampeanas” could be “eclogitized”. In this same sector, we calculated the effective elastic thickness (Te of the crust. These results indicated an anomalous value of Te = 30 km below the Cuyania terrane. This is further conclusive evidence of the fact that the Cuyania terrane is allochthonous, for which also geological evidences exist.

  7. SEISMOLOGY OF A LARGE SOLAR CORONAL LOOP FROM EUVI/STEREO OBSERVATIONS OF ITS TRANSVERSE OSCILLATION

    International Nuclear Information System (INIS)

    Verwichte, E.; Van Doorsselaere, T.; Foullon, C.; Nakariakov, V. M.; Aschwanden, M. J.

    2009-01-01

    The first analysis of a transverse loop oscillation observed by both Solar TErrestrial RElations Observatories (STEREO) spacecraft is presented, for an event on the 2007 June 27 as seen by the Extreme Ultraviolet Imager (EUVI). The three-dimensional loop geometry is determined using a three-dimensional reconstruction with a semicircular loop model, which allows for an accurate measurement of the loop length. The plane of wave polarization is found from comparison with a simulated loop model and shows that the oscillation is a fundamental horizontally polarized fast magnetoacoustic kink mode. The oscillation is characterized using an automated method and the results from both spacecraft are found to match closely. The oscillation period is 630 ± 30 s and the damping time is 1000 ± 300 s. Also, clear intensity variations associated with the transverse loop oscillations are reported for the first time. They are shown to be caused by the effect of line-of-sight integration. The Alfven speed and coronal magnetic field derived using coronal seismology are discussed. This study shows that EUVI/STEREO observations achieve an adequate accuracy for studying long-period, large-amplitude transverse loop oscillations.

  8. USING HINODE/EXTREME-ULTRAVIOLET IMAGING SPECTROMETER TO CONFIRM A SEISMOLOGICALLY INFERRED CORONAL TEMPERATURE

    International Nuclear Information System (INIS)

    Marsh, M. S.; Walsh, R. W.

    2009-01-01

    The Extreme-Ultraviolet Imaging Spectrometer on board the HINODE satellite is used to examine the loop system described in Marsh et al. by applying spectroscopic diagnostic methods. A simple isothermal mapping algorithm is applied to determine where the assumption of isothermal plasma may be valid, and the emission measure locii technique is used to determine the temperature profile along the base of the loop system. It is found that, along the base, the loop has a uniform temperature profile with a mean temperature of 0.89 ± 0.09 MK which is in agreement with the temperature determined seismologically in Marsh et al., using observations interpreted as the slow magnetoacoustic mode. The results further strengthen the slow mode interpretation, propagation at a uniform sound speed, and the analysis method applied in Marsh et al. It is found that it is not possible to discriminate between the slow mode phase speed and the sound speed within the precision of the present observations.

  9. Tidal and seasonal variations in calving flux observed with passive seismology

    Science.gov (United States)

    Bartholomaus, T.C.; Larsen, Christopher F.; West, Michael E.; O'Neel, Shad; Pettit, Erin C.; Truffer, Martin

    2015-01-01

    The seismic signatures of calving events, i.e., calving icequakes, offer an opportunity to examine calving variability with greater precision than is available with other methods. Here using observations from Yahtse Glacier, Alaska, we describe methods to detect, locate, and characterize calving icequakes. We combine these icequake records with a coincident, manually generated record of observed calving events to develop and validate a statistical model through which we can infer iceberg sizes from the properties of calving icequakes. We find that the icequake duration is the single most significant predictor of an iceberg's size. We then apply this model to 18 months of seismic recordings and find elevated iceberg calving flux during the summer and fall and a pronounced lull in calving during midwinter. Calving flux is sensitive to semidiurnal tidal stage. Large calving events are tens of percent more likely during falling and low tides than during rising and high tides, consistent with a view that deeper water has a stabilizing influence on glacier termini. Multiple factors affect the occurrence of mechanical fractures that ultimately lead to iceberg calving. At Yahtse Glacier, seismology allows us to demonstrate that variations in the rate of submarine melt are a dominant control on iceberg calving rates at seasonal timescales. On hourly to daily timescales, tidal modulation of the normal stress against the glacier terminus reveals the nonlinear glacier response to changes in the near-terminus stress field.

  10. Conception and test of Echoes, a spectro-imager dedicated to the seismology of Jupiter

    Science.gov (United States)

    Soulat, L.; Schmider, F.-X.; Robbe-Dubois, S.; Appourchaux, T.; Gaulme, P.; Bresson, Y.; Gay, J.; Daban, J.-B.; Gouvret, C.

    2017-11-01

    Echoes is a project of a spaceborne Doppler Spectro-Imager (DSI) which has been proposed as payload to the JUICE mission project selected in the Cosmic Vision program of the European Space Agency (ESA). It is a Fourier transform spectrometer which measures phase shifts in the interference patterns induced by Doppler shifts of spectral lines reflected at the surface of the planet. Dedicated to the seismology of Jupiter, the instrument is designed to analyze the periodic movements induced by internal acoustic modes of the planet. It will allow the knowledge of the internal structure of Jupiter, in particular of the central region, which is essential for the comprehension of the scenario of the giant planets' formation. The optical design is based on a modified Mach-Zehnder interferometer operating in the visible domain and takes carefully into account the sensitivity of the optical path difference to the temperature. The instrument produces simultaneously four images in quadrature which allows the measurement of the phase without being contaminated by the continuum component of the incident light. We expect a noise level less than 1 cm2s-2µHz-1 in the frequency range [0.5 -10] mHz. In this paper, we present the prototype implemented at the Observatoire de la Côte d'Azur (OCA) in collaboration with Institut d'Astrophysique Spatiale (IAS) to study the real performances in laboratory and to demonstrate the capability to reach the required Technology Readiness Level 5.

  11. Facilitate, Collaborate, Educate: the Role of the IRIS Consortium in Supporting National and International Research in Seismology (Invited)

    Science.gov (United States)

    Simpson, D. W.; Beck, S. L.

    2009-12-01

    Over the twenty-five years since its founding in 1984, the IRIS Consortium has contributed in fundamental ways to change the practice and culture of research in seismology in the US and worldwide. From an original founding group of twenty-two U.S. academic institutions, IRIS membership has now grown to 114 U.S. Member Institutions, 20 Educational Affiliates and 103 Foreign Affiliates. With strong support from the National Science Foundation, additional resources provided by other federal agencies, close collaboration with the U.S. Geological Survey and many international partners, the technical resources of the core IRIS programs - the Global Seismographic Network (GSN), the Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL), the Data Management System (DMS) and Education and Outreach - have grown to become a major national and international source of experimental data for research on earthquakes and Earth structure, and a resource to support education and outreach to the public. While the primary operational focus of the Consortium is to develop and maintain facilities for the collection of seismological data for basic research, IRIS has become much more than an instrument facility. It has become a stimulus for collaboration between academic seismological programs and a focus for their interactions with national and international partners. It has helped establish the academic community as a significant contributor to the collection of data and an active participant in global research and monitoring. As a consortium of virtually all of the Earth science research institutions in the US, IRIS has helped coordinate the academic community in the development of new initiatives, such as EarthScope, to strengthen the support for science and argue for the relevance of seismology and its use in hazard mitigation. The early IRIS pioneers had the foresight to carefully define program goals and technical standards for the IRIS facilities that have stood

  12. Dispel4py: An Open-Source Python library for Data-Intensive Seismology

    Science.gov (United States)

    Filgueira, Rosa; Krause, Amrey; Spinuso, Alessandro; Klampanos, Iraklis; Danecek, Peter; Atkinson, Malcolm

    2015-04-01

    Scientific workflows are a necessary tool for many scientific communities as they enable easy composition and execution of applications on computing resources while scientists can focus on their research without being distracted by the computation management. Nowadays, scientific communities (e.g. Seismology) have access to a large variety of computing resources and their computational problems are best addressed using parallel computing technology. However, successful use of these technologies requires a lot of additional machinery whose use is not straightforward for non-experts: different parallel frameworks (MPI, Storm, multiprocessing, etc.) must be used depending on the computing resources (local machines, grids, clouds, clusters) where applications are run. This implies that for achieving the best applications' performance, users usually have to change their codes depending on the features of the platform selected for running them. This work presents dispel4py, a new open-source Python library for describing abstract stream-based workflows for distributed data-intensive applications. Special care has been taken to provide dispel4py with the ability to map abstract workflows to different platforms dynamically at run-time. Currently dispel4py has four mappings: Apache Storm, MPI, multi-threading and sequential. The main goal of dispel4py is to provide an easy-to-use tool to develop and test workflows in local resources by using the sequential mode with a small dataset. Later, once a workflow is ready for long runs, it can be automatically executed on different parallel resources. dispel4py takes care of the underlying mappings by performing an efficient parallelisation. Processing Elements (PE) represent the basic computational activities of any dispel4Py workflow, which can be a seismologic algorithm, or a data transformation process. For creating a dispel4py workflow, users only have to write very few lines of code to describe their PEs and how they are

  13. Insights on the lithospheric structure of the Zagros mountain belt from seismological data analysis

    Science.gov (United States)

    Paul, A.; Kaviani, A.; Vergne, J.; Hatzfeld, D.; Mokhtari, M.

    2003-04-01

    As part of a French-Iranian collaboration, we installed a temporary seismological network across the Zagros for 4.5 months in 2000-2001 to investigate the lithospheric structure of the mountain belt. The network included 65 stations located along a 600-km long line (average spacing of ˜10 km) from the coast of the Persian Gulf to the stable block of Central Iran. A migrated depth cross-section computed from radial receiver functions displays clear P-to-S conversions at the Moho beneath most of the profile. The average Moho depth is 45 to 50 km beneath the folded belt. It deepens rather abruptly beneath the suture zone of the MZT (Main Zagros Thrust) and the Sanandaj-Sirjan (SS) metamorphic zone. The maximum crustal thickness of ˜65 km is reached 50 km NE of the surface trace of the MZT. The region of over-thickened crust is shifted to the NE with respect to the areas of highest elevations and the strongest negative Bouguer anomaly. To the NE, the crust of the block of Central Iran is 40-km thick on average. Two patches of Ps converted energy can be seen below the Moho in the northern half of the transect that cannot be attributed to multiple reflections. Teleseismic P residual travel time curves display lateral variations as large as 1.5 s with both long (faster arrivals in the SW than in the NE) and short-scale variations (in the MZT region). They were inverted for variations of P wave velocity with the ACH technique. The crustal layer exhibits rather strong lateral variations of Vp with lower velocities under the MZT and the Urumieh-Dokhtar magmatic assemblage, and faster velocities under the SS zone. In the mantle, a clear difference appears between the faster P wave velocities of the Arabian craton and the relatively lower velocities of the mantle of Central Iran.

  14. QuakeML: Status of the XML-based Seismological Data Exchange Format

    Science.gov (United States)

    Euchner, Fabian; Schorlemmer, Danijel; Kästli, Philipp; Quakeml Working Group

    2010-05-01

    QuakeML is an XML-based data exchange standard for seismology that is in its fourth year of active community-driven development. The current release (version 1.2) is based on a public Request for Comments process that included contributions from ETH, GFZ, USC, SCEC, USGS, IRIS DMC, EMSC, ORFEUS, GNS, ZAMG, BRGM, Nanometrics, and ISTI. QuakeML has mainly been funded through the EC FP6 infrastructure project NERIES, in which it was endorsed as the preferred data exchange format. Currently, QuakeML services are being installed at several institutions around the globe, including EMSC, ORFEUS, ETH, Geoazur (Europe), NEIC, ANSS, SCEC/SCSN (USA), and GNS Science (New Zealand). Some of these institutions already provide QuakeML earthquake catalog web services. Several implementations of the QuakeML data model have been made. QuakePy, an open-source Python-based seismicity analysis toolkit using the QuakeML data model, is being developed at ETH. QuakePy is part of the software stack used in the Collaboratory for the Study of Earthquake Predictability (CSEP) testing center installations, developed by SCEC. Furthermore, the QuakeML data model is part of the SeisComP3 package from GFZ Potsdam. QuakeML is designed as an umbrella schema under which several sub-packages are collected. The present scope of QuakeML 1.2 covers a basic description of seismic events including picks, arrivals, amplitudes, magnitudes, origins, focal mechanisms, and moment tensors. Work on additional packages (macroseismic information, seismic inventory, and resource metadata) has been started, but is at an early stage. Contributions from the community that help to widen the thematic coverage of QuakeML are highly welcome. Online resources: http://www.quakeml.org, http://www.quakepy.org

  15. Enhancing Outreach using Social Networks at the National Seismological Network of Costa Rica

    Science.gov (United States)

    Linkimer, L.; Lücke, O. H.

    2014-12-01

    Costa Rica has a very high seismicity rate and geological processes are part of everyday life. Traditionally, information about these processes has been provided by conventional mass media (television and radio). However, due to the new trends in information flow a new approach towards Science Education is necessary for transmitting knowledge from scientific research for the general public in Costa Rica. Since 1973, the National Seismological Network of Costa Rica (RSN: UCR-ICE) studies the seismicity and volcanic activity in the country. In this study, we describe the different channels to report earthquake information that the RSN is currently using: email, social networks, and a website, as well as the development of a smartphone application. Since the RSN started actively participating in Social Networks, an increase in awareness in the general public has been noticed particularly regarding felt earthquakes. Based on this trend, we have focused on enhancing public outreach through Social Media. We analyze the demographics and geographic distribution of the RSN Facebook Page, the growth of followers, and the significance of their feedback for reporting intensity data. We observe that certain regions of the country have more Facebook activity, although those regions are not the most populated nor have a high Internet connectivity index. We interpret this pattern as the result of a higher awareness to geological hazards in those specific areas. We noticed that the growth of RSN users on Facebook has a strong correlation with the seismic events as opposed to Twitter that displays a steady growth with no clear correlations with specific seismic events. We see the Social Networks as opportunities to engage non-science audiences and encourage the population to participate in reporting seismic observations, thus providing intensity data. With the increasing access to Internet from mobile phones in Costa Rica, we see this approach to science education as an opportunity

  16. Seismological studies carried out by the CEA in connection with the safety of nuclear sites

    International Nuclear Information System (INIS)

    Barbreau, A.; Ferrieux, H.; Mohammadioun, B.

    1975-01-01

    In order to evaluate the seismic risk at nuclear sites, the Department of Nuclear Safety of the French Atomic Energy Commission (CEA) has been conducting a programme of seismological studies for several years past. This programme is aimed at acquiring a better knowledge of seismic phenomena, in particular the spectral distribution of the energy of earthquakes, considered to be the only correct approach to the problem of earthquake protection, as well as a better knowledge of the seismic activity of the areas surrounding nuclear sites. The authors propose defining the design spectrum of the site on the basis of the probable energy at the source, the distance from the epicentre and the transfer function of the geological formations. The need - for the purpose of defining this spectrum - to acquire data on the characteristics of French earthquakes and on regional seismicity led the Department of Nuclear Safety to set up a network of seismic stations. It now has an observatory at the Cadarache Nuclear Research Centre and mobile stations with automatic magnetic recording for studying aftershock sequences and the activity of faults in the vicinity of nuclear sites, and for making the measurements necessary to calculate the transfer functions. With this equipment it was possible to record six aftershocks of the Oleron earthquake on 7 September 1972 close to the epicentre, and to calculate the spectra therefrom. The latter contained a lot of high frequencies, which is in agreement with the data obtained from other sources for earthquakes of low energy. The synthetic spectra calculated on the basis of one magnitude and one distance are in good agreement with the spectra obtained experimentally

  17. Seismological investigation of September 09 2016, North Korea underground nuclear test

    Directory of Open Access Journals (Sweden)

    H. Gaber

    2017-12-01

    Full Text Available On Sep. 9, 2016, a seismic event of mb 5.3 took place in North Korea. This event was reported as a nuclear test. In this study, we applied a number of discriminant techniques that facilitate the ability to distinguish between explosions and earthquakes on the Korean Peninsula. The differences between explosions and earthquakes are due to variation in source dimension, epicenter depth and source mechanism, or a collection of them. There are many seismological differences between nuclear explosions and earthquakes, but not all of them are detectable at large distances or are appropriate to each earthquake and explosion. The discrimination methods used in the current study include the seismic source location, source depth, the differences in the frequency contents, complexity versus spectral ratio and Ms-mb differences for both earthquakes and explosions. Sep. 9, 2016, event is located in the region of North Korea nuclear test site at a zero depth, which is likely to be a nuclear explosion. Comparison between the P wave spectra of the nuclear test and the Sep. 8, 2000, North Korea earthquake, mb 4.9 shows that the spectrum of both events is nearly the same. The results of applying the theoretical model of Brune to P wave spectra of both explosion and earthquake show that the explosion manifests larger corner frequency than the earthquake, reflecting the nature of the different sources. The complexity and spectral ratio were also calculated from the waveform data recorded at a number of stations in order to investigate the relation between them. The observed classification percentage of this method is about 81%. Finally, the mb:Ms method is also investigated. We calculate mb and Ms for the Sep. 9, 2016, explosion and compare the result with the mb: Ms chart obtained from the previous studies. This method is working well with the explosion. Keywords: Discrimination, Seismic source location, Brune model, Spectral parameters, Complexity method, Mb: Ms

  18. High-rate multi-GNSS: what does it mean to seismology?

    Science.gov (United States)

    Geng, J.

    2017-12-01

    GNSS precise point positioning (PPP) is capable of measuring centimeter-level positions epoch by epoch at a single station, and is thus treasured in tsunami/earthquake early warning where static displacements in the near field are critical to rapidly and reliably determining the magnitude of destructive events. However, most operational real-time PPP systems at present rely on only GPS data. The deficiency of such systems is that the high reliability and availability of precise displacements cannot be maintained continuously in real time, which is however a crucial requirement for disaster resistance and response. Multi-GNSS, including GLONASS, BeiDou, Galileo and QZSS other than only GPS, can be a solution to this problem because much more satellites per epoch (e.g. 30-40) will be available. In this case, positioning failure due to data loss or blunders can be minimized, and on the other hand, positioning initializations can be accelerated to a great extent since the satellite geometry for each epoch will be enhanced enormously. We established a prototype real-time multi-GNSS PPP service based on Asia-Pacific real-time network which can collect and stream high-rate data from all five navigation systems above. We estimated high-rate satellite clock corrections and enabled undifferenced ambiguity fixing for multi-GNSS, which therefore ensures high availability and reliability of precise displacement estimates in contrast to GPS-only systems. We will report how we can benefit from multi-GNSS for seismology, especially the noise characteristics of high-rate and sub-daily displacements. We will also use storm surge loading events to demonstrate the contribution of multi-GNSS to sub-daily transient signals.

  19. Young solar-type stars evolution: the lithium and seismology contributions

    International Nuclear Information System (INIS)

    Piau, Laurent Eric

    2001-01-01

    This PhD thesis is devoted to young low-mass stars. We modeled many of them since their formation until the solar age covering the range between 0.65 and 1.4 solar masses and metallicity values ranging from -0.1 to 0.1 dex. The theoretical computations are related to observations in nearby open-clusters: Hyades, Pleiades... This comparison demonstrates that the lithium evolution is still poorly understood in such stars. In stellar interiors, this nuclide is destroyed by nuclear processes at low temperatures. Its surface abundance evolution traduces mixing phenomena between surface and deeper layers and therefore allows a direct insight into stellar structure and evolution. Both of which depend on microscopic and macroscopic physical phenomena whose effects we systematically examine. As regards microphysics we mainly concentrate upon changes in metallicity, in distribution among metals and their consequences on stellar opacity. We also address atmospheric models while the star still lies close to its Hayashi track. Accretion and convective parameters are the macroscopic phenomena we address during pre-main sequence. The rotational effects are considered along the entire evolution including the much realistic rotation laws. The last part of this PhD thesis makes use of seismology. Today this Discipline allows direct probing of the solar internal structure and motions. Its future application in the realm of stars will substantially improve their understanding. We derive here some relevant seismic variables for the understanding of stellar evolution. Then we show how this powerful tool permits to determine fundamental stellar parameters such as the mass or the helium fraction. (author) [fr

  20. Using seismology to raise science awareness in kindergarten and elementary levels, with the help of high school students

    Science.gov (United States)

    Rocha, F. L.; Silveira, G. M.; Moreira, G.; Afonso, I. P.; Maciel, B. A. P. C.; Melo, M. O.; Neto, R. P.; Gonçalves, M.; Marques, G.; Hartmann, R. P.

    2014-12-01

    Teaching students, aged from 4 up to 18 years old, is a challenging task. It continuously implies new strategies and new subjects adapted to all of them. This is even more evident, when we have to teach natural-hazards scientific aspects and safe attitudes toward risk. We often see that most of the high-school students (16 -18 years old) are not motivated for extra-curricular activities implying science and/or behaviours changes. But, they have a very positive response when we give them some responsibility. On top of that, we also realised that young children are quite receptive to the involvement of older students in the school environment Taking this into consideration, our project use the k12 students to prepare scientific activities and subjects, based in questions, which they need to answer themselves. The students need to answer those questions and, only then, adapt and teach the right answers to the different school-levels. With this approach, we challenged the students to solve three questions: How to use a SEP seismometer at school, and its data? How to set up a shaking table? How to introduce waves and vibrations contents to all ages of students? During the project they developed many science skills, and worked in straight cooperation with teachers, the parents association and the seismology research group at Instituto Dom Luíz. As a result, it was possible to reach all school students with the help of the k-12 ones. This is an outcome of the project W-Shake, a Parents-in-Science Initiative to promote the study of seismology and related subjects. This project, supported by the Portuguese "Ciência Viva" program, results from a direct cooperation between the parents association, science school-teachers and the seismology research group at Instituto Dom Luíz.

  1. Eagle Pass Jr. High Seismology Team: Strategies for Engaging Middle School "At-Risk" Students in Authentic Research

    Science.gov (United States)

    Brunt, M. R.; Ellins, K. K.; Frohlich, C. A.

    2011-12-01

    In 2008, during my participation in the NSF-sponsored Texas Earth & Space Science (TXESS) Revolution professional development program, I was awarded an AS-1 seismograph through IRIS's Seismographs in Schools Program. This program serves to create an international educational seismic network that allows teachers across the country and around the world to share seismic data in real-time using online tools, classroom activities, and technical support documents for seismic instruments. Soon after receiving my AS-1, I founded and began sponsoring the Eagle Pass Jr. High Seismology Team which consists of selected 7th and 8th grade students. Eagle Pass Jr. High is a Title 1 school that serves a predominantly "at-risk" Hispanic population. We meet after school once a week to learn about earthquakes, seismic waves, analyze recorded seismic event data using computer software programming, and correspond with other students from schools around the country. This team approach has been well received by fellow TXESS Revolution teachers with AS-1 seismographs and will be implemented by David Boyd, STEM coordinator for Williams Preparatory Academy in Dallas, Texas this fall 2011. All earthquakes recorded by our seismograph station (EPTX), which has remained online and actively recording seismic data since 2008, are catalogued and then plotted on a large world map displayed on my classroom wall. A real-time seismogram image updates every five minutes and along with all earthquakes recorded since installation can be viewed on our webpage http://www.iris.edu/hq/ssn/schools/view/eptx. During the 2010-2011 school year, my seismology team and I participated in an earthquake research study led by Dr. Cliff Frohlich at the Institute for Geophysics. The study examined seismograms and felt reports for the 25 April 2010 Alice, Texas, earthquake, in order to investigate its possible connection to oil and gas production in the Stratton oil and gas field. A research paper detailing our findings

  2. ASDF: A New Adaptable Data Format for Seismology Suitable for Large-Scale Workflows

    Science.gov (United States)

    Krischer, L.; Smith, J. A.; Spinuso, A.; Tromp, J.

    2014-12-01

    Increases in the amounts of available data as well as computational power opens the possibility to tackle ever larger and more complex problems. This comes with a slew of new problems, two of which are the need for a more efficient use of available resources and a sensible organization and storage of the data. Both need to be satisfied in order to properly scale a problem and both are frequent bottlenecks in large seismic inversions using ambient noise or more traditional techniques.We present recent developments and ideas regarding a new data format, named ASDF (Adaptable Seismic Data Format), for all branches of seismology aiding with the aforementioned problems. The key idea is to store all information necessary to fully understand a set of data in a single file. This enables the construction of self-explaining and exchangeable data sets facilitating collaboration on large-scale problems. We incorporate the existing metadata standards FDSN StationXML and QuakeML together with waveform and auxiliary data into a common container based on the HDF5 standard. A further critical component of the format is the storage of provenance information as an extension of W3C PROV, meaning information about the history of the data, assisting with the general problem of reproducibility.Applications of the proposed new format are numerous. In the context of seismic tomography it enables the full description and storage of synthetic waveforms including information about the used model, the solver, the parameters, and other variables that influenced the final waveforms. Furthermore, intermediate products like adjoint sources, cross correlations, and receiver functions can be described and most importantly exchanged with others.Usability and tool support is crucial for any new format to gain acceptance and we additionally present a fully functional implementation of this format based on Python and ObsPy. It offers a convenient way to discover and analyze data sets as well as making

  3. Applications of seismic spatial wavefield gradient and rotation data in exploration seismology

    Science.gov (United States)

    Schmelzbach, C.; Van Renterghem, C.; Sollberger, D.; Häusler, M.; Robertsson, J. O. A.

    2017-12-01

    Seismic spatial wavefield gradient and rotation data have the potential to open up new ways to address long-standing problems in land-seismic exploration such as identifying and separating P-, S-, and surface waves. Gradient-based acquisition and processing techniques could enable replacing large arrays of densely spaced receivers by sparse spatially-compact receiver layouts or even one single multicomponent station with dedicated instruments (e.g., rotational seismometers). Such approaches to maximize the information content of single-station recordings are also of significant interest for seismic measurements at sites with limited access such as boreholes, the sea bottom, and extraterrestrial seismology. Arrays of conventional three-component (3C) geophones enable measuring not only the particle velocity in three dimensions but also estimating their spatial gradients. Because the free-surface condition allows to express vertical derivatives in terms of horizontal derivatives, the full gradient tensor and, hence, curl and divergence of the wavefield can be computed. In total, three particle velocity components, three rotational components, and divergence, result seven-component (7C) seismic data. Combined particle velocity and gradient data can be used to isolate the incident P- or S-waves at the land surface or the sea bottom using filtering techniques based on the elastodynamic representation theorem. Alternatively, as only S-waves exhibit rotational motion, rotational measurements can directly be used to identify S-waves. We discuss the derivations of the gradient-based filters as well as their application to synthetic and field data, demonstrating that rotational data can be of particular interest to S-wave reflection and P-to-S-wave conversion imaging. The concept of array-derived gradient estimation can be extended to source arrays as well. Therefore, source arrays allow us to emulate rotational (curl) and dilatational (divergence) sources. Combined with 7C

  4. Engaging High School Science Teachers in Field-Based Seismology Research: Opportunities and Challenges

    Science.gov (United States)

    Long, M. D.

    2015-12-01

    Research experiences for secondary school science teachers have been shown to improve their students' test scores, and there is a substantial body of literature about the effectiveness of RET (Research Experience for Teachers) or SWEPT (Scientific Work Experience Programs for Teachers) programs. RET programs enjoy substantial support, and several opportunities for science teachers to engage in research currently exist. However, there are barriers to teacher participation in research projects; for example, laboratory-based projects can be time consuming and require extensive training before a participant can meaningfully engage in scientific inquiry. Field-based projects can be an effective avenue for involving teachers in research; at its best, earth science field work is a fun, highly immersive experience that meaningfully contributes to scientific research projects, and can provide a payoff that is out of proportion to a relatively small time commitment. In particular, broadband seismology deployments provide an excellent opportunity to provide teachers with field-based research experience. Such deployments are labor-intensive and require large teams, with field tasks that vary from digging holes and pouring concrete to constructing and configuring electronics systems and leveling and orienting seismometers. A recently established pilot program, known as FEST (Field Experiences for Science Teachers) is experimenting with providing one week of summer field experience for high school earth science teachers in Connecticut. Here I report on results and challenges from the first year of the program, which is funded by the NSF-CAREER program and is being run in conjunction with a temporary deployment of 15 seismometers in Connecticut, known as SEISConn (Seismic Experiment for Imaging Structure beneath Connecticut). A small group of teachers participated in a week of field work in August 2015 to deploy seismometers in northern CT; this experience followed a visit of the

  5. Real Time Data for Seismology at the IRIS Data Management Center, AN Nsf-Sponsored Facility

    Science.gov (United States)

    Benson, R. B.; Ahern, T. K.; Trabant, C.; Weertman, B. R.; Casey, R.; Stromme, S.; Karstens, R.

    2012-12-01

    When IRIS was incorporated in 1984, it committed to provide long-term support for the science of seismology. It first upgraded analog networks by installing observatory grade digital seismic recording equipment (by constructing the Global Seismic Network to upgrade the World Wide Standardized Seismographic Network) that became the backbone of the International Federation of Digital Seismic Networks (FDSN), and in 1990 constructed a state-of-the-art data center that would allow free and open access to data to everyone. For the first decade, IRIS leveraged a complicated system of telemetry which laid the foundation for delivering (relatively) high rate and continuous seismic time series data to the IRIS Data Management Center, which was designed to accept data that arrived with highly variable latencies and on many media formats. This meant that science had to often wait until data became complete, which at the time was primarily related to studying earthquakes or similar events. During the 1990's, numerous incremental but small improvements were made to get data into the hands of users with less latency, leveraging dialup, satellite telemetry, and a variety of Internet protocols. But beginning in 2000, the IRIS Data Management Center began the process of accumulating data comprehensively in real time. It was first justified because it eliminated the time-consuming transcription and manual data handling on various media formats, like magnetic tapes, CD's and DVD's. However, the switch to real-time telemetry proved to be a major improvement technologically because it not only simplified data transfer, it opened access to a large volume of previously inaccessible data (local resource limitations), and many networks began willingly providing their geophysical data to the broad research community. It also enabled researchers the ability to process data in different and streamlined ways, by incorporating data directly into workflows and processing packages. Any network on

  6. AlpArray - technical strategies for large-scale European co-operation in broadband seismology

    Science.gov (United States)

    Brisbourne, A.; Clinton, J.; Hetenyi, G.; Pequegnat, C.; Wilde-Piorko, M.; Villasenor, A.; Comelli, P.; AlpArray Working Group

    2012-04-01

    AlpArray is a new initiative to study the greater Alpine area with a large-scale broadband seismological network. The interested parties (currently 32 institutes in 12 countries) plan to combine their existing infrastructures into an all-out transnational effort that includes data acquisition, processing, imaging and interpretation. The experiment will encompass the greater Alpine area, from the Black Forest in the north to the Northern Apennines in the south and from the Pannonian Basin in the east to the French Massif Central in the west. We aim to cover this region with high-quality broadband seismometers by combining the ~400 existing permanent stations with an additional 400+ instruments from mobile pools. In this way, we plan to achieve homogeneous and high resolution coverage while also deploying densely spaced stations along swaths across key parts of the Alpine chain. These efforts on land will be combined with deployments of ocean bottom seismometers in the Mediterranean Sea. Significant progress has already been made in outlining the scientific goals and funding strategy. A brief overview of these aspects of the initiative will be presented here. However, we will concentrate on the technical aspects: How efficient large-scale integration of existing infrastructures can be achieved. Existing permanent station coverage within the greater Alpine area has been collated and assessed for data availability, allowing strategies to be developed for network densification to ensure a robust backbone network: An anticipated deployment strategy has been drawn up to optimise array coverage and data quality. The augmented backbone network will be supplemented by more densely spaced temporary arrays targeting more specific scientific questions. For these temporary arrays, a strategy document has been produced to outline standards for station installation, data acquisition, processing, archival and dissemination. All these operations are of course vital. However, data

  7. Significant breakthroughs in monitoring networks of the volcanological and seismological French observatories

    Science.gov (United States)

    lemarchand, A.; Francois, B.; Bouin, M.; Brenguier, F.; Clouard, V.; Di Muro, A.; Ferrazzini, V.; Shapiro, N.; Staudacher, T.; Kowalski, P.; Agrinier, P.

    2013-12-01

    Others authors: S. Tait (1), D. Amorese (4,1), JB de Chabalier (1), A. Anglade (4,1), P. Kowalski (5,1),the teams in the IPGP Volcanological and Seismological observatories In the last few years, French West Indies observatories, in collaboration with the Seismic Research Center (University of West Indies-Trinidad), have modernized the Lesser Antilles Arc seismic and deformation monitoring network. 16 new permanent stations have been installed to strengthen and expand its detection capabilities. The global network of the IPGP-SRC consortium is now composed of 21 modernized stations, all equipped with broadband seismometers, strong motion sensors, GNSS sensors and satellite communication for real-time data transfer to the observatories of Trinidad (SRC), Guadeloupe (OVSG), Martinique (OVSM). To improve the sensitivity and reduce ambient noise, special efforts were made to enhance the design of the seismic vault and the original Stuttgart shielding (D. Kurrle R. Widmer-Schnidrig, 2005) of the broadband seismometers (240 and 120 sec). This renewed network feeds the Caribbean Tsunami Warning System supported by UNESCO and establishes a monitoring tool that produces high quality data for studying subduction and volcanism interactions in the Lesser Antilles arc. Since 2010, the UnderVolc research program has been an opportunity to reinforce the existing volcanic seismic network of Piton de la Fournaise on La Réunion Island (Indian Ocean). 20 broadband seismometers, 20 short-period sensors, and 26 GNSS receivers now cover the volcano. The program successfully developed many new data treatment tools. They have proven to be well-adapted for monitoring volcanic activity such as the tracking of seismic velocity changes inferred from seismic noise, or the injection of dike and the resulting deformations. This upgrade has now established the monitoring network of La Réunion hot spot to high quality standards which will foster the scientific attractiveness of OVPF-IPGP. During

  8. Autonomous geodynamics of the Pamir-Tien Shan junction zone from seismology data

    Science.gov (United States)

    Lukk, A. A.; Shevchenko, V. I.; Leonova, V. G.

    2015-11-01

    The geodynamics of the Tajik Depression, the junction zone of the Pamirs and Tien Shan, is typically considered in the context of plate tectonic concept, which implies intense subhorizontal compression of the zone resulting from the subduction of the Indian and Eurasian lithospheric plates. This convergence has been reliably confirmed by the GPS measurements. However, the joint analysis of the geological structure, seismicity, and geodimeter measurements conducted during a few years at the Garm geodynamical testing site of the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, demonstrates a widening of the Tajik Depression instead of its shortening, as should be expected from the subhorizontal compression predominant in the present-day stress-state of this region. This conclusion, together with the data from the other regions, suggests that, along with the plate tectonic mechanisms, there are also other, local, autonomous drivers that contribute to the tectogenesis of this region. Besides, the probable existence of these autonomous sources within the Tajik Depression directly follows from the seismology data. Among them is the crustal spreading within the depression suggested by the seismotectonic displacements in the focal mechanisms of the earthquakes. These displacements are directed in different azimuths off the axial's most subsided part of the depression at a depth of 20-30 km. Above this region the distribution of seismotectonic deformations (STD) is chaotic. This pattern of deformation is barely accounted for by a simple model of subhorizontal compression of the Earth's crust in the region. In our opinion, these features of the seismotectonic deformation in the crust within the studied part of the Tajik Depression is probably associated with the gain in the volume of the rocks due to the inflow of the additional material, which is supplied from the bottom crust or upper mantle by the deep fluids. This increase in the rock volume

  9. Continuous catchment-scale monitoring of geomorphic processes with a 2-D seismological array

    Science.gov (United States)

    Burtin, A.; Hovius, N.; Milodowski, D.; Chen, Y.-G.; Wu, Y.-M.; Lin, C.-W.; Chen, H.

    2012-04-01

    highlights the major interest of a seismic monitoring since it allows a detailed spatial and temporal survey of events that classic approaches are not able to observe. In the future, dense two dimensional seismological arrays will assess in real-time the landscape dynamics of an entire catchment, tracking sediments from slopes to rivers.

  10. Diploma in Seismology for High-School Teachers in Mexico Through an Open-Source Learning Plataform

    Science.gov (United States)

    Perez-Campos, X.; Bello, D.; Dominguez, J.; Pérez, J.; Cruz, J. L.; Navarro Estrada, F.; Mendoza Carvajal, A. D. J.

    2017-12-01

    The high school Physics programs in Mexico do not consider the immediate application of the concepts learned by the students. According to some pedagogical theories many of the acquired knowledge are assimilated when experimenting, expressing, interacting and developing projects. It is in high school when young people are exploring and looking for experiences to decide the area in which they want to focus their studies. The areas of science and engineering are chosen, mainly motivated by technology and outer space. There is little interest in Earth science, reflected by the number of students in those areas. This may be due mainly to the lack of exposure and examples at the high school level. With this in mind, we are working on a project that seeks, through the preparation of teachers of this level, to bring their students to seismology and awaken in them their curiosity in issues related to it. Based on the above, and taking as examples the successful programs "Seismographs in Schools" from IRIS and "Geoscience Information For Teachers" from EGU, the Mexican National Seismological Service has launched a project that contemplates three stages. The first one consists of the design and delivery of a diploma addressed to high school teachers. The second contemplates the installation of short-period seismographs in each of the participating faculty facilities. Finally, the third one involves the active participation of teachers and their students in research projects based on the data collected in the instruments installed in their schools. This work presents the first phase. The diploma has been designed to offer teachers, in 170 hours, an introduction to topics related to seismology and to provide them with tools and examples that they can share with their students in their classroom. It is offered both online through Moodle, an open-source learning plataform, and in 12 classroom sessions. The first class started on June 2017 and will finish on November 2017. We

  11. Severity Classification of a Seismic Event based on the Magnitude-Distance Ratio Using Only One Seismological Station

    Directory of Open Access Journals (Sweden)

    Luis Hernán Ochoa Gutiérrez

    2014-07-01

    Full Text Available Seismic event characterization is often accomplished using algorithms based only on information received at seismological stations located closest to the particular event, while ignoring historical data received at those stations. These historical data are stored and unseen at this stage. This characterization process can delay the emergency response, costing valuable time in the mitigation of the adverse effects on the affected population. Seismological stations have recorded data during many events that have been characterized by classical methods, and these data can be used as previous "knowledge" to train such stations to recognize patterns. This knowledge can be used to make faster characterizations using only one three-component broadband station by applying bio-inspired algorithms or recently developed stochastic methods, such as kernel methods. We trained a Support Vector Machine (SVM algorithm with seismograph data recorded by INGEOMINAS's National Seismological Network at a three-component station located near Bogota, Colombia. As input model descriptors, we used the following: (1 the integral of the Fourier transform/power spectrum for each component, divided into 7 windows of 2 seconds and beginning at the P onset time, and (2 the ratio between the calculated logarithm of magnitude (Mb and epicentral distance. We used 986 events with magnitudes greater than 3 recorded from late 2003 to 2008. The algorithm classifies events with magnitude-distance ratios (a measure of the severity of possible damage caused by an earthquake greater than a background value. This value can be used to estimate the magnitude based on a known epicentral distance, which is calculated from the difference between P and S onset times. This rapid (< 20 seconds magnitude estimate can be used for rapid response strategies. The results obtained in this work confirm that many hypocentral parameters and a rapid location of a seismic event can be obtained using a few

  12. Combining Space Geodesy, Seismology, and Geochemistry for Monitoring Verification and Accounting of CO2 in Sequestration Sites

    Energy Technology Data Exchange (ETDEWEB)

    Swart, Peter K. [Univ. of Miami, Key Biscayne, FL (United States); Dixon, Tim [Univ. of South Florida, Tampa, FL (United States)

    2014-09-30

    A series of surface geophysical and geochemical techniques are tested in order to demonstrate and validate low cost approaches for Monitoring, Verification and Accounting (MVA) of the integrity of deep reservoirs for CO2 storage. These techniques are (i) surface deformation by GPS; ii) surface deformation by InSAR; iii) passive source seismology via broad band seismometers; and iv) soil gas monitoring with a cavity ring down spectrometer for measurement of CO2 concentration and carbon isotope ratio. The techniques were tested at an active EOR (Enhanced Oil Recovery) site in Texas. Each approach has demonstrated utility. Assuming Carbon Capture, Utilization and Storage (CCUS) activities become operational in the future, these techniques can be used to augment more expensive down-hole techniques.

  13. QuakeML: Recent Development and First Applications of the Community-Created Seismological Data Exchange Standard

    Science.gov (United States)

    Euchner, F.; Schorlemmer, D.; Kästli, P.; Quakeml Group, T

    2008-12-01

    QuakeML is an XML-based exchange format for seismological data which is being developed using a community-driven approach. It covers basic event description, including picks, arrivals, amplitudes, magnitudes, origins, focal mechanisms, and moment tensors. Contributions have been made from ETH, GFZ, USC, SCEC, USGS, IRIS DMC, EMSC, ORFEUS, GNS, ZAMG, BRGM, and ISTI. The current release (Version 1.1, Proposed Recommendation) reflects the results of a public Request for Comments process which has been documented online at http://quakeml.org/RFC_BED_1.0. QuakeML has recently been adopted as a distribution format for earthquake catalogs by GNS Science, New Zealand, and the European-Mediterranean Seismological Centre (EMSC). These institutions provide prototype QuakeML web services. Furthermore, integration of the QuakeML data model in the CSEP (Collaboratory for the Study of Earthquake Predictability, http://www.cseptesting.org) testing center software developed by SCEC is under way. QuakePy is a Python- based seismicity analysis toolkit which is based on the QuakeML data model. Recently, QuakePy has been used to implement the PMC method for calculating network recording completeness (Schorlemmer and Woessner 2008, in press). Completeness results for seismic networks in Southern California and Japan can be retrieved through the CompletenessWeb (http://completenessweb.org). Future QuakeML development will include an extension for macroseismic information. Furthermore, development on seismic inventory information, resource identifiers, and resource metadata is under way. Online resources: http://www.quakeml.org, http://www.quakepy.org

  14. VERCE: a productive e-Infrastructure and e-Science environment for data-intensive seismology research

    Science.gov (United States)

    Vilotte, Jean-Pierre; Atkinson, Malcolm; Carpené, Michele; Casarotti, Emanuele; Frank, Anton; Igel, Heiner; Rietbrock, Andreas; Schwichtenberg, Horst; Spinuso, Alessandro

    2016-04-01

    Seismology pioneers global and open-data access -- with internationally approved data, metadata and exchange standards facilitated worldwide by the Federation of Digital Seismic Networks (FDSN) and in Europe the European Integrated Data Archives (EIDA). The growing wealth of data generated by dense observation and monitoring systems and recent advances in seismic wave simulation capabilities induces a change in paradigm. Data-intensive seismology research requires a new holistic approach combining scalable high-performance wave simulation codes and statistical data analysis methods, and integrating distributed data and computing resources. The European E-Infrastructure project "Virtual Earthquake and seismology Research Community e-science environment in Europe" (VERCE) pioneers the federation of autonomous organisations providing data and computing resources, together with a comprehensive, integrated and operational virtual research environment (VRE) and E-infrastructure devoted to the full path of data use in a research-driven context. VERCE delivers to a broad base of seismology researchers in Europe easily used high-performance full waveform simulations and misfit calculations, together with a data-intensive framework for the collaborative development of innovative statistical data analysis methods, all of which were previously only accessible to a small number of well-resourced groups. It balances flexibility with new integrated capabilities to provide a fluent path from research innovation to production. As such, VERCE is a major contribution to the implementation phase of the ``European Plate Observatory System'' (EPOS), the ESFRI initiative of the solid-Earth community. The VRE meets a range of seismic research needs by eliminating chores and technical difficulties to allow users to focus on their research questions. It empowers researchers to harvest the new opportunities provided by well-established and mature high-performance wave simulation codes of the

  15. Active tectonics in the Mygdonia basin (northern Greece): a combined seismological and remote-sensed geomorphology approach

    Science.gov (United States)

    Gkarlaouni, Charikleia; Andreani, Louis; Pennos, Chris; Gloaguen, Richard; Papadimitriou, Eleftheria; Kilias, Adamantios; Michail, Maria

    2014-05-01

    In Greek mainland, active extensional deformation resulted in the development of numerous seismogenic E- to SE-trending basins. The Mygdonia graben located in central Macedonia produced major historical earthquakes and poses a serious threat to the neighbouring city of Thessaloniki. Our aim is to determine which active seismic sources have the potential to generate strong events. Active tectonics shape the landscape, control the evolution of the fluvial network and cause the occurrence of strong and frequent earthquakes generated by fault populations. Thus, our approach combined both seismology and remote-sensed geomorphology. Seismological investigation and more especially relocation analysis was performed for recent seismicity in the area (2000-2012). Low magnitude earthquakes not exceeding 4.8 constitute the seismicity pattern for this period. Accurately determined focal parameters indicate that seismicity is not only localized along major fault zones. Smaller faults seem also to be activated. Temporal and spatial investigation show that seismicity is clustered and seismic bursts often migrate to adjacent faults. The hypocentral distribution of precisely determined microearthquake foci reveals the existence of high-angle (> 60º) normal faults dipping both south and north. This is consistent with fault plane solutions of stronger earthquakes. The largest amount of earthquakes is generated along the NW-SE sub-basin bounded from "Assiros-Analipsi" and "Lagina" fault zone, as well as in "Sochos" fault in the north which dips with approximately 70º-80º to the south. All these structures played an important role in the seismotectonic evolution of the area. We used geomorphic indices in order to analyse the landscapes of the Mygdonia region. Geomorphic indices were derived from DEM and computed using MATLAB scripts. We classified the landscapes according to their erosional stages using hypsometric integral and surface roughness. Both indices suggest stronger erosion

  16. Data Logging and Data Modelling: Using seismology and seismic data to create challenge in the academic classroom.

    Science.gov (United States)

    Neighbour, Gordon

    2013-04-01

    In 2012 Computing and Information Technology was disapplied from the English National Curriculum and therefore no longer has a compulsory programme of study. Data logging and data modelling are still essential components of the curriculum in the Computing and Information Technology classroom. Once the students have mastered the basics of both spreadsheet and information handling software they need to be further challenged. All too often the data used with relation to data-logging and data-handling is not realistic enough to really challenge very able students. However, using data from seismology allows students to manipulate "real" data and enhances their experience of geo-science, developing their skills and then allowing them to build on this work in both the science and geography classroom. This new scheme of work "Seismology at School" has allowed the students to work and develop skills beyond those normally expected for their age group and has allowed them to better appreciate their learning experience of "Natural Hazards" in the science and geography classroom in later years. The students undertake research to help them develop their understanding of earthquakes. This includes using materials from other nations within the European Economic Area, to also develop and challenge their use of Modern Foreign Languages. They are then challenged to create their own seismometers using simple kits and 'free' software - this "problem-solving" approach to their work is designed to enhance team-work and to extend the challenge they experience in the classroom. The students are then are asked to manipulate a "real" set of data using international earthquake data from the most recent whole year. This allows the students to make use of many of the analytical and statistical functions of both spreadsheet software and information handling software in a meaningful way. The students will need to have developed a hypothesis which their work should have provided either validation

  17. A high-damping magnetorheological elastomer with bi-directional magnetic-control modulus for potential application in seismology

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Miao, E-mail: yumiao@cqu.edu.cn; Qi, Song; Fu, Jie; Zhu, Mi [Key Lab for Optoelectronic Technology and Systems, Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2015-09-14

    A high-damping magnetorheological elastomer (MRE) with bi-directional magnetic-control modulus is developed. This MRE was synthesized by filling NdFeB particles into polyurethane (PU)/ epoxy (EP) interpenetrating network (IPN) structure. The anisotropic samples were prepared in a permanent magnetic field and magnetized in an electromagnetic field of 1 T. Dynamic mechanical responses of the MRE to applied magnetic fields are investigated through magneto-rheometer, and morphology of MREs is observed via scanning electron microscope (SEM). Test result indicates that when the test field orientation is parallel to that of the sample's magnetization, the shear modulus of sample increases. On the other hand, when the orientation is opposite to that of the sample's magnetization, shear modulus decreases. In addition, this PU/EP IPN matrix based MRE has a high-damping property, with high loss factor and can be controlled by applying magnetic field. It is expected that the high damping property and the ability of bi-directional magnetic-control modulus of this MRE offer promising advantages in seismologic application.

  18. Geoengineering and seismological aspects of the Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007

    Science.gov (United States)

    Kayen, R.; Brandenberg, S.J.; CoIlins, B.D.; Dickenson, S.; Ashford, S.; Kawamata, Y.; Tanaka, Y.; Koumoto, H.; Abrahamson, N.; Cluff, L.; Tokimatsu, K.

    2009-01-01

    The M6.6 Niigata-Ken Chuetsu-Oki earthquake of 16 July 2007 occurred off the west coast of Japan with a focal depth of 10 km, immediately west of Kashiwazaki City and Kariwa Village in southern Niigata Prefecture. Peak horizontal ground accelerations of 0.68 g were measured in Kashiwazaki City, as well as at the reactor floor level of the world's largest nuclear reactor, located on the coast at Kariwa Village. Liquefaction of historic and modern river deposits, aeolian dune sand, and manmade fill was widespread in the coastal region nearest the epicenter and caused ground deformations that damaged bridges, embankments, roadways, buildings, ports, railways and utilities. Landslides along the coast of southern Niigata Prefecture and in mountainous regions inland of Kashiwazaki were also widespread affecting transportation infrastructure. Liquefaction and a landslide also damaged the nuclear power plant sites. This paper, along with a companion digital map database available at http://walrus.wr.usgs.gOv/infobank/n/nii07jp/html/n-ii-07-jp.sites.kmz, describes the seismological and geo-engineering aspects of the event. ?? 2009, Earthquake Engineering Research Institute.

  19. Determination of the Alfvén Speed and Plasma-beta Using the Seismology of Sunspot Umbra

    Energy Technology Data Exchange (ETDEWEB)

    Cho, I.-H.; Moon, Y.-J.; Nakariakov, V. M.; Park, J.; Choi, S. [Department of Astronomy and Space Science, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Cho, K.-S.; Bong, S.-C.; Baek, J.-H.; Kim, Y.-H.; Lee, J., E-mail: ihjo@khu.ac.kr [Space Science Division, Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)

    2017-03-01

    For 478 centrally located sunspots observed in the optical continuum with Solar Dynamics Observatory /Helioseismic Magnetic Imager, we perform seismological diagnostics of the physical parameters of umbral photospheres. The new technique is based on the theory of slow magnetoacoustic waves in a non-isothermally stratified photosphere with a uniform vertical magnetic field. We construct a map of the weighted frequency of three-minute oscillations inside the umbra and use it for the estimation of the Alfvén speed, plasma-beta, and mass density within the umbra. We find the umbral mean Alfvén speed ranges between 10.5 and 7.5 km s{sup −1} and is negatively correlated with magnetic field strength. The umbral mean plasma-beta is found to range approximately between 0.65 and 1.15 and does not vary significantly from pores to mature sunspots. The mean density ranges between (1–6) × 10{sup −4} kg m{sup −3} and shows a strong positive correlation with magnetic field strength.

  20. Spatiotemporal Analysis of Coronal Loops Using Seismology of Damped Kink Oscillations and Forward Modeling of EUV Intensity Profiles

    Science.gov (United States)

    Pascoe, D. J.; Anfinogentov, S. A.; Goddard, C. R.; Nakariakov, V. M.

    2018-06-01

    The shape of the damping profile of kink oscillations in coronal loops has recently allowed the transverse density profile of the loop to be estimated. This requires accurate measurement of the damping profile that can distinguish the Gaussian and exponential damping regimes, otherwise there are more unknowns than observables. Forward modeling of the transverse intensity profile may also be used to estimate the width of the inhomogeneous layer of a loop, providing an independent estimate of one of these unknowns. We analyze an oscillating loop for which the seismological determination of the transverse structure is inconclusive except when supplemented by additional spatial information from the transverse intensity profile. Our temporal analysis describes the motion of a coronal loop as a kink oscillation damped by resonant absorption, and our spatial analysis is based on forward modeling the transverse EUV intensity profile of the loop under the isothermal and optically thin approximations. We use Bayesian analysis and Markov chain Monte Carlo sampling to apply our spatial and temporal models both individually and simultaneously to our data and compare the results with numerical simulations. Combining the two methods allows both the inhomogeneous layer width and density contrast to be calculated, which is not possible for the same data when each method is applied individually. We demonstrate that the assumption of an exponential damping profile leads to a significantly larger error in the inferred density contrast ratio compared with a Gaussian damping profile.

  1. Network of Research Infrastructures for European Seismology (NERIES)-Web Portal Developments for Interactive Access to Earthquake Data on a European Scale

    Science.gov (United States)

    Spinuso, A.; Trani, L.; Rives, S.; Thomy, P.; Euchner, F.; Schorlemmer, D.; Saul, J.; Heinloo, A.; Bossu, R.; van Eck, T.

    2009-04-01

    The Network of Research Infrastructures for European Seismology (NERIES) is European Commission (EC) project whose focus is networking together seismological observatories and research institutes into one integrated European infrastructure that provides access to data and data products for research. Seismological institutes and organizations in European and Mediterranean countries maintain large, geographically distributed data archives, therefore this scenario suggested a design approach based on the concept of an internet service oriented architecture (SOA) to establish a cyberinfrastructure for distributed and heterogeneous data streams and services. Moreover, one of the goals of NERIES is to design and develop a Web portal that acts as the uppermost layer of the infrastructure and provides rendering capabilities for the underlying sets of data The Web services that are currently being designed and implemented will deliver data that has been adopted to appropriate formats. The parametric information about a seismic event is delivered using a seismology-specific Extensible mark-up Language(XML) format called QuakeML (https://quake.ethz.ch/quakeml), which has been formalized and implemented in coordination with global earthquake-information agencies. Uniform Resource Identifiers (URIs) are used to assign identifiers to (1) seismic-event parameters described by QuakeML, and (2) generic resources, for example, authorities, locations providers, location methods, software adopted, and so on, described by use of a data model constructed with the resource description framework (RDF) and accessible as a service. The European-Mediterranean Seismological Center (EMSC) has implemented a unique event identifier (UNID) that will create the seismic event URI used by the QuakeML data model. Access to data such as broadband waveform, accelerometric data and stations inventories will be also provided through a set of Web services that will wrap the middleware used by the

  2. An infrastructure for data-intensive seismology using ADMIRE: laying the bricks for a new data highway

    Science.gov (United States)

    Trani, L.; Spinuso, A.; Galea, M.; Atkinson, M.; Van Eck, T.; Vilotte, J.

    2011-12-01

    primary goal was to evaluate its capabilities for large-scale integration and analysis of distributed data. A secondary goal was to gauge its potential and the added value that it might bring to the seismological community. Though still in its infant state, the architecture met the demands of our use case and promises to cater for our future requirements. We shall continue to develop its capabilities as part of an EU funded project VERCE - Virtual Earthquake and Seismology Research Community for Europe. VERCE aims to significantly advance our understanding of the Earth in order to aid society in its management of natural resources and hazards. Its strategy is to enable seismologists to fully exploit the under-utilized wealth of seismic data, and key to this is a data-intensive computation framework adapted to the scale and diversity of the community. This is a first step in building a data-intensive highway for geoscientists, smoothing their travel from the primary sources of data to new insights and rapid delivery of actionable information.

  3. Application of Adjoint Method and Spectral-Element Method to Tomographic Inversion of Regional Seismological Structure Beneath Japanese Islands

    Science.gov (United States)

    Tsuboi, S.; Miyoshi, T.; Obayashi, M.; Tono, Y.; Ando, K.

    2014-12-01

    Recent progress in large scale computing by using waveform modeling technique and high performance computing facility has demonstrated possibilities to perform full-waveform inversion of three dimensional (3D) seismological structure inside the Earth. We apply the adjoint method (Liu and Tromp, 2006) to obtain 3D structure beneath Japanese Islands. First we implemented Spectral-Element Method to K-computer in Kobe, Japan. We have optimized SPECFEM3D_GLOBE (Komatitsch and Tromp, 2002) by using OpenMP so that the code fits hybrid architecture of K-computer. Now we could use 82,134 nodes of K-computer (657,072 cores) to compute synthetic waveform with about 1 sec accuracy for realistic 3D Earth model and its performance was 1.2 PFLOPS. We use this optimized SPECFEM3D_GLOBE code and take one chunk around Japanese Islands from global mesh and compute synthetic seismograms with accuracy of about 10 second. We use GAP-P2 mantle tomography model (Obayashi et al., 2009) as an initial 3D model and use as many broadband seismic stations available in this region as possible to perform inversion. We then use the time windows for body waves and surface waves to compute adjoint sources and calculate adjoint kernels for seismic structure. We have performed several iteration and obtained improved 3D structure beneath Japanese Islands. The result demonstrates that waveform misfits between observed and theoretical seismograms improves as the iteration proceeds. We now prepare to use much shorter period in our synthetic waveform computation and try to obtain seismic structure for basin scale model, such as Kanto basin, where there are dense seismic network and high seismic activity. Acknowledgements: This research was partly supported by MEXT Strategic Program for Innovative Research. We used F-net seismograms of the National Research Institute for Earth Science and Disaster Prevention.

  4. EVIDENCE OF THERMAL CONDUCTION SUPPRESSION IN A SOLAR FLARING LOOP BY CORONAL SEISMOLOGY OF SLOW-MODE WAVES

    International Nuclear Information System (INIS)

    Wang, Tongjiang; Ofman, Leon; Provornikova, Elena; Sun, Xudong; Davila, Joseph M.

    2015-01-01

    Analysis of a longitudinal wave event observed by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory is presented. A time sequence of 131 Å images reveals that a C-class flare occurred at one footpoint of a large loop and triggered an intensity disturbance (enhancement) propagating along it. The spatial features and temporal evolution suggest that a fundamental standing slow-mode wave could be set up quickly after meeting of two initial disturbances from the opposite footpoints. The oscillations have a period of ∼12 minutes and a decay time of ∼9 minutes. The measured phase speed of 500 ± 50 km s −1 matches the sound speed in the heated loop of ∼10 MK, confirming that the observed waves are of slow mode. We derive the time-dependent temperature and electron density wave signals from six AIA extreme-ultraviolet channels, and find that they are nearly in phase. The measured polytropic index from the temperature and density perturbations is 1.64 ± 0.08 close to the adiabatic index of 5/3 for an ideal monatomic gas. The interpretation based on a 1D linear MHD model suggests that the thermal conductivity is suppressed by at least a factor of 3 in the hot flare loop at 9 MK and above. The viscosity coefficient is determined by coronal seismology from the observed wave when only considering the compressive viscosity dissipation. We find that to interpret the rapid wave damping, the classical compressive viscosity coefficient needs to be enhanced by a factor of 15 as the upper limit

  5. Direct seismic detection of gas hydrates using multi-component seismology : a case study from the mid-Norwegian margin

    Energy Technology Data Exchange (ETDEWEB)

    Bunz, S.; Mienert, J. [Tromso Univ., Tromso (Norway). Dept. of Geology; Chand, S. [Norwegian Geological Survey, Trondheim (Norway)

    2008-07-01

    Gas hydrates are important as a possible future energy resource, in submarine landsliding and in global climate change as they contain more carbon than any other global reservoir and are plentiful on continental margins worldwide. It is therefore necessary to identify and map the distribution of gas hydrates in a fast and basin-wide approach. Information about the distribution of gas hydrates can be obtained using multi-component seismology. In the marine environment shear waves (S-waves) can be generated by conversion from a downward-propagating compressional wave (P-wave) upon reflection at a sedimentary interface. The upward-propagating S-wave can be recorded at the ocean floor using vertical and horizontal geophones. On the mid-Norwegian margin, a combined analysis of the independently obtained parameters, P-wave velocity and Vp/Vs-ratio, of ocean-bottom cable data enables the direct detection of gas hydrates with higher certainty and assessment of their grain-scale distribution and its controlling parameters. In order to directly image gas hydrates and to directly assess their grain-scale distribution, a model was developed to evaluate the distribution of the ratio of P- and S-wave velocities, Vp/Vs, along the ocean-bottom cable line. The study also evaluated possible controlling mechanisms for the distribution of gas hydrates. The paper provided detailed information on the distribution of gas hydrates and gas within the sediments through analyses of seismic velocities, obtained from multi-channel or ocean-bottom seismic data. It was concluded that gas hydrates are distributed both with and without affecting the shear strength of the sediments. 13 refs., 6 figs.

  6. "Treatises on Earthquakes" in late Renaissance (16th-17th cent), at the roots of historical seismology

    Science.gov (United States)

    Albini, P.

    2009-04-01

    It was soon after the damaging November 1570 earthquake at Ferrara, Northern Italy, that the academic Stefano Breventano from Pavia, a small town in Northern Italy as well, started to compose his "Treatise on the earthquake". Completed by September 1576, this 250-page manuscript was to remain unpublished for centuries. The critical edition recently appeared (Albini, 2007) was a due tribute to the remarkable amount of information put together by Breventano, an otherwise "obscure" literate who, before getting involved with earthquakes, had published a history of the antiquities and remarkable events at his hometown Pavia (1570). Indeed, he was not the first Renaissance author to pursue the goal of checking into the historical sources of the previous centuries in search of earthquakes and other natural phenomena. What is outstanding in his "Treatise" is that he suceeded in retrieving information on more than two hundred earthquakes, along two thousand years, between 504 B.C. and 1575 A.D., covering the whole Euro-Mediterranean region, and the West Indies in early 16th century. Breventano's essay is here presented, together with a comparison between his style and amount of information with those included in the work by the contemporary British author Stephen Batman, "The Doome warning all men to the Judgement" (1581). A later treatise is presented also, the work by Marcello Bonito (1690) "Terra Tremante [Trembling Earth]", which could easily be defined as a worldwide list of earthquakes. In structure and content, Bonito's work goes along the same lines of Breventano, and could be considered a precursor of today descriptive catalogues, because of his outstandingly modern approach that paved the way to modern historical seismology.

  7. Characterization of Material Properties at Brady Hot Springs, Nevada by Inverse Modeling of Data from Seismology, Geodesy, and Hydrology

    Science.gov (United States)

    Wang, H. F.; Feigl, K. L.; Patterson, J.; Parker, L.; Reinisch, E. C.; Zeng, X.; Cardiff, M. A.; Fratta, D.; Lord, N. E.; Thurber, C. H.; Robertson, M.; Miller, D. E.; Akerley, J.; Kreemer, C.; Morency, C.; Davatzes, N. C.

    2017-12-01

    The PoroTomo project consists of poroelastic tomography by adjoint inverse modeling of data from seismology, geodesy, and hydrology. The goal of the PoroTomo project is to assess an integrated technology for characterizing and monitoring changes in the rock mechanical properties of an enhanced geothermal system in 3 dimensions with a spatial resolution better than 50 meters. In March 2016, we deployed the integrated technology in a 1500-by-500-by-400-meter volume at Brady. The 15-day deployment included 4 distinct time intervals with intentional manipulations of the pumping rates in injection and production wells. The data set includes: active seismic sources, fiber-optic cables for Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) arranged vertically in a borehole to 400 m depth and horizontally in a trench 8700 m in length and 0.5 m in depth; 244 seismometers on the surface, 3 pressure sensors in observation wells, continuous geodetic measurements at 3 GPS stations, and 7 InSAR acquisitions. To account for the mechanical behavior of both the rock and the fluids, we are developing numerical models for the 3-D distribution of the material properties. We present an overview of results, including:Tomographic images of P-wave velocity estimated from seismic body waves [Thurber et al., this meeting].Tomographic images of phase velocity estimated from ambient noise correlation functions [Zeng et al., this meeting].Models of volumetric contraction to account for subsidence observed by InSAR and GPS [Reinisch et al., this meeting].Interpretation of pressure and temperature data [Patterson et al., this meeting].Taken together, these results support a conceptual model of highly permeable conduits along faults channeling fluids from shallow aquifers to the deep geothermal reservoir tapped by the production wells. The PoroTomo project is funded by a grant from the U.S. Department of Energy.

  8. The Virtual Earthquake and Seismology Research Community e-science environment in Europe (VERCE) FP7-INFRA-2011-2 project

    Science.gov (United States)

    Vilotte, J.-P.; Atkinson, M.; Michelini, A.; Igel, H.; van Eck, T.

    2012-04-01

    Increasingly dense seismic and geodetic networks are continuously transmitting a growing wealth of data from around the world. The multi-use of these data leaded the seismological community to pioneer globally distributed open-access data infrastructures, standard services and formats, e.g., the Federation of Digital Seismic Networks (FDSN) and the European Integrated Data Archives (EIDA). Our ability to acquire observational data outpaces our ability to manage, analyze and model them. Research in seismology is today facing a fundamental paradigm shift. Enabling advanced data-intensive analysis and modeling applications challenges conventional storage, computation and communication models and requires a new holistic approach. It is instrumental to exploit the cornucopia of data, and to guarantee optimal operation and design of the high-cost monitoring facilities. The strategy of VERCE is driven by the needs of the seismological data-intensive applications in data analysis and modeling. It aims to provide a comprehensive architecture and framework adapted to the scale and the diversity of those applications, and integrating the data infrastructures with Grid, Cloud and HPC infrastructures. It will allow prototyping solutions for new use cases as they emerge within the European Plate Observatory Systems (EPOS), the ESFRI initiative of the solid Earth community. Computational seismology, and information management, is increasingly revolving around massive amounts of data that stem from: (1) the flood of data from the observational systems; (2) the flood of data from large-scale simulations and inversions; (3) the ability to economically store petabytes of data online; (4) the evolving Internet and Data-aware computing capabilities. As data-intensive applications are rapidly increasing in scale and complexity, they require additional services-oriented architectures offering a virtualization-based flexibility for complex and re-usable workflows. Scientific information

  9. Evolution of the Concordia seismological observatory station CCD (GEOSCOPE network): a new post-hole installation on Antarctica inlandsis

    Science.gov (United States)

    Zigone, D.; Danecek, P.; Bès de Berc, M.; Maggi, A.; Thore, J. Y.; Leveque, J. J.; Vallee, M.; Bernard, A.; Sayadi, J.; Morelli, A.; Delladio, A.; Chappellaz, J. A.; Alemany, O.; Possenti, P.; Stutzmann, E.; Bonaime, S.; Pesqueira, F.; Pardo, C.; Vincent, D.

    2017-12-01

    Concordia (75°S 123°E) is a scientific base operated by French polar institute IPEV (Institut Paul-Emile Victor) and Italian Antarctic Program PNRA (Programma Nazionale di Ricerche in Antartide), and is located at Dome C, on the ice sheet of the East Antarctica plateau. It hosts a seismological observatory (CCD), which is jointly operated by EOST (Strasbourg) and INGV (Roma). The highly strategic location and remoteness is the key strength of our program, which has provided observatory quality data since 2000. The station has been integrated into the GEOSCOPE network in 2008 and the data are now available in real time through GEOSCOPE and IRIS. The observatory is located at distance of 1km from the base. The current installation is placed at a depth of 12m in an artificial vault constructed from two shipping containers and buried in the snow. The vault is thermally very stable, but the relatively close proximity to the base causes increased diurnal noise ( 40 dB) at frequencies above 1Hz, especially during the summer season. The uppermost 100 m thick firn (snow) layer forms a waveguide, where anthropic noise from the base is trapped and easily picked up by the seismometers (T240 and STS2). Another limitation comes from the hydrostatic pressure of the snow which is continuously deforming the metallic structures: we record container cracking events on the seismograms, and we see visual evidence of structural deformations inside the tunnel and the vault. We propose an evolution of the CCD station towards a post-hole installation. Placing a sensor at a depth of approximately 130 meters, will reduce noise from thermal effects, from tilting and from anthropogenic activity, because it would be located below the firn layer waveguide and the ice pinch-out depth. In order to operate the borehole station for several years, we intend to keep the hole open and the sensor accessible, while ensuring good coupling between the sensor and the surrounding hard ice. To achieve these

  10. Research in Seismology

    Science.gov (United States)

    1975-01-01

    edge of the Persian Gulf, isolatina the Arabian continental shelf from the subduction process. Slippage along this fault is Pleistocene and probably...Fault-plane solutions for these events (Fitch, 1970; Nowroozi, 1972) confirm the mechanisms to be shallow underthrusting. The Bouguer gravity anomaly...at 40 km behind the subduction zone. A Bouguer gravity anomaly has also been calculated for this model by assuming that the structure is flat and

  11. Red giants seismology

    Science.gov (United States)

    Mosser, B.; Samadi, R.; Belkacem, K.

    2013-11-01

    The space-borne missions CoRoT and Kepler are indiscreet. With their asteroseismic programs, they tell us what is hidden deep inside the stars. Waves excited just below the stellar surface travel throughout the stellar interior and unveil many secrets: how old is the star, how big, how massive, how fast (or slow) its core is dancing. This paper intends to paparazze the red giants according to the seismic pictures we have from their interiors.

  12. Seismology for rockburst prediction.

    CSIR Research Space (South Africa)

    De Beer, W

    2000-02-01

    Full Text Available project GAP409 presents a method (SOOTHSAY) for predicting larger mining induced seismic events in gold mines, as well as a pattern recognition algorithm (INDICATOR) for characterising the seismic response of rock to mining and inferring future... State. Defining the time series of a specific function on a catalogue as a prediction strategy, the algorithm currently has a success rate of 53% and 65%, respectively, of large events claimed as being predicted in these two cases, with uncertainties...

  13. Yugoslav seismological research threatened

    Science.gov (United States)

    Allegretti, Ivo; Hamburger, Michael

    We in the Western scientific community have had the luxury, throughout most of our careers, of working in an environment insulated from the terrors of war and political violence. Well distanced from these horrors, we are often numbed by headlines reporting political turmoil elsewhere in the world—whether in Afghanistan, South Africa, or Yugoslavia. There are times, however, when personal contact with a colleague caught within one of these political wildfires reminds us of the very human tragedy that underlies these headlines.In studying a number of large earthquakes that took place in Central Asia in the 1930s and 1940s, we have been collecting seismograms from the well established European seismic observatories that recorded the events. Among them was the Zagreb Observatory, operated by the Mohorovicic Geophysical Institute of the University of Zagreb. The city of Zagreb—along with its scientific and cultural institutions—is now under siege, a result of the violent military conflict between the Yugoslav federal government and the Republic of Croatia. The following letter, which accompanied the Zagreb seismograms, provides a vivid picture of the daily hardships that our colleagues in Yugoslavia must be facing and a call to members of the international scientific community to help put an end to the rapidly escalating violence in Yugoslavia.

  14. Non-linear seismology

    CSIR Research Space (South Africa)

    Dzhafarov, AD

    1998-06-01

    Full Text Available . These methods make use of ray theory to model waveforms from finite sources, and allow the selective modelling of propagation effects for the different body wave types in arbitrarily complex three dimensional media....

  15. Research in Seismology

    Science.gov (United States)

    1977-12-31

    for several sandstones (Fatt and Davis, 1952), Westerly granite ( Frangos , 1967), and Ottawa sand (Zoback and Byerlee, 1976). In general, permeability...an order of magnitude ( Frangos , 1967). However, since the effect of fluid flow is negligible in all but the highly permeable rocks, we need only

  16. Seismology in Mexico

    Science.gov (United States)

    Lomnitz, C.

    1982-01-01

    Mexico is situated at the intersection of four major crustal Plates: the Americas Plate, the Pacific Plate, the Caribbean Plate, and the Cocos Plate. The interaction of these four plates is very complex. The pattern of earthquake risk is, therefore, among the most complicated in the world. The average release of seismic energy each is 55x1021 ergs-more than twice the figure for California. 

  17. A seismological study of shallow weak earthquakes in the urban area of Hamburg city, Germany, and its possible relation to salt dissolution

    Science.gov (United States)

    Dahm, Torsten; Heimann, Sebastian; Bialowons, Wilhelm

    2010-05-01

    In the night from 8/9 April 2009, shortly after midnight on Maundy Thursday before Easter, several people in Gross-Flottbek, Hamburg, felt unusual strong ground shocks so that some of them left their houses in fear of earthquake shaking. Police and Fire Brigade received phone calls of worried residents, and few days later Internet pages were published where people reported their observations. On 21 April 2009 at about 8 p.m. local time a second micro-earthquake was felt. Damage to buildings or infrastructure did not occur to our knowledge. The Institute of Geophysics, University of Hamburg, installed from 22 April to 17 May 2009 three temporal seismic stations in the epicentral area. Seismological data from two close-by stations at the Deutsches Elektron-Synchrotron (DESY) in about 1 km and the Geophysical Institute in about 7 km distance were collected and integrated to the temporal network. The events occurred above the roof of the shallow Othmarschen Langenfelde salt diapir (OLD), in an area known for active sinkhole formation and previous historic ground shaking events. The analysis of the seismological data recovers that three shallow micro-earthquakes occurred from 8 to 21 April at a depth of about 100m, the largest one with a moment magnitude of about MW 0.6. Depth location of such shallow events is difficult with standard methods, and is here constrained by waveform modeling of surface waves. Earthquakes occurring in soft sediments within the uppermost 100 m are a rare phenomena and cannot be explained by standard models. Rupture process in soft sediments differ from those on faults in more competent rock. We discuss the rupture and source mechanism of the earthquakes in the context of previous historic shocks and existing sinkhole and deformation data. Although the event was so weak, the rupture duration was unusual long and possibly 0.3 s. Three possible models for the generation of repeated micro-earthquakes in Gross Flottbek are developed and discussed

  18. 2D Modelling of the Gorkha earthquake through the joint exploitation of Sentinel 1-A DInSAR measurements and geological, structural and seismological information

    Science.gov (United States)

    De Novellis, Vincenzo; Castaldo, Raffaele; Solaro, Giuseppe; De Luca, Claudio; Pepe, Susi; Bonano, Manuela; Casu, Francesco; Zinno, Ivana; Manunta, Michele; Lanari, Riccardo; Tizzani, Pietro

    2016-04-01

    A Mw 7.8 earthquake struck Nepal on 25 April 2015 at 06:11:26 UTC, killing more than 9,000 people, injuring more than 23,000 and producing extensive damages. The main seismic event, known as the Gorkha earthquake, had its epicenter localized at ~82 km NW of the Kathmandu city and the hypocenter at a depth of approximately 15 km. After the main shock event, about 100 aftershocks occurred during the following months, propagating toward the south-east direction; in particular, the most energetic shocks were the Mw 6.7 and Mw 7.3 occurred on 26 April and 12 May, respectively. In this study, we model the causative fault of the earthquake by jointly exploiting surface deformation retrieved by the DInSAR measurements collected through the Sentinel 1-A (S1A) space-borne sensor and the available geological, structural and seismological information. We first exploit the analytical solution performing a back-analysis of the ground deformation detected by the first co-seismic S1A interferogram, computed by exploiting the 17/04/2015 and 29/04/2015 SAR acquisitions and encompassing the main earthquake and some aftershocks, to search for the location and geometry of the fault plane. Starting from these findings and by benefiting from the available geological, structural and seismological data, we carry out a Finite Element (FE)-based 2D modelling of the causative fault, in order to evaluate the impact of the geological structures activated during the seismic event on the distribution of the ground deformation field. The obtained results show that the causative fault has a rather complex compressive structure, dipping northward, formed by segments with different dip angles: 6° the deep segment and 60° the shallower one. Therefore, although the hypocenters of the main shock and most of the more energetic aftershocks are located along the deeper plane, corresponding to a segment of the Main Himalayan Thrust (MHT), the FE solution also indicates the contribution of the shallower

  19. Fault geometry of 2015, Mw7.2 Murghab, Tajikistan earthquake controls rupture propagation: Insights from InSAR and seismological data

    Science.gov (United States)

    Sangha, Simran; Peltzer, Gilles; Zhang, Ailin; Meng, Lingsen; Liang, Cunren; Lundgren, Paul; Fielding, Eric

    2017-03-01

    Combining space-based geodetic and array seismology observations can provide detailed information about earthquake ruptures in remote regions. Here we use Landsat-8 imagery and ALOS-2 and Sentinel-1 radar interferometry data combined with data from the European seismology network to describe the source of the December 7, 2015, Mw7.2 Murghab (Tajikistan) earthquake. The earthquake reactivated a ∼79 km-long section of the Sarez-Karakul Fault, a NE oriented sinistral, trans-tensional fault in northern Pamir. Pixel offset data delineate the geometry of the surface break and line of sight ground shifts from two descending and three ascending interferograms constrain the fault dip and slip solution. Two right-stepping, NE-striking segments connected by a more easterly oriented segment, sub-vertical or steeply dipping to the west were involved. The solution shows two main patches of slip with up to 3.5 m of left lateral slip on the southern and central fault segments. The northern segment has a left-lateral and normal oblique slip of up to a meter. Back-projection of high-frequency seismic waves recorded by the European network, processed using the Multitaper-MUSIC approach, focuses sharply along the surface break. The time progression of the high-frequency radiators shows that, after a 10 second initiation phase at slow speed, the rupture progresses in 2 phases at super-shear velocity (∼4.3-5 km/s) separated by a 3 second interval of slower propagation corresponding to the passage through the restraining bend. The intensity of the high-frequency radiation reaches maxima during the initial and middle phases of slow propagation and is reduced by ∼50% during the super-shear phases of the propagation. These findings are consistent with studies of other strike-slip earthquakes in continental domain, showing the importance of fault geometric complexities in controlling the speed of fault propagation and related spatiotemporal pattern of the high-frequency radiation.

  20. Seismological observations at the Northern Andean region of Colombia: Evidence for a shallowly subducting Caribbean Slab and an extensional regime in the upper plate

    Science.gov (United States)

    Monsalve, G.; Cardona, A.; Yarce, J.; Alvira, D.; Poveda, E.

    2013-05-01

    A number of seismological observations, among which we can mention teleseismic travel time residuals, P to S receiver functions and Pn velocity quantification, suggest a clear distinction between the seismic structure of the crust and uppermost mantle between the plains on the Caribbean coast of Colombia and the mountains at the Northern Andean region. Absolute and relative travel time residuals indicate the presence of a seismically fast material in the upper mantle beneath northern Colombia; preliminary results of Pn studies show a region of relatively slow Pn velocities (between 7.8 and 7.9 km/s) underneath the Caribbean coast, contrasting with values greater than 8 km/s beneath the Central and Western cordilleras of Colombia, and the Pacific coast; receiver functions suggest a significantly thinner crust beneath the Caribbean coast, with a crustal thickness between 25 and 30 km, than beneath the Northern Andean zone at the cordilleras of Colombia, where it exceeds 40 km and reaches about 57 km at the location of Bogota. Besides the obviuos discrepancies that appear in response to different topography, we think that the seismological observations are a consequence of the presence of two very distinct slab segments beneath Colombia and contrasting behaviors of the upper plate, which correspond to Caribbean and Nazca subductions. Our seismic observations can be explained by a shallowly subducting Caribbean Plate, in the absence of an asthenospheric wedge, that steepens at about the location of the Bucaramanga nest, and a thinned continental crust that reflects an extensional component linked to oblique convergence of the Caribbean, which contrasts with the crustal thickening in the Andean Cordillera linked to crustal shortening and Nazca plate subuction. These new data are consistent with the idea of of a relatively warm Nazca slab of Neogene age which seems to have a relatively frontal convergence, and a colder, more buoyant Caribbean slab which represents an

  1. NW transverse fault system in Southern Bogota, Colombia: New seismologic and structural evidences derived from focal mechanisms and stress field determination

    Science.gov (United States)

    Angel Amaya, J.; Fierro Morales, J.; Ordoñez Potes, M.; Blanco, M.

    2012-12-01

    We present new seismological, morphotectonic and structural data of the Southern Bogota area. The goals of the study were to characterize the NW transverse fault system and to evaluate its effect on seismic wave's generation and propagation. The data set included epicenters of the RSNC (Red Sismologica Nacional de Colombia) catalog over the period 1993-2012, historical description of seismic events (period 1644-1921), structural field data (scale 1:100000) and remote sensors interpretation. The methodology included the structural analysis of over 476 faults having a known sense of offset by using a least squares iterative inversion outlined by Angelier (1984) to determinate the mean deviatoric principal stress tensor. Preliminary conclusions showed that both propagation medium and direction are determined by the structural and mechanic conditions of the Southern Bogota Shear Zone (SBSZ) defined by Fierro & Angel, (2008) as a NW-SE oblique-slip fault zone within sinistral and normal regimes. Based on both data sources (focal mechanism and field structural data) we attempted to reconstruct the stress field starting with a strike slip faulting stress regime (S2 vertical), the solution yielded a ENE-WSW orientation for horizontal principal stress (S1). It is hypothesized that the NW oblique-slip fault zone may generate and/or propagate seismic waves, as a local source, implying local hazard to Bogota the capital city of Colombia with over 8 million habitants.

  2. Investigation of Non-Linear Dynamics of the Rock Massive,Using Seismological Catalogue data and Induction Electromagnetic Monitoring Data in a Rock Burst Mine.

    Science.gov (United States)

    Hachay, O. A.; Khachay, O. Y.; Klimko, V. K.; Shipeev, O. V.

    2012-04-01

    Geological medium is an open dynamical system, which is influenced on different scales by natural and man-made impacts, which change the medium state and lead as a result to a complicated many ranked hierarchic evolution. That is the subject of geo synergetics. Paradigm of physical mesomechanics, which was advanced by academician Panin V.E. and his scientific school, which includes the synergetic approach is a constructive method for research and changing the state of heterogenic materials [1]. That result had been obtained on specimens of different materials. In our results of research of no stationary geological medium in a frame of natural experiments in real rock massifs, which are under high man-made influence it was shown, that the state dynamics can be revealed with use synergetics in hierarchic medium. Active and passive geophysical monitoring plays a very important role for research of the state of dynamical geological systems. It can be achieved by use electromagnetic and seismic fields. Our experience of that research showed the changing of the system state reveals on the space scales and times in the parameters, which are linked with the peculiarities of the medium of the second or higher ranks [2-5]. Results of seismological and electromagnetic information showed the mutual additional information on different space-time levels of rock massive state, which are energetic influenced by explosions, used in mining technology. It is revealed a change of nonlinearity degree in time of the massive state by active influence on it. The description of massive movement in a frame of linear dynamical system does not satisfy the practical situation. The received results are of great significance because for the first time we could find the coincidences with the mathematical theory of open systems and experimental natural results with very complicated structure. On that base we developed a new processing method for the seismological information which can be used in

  3. Geophysical anomalies associated with Imjin River Belt (IRB) in the middle Korean Peninsula revealed by geomagnetic depth sounding and seismological data

    Science.gov (United States)

    Yang, J.; Choi, H.; Noh, M.; Im, C.

    2012-12-01

    Imjin River Belt (IRB), located in the middle of the Korean Peninsula, has been one of long-standing geological issues because it is a very important tectonic link to understand a tectonic evolution of north-eastern Asia including China, Korea and Japan. Although the IRB has been considered as an extension of collision belt between the North China Block (NCB) and South China Block (SCB), there is little geophysical observation or study on this issue. In recent, we compiled a new induction arrow map for the Korean Peninsula, on the basis of long-period magneto-telluric (MT) data and the geomagnetic depth sounding data performed since the late 1990's. This newly compiled map has finer spatial resolution expecially in the middle area of the peninsula, which helps us to present the geophysical evidence that the IRB is the continuation or extension of the collision belt to the peninsula. The overall pattern of induction arrows in the peninsula appears to indicate a northwest-southeast direction, which is well-known 'sea effect' by the surrounding seas. However, the results of observations in the middle of the peninsula distinctly show an anomalous pattern around the IRB, which can not be explained only by the surrounding seas. This anomalous pattern may be attributed to enhanced conductivity associated with tectonic events that Imjin River Belt has experienced. The 3-D electromagnetic modeling results, considering both surrounding seas and enhanced conductivity of the IRB, explain well the anomalous observations around the IRB. Furthermore, recent seismological study demonstrates that focal mechanism around the IRB is mainly normal faulting event, which may be interpreted as the reactivation of paleo structures that are related to the post collisional lithospheric delamination. All the geophysical evidences convince us that the IRB is an extension of the collision belt between the NCB and SCB to the peninsula.

  4. Magnitude And Distance Determination From The First Few Seconds Of One Three Components Seismological Station Signal Using Support Vector Machine Regression Methods

    Science.gov (United States)

    Ochoa Gutierrez, L. H.; Vargas Jimenez, C. A.; Niño Vasquez, L. F.

    2011-12-01

    The "Sabana de Bogota" (Bogota Savannah) is the most important social and economical center of Colombia. Almost the third of population is concentrated in this region and generates about the 40% of Colombia's Internal Brute Product (IBP). According to this, the zone presents an elevated vulnerability in case that a high destructive seismic event occurs. Historical evidences show that high magnitude events took place in the past with a huge damage caused to the city and indicate that is probable that such events can occur in the next years. This is the reason why we are working in an early warning generation system, using the first few seconds of a seismic signal registered by three components and wide band seismometers. Such system can be implemented using Computational Intelligence tools, designed and calibrated to the particular Geological, Structural and environmental conditions present in the region. The methods developed are expected to work on real time, thus suitable software and electronic tools need to be developed. We used Support Vector Machines Regression (SVMR) methods trained and tested with historic seismic events registered by "EL ROSAL" Station, located near Bogotá, calculating descriptors or attributes as the input of the model, from the first 6 seconds of signal. With this algorithm, we obtained less than 10% of mean absolute error and correlation coefficients greater than 85% in hypocentral distance and Magnitude estimation. With this results we consider that we can improve the method trying to have better accuracy with less signal time and that this can be a very useful model to be implemented directly in the seismological stations to generate a fast characterization of the event, broadcasting not only raw signal but pre-processed information that can be very useful for accurate Early Warning Generation.

  5. Ref Tek Ultra-low Power Seismic Recorder With Low-cost High Speed Internet Telemetry U An Advanced Real-time Seismological Data Acquisition System

    Science.gov (United States)

    Passmore, P.; Zimakov, L.; Rozhkov, M.

    The 3rd Generation Seismic Recorder, Model 130-01, has been designed to be easier to use - more compact, lighter in weight, lower power, and requires less maintenance than other recorders. Not only is the hardware optimized for field deployments, soft- ware tools as well have been specially developed to support both field and base station operation. The 130's case is a clamshell design, inherently waterproof, with easy access to all user features on the top of the unit. The 130 has 6 input/output connectors, an LCD display, and a removable lid on top of the case. There are two Channel input connectors on a 6-channel unit (only one on a 3-channel unit), a Terminal connector for setup and control, a Net connector combining Ethernet and Serial PPP for network access, a 12 VDC Power connector, and a GPS receiver connector. The LCD display allows the user to monitor the status of various sub systems within the 130 without having a terminal device attached. For storing large amounts of data the IBM MicrodriveTM is offered. User setup, control and status monitoring is done either with a Personal Digital Assistant (PDA) (Palm OS compatible) using our Palm Field Controller (PFC) software or from a PC/workstation using our REF TEK Network Controller (RNC) GUI interface. StarBand VSAT is the premier two-way, always-on, high-speed satellite Internet ser- vice. StarBand means high-speed Internet without the constraints and congestion of land-based cable or telephone networks. StarBand uses a single satellite dish antenna for receiving and for sending dataUno telephone connection is needed. The hardware ° cost is much less than standard VSAT equipment with double or single hop transmis- sion. REF TEK protocol (RTP) provides end-to-end error-correcting data transmission and command/control. StarBandSs low cost VSAT provides two-way, always-on, high speed satellite Internet data availability. REF TEK and StarBand create the most ad- vanced real-time seismological data acquisition

  6. Disseminated Museum Displays and Participation of Students from Underrepresented Populations in Polar Research: Education and Outreach for Joint Projects in GPS and Seismology Solid Earth Science Community

    Science.gov (United States)

    Eriksson, S. C.; Wilson, T. J.; Anandakrishnan, S.; Aster, R. C.; Johns, B.; Anderson, K.; Taber, J.

    2006-12-01

    Two Antarctic projects developed by solid earth scientists in the GPS and seismology communities have rich education and outreach activities focused on disseminating information gleaned from this research and on including students from underrepresented groups. Members of the UNAVCO and IRIS research consortia along with international partners from Australia, Canada, Chile, Germany, Italy, New Zealand and the U.K. aim to deploy an ambitious GPS/seismic network to observe the Antarctic glaciological and geologic system using a multidisciplinary and internationally coordinated approach. The second project supports this network. UNAVCO and IRIS are designing and building a reliable power and communication system for autonomous polar station operation which use the latest power and communication technologies for ease of deployment and reliable multi-year operation in severe polar environments. This project will disseminate research results through an IPY/POLENET web-based museum style display based on the next-generation "Museum Lite" capability primarily supported by IRIS. "Museum Lite" uses a standard PC, touch-screen monitor, and standard Internet browsers to exploit the scalability and access of the Internet and to provide customizable content in an interactive setting. The unit is suitable for research departments, public schools, and an assortment of public venues, and can provide wide access to real-time geophysical data, ongoing research, and general information. The POLENET group will work with members of the two consortia to provide content about the project and polar science in general. One unit is to be installed at Barrow's Ilisagvit College through the Barrow Arctic Science Consortium, one at McMurdo Station in Antarctica, and two at other sites to be determined (likely in New Zealand/Australia and in the U.S.). In January, 2006, Museum Lite exhibit was installed at the Amundsen-Scott South Pole Station. Evaluation of this prototype is underway. These

  7. Flare Seismology from SDO Observations

    Science.gov (United States)

    Lindsey, Charles; Martinez Oliveros, Juan Carlos; Hudson, Hugh

    2011-10-01

    Some flares release intense seismic transients into the solar interior. These transients are the sole instance we know of in which the Sun's corona exerts a conspicuous influence on the solar interior through flares. The desire to understand this phenomenon has led to ambitious efforts to model the mechanisms by which energy stored in coronal magnetic fields drives acoustic waves that penetrate deep into the Sun's interior. These mechanisms potentially involve the hydrodynamic response of the chromosphere to thick-target heating by high-energy particles, radiative exchange in the chromosphere and photosphere, and Lorentz-force transients to account for acoustic energies estimated up to at 5X10^27 erg and momenta of order 6X10^19 dyne sec. An understanding of these components of flare mechanics promises more than a powerful diagnostic for local helioseismology. It could give us fundamental new insight into flare mechanics themselves. The key is appropriate observations to match the models. Helioseismic observations have identified the compact sources of transient seismic emission at the foot points of flares. The Solar Dynamics Observatory is now giving us high quality continuum-brightness and Doppler observations of acoustically active flares from HMI concurrent with high-resolution EUV observations from AIA. Supported by HXR observations from RHESSI and a broad variety of other observational resources, the SDO promises a leading role in flare research in solar cycle 24.

  8. A discrimination problem from seismology

    International Nuclear Information System (INIS)

    Elvers, E.

    1975-12-01

    Seismic discrimination between earthquakes and underground nuclear explosions is studied, utilizing magnitudes of two kinds from several seismic stations. A model is given first, where the mean values of the magnitudes are linear fuctions of a parameter describing event size. It is shown how the model parameters can be estimated after a minor restriction on their space. When the discrimination rule is derived from the model, a few different approaches are considered, and they are shown to coincide. It is found reasonabel to use a discriminant, which is linear in the magnitudes, and explicit formulas are obtained. The power of the method is expressed by a measure of separation between the alternatives, which also shows the importance of the individual magnitudes. Missing data is a frequent problem in practice, and the case is treated where there is a detection threshold for one of the magnitudes. The classicfication probabilities are computed when applying the rule to the available magnitudes, and they depend on the event size. The method is not optimal, and it is shown that it can be improved by using the technique of identification by negative evidence, i.e. by utilizing the threshold as upper bound for a missing magnitude. The model is one of general use, and the results thus have a wider applicability. (author)

  9. Computational seismology a practical introduction

    CERN Document Server

    Igel, Heiner

    2016-01-01

    This volume is an introductory text to a range of numerical methods used today to simulate time-dependent processes in Earth science, physics, engineering, and many other fields. The physical problem of elastic wave propagation in 1D serves as a model system with which the various numerical methods are introduced and compared. The theoretical background is presented with substantial graphical material supporting the concepts. The results can be reproduced with the supplementary electronic material provided as Python codes embedded in Jupyter notebooks. The volume starts with a primer on the physics of elastic wave propagation, and a chapter on the fundamentals of parallel programming, computational grids, mesh generation, and hardware models. The core of the volume is the presentation of numerical solutions of the wave equation with six different methods: (1) the finite-difference method; (2) the pseudospectral method (Fourier and Chebyshev); (3) the linear finite-element method; (4) the spectral-element meth...

  10. Long Period Seismological Research Program

    Science.gov (United States)

    1974-10-31

    in central Asia as observed at the high-gain long- period sites. Preliminary results from observations at Chiang Mai (CHG) show that the complexity...Preliminary results from observations at Chiang Mai (CHG) show that the complexity of the surface wave signals from many events in the Tadzhik-Kirgiz...and receivers. A number of Interesting features can be illustrated by examining portions of three selsmograms recorded at Chiang Mai (CHO

  11. Borehole Seismology: Fundamentals and Applications

    International Nuclear Information System (INIS)

    Bohnhoff, Marco

    2014-01-01

    Because boring in itself is very expensive and instrumentation is required to endure high temperatures and pressures, deep borehole observation was accompanied by an economic risk. However, it has great advantages with respect to micro-earthquake observation, which is enriched with a short period vibration signal, because deep borehole observation greatly reduces short period noise. These kind advantages were explained by referring to the relationship between earthquake size and frequency range. Examples of seismic observation in a borehole in a geothermal field in El Salvador and a CO 2 confinement project in the western part of Canada were introduced. (authors)

  12. The reflection seismology measurement method

    International Nuclear Information System (INIS)

    Sprecher, C.

    1987-01-01

    Even though data acquisition and data processing procedures have become more and more complex in recent decades, the end products of a reflection seismic survey have remained simple and illustrative. A seismic section resembles a geological cross-section and can be interpreted without in-depth knowledge provided that the basic principles behind the method are understood. This article attempts to convey some insight into the methodology without claiming to be scientifically exact or complete. (author)

  13. Blind source deconvolution for deep Earth seismology

    Science.gov (United States)

    Stefan, W.; Renaut, R.; Garnero, E. J.; Lay, T.

    2007-12-01

    We present an approach to automatically estimate an empirical source characterization of deep earthquakes recorded teleseismically and subsequently remove the source from the recordings by applying regularized deconvolution. A principle goal in this work is to effectively deblur the seismograms, resulting in more impulsive and narrower pulses, permitting better constraints in high resolution waveform analyses. Our method consists of two stages: (1) we first estimate the empirical source by automatically registering traces to their 1st principal component with a weighting scheme based on their deviation from this shape, we then use this shape as an estimation of the earthquake source. (2) We compare different deconvolution techniques to remove the source characteristic from the trace. In particular Total Variation (TV) regularized deconvolution is used which utilizes the fact that most natural signals have an underlying spareness in an appropriate basis, in this case, impulsive onsets of seismic arrivals. We show several examples of deep focus Fiji-Tonga region earthquakes for the phases S and ScS, comparing source responses for the separate phases. TV deconvolution is compared to the water level deconvolution, Tikenov deconvolution, and L1 norm deconvolution, for both data and synthetics. This approach significantly improves our ability to study subtle waveform features that are commonly masked by either noise or the earthquake source. Eliminating source complexities improves our ability to resolve deep mantle triplications, waveform complexities associated with possible double crossings of the post-perovskite phase transition, as well as increasing stability in waveform analyses used for deep mantle anisotropy measurements.

  14. Seismology for rockbursts prevention, control and prediction.

    CSIR Research Space (South Africa)

    Mendecki, AJ

    1996-05-01

    Full Text Available This report discusses the routine seismic monitoring mechanism which was introduced in mines over 30 years ago with two major objectives in mind: to locate major seismic events and thus guide rescue operations and to detect potentials instabilities....

  15. Eastern and Southern Africa Seismological Working Group

    International Nuclear Information System (INIS)

    Ogubazghi, G.

    2002-01-01

    Member countries of the Eastern and Southern Africa Seismologica Working Group are listed. The presentation also gives the objectives, activities, date of birth and sponsors of the said ESARSWG. Areas of possible cooperation with CTBTO are indicated

  16. An event database for rotational seismology

    Science.gov (United States)

    Salvermoser, Johannes; Hadziioannou, Celine; Hable, Sarah; Chow, Bryant; Krischer, Lion; Wassermann, Joachim; Igel, Heiner

    2016-04-01

    The ring laser sensor (G-ring) located at Wettzell, Germany, routinely observes earthquake-induced rotational ground motions around a vertical axis since its installation in 2003. Here we present results from a recently installed event database which is the first that will provide ring laser event data in an open access format. Based on the GCMT event catalogue and some search criteria, seismograms from the ring laser and the collocated broadband seismometer are extracted and processed. The ObsPy-based processing scheme generates plots showing waveform fits between rotation rate and transverse acceleration and extracts characteristic wavefield parameters such as peak ground motions, noise levels, Love wave phase velocities and waveform coherence. For each event, these parameters are stored in a text file (json dictionary) which is easily readable and accessible on the website. The database contains >10000 events starting in 2007 (Mw>4.5). It is updated daily and therefore provides recent events at a time lag of max. 24 hours. The user interface allows to filter events for epoch, magnitude, and source area, whereupon the events are displayed on a zoomable world map. We investigate how well the rotational motions are compatible with the expectations from the surface wave magnitude scale. In addition, the website offers some python source code examples for downloading and processing the openly accessible waveforms.

  17. Seismology of the Oso-Steelhead landslide

    Science.gov (United States)

    Hibert, C.; Stark, C. P.; Ekström, G.

    2014-12-01

    We carry out a combined analysis of the short- and long-period seismic signals generated by the devastating Oso-Steelhead landslide that occurred on 22 March 2014. The seismic records show that the Oso-Steelhead landslide was not a single slope failure, but a succession of multiple failures distinguished by two major collapses that occurred approximately three minutes apart. The first generated long-period surface waves that were recorded at several proximal stations. We invert these long-period signals for the forces acting at the source, and obtain estimates of the first failure runout and kinematics, as well as its mass after calibration against the mass-center displacement estimated from remote-sensing imagery. Short-period analysis of both events suggests that the source dynamics of the second are more complex than the first. No distinct long-period surface waves were recorded for the second failure, which prevents inversion for its source parameters. However, by comparing the seismic energy of the short-period waves generated by both events we are able to estimate the volume of the second. Our analysis suggests that the volume of the second failure is about 15-30% of the total landslide volume, which is in agreement with ground observations.

  18. Seismological measurement of solar helium abundance

    International Nuclear Information System (INIS)

    Vorontsov, S.V.; Pamyatnykh, A.A.

    1991-01-01

    The internal structure and evolution of the Sun depends on its chemical composition, particularly the helium abundance. In addition, the helium abundance in the solar envelope is thought to represent the protosolar value, making it a datum of cosmological significance. Spectroscopic measurements of the helium abundance are uncertain, and the most reliable estimates until now have come from the calibration of solar evolutionary models. The frequencies of solar acoustic oscillations are sensitive, however, to the behaviour of the speed of sound in the Sun's helium ionization zone, which allows a helioseismological determination of the helium abundance. Sound-speed inversion of helioseismological data can be used for this purpose, but precise frequency measurements of high-degree oscillation modes are needed. Here we describe a new approach based on an analysis of the phase shift of acoustic waves of intermediate-degree modes. From the accurate intermediate-mode data now available, we obtain a helium mass fraction Y=0.25±0.01 in the solar convection zone, significantly smaller than the value Y=0.27-0.29 predicted by recent solar evolutionary models. The discrepancy indicates either that initial helium abundance was reduced in the envelope by downward diffusion or that the protosolar value was lower than currently accepted. (author)

  19. BAYESIAN MAGNETOHYDRODYNAMIC SEISMOLOGY OF CORONAL LOOPS

    International Nuclear Information System (INIS)

    Arregui, I.; Asensio Ramos, A.

    2011-01-01

    We perform a Bayesian parameter inference in the context of resonantly damped transverse coronal loop oscillations. The forward problem is solved in terms of parametric results for kink waves in one-dimensional flux tubes in the thin tube and thin boundary approximations. For the inverse problem, we adopt a Bayesian approach to infer the most probable values of the relevant parameters, for given observed periods and damping times, and to extract their confidence levels. The posterior probability distribution functions are obtained by means of Markov Chain Monte Carlo simulations, incorporating observed uncertainties in a consistent manner. We find well-localized solutions in the posterior probability distribution functions for two of the three parameters of interest, namely the Alfven travel time and the transverse inhomogeneity length scale. The obtained estimates for the Alfven travel time are consistent with previous inversion results, but the method enables us to additionally constrain the transverse inhomogeneity length scale and to estimate real error bars for each parameter. When observational estimates for the density contrast are used, the method enables us to fully constrain the three parameters of interest. These results can serve to improve our current estimates of unknown physical parameters in coronal loops and to test the assumed theoretical model.

  20. GEOS seismograms for aftershocks of the earthquakes of December 7, 1988, near Spitak, Armenia SSR, during the time period 30 December 1988 14:00 through 2 January 1989 (UTC): Chapter D in Results and data from seismologic and geologic studies following earthquakes of December 7, 1988, near Spitak, Armenia SSR (Open-File Report 89-163)

    Science.gov (United States)

    Borcherdt, R.D.; Glassmoyer, Gary; Cranswick, Edward

    1989-01-01

    The earthquakes of December 7, 1988, near Spitak, Armenia SSR, serve as another grim reminder of the serious hazard that earthquakes pose throughout the world. We extend our heartfelt sympathies to the families of the earthquake victims and intend that our cooperative scientific endeavours will help reduce losses in future earthquakes. Only through a better understanding of earthquake hazards can earthquake losses be reduced for all peoples in seismically active regions of the world.The tragic consequences of these earthquakes remind scientists and public officials alike of their urgent responsibilities to understand and mitigate the effects of earthquakes. On behalf of the U.S. Geological Survey, I would like to express appreciation to our Soviet colleagues for their kind invitation to participate in joint scientific and engineering studies. Without their cooperation and generous assistance, the conduct of these studies would not have been possible.This report provides seismologic and geologic data collected during the time period December 21, 1988, through February 2, 1989. These data are presented in their entirety to expedite analysis of the data set for inferences regarding hazard mitigation actions, applicable not only in Armenia but other regions of the world exposed to high seismic risk

  1. In Jules Verne's Footsteps: Seismology in the source

    Science.gov (United States)

    Ellsworth, Bill; Ito, Hisao; Malin, Peter; Abercrombie, Rachel

    When Professor Otto Lidenbrock led his little band to the center of the Earth in Jules Verne's 1864 classic novel, the intrepid adventurers needed little more than practical 19th century clothes to provide them with comfort and protection. How different the science of earthquakes would be if conditions in the Earth were really so friendly to the would-be observer. Even the operation of seismic sensors at the relatively modest depth of 2-3 km, roughly the depth of the shallowest crustal earthquakes, requires careful precautions against the effects of unstable materials, temperature, pressure, and water for successful long-term observations to be made. Indeed, the handful of successful deep borehole experiments that have been conducted to date have depended on simple sensors with limited bandwidth and dynamic range, and have yielded data that were not ideally suited to investigating the details of the earthquake source.

  2. Seismology with Mermaids: Statistics from the Galapagos Experiment

    Science.gov (United States)

    Hello, Y.; Nolet, G.; Bonnieux, S.; Pazmino, A.; van der Lee, S.; Simons, F.; Chen, J.

    2017-12-01

    The operation of a small network of Mermaids for more than two years near the Galapagos Islands has provided with us the first experience of launching and following a mobile network of floating seismographs that transmit triggered signals by satellite (Rudics-Iridium).In mid 2014 we launched ten Mermaids of the first generation. The float that hosts the seismic instrumentation is an APEX float, the same as used by oceanographers in the Argo project.We lost contact with one of the floats after only one surfacing, in which it transmitted a time-depth history indicating a change of weight (leakage or fouling is suspected). The other nine surfaced on average 126 times before running out of power. They had an average lifespan of 616 days, with the longest lifespan 901 days. Earlier tests showed that power consumption is roughly divided equally between pump, CPU and transmission, and the large variety of lifespans indicate that unknown causes other than depletion of the battery may be at work, certainly in case of the one Mermaid that surfaced only 40 times.In total the nine Mermaids transmitted 1329 signals, of which 719 were associated with the arrival of an earthquake signal using our automatized data management software. Inspection by eye identified additional signals in the remaining records that are likely local earthquakes of small magnitude for which information in the catalogues is lacking, but most of them constitute false triggers.The success of a trigger depends very much on noise conditions that may be very local. The high frequency content of deep quakes makes them somewhat easier to identify than shallow ones. Teleseismic events with magnitudes higher than 5.5 can trigger successfully under quiet conditions, but even strong earthquakes can be missed during a storm. The experience with this first generation Mermaid has led us to develop the current version which has a larger battery capacity (expected lifespan 5 years) and the ability to recover missed triggers by commands via the satellite.

  3. Basic earthquake engineering from seismology to analysis and design

    CERN Document Server

    Sucuoğlu, Halûk

    2014-01-01

    This book provides senior undergraduate students, master students and structural engineers who do not have a background in the field with core knowledge of structural earthquake engineering that will be invaluable in their professional lives. The basics of seismotectonics, including the causes, magnitude, and intensity of earthquakes, are first explained. Then the book introduces basic elements of seismic hazard analysis and presents the concept of a seismic hazard map for use in seismic design. Subsequent chapters cover key aspects of the response analysis of simple systems and building struc­tures to earthquake ground motions, design spectrum, the adoption of seismic analysis procedures in seismic design codes, seismic design principles and seismic design of reinforced concrete structures. Helpful worked examples on seismic analysis of linear, nonlinear and base isolated buildings, earthquake-resistant design of frame and frame-shear wall systems are included, most of which can be solved using a hand calcu...

  4. Beyond space and time: advanced selection for seismological data

    Science.gov (United States)

    Trabant, C. M.; Van Fossen, M.; Ahern, T. K.; Casey, R. E.; Weertman, B.; Sharer, G.; Benson, R. B.

    2017-12-01

    Separating the available raw data from that useful for any given study is often a tedious step in a research project, particularly for first-order data quality problems such as broken sensors, incorrect response information, and non-continuous time series. With the ever increasing amounts of data available to researchers, this chore becomes more and more time consuming. To assist users in this pre-processing of data, the IRIS Data Management Center (DMC) has created a system called Research Ready Data Sets (RRDS). The RRDS system allows researchers to apply filters that constrain their data request using criteria related to signal quality, response correctness, and high resolution data availability. In addition to the traditional selection methods of stations at a geographic location for given time spans, RRDS will provide enhanced criteria for data selection based on many of the measurements available in the DMC's MUSTANG quality control system. This means that data may be selected based on background noise (tolerance relative to high and low noise Earth models), signal-to-noise ratio for earthquake arrivals, signal RMS, instrument response corrected signal correlation with Earth tides, time tear (gaps/overlaps) counts, timing quality (when reported in the raw data by the datalogger) and more. The new RRDS system is available as a web service designed to operate as a request filter. A request is submitted containing the traditional station and time constraints as well as data quality constraints. The request is then filtered and a report is returned that indicates 1) the request that would subsequently be submitted to a data access service, 2) a record of the quality criteria specified and 3) a record of the data rejected based on those criteria, including the relevant values. This service can be used to either filter a request prior to requesting the actual data or to explore which data match a set of enhanced criteria without downloading the data. We are optimistic this capability will reduce the initial data culling steps most researchers go through. Additionally, use of this service should reduce the amount of data transmitted from the DMC, easing the workload for our finite shared resources.

  5. Infrasound research at Kola Regional Seismological Centre, Russia

    Science.gov (United States)

    Asming, Vladimir; Kremenetskaya, Elena

    2013-04-01

    A small-aperture infrasound array has been installed in Kola Peninsula, Russia 17 km far from the town of Apatity in the year 2000. It comprises 3 Chaparral V microbarographs placed closely to the APA seismic array sensors and equipped with pipe wind reducing filters. The data are digitized at the array site and transmitted in real time to a processing center in Apatity. To search for infrasound events (arrivals of coherent signals) a beamforming-style detector has been developed. Now it works in near real time. We analyzed the detecting statistics for different frequency bands. Most man-made events are detected in 1-5 Hz band, microbaromes are typically detected in 0.2-1 Hz band. In lower frequencies we record mostly a wind noise. A data base of samples of infrasound signals of different natures has been collected. It contains recordings of microbaromes, industrial and military explosions, airplane shock waves, infrasound of airplanes, thunders, rocket launches and reentries, bolides etc. The most distant signals we have detected are associated with Kursk Magnetic Anomaly explosions (1700 km far from Apatity). We implemented an algorithm for association of infrasound signals and preliminary location of infrasound events by several arrays. It was tested with Apatity data together with data of Sweden - Finnish infrasound network operated by the Institute of Space Physics in Umea (Sweden). By agreement with NORSAR we have a real-time access to the data of Norwegian experimental infrasound installation situated in Karasjok (North Norway). Currently our detection and location programs work both with Apatity and Norwegian data. The results are available in Internet. Finnish militaries routinely destroy out-of-date weapon in autumns at the same compact site in North Finland. This is a great source of repeating infrasound signals of the same magnitude and origin. We recorded several hundreds of such explosions. The signals have been used for testing our location routines. Some factors were observed enabling or disabling first (tropospheric) arrivals of such signals depending on weather conditions. Systematic backazimuth deviations for stratospheric arrivals have been observed caused by strong stratospheric winds. In 2009 mobile infrasound arrays were developed in KRSC. Each array comprises 3 low-frequency microphones, GPS, digitizer and PC with data acquisition system. Aperture of such arrays is about 250 m, deployment time is less than 1 hour. These arrays are used in experimental work with Roskosmos space agency to search space debris reentering places. In 2012 a wireless version of such mobile array was created. Each acquisition point comprises a microphone, GPS and ADC chips, microcontroller and radio modem to send data to a central unit. This enabled us to increase aperture (up to 500 m) and decrease deployment time.

  6. Seismology and geodesy of the sun: Low-frequency oscillations.

    Science.gov (United States)

    Dicke, R H

    1981-04-01

    The hourly averages of the solar ellipticity measured from June 13 to Sept. 17, 1966, are analyzed for indications of solar oscillations with periods in excess of 2 hr nu 0.1 hr(-1) but for lower frequencies the power spectrum shows a very complex structure containing about 20 strong narrow peaks. The complexity is illusionary. The signal apparently consists of only two frequencies. The complexity is due to aliasing by the window function with its basic 24-hr period, with many observational days missing, and with different numbers of hourly averages for the various observational days. Both signal frequencies are apparently due to odd-degree spherical harmonic oscillations of the sun.

  7. Seismology and geodesy of the sun: Solar geodesy.

    Science.gov (United States)

    Dicke, R H

    1981-03-01

    Measurements of the elliptical figure of the sun made in 1966 are analyzed on an hourly basis. This analysis yields an improved measure of the previously found solar distortion, rotating rigidly with a sidereal period of 12.38+/-0.10 days. It also yields a set of residùals used to search for signals due to low-frequency solar oscillations.

  8. Seismology and geodesy of the sun: low-frequency oscillations

    International Nuclear Information System (INIS)

    Dicke, R.H.

    1981-01-01

    The hourly averages of the solar ellipticity measured from June 13 to September 17, 1966, are analyzed for indications of solar oscillations with periods in excess of 2 h ν -1 . Nothing significant is found for frequencies ν > 0.1 hr -1 but for lower frequencies the power spectrum shows a very complex structure containing about 20 strong narrow peaks. The complexity is illusionary. The signal apparently consists of only two frequencies. The complexity is due to aliasing by the window function with its basic 24-h period, with many observational days missing, and with different numbers of hourly averages for the various observational days. Both signal frequencies are apparently due to odd-degree spherical harmonic oscillations of the sun

  9. Seismology of rapidly rotating and solar-like stars

    Science.gov (United States)

    Reese, Daniel Roy

    2018-05-01

    A great deal of progress has been made in stellar physics thanks to asteroseismology, the study of pulsating stars. Indeed, asteroseismology is currently the only way to probe the internal structure of stars. The work presented here focuses on some of the theoretical aspects of this domain and addresses two broad categories of stars, namely solar-like pulsators (including red giants), and rapidly rotating pulsating stars. The work on solar-like pulsators focuses on setting up methods for efficiently characterising a large number of stars, in preparation for space missions like TESS and PLATO 2.0. In particular, the AIMS code applies an MCMC algorithm to find stellar properties and a sample of stellar models which fit a set of seismic and classic observational constraints. In order to reduce computation time, this code interpolates within a precalculated grid of models, using a Delaunay tessellation which allows a greater flexibility on the construction of the grid. Using interpolated models based on the outputs from this code or models from other forward modelling codes, it is possible to obtain refined estimates of various stellar properties such as the mean density thanks to inversion methods put together by me and G. Buldgen, my former PhD student. Finally, I show how inversion-type methods can also be used to test more qualitative information such as whether a decreasing rotation profile is compatible with a set of observed rotational splittings and a given reference model. In contrast to solar-like pulsators, the pulsation modes of rapidly rotating stars remain much more difficult to interpret due to the complexity of the numerical calculations needed to calculate such modes, the lack of simple frequency patterns, and the fact that it is difficult to predict mode amplitudes. The work described here therefore focuses on addressing the above difficulties one at a time in the hopes that it will one day be possible to carry out detailed asteroseismology in these stars. First of all, the non-adiabatic pulsation equations and their numerical implementation are described. The variational principle and work integrals are addressed. This is followed by a brief classification of the pulsation modes one can expect in rapidly rotating stars. I then address the frequencies patterns resulting from acoustic island modes and the interpretations of observed pulsation spectra based on these. This is then followed by a description of mode identification techniques and the ongoing efforts to adapt them to rapid rotation. Finally, the last part briefly deals with mode excitation.

  10. Changes in Greenland ice bed conditions inferred from seismology

    Science.gov (United States)

    Toyokuni, Genti; Takenaka, Hiroshi; Takagi, Ryota; Kanao, Masaki; Tsuboi, Seiji; Tono, Yoko; Childs, Dean; Zhao, Dapeng

    2018-04-01

    Basal conditions of the Greenland Ice Sheet (GrIS) are a key research topic in climate change studies. The recent construction of a seismic network has provided a new opportunity for direct, real-time, and continuous monitoring of the GrIS. Here we use ambient noise surface wave data from seismic stations all over Greenland for a 4.5-year period to detect changes in Rayleigh-wave phase velocity between seismic station pairs. We observe clear seasonal and long-term velocity changes for many pairs, and propose a plausible mechanism for these changes. Dominant factors driving the velocity changes might be seasonal and long-term pressurization/depressurization of the GrIS and shallow bedrock by air and ice mass loading/unloading. However, heterogeneity of the GrIS basal conditions might impose strong regionalities on the results. An interesting feature is that, even at adjacent two station pairs in the inland GrIS, one pair shows velocity decrease while another shows velocity increase as a response to the high air and snow pressure. The former pair might be located on a thawed bed that decreases velocity by increased meltwater due to pressure melting, whereas the latter pair might be located on a frozen bed that increases velocity by compaction of ice and shallow bedrock. The results suggest that surface waves are very sensitive to the GrIS basal conditions, and further observations will contribute to a more direct and quantitative estimation of water balance in the Arctic region.

  11. Seismological evidence of the Hales discontinuity in northeast India

    Science.gov (United States)

    Anand, Aakash; Bora, Dipok K.; Borah, Kajaljyoti; Madhab Borgohain, Jayanta

    2018-04-01

    The crust and upper mantle shear wave velocity structure beneath the northeast India is estimated by joint inversion of Rayleigh wave group velocity and receiver function, calculated from teleseismic earthquakes data recorded at nine broadband seismic stations. The Assam valley and the Shillong-Mikir plateau are the two important tectonic blocks in the northeast India, which are surrounded by the Himalayan collision zone in the north, Indo-Burma subduction zone in the east and by the Bengal basin in the south. The joint inversion followed by forward modeling reveal crustal thicknesses of 30-34 km beneath the Shillong plateau, 36 km beneath the Mikir hills and 38-40 km beneath the Assam valley with an average shear wave velocity (Vs) of 3.4-3.5 km/s. The estimated low upper mantle shear wave velocity (Vsn) 4.2-4.3 km/s may be due to the rock composition or grain size or increased temperature and partial melt (<1%) in the upper mantle, or an effect of all. Also, we report for the first time, the existence of the Hales discontinuity at depths 56-74 km with Vs ∼4.4-4.6 km/s. Variable depth of the Hales discontinuity may be explained by the geotherm and/or addition of Cr3+ and Fe2+ in the spinel-garnet system.

  12. Planetary Seismology : Lander- and Wind-Induced Seismic Signals

    Science.gov (United States)

    Lorenz, Ralph

    2016-10-01

    Seismic measurements are of interest for future geophysical exploration of ocean worlds such as Europa or Titan, as well as Venus, Mars and the Moon. Even when a seismometer is deployed away from a lander (as in the case of Apollo) lander-generated disturbances are apparent. Such signatures may be usefully diagnostic of lander operations (at least for outreach), and may serve as seismic excitation for near-field propagation studies. The introduction of these 'spurious' events may also influence the performance of event detection and data compression algorithms.Examples of signatures in the Viking 2 seismometer record of lander mechanism operations are presented. The coherence of Viking seismometer noise levels and wind forcing is well-established : some detailed examples are examined. Wind noise is likely to be significant on future Mars missions such as InSight, as well as on Titan and Venus.

  13. Seismological observations of glaciers dynamic on the Spitsbergen archipelago

    Directory of Open Access Journals (Sweden)

    Fedorov A. V.

    2016-03-01

    Full Text Available The paper provides a brief description of results of Spitsbergen glacier observations by the seismic method. The study has been carried out both by permanent and temporary stations data. Characteristic features of glacier-related seismic events have been shown. Main areas of glacier seismic activity on the Archipelago have been revealed. A detailed study of Horsund-fjord glacier activity has been carried out using local seismic station HSPB data. Temporal and spatial distributions of glacier-related events have been obtained for the area. Season variations in temporal distribution of the events have been found

  14. On the Use of Quality Factor in Seismology (Invited)

    Science.gov (United States)

    Morozov, I. B.

    2009-12-01

    Despite its canonical character and widespread use in attenuation studies, suitability of the quality factor Q for describing the Earth still needs to be reviewed. Specifically, we need to consider the following fundamental questions: 1) How close is Q-1 to representing a true medium property? 2) Theoretically, can or should Q-1 be related to complex arguments of the elastic moduli of the medium? and 3) What attenuation property is typically measured and transformed into Q? An attempt for answering these questions shows that not Q but the spatial attenuation coefficient, α, represents a consistent property of energy dissipation by the medium which is also actually measured in most cases. Transformation of α into the apparent Q = πf/αV (V is the wave velocity and f - frequency) makes this Q a phenomenological attribute of the wave and also leads to its built-in positive frequency dependence. Such strong positive Q(f) is often reported, particularly for the “scattering Q,” but it may be entirely due to near-constant values of α. The above transformation is also prone of the well-known uncertainties related to the compensation of geometrical spreading (GS). Q can be adequately used to model wave amplitudes but it includes the effects of the structure (e.g., diving or reflected-wave GS) but becomes ambiguous when applied to describing the in-situ attenuation. By using α(f) in interpretation, such effects are explicitly measured, and several general observations can be made, such as: 1) α(f) often shows linear dependencies on f in both real data and modeling, whereas the corresponding Q(f) may be complex; 2) the zero-frequency limit of α(f)=γ can be interpreted as a generalized measure of geometrical spreading, and 3) frequency-dependent in-situ Q is not as widespread as it is commonly thought. Quantity γ is variable and correlates with tectonic age of the lithosphere, whereas the effective frequency-independent Qe is typically significantly higher than the 1-Hz Q0 often found in the Q(f)=Q0fη law with η>0. Notably, γ appears to be consistently positive for body and surface waves, and negative for normal modes, leading to the apparent absorption band. Turning to the theoretical aspects of Q, energy dissipation is related to multiple external factors such as fracturing, fluid content and saturation, viscosity, porosity, permeability, properties of “dry” friction, and distributions of scatterers. Generally, all of these factors cannot be lumped in an unambiguous Q-1 or relaxation mechanisms included in the in-situ elastic moduli, as it is often assumed in visco-elastic models. Such assumptions may lead to observable discrepancies, such as opposite phases of reflections from attenuation contrasts, compared to the results of direct derivations from wave equations. Thus, the elastic moduli should better be treated as real and "instantaneous," and Lagrangian dissipation functions used to describe the attenuation. Further, and again contrary to what is often assumed, attenuation sensitivity kernels are different from velocity kernels. As illustrated on a 1D Love-wave example, usual assumptions of their equivalence lead to ~20% over-estimated predictions of the observed Love-wave QL-1. Once again, the use of α(f)) instead of Q rectifies this problem. The above conclusions may have major implications for measuring, modeling, inverting, and interpreting the Earth's attenuation.

  15. Probing the Cypriot Lithosphere: Insights from Broadband Seismology

    Science.gov (United States)

    Ogden, C. S.; Bastow, I. D.; Pilidou, S.; Dimitriadis, I.; Iosif, P.; Constantinou, C.; Kounoudis, R.

    2017-12-01

    Cyprus, an island in the eastern Mediterranean Sea, is an ideal study locale for understanding both the final stages of subduction, and the internal structure of so-called `ophiolites' - rare, on-land exposures of oceanic crust. The Troodos ophiolite offers an excellent opportunity to interrogate a complete ophiolite sequence from mantle rocks to pillow lavas. However, determining its internal architecture, and that of the subducting African plate deep below it, cannot be easily achieved using traditional field geology. To address this issue, we have built a new network of five broadband seismograph stations across the island. These, along with existing permanent stations, record both local and teleseismic earthquakes that we are now using to image Cyprus' crust and mantle seismic structure. Receiver functions are time series, computed from three-component seismograms, which contain information about lithospheric seismic discontinuities. When a P-wave strikes a velocity discontinuity such as the Moho, energy is converted to S-waves (direct Ps phase). The widely-used H-K Stacking technique utilises this arrival, and subsequent crustal reverberations (PpPs and PsPs+PpSs), to calculate crustal thickness (H) and bulk-crustal Vp/Vs ratio (K). Central to the method is the assumption that the Moho produces the largest amplitude conversions, after the direct P-arrival, which is valid where the Moho is sharp. Where the Moho is gradational or upper crustal discontinuities are present, the Moho signals are weakened and masked by shallow crustal conversions, potentially rendering the H-K stacking method unreliable. Using a combination of synthetic and observed seismograms, we explore Cyprus' crustal structure and, specifically, the reliability of the H-K method in constraining it. Data quality is excellent across the island, but the receiver function Ps phase amplitude is low, and crustal reverberations are almost non-existent. Therefore, a simple, abrupt wavespeed jump at the Moho is lacking (perhaps due to the subducting African plate), and/or evidence for it is obscured by complex structure associated with the Troodos ophiolite. On-going analyses also include joint inversion of receiver functions and surface wave data, which together, are capable of resolving complex lithospheric seismic structure.

  16. Geodetic and seismological investigation in the Ionian area

    Directory of Open Access Journals (Sweden)

    F. Riguzzi

    1997-06-01

    Full Text Available Geodetic and seismic evidence of crustal deformations in the Ionian area are shown in this paper. The Ionian GPS network, composed of nine sites crossing the Ionian Sea from Calabria, Southern Italy, to Northwestern Greece, was established and surveyed in 1991, 1994, 1995 within the framework of the TYRGEONET project (Anzidei et al., 1996. In 1996 a return campaign was carried out after the occurrence of seismic activity in 1995. The displacement pattern obtained for the Greek side of the network agrees well with those previously displayed, both in magnitude and direction, confirming a mean displacement rate of about 1-2 cm1/yr. The same agreement is not found for the Italian side of the network, where no significant deformations were detected between 1994 and 1996. Seismic deformation was also studied for the same area, starting from the moment tensors of events which occurred in the last 20 years with magnitude greater than 5.0; evident similarity with the displacement field exhibited by the Greek side of the Ionian Sea by geodetic surveys was inferred. On the contrary, the motion detected for the Italian area cannot be simply related to seismic activity.

  17. Towards age/rotation/magnetic activity relation with seismology

    Directory of Open Access Journals (Sweden)

    Mathur Savita

    2015-01-01

    Full Text Available The knowledge of stellar ages directly impacts the characterization of a planetary system as it puts strong constraints on the moment when the system was born. Unfortunately, the determination of precise stellar ages is a very difficult task. Different methods can be used to do so (based on isochrones or chemical element abundances but they usually provide large uncertainties. During its evolution a star goes through processes leading to loss of angular momentum but also changes in its magnetic activity. Building rotation, magnetic, age relations would be an asset to infer stellar ages model independently. Several attempts to build empirical relations between rotation and age (namely gyrochronology were made with a focus on cluster stars where the age determination is easier and for young stars on the main sequence. For field stars, we can now take advantage of high-precision photometric observations where we can perform asteroseismic analyses to improve the accuracy of stellar ages. Furthermore, the variability in the light curves allow us to put strong constraints on the stellar rotation and magnetic activity. By combining these precise measurements, we are on the way of understanding and improving relations between magnetic activity, rotation, and age, in particular at different stages of stellar evolution. I will review the status on gyrochronology relationships based on observations of young cluster stars. Then I will focus on solar-like stars and describe the inferences on stellar ages, rotation, and magnetism that can be provided by high-quality photometric observations such as the ones of the Kepler mission, in particular through asteroseismic analyses.

  18. Coronal Seismology: The Search for Propagating Waves in Coronal Loops

    Science.gov (United States)

    Schad, Thomas A.; Seeley, D.; Keil, S. L.; Tomczyk, S.

    2007-05-01

    We report on Doppler observations of the solar corona obtained in the Fe XeXIII 1074.7nm coronal emission line with the HAO Coronal Multi-Channel Polarimeter (CoMP) mounted on the NSO Coronal One Shot coronagraph located in the Hilltop Facility of NSO/Sacramento Peak. The COMP is a tunable filtergraph instrument that records the entire corona from the edge of the occulting disk at approximately 1.03 Rsun out to 1.4 Rsun with a spatial resolution of about 4” x 4”. COMP can be rapidly scanned through the spectral line while recording orthogonal states of linear and circular polarization. The two dimensional spatial resolution allows us to correlate temporal fluctuations observed in one part of the corona with those seen at other locations, in particular along coronal loops. Using cross spectral analysis we find that the observations reveal upward propagating waves that are characterized by Doppler shifts with rms velocities of 0.3 km/s, peak wave power in the 3-5 mHz frequency range, and phase speeds 1-3 Mm/s. The wave trajectories are consistent with the direction of the magnetic field inferred from the linear polarization measurements. We discuss the phase and coherence of these waves as a function of height in the corona and relate our findings to previous observations. The observed waves appear to be Alfvenic in character. "Thomas Schad was supported through the National Solar Observatory Research Experiences for Undergraduate (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program." Daniel Seeley was supported through the National Solar Observatory Research Experience for Teachers (RET) site program, which is funded by the National Science Foundation RET program.

  19. Seismological Constraints on Lithospheric Evolution in the Appalachian Orogen

    Science.gov (United States)

    Fischer, K. M.; Hopper, E.; Hawman, R. B.; Wagner, L. S.

    2017-12-01

    Crust and mantle structures beneath the Appalachian orogen, recently resolved by seismic data from the EarthScope SESAME Flexible Array and Transportable Array, provide new constraints on the scale and style of the Appalachian collision and subsequent lithospheric evolution. In the southern Appalachians, imaging with Sp and Ps phases reveals the final (Alleghanian) suture between the crusts of Laurentia and the Gondwanan Suwannee terrane as a low angle (Kellogg, 2017) isostatic arguments indicate crustal thicknesses were 15-25 km larger at the end of the orogeny, indicating a thick crustal root across the region. The present-day residual crustal root beneath the Blue Ridge mountains is estimated to have a density contrast with the mantle of only 104±20 kg/m3. This value is comparable to other old orogens but lower than values typical of young or active orogens, indicating a loss of lower crustal buoyancy over time. At mantle depths, the negative shear velocity gradient that marks the transition from lithosphere to asthenosphere, as illuminated by Sp phases, varies across the Appalachian orogen. This boundary is shallow beneath the northeastern U.S. and in the zone of Eocene volcanism in Virginia, where low velocity anomalies occur in the upper mantle. These correlations suggest recent active lithosphere-asthenosphere interaction.

  20. Seismological investigation of the National Data Centre Preparedness Exercise 2013

    Science.gov (United States)

    Gestermann, Nicolai; Hartmann, Gernot; Ross, J. Ole; Ceranna, Lars

    2015-04-01

    The Comprehensive Nuclear-Test-Ban Treaty (CTBT) prohibits all kinds of nuclear explosions conducted on Earth - underground, underwater or in the atmosphere. The verification regime of the CTBT is designed to detect any treaty violation. While the data of the International Monitoring System (IMS) is collected, processed and technically analyzed at the International Data Centre (IDC) of the CTBT-Organization, National Data Centres (NDC) of the member states provide interpretation and advice to their government concerning suspicious detections. The NDC Preparedness Exercises (NPE) are regularly performed dealing with fictitious treaty violations to practice the combined analysis of CTBT verification technologies. These exercises should help to evaluate the effectiveness of analysis procedures applied at NDCs and the quality, completeness and usefulness of IDC products for example. The exercise trigger of NPE2013 is a combination of a tempo-spatial indication pointing to a certain waveform event and simulated radionuclide concentrations generated by forward Atmospheric Transport Modelling based on a fictitious release. For the waveform event the date (4 Sept. 2013) is given and the region is communicated in a map showing the fictitious state of "Frisia" at the Coast of the North Sea in Central Europe. The potential connection between the waveform and radionuclide evidence remains unclear for exercise participants. The verification task was to identify the waveform event and to investigate potential sources of the radionuclide findings. The final question was whether the findings are CTBT relevant and justify a request for On-Site-Inspection in "Frisia". The seismic event was not included in the Reviewed Event Bulletin (REB) of the IDC. The available detections from the closest seismic IMS stations lead to a epicenter accuracy of about 24 km which is not sufficient to specify the 1000 km2 inspection area in case of an OSI. With use of data from local stations and adjusted velocity models the epicenter accuracy could be improved to less than 2 km, which demonstrates the crucial role of national technical means for verification tasks. The seismic NPE2013 event could be identified as induced from natural gas production in the source region. Similar waveforms and comparable spectral characteristic as a set of events in the same region are clear indications. The scenario of a possible treaty violation at the location of the seismic NPE2013 event could be disproved.

  1. Magnetic seismology of interstellar gas clouds: Unveiling a hidden dimension.

    Science.gov (United States)

    Tritsis, Aris; Tassis, Konstantinos

    2018-05-11

    Stars and planets are formed inside dense interstellar molecular clouds by processes imprinted on the three-dimensional (3D) morphology of the clouds. Determining the 3D structure of interstellar clouds remains challenging because of projection effects and difficulties measuring the extent of the clouds along the line of sight. We report the detection of normal vibrational modes in the isolated interstellar cloud Musca, allowing determination of the 3D physical dimensions of the cloud. We found that Musca is vibrating globally, with the characteristic modes of a sheet viewed edge on, not the characteristics of a filament as previously supposed. We reconstructed the physical properties of Musca through 3D magnetohydrodynamic simulations, reproducing the observed normal modes and confirming a sheetlike morphology. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  2. Glacier seismology: eavesdropping on the ice-bed interface

    Science.gov (United States)

    Walter, F.; Röösli, C.

    2015-12-01

    Glacier sliding plays a central role in ice dynamics. A number of remote sensing and deep drilling initiatives have therefore focused on the ice-bed interface. Although these techniques have provided valuable insights into bed properties, they do not supply theorists with data of sufficient temporal and spatial resolution to rigorously test mathematical sliding laws. As an alternative, passive seismic techniques have gained popularity in glacier monitoring. Analysis of glacier-related seismic sources ('icequakes') has become a useful technique to study inaccessible regions of the cryosphere, including the ice-bed interface. Seismic monitoring networks on the polar ice sheets have shown that ice sliding is not only a smooth process involving viscous deformation and regelation of basal ice layers. Instead, ice streams exhibit sudden slip episodes over their beds and intermittent phases of partial or complete stagnation. Here we discuss new and recently published discoveries of basal seismic sources beneath various glacial bodies. We revisit basal seismicity of hard-bedded Alpine glaciers, which is not the result of pure stick-slip motion. Sudden changes in seismicity suggest that the local configuration of the subglacial drainage system undergoes changes on sub daily time scales. Accordingly, such observations place constraints on basal resistance and sliding of hard-bedded glaciers. In contrast, certain clusters of stick-slip dislocations associated with micro seismicity beneath the Greenland ice sheet undergo diurnal variations in magnitudes and inter event times. This is best explained with a soft till bed, which hosts the shear dislocations and whose strength varies in response to changes in subglacial water pressure. These results suggest that analysis of basal icequakes is well suited for characterizing glacier and ice sheet beds. Future studies should address the relative importance between "smooth" and seismogenic sliding in different glacial environments.

  3. Seismological analysis of the fourth North Korean nuclear test

    Science.gov (United States)

    Hartmann, Gernot; Gestermann, Nicolai; Ceranna, Lars

    2016-04-01

    The Democratic People's Republic of Korea has conducted its fourth underground nuclear explosions on 06.01.2016 at 01:30 (UTC). The explosion was clearly detected and located by the seismic network of the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Additional seismic stations of international earthquake monitoring networks at regional distances, which are not part of the IMS, are used to precisely estimate the epicenter of the event in the North Hamgyong province (41.38°N / 129.05°E). It is located in the area of the North Korean Punggye-ri nuclear test site, where the verified nuclear tests from 2006, 2009, and 2013 were conducted as well. The analysis of the recorded seismic signals provides the evidence, that the event was originated by an explosive source. The amplitudes as well as the spectral characteristics of the signals were examined. Furthermore, the similarity of the signals with those from the three former nuclear tests suggests very similar source type. The seismograms at the 8,200 km distant IMS station GERES in Germany, for example, show the same P phase signal for all four explosions, differing in the amplitude only. The comparison of the measured amplitudes results in the increasing magnitude with the chronology of the explosions from 2006 (mb 4.2), 2009 (mb 4.8) until 2013 (mb 5.1), whereas the explosion in 2016 had approximately the same magnitude as that one three years before. Derived from the magnitude, a yield of 14 kt TNT equivalents was estimated for both explosions in 2013 and 2016; in 2006 and 2009 yields were 0.7 kt and 5.4 kt, respectively. However, a large inherent uncertainty for these values has to be taken into account. The estimation of the absolute yield of the explosions depends very much on the local geological situation and the degree of decoupling of the explosive from the surrounding rock. Due to the missing corresponding information, reliable magnitude-yield estimation for the North Korean test site is proved to be difficult. The direct evidence for the nuclear character of the explosion can only be found, if radioactive fission products of the explosion get released into the atmosphere and detected. The corresponding analysis by Atmospheric Transport Modelling is presented on the poster by O. Ross and L. Ceranna assessing the detection chances of IMS radionuclide stations.

  4. Seismological analysis of group pile foundation for reactor

    International Nuclear Information System (INIS)

    Wang Demin.

    1984-01-01

    In the seismic analysis for reactor foundation of nuclear power plant, the local raise of base mat is of great significance. Base on the study of static and dynamic stability as well as soil-structure interaction of group piles on stratified soil, this paper presents a method of seismic analysis for group piles of reactor foundation at abroad, and a case history is enclosed. (Author)

  5. Progress of the seismological program in El Salvador

    Science.gov (United States)

    Martinez, M. A.

    1982-01-01

     El Salvador is located in Central America at the axis of geographical coordinates 14° north latitude and 89° west longitude. Situated inside the circumpacific "ring of fire" it is thus vulnerable to sudden earthquakes and volcanic eruptions. 

  6. Seismological investigation of earthquakes in the New Madrid Seismic Zone

    International Nuclear Information System (INIS)

    Herrmann, R.B.; Nguyen, B.

    1993-08-01

    Earthquake activity in the New Madrid Seismic Zone had been monitored by regional seismic networks since 1975. During this time period, over 3,700 earthquakes have been located within the region bounded by latitudes 35 degrees--39 degrees N and longitudes 87 degrees--92 degrees W. Most of these earthquakes occur within a 1.5 degrees x 2 degrees zone centered on the Missouri Bootheel. Source parameters of larger earthquakes in the zone and in eastern North America are determined using surface-wave spectral amplitudes and broadband waveforms for the purpose of determining the focal mechanism, source depth and seismic moment. Waveform modeling of broadband data is shown to be a powerful tool in defining these source parameters when used complementary with regional seismic network data, and in addition, in verifying the correctness of previously published focal mechanism solutions

  7. Supernova seismology: gravitational wave signatures of rapidly rotating core collapse

    Science.gov (United States)

    Fuller, Jim; Klion, Hannah; Abdikamalov, Ernazar; Ott, Christian D.

    2015-06-01

    Gravitational waves (GW) generated during a core-collapse supernova open a window into the heart of the explosion. At core bounce, progenitors with rapid core rotation rates exhibit a characteristic GW signal which can be used to constrain the properties of the core of the progenitor star. We investigate the dynamics of rapidly rotating core collapse, focusing on hydrodynamic waves generated by the core bounce, and the GW spectrum they produce. The centrifugal distortion of the rapidly rotating proto-neutron star (PNS) leads to the generation of axisymmetric quadrupolar oscillations within the PNS and surrounding envelope. Using linear perturbation theory, we estimate the frequencies, amplitudes, damping times, and GW spectra of the oscillations. Our analysis provides a qualitative explanation for several features of the GW spectrum and shows reasonable agreement with non-linear hydrodynamic simulations, although a few discrepancies due to non-linear/rotational effects are evident. The dominant early post-bounce GW signal is produced by the fundamental quadrupolar oscillation mode of the PNS, at a frequency 0.70 ≲ f ≲ 0.80 kHz, whose energy is largely trapped within the PNS and leaks out on a ˜10-ms time-scale. Quasi-radial oscillations are not trapped within the PNS and quickly propagate outwards until they steepen into shocks. Both the PNS structure and Coriolis/centrifugal forces have a strong impact on the GW spectrum, and a detection of the GW signal can therefore be used to constrain progenitor properties.

  8. Seismological evidence for a localized mushy zone at the Earth?s inner core boundary

    OpenAIRE

    Tian, Dongdong; Wen, Lianxing

    2017-01-01

    Although existence of a mushy zone in the Earth?s inner core has been hypothesized several decades ago, no seismic evidence has ever been reported. Based on waveform modeling of seismic compressional waves that are reflected off the Earth?s inner core boundary, here we present seismic evidence for a localized 4?8?km thick zone across the inner core boundary beneath southwest Okhotsk Sea with seismic properties intermediate between those of the inner and outer core and of a mushy zone. Such a ...

  9. NetQuakes - A new approach to urban strong-motion seismology

    Science.gov (United States)

    Luetgert, J. H.; Evans, J. R.; Hamilton, J.; Hutt, C. R.; Jensen, E. G.; Oppenheimer, D. H.

    2009-12-01

    There is a recognized need for more densely sampled strong ground motion recordings in urban areas to provide more accurate ShakeMaps for post-earthquake disaster assessment and to provide data for structural engineers to improve design standards. Ideally, the San Francisco Bay area would have a strong ground motion recorder every 1-2 km to adequately sample the region’s varied geology and built environment. This would require the addition of thousands of instruments to the existing network. There are several fiscal and logistical constraints that prevent us from doing this with traditional strong motion instrumentation and telemetry. In addition to the initial expense of instruments and their installation, there are the continuing costs of telemetry and maintenance. To address these issues, the USGS implemented the NetQuakes project to deploy small, relatively inexpensive seismographs for installation in 1-2 story homes and businesses that utilize the host’s existing Internet connection. The recorder has 18 bit resolution with ±3g internal tri-axial MEMS accelerometers. Data is continuously recorded at 200 sps into a 1-2 week ringbuffer. When triggered, a miniSEED file is sent to USGS servers via the Internet. Data can also be recovered from the ringbuffer by a remote request through the servers. Following a power failure, the instrument can run for 36 hours using its internal battery. All client-server interactions are initiated by the instrument, so it safely resides behind a host’s firewall. Instrument and battery replacement can be performed by hosts to reduce maintenance costs. A connection to the host’s LAN, and thence to the public Internet, can be made using WiFi to minimize cabling. Although timing via a cable to an external GPS antenna is possible, it is simpler to use the Network Time Protocol (NTP) to synchronize the internal clock. NTP achieves timing accuracy generally better than a sample interval. Since February, 2009, we have installed more than 60 NetQuakes instruments in the San Francisco Bay Area and have successfully integrated their data into the near real time data stream of the Northern California Seismic System.

  10. Seismological observations at discrete sites during the seismic experiment Sudetes 2003

    Czech Academy of Sciences Publication Activity Database

    Holub, Karel; Knejzlík, Jaromír; Rušajová, Jana

    2005-01-01

    Roč. 5, č. 2 (2005), s. 45-52 ISSN 1213-1962 R&D Projects: GA ČR(CZ) GA205/03/0999 Institutional research plan: CEZ:AV0Z30860518 Keywords : seismic experiment * Sudetes 2003 Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  11. Seismic anisotropy of the mantle lithosphere beneath the Swedish National Seismological Network (SNSN)

    Czech Academy of Sciences Publication Activity Database

    Eken, T.; Plomerová, Jaroslava; Roberts, R.; Vecsey, Luděk; Babuška, Vladislav; Shomali, H.; Bodvarsson, R.

    2010-01-01

    Roč. 480, č. 1-4 (2010), s. 241-258 ISSN 0040-1951 R&D Projects: GA AV ČR IAA300120709; GA AV ČR(CZ) KJB300120605 Institutional research plan: CEZ:AV0Z30120515 Keywords : Baltic Shield * mantle lithosphere * seismic anisotropy * domains and their boundaries in the mantle Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.509, year: 2010

  12. Geological-Seismological Evaluation of Earthquake Hazards at West Thompson Damsite, Connecticut.

    Science.gov (United States)

    1984-06-01

    Connecticut, N of 41.61N 72.12W 1.5 - Norwich ( Foreshock ) 29 Jun 80 Connecticut, N of 41.46N 72.09W 1.8 - Norwich 28 Jul 80 Connecticut, N of 41.52N...the event was judged to be either an aftershock or foreshock ; the geographic location is given as north latitude and west longitude, to the nearest 0.10

  13. Proceedings. first assembly of the latin-america and caribbean seismological commission - lacsc

    OpenAIRE

    Third Latin-American Congress of Seismology, Third Latin-American Congress of Seismol

    2014-01-01

    The Latin-American and Caribbean region is an area with a very complex tectonic setting, where stress and strain generated by the interaction of several lithospheric plates is being absorbed. Several regional fault systems, with moderate and high activity, represent a hazard for a significant part of the population (more than 500 million inhabitants). Given the recent developments in the mining and energy industries, a great deal of exploration has been focusing on this part of the world, and...

  14. Proceedings. First Assembly of the Latin-America and Caribbean Seismological Commission - LACSC

    Directory of Open Access Journals (Sweden)

    Third Latin-American Congress of Seismol Third Latin-American Congress of Seismology

    2014-02-01

    Full Text Available The Latin-American and Caribbean region is an area with a very complex tectonic setting, where stress and strain generated by the interaction of several lithospheric plates is being absorbed. Several regional fault systems, with moderate and high activity, represent a hazard for a significant part of the population (more than 500 million inhabitants. Given the recent developments in the mining and energy industries, a great deal of exploration has been focusing on this part of the world, and the potential extraction of mineral resources is going to generate important changes in vast areas of the American continent. Considering the geodynamic framework and the expectation of the extraction of economic resources, questions about the impact of human activities and the possible destabilizing of the relevant tectonic systems are raised. Many theoretical and applied geophysical studies have been developed in different regions of Latin-America and the Caribbean, mainly since the second half of the 20th century. There have been basically two motivations to carry out these studies: The evaluation of natural hazards and the exploration of economic resources. Such studies have mainly focused on the knowledge of: (a the structure of the crust and upper mantle, (b the regional tectonic evolution, (c the local and regional seismic hazards, and (d the geometry of geologic structures of economic interest. This part of the world has witnessed an excessive and disproportionate growth in the number of urban centers, evidenced by the increase in economic and social gaps. This situation puts a great portion of the population at a high level of vulnerability, which in addition to the natural hazard in the region, configures a scenario of high seismic risk. In this academic event, the relevant results associated with the seismotectonic behavior of this part of the world will be addressed, as well as the implications of active exploration of the tectonic conditions, the socio-economic impacts of exploration and extraction of economic resources, and the implementation of non-conventional techniques for exploring and mining that can contribute to sustainable development. We welcome contributions from around the world.

  15. Actions at Hamburg International Association of Seismology and Physics of the Earth's Interior

    Science.gov (United States)

    The third Workshop on Historical Seismograms, held in Hamburg on August 18-19, 1983, in conjunction with the meeting of the International Union of Geodesy and Geophysics in Hamburg, Federal Republic of Germany, was specifically organized to discuss the status of historical seismic data for Latin America and Europe. Since it is unlikely that an additional workshop will be held on this subject, reports for other regions were included as well.In the first session, H. Meyers described the purpose of the workshop and gave some history of the previous activities of the IASPEI/Unesco Working Group on Historical Seismograms. E.R. Engdahl noted that thus far more than 500,000 seismograms have been filmed as part of the Historical Microfilming Project and emphasized the importance of the activities to be covered during the workshop. M. Hashizume, representing Unesco, described the importance of historical seismic data and the Unesco interests in having these data available for the analysis of seismic risks, particularly in areas where the recurrence rate of significant earthquakes is very low and for regions where much data do not exist. He mentioned that both these conditions occur frequently in developing nations.

  16. A seismological overview of the induced earthquakes in the Duvernay play near Fox Creek, Alberta

    Science.gov (United States)

    Schultz, Ryan; Wang, Ruijia; Gu, Yu Jeffrey; Haug, Kristine; Atkinson, Gail

    2017-01-01

    This paper summarizes the current state of understanding regarding the induced seismicity in connection with hydraulic fracturing operations targeting the Duvernay Formation in central Alberta, near the town of Fox Creek. We demonstrate that earthquakes in this region cluster into distinct sequences in time, space, and focal mechanism using (i) cross-correlation detection methods to delineate transient temporal relationships, (ii) double-difference relocations to confirm spatial clustering, and (iii) moment tensor solutions to assess fault motion consistency. The spatiotemporal clustering of the earthquake sequences is strongly related to the nearby hydraulic fracturing operations. In addition, we identify a preference for strike-slip motions on subvertical faults with an approximate 45° P axis orientation, consistent with expectation from the ambient stress field. The hypocentral geometries for two of the largest-magnitude (M 4) sequences that are robustly constrained by local array data provide compelling evidence for planar features starting at Duvernay Formation depths and extending into the shallow Precambrian basement. We interpret these lineaments as subvertical faults orientated approximately north-south, consistent with the regional moment tensor solutions. Finally, we conclude that the sequences were triggered by pore pressure increases in response to hydraulic fracturing stimulations along previously existing faults.

  17. AfricaArray seismological studies of the structure and evolution of the African continent

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-10-01

    Full Text Available and Madagascar. Brandt and Mulibo elucidated the relationship between the African Superplume, Superswell and the East African Rift System by studying the seismic velocity structure of the mantle. Kgaswane jointly inverted P-wave receiver functions (PRFs...

  18. Integration of onshore and offshore seismological data to study the seismicity of the Calabrian Region

    Science.gov (United States)

    D'Alessandro, Antonino; Guerra, Ignazio; D'Anna, Giuseppe; Gervasi, Anna; Harabaglia, Paolo; Luzio, Dario; Stellato, Gilda

    2014-05-01

    The Pollino Massif marks the transition from the Southern Appenninic to the Calabrian Arc. On the western side it is characterized by a moderately sized seismicity (about 9 M > 4 events in the last 50 years), well documented in the last 400 years. The moment tensor solutions available in this area yields, mainly, normal faults with coherent Southern Appeninic trend. This remains true also for the events that are localized on the calabrian side of Pollino, South of the massif. In most of the Sibari plane, seismic activity is very scarce, while it is again rather marked on its southeastern corner, both onshore and offshore. The above observations point to the perspective that the stress field of a vast portion of Northern Calabria still resembles that of the Southern Appenines. In this frame, it becomes important to investigate the offshore seismicity of the Sibari Gulf and the deformation pattern within the Sibari Plane. The latter might function as a hinge to transfer the deformation of the extensional fault system in the Pollino area to a different offshore fault system. Since return times of larger events might be very long, we need to investigate the true seismic potential of the offshore faults and to verify whether they are truly strike slip or if they could involve relevant thrust or normal components, that would add to the risk that of potentially associated tsunamis. Despite their importance in the understanding of the seismotectonic processes taking place in the Southern Appenninic - Calabrian Arc border and surrounding areas, the seismicity and the seismogenic volumes of the Sibari Gulf until now has not been well characterized due to the lack of offshore seismic stations. The seismicity of the Calabrian is monitored by the Italian National Seismic Network (INSN) managed by Istituto Nazionale di Geofisica e Vulcanologia and by the Calabrian Regional Seismic Network (CRSN) managed by the University of Calabria. Both the network comprise only on-land seismic stations. The lack of offshore stations prevents accurate determination of the hypocentral parameters also for moderate-strong earthquakes that occur in the Calabria offshore. With the aim of investigate the near shore seismicity in the Sibari Gulf and its eventual relationship with the Pollino activity, in the early 2014 will start a project for the improvement of the Calabrian Seismic Network in monitoring the Sibari Gulf area by deploying several Ocean Bottom Seismometers with Hydrophone (OBS/H). For this experiment, each OBS/H is equipped with a broad-band seismometer housed in a glass sphere designed to operate at a depth of up to 6000 m and with an autolevelling sensor system. The OBS/Hs are also equipped with an hydrophone. Analogical signals are recorded with a sampling frequency of 200 Hz by a four-channel 21 bits datalogger. In this work, we plan to present the preliminary results of the monitoring campaign showing the largest improvement in hypocenter locations derived from the integration of the onshore and offshore seismic stations.

  19. The Quake-Catcher Network: Bringing Seismology to Homes and Schools

    Science.gov (United States)

    Lawrence, J. F.; Cochran, E. S.; Christensen, C. M.; Saltzman, J.; Taber, J.; Hubenthal, M.

    2011-12-01

    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 Quake-Catcher Network 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. With greater understanding, teachers, students, and interested individuals can share their new knowledge, resulting in continued participation in the project, and better preparation for earthquakes in their homes, businesses, and communities. The primary educational outreach goals are 1) to present earthquake science and earthquake hazards in a modern and exciting way, and 2) to provide teachers and educators with seismic sensors, interactive software, and educational modules to assist in earthquake education. QCNLive (our interactive educational computer software) displays recent and historic earthquake locations and 3-axis real-time acceleration measurements. This tool is useful for demonstrations and active engagement for all ages, from K-college. QCN provides subsidized sensors at 49 for the general public and 5 for K-12 teachers. With your help, the Quake-Catcher Network can provide better understanding of earthquakes to a broader audience. Academics are taking QCN to classrooms across the United States and around the world. The next time you visit a K-12 classroom or teach a college class on interpreting seismograms, bring a QCN sensor and QCNLive software with you! To learn how, visit http://qcn.stanford.edu.

  20. Crustal structure and evolution of the Arctic Caledonides: Results from controlled-source seismology

    Science.gov (United States)

    Aarseth, Iselin; Mjelde, Rolf; Breivik, Asbjørn Johan; Minakov, Alexander; Faleide, Jan Inge; Flueh, Ernst; Huismans, Ritske S.

    2017-10-01

    The continuation of the Caledonides into the Barents Sea has long been a subject of discussion, and two major orientations of the Caledonian deformation fronts have been suggested: NNW-SSE striking and NE-SW striking. A regional NW-SE oriented ocean bottom seismic profile across the western Barents Sea was acquired in 2014. In this paper we map the crust and upper mantle structure along this profile in order to discriminate between different interpretations of Caledonian structural trends and orientation of rift basins in the western Barents Sea. Modeling of P-wave travel times has been done using a ray-tracing method, and combined with gravity modeling. The results show high P-wave velocities (4 km/s) close to the seafloor, as well as localized sub-horizontal high velocity zones (6.0 km/s and 6.9 km/s) at shallow depths which are interpreted as magmatic sills. Refractions from the top of the crystalline basement together with reflections from the Moho give basement velocities from 6.0 km/s at the top to 6.7 km/s at the base of the crust. P-wave travel time modeling of the OBS profile indicate an eastwards increase in velocities from 6.4 km/s to 6.7 km/s at the base of the crystalline crust, and the western part of the profile is characterized by a higher seismic reflectivity than the eastern part. This change in seismic character is consistent with observations from vintage reflection seismic data and is interpreted as a Caledonian suture extending through the Barents Sea, separating Barentsia and Baltica. Local deepening of Moho (from 27 km to 33 km depth) creates ;root structures; that can be linked to the Caledonian compressional deformation or a suture zone imprinted in the lower crust. Our model supports a separate NE-SW Caledonian trend extending into the central Barents Sea, branching off from the northerly trending Svalbard Caledonides, implying the existence of Barentsia as an independent microcontinent between Laurentia and Baltica.

  1. Seismological evidence for a sub-volcanic arc mantle wedge beneath the Denali volcanic gap, Alaska

    Science.gov (United States)

    McNamara, D.E.; Pasyanos, M.E.

    2002-01-01

    Arc volcanism in Alaska is strongly correlated with the 100 km depth contour of the western Aluetian Wadati-Benioff zone. Above the eastern portion of the Wadati-Benioff zone however, there is a distinct lack of volcanism (the Denali volcanic gap). We observe high Poisson's ratio values (0.29-0.33) over the entire length of the Alaskan subduction zone mantle wedge based on regional variations of Pn and Sn velocities. High Poisson's ratios at this depth (40-70 km), adjacent to the subducting slab, are attributed to melting of mantle-wedge peridotites, caused by fluids liberated from the subducting oceanic crust and sediments. Observations of high values of Poisson's ratio, beneath the Denali volcanic gap suggest that the mantle wedge contains melted material that is unable to reach the surface. We suggest that its inability to migrate through the overlying crust is due to increased compression in the crust at the northern apex of the curved Denali fault.

  2. Dynamical links between small- and large-scale mantle heterogeneity: Seismological evidence

    Science.gov (United States)

    Frost, Daniel A.; Garnero, Edward J.; Rost, Sebastian

    2018-01-01

    We identify PKP • PKP scattered waves (also known as P‧ •P‧) from earthquakes recorded at small-aperture seismic arrays at distances less than 65°. P‧ •P‧ energy travels as a PKP wave through the core, up into the mantle, then scatters back down through the core to the receiver as a second PKP. P‧ •P‧ waves are unique in that they allow scattering heterogeneities throughout the mantle to be imaged. We use array-processing methods to amplify low amplitude, coherent scattered energy signals and resolve their incoming direction. We deterministically map scattering heterogeneity locations from the core-mantle boundary to the surface. We use an extensive dataset with sensitivity to a large volume of the mantle and a location method allowing us to resolve and map more heterogeneities than have previously been possible, representing a significant increase in our understanding of small-scale structure within the mantle. Our results demonstrate that the distribution of scattering heterogeneities varies both radially and laterally. Scattering is most abundant in the uppermost and lowermost mantle, and a minimum in the mid-mantle, resembling the radial distribution of tomographically derived whole-mantle velocity heterogeneity. We investigate the spatial correlation of scattering heterogeneities with large-scale tomographic velocities, lateral velocity gradients, the locations of deep-seated hotspots and subducted slabs. In the lowermost 1500 km of the mantle, small-scale heterogeneities correlate with regions of low seismic velocity, high lateral seismic gradient, and proximity to hotspots. In the upper 1000 km of the mantle there is no significant correlation between scattering heterogeneity location and subducted slabs. Between 600 and 900 km depth, scattering heterogeneities are more common in the regions most remote from slabs, and close to hotspots. Scattering heterogeneities show an affinity for regions close to slabs within the upper 200 km of the mantle. The similarity between the distribution of large-scale and small-scale mantle structures suggests a dynamic connection across scales, whereby mantle heterogeneities of all sizes may be directed in similar ways by large-scale convective currents.

  3. Relationship between the rock mass deformation and places of occurrence of seismological events

    Energy Technology Data Exchange (ETDEWEB)

    Janusz Makowka; Jozef Kabiesz; Lin-ming Ddou [Central Mining Institute, Katowice (Poland)

    2009-09-15

    Static effort of rock mass very rarely causes of rock burst in Polish coal mines. Rock bursts with source in the seismic tremor within the roof rock layers are prevailing. A seismic tremor is an effect of rupture or sliding in roof layers above the exploited panel in coal seam, sometime in a distance from actual exploitation. Sliding, as a rule occurs in fault zone and tremors in it are expected, but monolithic layer rupture is very hard to predict. In a past few years a practice of analyzing state of deformation in high energy seismic tremors zones has been employed. It let gathering experience thanks to witch determination of dangerous shape of reformatted roof is possible. In the paper some typical forms of roof rocks deformations leading to seismic tremor occurrence will be presented. In general these are various types of multidirectional rock layers bending. Real examples of seismic events and rock bursts in the Czech Republic will be shown. 5 refs., 6 figs.

  4. A first near real-time seismology-based landquake monitoring system.

    Science.gov (United States)

    Chao, Wei-An; Wu, Yih-Min; Zhao, Li; Chen, Hongey; Chen, Yue-Gau; Chang, Jui-Ming; Lin, Che-Min

    2017-03-02

    Hazards from gravity-driven instabilities on hillslope (termed 'landquake' in this study) are an important problem facing us today. Rapid detection of landquake events is crucial for hazard mitigation and emergency response. Based on the real-time broadband data in Taiwan, we have developed a near real-time landquake monitoring system, which is a fully automatic process based on waveform inversion that yields source information (e.g., location and mechanism) and identifies the landquake source by examining waveform fitness for different types of source mechanisms. This system has been successfully tested offline using seismic records during the passage of the 2009 Typhoon Morakot in Taiwan and has been in online operation during the typhoon season in 2015. In practice, certain levels of station coverage (station gap 10 6  m 3 and area > 0.20 km 2 ) are required to ensure good performance (fitness > 0.6 for successful source identification) of the system, which can be readily implemented in other places in the world with real-time seismic networks and high landquake activities.

  5. Geology, hydrology, seismology and geotechnique of Al-Jafra site (NORM remediation project)

    International Nuclear Information System (INIS)

    Redwan, Y.; Abou Zakhem, B; Sbeinati, R.; Moussa, A. M.

    2002-07-01

    The Jafra field site is located 35 km to the E-SE of Deir Ezzor Town (east Syria). The prevailing climate is characterized by cold winter (1.8?) and hot summer (39?) with an average rainfall of 144 mm/y. Annual evaporation rate reaches 214 mm/y and strong seasonal wind hits the area in autumn and spring. From geologic and tectonic point of view the Jafra Field Site is situated within Deir Ezzor Depression to the east of the intersection of the SE/ESE trending Euphratean Fault with the NE trending Southern Palymrean Faulting Zone. At the site, horizontal or westwards gently dipping Pliocene gypsum and clayey sediments outcrop. Q3 volcanism ascended through NNE faults covering a vast area. Pliocene gypsum suffer from deep weathering due to high solubility. Physical properties of the rocks exposed in Jafra Oil Field Site were estimated. It is recommended to take them seriously in consideration in designing and construction any future facility. Hydrologically, Lower Pliocene aquifer is composed of conglomerate, gravels and sands. It is fed by lateral infiltration from Euphrates. Shallow water bearing level is found at 20-30 m while a second one lies at 80-90 m. A soil profile was drilled to depth 2.5 m and the mineralogy of the soil was found to be prevailed mainly by gypsum and clay. Water chemical composition and salinity were defined. Seismic hazard of the site was assessed and found that NW-SE Euphrates Faults System and Al Bishri Fault govern the site's seismicity. Three historical earthquakes namely 160 Ad, 8th century Ad and 859-860 Ad hit the Jafra Oil Field Site area. Eighteen earthquakes of magnitudes vary between 4.1 and 5.5 during the time interval extends from 1900-1994 struck the area. A 1- Hz natural period and one vertical component portable seismic station has been installed in the field for two months. It monitored 13 events the strongest of which had a Md = 4.7 located 320 km from the site. The site was given an intensity of III degrees on (EMS-92) scale. The domain event magnitudes were Md = 1.8-2.2 distanced 16 km from the site. A seismic activity of the Euphrates Fault Zone is evident and may be triggered by oil exploration or injection in productive wells. Some sites in Al Jafra Oil Field Site have been defined by AECS experts as contaminated by surface and deep distributions of Radium 226. The second recommendation of the SAEC experts report on Al Jafra oil fields suggested designing a disposal pit to accommodate 3161 m3 of contaminated soil derived from the mud pit, surface water pit and from the run-off channel. Through this study a site for such a pit is expected to be located to the south of the surface water pit east of the run-off channel outside the Jafra Oil Field Site fence. A detailed engineering construction of disposal pit was presented taking in consideration geological and hydrological aspects of the area. Long-term performance requirements of NORM-disposal facility during and after construction of the pit were highlighted and recommended. (author)

  6. InSight: Single Station Broadband Seismology for Probing Mars' Interior

    Science.gov (United States)

    Panning, Mark P.; Banerdt, W. Bruce; Beucler, Eric; Boschi, Lapo; Johnson, Catherine; Lognonne, Philippe; Mocquet, Antoine; Weber, Renee C.

    2012-01-01

    InSight is a proposed Discovery mission which will deliver a lander containing geophysical instrumentation, including a heat flow probe and a seismometer package, to Mars. The aim of this mission is to perform, for the first time, an in-situ investigation of the interior of a truly Earth- like planet other than our own, with the goal of understanding the formation and evolution of terrestrial planets through investigation of the interior structure and processes of Mars.

  7. Broadband seismic noise attenuation versus depth at the Albuquerque Seismological Laboratory

    Science.gov (United States)

    Hutt, Charles R.; Ringler, Adam; Gee, Lind

    2017-01-01

    Seismic noise induced by atmospheric processes such as wind and pressure changes can be a major contributor to the background noise observed in many seismograph stations, especially those installed at or near the surface. Cultural noise such as vehicle traffic or nearby buildings with air handling equipment also contributes to seismic background noise. Such noise sources fundamentally limit our ability to resolve earthquake‐generated signals. Many previous seismic noise versus depth studies focused separately on either high‐frequency (>1  Hz">>1  Hz) or low‐frequency (shallow surface vaults) up to 100 m or more (boreholes) in the permanent observatories of the Global Seismographic Network (GSN). It is important for managers and planners of these and similar arrays and networks of seismograph stations to understand the attenuation of surface‐generated noise versus depth so that they can achieve desired performance goals within their budgets as well as their frequency band of focus. The results of this study will assist in decisions regarding BB and VBB seismometer installation depths. In general, we find that greater installation depths are better and seismometer emplacement in hard rock is better than in soil. Attenuation for any given depth varies with frequency. More specifically, we find that the dependence of depth will be application dependent based on the frequency band and sensitive axes of interest. For quick deployments (like aftershock studies), 1 m may be deep enough to produce good data, especially when the focus is on vertical data where temperature stability fundamentally limits the low‐frequency noise levels and little low‐frequency data will be used. For temporary (medium‐term) deployments (e.g., TA) where low cost can be very important, 2–3 m should be sufficient, but such shallow installations will limit the ability to resolve low‐frequency signals, especially on horizontal components. Of course, one should try for maximum burial depth within the budget when there is interest in using the data for low‐frequency applications. For long‐term deployments like the permanent observatories of the GSN and similar networks, 100–200 m depth in hard rock is desirable to achieve lowest noise, although 30–60 m may be acceptable.

  8. Prospects for Jovian seismological observations following the impact of comet Shoemaker-Levy 9

    Science.gov (United States)

    Deming, Drake

    1994-01-01

    The impact of each fragment of comet SL-9 will produce a downward-propagating pressure wave which will travel at the sound speed through the jovian interior. Since the sound speed increases with depth, most of the energy in the pressure pulse will be strongly refracted and return to the surface, as recently computed by Marley (1994). This wave may in principle be observable as it propagates into the stratosphere, using sufficiently sensitive thermal infrared imaging. If so, it will provide a unique opportunity to constrain models of the jovian interior. This paper extends Marley's calculations to include the effect of the limited spatial resolution which will be characteristic of real observations. The wave pattern on the disk will consist of closely spaced regions of alternating temperature increases and decreases. Spatial averaging will significantly reduce the observed amplitude for resolutions attainable using earth-based telescopes, but the waves should remain above the detection limit.

  9. UNRAVELLING THE COMPONENTS OF A MULTI-THERMAL CORONAL LOOP USING MAGNETOHYDRODYNAMIC SEISMOLOGY

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, S. Krishna; Jess, D. B. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN (United Kingdom); Klimchuk, J. A. [Heliophysics Division, NASA Goddard Space Flight Center, Greenbelt, MD, 20771 (United States); Banerjee, D., E-mail: krishna.prasad@qub.ac.uk [Indian Institute of Astrophysics, II Block Koramangala, Bengaluru 560034 (India)

    2017-01-10

    Coronal loops, constituting the basic building blocks of the active Sun, serve as primary targets to help understand the mechanisms responsible for maintaining multi-million Kelvin temperatures in the solar and stellar coronae. Despite significant advances in observations and theory, our knowledge on the fundamental properties of these structures is limited. Here, we present unprecedented observations of accelerating slow magnetoacoustic waves along a coronal loop that show differential propagation speeds in two distinct temperature channels, revealing the multi-stranded and multithermal nature of the loop. Utilizing the observed speeds and employing nonlinear force-free magnetic field extrapolations, we derive the actual temperature variation along the loop in both channels, and thus are able to resolve two individual components of the multithermal loop for the first time. The obtained positive temperature gradients indicate uniform heating along the loop, rather than isolated footpoint heating.

  10. Use of mineral physics, with geodynamic modelling and seismology, to investigate flow in the Earth's mantle

    International Nuclear Information System (INIS)

    Blackman, D K

    2007-01-01

    Seismologists and mineral physicists have known for decades that anisotropy inherent in mantle minerals could provide a means to relate surface seismic measurements to deformation patterns at great depth in the Earth, where direct geologic observations would never be possible. Prior to the past decade, only qualitative relationships or simple symmetry assumptions between mantle flow (deformation), mineral alignment and seismic anisotropy were possible. Recent numerical methods now allow quantitative incorporation of constraints from mineral physics to flow/deformation models and, thereby, direct estimates of the resulting pattern of seismic anisotropy can be made and compared with observed signatures. Numerical methods for simulating microstructural deformation within an aggregate of minerals subjected to an arbitrary stress field make it possible to quantitatively link crystal-scale processes with large-scale Earth processes of mantle flow and seismic wave propagation, on regional (100s of kilometres) and even global scales. Such linked numerical investigations provide a rich field for exploring inter-dependences of micro and macro processes, as well as a means to determine the extents to which viable seismic experiments could discern between different models of Earth structure and dynamics. The aim of this review is to provide an overview of why and how linked numerical models are useful for exploring processes in the mantle and how they relate to surface tectonics. A brief introduction to the basic concepts of deformation of mantle minerals and the limits of knowledge currently available are designed to serve both the subsequent discussions in this review and as an entry point to more detailed literature for readers interested in pursuing the topic further. The reference list includes both primary sources and pertinent review articles on individual aspects of the combined subjects covered in the review. A series of flow/texturing models illustrate the differences that can arise when different methods or different flow parameters are employed. Representative seismic results illustrate the types of studies done to date and the inferences possible using their anisotropy measurements. Trade-offs involved in the modelling assumptions and seismic data processing methods are touched on. A final example illustrates the effects, relative to a 2D model of mantle flow near a subduction zone, that flow in a third dimension can have on anisotropy patterns

  11. Seismology of adolescent neutron stars: Accounting for thermal effects and crust elasticity

    Science.gov (United States)

    Krüger, C. J.; Ho, W. C. G.; Andersson, N.

    2015-09-01

    We study the oscillations of relativistic stars, incorporating key physics associated with internal composition, thermal gradients and crust elasticity. Our aim is to develop a formalism which is able to account for the state-of-the-art understanding of the complex physics associated with these systems. As a first step, we build models using a modern equation of state including composition gradients and density discontinuities associated with internal phase transitions (like the crust-core transition and the point where muons first appear in the core). In order to understand the nature of the oscillation spectrum, we carry out cooling simulations to provide realistic snapshots of the temperature distribution in the interior as the star evolves through adolescence. The associated thermal pressure is incorporated in the perturbation analysis, and we discuss the presence of g -modes arising as a result of thermal effects. We also consider interface modes due to phase-transitions and the gradual formation of the star's crust and the emergence of a set of shear modes.

  12. Examination of the geology and seismology associated with area 410 at the Nevada test site

    International Nuclear Information System (INIS)

    Hannon, W.J.; McKague, H.L.

    1975-01-01

    This report summarizes regional and local geology at the Nevada Test Site and identifies major tectonic features and active faults. Sufficient information is given to perform seismic safety analyses of present and future critical construction at the Super Kukla Site and Sites A and B in Area 410. However, examination of local minor faults and joints and soil thickness studies should be undertaken at construction time. The Cane Spring Fault is identified as the most significant geologic feature from the viewpoint of the potential seismic risk. Predictions of the peak ground acceleration (0.9 g), the response spectra for the Safe Shutdown Earthquake, and the maximum displacement across the Cane Spring Fault are made. (U.S.)

  13. Laboratory simulations of fluid/gas induced micro-earthquakes: application to volcano seismology.

    Directory of Open Access Journals (Sweden)

    Philip Michael Benson

    2014-11-01

    Full Text Available Understanding different seismic signals recorded in active volcanic regions allows geoscientists to derive insight into the processes that generate them. A key type is known as Low Frequency or Long Period (LP event, generally understood to be generated by different fluid types resonating in cracks and faults. The physical mechanisms of these signals have been linked to either resonance/turbulence within fluids, or as a result of fluids ‘sloshing’ due to a mixture of gas and fluid being present in the system. Less well understood, however, is the effect of the fluid type (phase on the measured signal. To explore this, we designed an experiment in which we generated a precisely controlled liquid to gas transition in a closed system by inducing rapid decompression of fluid-filled fault zones in a sample of basalt from Mt. Etna Volcano, Italy. We find that fluid phase transition is accompanied by a marked frequency shift in the accompanying microseismic dataset that can be compared to volcano seismic data. Moreover, our induced seismic activity occurs at pressure conditions equivalent to hydrostatic depths of 200 to 750 meters. This is consistent with recently measured dominant frequencies of LP events and with numerous models.

  14. Mapping of impediments to contamination flow using multicomponent reflection seismology at the Savannah River Site

    International Nuclear Information System (INIS)

    Dickenson, O.A.; Steensma, G.J.; Boyd, T.M.

    1996-01-01

    A major obstacle to the remediation of contaminated aquifers at the Savannah River Site in Aiken, South Carolina is the presence of discontinuous sand and clay lenses that are difficult to map effectively using geologic and geophysical well logs. In order to map these discontinuous sand and clay lenses we acquire two perpendicular nine-component (9C) seismic lines, a 9C Vertical Seismic Profile, (VSP) and p-wave and s-wave sonic logs in a borehole south of the Old Burial Ground at the Savannah River Site within which were available natural gamma ray and interpreted geology logs. P-wave reflections are interpreted as originating from water table, the Tan Clay, the Green Clay, the top of the Ellenton Clay, and a calcareous sediment layer within the Barnwell/McBean aquifer. Along the east-west trending line, reflectors are generally continuous except for the occurrence of a discontinuity in the upper reflectors near the east end of the line. This discontinuity could be interpreted as a sediment slump feature possibly related to the dissolution of the calcareous sediment layer, or as the eastern terminus of a large scour feature. Along the north-south trending line, reflectors are spatially less continuous and are interpreted as being cut by several channel/scour features

  15. Imaging of Scattered Wavefields in Passive and Controlled-source Seismology

    KAUST Repository

    AlTheyab, Abdullah

    2015-01-01

    complex and our demands for higher resolution increase. This dissertation introduces two new methods that use scattered waves for improving the resolution of subsurface images: natural migration of passive seismic data and convergent full

  16. Obtaining Unique, Comprehensive Deep Seismic Sounding Data Sets for CTBT Monitoring and Broad Seismological Studies

    National Research Council Canada - National Science Library

    Morozov, Igor B; Morozova, Elena A; Smithson, Scott B

    2007-01-01

    .... The data include 3-component records from 22 Peaceful Nuclear Explosions (PNEs) and over 500 chemical explosions recorded by a grid of linear, reversed seismic profiles covering a large part of Northern Eurasia...

  17. Towards Porting a Real-World Seismological Application to the Intel MIC Architecture

    OpenAIRE

    V. Weinberg

    2014-01-01

    This whitepaper aims to discuss first experiences with porting an MPI-based real-world geophysical application to the new Intel Many Integrated Core (MIC) architecture. The selected code SeisSol is an application written in Fortran that can be used to simulate earthquake rupture and radiating seismic wave propagation in complex 3-D heterogeneous materials. The PRACE prototype cluster EURORA at CINECA, Italy, was accessed to analyse the MPI-performance of SeisSol on Intel Xeon Phi on both sing...

  18. A Seismological Portrait of the Anomalous 1996 Bardarbunga Volcano, Iceland, Earthquake (Invited)

    Science.gov (United States)

    Tkalcic, H.; Dreger, D. S.; Foulger, G. R.; Julian, B. R.; Fichtner, A.

    2009-12-01

    The Bardarbunga volcano lies beneath the 500-m-thick Vatnajokull icecap, the largest glacier in Europe. Earthquakes with atypical seismic radiation have occurred beneath the Bardarbunga caldera and have been routinely reported in the Global CMT catalog. An earthquake with Mw 5.6 and a strong non-double-couple (NDC) radiation pattern occurred beneath the caldera on 29 September, 1996. A peculiarity of that earthquake was that it was the first in a sequence of seismic and magmatic events and that it was followed, not preceded or accompanied, by a major eruption which ultimately led to a breakout flood from the subglacial caldera lake. The earthquake was recorded well by the regional-scale Iceland Hotspot Project seismic experiment. One of the proposed hypotheses to explain the observed displacements and the sequence of events was the inflation of a shallow magma chamber that might have caused rupture on ring faults below the chamber. Iceland has a heterogeneous crust, with variable thickness, and thus a 1D structural model is not ideal for waveform modeling. We investigated the earthquake with a point-source complete moment-tensor (MT) inversion method using regional long-period seismic waveforms and a composite structural model of Iceland based on joint modeling of teleseismic receiver functions and surface-wave dispersion. When such a model is used, the waveform modeling yields a NDC solution with a strong, vertically oriented compensated linear vector dipole component and a statistically insignificant volumetric contraction. The absence of a volumetric component is surprising in the case of a large volcanic earthquake that cannot be explained by shear slip on a planar fault. A possible mechanism that can produce an earthquake without a volumetric component involves two offset sources with similar but opposite volume changes. We show that although such a model cannot be ruled out, it is unlikely. In order to investigate the hypothesis of a rupture occurring on a ring fault, we simulated different caldera geometries and rupture scenarios on the walls of a conical surface. We obtained excellent fits for ruptures extending along one-half perimeter of the caldera at a super-shear velocity, but could not determine the location of the initiation point nor the rupture propagation direction. If studied in different frequency bands however, the point source MT inversion fails to simultaneously explain the observed data, which indicates the presence of finite-source effects. Using a 3D model of the Icelandic crust and upper mantle, we perform a probabilistic finite source inversion. One of the most robust outcomes of this is a well constrained source duration with approximately equal amount of energy radiated by individual segments. This indicates that the caldera dropped coherently as a single block. We speculate that the earthquake accompanied a small-scale eruption that went unnoticed prior to the caldera drop. The caldera drop could have increased the pressure in the magma chamber thus inducing the principal eruption.

  19. Review of past research areas – seismology and mine layout design.

    CSIR Research Space (South Africa)

    Handley, MF

    2002-02-01

    Full Text Available determined from chaos theory. The first output is the Integrated Seismic System, which had already been developed and implemented before it received SIMRAC support. However, it did undergo significant improvement during the course of the research support... 3. These include a clear understanding of chaos in seismically active rock masses, accurate measurements of seismic instability indicators, and reliable real-time monitoring. The work is at the forefront of modern chaos theory, pattern...

  20. The 12th June 2017 Mw = 6.3 Lesvos earthquake from detailed seismological observations

    Science.gov (United States)

    Papadimitriou, P.; Kassaras, I.; Kaviris, G.; Tselentis, G.-A.; Voulgaris, N.; Lekkas, E.; Chouliaras, G.; Evangelidis, C.; Pavlou, K.; Kapetanidis, V.; Karakonstantis, A.; Kazantzidou-Firtinidou, D.; Fountoulakis, I.; Millas, C.; Spingos, I.; Aspiotis, T.; Moumoulidou, A.; Skourtsos, E.; Antoniou, V.; Andreadakis, E.; Mavroulis, S.; Kleanthi, M.

    2018-04-01

    A major earthquake (Mwö=ö6.3) occurred on the 12th of June 2017 (12:28 GMT) offshore, south of the SE coast of Lesvos Island, at a depth of 13ökm, in an area characterized by normal faulting with an important strike-slip component in certain cases. Over 900 events of the sequence between 12 and 30 June 2017 were manually analyzed and located, employing an optimized local velocity model. Double-difference relocation revealed seven spatially separated groups of events, forming two linear branches, roughly aligned N130°E, compatible with the strike of known mapped faults along the southern coast of Lesvos Island. Spatiotemporal analysis indicated gradual migration of seismicity towards NW and SE from the margins of the main rupture, while a strong secondary sequence at a separate fault patch SE of the mainshock, oriented NW-SE, was triggered by the largest aftershock (Mwö=ö5.2) that occurred on 17 June. The focal mechanisms of the mainshock (φö=ö122°, δö=ö40° and λö=ö-83°) and of the major aftershocks were determined using regional moment tensor inversion. In most cases normal faulting was revealed with the fault plane oriented in a NW-SE direction, dipping SW, with the exception of the largest aftershock that was characterized by strike-slip faulting. Stress inversion revealed a complex stress field south of Lesvos, related both to normal, in an approximate E-W direction, and strike-slip faulting. All aftershocks outside the main rupture, where gradual seismicity migration was observed, are located within the positive lobes of static stress transfer determined by applying the Coulomb criterion for the mainshock. Stress loading on optimal faults under a strike-slip regime explains the occurrence of the largest aftershock and the seismicity that was triggered at the eastern patch of the rupture zone.

  1. Using the Seismology of Non-magnetic Chemically Peculiar Stars as ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... Chemical composition is a good tracer of the hydrodynamical processes that occur in stars as they often lead to mixing and particle transport. By comparing abundances predicted by models and those observed in stars we can infer some constraints on those mixing processes. As pulsations in the stars are ...

  2. Seismological Experiment in Stonava Area: Evaluation of Validity of Measured Data

    Czech Academy of Sciences Publication Activity Database

    Kaláb, Zdeněk; Knejzlík, Jaromír; Lednická, Markéta

    2009-01-01

    Roč. 4, 2a (2009), s. 95-103 ISSN 1896-3145. [Ochrona środowiska w górnictwie podziemnym, odkrywkowym i otworowym. Bochnia, 20.05.2009-22.05.2009] R&D Projects: GA ČR GA105/07/0878 Institutional research plan: CEZ:AV0Z30860518 Keywords : mining induced seismicity * experimental measurement * seismic loading Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  3. Seismology on drifting icebergs: Catching earthquakes, tsunamis, swell, and iceberg music

    Science.gov (United States)

    Okal, E. A.; Macayeal, D. R.

    2006-12-01

    For the past 3 years, we have operated seismometers on large icebergs either parked or drifting in the Ross Sea, with an additional station at Nascent, where the next section of the Ross Ice Shelf is expected to calf. Apart from their primary goal of studying in situ tremor generated inside the ice, presumed to arise during collisions and fragmentation, our stations have functioned as teleseismic observatories, despite a noisy environment in the 20-100 mHz frequency band, corresponding to the free bobbing and rolling of the icebergs. As expected, both P and Rayleigh waves from distant earthquakes are recorded on the vertical channels as unperturbed ground motion, with acceptable values of energy flux (P) or magnitude (Rayleigh); however, due to noise level at mantle periods, only Rayleigh waves from the largest events (Sumatra 2004; Nias 2005) could be quantified meaningfully. T waves from distant earthquakes along the EPR can be recorded, but the acoustic-to-seismic transition at the ice boundary is less effcient than at typical island stations. The 2004 Sumatra tsunami was recorded on all 3 components at the 3 stations; the inferred amplitudes (about 15 cm vertical and 1.3 m horizontal, peak-to-peak) are in general agreement with global simulations, and suggest that the bergs rode the tsunami without intrinsic deformation; a small tsunami is also detected for the Macquarie earthquake of 23 Dec. 2004. Our stations regularly recorded long wavetrains in the 40-60 mHz range, dispersed under the deep-water approximation, and corresponding to sea swell propagating across the entire ocean from major storms in the Northern and Equatorial Pacific. In the case of a major depression in the Gulf of Alaska in Late October 2005, recorded on the ice 6 days later, Iceberg B-15A underwent at the same time a severe fragmentation, leading to legitimate speculation on the role of storm waves in triggering its break-up. Finally, our stations recorded a large number of local signals originating in the ice masses, many of which characterized by clearly preferential eigenfrequencies in the 1-3 Hz range, accomnpanied by harmonics, and discussed in detail in a companion presentation (MacAyeal et al.).

  4. Engineering seismology application of a computer base comprise of french macroseismic data

    International Nuclear Information System (INIS)

    Godefroy, P.; Levret, A.

    1990-01-01

    France, a moderately seismic country, has compiled a computer base of macroseismic data for the purpose of satisfying safety requirements implicated in its nuclear electric program. This evolving base includes not only information about the event and its epicenter, but also all the individual macroseismic observations. The analysis of these data serves as an input to the deterministic assessment of seismic hazard for high-risk facilities. Current practice implements a seismotectonic approach wherein geological and seismic data are used to determine active faults or, when this is not possible, provinces shown to be homogeneous on the basis of a certain number of criteria. According to the safety procedure applied, the first step is to act as if this earthquake could occur at any spot within the entity to which it belongs, and thence at the point nearest the site. The maximum macroseismic intensity induced thereby on the site, either after displacing isoseismals or through use of laws of intensity attenuation versus distance, constitutes an initial level of seismic hazard with respect to which protective measures in the design of certain types of installation are taken. In the nuclear field, the regulations call for a second level of hazard, intended to afford an additional safety margin expected to cover, notably, uncertainties in the seismotectonic analysis or insufficiencies in the seismic data itself. This second level of hazard, designated Safety Design Earthquake, the effect of which is to raise the first-level intensity by one degree, is characterized by its response spectrum, in terms of which the facility's safety functions must remain unimpaired. Examples, drawn from south-eastern France, of the procedure just described will be presented

  5. TECTONIC AND SEISMOLOGICAL ASPECTS OF THE GREAT JAPAN EARTHQUAKE OF MARCH 11, 2011

    Directory of Open Access Journals (Sweden)

    Ivan N. Tikhonov

    2011-01-01

    Full Text Available The publication presents a review of the structure and seismotectonic features of the Pacific margin of the NorthEastern Honshu Island on the basis of data from seismic reflection and CDP, drilling and detailed seismic studies in view of the megaearthquake (Mw=9.0 which occurred in Japan on March 11, 2011. The megaearthquake is discussed in terms of its position in the succession of the strongest events (M≥7.6 in the area under study within the historical period and in the recent timeline. It is suggested that the period of recurrence is about 40 years for great events and about 1000+ years for megaearthquakes. A number of facts suggesting a probability of a planetaryscale earthquake in the Honshu Island region are revealed. Specifically, a seismic gap with a total length of about 800 km is determined in the study area. It is located southward of 39° north latitude has already manifested aftershocks of the megaearthquake of March 11, 2011. It is probable that the megaearthquake was related to the deep thrust along the Benioff zone and the Oyashio nappe being its structural cap rock in the middle Pacific slope. The sequence of its aftershocks is compared with those of the SumatraAndaman (Mw=9.3, 2004 and Simushir (Mw=8.3, 2006 earthquakes. It is established that development of the aftershock sequences of the first and second events was very similar in time, and development of the areas of aftershock epicentres of the first and third earthquakes is similar in space. The above similarities give grounds to suggest that an aftershock (M~8.0 is possible with a relative shifting from the main shock towards the deep trench.

  6. Preliminary results from receiver function analysis in a seismological network across the Pamir

    Science.gov (United States)

    Schneider, Felix M.; Yuan, Xiaohui; Sippl, Christan; Schurr, Bernd; Mechie, James; Minaev, Vlad; Oimahmadov, Ilhomjon; Gadoev, Mustafo; Abdybachaev, Ulan A.

    2010-05-01

    The multi-disciplinary TIen Shan-PAmir GEodynamic (TIPAGE) program aims to investigate the dynamics of the orogeny of the Tien Shan and Pamir mountains, which are situated in south Kyrgyzstan and east Tajikistan in Central Asia. Deformation and uplift accompanied by crustal thickening is mainly induced by the collision between the Indian and Eurasian continental plates. As a local feature this collision provides the world's largest active intra-continental subduction zone. Within the framework of the TIPAGE program we operate a temporary seismic array consisting of 32 broadband and 8 short period seismic stations for a period of two years (from 2008 to 2010) covering an area of 300 x 300 km over the main part of the central Pamir plateau and the Alai-range of the southern Tien Shan. In the first year 24 broadband stations were set up in a 350-km long north-south profile geometry from Osh in southern Kyrgyzstan to Zorkul in south-eastern Tajikistan with approximately 15 km station spacing. We perform a receiver function (RF) analysis of converted P and S waves from teleseismic earthquakes at epicentral distances of 35-95 degrees with a minimum magnitude of 5.5. Therefore we decompose their wavefields by rotating the coordinate systems of the recorded seismograms from a N,E,Z into a SH,SV,P system. RFs are isolated by deconvolution of the P-component from the SH- and SV-component. They provide a robust tool to locate discontinuities in wave velocity like the Moho and thus represent the method of choice to determine crustal thickness. First results show a crustal thickness of 70-80km. Xenolith findings from depths of 100km reported by Hacker et al. (2005) give indication for even higher values. The N-S profile geometry will produce a high resolution RF image to map the gross crustal and lithospheric structure. In addition a 2D network with additional 16 stations will enable an investigation of lateral structure variation. We give an introduction to the project and methodology as well as a presentation of our preliminary most recent results on crustal thickness and Poisson's ratio along the profile from the data of the first year.

  7. Keeping the History in Historical Seismology: The 1872 Owens Valley, California Earthquake

    International Nuclear Information System (INIS)

    Hough, Susan E.

    2008-01-01

    The importance of historical earthquakes is being increasingly recognized. Careful investigations of key pre-instrumental earthquakes can provide critical information and insights for not only seismic hazard assessment but also for earthquake science. In recent years, with the explosive growth in computational sophistication in Earth sciences, researchers have developed increasingly sophisticated methods to analyze macroseismic data quantitatively. These methodological developments can be extremely useful to exploit fully the temporally and spatially rich information source that seismic intensities often represent. For example, the exhaustive and painstaking investigations done by Ambraseys and his colleagues of early Himalayan earthquakes provides information that can be used to map out site response in the Ganges basin. In any investigation of macroseismic data, however, one must stay mindful that intensity values are not data but rather interpretations. The results of any subsequent analysis, regardless of the degree of sophistication of the methodology, will be only as reliable as the interpretations of available accounts - and only as complete as the research done to ferret out, and in many cases translate, these accounts. When intensities are assigned without an appreciation of historical setting and context, seemingly careful subsequent analysis can yield grossly inaccurate results. As a case study, I report here on the results of a recent investigation of the 1872 Owen's Valley, California earthquake. Careful consideration of macroseismic observations reveals that this event was probably larger than the great San Francisco earthquake of 1906, and possibly the largest historical earthquake in California. The results suggest that some large earthquakes in California will generate significantly larger ground motions than San Andreas fault events of comparable magnitude

  8. Benefits derived by South Africa from the Council for Geoscience's Seismology Programme

    International Nuclear Information System (INIS)

    Kleywegt, R.

    1999-01-01

    This presentation deals with the situation of a country in the small, developing league and is applicable to a large number of member states. It traces the progress made in South Africa at the Council for Geoscience (mainly its predecessor the Geological Survey of South Africa) since the late 1950s. First World countries have a capacity many times more than that of South Africa in terms of economic, scientific, technological and sociological capacity and for them the developments would occur normally in a number, even large number of institutions. In their case a reasonable comparison might be with a province, state or region. Only one of the verification technologies will be discussed

  9. Postseismic relaxation along the San Andreas fault at Parkfield from continuous seismological observations.

    Science.gov (United States)

    Brenguier, F; Campillo, M; Hadziioannou, C; Shapiro, N M; Nadeau, R M; Larose, E

    2008-09-12

    Seismic velocity changes and nonvolcanic tremor activity in the Parkfield area in California reveal that large earthquakes induce long-term perturbations of crustal properties in the San Andreas fault zone. The 2003 San Simeon and 2004 Parkfield earthquakes both reduced seismic velocities that were measured from correlations of the ambient seismic noise and induced an increased nonvolcanic tremor activity along the San Andreas fault. After the Parkfield earthquake, velocity reduction and nonvolcanic tremor activity remained elevated for more than 3 years and decayed over time, similarly to afterslip derived from GPS (Global Positioning System) measurements. These observations suggest that the seismic velocity changes are related to co-seismic damage in the shallow layers and to deep co-seismic stress change and postseismic stress relaxation within the San Andreas fault zone.

  10. The 2016 Mihoub (north-central Algeria) earthquake sequence: Seismological and tectonic aspects

    Science.gov (United States)

    Khelif, M. F.; Yelles-Chaouche, A.; Benaissa, Z.; Semmane, F.; Beldjoudi, H.; Haned, A.; Issaadi, A.; Chami, A.; Chimouni, R.; Harbi, A.; Maouche, S.; Dabbouz, G.; Aidi, C.; Kherroubi, A.

    2018-06-01

    On 28 May 2016 at 23:54 (UTC), an Mw5.4 earthquake occurred in Mihoub village, Algeria, 60 km southeast of Algiers. This earthquake was the largest event in a sequence recorded from 10 April to 15 July 2016. In addition to the permanent national network, a temporary network was installed in the epicentral region after this shock. Recorded event locations allow us to give a general overview of the sequence and reveal the existence of two main fault segments. The first segment, on which the first event in the sequence was located, is near-vertical and trends E-W. The second fault plane, on which the largest event of the sequence was located, dips to the southeast and strikes NE-SW. A total of 46 well-constrained focal mechanisms were calculated. The events located on the E-W-striking fault segment show mainly right-lateral strike-slip (strike N70°E, dip 77° to the SSE, rake 150°). The events located on the NE-SW-striking segment show mainly reverse faulting (strike N60°E, dip 70° to the SE, rake 130°). We calculated the static stress change caused by the first event (Md4.9) of the sequence; the result shows that the fault plane of the largest event in the sequence (Mw5.4) and most of the aftershocks occurred within an area of increased Coulomb stress. Moreover, using the focal mechanisms calculated in this work, we estimated the orientations of the main axes of the local stress tensor ellipsoid. The results confirm previous findings that the general stress field in this area shows orientations aligned NNW-SSE to NW-SE. The 2016 Mihoub earthquake sequence study thus improves our understanding of seismic hazard in north-central Algeria.

  11. Using the Seismology of Non-magnetic Chemically Peculiar Stars as ...

    Indian Academy of Sciences (India)

    stars we can infer some constraints on those mixing processes. As pulsa- tions in the ... Finally, microscopic diffusion due to gravity and radiation pressure ... complications posed by the largely unknown strength and geometry of the magnetic.

  12. Comparison of four moderate-size earthquakes in southern California using seismology and InSAR

    Science.gov (United States)

    Mellors, R.J.; Magistrale, H.; Earle, P.; Cogbill, A.H.

    2004-01-01

    Source parameters determined from interferometric synthetic aperture radar (InSAR) measurements and from seismic data are compared from four moderate-size (less than M 6) earthquakes in southern California. The goal is to verify approximate detection capabilities of InSAR, assess differences in the results, and test how the two results can be reconciled. First, we calculated the expected surface deformation from all earthquakes greater than magnitude 4 in areas with available InSAR data (347 events). A search for deformation from the events in the interferograms yielded four possible events with magnitudes less than 6. The search for deformation was based on a visual inspection as well as cross-correlation in two dimensions between the measured signal and the expected signal. A grid-search algorithm was then used to estimate focal mechanism and depth from the InSAR data. The results were compared with locations and focal mechanisms from published catalogs. An independent relocation using seismic data was also performed. The seismic locations fell within the area of the expected rupture zone for the three events that show clear surface deformation. Therefore, the technique shows the capability to resolve locations with high accuracy and is applicable worldwide. The depths determined by InSAR agree with well-constrained seismic locations determined in a 3D velocity model. Depth control for well-imaged shallow events using InSAR data is good, and better than the seismic constraints in some cases. A major difficulty for InSAR analysis is the poor temporal coverage of InSAR data, which may make it impossible to distinguish deformation due to different earthquakes at the same location.

  13. CATS, continuous automated testing of seismological, hydroacoustic, and infrasound (SHI) processing software.

    Science.gov (United States)

    Brouwer, Albert; Brown, David; Tomuta, Elena

    2017-04-01

    To detect nuclear explosions, waveform data from over 240 SHI stations world-wide flows into the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), located in Vienna, Austria. A complex pipeline of software applications processes this data in numerous ways to form event hypotheses. The software codebase comprises over 2 million lines of code, reflects decades of development, and is subject to frequent enhancement and revision. Since processing must run continuously and reliably, software changes are subjected to thorough testing before being put into production. To overcome the limitations and cost of manual testing, the Continuous Automated Testing System (CATS) has been created. CATS provides an isolated replica of the IDC processing environment, and is able to build and test different versions of the pipeline software directly from code repositories that are placed under strict configuration control. Test jobs are scheduled automatically when code repository commits are made. Regressions are reported. We present the CATS design choices and test methods. Particular attention is paid to how the system accommodates the individual testing of strongly interacting software components that lack test instrumentation.

  14. Investigations of the seismological input to the safety design of nuclear power reactors in New England

    International Nuclear Information System (INIS)

    Chinnery, M.A.

    1978-08-01

    A detailed study of available scientific literature concerning the estimation of maximum possible earthquakes shows that all available methods are empirical and lack a sound physical basis. Evidence that even the empirical methods are valid is verid weak, primarily because of the short length of the earthquake record in most areas. Attempt to use global earthquake catalogs to examine the regional variation of maximum possible earthquakes is unsuccessful. It is demonstrated that saturation of the magnituge scale and biases introduced by instrumental clipping combine to make m/sub b/ values for large erthquakes very unreliable, and to obscure the precence or absence of maximum possible earthquakes. A progress report on a study of New England crust and upper mantle structure is included

  15. Imaging of Scattered Wavefields in Passive and Controlled-source Seismology

    KAUST Repository

    AlTheyab, Abdullah

    2015-12-01

    Seismic waves are used to study the Earth, exploit its hydrocarbon resources, and understand its hazards. Extracting information from seismic waves about the Earth’s subsurface, however, is becoming more challenging as our questions become more complex and our demands for higher resolution increase. This dissertation introduces two new methods that use scattered waves for improving the resolution of subsurface images: natural migration of passive seismic data and convergent full-waveform inversion. In the first part of this dissertation, I describe a method where the recorded seismic data are used to image subsurface heterogeneities like fault planes. This method, denoted as natural migration of backscattered surface waves, provides higher resolution images for near-surface faults that is complementary to surface-wave tomography images. Our proposed method differ from contemporary methods in that it does not (1) require a velocity model of the earth, (2) assumes weak scattering, or (3) have a high computational cost. This method is applied to ambient noise recorded by the US-Array to map regional faults across the American continent. Natural migration can be formulated as a least-squares inversion to furtherer enhance the resolution and the quality of the fault images. This inversion is applied to ambient noise recorded in Long Beach, California to reveal a matrix of shallow subsurface faults. The second part of this dissertation describes a convergent full waveform inversion method for controlled source data. A controlled source excites waves that scatter from subsurface reflectors. The scattered waves are recorded by a large array of geophones. These recorded waves can be inverted for a high-resolution image of the subsurface by FWI, which is typically convergent for transmitted arrivals but often does not converge for deep reflected events. I propose a preconditioning approach that extends the ability of FWI to image deep parts of the velocity model, which significantly improves the chances for finding hydrocarbon deposits.

  16. Seismology-based early identification of dam-formation landquake events.

    Science.gov (United States)

    Chao, Wei-An; Zhao, Li; Chen, Su-Chin; Wu, Yih-Min; Chen, Chi-Hsuan; Huang, Hsin-Hua

    2016-01-12

    Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥20 s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1-3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents.

  17. Seismological evidence of fault weakening due to erosion by fluids from observations of intraplate earthquake swarms

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav; Hrubcová, Pavla

    2017-01-01

    Roč. 122, č. 5 (2017), s. 3701-3718 ISSN 2169-9313 R&D Projects: GA MŠk(CZ) LM2015079; GA ČR GC16-19751J; GA ČR GA17-19297S Institutional support: RVO:67985530 Keywords : earthquke swarm * seismic cycle * moment tensor * fault weakening * fluids Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 3.350, year: 2016

  18. Seismological Imaging of Melt Production Regions Beneath the Backarc Spreading Center and Volcanic Arc, Mariana Islands

    Science.gov (United States)

    Wiens, Douglas; Pozgay, Sara; Barklage, Mitchell; Pyle, Moira; Shiobara, Hajime; Sugioka, Hiroko

    2010-05-01

    We image the seismic velocity and attenuation structure of the mantle melt production regions associated with the Mariana Backarc Spreading Center and Mariana Volcanic Arc using data from the Mariana Subduction Factory Imaging Experiment. The passive component of this experiment consisted of 20 broadband seismographs deployed on the island chain and 58 ocean-bottom seismographs from June, 2003 until April, 2004. We obtained the 3D P and S wave velocity structure of the Mariana mantle wedge from a tomographic inversion of body wave arrivals from local earthquakes as well as P and S arrival times from large teleseismic earthquakes determined by multi-channel cross correlation. We also determine the 2-D attenuation structure of the mantle wedge using attenuation tomography based on local and regional earthquake spectra, and a broader-scale, lower resolution 3-D shear velocity structure from inversion of Rayleigh wave phase velocities using a two plane wave array analysis approach. We observe low velocity, high attenuation anomalies in the upper mantle beneath both the arc and backarc spreading center. These anomalies are separated by a higher velocity, lower attenuation region at shallow depths (< 80 km), implying distinct magma production regions for the arc and backarc in the uppermost mantle. The largest magnitude anomaly beneath the backarc spreading center is found at shallower depth (25-50 km) compared to the arc (50-100 km), consistent with melting depths estimated from the geochemistry of arc and backarc basalts (K. Kelley, pers. communication). The velocity and attenuation signature of the backarc spreading center is narrower than the corresponding anomaly found beneath the East Pacific Rise by the MELT experiment, perhaps implying a component of focused upwelling beneath the spreading center. The strong velocity and attenuation anomaly beneath the spreading center contrasts strongly with preliminary MT inversion results showing no conductivity anomaly in the same region (Matsuno and Seama, pers. communication). This suggests that the seismic anomalies may result from very small in-situ melt fractions that are not electrically connected with the surface. The larger-scale surface wave inversion shows three regions of slow upper mantle velocities coincident with gravity lows along the spreading center and separated by about 200 km along strike; these anomalies may correspond to regions of strong upwelling in the arc-backarc system.

  19. SEISMOLOGICAL OBSERVATORY AT QUINDIO UNIVERSITY (O.S.Q.: A FIRM LONG-TERM STEP TOWARD RESOLVING REGIONAL SEISMICITY

    Directory of Open Access Journals (Sweden)

    Monsalve Jaramillo Hugo

    2005-08-01

    Full Text Available El Eje Cafetero (zona central de Colombia, cultivada con café, y en particular, el departamento del Quindío es constantemente golpeada por sismos de diferentes magnitudes. Los sismos son el resultado de la compleja tectónica regional debido a la interacción entre las placa Nazca, Caribe y Sur América. La convergencia de estas placas es responsable de la formación de los Andes. Por estas razones, el OSQ (Observatorio Sismológico del Quindío e INGEOMINAS, como las entidades estatales encargadas de monitorear la actividad sísmica, han de contribuir, a si como los centros regionales de investigación, al desarrollo de los estudios sismológicos y el análisis de la actividad tectónica local, para así obtener nuevos conocimientos a cerca de los desastres naturales que amenazan a las comunidades en la región y entender mejor la estructura interna de la corteza en la región del Eje Cafetero.La combinación de diferentes modelos de velocidad para la región del Eje Cafetero ha permitido la definición de elementos clave para tener una mejor percepción de la estructura de la corteza. En consecuencia, la determinación de un modelo de velocidades mejorado para la región cafetera ha ayudado a localizar mejor los sismos y a determinar con mayor precisión los espesores de la corteza y la estructura del manto superior entre los terrenos adyacentes que fueron generados en diferentes períodos geológicos.La magnitud ML fue determinada para los campos cercanos e intermedios y usando el modelo presentado en este articulo, el problema del rango dinámico de saturación de los sismógrafos durante sismos relevantes en campo cercano es solucionado. La magnitud local de algunos sismos superficiales fue calculada usando sismos con distancias epicentrales entre 10Km y 300Km asi como las magnitudes de algunos sismos profundos con distancias hipocentrales entre 100 Km y 600 Km.La evaluación del potencial sísmico en la región del Eje Cafetero empieza con el registro de la sismicidad reciente en Chocó y en la parte norte del departamento del Valle, y está basada en el análisis comparativo entre esta sismicidad y la registrada antes de la ocurrencia de los sismos mas importantes de los últimos 42 años. Finalmente, considerando las dos fuentes de subducción, un sismo cuya magnitud de momento sísmico entre 6.7 y 7.3 podría esperarse en la próxima década, con una probabilidad de 87%.

  20. Analyses of computer programs for the probabilistic estimation of design earthquake and seismological characteristics of the Korean Peninsula

    International Nuclear Information System (INIS)

    Lee, Gi Hwa

    1997-11-01

    The purpose of the present study is to develop predictive equations from simulated motions which are adequate for the Korean Peninsula and analyze and utilize the computer programs for the probabilistic estimation of design earthquakes. In part I of the report, computer programs for the probabilistic estimation of design earthquake are analyzed and applied to the seismic hazard characterizations in the Korean Peninsula. In part II of the report, available instrumental earthquake records are analyzed to estimate earthquake source characteristics and medium properties, which are incorporated into simulation process. And earthquake records are simulated by using the estimated parameters. Finally, predictive equations constructed from the simulation are given in terms of magnitude and hypocentral distances

  1. Deep Explosive Volcanism on the Gakkel Ridge and Seismological Constraints on Shallow Recharge at TAG Active Mound

    Science.gov (United States)

    2013-02-01

    dccoupled from tlle erupting Java . We assess the feasibility of such a model by examining the time- scales of melting and magnitude of melt accumula- tion...bands reflect sequential precipitation within cavities and repeated opening of fractures. Some anhydrite veins contain angular clasts of competent, low...158-957C-11N-2) (Figure 16 of Humphris et al., [1996]). Angular clasts of fine-grained, massive pyrite occur along the edges of the anhydrite

  2. The USGS "Did You Feel It?" Macroseismic Intensity Maps: Lessons Learned from a Decade of Citizen-Empowered Seismology

    Science.gov (United States)

    Wald, D. J.; Worden, C. B.; Quitoriano, V. R.; Dewey, J. W.

    2012-12-01

    The U.S. Geological Survey (USGS) "Did You Feel It?" (DYFI) system is an automated approach for rapidly collecting macroseismic intensity (MI) data from Internet users' shaking and damage reports and generating intensity maps immediately following earthquakes; it has been operating for over a decade (1999-2012). The internet-based interface allows for a two-way path of communication between seismic data providers (scientists) and earthquake information recipients (citizens) by swapping roles: users looking for information from the USGS become data providers to the USGS. This role-reversal presents opportunities for data collection, generation of good will, and further communication and education. In addition, online MI collecting systems like DYFI have greatly expanded the range of quantitative analyses possible with MI data and taken the field of MI in important new directions. The maps are made more quickly, usually provide more complete coverage at higher resolution, and allow data collection at rates and quantities never before considered. Scrutiny of the USGS DYFI data indicates that one-decimal precision is warranted, and web-based geocoding services now permit precise locations. The high-quality, high-resolution, densely sampled MI assignments allow for peak ground motion (PGM) versus MI analyses well beyond earlier studies. For instance, Worden et al. (2011) used large volumes of data to confirm low standard deviations for multiple, proximal DYFI reports near a site, and they used the DYFI observations with PGM data to develop bidirectional, ground motion-intensity conversion equations. Likewise, Atkinson and Wald (2007) and Allen et al. (2012) utilized DYFI data to derive intensity prediction equations directly without intermediate conversion of ground-motion prediction equation metrics to intensity. Both types of relations are important for robust historic and real-time ShakeMaps, among other uses. In turn, ShakeMap and DYFI afford ample opportunities to use MIs to communicate hazard and risk, informing the public as well as decision makers. DYFI questionnaires have been filled in by millions of citizens, and have been viewed by tens of millions more, helping inculcate users to the very useful notion of MI. We document refinements to the DYFI processing and algorithmic procedures that have resulted from operational experience with the DYFI system and users. We also describe a number of automatic post-processing tools, operations, applications, and research directions, all of which utilize the extensive DYFI intensity datasets now gathered in near-real time. Finally, we discuss both the advantages and limitations of online macroseismic data collection, all of which have been fully detailed by Wald et al. (2012; Annals of Geophysics).

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

    Science.gov (United States)

    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.

  4. Seismological comparisons of solar models with element diffusion using the MHD, OPAL, and SIREFF equations of state

    International Nuclear Information System (INIS)

    Guzik, J.A.; Swenson, F.J.

    1997-01-01

    We compare the thermodynamic and helioseismic properties of solar models evolved using three different equation of state (EOS) treatments: the Mihalas, Daeppen ampersand Hummer EOS tables (MHD); the latest Rogers, Swenson, ampersand Iglesias EOS tables (OPAL), and a new analytical EOS (SIREFF) developed by Swenson et al. All of the models include diffusive settling of helium and heavier elements. The models use updated OPAL opacity tables based on the 1993 Grevesse ampersand Noels solar element mixture, incorporating 21 elements instead of the 14 elements used for earlier tables. The properties of solar models that are evolved with the SIREFF EOS agree closely with those of models evolved using the OPAL or MHD tables. However, unlike the MHD or OPAL EOS tables, the SIREFF in-line EOS can readily account for variations in overall Z abundance and the element mixture resulting from nuclear processing and diffusive element settling. Accounting for Z abundance variations in the EOS has a small, but non-negligible, effect on model properties (e.g., pressure or squared sound speed), as much as 0.2% at the solar center and in the convection zone. The OPAL and SIREFF equations of state include electron exchange, which produces models requiring a slightly higher initial helium abundance, and increases the convection zone depth compared to models using the MHD EOS. However, the updated OPAL opacities are as much as 5% lower near the convection zone base, resulting in a small decrease in convection zone depth. The calculated low-degree nonadiabatic frequencies for all of the models agree with the observed frequencies to within a few microhertz (0.1%). The SIREFF analytical calibrations are intended to work over a wide range of interior conditions found in stellar models of mass greater than 0.25M circle-dot and evolutionary states from pre-main-sequence through the asymptotic giant branch (AGB). It is significant that the SIREFF EOS produces solar models that both measure up to the stringent requirements imposed by solar oscillation observations and inferences, and are more versatile than EOS tables. copyright 1997 The American Astronomical Society

  5. Seismic attenuation and scattering tomography of rock samples using stochastic wavefields: linking seismology, volcanology, and rock physics.

    Science.gov (United States)

    Fazio, Marco; De Siena, Luca; Benson, Phillip

    2016-04-01

    Seismic attenuation and scattering are two attributes that can be linked with porosity and permeability in laboratory experiments. When measuring these two quantities using seismic waveforms recorder at lithospheric and volcanic scales the areas of highest heterogeneity, as batches of melt and zones of high deformation, produce anomalous values of the measured quantities, the seismic quality factor and scattering coefficient. When employed as indicators of heterogeneity and absorption in volcanic areas these anomalous effects become strong indicators of magma accumulation and tectonic boundaries, shaping magmatic chambers and conduit systems. We perform attenuation and scattering measurements and imaging using seismic waveforms produced in laboratory experiments, at frequencies ranging between the kHz and MHz. As attenuation and scattering are measured from the shape of the envelopes, disregarding phases, we are able to connect the observations with the micro fracturing and petrological quantities previously measured on the sample. Connecting the imaging of dry and saturated samples via these novel attributes with the burst of low-period events with increasing saturation and deformation is a challenge. Its solution could plant the seed for better relating attenuation and scattering tomography measurements to the presence of fluids and gas, therefore creating a novel path for reliable porosity and permeability tomography. In particular for volcanoes, being able to relate attenuation/scattering measurements with low-period micro seismicity could deliver new data to settle the debate about if both source and medium can produce seismic resonance.

  6. The Fusion of Financial Analysis and Seismology: Statistical Methods from Financial Market Analysis Applied to Earthquake Data

    Science.gov (United States)

    Ohyanagi, S.; Dileonardo, C.

    2013-12-01

    As a natural phenomenon earthquake occurrence is difficult to predict. Statistical analysis of earthquake data was performed using candlestick chart and Bollinger Band methods. These statistical methods, commonly used in the financial world to analyze market trends were tested against earthquake data. Earthquakes above Mw 4.0 located on shore of Sanriku (37.75°N ~ 41.00°N, 143.00°E ~ 144.50°E) from February 1973 to May 2013 were selected for analysis. Two specific patterns in earthquake occurrence were recognized through the analysis. One is a spread of candlestick prior to the occurrence of events greater than Mw 6.0. A second pattern shows convergence in the Bollinger Band, which implies a positive or negative change in the trend of earthquakes. Both patterns match general models for the buildup and release of strain through the earthquake cycle, and agree with both the characteristics of the candlestick chart and Bollinger Band analysis. These results show there is a high correlation between patterns in earthquake occurrence and trend analysis by these two statistical methods. The results of this study agree with the appropriateness of the application of these financial analysis methods to the analysis of earthquake occurrence.

  7. The 2004 Sumatra Earthquake Mw 9.3: Seismological and Geophysical Investigations in the Andaman-Nicobar Islands

    Science.gov (United States)

    Mooney, W. D.; Kayal, J.

    2007-05-01

    The December 26, 2004 Sumatra-Andaman earthquake (MW 9.3) is the fourth largest event (M>9.0) in the world during the last 100 years. It occurred by thrust faulting on the interplate thrust zone of the subducting India plate and overriding Burma platelet. The main shock rupture, ~1300 km long and ~200 km wide, propagated from north of Sumatra to Andaman - Nicobar Islands; the slow rupture generated Tsunami which killed about 300,000 people. The epicenter of the earthquake is located at 3.90N and 94.260E with a focal depth at 28 km (USGS). This mega seismic event triggered giant tsunamis that devastated the coastal regions of Indonesia, Malaysia, Thailand, Sri Lanka, India, Maldives and even the east coast of Africa. The impact of the tsunami was quite severe in India, in the coasts of Andaman and Nicobar Islands. The Air-base in the Car- Nicobar island was totally devastated by the tsunami and killed about 200 people. Macroseismic survey was carried out by different teams of GSI in North Andaman, Middle Andaman, South Andaman, Havelock Hut Bay and also in the Nicobar Islands. A maximum intensity VIII was recorded in the Andaman Islands. The mega thrust event was followed by an intense aftershock activity spreading over an area extending between 30-140N along the Andaman - Nicobar - Sumatra Island arc region. The aftershocks are distributed northwards from the epicenter of the main shock suggesting a unilateral rupture propagation. The aftershock (M >4.5) area covers a length of about 1300 km and a width of about 200 km, in a 'banana' shape. The national network (IMD) recorded almost all aftershocks M >5.0; about 350 were recorded till 31.01.2005. The Geological Survey of India (GSI) deployed six temporary seismograph stations in the Andaman and Nicobar Islands and also in Havelok and Narkunda (volcanic) islands. About 20,000 aftershocks (M >3.0) were recorded until end of March, 2005. About 1000 aftershocks (M >3.0) located by the GSI network until January 31, 2005 are studied. The aftershocks are still continuing; frequency of occurrence is, however, reduced now. Fault plane solutions suggest predominant thrust faulting in the fore arc region, and normal/strike ship in the back arc region, consistent with the regional tectonics. Crustal deformation study was carried out by various organizations. Pre- and -post earthquake vectors clearly show that islands have moved 2 to 6 meters in horizontal position towards mainland, and also there is anti-clockwise rotation. The GPS stations move southwesterly, 2 to 3 m in the Andaman Islands and 5 to 6 m in the Nicobar islands. Tidal observations indicate that there is a rise in local mean sea level of an order of 1.05 m at the Port Blair observatory. This observation is conformable with the GPS/levelling measurements that show a subsidence of the observatory to an extent of 1.1 m. The uplift and subsidence are explained by the thrust faulting involving reverse slip; uplift at the up dip edge and subsidence at the down dip on the coseismic rupture.

  8. Normal faulting in a back arc basin: Seismological characteristics of the March 2, 1987, Edgecumbe, New Zealand, Earthquake

    Science.gov (United States)

    Anderson, Helen; Smith, Euan; Robinson, Russell

    1990-04-01

    The Edgecumbe earthquake (March 2, 1987, 0142 UT, 37.92°S, 176.76°E) occurred beneath a coastal river plain a the southeastern margin of the Central Volcanic Region (CVR) of the North Island of New Zealand, a back arc basin that is widening at a geodetically determined rate of about 12 mm/yr. Its situation enabled a wide range of geological and geophysical measurements to be made of the preseismic, coseismic and postseismic processes. The estimated hypocenter and fault plane solution are consistent with the observed surface faulting. Various estimates of the seismic moment of the mainshock range from 4.3×1018 N m (from long-period P wave modelling of the first 5 s) to 10×1018 N m (from dislocation modelling of geodetic data). The variation in the values can be reasonably explained in terms of the methods used to determine them. Focal mechanisms of both mainshock and aftershocks were similar to focal mechanisms previously determined for events in the CVR and its offshore extension. Normal faulting mechanisms make up 75% of the events with the remainder strike slip (dextral assuming a northeast striking fault). The distribution of mechanisms is consistent with the regional strain field as previously determined from geodetic observations. The mainshock has been modelled as a complex event with a second subevent about 3 s after the first, with both episodes of moment release initiating at a depth of about 8 km. The Edgecumbe earthquake was preceded by a large number of foreshocks, some near the mainshock, but most in a tight cluster 35 km away to the northwest (i.e., off-strike). After the first half hour following the mainshock, swarms of aftershocks began occurring up to 50 km from the mainshock rupture, mostly along the strike of the faulting. Main rupture aftershocks were mostly located in the footwall of the main fault. A notable gap in the aftershock distribution is coincident with a geothermal field along strike of the main rupture. Swarms are common in the CVR and the whole foreshock - main shock-aftershock sequence has been interpreted as the contemporaneous occurrence of a number of swarms and a "standard" foreshock-mainshock-aftershock sequence associated with the mainshock rupture. The b values change from a low value prior to the mainshock to a very low value immediately afterwards, increasing to almost the long-term, preearthquake value during the next few days. The temporal pattern of postseismic changes in b value was mirrored by the postseismic creep on one of the fault segments, which closely followed a Jeffreys-Lomnitz law, suggesting that both phenomena were responses to a viscoelastic relaxation of the regional stress. Comparisons with similarly sized normal faulting events elsewhere show that the most unusual feature of the Edgecumbe earthquake was the high level of foreshock activity in two separate clusters 35 km apart. This foreshock activity and the widespread nature of the aftershocks are attributed to a level of stress throughout the CVR that is permanently close to the critical level for shear failure. A mechanism that is unknown, but undoubtedly related to volcanic or plutonic processes and probably involving fluids, enables stress changes within the CVR to be rapidly transmitted over tens of kilometres.

  9. Tracking Down the Causes of Recent Induced and Natural Intraplate Earthquakes with 3D Seismological Analyses in Northwest Germany

    Science.gov (United States)

    Uta, P.; Brandes, C.; Boennemann, C.; Plenefisch, T.; Winsemann, J.

    2015-12-01

    Northwest Germany is a typical low strain intraplate region with a low seismic activity. Nevertheless, 58 well documented earthquakes with magnitudes of 0.5 - 4.3 affected the area in the last 40 years. Most of the epicenters were located in the vicinity of active natural gas fields and some inside. Accordingly, the earthquakes were interpreted as a consequence of hydrocarbon recovery (e.g. Dahm et al. 2007, Bischoff et al. 2013) and classified as induced events in the bulletins of the Federal Institute for Geosciences and Natural Resources (BGR). The two major ones have magnitudes of 4.3 and 4.0. They are the strongest earthquakes ever recorded in Northern Germany. Consequently, these events raise the question whether the ongoing extraction itself can cause them or if other natural tectonic processes like glacial isostatic adjustment may considerably contribute to their initiation. Recent studies of Brandes et al. (2012) imply that lithospheric stress changes due to post glacial isostatic adjustment might be also a potential natural cause for earthquakes in Central Europe. In order to better analyse the earthquakes and to test this latter hypothesis we performed a relocalization of the events with the NonLinLoc (Lomax et al. 2000) program package and two differently scaled 3D P-wave velocity models. Depending on the station coverage for a distinct event, either a fine gridded local model (88 x 73 x 15 km, WEG-model, made available by the industry) or a coarse regional model (1600 x 1600 x 45 km, data from CRUST1.0, Laske et al. 2013) and for some cases a combination of both models was used for the relocalization. The results confirm the trend of the older routine analysis: The majority of the events are located at the margins of the natural gas fields, some of them are now located closer to them. Focal depths mostly vary between 3.5 km and 10 km. However, for some of the events, especially for the older events with relatively bad station coverage, the error bars for the focal depth are large. To prevent uncertainties in focal depths and focal mechanisms we generate synthetic seismograms depending on the reflectivity method to get a more precise position of the hypocenters. For hypocenters deeper than 10 km we speculate that these events might be potential natural earthquakes.

  10. Using the seismology of non-magnetic chemically peculiar stars as a probe of dynamical processes in stellar interiors

    OpenAIRE

    Turcotte, S.

    2005-01-01

    Chemical composition is a good tracer of hydrodynamical processes that occur in stars as they often lead to mixing and particle transport. By comparing abundances predicted by models and those observed in stars we can infer some constraints on those mixing processes. As pulsations in stars are often very sensitive to chemical composition, we can use asteroseismology to probe the internal chemical composition of stars where no direct observations are possible. In this paper I focus on main seq...

  11. How citizen seismology is transforming rapid public earthquake information: the example of LastQuake smartphone application and Twitter QuakeBot

    Science.gov (United States)

    Bossu, R.; Etivant, C.; Roussel, F.; Mazet-Roux, G.; Steed, R.

    2014-12-01

    Smartphone applications have swiftly become one of the most popular tools for rapid reception of earthquake information for the public. Wherever someone's own location is, they can be automatically informed when an earthquake has struck just by setting a magnitude threshold and an area of interest. No need to browse the internet: the information reaches you automatically and instantaneously! One question remains: are the provided earthquake notifications always relevant for the public? A while after damaging earthquakes many eyewitnesses scrap the application they installed just after the mainshock. Why? Because either the magnitude threshold is set too high and many felt earthquakes are missed, or it is set too low and the majority of the notifications are related to unfelt earthquakes thereby only increasing anxiety among the population at each new update. Felt and damaging earthquakes are the ones of societal importance even when of small magnitude. LastQuake app and Twitter feed (QuakeBot) focuses on these earthquakes that matter for the public by collating different information threads covering tsunamigenic, damaging and felt earthquakes. Non-seismic detections and macroseismic questionnaires collected online are combined to identify felt earthquakes regardless their magnitude. Non seismic detections include Twitter earthquake detections, developed by the USGS, where the number of tweets containing the keyword "earthquake" is monitored in real time and flashsourcing, developed by the EMSC, which detect traffic surges on its rapid earthquake information website caused by the natural convergence of eyewitnesses who rush to the Internet to investigate the cause of the shaking that they have just felt. We will present the identification process of the felt earthquakes, the smartphone application and the 27 automatically generated tweets and how, by providing better public services, we collect more data from citizens.

  12. A new approach to the unrest and subsequent eruption at El Hierro Island (2011) based on petrological, seismological, geodetical and gravimetric data

    Science.gov (United States)

    Meletlidis, Stavros; Di Roberto, Alessio; Domínguez Cerdeña, Itahiza; Pompilio, Massimo; García-Cañada, Laura; Bertagnini, Antonella; Benito Saz, Maria Angeles; Del Carlo, Paola; Sainz-Maza Aparicio, Sergio; Lopez Moreno, Carmen; Moure García, David

    2014-05-01

    A shallow submarine eruption took place on 10th October 2011, about 1.8 km off the coast of La Restinga, a small village located in El Hierro (Canary Islands, Spain). The eruption lasted for about four months and ended by early March 2012. The eruption was preceded by an unrest episode that initiated about three months before, in July 2011, and characterized by more than 10,000 localized earthquakes accompanied by up to 5 cm of vertical ground deformation. In the Canary Islands, this event represents the first case of an eruption that was monitored since the unrest to the end by the monitoring network of IGN (Instituto Geográfico National), providing a huge dataset that includes geophysical (seismic, magnetic and gravimetric), geodetic, geochemistry and petrological data. In this work we use the seismic, GPS and gravity records collected by IGN along with the petrological data derived from the study of various lava balloons, scoriaceous fragments and ash.Geophysical and geochemical monitoring tools provide a variety of information that need to be interpreted in terms of magma movement and/or interaction of magma with host rocks. We present a model, based on this data, which describes the intrusion and ascent of the magma. According to this model, a major intrusion beneath and around preexisting high-density magmatic bodies, localized in the central sector of the island, led to an eruption in the Southern sector of the island. After a failed attempt to reach the surface, while various dykes were emplaced, through a low fractured area in the Central and Northern parts of the island, the ascending magma finally found its way in the submarine area of La Restinga, in the South rift zone, at a depth of 350 m below sea level. Feeding of the eruption was achieved by the ascension of an important volume of material from the upper mantle which was emplaced near the crust-mantle boundary. However, the very energetic post-eruptive unrests - we had five episodes up today with high magnitude earthquake sequences and higher ground deformation than the one occurred during the eruption - suggest that only a small part of the material was emitted. And probably are due to new dyke or sill emplacement with material provided from the same intrusion in the base of the island.

  13. Table-top earthquakes; a demonstration of seismology for teachers and students that can be used to augment lessons in earth science, physics, math, social studies, geography

    Science.gov (United States)

    Lahr, J.C.

    1998-01-01

    The apparatus consists of a heavy object that is dragged steadily with an elastic cord. Although pulled with a constant velocity, the heavy object repeatedly slides and then stops. A small vibration sensor, attached to a computer display, graphically monitors this intermittent motion. 2 This intermittent sliding motion mimics the intermittent fault slippage that characterizes the earthquake fault zones. In tectonically active regions, the Earth's outer brittle shell, which is about 50 km thick, is slowly deformed elastically along active faults. As the deformation increases, stress also increases, until fault slippage releases the stored elastic energy. This process is called elastic rebound. Detailed instructions are given for assembly and construction of this demonstration. Included are suggested sources for the vibration sensor (geophone) and the computer interface. Exclusive of the personal computer, the total cost is between $125 and $150. I gave a talk at the Geological Society of America's Cordilleran Section Centennial meeting on June 2, 1999. The slides show how this table-top demonstration can be used to help meet many of the K-12 teaching goals described in Benchmarks for Science Literacy (American Association for the Advancement of Science, 1993).

  14. The IRIS DMC: Perspectives on Real-Time Data Management and Open Access From a Large Seismological Archive: Challenges, Tools, and Quality Assurance

    Science.gov (United States)

    Benson, R. B.

    2007-05-01

    The IRIS Data Management Center, located in Seattle, WA, is the largest openly accessible geophysical archive in the world, and has a unique perspective on data management and operational practices that gets the most out of your network. Networks scale broad domains in time and space, from finite needs to monitor bridges and dams to national and international networks like the GSN and the FDSN that establish a baseline for global monitoring and research, the requirements that go into creating a well-tuned DMC archive treat these the same, building a collaborative network of networks that generations of users rely on and adds value to the data. Funded by the National Science Foundation through the Division of Earth Sciences, IRIS is operated through member universities and in cooperation with the USGS, and the DMS facility is a bridge between a globally distributed collaboration of seismic networks and an equally distributed network of users that demand a high standard for data quality, completeness, and ease of access. I will describe the role that a perpetual archive has in the life cycle of data, and how hosting real-time data performs a dual role of being a hub for continuous data from approximately 59 real-time networks, and distributing these (along with other data from the 40-year library of available time-series data) to researchers, while simultaneously providing shared data back to networks in real- time that benefits monitoring activities. I will describe aspects of our quality-assurance framework that are both passively and actively performed on 1100 seismic stations, generating over 6,000 channels of regularly sampled data arriving daily, that data providers can use as aids in operating their network, and users can likewise use when requesting suitable data for research purposes. The goal of the DMC is to eliminate bottlenecks in data discovery and shortening the steps leading to analysis. This includes many challenges, including keeping metadata current, tools for evaluating and viewing them, along with measuring and creating databases of other performance metrics and how monitoring them closer to real- time helps reduce operation costs, creates a richer repository, and eliminates problems over generations of duty cycles of data usage. I will describe a new resource, called the Nominal Response Library, which hopes to provide accurate and representative examples of sensor and data logger configurations that are hosted at the DMC and constitute a high-graded subset for crafting your own metadata. Finally, I want to encourage all network operators who do not currently submit SEED format data to an archive to consider these benefits, and briefly discuss how robust transfer mechanisms that include Earthworm, LISS, Antelope, NRTS and SeisComp, to name a few, can assist you in contributing your network data and help create this enabling virtual network of networks. In this era of high performance Internet capacity, the process that enables others to share your data and allows you to utilize external sources of data is nearly seamless with your current mission of network operation.

  15. Modeling and Inversion of three-dimensional crustal structures beneath the Pyrenees and their foreland basins based upon geological, gravimetric and seismological data

    Science.gov (United States)

    Spangenberg, Hannah; Chevrot, Sébastien; Courrioux, Gabriel; Guillen, Antonio

    2017-04-01

    Our goal is to obtain a three-dimensional (3D) model of mass density and seismic velocities beneath the Pyrenees and their foreland basins (Aquitaine and Ebro basins), which accounts for all the geological and geophysical information available for that region. This model covers the whole mountain range going from the Atlantic Ocean to the Mediterranean Sea, and from the Iberian range to the Massif Central. The model is described by different units: the lower, middle, and upper crusts, the accretionary prism, and the consolidated and unconsolidated sediment layers. Furthermore, a sub-continental, serpentinized European mantle is introduced to describe the exhumed mantle bodies which are responsible for the positive Bouguer gravity anomalies in the western Pyrenees. We build a first 3D model using all the geological information: drill-hole surveys, seismic sections, and the geological map. We use the potential field method implemented in Geomodeler to interpolate these geological data. However, these data are too sparse to build a model that explains seismic travel times or gravimetric data, especially the Labourd and the St. Gaudens Bouguer gravity anomalies. In addition, inconsistencies between the different data sets exist. We thus add by trial and error additional data points, comparing modeled and observed Bouguer gravimetric anomalies. The result of this procedure is a 3D geological model that respects the geological data and explains the measured Bouguer gravimetric anomalies. In a second step, we use this model to determine the average density and seismic velocities inside each geological unit assuming uniform layers. To constrain the seismic velocities we use travel time picks extracted from the bulletin of the Pyrenean seismicity released by the Observatoire Midi Pyrenées. In a third step, we use this 3D a priori model in a Monte Carlo inversion to invert jointly gravimetric data and seismic travel times from the bulletin. This probabilistic approach yields detailed information about the sedimentary foreland basins and the crustal structures beneath the Pyrenees. We will present and discuss different key steps of the construction of the 3D model of the Pyrenees. We will also compare selected cross-sections extracted from this model to the ECORS profiles, as well as CCP stacks of receiver functions along several PYROPE transects. Keywords: Pyrenees, 3D modeling, gravity, seismic tomography, joint inversion

  16. GPS Versus Seismological Observations in two Seismogenic Zones in the Adria-Alps- Pannon System; Block Motion vs. Diffuse Deformation, Increased Earthquake Potential vs. Aseismic Slip

    Science.gov (United States)

    Grenerczy, G.; Bus, Z.; Toth, L.; Monus, P.

    2008-12-01

    The tectonic activity, seismicity and the associated seismic hazard is highly variable in the Adria-Alps-Pannon region. The engine of the system is the Adria microplate that compresses a puzzle of crustal blocks towards the European Platform. Based on seismicity and data of continuous and campaign style GPS measurements between 1991 and 2007 we investigated the existence of different blocks and their present kinematics. At the resolution and signal level we have, deformation seems to be more diffuse and block motion is no longer recognizable over the Pannonian basin towards the Carpathains. Although towards the basin seismicity decreases to moderate, the vulnerability is still high, as three capital cities are located near to the two most active seismic zones in this subregion. Each cities and their suburbs produce about 30- 40 % of the GDP of the respective countries. In the second par of our analysis these two seismically active areas, the Mur-Murz and Central Pannonian zones, are investigated. Uniform strain rates and relative displacements were calculated for these regions. The GPS data confirm the mostly left lateral strike slip character of the Mur-Murz fault zone and suggest a contraction between the eastward moving Alpine-North Pannonian unit and the Carpathians. The computation of the seismic strain rate was based on the Kostrov summation. The averaged unit norm seismic moment tensor, which describes the characteristic style of deformation, has been obtained by using the available focal mechanism solutions, whereas the annual seismic moment release showing the rate of the deformation was estimated using the catalogs of historical and recent earthquakes. Our analysis reveals that in both zones the geodetic strain rate is significantly larger than the seismic deformation. Based on the weakness of the lithosphere, the stress magnitudes and the regional features of seismicity, we suggest that the low value of the seismic/geodetic strain rate ratio in the Central Pannonian and probably also in the Mur-Murz zone can be attributed to the aseismic release of the prevailing compressive stress and not to an overdue major earthquake.

  17. Twenty-First Water Reactor Safety Information Meeting. Volume 3, Primary system integrity; Aging research, products and applications; Structural and seismic engineering; Seismology and geology: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Monteleone, S. [comp.] [Brookhaven National Lab., Upton, NY (United States)

    1994-04-01

    This three-volume report contains 90 papers out of the 102 that were presented at the Twenty-First Water Reactor Safety Information Meeting held at the Bethesda Marriott Hotel, Bethesda, Maryland, during the week of October 25-27, 1993. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from France, Germany, Japan, Russia, Switzerland, Taiwan, and United Kingdom. The titles of the papers and the names of the authors have been updated and may differ from those that appeared in the final program of the meeting. Selected papers were indexed separately for inclusion in the Energy Science and Technology Database.

  18. MODELING OBSERVED DECAY-LESS OSCILLATIONS AS RESONANTLY ENHANCED KELVIN–HELMHOLTZ VORTICES FROM TRANSVERSE MHD WAVES AND THEIR SEISMOLOGICAL APPLICATION

    Energy Technology Data Exchange (ETDEWEB)

    Antolin, P.; De Moortel, I. [School of Mathematics and Statistics, University of St. Andrews, St. Andrews, Fife KY16 9SS (United Kingdom); Van Doorsselaere, T. [Centre for mathematical Plasma Astrophysics, Mathematics Department, KU Leuven, Celestijnenlaan 200B bus 2400, B-3001 Leuven (Belgium); Yokoyama, T., E-mail: patrick.antolin@st-andrews.ac.uk [Department of Earth and Planetary Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2016-10-20

    In the highly structured solar corona, resonant absorption is an unavoidable mechanism of energy transfer from global transverse MHD waves to local azimuthal Alfvén waves. Due to its localized nature, direct detection of this mechanism is extremely difficult. Yet, it is the leading theory explaining the observed fast damping of the global transverse waves. However, at odds with this theoretical prediction are recent observations that indicate that in the low-amplitude regime such transverse MHD waves can also appear decay-less, a still unsolved phenomenon. Recent numerical work has shown that Kelvin–Helmholtz instabilities (KHI) often accompany transverse MHD waves. In this work, we combine 3D MHD simulations and forward modeling to show that for currently achieved spatial resolution and observed small amplitudes, an apparent decay-less oscillation is obtained. This effect results from the combination of periodic brightenings produced by the KHI and the coherent motion of the KHI vortices amplified by resonant absorption. Such an effect is especially clear in emission lines forming at temperatures that capture the boundary dynamics rather than the core, and reflects the low damping character of the local azimuthal Alfvén waves resonantly coupled to the kink mode. Due to phase mixing, the detected period can vary depending on the emission line, with those sensitive to the boundary having shorter periods than those sensitive to the loop core. This allows us to estimate the density contrast at the boundary.

  19. Modeling of a historical earthquake in Erzincan, Turkey (Ms 7.8, in 1939) using regional seismological information obtained from a recent event

    Science.gov (United States)

    Karimzadeh, Shaghayegh; Askan, Aysegul

    2018-04-01

    Located within a basin structure, at the conjunction of North East Anatolian, North Anatolian and Ovacik Faults, Erzincan city center (Turkey) is one of the most hazardous regions in the world. Combination of the seismotectonic and geological settings of the region has resulted in series of significant seismic activities including the 1939 (Ms 7.8) as well as the 1992 (Mw = 6.6) earthquakes. The devastative 1939 earthquake occurred in the pre-instrumental era in the region with no available local seismograms. Thus, a limited number of studies exist on that earthquake. However, the 1992 event, despite the sparse local network at that time, has been studied extensively. This study aims to simulate the 1939 Erzincan earthquake using available regional seismic and geological parameters. Despite several uncertainties involved, such an effort to quantitatively model the 1939 earthquake is promising, given the historical reports of extensive damage and fatalities in the area. The results of this study are expressed in terms of anticipated acceleration time histories at certain locations, spatial distribution of selected ground motion parameters and felt intensity maps in the region. Simulated motions are first compared against empirical ground motion prediction equations derived with both local and global datasets. Next, anticipated intensity maps of the 1939 earthquake are obtained using local correlations between peak ground motion parameters and felt intensity values. Comparisons of the estimated intensity distributions with the corresponding observed intensities indicate a reasonable modeling of the 1939 earthquake.

  20. Active crustal deformation of the El Salvador Fault Zone by integrating geodetic, seismological and geological data: application in seismic hazard assessment

    Science.gov (United States)

    Staller, A.; Benito, B.; Martínez-Díaz, J.; Hernández, D.; Hernández-Rey, R.

    2013-05-01

    El Salvador, Central America, is part of the Chortis block in the northwestern boundary of the Caribbean plate. This block is interacting with a diffuse triple junction point with the Cocos and North American plates. Among the structures that cut the Miocene to Pleistocene volcanic deposits stands out the El Salvador Fault Zone (ESFZ): It is oriented in N90-100E direction, and it is composed of several structural segments that deform Quaternary deposits with right-lateral and oblique slip motions. The ESFZ is seismically active and capable of producing earthquakes such as the February 13, 2001 with Mw 6.6 (Martínez-Díaz et al., 2004), that seriously affected the population, leaving many casualties. This structure plays an important role in the tectonics of the Chortis block, since its motion is directly related to the drift of the Caribbean plate to the east and not with the partitioning of the deformation of the Cocos subduction (here not coupled) (Álvarez-Gómez et al., 2008). Together with the volcanic arc of El Salvador, this zone constitutes a weakness area that allows the motion of forearc block toward the NW. The geometry and the degree of activity of the ESFZ are not studied enough. However their knowledge is essential to understand the seismic hazard associated to this important seismogenic structure. For this reason, since 2007 a GPS dense network was established along the ESFZ (ZFESNet) in order to obtain GPS velocity measurements which are later used to explain the nature of strain accumulation on major faults along the ESFZ. The current work aims at understanding active crustal deformation of the ESFZ through kinematic model. The results provide significant information to be included in a new estimation of seismic hazard taking into account the major structures in ESFZ.

  1. Geological and Seismological Analysis of the 13 February 2001 Mw 6.6 El Salvador Earthquake: Evidence for Surface Rupture and Implications for Seismic Hazard

    OpenAIRE

    Canora Catalán, Carolina; Martínez Díaz, José J.; Villamor Pérez, María Pilar; Berryman, K.R.; Álvarez Gómez, José Antonio; Pullinger, Carlos; Capote del Villar, Ramón

    2010-01-01

    The El Salvador earthquake of 13 February 2001 (Mw 6.6) caused tectonic rupture on the El Salvador fault zone (ESFZ). Right-lateral strike-slip surface rupture of the east–west trending fault zone had a maximum surface displacement of 0.60 m. No vertical component was observed. The earthquake resulted in widespread landslides in the epicentral area, where bedrock is composed of volcanic sediments, tephra, and weak ignimbrites. In the aftermath of the earthquake, widespread dama...

  2. Site Effect Assessment of the Gros-Morne Hill Area in Port-au-Prince, Haiti, Part A: Geophysical-Seismological Survey Results

    Directory of Open Access Journals (Sweden)

    Sophia Ulysse

    2018-04-01

    Full Text Available After the M = 7.0 Haiti earthquake in 2010, many teams completed seismic risk studies in Port-au-Prince to better understand why this not extraordinarily strong event had induced one of the most severe earthquake disasters in history (at least in the Western World. Most highlighted the low construction quality as the main cause for the disaster, but some also pointed to possible soil and topographic amplification effects, especially in the lower and central parts of Port-au-Prince (e.g., close to the harbor. However, very detailed local studies of such site effects have not been completed yet. A Belgian-Haitian collaboration project was established in order to develop a detailed local seismic hazard study for Gros-Morne hill located in the district of Pétion-Ville, southeast of Port-au-Prince. In order to have a better understanding of the amplification on the Gros-Morne hill, in the southeastern part of Port-au-Prince, site effects were investigated by using near surface geophysical methods. The horizontal to vertical spectral ratio technique was applied to ambient vibrations and earthquake data, and multichannel analysis of surface waves and P-wave refraction tomography calculation were applied to seismic data. Standard spectral ratios were computed for the S-wave windows of the earthquake data recorded by a small temporary seismic network. Electrical resistivity tomography profiles were also performed in order to image the structure of the subsurface and detect the presence of water, if any. The spectral ratio results generally show low to medium (1.5–6 resonance amplitudes at one or several different resonance frequencies (for the same site, between 0.5 and 25 Hz. At most of the investigated sites, the fundamental resonance frequency varies between 7 and 10 Hz. By using the multichannel surface wave analyses of the seismic data, we were able to determine shear wave velocities ranging between 200 and 850 m/s, up to a depth of about 15–20 m. From the refraction analysis, we were able to delineate P-waves velocities of 500 to 1500–2000 m/s at the studied sites. The outputs were locally compared with the resistivity data from the electrical profiles. Thus, the overall data indicate a moderate site effect at Gros-Morne hill, with a great variability in site amplification distribution. Initial estimates of local site effects were made on the basis of those outputs and the earthquake recordings. Our results are finally discussed with respect to outputs and interpretations that had been published earlier for the same site. Those results only partly confirm the strong seismic amplification effects highlighted by previous papers for this hill site, which had been explained by the effects of the local topographic and soil characteristics.

  3. Relationships between seismic wave-Speed, density, and electrical conductivity beneath Australia from seismology, mineralogy, and laboratory-based conductivity profiles

    DEFF Research Database (Denmark)

    Khan, A.; Koch, S.; Shankland, T. J.

    2015-01-01

    We present maps of the three-dimensional density (ρ), electrical conductivity (σ), and shear-wave speed (VS) structure of the mantle beneath Australia and surrounding ocean in the depth range of 100–800 km. These maps derived from stochastic inversion of seismic surface-wave dispersion data...... shear-wave speeds, low densities, and high conductivities. This trend appears to continue to depths well below 300 km. The slow-fast shear-wave speed distribution found here is also observed in independent seismic tomographic models of the Australian region, whereas the coupled slow-fast shear......-wave speed, low-high density, and high-low electrical conductivity distribution has not been observed previously. Toward the bottom of the upper mantle at 400 km depth marking the olivine ⃗ wadsleyite transformation (the “410–km” seismic discontinuity), the correlation between VS, ρ, and σ weakens...

  4. The salt stock of the Jura bassin in Ostholstein. A seismologic re-interpretation; Der Salzstock des ostholsteinischen Juratroges. Eine seismische Re-Interpretation

    Energy Technology Data Exchange (ETDEWEB)

    Brink, H.J.; Baykulov, M.; Gajewski, D.; Yoon, Mi-Kyung [Hamburg Univ. (Germany). Inst. fuer Geophysik

    2008-10-23

    The developing age of the Permian salt stocks in Schleswig-Holstein (Federal Republic of Germany) reaches from the Trias over the Jura up to the Tertiary period. In the context of the DGMK project 577-1, the reflection-rich salt dome in the East Holstein Jura was investigated seismically by means of the CRS method and speed tomography. These measurements enable the interpretation of a structural style with a substantial tectonically compressive component. Magnetotelluric measurements point to potential natural gas source rocks. The drift of the Permian salt contributes to the contact support of new red sandstone on the pre-salinar layers. Migration ways are opened which contributed to a filling of structurally high new red sandstone reservoirs in small depths.

  5. Report on the International Training Course on Seismology and Seismic Hazard Assessment, Nairobi, Kenya, October 05 to November 08, 1997, 42 pp. + annexes

    OpenAIRE

    P. Bormann;  

    1998-01-01

    Additional keywords: zirkular, Programm, Hintergrund-Informationen, Teilnehmer, Lektoren, Kursauswertung, Schlussfolgerungen, Empfehlungen, Finanzabrechnung, Workshops, nationale Abende, Nachfolgestudien, Zertifikate

  6. Seismological and structural constraints on the 2011-2013, Mmax 4.6 seismic sequence at the south-eastern edge of the Calabrian arc (North-eastern Sicily, Italy)

    Science.gov (United States)

    Cammarata, Laura; Catalano, Stefano; Gambino, Salvatore; Palano, Mimmo; Pavano, Francesco; Romagnoli, Gino; Scaltrito, Antonio; Tortorici, Giuseppe

    2018-01-01

    Between June 2011 and September 2013, the Nebrodi Mountains region was affected by a seismic swarm consisting of > 2700 events with local magnitude 1.3 ≤ ML ≤ 4.6 and located in the 5-9 km depth interval. The seismic swarm defines a seismogenetic volume elongated along the E-W direction and encompasses the NW-SE-oriented tectonic boundary between the Calabrian arc (north-eastward) and the Sicilide units (south-westward). By exploring the recent tectonic deformation and the seismic behavior of the region, this study aims at providing additional constraints on the seismogenetic faults at the southern termination of the Calabrian arc. Waveform similarities analysis allowed observing that 45% of the whole dataset can be grouped into six different families of seismic events. Earthquake multiplet families are mainly located in the eastern part of the seismogenetic volume. We suggest that such a feature is responsive to the lateral lithological variations as highlighted by geology (at the surface) and P-wave seismic tomography (at depth of 10 km). Stress tensor inversions performed on FPSs indicate that the investigated region is currently subject to a nearly biaxial stress state in an extensional regime, such that crustal stretching occurs along both NW-SE and NE-SW directions. Accordingly, mesoscale fault geometries and kinematics analyses evidence that a younger normal faulting stress regime led to a tectonic negative inversion by replacing the pre-existing strike-slip one. Based on our results and findings reported in recent literature, we refer such a crustal stretching to mantle upwelling process (as evidenced by diffuse mantle-derived gas emissions) coupled with a tectonic uplift involving north-eastern Sicily since Middle Pleistocene. Moreover, seismic swarms striking the region would be related to the migration of mantle and sub-crustal fluids toward the surface along the complex network of tectonic structures cutting the crust and acting as pathways.

  7. Seismologic study of Los Hum eros geothermal field, Pueblo, Mexico. Part I: Seismicity, source mechanisms and stress distribution; Estudio sismologico del campo geotermico de Los Humeros, Puebla, Mexico. Parte I: Sismicidad, mecanismos de fuente y distribucion de esfuerzos

    Energy Technology Data Exchange (ETDEWEB)

    Lermo, Javier; Antayhua, Yanet [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, Mexico D.F (Mexico)]. E-Mail: jles@pumas.iingen.unam.mx; Quintanar, Luis [Instituto de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico D.F (Mexico); Lorenzo, Cecilia [Gerencia de Proyectos Geotermoelectricos, Comision Federal de Electricidad, Michoacan (Mexico)

    2008-01-15

    The distribution of earthquakes at the surface and at depth in the Los Humeros geothermal field, Puebla (Mexico), is analyzed from 1997-2004. Data for 95 earthquakes were registered at more than five permanent and temporary stations installed by the Comision Federal de Electricidad and the Instituto de Ingenieria of the Universidad Nacional Autonoma de Mexico. The duration magnitudes of the quakes are equal to or lower than 3.6 Md and the focal depths do not exceed 4.0 km. Simple focal mechanisms and moment tensor inversions were made, and the number of earthquakes registered by two stations of the permanent network (numbers S05, S06) was compared with water-injection and steam-production volumes over a certain period. The results at the surface and at depth show seismic activity occurring in the northern zone of the field around injection wells I29 (well H-29) and I38 (well H-38); whereas, the simple focal mechanisms and moment tensors demonstrate stresses of heterogeneous origin, suggesting that part of the seismic activity in Los Humeros is probably induced, mainly by injecting water. [Spanish] Se analiza la distribucion en superficie y en profundidad de los sismos ocurridos en el campo geotermico de Los Humeros, Puebla (Mexico), durante el periodo 1997-2004. Los datos corresponden a 95 sismos registrados por mas de cinco estaciones permanentes y temporales instaladas por la Comision Federal de Electricidad y el Instituto de Ingenieria de la Universidad Nacional Autonoma de Mexico, cuyas magnitudes de duracion son menores o iguales a 3.6 Md y profundidades focales que no sobrepasan los 4.0 km. Asimismo, se realizaron mecanismos focales simples y de inversion de tensor de momento, y se comparo el numero de sismos registrados por dos estaciones de la red permanente (numeros S05, S06) con la inyeccion de agua y la produccion de vapor durante cierto tiempo. Los resultados en superficie y en profundidad muestran actividad sismica en la zona norte del campo, alrededor de los pozos inyectores I29 (pozo H-29) e I38 (pozo H-38), mientras que los mecanismos focales simples y de tensor de momento evidencian esfuerzos de origen heterogeneo, sugiriendo que parte de la actividad sismica ocurrida en Los Humeros puede haber sido inducida principalmente por el proceso de inyeccion de agua al subsuelo del campo geotermico.

  8. Observational studies in South African mines to mitigate seismic risks: a mid-project progress report

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2013-10-01

    Full Text Available -322. Utsu, T., 2003, Centennial Report of Japan. Part 2. Historical development of Seismology in Japan. International Handbook of Earthquake & Engineering Seismology, Part B, W. Lee, P. Jennings, C. Kisslinger and H. Kanamori (eds), Academic Press...

  9. Seismic exploration?scale velocities and structure from ambient seismic noise (>1?Hz)

    NARCIS (Netherlands)

    Draganov, D.S.; Campman, X.; Thorbecke, J.W.; Verdel, A.; Wapenaar, C.P.A.

    2013-01-01

    The successful surface waves retrieval in solid?Earth seismology using long?time correlations and subsequent tomographic images of the crust have sparked interest in extraction of subsurface information from noise in the exploration seismology. Subsurface information in exploration seismology is

  10. Seismic exploration-scale velocities and structure from ambient seismic noise (>1 Hz)

    NARCIS (Netherlands)

    Draganov, D.; Campman, X.; Thorbecke, J.; Verdel, A.; Wapenaar, K.

    2013-01-01

    The successful surface waves retrieval in solid-Earth seismology using long-time correlations and subsequent tomographic images of the crust have sparked interest in extraction of subsurface information from noise in the exploration seismology. Subsurface information in exploration seismology is

  11. Seismologic study of Los Humeros geothermal field, Puebla, Mexico. Part II: Seismic tomography by attenuation of coda waves (Qc-1) of local earthquakes; Estudio sismologico del campo geotermico de Los Humeros, Puebla, Mexico. Parte II: Tomografia sismica por atenuacion a partir de ondas de coda (Qc-1) de sismos locales

    Energy Technology Data Exchange (ETDEWEB)

    Antayhua, Yanet; Lermo, Javier [Instituto de Ingenieria, Universidad Nacional Autonoma de Mexico, D.F (Mexico); Carlos, Vargas [Departamento de Geociencias, Universidad Nacional de Colombia (Colombia)]. E-mail: jles@pumas.iingen.unam.mx

    2008-07-15

    In the Los Humeros geothermal field, Puebla, seismic tomography has been studied using the attenuation of coda waves (Qc{sup -1}). Ninety-five local earthquakes (Md{<=}3.6) have been used with depths up to 4.0 km registered in the seismic network stations from December 1997 to December 2004. A simple backscattering model was used, filtered in four ranks of frequencies (2, 4, 6, and 8 Hz) and one window of 5 seconds. For the 3D-representation, we used an approximation based on first-order scattering of ellipsoids. The results show that values of Qc for the used frequencies have a frequency dependency shown in the equation: Qc=24{+-}12f{sup 0.86}{+-}{sup 0.06}, where the low values of Qc were observed in the zone of higher seismic and tectonic activity and in the location of injection and production wells. The high values are located in the periphery of the geothermal field. The distribution of the Qc{sup -1} attenuation in 3D and 2D shows the anomalies of high-seismic attenuation are located in the north, south, and southwestern ends of the zone presently under operation, at depths greater than 2.5 km. [Spanish] Para realizar la tomografia sismica por atenuacion de ondas de coda (Qc{sup -1}) en el campo geotermico de Los Humeros, Puebla, se han utilizado 95 sismos locales (Md{<=}3.6) con profundidades hasta 4.0 km, registrados en las estaciones de su red sismica, durante el periodo de diciembre 1997 a diciembre 2004. Se utilizo el modelo de retrodispersion simple, filtrados en cuatro rangos de frecuencias (2, 4, 6, y 8 Hz) y una ventana de 5 segundos. Para la representacion en 3D, se utilizo una aproximacion basada en elipsoides que representan dispersion de primer orden. Los resultados muestran que los valores de Qc para las frecuencias utilizadas tienen una dependencia con la frecuencia de la forma: Qc=24{+-}12f{sup 0.86}{+-}{sup 0.06}, donde los valores bajos de Qc fueron observados en la zona de mayor actividad sismica y en la ubicacion de pozos inyectores y productores, mientras que los valores altos se observaron en la periferia del campo geotermico. Asimismo, la distribucion de la atenuacion Qc{sup -1} en 3D y 2D muestra que las anomalias de alta atenuacion sismica se ubican en los extremos norte, sur y suroeste de la zona de explotacion actual, y a profundidades mayores a 2.5 km. Palabras clave: Los Humeros, atenuacion intrinseca, ondas de coda, tomografia sismica.

  12. Earthquakes in the Federal Republic of Germany in 1983

    International Nuclear Information System (INIS)

    Henger, M.; Leydecker, G.

    1988-01-01

    The report summarizes the regional reports of the seismological observatories for the year 1983. There was no serious earthquake so far in the F.R.G. The data are presented in the form of maps showing the seismic centers in West Germany (including marginal regions). Explanations of seismological terminology and abbreviations used are given for the general reader. (DG) [de

  13. Seismic waves and sources Ari Ben-Menahem and Sarva Jit Singh (Book review)

    NARCIS (Netherlands)

    Berg, A.P. van den

    1984-01-01

    In recent years several excellent books on the subject of theoretical seismology have appeared on the market. This might be seen as an indication that seismology has finally become a full grown branch of physics since its foundations were laid, theoretically and empirically, in the 19th

  14. Earthquakes and Earthquake Engineering. LC Science Tracer Bullet.

    Science.gov (United States)

    Buydos, John F., Comp.

    An earthquake is a shaking of the ground resulting from a disturbance in the earth's interior. Seismology is the (1) study of earthquakes; (2) origin, propagation, and energy of seismic phenomena; (3) prediction of these phenomena; and (4) investigation of the structure of the earth. Earthquake engineering or engineering seismology includes the…

  15. Waveletový rozklad seismologických signálů

    Czech Academy of Sciences Publication Activity Database

    Častová, N.; Kaláb, Zdeněk

    2003-01-01

    Roč. 3, č. 2 (2003), s. 51-60 ISSN 1213-1962. [New results of the seismological, geophysical and geotechnical research/12./. Ostrava, 01.04.2003-03.04.2003] R&D Projects: GA AV ČR KSK3012103 Institutional research plan: CEZ:AV0Z3086906 Keywords : seismology * wavelet transform Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  16. Evaluation of vibratory ground motion at nuclear power plant sites

    International Nuclear Information System (INIS)

    Hofmann, R.B.; Greeves, J.T.

    1978-01-01

    The evaluation of vibratory ground motion at nuclear power plant sites requires the cooperative effort of scientists and engineers in several disciplines. These include seismology, geology, geotechnical engineering and structural engineering. The Geosciences Branch of the NRC Division of Site Safety and Environmental Analysis includes two sections, the Geology/Seismology Section and the Geotechnical Engineering Section

  17. CORSSA: The Community Online Resource for Statistical Seismicity Analysis

    Science.gov (United States)

    Michael, Andrew J.; Wiemer, Stefan

    2010-01-01

    Statistical seismology is the application of rigorous statistical methods to earthquake science with the goal of improving our knowledge of how the earth works. Within statistical seismology there is a strong emphasis on the analysis of seismicity data in order to improve our scientific understanding of earthquakes and to improve the evaluation and testing of earthquake forecasts, earthquake early warning, and seismic hazards assessments. Given the societal importance of these applications, statistical seismology must be done well. Unfortunately, a lack of educational resources and available software tools make it difficult for students and new practitioners to learn about this discipline. The goal of the Community Online Resource for Statistical Seismicity Analysis (CORSSA) is to promote excellence in statistical seismology by providing the knowledge and resources necessary to understand and implement the best practices, so that the reader can apply these methods to their own research. This introduction describes the motivation for and vision of CORRSA. It also describes its structure and contents.

  18. Effect of irregularity on torsional surface waves in an initially ...

    Indian Academy of Sciences (India)

    initially stressed anisotropic porous layer sandwiched between ... layer under a rigid boundary and lying over an ..... surface is flat, the above boundary condition reduces to ..... Gubbins D 1990 Seismology and plate tectonics; Cambridge.

  19. Influence of yielding base and rigid base on propagation of Rayleigh ...

    Indian Academy of Sciences (India)

    S Saha

    2017-07-14

    Jul 14, 2017 ... seismology, geophysics, acoustics, telecommunication industries and material .... where / and w are the potential functions [26] of x, y and t. In view of Eq. (7), ...... buildings by self-centering systems using rocking mecha- nism.

  20. Final environmental statement: Pilgrim Nuclear Power Station, Unit No. 2. Final supplement. Docket No. 50-471

    International Nuclear Information System (INIS)

    1979-05-01

    Information on candidate sites is presented concerning aquatic biology and water quality; terrestrial ecology and land use; demography; nearby industrial, transportation, and military facilities; hydrology; socioeconomics; and geology, seismology, and geotechnical engineering

  1. Proceedings of the Conference on Structural Analysis and Design of Nuclear Power Plants. v. 2

    International Nuclear Information System (INIS)

    1984-01-01

    It's presented the discussion of recents research results and developments related to applications of structural mechanics and seismology to mechanical structures and to nuclear facility sites. (E.G.) [pt

  2. Seismics - Yesterday and today

    International Nuclear Information System (INIS)

    Frei, W.

    2014-01-01

    This article published in the Swiss Bulletin for Applied Geology takes a look at technical developments in the field of seismological exploration over the past 25 years. In particular, developments in the information technology area are discussed. Increased data-storage capacities and miniaturization of data-capture systems and sensors are examined. In spite of such developments, the quality of the seismological data acquired is quoted as not showing significantly increased quality. Alternatives to vibration-based seismic exploration are discussed. The challenges faced by near-surface seismology are looked at. Computer-based statistical correction of data and improved resolution are discussed, as is hybrid seismology. Examples are quoted and graphically illustrated. A list of relevant literature completes the article

  3. Zemětřesení ve službách energetiky

    Czech Academy of Sciences Publication Activity Database

    Šílený, Jan; Fischer, Tomáš

    2009-01-01

    Roč. 88, č. 12 (2009), s. 798-799 ISSN 0042-4544 Institutional research plan: CEZ:AV0Z30120515 Keywords : earthquake seismology * geothermal energy * seismic exploration Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  4. Seismologische Karten - ein Beispiel thematischer Kartographie

    Czech Academy of Sciences Publication Activity Database

    Kozák, Jan; Dušek, R.

    2003-01-01

    Roč. 27, - (2003), s. 27-35 ISSN 1015-8480 Institutional research plan: CEZ:AV0Z3012916 Keywords : seismological maps * earthquakes * volcanic eruptions Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  5. Frictional properties and slip stability of active faults within carbonate-evaporite sequences: The role of dolomite and anhydrite

    NARCIS (Netherlands)

    Scuderi, M.M.; Niemeijer, A.R.; Collettini, C.; Marone, C.

    2013-01-01

    Seismological observations show that many destructive earthquakes nucleate within, or propagate through, thick sequences of carbonates and evaporites. For example, along the Apennines range (Italy) carbonate and evaporite sequences are present at hypocentral depths for recent major earthquakes

  6. A numerical homogenization method for heterogeneous, anisotropic elastic media based on multiscale theory

    KAUST Repository

    Gao, Kai; Chung, Eric T.; Gibson, Richard L.; Fu, Shubin; Efendiev, Yalchin R.

    2015-01-01

    The development of reliable methods for upscaling fine-scale models of elastic media has long been an important topic for rock physics and applied seismology. Several effective medium theories have been developed to provide elastic parameters

  7. Asteroseismology of DAV White Dwarf Stars

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, Paul A.

    1997-12-31

    The author reviews the seismological structural determinations of ZZ Ceti stars done to date, and supplement these with additional preliminary determinations of his own. He compares the constraints on the hydrogen layer mass to see what trends emerge and also determines if the observed hydrogen layer masses are consistent with proposed theories. He then looks ahead to the prospects of further DAV white dwarf seismology.

  8. In Memoriam

    Science.gov (United States)

    Jorge Lomnitz-Adler died on December 17, 1993, at age 39. He had been a member of AGU (Seismology) since 1989. He was an associate editor of the Journal of Geophysical Research and a director of the Association of Seismology and Physics of the Earth's Interior. Weeks before his death, he was awarded the Prize for Young Academics from his institution, the National University of Mexico (UNAM). He was cited for his contributions to earthquake prediction, using avalanche and percolation models.

  9. Changes and challenges following the 1997 Colfiorito earthquake: the evolution of the use of the Internet for large seismic events

    Directory of Open Access Journals (Sweden)

    R. Camassi

    2008-06-01

    Full Text Available The September 26, 1997 Central Italy earthquake represents the first Italian large seismic event on the occasion of which Internet was intensively exploited to exchange and disseminate data, information and news. The paper illustrates how national and international seismological institutions disseminate information about earthquakes ten years ago. A web evolution is sketched, and some features that can be of interest today in the seismological community are presented.

  10. Isostatic Implications of Different Seismic and Gravity Derived Moho Depths for Antarctica

    Science.gov (United States)

    Ferraccioli, F.; Pappa, F.; Ebbing, J.

    2017-12-01

    Several studies with different methods have been performed to investigate the lithospheric structure of Antarctica, in particular the Moho as the crust-mantle boundary. Yet, seismological surveys are regionally limited or suffer from sparse station coverage due to the remoteness and size of the continent. On the other hand, gravity studies are inherently ambiguous and therefore not able to determine both the geometry and the density contrast of the Moho. Existing Moho depth models for Antarctica show large discrepancies, even among different seismological methods, but all the more between seismological and gravity models. As a first step towards a possible reconcilement, we perform non-linear gravity inversions with simultaneous consideration of seismological data. Depending on the seismological input data, different depths and density contrasts yield the best fit. The results, however, are not in line with the pure seismological models. Subsequently, we compute simple Airy-isostatic Moho depth models and evaluate these together with multiple Moho models from previous studies in terms of their gravitational signal, applying different values for the density contrast. The models' responses are checked against observational data: vertical gravity at 50 km altitude from the spherical harmonics expansion model GOCO05s, and the gravity gradient tensor at 225 km altitude from the GOCE gravity gradient grids. While the gravity responses from the seismological models show strong disagreements with the data, the Airy-isostatic models fit better. Yet, differences of up to 10 km in depth exist between the isostatic and the gravity-inverted Moho models. From these differences in vertical gravity, in the gravity gradients and in Moho depth, we identify regions where a simple density contrast is not sufficient to explain the observed gravitational field. We conclude that lateral and vertical density variations must be considered, which might originate from high-density lower

  11. Building the Community Online Resource for Statistical Seismicity Analysis (CORSSA)

    Science.gov (United States)

    Michael, A. J.; Wiemer, S.; Zechar, J. D.; Hardebeck, J. L.; Naylor, M.; Zhuang, J.; Steacy, S.; Corssa Executive Committee

    2010-12-01

    Statistical seismology is critical to the understanding of seismicity, the testing of proposed earthquake prediction and forecasting methods, and the assessment of seismic hazard. Unfortunately, despite its importance to seismology - especially to those aspects with great impact on public policy - statistical seismology is mostly ignored in the education of seismologists, and there is no central repository for the existing open-source software tools. To remedy these deficiencies, and with the broader goal to enhance the quality of statistical seismology research, we have begun building the Community Online Resource for Statistical Seismicity Analysis (CORSSA). CORSSA is a web-based educational platform that is authoritative, up-to-date, prominent, and user-friendly. We anticipate that the users of CORSSA will range from beginning graduate students to experienced researchers. More than 20 scientists from around the world met for a week in Zurich in May 2010 to kick-start the creation of CORSSA: the format and initial table of contents were defined; a governing structure was organized; and workshop participants began drafting articles. CORSSA materials are organized with respect to six themes, each containing between four and eight articles. The CORSSA web page, www.corssa.org, officially unveiled on September 6, 2010, debuts with an initial set of approximately 10 to 15 articles available online for viewing and commenting with additional articles to be added over the coming months. Each article will be peer-reviewed and will present a balanced discussion, including illustrative examples and code snippets. Topics in the initial set of articles will include: introductions to both CORSSA and statistical seismology, basic statistical tests and their role in seismology; understanding seismicity catalogs and their problems; basic techniques for modeling seismicity; and methods for testing earthquake predictability hypotheses. A special article will compare and review

  12. CORSSA: Community Online Resource for Statistical Seismicity Analysis

    Science.gov (United States)

    Zechar, J. D.; Hardebeck, J. L.; Michael, A. J.; Naylor, M.; Steacy, S.; Wiemer, S.; Zhuang, J.

    2011-12-01

    Statistical seismology is critical to the understanding of seismicity, the evaluation of proposed earthquake prediction and forecasting methods, and the assessment of seismic hazard. Unfortunately, despite its importance to seismology-especially to those aspects with great impact on public policy-statistical seismology is mostly ignored in the education of seismologists, and there is no central repository for the existing open-source software tools. To remedy these deficiencies, and with the broader goal to enhance the quality of statistical seismology research, we have begun building the Community Online Resource for Statistical Seismicity Analysis (CORSSA, www.corssa.org). We anticipate that the users of CORSSA will range from beginning graduate students to experienced researchers. More than 20 scientists from around the world met for a week in Zurich in May 2010 to kick-start the creation of CORSSA: the format and initial table of contents were defined; a governing structure was organized; and workshop participants began drafting articles. CORSSA materials are organized with respect to six themes, each will contain between four and eight articles. CORSSA now includes seven articles with an additional six in draft form along with forums for discussion, a glossary, and news about upcoming meetings, special issues, and recent papers. Each article is peer-reviewed and presents a balanced discussion, including illustrative examples and code snippets. Topics in the initial set of articles include: introductions to both CORSSA and statistical seismology, basic statistical tests and their role in seismology; understanding seismicity catalogs and their problems; basic techniques for modeling seismicity; and methods for testing earthquake predictability hypotheses. We have also begun curating a collection of statistical seismology software packages.

  13. Seismic imaging at the cross-roads: Active, passive, exploration and solid Earth

    Science.gov (United States)

    Rawlinson, N.; Stephenson, R.; Carbonell, R.

    2017-10-01

    Science has grown from our need to understand the world around us. Seismology is no different, with earthquakes and their destructive effect on society providing the motivation to understand the Earth's seismic wavefield. The question of when seismology as a science really began is an interesting one, but it is unlikely that there will ever be a universally agreed-upon date, partly because of the incompleteness of the historical record, and partly because the definition of what constitutes science varies from person to person. For instance, one could regard 1889 as the true birth of seismology, because that is when the first distant earthquake was detected by an instrument; in this case Ernst von Rebeur-Paschwitz detected an earthquake in Japan using a pendulum in Potsdam, Germany (Ben-Menahem, 1995). However, even the birth of instrumental seismology could be contested; the so-called Zhang Heng directional ;seismoscope; (detects ground motion but not as a function of time) was invented in 132 CE (Rui and Yan-xiang, 2006), and is said to have detected a four-hundred mile distant earthquake which was not felt at the location of the instrument (Needham, 1959; Dewey and Byerly, 1969). Prior to instrumental seismology, observations of earthquakes were not uncommon; for instance, Aristotle provided a classification of earthquakes based on the nature of observed ground motion (Ben-Menahem, 1995).

  14. Seismic Wave Propagation in Icy Ocean Worlds

    Science.gov (United States)

    Stähler, Simon C.; Panning, Mark P.; Vance, Steven D.; Lorenz, Ralph D.; van Driel, Martin; Nissen-Meyer, Tarje; Kedar, Sharon

    2018-01-01

    Seismology was developed on Earth and shaped our model of the Earth's interior over the twentieth century. With the exception of the Philae lander, all in situ extraterrestrial seismological effort to date was limited to other terrestrial planets. All have in common a rigid crust above a solid mantle. The coming years may see the installation of seismometers on Europa, Titan, and Enceladus, so it is necessary to adapt seismological concepts to the setting of worlds with global oceans covered in ice. Here we use waveform analyses to identify and classify wave types, developing a lexicon for icy ocean world seismology intended to be useful to both seismologists and planetary scientists. We use results from spectral-element simulations of broadband seismic wavefields to adapt seismological concepts to icy ocean worlds. We present a concise naming scheme for seismic waves and an overview of the features of the seismic wavefield on Europa, Titan, Ganymede, and Enceladus. In close connection with geophysical interior models, we analyze simulated seismic measurements of Europa and Titan that might be used to constrain geochemical parameters governing the habitability of a sub-ice ocean.

  15. Botswana's perspectives on CTBTO related regional cooperation in Africa

    International Nuclear Information System (INIS)

    Holmes, H.

    2002-01-01

    The CTBTO vertification technology most attractive to Botswana is seismological observation. This is so even though, by global standards, the seismic activity of Botswana is very low. The Okavango Delta, Botswana's most active region, has an annual activity rate of about 2 tremors of magnitude <4. This is an alost insignificant number considering that worldwide, thousands of earthquakes of magnitude 1 occur daily. This low activity rate has resulted in a lack of urgency in making concerted efforts to put in place systems for national monitoring of earthquakes. This has adversely affected the transfer of expertise and technology to Botswana, and has resulted in very limited documentation of the country's seismicity. Recently, however, there have been some developments that are bound to change the situation and improve the country's capabilities in seismological observation. The Department of Geological Survey (DGS) is involved in international cooperation as well as national projects that will undoubtedly enhance the practice of seismology in Botswana

  16. The BRAzilian Seismographic Integrated Systems (BRASIS: infrastructure and data management

    Directory of Open Access Journals (Sweden)

    João Carlos Dourado

    2011-04-01

    Full Text Available In geophysics and seismology, raw data need to be processed to generate useful information that can be turned into knowledge by researchers. The number of sensors that are acquiring raw data is increasing rapidly. Without good data management systems, more time can be spent in querying and preparing datasets for analyses than in acquiring raw data. Also, a lot of good quality data acquired at great effort can be lost forever if they are not correctly stored. Local and international cooperation will probably be reduced, and a lot of data will never become scientific knowledge. For this reason, the Seismological Laboratory of the Institute of Astronomy, Geophysics and Atmospheric Sciences at the University of São Paulo (IAG-USP has concentrated fully on its data management system. This report describes the efforts of the IAG-USP to set up a seismology data management system to facilitate local and international cooperation.

  17. Tectonic stability and expected ground motion at Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1984-10-02

    A workshop was convened on August 7-8, 1984 at the direction of DOE to discuss effects of natural and artificial earthquakes and associated ground motion as related to siting of a high-level radioactive waste (HLW) repository at Yucca Mountain, Nevada. A panel of experts in seismology and tectonics was assembled to review available data and analyses and to assess conflicting opinions on geological and seismologic data. The objective of the meeting was to advise the Nevada Nuclear Waste Storage Investigations (NNWSI) Project about how to present a technically balanced and scientifically credible evaluation of Yucca Mountain for the NNWSI Project EA. The group considered two central issues: the magnitude of ground motion at Yucca Mountain due to the largest expected earthquake, and the overall tectonic stability of the site given the current geologic and seismologic data base. 44 refs.

  18. Tectonic stability and expected ground motion at Yucca Mountain

    International Nuclear Information System (INIS)

    1984-01-01

    A workshop was convened on August 7-8, 1984 at the direction of DOE to discuss effects of natural and artificial earthquakes and associated ground motion as related to siting of a high-level radioactive waste (HLW) repository at Yucca Mountain, Nevada. A panel of experts in seismology and tectonics was assembled to review available data and analyses and to assess conflicting opinions on geological and seismologic data. The objective of the meeting was to advise the Nevada Nuclear Waste Storage Investigations (NNWSI) Project about how to present a technically balanced and scientifically credible evaluation of Yucca Mountain for the NNWSI Project EA. The group considered two central issues: the magnitude of ground motion at Yucca Mountain due to the largest expected earthquake, and the overall tectonic stability of the site given the current geologic and seismologic data base. 44 refs

  19. Determining the stress field in active volcanoes using focal mechanisms

    Directory of Open Access Journals (Sweden)

    Bruno Massa

    2016-11-01

    Full Text Available Stress inversion of seismological datasets became an essential tool to retrieve the stress field of active tectonics and volcanic areas. In particular, in volcanic areas, it is able to put constrains on volcano-tectonics and in general in a better understanding of the volcano dynamics. During the last decades, a wide range of stress inversion techniques has been proposed, some of them specifically conceived to manage seismological datasets. A modern technique of stress inversion, the BRTM, has been applied to seismological datasets available at three different regions of active volcanism: Mt. Somma-Vesuvius (197 Fault Plane Solutions, FPSs, Campi Flegrei (217 FPSs and Long Valley Caldera (38,000 FPSs. The key role of stress inversion techniques in the analysis of the volcano dynamics has been critically discussed. A particular emphasis was devoted to performances of the BRTM applied to volcanic areas.

  20. On the EMSC and its roles in the Euro-Med region

    Science.gov (United States)

    Bossu, R.; Godey, S.; Mazet-Roux, G.

    2009-04-01

    The Euro-Med seismological Centre (EMSC) is a scientific non-profit NGO created back in 1975 by the seismological community to collate data, make them available and provide earthquake information at a Euro-Med and global scales. The aim of this talk is to provide an overview of the EMSC's activities and its roles in the integration of the seismological community. Its first activity has been rapid earthquake information on its web site (www.emsc-csem.org) as well as earthquake notification services (SMS, email) for potentially damaging earthquakes. More recently, online macroseismic questionnaires were introduced in more than 20 different languages as well as tools to collect pictures of the earthquake's effects from the public. An innovative way to map the area where an earthquake was felt within 5 to 8 minutes of its occurrence was developed. It plots the geographical origin of the observed surges of traffic following felt events. This method is now being implemented in several other institutes. The Euro-Med seismological bulletin, which started in 1998, complements this service by offering a reference bulletin for the region. It significantly improved the data availability especially on the fringes of the region and the data collection is now comprehensive. Thanks to its 84 institutes from 55 different countries, EMSC offers a significant networking capacity and it plays a significant role in the integration of our community in close collaboration with ORFEUS, the second European organisation in seismology. It devotes significant efforts to improve collaboration especially towards Northern Africa and the Middle East. For example, it recently led an EC-project to improve coordination of the earthquake surveillance of the Western Mediterranean region and improve data exchanges. It contributes to the initiation of the NERIES project. It is involved, within this framework, in improving accelerometric data availability, developing rapid loss estimates and it it is in

  1. History of endeavours to mitigate the rockburst risk in South African mines

    CSIR Research Space (South Africa)

    Durrheim, RJ

    2012-04-01

    Full Text Available for periods of a few months to a few years. ?Golden decade? of mine seismology at BPI Geophysics (1969-1979) From 1969 to 1979 the BPI Geophysics team of Art McGarr, Steve Spottiswoode, Rod Green and Nick Gay contributed significantly to the emerging... discipline of mine seismology (e.g. McGarr 1971; Spottiswoode and McGarr 1975; McGarr et al. 1975; Gay and Ortlepp 1979 and McGarr et al. 1981). Much of this work was carried out at ERPM. The magnitudes of the stresses driving violent failure...

  2. Memorial - Fritz Matthiesen (1926-1981)

    OpenAIRE

    Jennings, Paul C.

    1982-01-01

    R. B. "Fritz" Matthiesen died on 26 October 1981, at the age of 54, a victim of cancer, and his untimely death was a sad loss to his colleagues in earthquake engineering and seismology. We all miss his technical abilities, his sharp wit, and his irreverent ways of dealing with bureaucracy. Fritz had long been active in the affairs of the Seismological Society of America and was on the Board of Directors at the time of his death. His special technical interests were in the measu...

  3. Solar and stellar oscillations

    International Nuclear Information System (INIS)

    Fossat, E.

    1981-01-01

    We try to explain in simple words what a stellar oscillation is, what kind of restoring forces and excitation mechanisms can be responsible for its occurence, what kind of questions the theoretician asks to the observer and what kind of tools the latter is using to look for the answers. A selected review of the most striking results obtained in the last few years in solar seismology and the present status of their consequences on solar models is presented. A brief discussion on the expected extension towards stellar seismology will end the paper. A selected bibliography on theory as well as observations and recent papers is also included. (orig.)

  4. Activity report 1990-1992 and proceedings. Volume I

    International Nuclear Information System (INIS)

    Mayer-Rosa, D.; Waniek, L.; Suhadolc, P.

    1993-01-01

    A report on the activities of the European Seismological Commission (ESC) during the period 1990-1992 together with the Proceedings of the General Assembly of theESC are presented in two volumes. Volume I covers the following topics: recent strong earthquakes in Europe, regional seismicity, historical earthquakes in Europe, statistical models and methods in seismology, numerical modelling in three-dimensional media, methodology of quantification of European earthquakes and recent results, seismic noise and signal detectability, regional seismic network and history of seismometry. One paper dealing with microseismic noise characteristics around the Kozloduy nuclear power plant has been inputted to INIS. (Z.S.)

  5. Fundamental aspects of seismic event detection, magnitude estimation and their interrelation

    International Nuclear Information System (INIS)

    Ringdal, F.

    1977-01-01

    The main common subject of the papers forming this thesis is statistical model development within the seismological disciplines of seismic event detection and event magnitude estimation. As more high quality seismic data become available as a result of recent seismic network developments, the opportunity will exist for large scale application and further refinement of these models. It is hoped that the work presented here will facilitate improved understanding of the basic issues, both within earthquake-explosion discrimination, in the framework of which most of this work originated, and in seismology in general. (Auth.)

  6. Determination of S-wave slowness from a linear array of borehole receivers

    Czech Academy of Sciences Publication Activity Database

    Eisner, L.; Fischer, Tomáš; Rutledge, J. T.

    2009-01-01

    Roč. 176, č. 1 (2009), s. 31-39 ISSN 0956-540X Grant - others:EC(XE) MTKI-CT-2004-517242 Institutional research plan: CEZ:AV0Z30120515 Keywords : downhole methods * controlled source seismology * body waves * wave propagation Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.435, year: 2009

  7. Complex researches on substantiation of construction and seismic stability of large dams in seismic region

    International Nuclear Information System (INIS)

    Negmatullaev, S.Kh.; Yasunov, P.A.

    2001-01-01

    This article is devoted to complex researches on substantiation of construction and seismic stability of large dams (Nurec hydroelectric power station) in seismic region. Geological, seismological, model, and engineering investigations are discussed in this work. At construction of Nurec hydroelectric power station the rich experience is accumulated. This experience can be used in analogous seismically active regions at construction similar hydroelectric power stations.

  8. Recent solution of the distributed control and measurement system in the Jeronym Mine - modular system

    Czech Academy of Sciences Publication Activity Database

    Knejzlík, Jaromír; Rambouský, Zdeněk

    2008-01-01

    Roč. 5, č. 2 (2008), s. 205-212 ISSN 1214-9705 R&D Projects: GA ČR GA105/06/0068 Institutional research plan: CEZ:AV0Z30860518 Keywords : Jeronym Mine * geomechanical monitoring * seismological monitoring Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  9. RUP2004 - High definition apparatus for Standalone, network and micro-array applications in seismic

    Czech Academy of Sciences Publication Activity Database

    Štrunc, Jaroslav; Brož, Milan

    2006-01-01

    Roč. 6, č. 2 (2006), s. 281-283 ISSN 1213-1962 R&D Projects: GA ČR(CZ) GD205/05/H020 Institutional research plan: CEZ:AV0Z30460519 Keywords : seismology * GPS * GSM Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  10. Israel Geological Society, annual meeting 1994

    International Nuclear Information System (INIS)

    Amit, R.; Arkin, Y.; Hirsch, F.

    1994-02-01

    The document is a compilation of papers presented during the annual meeting of Israel Geological Society. The document is related with geological and environmental survey of Israel. It discusses the technology and instruments used to carry out such studies. Main emphasis is given to seismology, geochemical analysis of water, water pollution and geophysical survey of rocks

  11. Source mechanisms of mining-related seismic events in the Far West Rand, South Africa

    CSIR Research Space (South Africa)

    Kassa, BB

    2009-09-01

    Full Text Available . International Handbook of Earthquake and Engineering Seismology, ed. W. H. K. Lee, H. Kanamori, P. C. Jennings, and C. Kisslinger, chapter 85.12. San Diego: Academic Press. Trifu, C-I., Angus, D. and Shumila, V. (2000). A fast evaluation of the seismic...

  12. The female scientist who discovered the core of the Earth

    DEFF Research Database (Denmark)

    Lund Jacobsen, A. Lif

    2017-01-01

    The "Grande Dame” of seismology, Inge Lehmann, began her career at a time when few women held senior positions in science. But that did not stop her from being the first to provide evidence of the Earth’s inner core in 1936....

  13. Geofyzikální modely svahových deformací

    Czech Academy of Sciences Publication Activity Database

    Bláha, P.; Müller, Karel

    2004-01-01

    Roč. 4, č. 2 (2004), s. 39-47 ISSN 1213-1962. [ Development of seismology, engineering geophysics and geotechnique/13./. Ostrava, 30.03.2004-01.04.2004] Institutional research plan: CEZ:AV0Z3086906 Keywords : geophysics * slope deformations Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  14. The vibration of a layered rotating planet and Bryan’s effect

    CSIR Research Space (South Africa)

    Shatalov, MY

    2011-12-01

    Full Text Available As among other seismological observations, it is important to be able to predict the location of the vibrating pattern of an earthquake. In this chapter, the authors take the first tentative steps towards including "Bryan’s effect" in a mathematical...

  15. Estimation of earthquake source parameters in the Kachchh seismic ...

    Indian Academy of Sciences (India)

    SEISAN software has been used to locate the identified local earthquakes, which were recorded at least three or more stations of the Kachchh seismological network. Three component spectra of S-wave are being inverted by using the Levenberg–Marquardt non-linear inversion technique, wherein the inversion scheme is ...

  16. Effects of relative plate motion on the deep structure and penetration depth of slabs below the Izu-Bonin and Mariana island arcs

    NARCIS (Netherlands)

    Hilst, R.D. van der; Seno, Tetsuzo

    1993-01-01

    An increasing number of seismological studies indicate that slabs of subducted lithosphere penetrate the Earth's lower mantle below some island arcs but are deflected, or, rather, laid down, in the transition zone below others. Recent numerical simulations of mantle flow also advocate a hybrid form

  17. The subduction structure of the Northern Apennines: results from the RETREAT seismic deployment

    Czech Academy of Sciences Publication Activity Database

    Margheriti, L.; Pondrelli, S.; Piccinini, D.; Agostineti, N. P.; Giovani, L.; Salimbeni, S.; Lucente, F. P.; Amato, A.; Baccheschi, P.; Park, J.; Brandon, M.; Levin, V.; Plomerová, Jaroslava; Jedlička, Petr; Vecsey, Luděk; Babuška, Vladislav; Fiaschi, A.; Carpani, B.; Ulbricht, P.

    2006-01-01

    Roč. 49, č. 4-5 (2006), s. 1119-1131 ISSN 1593-5213 R&D Projects: GA AV ČR IAA3012405 Institutional research plan: CEZ:AV0Z30120515 Keywords : temporary seismological network * subduction geometry * upper mantle fabric * seismic anisotropy Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.441, year: 2006

  18. Geophysical Institute. Biennial report, 1993-1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-01-01

    The 1993-1994 Geophysical Institute Biennial Report was published in November 1995 by the Geophysical Institute of the University of Alaska Fairbanks. It contains an overview of the Geophysical Institute, the Director`s Note, and research presentations concerning the following subjects: Scientific Predictions, Space Physics, Atmospheric Sciences, Snow, Ice and Permafrost, Tectonics and Sedimentation, Seismology, Volcanology, Remote Sensing, and other projects.

  19. Seismic monitoring: a unified system for research and verifications

    International Nuclear Information System (INIS)

    Thigpen, L.

    1979-01-01

    A system for characterizing either a seismic source or geologic media from observational data was developed. This resulted from an examination of the forward and inverse problems of seismology. The system integrates many seismic monitoring research efforts into a single computational capability. Its main advantage is that it unifies computational and research efforts in seismic monitoring. 173 references, 9 figures, 3 tables

  20. Complex rupture mechanism and topography control symmetry of mass - wasting pattern, 2010 Haiti earthquake

    NARCIS (Netherlands)

    Gorum, T.; van Westen, C.J.; Korup, Oliver; van der Meijde, M.; Fan, Xuanmei; van der Meer, F.D.

    2013-01-01

    The 12 January 2010 Mw 7.0 Haiti earthquake occurred in a complex deformation zone at the boundary between the North American and Caribbean plates. Combined geodetic, geological and seismological data posited that surface deformation was driven by rupture on the Léogâne blind thrust fault, while

  1. Elementary Green function as an integral superposition of Gaussian beams in inhomogeneous anisotropic layered structures in Cartesian coordinates

    Czech Academy of Sciences Publication Activity Database

    Červený, V.; Pšenčík, Ivan

    2017-01-01

    Roč. 210, č. 2 (2017), s. 561-569 ISSN 0956-540X R&D Projects: GA ČR(CZ) GA16-05237S Institutional support: RVO:67985530 Keywords : body waves * seismic anisotropy * theoretical seismology * wave propagation Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 2.414, year: 2016

  2. The data quality analyzer: a quality control program for seismic data

    Science.gov (United States)

    Ringler, Adam; Hagerty, M.T.; Holland, James F.; Gonzales, A.; Gee, Lind S.; Edwards, J.D.; Wilson, David; Baker, Adam

    2015-01-01

    The U.S. Geological Survey's Albuquerque Seismological Laboratory (ASL) has several initiatives underway to enhance and track the quality of data produced from ASL seismic stations and to improve communication about data problems to the user community. The Data Quality Analyzer (DQA) is one such development and is designed to characterize seismic station data quality in a quantitative and automated manner.

  3. Determination and uncertainty of moment tensors for microearthquakes at Okmok Volcano, Alaska

    Czech Academy of Sciences Publication Activity Database

    Pesicek, J. D.; Šílený, Jan; Prejean, S. G.; Thurber, C. H.

    2012-01-01

    Roč. 190, č. 3 (2012), s. 1689-1709 ISSN 0956-540X R&D Projects: GA ČR GAP210/12/2235 Institutional research plan: CEZ:AV0Z30120515 Keywords : earthquake source observations * volcano seismology * body waves Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.853, year: 2012

  4. Body-wave seismic interferometry applied to earthquake- and storm-induced wavefield

    NARCIS (Netherlands)

    Ruigrok, E.N.

    2012-01-01

    Seismology is the study of the vibration of the Earth. Seismologists pay much attention to the main source of Earth vibration: earthquakes. But also other seismic sources, like mining blasts, ocean storms and windmills, are studied. All these sources induce seismic waves, which can eventually be

  5. New portable sensor system for rotation seismic motion measurements

    Czech Academy of Sciences Publication Activity Database

    Brokešová, J.; Málek, Jiří

    2010-01-01

    Roč. 81, č. 8 (2010), 084501 ISSN 0034-6748 R&D Projects: GA ČR GAP210/10/0925 Institutional research plan: CEZ:AV0Z30460519 Keywords : rotation al seismology * sensor system Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.598, year: 2010

  6. Hanford site environment

    International Nuclear Information System (INIS)

    Isaacson, R.E.

    1976-01-01

    A synopsis is given of the detailed characterization of the existing environment at Hanford. The following aspects are covered: demography, land use, meteorology, geology, hydrology, and seismology. It is concluded that Hanford is one of the most extensively characterized nuclear sites

  7. Shaking table qualification tests of mechanical and electrical components

    International Nuclear Information System (INIS)

    Jurukovski, D.

    1993-01-01

    This presentation covers the experience of the Institute of Earthquake Engineering and Engineering Seismology, Skopje, Republic of Macedonia in seismic qualification of mechanical components by shaking table testing. The characteristics of the biaxial seismic and single component shaking tables used at the Institute are given. Some examples of the experience from performed test for reactor components are included

  8. Solving or resolving inadequate and noisy tomographic systems

    NARCIS (Netherlands)

    Nolet, G.

    1985-01-01

    Tomography in seismology often leads to underdetermined and inconsistent systems of linear equations. When solving, care must be taken to keep the propagation of data errors under control. In this paper I test the applicability of three types of damped least-squares algorithms to the kind of

  9. Hanford site as it relates to an alternative site for the Waste Isolation Pilot Plant: an environmental description

    Energy Technology Data Exchange (ETDEWEB)

    Fecht, K.R. (ed.)

    1978-12-01

    The use of basalt at Hanford as an alternative for the Waste Isolation Pilot Plant (WIPP) would require that the present Basalt Waste Isolation Program (BWIP) at Hanford be expanded to incorporate the planned WIPP functions, namely the permanent storage of transuranic (TRU) wastes. This report discusses: program costs, demography, ecology, climatology, physiography, hydrology, geology, seismology, and historical and archeological sites. (DLC)

  10. Rotaphone, a Self-Calibrated Six-Degree-of-Freedom Seismic Sensor and Its Strong-Motion Records

    Czech Academy of Sciences Publication Activity Database

    Brokešová, J.; Málek, Jiří

    2013-01-01

    Roč. 84, č. 5 (2013), s. 737-744 ISSN 0895-0695 R&D Projects: GA ČR GAP210/10/0925; GA MŠk LM2010008 Institutional support: RVO:67985891 Keywords : rotational seismology * sensor * six-degree-of-freedom Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.268, year: 2013

  11. Characterization and application of microearthquake clusters to problems of scaling, fault zone dynamics, and seismic monitoring at Parkfield, California

    Energy Technology Data Exchange (ETDEWEB)

    Nadeau, Robert Michael [Univ. of California, Berkeley, CA (United States)

    1995-10-01

    This document contains information about the characterization and application of microearthquake clusters and fault zone dynamics. Topics discussed include: Seismological studies; fault-zone dynamics; periodic recurrence; scaling of microearthquakes to large earthquakes; implications of fault mechanics and seismic hazards; and wave propagation and temporal changes.

  12. Hypocentre estimation of induced earthquakes in Groningen

    NARCIS (Netherlands)

    Spetzler, J.; Dost, Bernard

    2017-01-01

    Induced earthquakes due to gas production have taken place in the province of Groningen in the northeast of The Netherlands since 1986. In the first years of seismicity, a sparse seismological network with large station distances from the seismogenic area in Groningen was used. The location of

  13. Application of the Region-Time-Length algorithm to study of ...

    Indian Academy of Sciences (India)

    51

    analyzed using the Region-Time-Length (RTL) algorithm based statistical technique. The utilized earthquake data were obtained from the International Seismological Centre. Thereafter, the homogeneity and completeness of the catalogue were improved. After performing iterative tests with different values of the r0 and t0 ...

  14. Developments in new fluid rotational seismometers: instrument performance and future directions

    Czech Academy of Sciences Publication Activity Database

    Evans, J. R.; Kozák, Jan; Jedlička, Petr; Jedlička, Z.

    2016-01-01

    Roč. 106, č. 6 (2016), s. 2865-2876 ISSN 0037-1106 R&D Projects: GA MŠk(CZ) ME10008 Institutional support: RVO:67985530 Keywords : ground motions * sensors * seismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.146, year: 2016

  15. Hanford site as it relates to an alternative site for the Waste Isolation Pilot Plant: an environmental description

    International Nuclear Information System (INIS)

    Fecht, K.R.

    1978-12-01

    The use of basalt at Hanford as an alternative for the Waste Isolation Pilot Plant (WIPP) would require that the present Basalt Waste Isolation Program (BWIP) at Hanford be expanded to incorporate the planned WIPP functions, namely the permanent storage of transuranic (TRU) wastes. This report discusses: program costs, demography, ecology, climatology, physiography, hydrology, geology, seismology, and historical and archeological sites

  16. Earth Sciences Division annual report, 1976

    International Nuclear Information System (INIS)

    Hornady, B.; Duba, A.

    1977-01-01

    This compilation lists abstracts of papers, internal reports, and talks presented during 1976 at national and international meetings by members of the Earth Sciences Division, Lawrence Livermore Laboratory. Subjects include: coal gasification, gas stimulation, geothermal fields, oil shale retorting, radioactive waste management, geochemistry, geophysics, seismology, explosive phenomenology, and miscellaneous studies

  17. Big Data analytics in the Geo-Spatial Domain

    NARCIS (Netherlands)

    R.A. Goncalves (Romulo); M.G. Ivanova (Milena); M.L. Kersten (Martin); H. Scholten; S. Zlatanova; F. Alvanaki (Foteini); P. Nourian (Pirouz); E. Dias

    2014-01-01

    htmlabstractBig data collections in many scientific domains have inherently rich spatial and geo-spatial features. Spatial location is among the core aspects of data in Earth observation sciences, astronomy, and seismology to name a few. The goal of our project is to design an efficient data

  18. Asteroseismology of Scuti Stars

    Indian Academy of Sciences (India)

    Abstract. We briefly outline the state-of-the-art seismology of Scuti stars from a theoretical point of view: why is it so difficult a task? The recent theoretical advances in the field that these difficulties have influenced are also discussed.

  19. International cooperation in the field of studying seismic resistance of NPP components

    International Nuclear Information System (INIS)

    Kaznovskij, S.P.; Chechenov, Kh.D.

    1989-01-01

    Main results of the conference of representations from the USSR, Bulgarie, Hungary and Chechoslovakia related to the problems of seismology and seismic resistance of NPPs are briefly formulated. One of the important results of the conference consists in the agrement concerning cooperation and mutual application of seismoexplosive testing ground near Nalchik

  20. Environmental statement for Applications Technology Satellite program

    Science.gov (United States)

    1971-01-01

    The experiments, environmental impact, and applications of data collected by ATS are discussed. Data cover communications, navigation, meteorology, data collection (including data from small unattended remote stations such as buoys, seismology and hydrology monitors, etc.), geodesy, and scientific experiments to define the environment at synchronous orbit, and to monitor emissions from the sun.

  1. Cross-correlation—an objective tool to indicate induced seismicity

    Czech Academy of Sciences Publication Activity Database

    Opršal, I.; Eisner, Leo

    2014-01-01

    Roč. 196, č. 3 (2014), s. 1536-1543 ISSN 0956-540X Institutional support: RVO:67985891 Keywords : time series analysis * earthquake interaction * forecasting and prediction * statistical seismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.724, year: 2013

  2. Sequential Analysis: Hypothesis Testing and Changepoint Detection

    Science.gov (United States)

    2014-07-11

    maintains the flexibility of deciding sooner than the fixed sample size procedure at the price of some lower power [13, 514]. The sequential probability... markets , detection of signals with unknown arrival time in seismology, navigation, radar and sonar signal processing, speech segmentation, and the... skimming cruise missile can yield a significant increase in the probability of raid annihilation. Furthermore, usually detection systems are

  3. Journal of Astrophysics and Astronomy | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We give an overview of past and present efforts to make seismology of Scuti and Doradus stars possible. Previous work has not led to the observational detection and identification of a sufficient number of pulsation modes for these pulsators for the construction of unique seismic models. However ...

  4. A framework for fast probabilistic centroid-moment-tensor determination-inversion of regional static displacement measurements

    NARCIS (Netherlands)

    Käufl, P.J.; Valentine, A.P.; O'Toole, T.B.; Trampert, J.

    2014-01-01

    The determination of earthquake source parameters is an important task in seismology. For many applications, it is also valuable to understand the uncertainties associated with these determinations, and this is particularly true in the context of earthquake early warning (EEW) and hazard mitigation.

  5. Seizmická odezva trhací práce na ražených tunelech stavby 514 Lahovice - Slivenec

    Czech Academy of Sciences Publication Activity Database

    Stolárik, Martin

    2010-01-01

    Roč. 17, č. 1 (2010), s. 45-55 ISSN 1803-1447 R&D Projects: GA ČR GA105/09/1415 Institutional research plan: CEZ:AV0Z30860518 Keywords : seismological measurements * sensor seating * wave patterns * amplitude domains * frequency domains Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  6. First results of cross-correlation analysis of ambient seismic noise from the Hellenic Unified Seismic Network

    NARCIS (Netherlands)

    Panou, Areti; Paulssen, Hanneke; Hatzidimitriou, Panagiotis

    2015-01-01

    In this study we present phase velocity maps that were obtained from the cross-correlation analysis of ambient seismic noise recorded in the region of Greece.We used one year (2013) of ambient seismic data obtained from the vertical component of 64 broadband permanent seismological stations that are

  7. From field geology to earthquake simulation: A new state-of-The-art tool to investigate rock friction during the seismic cycle (SHIVA)

    NARCIS (Netherlands)

    Di Toro, G.; Niemeijer, A.; Tripoli, A.; Nielsen, S.; Di Felice, F.; Scarlato, P.G.; Spada, G.; Romeo, G.; Di Stefano, G.; Smith, S.; Mariano, S.

    2009-01-01

    Despite considerable effort over the past several decades, the mechanics of earthquake rupture remains largely unknown. Moderate- to large-magnitude earthquakes nucleate at 7–15 km depth and most information is retrieved from seismology, but information related to the physico-chemical processes

  8. From field geology to earthquake simulation: A new state-of-The-art tool to investigate rock friction during the seismic cycle (SHIVA)

    NARCIS (Netherlands)

    di Toro, Giulio; Niemeijer, André|info:eu-repo/dai/nl/370832132; Tripoli, Antonino; Nielsen, Stefan; Di Felice, Fabio; Scarlato, Piergiorgio; Spada, Giuseppe; Allesandroni, Roberto; Romeo, Giovanni; di Stefano, Giuseppe; Smith, Steven; Spagnuolo, Elena; Mariano, Sofia

    2010-01-01

    Despite considerable effort over the past several decades, the mechanics of earthquake rupture remains largely unknown. Moderate- to large-magnitude earthquakes nucleate at 7–15 km depth and most information is retrieved from seismology, but information related to the physico-chemical processes

  9. Geophysical observations and prediction of geophysical fields for users

    Czech Academy of Sciences Publication Activity Database

    Bochníček, Josef; Laštovička, Jan; Schenk, Vladimír; Boška, Josef; Burešová, Dalia; Hejda, Pavel; Horáček, Josef; Kottnauer, Pavel; Križan, Peter; Nejedlá, Jaroslava; Růžek, Bohuslav; Schenková, Zdeňka; Šauli, Petra; Zedník, Jan

    -, č. 14 (2005), s. 51-59 ISSN 1214-9691 R&D Projects: GA AV ČR IBS3012007 Institutional research plan: CEZ:AV0Z30120515 Keywords : geomagnetism * ionosphere * seismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  10. Research and development activities of the High Pressure Physics Division for the period March 1991-September 1993

    International Nuclear Information System (INIS)

    Godwal, B.K.; Bhadauria, Y.S.

    1993-01-01

    The research and development activities of the High Pressure Physics Division during the period March 1991 to September 1993 are reported in the form of abstracts and titles of the publications. The report is organised into two sections: (A) High Pressure Physics Section, and (B) Seismology Section. A list of staff members of the two sections is also given. (author)

  11. Research and development activities of the Neutron Physics Division for the period January 1977-December 1978

    International Nuclear Information System (INIS)

    Ramanadham, M.; Joneja, O.P.

    1979-01-01

    The research and development programmes of the Neutron Physics Division of the Bhabha Atomic Research Centre, Bombay, for the period 1977-1978 are outlined. The fields covered include reactor (neutron) physics, fusion and plasma neutronics, biological and high precision crystallography, solid state phenomena and seismology as well as the associated workshop facilities. (K.B.)

  12. Earthquake clustering in the tectonic pattern and volcanism of the Andaman Sea region

    Czech Academy of Sciences Publication Activity Database

    Špičák, Aleš; Vaněk, Jiří

    2013-01-01

    Roč. 608, November (2013), s. 728-736 ISSN 0040-1951 R&D Projects: GA MŠk ME09011 Institutional support: RVO:67985530 Keywords : earthquake swarm * Andaman Sea region * global seismological data * submarine volcanism * magma intrusion Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.866, year: 2013

  13. Seismically active column and volcanic plumbing system beneath the island arc of the Izu-Bonin subduction zone

    Czech Academy of Sciences Publication Activity Database

    Špičák, Aleš; Vaněk, Jiří; Hanuš, Václav

    2009-01-01

    Roč. 179, č. 3 (2009), s. 1301-1312 ISSN 0956-540X Institutional research plan: CEZ:AV0Z30120515 Keywords : seismicity and tectonics * volcano seismology * subduction zone processes * volcanic arc processes * magma migration and fragmentation * Pacific Ocean Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.435, year: 2009

  14. The theory of elastic waves and waveguides

    CERN Document Server

    Miklowitz, J

    1984-01-01

    The primary objective of this book is to give the reader a basic understanding of waves and their propagation in a linear elastic continuum. The studies of elastodynamic theory and its application to fundamental value problems should prepare the reader to tackle many physical problems of general interest in engineering and geophysics, and of particular interest in mechanics and seismology.

  15. GIS Navigation Boosted by Column Stores

    NARCIS (Netherlands)

    Alvanaki, F.; Goncalves, R.; Ivanova, M.; Kersten, M.; Kyzirakos, K.

    2015-01-01

    Earth observation sciences, astronomy, and seismology have large data sets which have inherently rich spatial and geospatial information. In combination with large collections of semantically rich objects which have a large number of thematic properties, they form a new source of knowledge for urban

  16. 78 FR 26399 - National Science Board; Sunshine Act Meetings; Notice

    Science.gov (United States)

    2013-05-06

    ... business and other matters specified, as follows: AGENCY HOLDING MEETING: National Science Board. DATE AND... (LIGO) renewal proposal Information Item: Advanced Technology Solar Telescope (ATST) Committee on... Geosciences and EarthScope (GAGE) and Seismological Facilities for the Advancement of Geoscience and Earth...

  17. West Valley Reprocessing Plant. Safety analysis plant, supplement 18

    International Nuclear Information System (INIS)

    1975-01-01

    Supplement 18 contains the following additions to Appendix II--5.0 Geology and Seismology: Section 12 ''Seismic Investigations for Spent Fuel Reprocessing Facility at West Valley, New York,'' October 20, 1975, and Section 13 ''Earthquake Return Period Analysis at West Valley, New York, for Nuclear Fuel Services, Inc.'' November 5, 1975

  18. 78 FR 59731 - License Amendment Request for Closure of Calcium Fluoride Ponds at Honeywell Metropolis Works...

    Science.gov (United States)

    2013-09-27

    ... Closure of Calcium Fluoride Ponds at Honeywell Metropolis Works, Honeywell International, Inc. AGENCY... Federal Regulations (10 CFR) to approve the closure of the calcium fluoride ponds in-place, by... areas: Land use; transportation; geology, soils and seismology; hydrology; ecological resources; air...

  19. 77 FR 11111 - Assessment of Potential Large-Scale Mining on the Bristol Bay Watershed of Alaska: Nomination of...

    Science.gov (United States)

    2012-02-24

    ... effects are likely to affect wildlife and human populations in the region. Additional information..., (6) seismology, (7) ecotoxicology, (8) wildlife ecology, and/or (9) indigenous Alaskan cultures... committee setting; (4) absence of financial conflicts of interest; (5) no actual conflicts of interest or...

  20. Fine scale heterogeneity in the Earth's upper mantle - observation and interpretation

    DEFF Research Database (Denmark)

    Thybo, Hans

    2014-01-01

    can be correlated to main plate tectonic features, such as oceanic spreading centres, continental rift zones and subducting slabs. Much seismological mantle research is now concentrated on imaging fine scale heterogeneity, which may be detected and imaged with high-resolution seismic data with dense...

  1. Constraining P-wave velocity variations in the upper mantle beneath Southeast Asia

    NARCIS (Netherlands)

    Li, Chang; Hilst, R.D. van der; Toksöz, M. Nafi

    2006-01-01

    We have produced a P-wave model of the upper mantle beneath Southeast (SE) Asia from reprocessed short period International Seismological Centre (ISC) P and pP data, short period P data of the Annual Bulletin of Chinese Earthquakes (ABCE), and long period PP-P data.We used 3D sensitivity kernels

  2. Constraining spatial variations in P-wave velocity in the upper mantle beneath SE Asia

    NARCIS (Netherlands)

    Li, C.; Hilst, R.D. van der; Toksoz, N.M.

    2006-01-01

    We have produced a P-wave model of the upper mantle beneath Southeast (SE) Asia from reprocessed short period International Seismological Centre (ISC) P and pP data, short period P data of the Annual Bulletin of Chinese Earthquakes (ABCE), and long period PP-P data.We used 3D sensitivity kernels

  3. From the Variscan to the Alpine Orogeny: crustal structure of the Bohemian Massif and the Western Carpathians in the light of the SUDETES 2003 seismic data

    Czech Academy of Sciences Publication Activity Database

    Hrubcová, Pavla; Środa, P.; Grad, M.; Geissler, W.H.; Guterch, A.; Vozár, J.; Hegedüs, E.

    2010-01-01

    Roč. 183, č. 2 (2010), s. 611-633 ISSN 0956-540X R&D Projects: GA ČR GAP210/10/2063 Institutional research plan: CEZ:AV0Z30120515 Keywords : controlled source seismology * body waves * continental margins: convergent * crustal structure * Europe Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.411, year: 2010

  4. Statistical properties of travel time measurements and the structure of the Earth's mantle

    NARCIS (Netherlands)

    Röhm, A.H.E.

    1999-01-01

    The Earth's deep interior is sampled daily by waves originating from earthquakes. Different types of waves gather information along various paths of propagation. Each seismogram recorded by one of the several hundred seismological stations is full of clues about the structure of the Earth.

  5. Moment tensor decompositions revisited

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav

    2015-01-01

    Roč. 19, č. 1 (2015), s. 231-252 ISSN 1383-4649 R&D Projects: GA ČR(CZ) GAP210/12/1491 Institutional support: RVO:67985530 Keywords : dynamics and mechanics of faulting * earthquake source observations * seismic anisotropy * theoretical seismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.550, year: 2015

  6. Proposals for regional cooperation in Africa

    International Nuclear Information System (INIS)

    Kleywegt, R.J.

    1999-01-01

    The CTBTO Prep Com is overseeing the rapid establishment of the verification-related means for the future CTBTO. It encourages support and participation in its development and would like to ensure that ancillary benefits are identified and utilised. One such benefit is to be derived from the global expertise, data and information which are developed and generated through its activities. This is particularly so in the field of seismology where the rapidly developing field of engineering seismology is dependent on quality data over an extended period. A national seismological capability is essential for countries that wish/expect to develop rapidly in the next few decades. Tremendous benefit can be derived by utilizing the verification-related monitoring data and information products of the CTBTO Prep Com, by making the organization (International Cooperation Section) aware of all national seismological needs and by interacting with member states. A regional co-operative programme or structure could be of benefit to countries to link with the CTBTO Prep Com in Vienna or for addressing problems common to a region. There are a number of regional organisations in Africa that can house or provide some form of support to further the cause of envisaged regional co-operative endeavours. The terms of reference and mechanisms by which the regional endeavours will operate should preferably be set up by the participating states within each region

  7. Iterative joint inversion for stress and fault orientations from focal mechanisms

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav

    2014-01-01

    Roč. 199, č. 1 (2014), s. 69-77 ISSN 0956-540X R&D Projects: GA ČR(CZ) GAP210/12/1491 Institutional support: RVO:67985530 Keywords : earthquake source observations * seismicity and tectonics * theoretical seismology Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.724, year: 2013

  8. Fault structure, frictional properties and mixed-mode fault slip behavior

    NARCIS (Netherlands)

    Collettini, C.; Niemeijer, A.; Viti, C.; Smith, S.A.F.; Marone, C.

    2011-01-01

    Recent high-resolution GPS and seismological data reveal that tectonic faults exhibit complex, multi-modeslipbehavior including earthquakes, creep events, slow and silent earthquakes, low-frequency events and earthquake afterslip. The physical processes responsible for this range of behavior and the

  9. The study of earthquakes in the hundred years following the Lisbon earthquake of 1755

    Czech Academy of Sciences Publication Activity Database

    Oldroyd, D. R.; Amador, F.; Kozák, Jan; Carneiro, A.; Pinto, M.

    2007-01-01

    Roč. 26, č. 2 (2007), s. 321-370 ISSN 0736-623X Institutional research plan: CEZ:AV0Z30120515 Keywords : 1755 Lisbon earthquake * post-Lisbon seismology * seismic waves Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  10. Bayesian ISOLA: new tool for automated centroid moment tensor inversion

    Czech Academy of Sciences Publication Activity Database

    Vackář, J.; Burjánek, Jan; Gallovič, F.; Zahradník, J.; Clinton, J.

    2017-01-01

    Roč. 210, č. 2 (2017), s. 693-705 ISSN 0956-540X Institutional support: RVO:67985530 Keywords : inverse theory * waveform inversion * computational seismology * earthquake source observations * seismic noise Subject RIV: DC - Siesmology, Volcanology, Earth Structure OBOR OECD: Volcanology Impact factor: 2.414, year: 2016

  11. Earthquake occurrence reveals magma ascent beneath volcanoes and seamounts in the Banda Region

    Czech Academy of Sciences Publication Activity Database

    Špičák, Aleš; Kuna, Václav; Vaněk, Jiří

    2013-01-01

    Roč. 75, č. 777 (2013), 777/1-777/8 ISSN 0258-8900 R&D Projects: GA MŠk ME09011 Institutional support: RVO:67985530 Keywords : Banda region * global seismological data * earthquake swarm Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.667, year: 2013

  12. Three-dimensional seismic velocity model of theWest Bohemia/Vogtland seismoactive region

    Czech Academy of Sciences Publication Activity Database

    Růžek, Bohuslav; Horálek, Josef

    2013-01-01

    Roč. 195, č. 2 (2013), s. 1251-1266 ISSN 0956-540X R&D Projects: GA ČR GAP210/12/2336; GA MŠk LM2010008 Institutional support: RVO:67985530 Keywords : controlled source seismology * body waves * seismic tomography * crustal structure Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.724, year: 2013

  13. Evaluation of seismic input for nuclear power plants; Evaluacion del input sismico para plantas nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Saragoni, G. R.

    2012-07-01

    The accident that affected the Fukushima Daiichi nuclear power plant on March 11th 2011 was the result of the Tohoku earthquake (Japan), the fifth largest ever registered in the world. The characteristics of the event will be a subject for study by the nuclear and seismology communities for many years to come. (Author)

  14. Constraints on mantle convection from seismic tomography

    NARCIS (Netherlands)

    Kárason, H.; Hilst, R.D. van der

    2000-01-01

    Since the advent of global seismic tomography some 25 years ago, advances in technology, seismological theory, and data acquisition have allowed spectacular progress in our ability to image seismic heterogeneity in Earth's mantle. We briefly review some concepts of seismic tomography, such as

  15. Fulltext PDF

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    sented and the maps are presented in the appropri- ate scales, in user-friendly formats and with clarity. With the objective of working towards effective procedures for microzonation of urban centers, the Programme Advisory and Monitoring Commit- tee (PAMC) of Seismology Division, Department of Science and Technology ...

  16. Příklady zemětřesení zaregistrovaných v hlubokém dole

    Czech Academy of Sciences Publication Activity Database

    Kaláb, Zdeněk; Lednická, Markéta

    2016-01-01

    Roč. 23, č. 1 (2016), s. 22-34 ISSN 1803-1447 R&D Projects: GA MŠk(CZ) LM2015079 Institutional support: RVO:68145535 Keywords : seismological measurement * earthquake * deep mine * vibration effect Subject RIV: DC - Siesmology, Volcanology, Earth Structure http://www.caag.cz/egrse-plne-texty.php

  17. Sandia National Laboratories/New Mexico Environmental Baseline update--Revision 1.0

    International Nuclear Information System (INIS)

    1996-07-01

    This report provides a baseline update to provide the background information necessary for personnel to prepare clear and consise NEPA documentation. The environment of the Sandia National Laboratories is described in this document, including the ecology, meteorology, climatology, seismology, emissions, cultural resources and land use, visual resources, noise pollution, transportation, and socioeconomics

  18. Sandia National Laboratories/New Mexico Environmental Baseline update--Revision 1.0

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-07-01

    This report provides a baseline update to provide the background information necessary for personnel to prepare clear and consise NEPA documentation. The environment of the Sandia National Laboratories is described in this document, including the ecology, meteorology, climatology, seismology, emissions, cultural resources and land use, visual resources, noise pollution, transportation, and socioeconomics.

  19. Is a Sunspot in Static or Dynamic Equilibrium?

    Indian Academy of Sciences (India)

    tribpo

    very high, leading to diffusion times that are much larger than the life time of the ... The way out of the apparent dilemma posed above is to have a spot in ... Recent work based on time distance seismology has indeed pointed towards such an.

  20. Summaries of physical research in the geosciences

    Energy Technology Data Exchange (ETDEWEB)

    1986-09-01

    The summaries in this document describe the scope of the individual programs and detail the research performed during 1984-1985. The Geosciences Research Program includes research in geology, petrology, geophysics, geochemistry, hydrology, solar-terrestrial relationships, aeronomy, seismology, and natural resource analysis, including their various subdivisions and interdisciplinary areas.

  1. Explanation of earthquake response spectra

    OpenAIRE

    Douglas, John

    2017-01-01

    This is a set of five slides explaining how earthquake response spectra are derived from strong-motion records and simple models of structures and their purpose within seismic design and assessment. It dates from about 2002 and I have used it in various introductory lectures on engineering seismology.

  2. The VERCE Science Gateway: Enabling User Friendly HPC Seismic Wave Simulations.

    Science.gov (United States)

    Casarotti, E.; Spinuso, A.; Matser, J.; Leong, S. H.; Magnoni, F.; Krause, A.; Garcia, C. R.; Muraleedharan, V.; Krischer, L.; Anthes, C.

    2014-12-01

    The EU-funded project VERCE (Virtual Earthquake and seismology Research Community in Europe) aims to deploy technologies which satisfy the HPC and data-intensive requirements of modern seismology.As a result of VERCE official collaboration with the EU project SCI-BUS, access to computational resources, like local clusters and international infrastructures (EGI and PRACE), is made homogeneous and integrated within a dedicated science gateway based on the gUSE framework. In this presentation we give a detailed overview on the progress achieved with the developments of the VERCE Science Gateway, according to a use-case driven implementation strategy. More specifically, we show how the computational technologies and data services have been integrated within a tool for Seismic Forward Modelling, whose objective is to offer the possibility to performsimulations of seismic waves as a service to the seismological community.We will introduce the interactive components of the OGC map based web interface and how it supports the user with setting up the simulation. We will go through the selection of input data, which are either fetched from federated seismological web services, adopting community standards, or provided by the users themselves by accessing their own document data store. The HPC scientific codes can be selected from a number of waveform simulators, currently available to the seismological community as batch tools or with limited configuration capabilities in their interactive online versions.The results will be staged out via a secure GridFTP transfer to a VERCE data layer managed by iRODS. The provenance information of the simulation will be automatically cataloged by the data layer via NoSQL techonologies.Finally, we will show the example of how the visualisation output of the gateway could be enhanced by the connection with immersive projection technology at the Virtual Reality and Visualisation Centre of Leibniz Supercomputing Centre (LRZ).

  3. A bibliography of IRIS-related publications, 2000-2011

    Science.gov (United States)

    Muco, B.

    2012-12-01

    Citations and acknowledgements in scientific journals can be an indicator of the role an organization has on the research of that field. Since its formation and incorporation in May 1984, the IRIS Consortium (Incorporated Research Institutions for Seismology) is mentioned more and more as a valuable source of data, instruments and programs in the literature of earth sciences. As a large organization with more than 100 member domestic institutes and about 40 international affiliates, obviously IRIS has a direct impact on the earth sciences through all its programs, projects, workshops, symposia, and news¬letters and as a lively forum for exchanging ideas. In order to maintain support from National Science Foundation (NSF) and the research community, it is important to document the continued use of IRIS facilities in basic research programs. IRIS maintains a database of articles that are based on the use of IRIS facilities or which reference use of IRIS data and resources. Articles in this database have been either been provided to IRIS by the authors or selected through an annual search of a number of prominent journals. A text version of the full bibliographic database is available on the IRIS website and a version in EndNote format is also provided. To provide a more complete bibliography and a consistent evaluation of temporal tends in publications, a special annual search began in 2000 which focused on a subset of key seismology and Earth science journals: Bulletin of Seismological Society of America, Journal of Geophysical Research, Seismological Research Letters, Geophysical Research Letters, Earth and Planetary Science Letters, Physics of the Earth and Planetary Interiors, Tectonophysics, Geophysical Journal International, Nature, Science, Geology and EOS. Using different search engines as Scirus, ScienceDirect, GeoRef, OCLC First Search, EASI Search, NASA Abstract Service etc. for online journals and publishers' databases, we searched for key words (IRIS

  4. The CE3R Network: current status and future perspectives

    Science.gov (United States)

    Lenhardt, Wolfgang; Pesaresi, Damiano; Živčić, Mladen; Costa, Giovanni; Kuk, Kresimir; Bondár, István; Duni, Llambro; Spacek, Petr

    2016-04-01

    In order to improve the monitoring of seismic activities in the border regions and to enhance the collaboration between countries and seismological institutions in Central Europe, the Environment Agency of the Slovenian Republic (ARSO), the Italian National Institute for Oceanography and Experimental Geophysics (OGS), the University of Trieste (UniTS) and the Austrian Central Institute for Meteorology and Geodynamics (ZAMG) established in 2001 the "South Eastern Alps Transfrontier Seismological Network". In May 2014 ARSO, OGS, UniTS and ZAMG agreed to formalize the transfrontier network, to name it "Central and East European Earthquake Research Network", (CE3RN or CE3R Network) in order to locate it geographically since cross-border networks can be established in other areas of the world and to expand their cooperation, including institutions in other countries. The University of Zagreb (UniZG) joined CE3RN in October 2014. The Kövesligethy Radó Seismological Observatory (KRSZO) of the Hungarian Academy of Sciences joined CE3RN in October 2015. The Institute of Geosciences, Energy, Water and Environment (IGEWE) of the Polytechnic University of Tirana joined CE3RN in November 2015. The Institute of Physics of the Earth (IPE) of the Masaryk University in Brno joined CE3RN in November 2015. CE3RN Parties intend to formalize and possibly extend their ongoing cooperation in the field of seismological data acquisition, exchange and use for seismological and earthquake engineering and civil protection purposes. The purpose of this cooperation is to retain and expand the existing cross-border network, specify the rules of conduct in the network management, improvements, extensions and enlargements, enhance seismological research in the region, and support civil protection activities. Since the formal establishment of CE3RN, several common projects have been completed, like the SeismoSAT project for the seismic data center connection over satellite funded by the Interreg

  5. 100 years of seismic research on the Moho

    DEFF Research Database (Denmark)

    Prodehl, Claus; Kennett, Brian; Artemieva, Irina

    2013-01-01

    on the Moho is primarily based on the comprehensive overview of the worldwide history of seismological studies of the Earth's crust using controlled sources from 1850 to 2005, by Prodehl and Mooney (2012). Though the art of applying explosions, so-called “artificial events”, as energy sources for studies......The detection of a seismic boundary, the “Moho”, between the outermost shell of the Earth, the Earth's crust, and the Earth's mantle by A. Mohorovičić was the consequence of increased insight into the propagation of seismic waves caused by earthquakes. This short history of seismic research...... of the uppermost crustal layers began in the early 1900s, its effective use for studying the entire crust only began at the end of World War II. From 1945 onwards, controlled-source seismology has been the major approach to study details of the crust and underlying crust–mantle boundary, the Moho. The subsequent...

  6. Brazilian participation in the International Monitoring System for Nuclear Explosions

    International Nuclear Information System (INIS)

    Veloso, Jose Alberto Vivas

    1995-01-01

    On January 1, 1995, Brazil was integrated to the world-wide seismic system, through the Seismological Observatory of the University of Brasilia, dedicated to detect and identify underground nuclear explosions. This is an unprecedented global effort program to conduct a seismic test of rapid data collection, distribution and processing evolving the most advanced sensors, global communications and data processing technologies. By the end of February, 49 countries were incorporated and the present test represents a first training step towards the final definition of an International Monitoring System to monitoring a Comprehensive test Band Treaty. Besides accomplishing its main goal, the global monitoring program will be able to supply rapidly, through the International Data Center, important information to the seismological community. (author). 2 figs

  7. How to create a very-low-cost, very-low-power, credit-card-sized and real-time-ready datalogger

    Science.gov (United States)

    Bès de Berc, M.; Grunberg, M.; Engels, F.

    2015-03-01

    In order to improve an existing network, a field seismologist would have to add some extra sensors to a remote station. However, additional ADCs (analogue-to-digital converters) are not always implemented on commercial dataloggers, or, if they are, they may already be used. Installing additional ADCs often implies an expensive development, or the purchase of a new datalogger. We present here a simple method to take advantage of the ADCs of an embedded computer in order to create data in a seismological standard format and integrate them within the real-time data stream from the station. Our first goal is to plug temperature and pressure sensors on the ADCs, read data and record them in mini-seed format (seed stands for Standard for the Exchange of the Earthquake Data), and eventually transfer them to a central server together with the seismic data, by using seedlink, since mini-seed and seedlink are standard for seismology.

  8. Birth of the Program for Array Seismic Studies of the Continental Lithosphere (PASSCAL)

    Science.gov (United States)

    James, D. E.; Sacks, I. S.

    2002-05-01

    As recently as 1984 institutions doing portable seismology depended upon their own complement of instruments, almost all designed and built in-house, and all of limited recording capability and flexibility. No data standards existed. Around 1980 the National Research Council (NRC) of the National Academy of Sciences (NAS), with National Science Foundation (NSF) support, empanelled a committee to study a major new initiative in Seismic Studies of the Continental Lithosphere (SSCL). The SSCL report in 1983 recommended that substantial numbers (1000 or more) of new generation digital seismographs be acquired for 3-D high resolution imaging of the continental lithosphere. Recommendations of the SSCL committee dovetailed with other NRC/NAS and NSF reports that highlighted imaging of the continental lithosphere as an area of highest priority. For the first time in the history of portable seismology the question asked was "What do seismologists need to do the job right?" A grassroots effort was undertaken to define instrumentation and data standards for a powerful new set of modern seismic research tools to serve the national seismological community. In the spring and fall of 1983 NSF and IASPEI sponsored workshops were convened to develop specifications for the design of a new generation of portable instrumentation. PASSCAL was the outgrowth of these seminal studies and workshops. The first step toward the formal formation of PASSCAL began with an ad-hoc organizing committee, comprised largely of the members of the NAS lithospheric seismology panel, convened by the authors at Carnegie Institution in Washington in November 1983. From that meeting emerged plans and promises of NSF support for an open organizational meeting to be held in January 1984, in Madison, Wisconsin. By the end of the two-day Madison meeting PASSCAL and an official consortium of seismological institutions for portable seismology were realities. Shortly after, PASSCAL merged with the complementary

  9. Preliminary code development for seismic signal analysis related to test ban treaty questions

    International Nuclear Information System (INIS)

    Brolley, J.E.

    1977-01-01

    Forensic seismology, from a present day viewpoint, appears to be divided into several areas. Overwhelmingly important, in view of current Complete Test Ban (CTB) discussions, is the seismological study of waves generated in the earth by underground nuclear explosions. Over the last two decades intensive effort has been devoted to developing improved observational apparatus and to the interpretation of the data produced by this equipment. It is clearly desirable to extract the maximum amount of information from seismic signals. It is, therefore, necessary to quantitatively compare various modes of analysis to establish which mode or combination of modes provides the most useful information. Preliminary code development for application of some modern developments in signal processing to seismic signals is described. Applications of noncircular functions are considered and compared with circular function results. The second portion of the discussion concerns maximum entropy analysis. Lastly, the multivariate aspects of the general problem are considered

  10. Practical domain for ultrasonic testing of stainless steel over plain carbon steel layered components using M21 waves

    International Nuclear Information System (INIS)

    Grewal, D.S.; Bray, D.E.

    1995-01-01

    The first higher order mode of the Rayleigh wave was discussed by Sezawa in the early part of this century in context of seismological wave studies. These Sezawa, or M 21 , or first higher order mode Rayleigh waves, have subsequently been used in the field of nondestructive testing of layered materials based on the development of the seismological model of the Sezawa waves by others. In this paper the study of the Tiersten formulation in context with slow speed over high speed materials, e.g. stainless steel overlay on plain carbon steel, the limitations and applicability of that formulation is reported. This study illustrates the practical bounds for testing such layered media, using numerical analysis of this formulation for the first higher-order mode to establish theoretical limits, and corroboration of these bounds by experimental results

  11. An attempt to model the relationship between MMI attenuation and engineering ground-motion parameters using artificial neural networks and genetic algorithms

    Directory of Open Access Journals (Sweden)

    G-A. Tselentis

    2010-12-01

    Full Text Available Complex application domains involve difficult pattern classification problems. This paper introduces a model of MMI attenuation and its dependence on engineering ground motion parameters based on artificial neural networks (ANNs and genetic algorithms (GAs. The ultimate goal of this investigation is to evaluate the target-region applicability of ground-motion attenuation relations developed for a host region based on training an ANN using the seismic patterns of the host region. This ANN learning is based on supervised learning using existing data from past earthquakes. The combination of these two learning procedures (that is, GA and ANN allows us to introduce a new method for pattern recognition in the context of seismological applications. The performance of this new GA-ANN regression method has been evaluated using a Greek seismological database with satisfactory results.

  12. The seismicity related to the southern part of the Kenya Rift

    Science.gov (United States)

    Hollnack, D.; Stangl, R.

    1998-04-01

    In 1990 the Geology Department of the University of Nairobi started to build up a seismological network for Kenya, which has been operating since 1993. In this paper the actual state of this seismological network is described. Additionally, the first results on the seismic activity in the southern part of Kenya and adjacent areas between October 1993 and August 1996 are presented and are compared with historical data. Out of more than 2000 recorded local earthquakes 435 could be localised within the study area with local magnitudes of up to 5. The distribution of the events shows three areas of prominent seismicity: the Rift Valley between Nakuru and northern Tanzania; the area northeast of Kilimanjaro; and the Nyanza Rift in western Kenya. In a first attempt to assess the seismic hazard for the study area, a seismic energy map for the period of observation is given.

  13. Site selection for nuclear power plants and geologic seismologia influence

    International Nuclear Information System (INIS)

    Castro Feitosa, G. de.

    1985-01-01

    The site selection for nuclear power plants is analised concerning to the process, methodology and the phases in an overall project efforts. The factors affecting are analised on a general viewpoint, showing the considerations given to every one. The geologic and seismologic factors influence on the foundation design are more detailed analised, with required investigation and procedures accordingly sub-soil conditions in the site [pt

  14. 100 years of seismic research on the Moho

    Science.gov (United States)

    Prodehl, Claus; Kennett, Brian; Artemieva, Irina M.; Thybo, Hans

    2013-12-01

    The detection of a seismic boundary, the “Moho”, between the outermost shell of the Earth, the Earth's crust, and the Earth's mantle by A. Mohorovičić was the consequence of increased insight into the propagation of seismic waves caused by earthquakes. This short history of seismic research on the Moho is primarily based on the comprehensive overview of the worldwide history of seismological studies of the Earth's crust using controlled sources from 1850 to 2005, by Prodehl and Mooney (2012). Though the art of applying explosions, so-called “artificial events”, as energy sources for studies of the uppermost crustal layers began in the early 1900s, its effective use for studying the entire crust only began at the end of World War II. From 1945 onwards, controlled-source seismology has been the major approach to study details of the crust and underlying crust-mantle boundary, the Moho. The subsequent description of history of controlled-source crustal seismology and its seminal results is subdivided into separate chapters for each decade, highlighting the major advances achieved during that decade in terms of data acquisition, processing technology, and interpretation methods. Since the late 1980s, passive seismology using distant earthquakes has played an increasingly important role in studies of crustal structure. The receiver function technique exploiting conversions between P and SV waves at discontinuities in seismic wavespeed below a seismic station has been extensively applied to the increasing numbers of permanent and portable broad-band seismic stations across the globe. Receiver function studies supplement controlled source work with improved geographic coverage and now make a significant contribution to knowledge of the nature of the crust and the depth to Moho.

  15. The limits of earthquake early warning: Timeliness of ground motion estimates

    OpenAIRE

    Minson, Sarah E.; Meier, Men-Andrin; Baltay, Annemarie S.; Hanks, Thomas C.; Cochran, Elizabeth S.

    2018-01-01

    The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a distance from the earthquake, assuming that the earthquake magnitude is not predictable. Earthquake early warning (EEW) systems are in operation or development for many regions aroun...

  16. Bollettino Sismico Italiano: novità

    OpenAIRE

    Nardi, A.; Marchetti, A.; Modica, G.; Battelli, P.; Berardi, M.; Castellano, C.; Melorio, C.; Pirro, M.; Rossi, A.; Spadoni, S.; Arcoraci, L.; Lozzi, G.; Battelli, A.; Thermes, C.; Ciaccio, M.G.

    2015-01-01

    I parametri dei terremoti registrati dalla Rete Sismica Nazionale Italiana, localizzati nella sala di sorveglianza sismica dell’INGV, sono immediatamente disponibili sul web alla pagina http://cnt.rm.ingv.it/ e nell’Italian Seismological Instrumental and parametric Data-base (ISIDe; Mele et al. 2007) http://iside.rm.ingv.it/iside/standard/index.jsp. Questi eventi sono in seguito revisionati dagli analisti del Bollettino. Gli analisti ricontrollano i parametri di tutti i terremoti ottenuti ins...

  17. Gaussian beams in inhomogeneous anisotropic layered structures

    Czech Academy of Sciences Publication Activity Database

    Červený, V.; Pšenčík, Ivan

    2010-01-01

    Roč. 180, č. 2 (2010), s. 798-812 ISSN 0956-540X R&D Projects: GA ČR GA205/08/0332 Grant - others:GA ČR(CZ) GA205/07/0032 Institutional research plan: CEZ:AV0Z30120515 Keywords : body waves * seismic anisotropy * theoretical seismology * wave propagation Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.411, year: 2010

  18. The VELA Program. A Twenty-Five Year Review of Basic Research

    Science.gov (United States)

    1985-01-01

    Number 4 is the source of much of the money that was for support of seismological community for a better understanding of detection and identification...path 40.0 1 2.0 2.5 3.0 3.5 4.0 4.5 Shear velocity in km/sec NTS Area Crustal Velocity and Q Structure from Broadband Surface Waves Fig. 3. NTS Lauders

  19. Dynamics and Stability of Acoustic Wavefronts in the Ocean

    Science.gov (United States)

    2014-09-30

    method employed in (Godin, 2003, 2007, 2009), where a novel perturbation technique has been developed to solve the eikonal equation and calculate...numerical solution of the eikonal equation lies in the eikonal (and acoustic travel time) being a multi-valued function of position. A number of...computational approaches to solve the eikonal equation without ray tracing had been developed in mathematical and seismological communities (Vidale, 1990

  20. Shaking table testing of mechanical components

    International Nuclear Information System (INIS)

    Jurukovski, D.; Taskov, Lj.; Mamucevski, D.; Petrovski, D.

    1995-01-01

    Presented is the experience of the Institute of Earthquake Engineering and Engineering Seismology, Skopje, Republic of Macedonia in seismic qualification of mechanical components by shaking table testing. Technical data and characteristics for the three shaking tables available at the Institute are given. Also, for characteristic mechanical components tested at the Institute laboratories, basic data such as producer, testing investor, description of the component, testing regulation, testing equipment and final user of the results. (author)

  1. Toward understanding subtle instrumentation effects associated with weak seismic events in the near field

    Czech Academy of Sciences Publication Activity Database

    Zahradník, J.; Plešinger, Axel

    2010-01-01

    Roč. 100, č. 1 (2010), s. 59-73 ISSN 0037-1106 R&D Projects: GA AV ČR IAA300120911 Grant - others:GA ČR(CZ) GA205/07/0502 Institutional research plan: CEZ:AV0Z30120515 Keywords : instrumentation effects * broadband seismology * weak earthquakes Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.027, year: 2010

  2. Rotaphone, a mechanical seismic sensor system for field rotation rate measurements and its in situ calibration

    Czech Academy of Sciences Publication Activity Database

    Brokešová, J.; Málek, Jiří; Kolínský, Petr

    2012-01-01

    Roč. 16, č. 4 (2012), s. 603-621 ISSN 1383-4649 R&D Projects: GA ČR GAP210/10/0925 Grant - others:GA MŠk(CZ) LM2010008 Program:LM Institutional support: RVO:67985891 Keywords : rotational seismology * sensor * six-degree-of-freedom Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.388, year: 2012

  3. Testing of components on the shaking table facilities of AEP and contribution to full scale dynamic testing of Kozloduy NPP. Final report

    International Nuclear Information System (INIS)

    Ambriashvili, Y.

    1999-01-01

    Units 5 and 6 of the Kozloduy NPP were designed as a standardized WWER-1000 on the basis standardized scheme designs, including building structures and reactor building. The accelerograms and response spectrum were adopted based on seismological, geological, geophysical and other conditions of the region where the NPP is expected to be located. This paper presents the results design floor response spectra analysis as well as method and some results of the tests of electrical equipment as identified by the Kozloduy NPP staff

  4. Development of requirements for seismic upgrading of equipment of existing WWER-440 and WWER-1000 type NPPs

    International Nuclear Information System (INIS)

    Kaznovsky, S.; Ostretsov, I.

    1993-01-01

    The change in seismology data and safety demands a necessity arose for seismic upgrading of the existing operating NPPs of WWER type which have been originally designed and built without or with simplifies calculations of seismic influences. The paper describes the traditional methods and approaches and calculation-experimental method for examining and ensuring of equipment seismic resistance at the NPPs directly. Method of ground explosions is included as well

  5. Moment tensor inversion of waveforms: a two-step time-frequency approach

    Czech Academy of Sciences Publication Activity Database

    Vavryčuk, Václav; Kühn, D.

    2012-01-01

    Roč. 190, č. 3 (2012), s. 1761-1776 ISSN 0956-540X R&D Projects: GA AV ČR IAA300120801; GA ČR(CZ) GAP210/12/1491 Institutional research plan: CEZ:AV0Z30120515 Keywords : earthquake source observations * computational seismology * wave propagation * dynamics and mechanics of faulting Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.853, year: 2012

  6. United States Earthquake Early Warning System: How Theory and Analysis Can Save America Before the Big One Happens

    Science.gov (United States)

    2017-12-01

    Documentation for 201447 Spending more on ShakeAlert now and including sustainable operating costs can be justified. In a 2016 publication in...Seismological Research Letters, entitled “ Benefits and Costs of Earthquake Early Warning,” Strauss and Allen determine that “according to FEMA’s cost ...statistical life in the United States is USD 6.6 million.”48 As such, the benefits outweigh the costs as the earthquake early warning system alone would

  7. Gorbachev’s Arms Control Strategy.

    Science.gov (United States)

    1987-01-22

    on- site inspection for verifying nuclear tests as well as for dismantling missiles on Soviet territory. Clearlv Gorbachev wants an arms , -4- control...bring its seismological test equipment to what he called the "holy of holies", the area adjoining the Soviet proving ground near Semipalatinsk to offer...prenotification and observation of military exercises including on- site inspection on Soviet territory. But on the big issues--- nuclear testing , strategic weapons

  8. Fast nonlinear gravity inversion in spherical coordinates with application to the South American Moho

    Science.gov (United States)

    Uieda, Leonardo; Barbosa, Valéria C. F.

    2017-01-01

    Estimating the relief of the Moho from gravity data is a computationally intensive nonlinear inverse problem. What is more, the modelling must take the Earths curvature into account when the study area is of regional scale or greater. We present a regularized nonlinear gravity inversion method that has a low computational footprint and employs a spherical Earth approximation. To achieve this, we combine the highly efficient Bott's method with smoothness regularization and a discretization of the anomalous Moho into tesseroids (spherical prisms). The computational efficiency of our method is attained by harnessing the fact that all matrices involved are sparse. The inversion results are controlled by three hyperparameters: the regularization parameter, the anomalous Moho density-contrast, and the reference Moho depth. We estimate the regularization parameter using the method of hold-out cross-validation. Additionally, we estimate the density-contrast and the reference depth using knowledge of the Moho depth at certain points. We apply the proposed method to estimate the Moho depth for the South American continent using satellite gravity data and seismological data. The final Moho model is in accordance with previous gravity-derived models and seismological data. The misfit to the gravity and seismological data is worse in the Andes and best in oceanic areas, central Brazil and Patagonia, and along the Atlantic coast. Similarly to previous results, the model suggests a thinner crust of 30-35 km under the Andean foreland basins. Discrepancies with the seismological data are greatest in the Guyana Shield, the central Solimões and Amazonas Basins, the Paraná Basin, and the Borborema province. These differences suggest the existence of crustal or mantle density anomalies that were unaccounted for during gravity data processing.

  9. Aspects of sismo-tectonic stability in the South-Eastern region of Brazil of interest to geology of engineering

    International Nuclear Information System (INIS)

    Mioto, J.A.; Hasui, Y.

    1982-01-01

    The occurence of earthquakes in Brazil, mainly in the South-eastern region, and its relationship with the geologic features has been discussed by many Authors since the beginning of this Century. It is difficult to define intraplate seismicity and to understand the actual epirogenic displacent, but the definition of the regional stability is important for enginnering purposes and have been considered through seismologic, morphotectonic and geologic criteria. (Author) [pt

  10. Research and development activities of High Pressure Physics Division (October 1993 - March 1996)

    Energy Technology Data Exchange (ETDEWEB)

    Gyanchandani, Jyoti; Gangrade, B K [eds.; High Pressure Physics Div., Bhabha Atomic Research Centre, Mumbai (India)

    1996-07-01

    The research and development activities of the High Pressure Physics Division during the period October 1993-March 1996 are reported in the form of collection of papers presented in journals, conference proceedings and abstracts in conferences and Bhabha Atomic Research Centre (BARC) technical reports. The report is organised in two sections: (A) High Pressure Physics Division, and (B) Seismology Section. A list of staff members is enclosed at the end.

  11. Continuation of the summarizing interim report on previous results of the Gorleben site survey as of May 1983

    International Nuclear Information System (INIS)

    1990-04-01

    In addition to results from the 1983 interim report, this report contains, in order to supplement the surface explorations, seismic reflection measurements, hydrogeologic and seismologic investigations, sorption experiments, and studies of glacial development in the site region and of long-term safety of final waste repositories in salt domes. The site's high grade of suitability for becoming a final radioactive waste repository, the legal basis as well as quality assurance are evaluated. (orig.) [de

  12. Long-term development of seismic monitoring networks in the Ostrava-Karviná coal mine district

    Czech Academy of Sciences Publication Activity Database

    Holub, Karel; Holečko, J.; Rušajová, Jana; Dombková, Anna

    2012-01-01

    Roč. 166, č. 2 (2012), s. 115-132 ISSN 1214-9705 Institutional research plan: CEZ:AV0Z30860518 Keywords : Ostrava _Karviná Coal Basin * seismoacoustic and seismological monitoring * geomechanical service Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 0.530, year: 2011 http://www.irsm.cas.cz/abstracts/AGG/02_12/1_Holub.pdf

  13. Source mechanisms of micro-earthquakes induced in a fluid injection experiment at the HDR site Soultz-sous-Forêts (Alsace) in 2003 and their temporal and spatial variations

    Czech Academy of Sciences Publication Activity Database

    Horálek, Josef; Jechumtálová, Zuzana; Dorbath, L.; Šílený, Jan

    2010-01-01

    Roč. 181, č. 3 (2010), s. 1547-1565 ISSN 0956-540X R&D Projects: GA AV ČR IAA300120911; GA ČR GA205/09/0724 Grant - others:EU(XE) MTKI-CT-2004-517242 Institutional research plan: CEZ:AV0Z30120515 Keywords : downhole methods * hydrogeophysics * controlled source seismology * earthquake source observations * fracture and flow Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.411, year: 2010

  14. Proceedings of a specialist meeting on the anti-seismic design of nuclear installations

    International Nuclear Information System (INIS)

    1976-01-01

    This meeting is composed of 26 papers, grouped into 6 sessions. Session I: Introduction (reports on previous meetings related to seismic issues and mechanical structures for nuclear power plants). Session II: seismology. Session III: soil-foundation interaction. Session IV: structures and equipment; Session V: experimental techniques and instrumentation of power plants. Session VI: Synthesis and regulations. Each session is followed by a general discussion. The meeting is concluded with the chairman's report

  15. Tunable compact mechanical monolithic sensors for linear and angular large band low-frequency monitoring and characterization of sites and structures

    Science.gov (United States)

    Barone, F.; Giordano, G.; Acernese, F.; Romano, R.

    2017-10-01

    In this paper we present monolithic implementations of tunable mechanical seismometers and accelerometers (horizontal, vertical and angular) based on the UNISA Folded Pendulum configuration, characterized by large measurement band 10-7 ÷ 1 kHz, sensitivity down to ≈ 10-15 m/√ Hz, high directivity > 104 , low weight engineering, seismology, geophysics, civil engineering (buildings, bridges, dams, etc.), space (inertial guide).

  16. Bridging the Gap - Networking Educators using Real-Time Seismic Data

    Science.gov (United States)

    Ortiz, A. M.; Renwald, M. D.; Baldwin, T. K.; Hall, M. K.

    2004-12-01

    After nearly a decade, the seismology community has made critical advances in identifying what is effective and what is needed for success in incorporating real-time seismic data in the classroom. Today's K-16 classroom teachers have many options and opportunities for incorporating short- and long-term inquiry activities for monitoring earthquakes and analyzing seismic data in their daily instruction. Through the SpiNet program, we are providing web-based tools that support educators working with real-time seismic data (http://www.scieds.com/spinet/). Our site includes a Recent Seismicity section, which allows users to share seismic data in real-time, and provides near real-time information about global seismicity. Our Activities section provides data and lessons to assist educators who wish to integrate seismology into their classroom. The Research section, currently under development, will allow educators to share general information about how they teach seismology in their classroom through a discussion board and by posting lesson plans. In addition, we are developing a user-friendly tool for students to post results of their research projects. Designing a website which targets a range of users requires a working knowledge of both user needs and website programming and design. User needs include providing a logical navigational structure and accounting for differences in browser functionality, internet access, and users' abilities. Using website development tools, such as PHP, MySQL, RDF feeds, and specialized geoscience applications, we are automating site maintenance; incorporating databases for information storage and retrieval; and providing accessibility for users with a range of skills and physical limitations. By incorporating these features, we have built a dynamic interface for a broad range of users interested in educational seismology.

  17. Formulation de la tomographie des temps de première arrivée à partir d'une méthode de gradient : un pas vers une tomographie interactive

    OpenAIRE

    Taillandier , Cédric

    2008-01-01

    First arrival traveltime tomography aims at inferring a seismic wave propagation velocity model from first arrival traveltimes picked on seismograms. The velocity model inferred can be used directly to perform a structural interpretation of the subsurface or as an initial model for another seismic imaging method. This technique can be applied at different scales from geotechnical studies to seismology through oil exploration. The geophysicist know-how plays an important role in the difficult ...

  18. INEL environmental characterization report. Volume II. Appendices A-D

    International Nuclear Information System (INIS)

    1984-09-01

    This volume contains appendices: (1) a socioeconomic data base for southeastern Idaho; (2) an ecological characterization of the INEL; (3) site-specific climatology summary, NPR primary and alternate sites; (4) NPR site borehole completion; (5) an investigation of the principal lineament at the INEL; (6) an investigation of Clay Butte, Idaho; (7) Arco and Howe fault study; (8) seismology of the INEL; (9) geologic map of the INEL; and (1) geologic ages of the INEL

  19. Experimentální měření seismických účinků trhacích prací v historickém Dole Jeroným

    Czech Academy of Sciences Publication Activity Database

    Kaláb, Zdeněk; Knejzlík, Jaromír

    2004-01-01

    Roč. 4, č. 2 (2004), s. 159-166 ISSN 1213-1962. [Development of seismology, engineering geophysics and geotechnique/13./. Ostrava, 30.03.2004-01.04.2004] R&D Projects: GA AV ČR KSK3012103; GA ČR GA105/04/1424 Institutional research plan: CEZ:AV0Z3086906 Keywords : blastings * seismic measurement Subject RIV: DC - Siesmology, Volcanology, Earth Structure

  20. Microearthquake mechanism from wave amplitudes recorded by a close-to-surface seismic array at Ocnele Mari, Romania

    Czech Academy of Sciences Publication Activity Database

    Jechumtálová, Zuzana; Šílený, Jan; Trifu, C.-I.

    2014-01-01

    Roč. 197, č. 3 (2014), s. 1608-1626 ISSN 0956-540X R&D Projects: GA ČR GAP210/10/1728; GA ČR GAP210/12/2235 EU Projects: European Commission(XE) 230669 - AIM Institutional support: RVO:67985530 Keywords : inverse theory * earthquake source observation * computational seismology * fractures and faults * mechanic, theory, and modelling Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 2.724, year: 2013