Science.gov

Sample records for active source seismology

  1. Active region seismology

    NASA Technical Reports Server (NTRS)

    Bogdan, Tom; Braun, D. C.

    1995-01-01

    Active region seismology is concerned with the determination and interpretation of the interaction of the solar acoustic oscillations with near-surface target structures, such as magnetic flux concentration, sunspots, and plage. Recent observations made with a high spatial resolution and a long temporal duration enabled measurements of the scattering matrix for sunspots and solar active regions to be carried out as a function of the mode properties. Based on this information, the amount of p-mode absorption, partial-wave phase shift, and mode mixing introduced by the sunspot, could be determined. In addition, the possibility of detecting the presence of completely submerged magnetic fields was raised, and new procedures for performing acoustic holography of the solar interior are being developed. The accumulating evidence points to the mode conversion of p-modes to various magneto-atmospheric waves within the magnetic flux concentration as being the unifying physical mechanism responsible for these diverse phenomena.

  2. Crustal composition in southern Norway from active and passive source seismology

    NASA Astrophysics Data System (ADS)

    Stratford, W. R.; Frassetto, A. M.; Thybo, H.

    2010-12-01

    Crustal composition and structure beneath the Fennoscandian shield are highly variable due to the method of crustal accretion and the long history of extensional and compressional tectonics. In southern Norway, the Moho and crust are inferred to be the youngest of the shield, however, it is likely that a large discrepancy between crustal age and Moho age exists beneath the high southern Scandes where the Caledonian orogeny was in effect and beneath the Oslo Graben where 60 million years of rifting and magmatism has altered the crust. Crustal structure in southern Norway was targeted with a multi-disciplinary seismic study (Magnus-Rex - Mantle investigations of Norwegian uplift Structure). Three ~400 km long active source seismic profiles across the southern Norway and a region wide array of broadband seismometers were deployed. P and S-wave arrivals were recorded in the Magnus-Rex project, from which Poisson ratios for the crust in southern Norway are calculated from both active source profiling and receiver functions. Unusually strong S-wave arrivals allow rare insight into crustal Poisson’s ratio structure, within crustal layers, that is not normally available from active source data and are usually determined by earthquake tomography studies where only bulk crustal values are available. An average Poisson’s ratio of 0.25 is calculated for the crust in southern Norway, suggesting it is predominantly of felsic-intermediate composition and lacks any significant mafic lower crust. This differs significantly from the adjacent crust in the Svecofennian domain of the Fennoscandian shield where Moho depths reach ~50 km and an up to 20 km thick mafic lower crust is present. The vast difference in Moho depths in the Fennoscandian shield are, therefore, mostly due to the variation in thickness of the high Vp lower crust. Estimates of crustal composition and the effect of Magma intrusion within the Oslo Graben, and possible delamination of the lowermost crust beneath

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

    NASA Astrophysics Data System (ADS)

    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

  4. Seismology.

    ERIC Educational Resources Information Center

    Bollinger, G. A.

    1983-01-01

    Seismic events which took place during 1982 form the focus of this review on 1982 seismic research activities and projects. Funding problems for local and other networks, earthquake-prediction research (funded by National Earthquake Hazards Reduction Act of 1977: P.L. 95-124), use of computers, and aftershocks are among the areas addressed. (JN)

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  6. Powerful Low-Frequency Vibrators for Active Seismology

    SciTech Connect

    Alekseev, A.S.; Chichinin, I.S.; Korneev, V.A.

    2003-12-01

    In the past two decades, active seismology studies in Russia have made use of powerful (40- and 100-ton) low-frequency vibrators. These sources create a force amplitude of up to 100 tons and function in the 1.5 3, 3 6, and 5 10 Hz frequency bands. The mobile versions of the vibrator have a force amplitude of 40 tons and a 6 12 Hz frequency band. Recording distances for the 100-ton vibrator are as large as 350 km, enabling the refracted waves to penetrate down to 50 km depths. Vibrator operation sessions are highly repeatable, having distinct summer or winter spectral patterns. A long profile of seismic records allows estimation of fault zone depths using changes in recorded spectra. Other applications include deep seismic profiling, seismic hazard mapping, structural testing, stress-induced anisotropy studies, seismic station calibration, and large-structure integrity testing. The theoretical description of the low-frequency vibrator is given in the appendices, which contain numerical examples.

  7. Combining controlled-source seismology and receiver function information to derive 3-D Moho topography for Italy

    NASA Astrophysics Data System (ADS)

    Spada, M.; Bianchi, I.; Kissling, E.; Agostinetti, N. Piana; Wiemer, S.

    2013-08-01

    The accurate definition of 3-D crustal structures and, in primis, the Moho depth, are the most important requirement for seismological, geophysical and geodynamic modelling in complex tectonic regions. In such areas, like the Mediterranean region, various active and passive seismic experiments are performed, locally reveal information on Moho depth, average and gradient crustal Vp velocity and average Vp/Vs velocity ratios. Until now, the most reliable information on crustal structures stems from controlled-source seismology experiments. In most parts of the Alpine region, a relatively large number of controlled-source seismology information are available though the overall coverage in the central Mediterranean area is still sparse due to high costs of such experiments. Thus, results from other seismic methodologies, such as local earthquake tomography, receiver functions and ambient noise tomography can be used to complement the controlled-source seismology information to increase coverage and thus the quality of 3-D crustal models. In this paper, we introduce a methodology to directly combine controlled-source seismology and receiver functions information relying on the strengths of each method and in relation to quantitative uncertainty estimates for all data to derive a well resolved Moho map for Italy. To obtain a homogeneous elaboration of controlled-source seismology and receiver functions results, we introduce a new classification/weighting scheme based on uncertainty assessment for receiver functions data. In order to tune the receiver functions information quality, we compare local receiver functions Moho depths and uncertainties with a recently derived well-resolved local earthquake tomography-derived Moho map and with controlled-source seismology information. We find an excellent correlation in the Moho information obtained by these three methodologies in Italy. In the final step, we interpolate the controlled-source seismology and receiver functions

  8. The real evidence of effects from source to freefield as base for nonlinear seismology

    NASA Astrophysics Data System (ADS)

    Marmureanu, Gheorghe; Marmureanu, Alexandru; Ortanza Cioflan, Carmen-; -Florinela Manea, Elena

    2014-05-01

    Authors developed in last time the concept of "Nonlinear Seismology-The Seismology of the XXI Century". Prof. P. M. Shearer, California Univ. in last book:(i) Strong ground accelerations from large earthquakes can produce a non-linear response in shallow soils; (ii) The shaking from large earthquakes cannot be predicted by simple scaling of records from small earthquakes; (iii) This is an active area of research in strong motion and engineering seismology. Aki: Nonlinear amplification at sediments sites appears to be more pervasive than seismologists used to think. Any attempt at seismic zonation must take into account the local site condition and this nonlinear amplification (Tectonophysics, 218, 93-111, 1993). The difficulty to seismologists in demonstrating the nonlinear site effects has been due to the effect being overshadowed by the overall patterns of shock generation and propagation. In other words, the seismological detection of the nonlinear site effects requires a simultaneous understanding and splitting up (if it is possible…and if it is necessary!) the effects of earthquake source, propagation path and local geological site conditions. To see the actual influence of nonlinearity of the whole system (seismic source-path propagation-local geological structure) the authors used to study the free field response spectra which are the last in this chain and they are the ones who are taken into account in seismic design of all structures. Soils from last part of this system(source-freefield) exhibit a strong nonlinear behaviour under cyclic loading conditions and although have many common mechanical properties require the use of different models to describe behavior differences. Sands typically have low rheological properties and can be modeled with an acceptable linear elastic model and clays which frequently presents significant changes over time can be modeled by a nonlinear viscoelastic model The real evidence of site effects from source to freefield

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

    SciTech Connect

    Abdelwahed, Mohamed F.

    2012-09-26

    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.

  10. Engineering seismology

    USGS Publications Warehouse

    N.N, Ambraseys

    1991-01-01

    Twenty years have elasped since the first issue of Earthquakes & Volcanoes. Apart from the remarkable increases in the number of scientists actively enagaged in earth sciences, what are the outstanding achievements during the past 20 years in the field of engineering seismology, which is my own speciality?

  11. Volcano seismology

    USGS Publications Warehouse

    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

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

    NASA Astrophysics Data System (ADS)

    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. Exploring the Earth's crust: history and results of controlled-source seismology

    USGS Publications Warehouse

    Prodehl, Claus; Mooney, Walter D.

    2012-01-01

    This volume contains a comprehensive, worldwide history of seismological studies of the Earth’s crust using controlled sources from 1850 to 2005. Essentially all major seismic projects on land and the most important oceanic projects are covered. The time period 1850 to 1939 is presented as a general synthesis, and from 1940 onward the history and results are presented in separate chapters for each decade, with the material organized by geographical region. Each chapter highlights the major advances achieved during that decade in terms of data acquisition, processing technology, and interpretation methods. For all major seismic projects, the authors provide specific details on field observations, interpreted crustal cross sections, and key references. They conclude with global and continental-scale maps of all field measurements and interpreted Moho contours. An accompanying DVD contains important out-of-print publications and an extensive collection of controlled-source data, location maps, and crustal cross sections.

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

    NASA Astrophysics Data System (ADS)

    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

  15. Ambient noise as the new source for urban engineering seismology and earthquake engineering: a case study from Beijing metropolitan area

    NASA Astrophysics Data System (ADS)

    Liu, Lanbo; Chen, Qi-fu; Wang, Weijun; Rohrbach, Eric

    2014-02-01

    In highly populated urban centers, traditional seismic survey sources can no longer be properly applied due to restrictions in modern civilian life styles. The ambient vibration noise, including both microseisms and microtremor, though are generally weak but available anywhere and anytime, can be an ideal supplementary source for conducting seismic surveys for engineering seismology and earthquake engineering. This is fundamentally supported by advanced digital signal processing techniques for effectively extracting the useful information out from the noise. Thus, it can be essentially regarded as a passive seismic method. In this paper we first make a brief survey of the ambient vibration noise, followed by a quick summary of digital signal processing for passive seismic surveys. Then the applications of ambient noise in engineering seismology and earthquake engineering for urban settings are illustrated with examples from Beijing metropolitan area. For engineering seismology the example is the assessment of site effect in a large area via microtremor observations. For earthquake engineering the example is for structural characterization of a typical reinforced concrete high-rise building using background vibration noise. By showing these examples we argue that the ambient noise can be treated as a new source that is economical, practical, and particularly valuable to engineering seismology and earthquake engineering projects for seismic hazard mitigation in urban areas.

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

    NASA Astrophysics Data System (ADS)

    Mathur, Savita

    2015-09-01

    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.

  17. SOI/MDI studies of active region seismology and evolution

    NASA Technical Reports Server (NTRS)

    Tarbell, Ted D.; Title, Alan; Hoeksema, J. Todd; Scherrer, Phil; Zweibel, Ellen

    1995-01-01

    The solar oscillations investigation (SOI) will study solar active regions using both helioseismic and conventional observation techniques. The Michelson Doppler imager (MDI) can perform Doppler continuum and line depth imagery and can produce longitudinal magnetograms, showing either the full disk or a high resolution field of view. A dynamics program of continuous full disk Doppler observations for two months per year, campaign programs of eight hours of continuous observation per day, and a synoptic magnetic program of about 15 full disk magnetograms per day, are planned. The scientific plans, measurements and observation programs, are described.

  18. Integrating seismological and geodetic datasets: New insights into the seismic source

    NASA Astrophysics Data System (ADS)

    O'Toole, T. B.; Valentine, A. P.; Gilligan, A.; Woodhouse, J. H.

    2010-12-01

    Seismometers and continuous GPS receivers provide two different methods by which deformations arising from the same physical process, earthquake faulting, may be recorded. Despite this, studies of the seismic source have generally exploited only one or other of these techniques. Can new insights into earthquake sources and Earth structure be gained by combining multiple data types? Seismological studies of Earth processes and properties require observations of the seismic wavefield, and have typically been performed using only acceleration seismograms. If this dataset were to be augmented with continuous GPS time-series, which have different frequency and amplitude sensitivities, additional information on model parameters might be obtained. In any case, attempts must be made to construct models that simultaneously satisfy all the available data types. The first challenge in doing so is developing an understanding of how datasets might usefully be combined. Seismic source determination lends itself to this challenge because it is a relatively straightforward and and well understood problem. We have developed a new method to calculate complete synthetic displacement seismograms that include the static deformation, in a plane layered elastic earth model [1]. This method is appropriate for obtaining theoretical GPS time-series arising from moderately sized earthquakes for near-field stations. Our implementation allows CMT style source inversions to be carried out using continuous GPS data alone and in combination with long period teleseismic data. This application is demonstrated using time-series acquired for a recent Mw 6.9 earthquake. References: [1] O'Toole & Woodhouse, Numerically Stable Computation of Complete Synthetic Seismograms In Plane Layered Media, in prep.

  19. Linking petrology and seismology at an active volcano.

    PubMed

    Saunders, Kate; Blundy, Jon; Dohmen, Ralf; Cashman, Kathy

    2012-05-25

    Many active volcanoes exhibit changes in seismicity, ground deformation, and gas emissions, which in some instances arise from magma movement in the crust before eruption. An enduring challenge in volcano monitoring is interpreting signs of unrest in terms of the causal subterranean magmatic processes. We examined over 300 zoned orthopyroxene crystals from the 1980-1986 eruption of Mount St. Helens that record pulsatory intrusions of new magma and volatiles into an existing larger reservoir before the eruption occurred. Diffusion chronometry applied to orthopyroxene crystal rims shows that episodes of magma intrusion correlate temporally with recorded seismicity, providing evidence that some seismic events are related to magma intrusion. These time scales are commensurate with monitoring signals at restless volcanoes, thus improving our ability to forecast volcanic eruptions by using petrology. PMID:22628652

  20. Crustal heterogeneities beneath the 2011 Talala, Saurashtra earthquake, Gujarat, India source zone: Seismological evidence for neo-tectonics

    NASA Astrophysics Data System (ADS)

    Singh, A. P.; Mishra, O. P.; Rastogi, B. K.; Kumar, Santosh

    2013-01-01

    During the 1st decade of the 21st century, the study area of Talala, Saurashtra of western India witnessed three damaging earthquakes of moderate magnitude, year 2007 [Mw 5.0; Mw 4.8] and in the year 2011 [Mw 5.1] that generated public panic in the region. The last damaging moderate earthquake of the 20th October 2011 in Talala region (21.09°N;70.45°E), located at about 200 km south to the devastating 2001 Bhuj (23.412°N, 70.232°E) mainshock (Mw 7.6), jolted the entire Saurashtra region of Gujarat. A long series of aftershocks followed hereafter, recorded at nine seismograph/accelerograph stations. Hypocenters of aftershocks were relocated accurately using absolute and relative travel time (double-difference) method. In this study, we, for the first time, determined 3-D tomographic images of the upper crust beneath the 2011 Talala earthquake source zone by inverting about 1135 P and 1125 S wave arrival time data. Estimates of seismic velocities (Vp, Vs) and Poisson's ratio (σ) structures offer a reliable interpretation of crustal heterogeneities and their bearing on geneses of moderate earthquakes and their aftershock sequences beneath the source zone. It is found that the 2011 Talala mainshock hypocenter depth (6 km) is located near the boundary of the low and high velocity (Vp, Vs) and the source zone is associated with low-σ anomalies guarded by the prominent high-σ anomalies along the active fault zone having strike-slip motion beneath the earthquake source zone. The pattern of distribution of (Vp, Vs, σ) and its association with occurrences of aftershocks provide seismological evidence for the neo-tectonics in the region having left lateral strike-slip motion of the fault.

  1. The Seismic Tool-Kit (STK): an open source software for seismology and signal processing.

    NASA Astrophysics Data System (ADS)

    Reymond, Dominique

    2016-04-01

    We present an open source software project (GNU public license), named STK: Seismic ToolKit, that is dedicated mainly for seismology and signal processing. The STK project that started in 2007, is hosted by SourceForge.net, and count more than 19 500 downloads at the date of writing. The STK project is composed of two main branches: First, a graphical interface dedicated to signal processing (in the SAC format (SAC_ASCII and SAC_BIN): where the signal can be plotted, zoomed, filtered, integrated, derivated, ... etc. (a large variety of IFR and FIR filter is proposed). The estimation of spectral density of the signal are performed via the Fourier transform, with visualization of the Power Spectral Density (PSD) in linear or log scale, and also the evolutive time-frequency representation (or sonagram). The 3-components signals can be also processed for estimating their polarization properties, either for a given window, or either for evolutive windows along the time. This polarization analysis is useful for extracting the polarized noises, differentiating P waves, Rayleigh waves, Love waves, ... etc. Secondly, a panel of Utilities-Program are proposed for working in a terminal mode, with basic programs for computing azimuth and distance in spherical geometry, inter/auto-correlation, spectral density, time-frequency for an entire directory of signals, focal planes, and main components axis, radiation pattern of P waves, Polarization analysis of different waves (including noize), under/over-sampling the signals, cubic-spline smoothing, and linear/non linear regression analysis of data set. A MINimum library of Linear AlGebra (MIN-LINAG) is also provided for computing the main matrix process like: QR/QL decomposition, Cholesky solve of linear system, finding eigen value/eigen vectors, QR-solve/Eigen-solve of linear equations systems ... etc. STK is developed in C/C++, mainly under Linux OS, and it has been also partially implemented under MS-Windows. Usefull links: http

  2. THE ROLE OF ACTIVE REGION LOOP GEOMETRY. I. HOW CAN IT AFFECT CORONAL SEISMOLOGY?

    SciTech Connect

    Selwa, M.; Ofman, L.; Solanki, S. K. E-mail: leon.ofman@nasa.gov

    2011-01-01

    We present numerical results of coronal loop oscillation excitation using a three-dimensional (3D) MHD model of an idealized active region (AR) field. The AR is initialized as a potential dipole magnetic configuration with gravitationally stratified density and contains a loop with a higher density than its surroundings. We study different ways of excitation of vertical kink oscillations of this loop by velocity: as an initial condition, and as an impulsive excitation with a pulse of a given position, duration, and amplitude. We vary the geometry of the loop in the 3D MHD model and find that it affects both the period of oscillations and the synthetic observations (difference images) that we get from oscillations. Due to the overestimated effective length of the loop in the case of loops which have maximum separation between their legs above the footpoints (>50% of observed loops), the magnetic field obtained from coronal seismology can also be overestimated. The 3D MHD model shows how the accuracy of magnetic field strength determined from coronal seismology can be improved. We study the damping mechanism of the oscillations and find that vertical kink waves in 3D stratified geometry are damped mainly due to wave leakage in the horizontal direction.

  3. The Colombia Seismological Network

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  6. A Preliminary Study on Geological Structure and Seismological Activity in Fuxian Lake and Neighbouring Region

    NASA Astrophysics Data System (ADS)

    Tian, Jun; Lou, Ke

    2008-06-01

    The area around the Fuxian Lake is in the west branch of the Xiaojiang faulted zone, and is one of the regions with potential seismic activities. Destructive earthquakes with magnitudes larger than 5 (with intensity grade VI) happened in the region in history, and the region was affected many times by earthquakes with magnitudes larger than 6 occurring in neighbouring regions. From the analyses of geological structure of seismology and the characteristics of the seismic activities in recent years, the Fuxian Lake and the regions nearby are possible potential locations of epicenter for magnitude 7 to 7.5 earthquakes in the future. Therefore, according to the rules and regulations stipulated in "Anti Seismic and Natural Disaster Reduction Act", "Ordinance of Anti Seismic and Natural Disaster Reduction of Yuxi City", it is suggested that Yunnan Observatory should carry out evaluation of the seismic security in its construction of the Fuxian Lake Solar Observatory in accordance with the national technical standards decribed in "Technical Specifications for Evaluation of Seismic Security at Engineering Sites"

  7. MHD seismology as a tool to diagnose the coronae of X-ray active sun-like flaring stars

    NASA Astrophysics Data System (ADS)

    Srivastava, A. K.; Lalitha, Sairam

    It is now well accepted that the detection of impulsively generated multiple MHD modes are potentially used in diagnosing the local plasma conditions of the solar corona. Analogously, such analyses can also be significantly used in diagnosing the coronae of X-ray active Sun-like stars. In the present paper, we briefly review the detection of MHD modes in coronae of some X-ray active Sun-like stars, e.g. Proxima Centauri, ξ-Boo etc using XMM-Newton observations, and discuss the implications in deriving physical information about their localized magnetic atmosphere. We conclude that the refinement in the MHD seismology of solar corona is also providing the best analogy to develop the stellar seismology of magnetically active and flaring Sun-like stars to deduce the local physical conditions of their coronae.

  8. Forensic seismology

    USGS Publications Warehouse

    Thirlaway, H. I. S.

    1979-01-01

    Twenty years ago, politicians, concerned a the slow progress of negotiations to stop nuclear weapons testing, described the state of seismology as being in the equivalent of the Stone Age. this assessment spurred the beginning of research and development at the Atomic Weapons Research Establishment near the village of Aldermaston, England. the object was to establish the limits of seismology for the detection and identification of underground explosions against a background of earthquakes. Thereby, verification that there was compliance with a treaty to ban further nuclear tests could be assessed before making political decisions. Negotiations now taking place in Geneva between the Soviet Union, the United States, and the United Kingdom are aimed at such a treaty.  

  9. Combined Active and Passive Seismology to Study Continental Collision; Central South Island of New Zealand

    NASA Astrophysics Data System (ADS)

    Stern, T.; Okaya, D.; Baldock, G.; Scherwath, M.

    2005-12-01

    Central South Island of New Zealand is a continental region that has undergone both collision and strike-slip shear in the late Tertiary. From a tectonics, or rock-mechanics, view-point there is an interest in how the crust and mantle have been both thickened and sheared. The South Island Geophysical Transect (SIGHT) and the Southern Alps Passive Seismic Experiment (SAPSE) - both jointly funded US-NZ programs - studied these processes. Some of the most important findings came about by merging data from passive and active seismology. Three specific examples will be discussed: 1. Teleseismic P-wave delays from earthquakes in the Western Pacific are used to map a ~ 0.8-1 s speed-up in the mantle right beneath the region of thickest crust and highest topography of the collision zone. Forward modeling of this velocity anomaly shows that the amplitude of the anomaly can be explained by a 100 km-thick body that has a 7% in increase in P-wave speed. From the spatial pattern of the P-wave residuals we can also show that the high-speed body is about 80-100 km wide and roughly vertically disposed beneath the crustal root. The shape and position of the high-speed body beneath the seismically determined crustal root is consistent with it being thickened, and therefore cold, mantle lithosphere that has uniformly strained into a roughly symmetric root beneath the collision zone. 2. Pn anisotropy measurements from our onshore-offshore seismic shooting program allowed us to make mutually perpendicular determinations of Pn wave speeds at three localities. P-wave anisotropies of up to 11 ± 3%, 6.5 ± 2.5% and 0 ± 3%, were measured, depending on the distance of the measurement from the surface trace of the plate boundary (the Alpine Fault). These are necessarily minimum anisotropy values because it assumes that the two axes of measurement are those of minimum and maximum wave speed. Combining these results with SKS splitting values of ~ 2 s from passive seismology allowed us to make

  10. Planetary Seismology

    NASA Technical Reports Server (NTRS)

    Weber, Renee C.

    2015-01-01

    Of the many geophysical means that can be used to probe a planet's interior, seismology remains the most direct. In addition to Earth, seismometers have been installed on Venus, Mars, and the Moon. Given that the seismic data gathered on the Moon (now over 40 years ago) revolutionized our understanding of the Moon and are still being used today to produce new insight into the state of the lunar interior, it is no wonder that many future missions, both real and conceptual, plan to take seismometers to other planets. To best facilitate the return of high-quality data from these instruments, as well as to further our understanding of the dynamic processes that modify a planet's interior, various modeling approaches are used to quantify parameters such as the amount and distribution of seismicity, tidal deformation, and seismic structure of the terrestrial planets. In addition, recent advances in wavefield modeling have permitted a renewed look at seismic energy transmission and the effects of attenuation and scattering, as well as the presence and effect of a core, on recorded seismograms. In this talk I will discuss some of these methods and review the history of planetary seismology.

  11. Web Based Seismological Monitoring (wbsm)

    NASA Astrophysics Data System (ADS)

    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

  12. Citizen Seismology

    NASA Astrophysics Data System (ADS)

    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

  13. Fault slip source models for the 2014 Mw 6.9 Samothraki-Gökçeada earthquake (North Aegean Trough) combining geodetic and seismological observations

    NASA Astrophysics Data System (ADS)

    Saltogianni, Vasso; Gianniou, Michail; Taymaz, Tuncay; Yolsal-ćevikbilen, Seda; Stiros, Stathis

    2015-12-01

    The 24 May 2014, Mw 6.9, Samothraki-Gökçeada shallow (depth: 11 km) earthquake along the North Aegean Trough (NAT), at the westward extension of the North Anatolian Fault Zone (NAFZ), is investigated using constraints from seismological and geodetic data. A point source solution based on teleseismic long-period P and SH waveforms suggests an essentially strike-slip faulting mechanism consisting of two subevents, while from a finite fault inversion of broadband data the rupture area and slip history were estimated. Analysis of data from 11 permanent GPS stations indicated significant coseismic horizontal displacement but no significant vertical or postseismic slip. Okada-type inversion of horizontal slip vectors, using the new TOPological INVersion algorithm, allowed precise modeling of the fault rupture both as single and preferably as double strike-slip faulting reaching the surface. Variable slip models were also computed. The independent seismological and geodetic fault rupture models are broadly consistent with each other and with structural and seismological data and indicate reactivation of two adjacent fault segments separated by a bend of the NAT. The 2014 earthquake was associated with remote clusters of low-magnitude aftershocks, produced low accelerations, and filled a gap in seismicity along the NAT in the last 50 years; faulting in the NAT seems not directly related to the sequence of recent faulting farther east, along the NAFZ and the seismic gap in the Marmara Sea near Istanbul.

  14. Integrated analysis of seismological, gravimetric and structural data for identification of active faults geometries in Abruzzo and Molise areas (Italy)

    NASA Astrophysics Data System (ADS)

    Gaudiosi, Germana; Nappi, Rosa; Alessio, Giuliana; Porfido, Sabina; Cella, Federico; Fedi, Maurizio; Florio, Giovanni

    2015-04-01

    This paper deals with an interdisciplinary research that has been carried out for more constraining the active faults and their geometry of Abruzzo - Molise areas (Central-Southern Apennines), two of the most active areas from a geodynamic point of view of the Italian Apennines, characterized by the occurrence of intense and widely spread seismic activity. An integrated analysis of structural, seismic and gravimetric (Gaudiosi et al., 2012) data of the area has been carried out through the Geographic Information System (GIS) which has provided the capability for storing and managing large amount of spatial data from different sources. In particular, the analysis has consisted of these main steps: (a) collection and acquisition of aerial photos, numeric cartography, Digital Terrain Model (DTM) data, geophysical data; (b) generation of the vector cartographic database and alpha-numerical data; c) image processing and features classification; d) cartographic restitution and multi-layers representation. In detail three thematic data sets have been generated "fault", "earthquake" and "gravimetric" data sets. The fault Dataset has been compiled by examining and merging the available structural maps, and many recent geological and geophysical papers of literature. The earthquake Dataset has been implemented collecting seismic data by the available historical and instrumental Catalogues and new precise earthquake locations for better constraining existence and activity of some outcropping and buried tectonic structures. Seismic data have been standardized in the same format into the GIS and merged in a final catalogue. For the gravimetric Dataset, the Multiscale Derivative Analysis (MDA) of the gravity field of the area has been performed, relying on the good resolution properties of the Enhanced Horizontal Derivative (EHD) (Fedi et al., 2005). MDA of gravity data has allowed localization of several trends identifying anomaly sources whose presence was not previously

  15. Map, Excite, Jump, and Measure: An Outreach Activity That Utilizes Seismology to Engage Students in Technology, Science, Engineering, and Mathematics

    NASA Astrophysics Data System (ADS)

    van der Lee, S.; Tekverk, K.; Rooney, K.; Boxerman, J.

    2013-12-01

    We designed and will present a lesson plan to teach students STEM concepts through seismology. The plan addresses new generation science standards in the Framework for K-12 Science Education as well AAAS Benchmarks for Science Literacy. The plan can be executed at a facility with a seismometer in a research facility or university, on a field trip, but it can also be used in a school setting with a school seismometer. Within the lesson plan, the students first use technology to obtain earthquake location data and map them. Next, the students learn about the science of earthquakes, which is followed by an engineering activity in which the students design a hypothetical seismometer and interact with the actual seismometer and live data display. Lastly the students use mathematics to locate an earthquake through trilateration. The lesson plan has been fine-tuned through implementation with over 150 students from grades 3-12 from the Chicago area.

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

    NASA Astrophysics Data System (ADS)

    Haslinger, Florian; EPOS Seismology Consortium, the

    2015-04-01

    collection and dissemination mechanisms, as well as improving historical earthquake data services; - the development of a comprehensive suite of earthquake hazard products, tools, and services harmonized on the European level and available through a common access platform, encompassing information on seismic sources, seismogenic faults, ground-motion prediction equations, geotechnical information, and strong-motion recordings in buildings, together with an interface to earthquake risk; - a portal implementation of computational seismology tools and services, specifically for seismic waveform propagation in complex 3D media following the results of the VERCE project, and initiating the inclusion of further suitable codes on that portal in discussion with the community, forming the basis of EPOS computational earth science infrastructure. Important features common to all tasks are the development of EPOS-wide integrated and interoperable metadata structures, the introduction and utilization of adequate and referencable persistent identifiers for data and products, and the implementation of appropriate user access and authorization mechanisms. Here we present further details on the technical work plan for Seismology during the EPOS Implementation Phase and its integration into the overall EPOS build-up, together with the current view and state of the discussion on the development of adequate governance structures, and discuss how we envision the interaction with and involvement of the wider community outside the consortium in these activities.

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

    USGS Publications Warehouse

    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

  18. Seismology and the Wounded Sun

    NASA Astrophysics Data System (ADS)

    Cally, Paul

    2016-05-01

    Active regions provide an opening in the Sun's surface that allow seismic waves to penetrate the overlying atmosphere. Some proportion then return due to reflection, with implications for "internal" seismology. This is illustrated using simulations with particular reference to "travel times" and acoustic halos.

  19. Powerful low-frequency vibrators and outlooks of their application at monitoring of engineering constructions and at solving other problems of active seismology

    SciTech Connect

    Alekseev, A. S.; Chichinin, I. S.; Korneev, V. A.; Komissarov, V. V.; Seleznev, V. S.; Emanov, A. F.

    2004-06-11

    In the past two decades, active seismology studies in Russia have made use of powerful (40- and 100-ton) low-frequency vibrators. These sources create a force amplitude of up to 100 tons and function in the 1.5-3, 3-6 and 5-10 Hz frequency bands. The mobile versions of the vibrator have a force amplitude of 40 tons and a 6-12 Hz frequency band. Registration distances for the 100 ton vibrator are as large as 350 km, enabling the refracted waves to penetrate down to 50 km depths. Vibrator operation sessions are highly repeatable, having distinct ''summer'' or ''winter'' spectral patterns. A long profile of seismic records allows estimating of fault zone depths using changes in recorded spectra. Other applications include deep seismic profiling, seismic hazard mapping, structural testing, stress induced anisotropy studies, seismic station calibration, and large-structure integrity testing. In more detail, these questions are discussed in reports of our colleagues from Novosibirsk. This report is devoted mainly to powerful low-frequency vibrators, their theoretical description and design. Besides, problems of vibroseismic monitoring of engineering constructions are briefly elucidated.

  20. Seismology in Chile

    USGS Publications Warehouse

    Kausel, E.

    1983-01-01

    The Department of Geology and Geophysics, which is under the faculties of Mathematics and Physical Sciences of the University of Chile, is the organization that is responsible for the Seismological Service of Chile and for installing,operating, and maintaining the seismological stations as well as all the strong-motion stations in Chile.

  1. Identification of active faults in Abruzzo area (central Italy) through the analysis of geological, seismological and gravimetric data

    NASA Astrophysics Data System (ADS)

    Luiso, Paola; Paoletti, Valeria; Gaudiosi, Germana; Nappi, Rosa; Cella, Federico; Fedi, Maurizio

    2016-04-01

    Identification of active faults in abruzzo area (central italy) through the analysis of geological, seismological and gravimetric data The aim of this study is to identify and constrain the geometry of the seismogenic structures (active, outcropping and buried fault systems) of the Abruzzo area (central Italy), through an integrated analysis of geo-structural, seismic and gravimetric data. We generated three thematic: "faults", "earthquakes" and "gravimetric" data: i) The fault dataset consists of data extracted from the available structural and geological maps (ITHACA catalogue; the "Neotectonic Map of Italy" 1:500.000; several geological sheets 1:50.000 from ISPRA CARG project; the Geological Map 1:100.000 Sheet 1), and many geological studies. ii) The earthquakes datasets was created by merging the data from historical and instrumental Catalogues (CPTI04 and CPTI11; ISIDE - INGV). iii) The gravimetric datasets consists in the Multiscale Derivative Analysis (MDA) of the Bouguer anomaly map of the area, whose maxima show the presence of density lineaments. The merge of these datasets in GIS environment, highlighted four possible scenarios of correlation between faults, earthquakes and MDA maxima: 1) the existence of active faults, revealed by a strong correlation between epicentral location of seismic clusters, fault positions and MDA maxima; 2) the existence of buried active faults, highlighted by a good correlation between MDA maxima and epicentral positions, without correspondence with faults known from geological data; 3) the existence of inactive or silent faults, detected by the presence of faults reported in the geological datasets and literature which are associated with MDA maxima, without correlation of earthquakes; 4) the existence of faults not correlated with MDA maxima; this could be due to faults putting in contact two lithologies with a similar density. A comparison between seismic hypocentral locations and the fault geometry retrieved by DEXP

  2. Disturbances of the VLF/LF radio signal reception at Dobrogea Seismological Observatory due to local abnormal electric activity

    NASA Astrophysics Data System (ADS)

    Moldovan, Iren-Adelina; Toader, Victorin; Dolea, Paul; Biagi, Pier Francesco

    2015-04-01

    The National Institute for Earth Physics, as part of the INFREP initiative, has monitored radio waves emitted by 10 transmitters all over Europe in relation with seismicity in the last 5 years. In Romania a radio receiving system is located in only one site (Dobrogea Seismological Observatory) situated in Eforie Nord, in the Eastern part of Romania. The electro-magnetic field monitored both at the ground and (sub) ionospheric level, in different frequency ranges (VLF/LF) is considered to be promising for earthquake forecasting. Because the abnormal behavior of the VLF/LF recordings that could not be correlated with the tectonic activity of the seismogenic zones crossed by the radio paths, we decided to monitor other two parameters, at the receiving site: the vertical component of the atmospheric electric field, which indicates variations of electrical properties of the near-ground air (Boltek electric field mill), and the atmospheric local conditions (WS-3600 weather station). The zone is also surveyed by seismic devices (seismometers, accelerometers and infrasonic equipment) and GPS/GNSS base stations to emphasize the local tectonic conditions. We obtained in such way a multiple-parameter monitoring system that increases the confidence in observational data and decreases uncertainties regarding the accuracy of the data recorded until now. As we are exploring different parameters we have obtained some conclusions regarding the correlation of the anomalies with their possible causes. The final expectation of the monitoring system regard the chance to take a snapshot of the geophysical medium before, during and after a significant earthquake occurrence and to reveal if there was or wasn't a noticeable trace of the preparatory stage of it. This work was partially supported by a grant of the Romanian National Authority for Scientific Research, Programe for research- Space Technology and Avanced Research - STAR, project number 84/2013, and by the NUCLEU project, PN 09

  3. Forensic seismology revisited

    NASA Astrophysics Data System (ADS)

    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 < 4.5) and there are exceptions—earthquakes that look like explosions. A difficulty with identification criteria developed in the early days of forensic seismology was that they were in the main empirical—it was not known why they appeared to work and if there were test sites or earthquakes where they would 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

  4. Mantle heterogeneities within active margins of the world oceans and their seismological characteristics

    NASA Astrophysics Data System (ADS)

    Boldyrev, S. A.

    1985-03-01

    The principal geotectonic element of active marginal areas is represented by arcuate structures characterized by two mantle volumes in contact containing materials with different properties. The rigid, high-density, and comparatively cold region with concentrated earthquake hypocentres is accompanied by an aseismic mantle where a low-velocity layer at depths from 150 to 250 km and a low-velocity zone under the present volcanoes form a specific volume. P-wave velocity of the latter is nearly 15% below the standard values and nearly 20% lower than that in the adjacent seismically active blocks. As a result of these lateral changes in the physical properties, there appears to exist a considerable gradient of lithostatic pressure whose maximum occurs in the focal zone and its resulting forces point to the arc centre, thus determining the horizontal displacement of sinking high-density matter with the focal zone. Velocity changes of the aseismic mantle block along the geostructure are determined by the geological evolution of the region and reflected in its morphostructure. In shallow parts of the northern Sea of Okhotsk and western Kamchatka with continenetal type of crust developed on the bottom of the pre-Mesozoic platform, the P-wave velocities in the upper mantle are 0.5-0.6 km/s smaller than those under the Kuril abyssal plain with suboceanic crust. Small-scale mantle inhomogeneities of the focal zone manifest themselves in a seismic anisotropy which changes both in magnitude and direction. It reflects a reaction of the medium to the shearing stresses and is controlled by strength anisotropy. Distribution of seismic parameters, velocity and attenuation of elastic waves in the mantle of active margins is represented by alternating areas of high and low strength. Weaker areas coincide both in setting and trend with deep-seated faults which cut across the arcuate geofeatures. This combination of arcuate and orthogonal tectonic systems in the northwestern Pacific

  5. Seismology and space-based geodesy

    NASA Technical Reports Server (NTRS)

    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.

  6. EPOS: Integrating seismological Research Infrastructures within Europe

    NASA Astrophysics Data System (ADS)

    Eck Van, Torild; Clinton, John; Haslinger, Florian; Michelini, Alberto

    2013-04-01

    itself, it is important to harvest relevant ideas and tools from other scientific communities dealing with similar issues. We will present a short summary of those developments and how they fit within the proposed visions and concepts. These integration developments address a wide framework of seismological services that include: basic seismological data services (waveform data from velocity and acceleration sensors from land and underwater sites); seismological data products (source mechanism and process estimates, earthquake catalogues, structural and tomography model estimations); seismological models (synthetic waveforms, earth and earthquake source models, hazard models).Our aim is to build significantlyimproved seismological services and valuable products for multidisciplinary earth science research.

  7. Computational aspects of seismology

    NASA Astrophysics Data System (ADS)

    Koper, Keith David

    Recent increases in computer speed and memory have opened the door to new analytical techniques in seismology. This dissertation focuses on the application of two such techniques: finite difference simulation of wave propagation in complex media, and genetic algorithm (GA) based searching for solutions to inverse problems. The first two chapters detail the use of a 3D finite difference algorithm in modeling the P- and S-wave velocity structure of the Tonga subduction zone. The large memory capacity of modern computers permits the use of a fine spatial grid, allowing for the accurate comparison of subtly varying velocity models. I contrast the theoretical traveltimes to local data that were recorded by two temporary deployments of broadband, land stations and ocean bottom seismometers. The primary results from these studies are: (1) it is not possible to distinguish between equilibrium and metastable models of subduction with travel time data, and (2) the same mechanism accounts for the fast, slab velocity anomaly and the slow, backarc velocity anomaly under the Lau spreading center---both are consistent with temperature perturbations, indicating that the role of partial melt is insignificant. The third and fourth chapters concern the application of GAs to two kinds of seismological inverse problems. The relatively fast speed of present day CPUs allows global search methods, such as GAs, to be feasible on realistic problems. In the third chapter I compare the performance of a GA based search with those of a series of more traditional, local descent methods on the problem of inverting PKP travel times for radial, P-wave models of the Earth's core and lowermost mantle. Even though both the model parametrization and dataset are heavily smoothed, there exist significant complexities in the error landscape (due to nonlinearities in the forward calculation) that render the GA method superior. In the fourth chapter I present a variant of a traditional GA, known as a

  8. A tale of ambiguities and interpretation pitfalls: seismology based source models for the Bárðarbunga caldera collapse earthquakes, Iceland

    NASA Astrophysics Data System (ADS)

    Heimann, Sebastian; Cesca, Simone; Hensch, Martin; Dahm, Torsten; Hjörleifsdóttir, Vala

    2016-04-01

    The 2014-2015 collapse of the Bárðarbunga caldera was accompanied by a notable seismic sequence of more than 80 events with Mw >= 4.5. We analyse these earthquakes using broadband recordings from the Icelandic regional seismic network using standard and probabilistic centroid moment tensor inversion. Our results reveal that the centroids of the events cluster beneath the northern and southern caldera rims and are characterized by the superposition of a near-vertical negative compensated linear vector dipole (CLVD) and shear faulting of different orientations. It is well known that moment tensor decompositions are non-unique. We demonstrate that in this particular case, applying the standard moment tensor decomposition scheme would lead to wrong conclusions, incompatible with independent observations like the fault orientations at the caldera rims. We propose an alternative decomposition scheme which is well compatible with the observations. Furthermore, we propose a simple mechanical model for asymmetric, drainage-driven caldera collapses, capable of explaining the seismological observations at regional distances: an initial failure along a steep fault is followed by a deformation response of a deeper magmatic source. The shear faulting contribution occurs either as thrust faulting along an outward dipping fault (northern rim) or as normal faulting along an inward dipping fault (southern rim). As a side note, we discuss the parameter trade-offs in our full and deviatoric centroid moment tensor inversion problems and show how to rigorously quantify uncertainties on the results.

  9. Seismology Outreach in Alaska

    NASA Astrophysics Data System (ADS)

    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.

  10. The seismology of geothermal regimes. Final report

    SciTech Connect

    Aki, K.

    1997-04-01

    The authors have been developing seismological interpretation theory and methods applicable to complex structures encountered in geothermal areas for a better understanding of the earth`s geothermal regimes. The questions the y have addressed in their research may be summarized as ``What is going on in the earth`s crust under tectonically active regions; what are the structures and processes responsible for such activities as earthquakes and volcanic eruptions; and how can one capture their essence effectively by means of seismological studies?`` First, the authors found clear evidence for localization of scattered seismic energy in the deep magmatic system of the volcano on the island of Reunion in the Indian Ocean. The seismic coda of local earthquakes show concentrated energy in the intrusive zones as late as 30 to 40 seconds after the origin time. This offers a very effective method for defining a zone of strong heterogeneity on a regional scale, complementary to the high resolution study using trapped modes as pursued in the past project. Secondly, the authors identified about 700 long-period events with various frequencies and durations from the data collected during the past 5 years which included three episodes of eruption. They are applying a finite-element method to the simplest event with the longest period and the shortest duration in order to find the location, geometry and physical properties of their source deterministically. The preliminary result described here suggests that their sources may be a horizontally lying magma-filled crack at a shallow depth under the summit area. In addition to the above work on the Reunion data, they have continued the theoretical and observational studies of attenuation and scattering of seismic waves.

  11. A new crustal model of the western Alpine region derived by combining controlled-source seismology and local earthquake tomography data

    NASA Astrophysics Data System (ADS)

    Wagner, M.; Kissling, E.; Husen, S.

    2012-04-01

    We present a newly developed approach of combining controlled-source seismology (CSS) and local earthquake tomography (LET) data to obtain a new 3D crustal model in the western Alpine region. Our approach takes into account the strengths of each seismic method and the quality of each individual seismic information. Therefore, our western Alpine 3D model includes a well-defined Moho, constrained by CSS and LET data, as well as smooth lateral variations in seismic velocities. The consistent combination of results from two different seismic methods is feasible due to the definition of LET Moho elements and their uncertainty estimates. Identification of LET Moho elements is based on a characteristic P-wave velocity (7.25 km/s); uncertainty estimates are derived from the diagonal element of the resolution matrix (RDE), absolute P-wave velocities that are typical for crust and mantle, and a specific velocity gradient around Moho depth. We validate our approach by comparing highest quality Moho elements from both methods coinciding in 353 localities. We find only four Moho elements for which the difference in Moho depth is greater than the error sum of the uncertainty estimates and these four Moho elements are all located close to plate boundaries, where 3D migration of CSS reflector elements is poorly constrained. Our model clearly shows three Moho surfaces, being Europe, Adria, and Liguria, as well as major tectonic structures like suture zones and the high-velocity Ivrea body. Compared to previous studies, our model allows for a more accurate definition of plate boundaries at Moho level. We attribute this to the larger number of available Moho elements derived from LET data. Therefore, the new model allows better insights in the deep crustal structure of the Alpine collision zone.

  12. Foundations of Statistical Seismology

    NASA Astrophysics Data System (ADS)

    Vere-Jones, David

    2010-06-01

    A brief account is given of the principles of stochastic modelling in seismology, with special regard to the role and development of stochastic models for seismicity. Stochastic models are seen as arising in a hierarchy of roles in seismology, as in other scientific disciplines. At their simplest, they provide a convenient descriptive tool for summarizing data patterns; in engineering and other applications, they provide a practical way of bridging the gap between the detailed modelling of a complex system, and the need to fit models to limited data; at the most fundamental level they arise as a basic component in the modelling of earthquake phenomena, analogous to that of stochastic models in statistical mechanics or turbulence theory. As an emerging subdiscipline, statistical seismology includes elements of all of these. The scope for the development of stochastic models depends crucially on the quantity and quality of the available data. The availability of extensive, high-quality catalogues and other relevant data lies behind the recent explosion of interest in statistical seismology. At just such a stage, it seems important to review the underlying principles on which statistical modelling is based, and that is the main purpose of the present paper.

  13. Seismology in Japan in 1939-1947

    USGS Publications Warehouse

    Kawasumi, Hirosi

    1950-01-01

    In the latter half of this period the seismology in Japan was so much affected by the war that retrogressions in the instrumental seismology became very remarkable. Much regretted three leading seismologists, professors Ishimoto, Sezawa, and Inamura died in this period. But the seismic activities in this well-known land of earthquakes were not less active than usual as will be seen in the annexed table of destructive earthquakes. Seismologists in this country are now endeavoring to restore its former prosperity in this bitter circumstance.

  14. High-performance computing in seismology

    SciTech Connect

    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.

  15. Integrated Seismological Network of Brazil: Key developments in technology.

    NASA Astrophysics Data System (ADS)

    Pirchiner, Marlon; Assumpção, Marcelo; Ferreira, Joaquim; França, George

    2010-05-01

    The Integrated Seismological Network of Brazil - BRASIS - will integrate the main Brazilian seismology groups in an extensive permanent broadband network with a (near) real-time acquisition system and automatic preliminary processing of epicenters and magnitudes. About 60 stations will cover the whole country to continuously monitor the seismic activity. Most stations will be operating by the end of 2010. Data will be received from remote stations at each research group and redistributed to all other groups. In addition to issuing a national catalog of earthquakes, each institution will make its own analysis and issue their own bulletins taking into account local and regional lithospheric structure. We chose the SEED format, seedlink and SeisComP as standard data format, exchange protocol and software framework for the network management, respectively. All different existing equipment (eg, Guralp/Scream, Geotech/CD1.1, RefTek/RTP, Quanterra/seedlink) will be integrated into the same system. We plan to provide: 1) improved station management through remote control, and indexes for quality control of acquired data, sending alerts to operators in critical cases. 2) automatic processing: picking, location with local and regional models and determination of magnitudes, issuing newsletters and alerts. 3) maintainence of an earthquakes catalog, and a waveforms database. 4) query tools and access to metadata, catalogs and waveform available to all researchers. In addition, the catalog of earthquakes and other seismological data will be available as layers in a Spatial Data Infrastructure with open source standards, providing new analysis capabilities to all geoscientists. Seiscomp3 has already been installed in two centers (UFRN and USP) with successful tests of Q330, Guralp, RefTek and Geotech plug-ins to the seedlink protocol. We will discuss the main difficulties of our project and the solutions adopted to improve the Brazilian seismological infrastructure.

  16. Ionospheric seismology: The last step before true contributions to seismology?

    NASA Astrophysics Data System (ADS)

    Lognonne, P. H.; Rakoto, V.; Khelfi, K.; Rolland, L.; Astafyeva, E.; Occhipinti, G.; Coisson, P.; Drilleau, M.; Makela, J. J.; Walwer, D.

    2015-12-01

    Ionospheric seismology, which was at most seen as an exotic way to record doubtful signals in the early 2000 has gain maturity, especially after the worldwide observations made during the Tohoku 2011 earthquake and tsunami. The last steps for important contributions in seismology will request however these data to be modeled and inverted in a way precise enough for new and original constraints on the seismic sources, amplitude of tsunamis and atmospheric/interior seismic/acoustic velocities profiles. Ionospheric observations are now able to provide time depending maps of the ionospheric waves, enabling the location of the sources, measurement of the wave speed and amplitude, for both acoustic waves above or close the epicenter or remotely observed Rayleigh and Tsunami waves. Are these data good enough for inversions? Are the modelling techniques good enought for inversions? We therefore first compare and illustrate the different observation techniques: ground, air-based and space-based GPS and airglow, focusing on the Tohoku 2011 and Haida Gwai earthquake and tsunamis, discuss the physics enabling the conversion of seismic waves into electron perturbation (for GPS data) and light emission (for airglow) and signal to noise issues. Comparison between data and waveforms modelling are then shown by using either Normal Mode summations for remote detections or Spectral Element techniques for local detections, with an emphasis in the later case on non-linear effects and TEC post-seismic depletions. A special attention is made on the sensitivity of the waveforms to the various parameters of the models, including the sensitivity of the conversion of the seismic to atmospheric signals with the atmosphere structure, the crust subsurface and the ocean thickness and the sensitivity of the conversion of the atmospheric to ionospheric signal with respect to local time, ionospheric state and magnetic latitude. We then present the perspectives in term of inversion for both the

  17. Forensic seismology revisited

    NASA Astrophysics Data System (ADS)

    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 < 4.5) and there are exceptions—earthquakes that look like explosions. A difficulty with identification criteria developed in the early days of forensic seismology was that they were in the main empirical—it was not known why they appeared to work and if there were test sites or earthquakes where they would 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

  18. Planetary seismology and interiors

    NASA Technical Reports Server (NTRS)

    Toksoz, M. N.

    1979-01-01

    This report briefly summarizes knowledge gained in the area of planetary seismology in the period 1969-1979. Attention is given to the seismic instruments, the seismic environment (noise, characteristics of seismic wave propagation, etc.), and the seismicity of the moon and Mars as determined by the Apollo missions and Viking Lander experiments, respectively. The models of internal structures of the terrestrial planets are discussed, with the earth used for reference.

  19. Discrimination between induced, triggered, and natural earthquakes close to hydrocarbon reservoirs: A probabilistic approach based on the modeling of depletion-induced stress changes and seismological source parameters

    NASA Astrophysics Data System (ADS)

    Dahm, Torsten; Cesca, Simone; Hainzl, Sebastian; Braun, Thomas; Krüger, Frank

    2015-04-01

    Earthquakes occurring close to hydrocarbon fields under production are often under critical view of being induced or triggered. However, clear and testable rules to discriminate the different events have rarely been developed and tested. The unresolved scientific problem may lead to lengthy public disputes with unpredictable impact on the local acceptance of the exploitation and field operations. We propose a quantitative approach to discriminate induced, triggered, and natural earthquakes, which is based on testable input parameters. Maxima of occurrence probabilities are compared for the cases under question, and a single probability of being triggered or induced is reported. The uncertainties of earthquake location and other input parameters are considered in terms of the integration over probability density functions. The probability that events have been human triggered/induced is derived from the modeling of Coulomb stress changes and a rate and state-dependent seismicity model. In our case a 3-D boundary element method has been adapted for the nuclei of strain approach to estimate the stress changes outside the reservoir, which are related to pore pressure changes in the field formation. The predicted rate of natural earthquakes is either derived from the background seismicity or, in case of rare events, from an estimate of the tectonic stress rate. Instrumentally derived seismological information on the event location, source mechanism, and the size of the rupture plane is of advantage for the method. If the rupture plane has been estimated, the discrimination between induced or only triggered events is theoretically possible if probability functions are convolved with a rupture fault filter. We apply the approach to three recent main shock events: (1) the Mw 4.3 Ekofisk 2001, North Sea, earthquake close to the Ekofisk oil field; (2) the Mw 4.4 Rotenburg 2004, Northern Germany, earthquake in the vicinity of the Söhlingen gas field; and (3) the Mw 6

  20. Albuquerque Seismological Laboratory--50 years of global seismology

    USGS Publications Warehouse

    Hutt, C.R.; Peterson, Jon; Gee, Lind; Derr, John; Ringler, Adam; Wilson, David

    2011-01-01

    The U.S. Geological Survey Albuquerque Seismological Laboratory is about 15 miles southeast of Albuquerque on the Pueblo of Isleta, adjacent to Kirtland Air Force Base. The Albuquerque Seismological Laboratory supports the Global Seismographic Network Program and the Advanced National Seismic System through the installation, operation, and maintenance of seismic stations around the world and serves as the premier seismological instrumentation test facility for the U.S. Government.

  1. Supporting Ice Seismology

    NASA Astrophysics Data System (ADS)

    Parker, T.; Beaudoin, B. C.; Fowler, J. C.

    2010-12-01

    Climate change research, and glaciology in particular, has increasingly embraced seismology in recent years. The NSF supported IRIS/PASSCAL Instrument Center is working with researchers to develop the unique instruments and techniques for collecting data in this challenging environment. Global concern with sea level change along with strategic interests of the US government and other nations is driving a large investment in glaciological climate research. A number of groups have demonstrated new seismologically-derived constraints on glaciological conditions and processes. Environmental challenges include remote and precarious locations, necessitating robust yet quickly deployable seismic stations and long periods of autonomous operation. Temperature extremes and the possibility of immersion from large annual snow loads, resulting in a deployment surface that can vary from 50 feet of snow cover to bare ice with large melt pools in a single season are additional major challenges. There is also an urgency created by studies indicating that the high latitude continental ice sheets are metastable and that behavior is changing now. Scientists are presently commonly utilizing adaptations of available instrumentation designed for low latitude and milder field conditions as appropriate, but seek better, more capable, and more flexible solutions, including integration of environmental sensors and real-time data telemetry and station control as some of these experiments evolve into a monitoring effort. Seismic instrumentation is only produced by a small number of companies and, innovation for new instruments takes time and requires substantial investment. While pursuing longer-term innovation funding strategies, we are also adapting current instrumentation paradigms to glaciological use (e.g., by leveraging the cold instrument development for research in Antarctica during the IPY). We are also encouraging industrial partners to respond to these demands and challenges with

  2. Forensic Seismology and Nuclear Explosion Monitoring

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.; Wallace, T.

    2002-12-01

    Forensic seismology was first termed by H.I.S. Thirlaway in the late 1950s to describe what is now known as verification seismology. In nuclear monitoring it is often the study of anomalous events that for some reason caused an operational system to break down. Examples of events that have elicited study include abnormal mining explosions, mine collapse and rockbursts, earthquakes near nuclear test sites and anomalous nuclear explosions. Analysis of these anomalous disturbances has been the key to understanding source physics. This information in turn, has improved our understanding of the physical basis of seismic event identification, yield estimation, and evasion scenarios. In this talk, we will review examples of anomalous disturbances from different types of sources and how the subsequent analysis led to an improved understanding the effect of source phenomenology on nuclear explosion monitoring.

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

    NASA Astrophysics Data System (ADS)

    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

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

    SciTech Connect

    Abdelwahed, Mohamed F.

    2012-09-26

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  6. Review of active faults in the Borborema Province, Intraplate South America — Integration of seismological and paleoseismological data

    NASA Astrophysics Data System (ADS)

    Bezerra, Francisco H. R.; do Nascimento, Aderson F.; Ferreira, Joaquim M.; Nogueira, Francisco C.; Fuck, Reinhardt A.; Neves, Benjamim B. Brito; Sousa, Maria O. L.

    2011-10-01

    In this paper, we provide a review of the properties and behavior of active faults in the Borborema Province, northeastern Brazil, using instrumental, historical and paleoseismological records. The Borborema Province is one of the most seismically active parts of the South American stable continental region (the South American Platform). The Province encompasses an area ~ 900 km long and ~ 600 km wide. It is composed of a branching system of Neoproterozoic orogens, encompassing Archean and Proterozoic inliers deformed during the Brasiliano orogeny at ~ 750-500 Ma. Active faults reactivate shear zones or regional foliation and quartz veins or cut across the preexisting fabric. Active faults are usually strike-slip and generate events ≤ 5.2 m b, which we interpret as the lower limit for maximum possible earthquakes. Seismicity is concentrated in the upper crust down to a depth of 12 km. Earthquake sequences illuminated naturally occurring faults up to 40 km long and segments in the order of 0.5-2.6 km in faults related to induced seismicity. Earthquakes have a recurrence interval of ~ 15 years for M s = 4. Paleoseismological data indicate that although earthquakes associated with surface ruptures have not occurred in the last 200 years, they struck the region in the last ~ 100 ka. Paleoearthquakes have a recurrence interval of ~ 15.8 ka for magnitudes of ~ 5.5 M w in individual faults. Moreover, earthquake-induced soft-sediment deformation caused by events of at least 5.5-6.0 M s have occurred at least six times in the last 400-10 ka in one alluvial valley. Seismically defined faults are concentrated along the continental margin at the border of sedimentary basins as far as 250-300 km inland in areas of extended crust; faults in the paleoseismic record are also found in rift basins along this margin. Both records also reveal that active faults tend to be hydraulically conductive.

  7. The U.S. Educational Seismology Network (USESN)

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

    Two years ago, a new national science outreach initiative, the U.S. Educational Seismology Network (USESN), was initiated under the auspices of the IRIS Consortium. The mission of the USESN is to promote the use of seismo¬graphs and seismic data for science education. This project has emerged out of several independent educational seismology initiatives, whose collective efforts have resulted in the development of a 300+ station national school seismograph network. The USESN effort is envisioned to include support for a full range of educational seismograph options, from display-oriented, stand-alone systems to networked broadband instruments. USESN seeks to provide an organizational structure for the coordination of the numerous educational seismology activities that are developing across the country. In this presentation, we focus on the goals and opportunities for a collective educational seismology enterprise. The primary goals of the USESN initiative are disseminate high-quality curricular materials and educational services that promote the use of seismology in science education; and (3) provide an organizational framework for coordination and advocacy of educational seismology across the country. Based on discussions at a 2003 national workshop, we summarize the primary goals for the initiative in terms of priorities for curriculum development, professional development, technical issues, and organizational structure. Additional information about the USESN initiative can be found at http://www.indiana.edu/~usesn and http://www.iris.edu/.

  8. Seismological Constraints on Geodynamics

    NASA Astrophysics Data System (ADS)

    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

  9. Bulgarian National Digital Seismological Network

    NASA Astrophysics Data System (ADS)

    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

  10. UTIG's Contributions to Seismology in K-12 Classrooms

    NASA Astrophysics Data System (ADS)

    Ellins, K. K.

    2004-12-01

    The University of Texas Institute for Geophysics (UTIG) conducts research in many areas of seismology, including the study of earthquakes, the structure of Earth's interior and targeted geologic settings, and the development of methods to monitor nuclear explosions. In addition, UTIG scientists engage in educational outreach that takes seismology and its applications into K-12 classrooms. Activities include (1) the development of standards-aligned, inquiry-based curriculum materials that use real seismic data to convey concepts in earthquake seismology and which introduce modern technologies based on the principles of seismology; (2) a year-long teacher professional development institute that incorporates seismology and teacher workshops at which scientists, GK-12 Fellows and teachers team up to deliver science content and learning activities; and (3) a "Teacher in the Field" program through which teachers have participated in marine geophysical cruises to study tectonic processes in the Bransfield Strait, Hess Deep, Terror Rift in the Ross Sea, the southeastern Caribbean, and the Blanco Fracture Zone. UTIG has supported these efforts through grants from the NSF and state agencies, and by partnering with other programs and organizations. For example, teacher workshops were organized around public lectures by IRIS/SSA Distinguished Speakers Roger Bilham (Global Death and Construction: Earthquakes on an Urban Planet) and David Wald (Rapid Earthquake Information: Citizen Science and New Tools for Emergency Response) and presented as part of The University of Texas Environmental Science Institute Outreach Lecture Series.

  11. Data User's Note: Apollo seismological investigations

    NASA Technical Reports Server (NTRS)

    Vostreys, R. W.

    1980-01-01

    Seismological objectives and equipment used in the passive seismic, active seismic, lunar seismic profiling, and the lunar gravimeter experiments conducted during Apollo 11, 12, 14, 15, 16, and 17 missions are described. The various formats in which the data form these investigations can be obtained are listed an an index showing the NSSDC identification number is provided. Tables show manned lunar landing missions, lunar seismic network statistics, lunar impact coordinate statistics, detonation masses and times of EP's, the ALSEP (Apollo 14) operational history; compressed scale playout tape availability, LSPE coverage for one lunation, and experimenter interpreted events types.

  12. Nuclear test ban verification: Recent Canadian research in forensic seismology

    SciTech Connect

    Chun, K.Y.

    1991-07-01

    Seismology provides the primary means for monitoring nuclear explosions that take place underground. Improved seismographic hardware, Canadian research expertise, and the availability of a vast proving ground (the Canadian land mass which bears close resemblance with other regions of nuclear test ban verification interest), are all helping Canada become an increasingly notable contributor to the highly specialized branch of forensic seismology. The report describes: (1) verification and its rationale; (2) the basic tasks of seismic verification; (3) the physical basis for earthquake/explosion source discrimination and explosion yield determination; (4) the technical problems pertaining to seismic monitoring of underground nuclear tests; (5) the basic problem solving strategy deployed by the forensic seismology research team at the University of Toronoto; and (6) the scientific significance of the team's research.

  13. Rotational Seismology Workshop of February 2006

    USGS Publications Warehouse

    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

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

    SciTech Connect

    Paulsson, B.N.P.

    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.

  15. On seismological moments and magnitudes

    USGS Publications Warehouse

    Bolt, B. A.

    1991-01-01

    My approach to seismology over the years has always been from the point of view of applied mathematics, as exemplified broadly by the work of the late Sir Harold Jeffreys and Professor K. E. Bullen. Both stresses the development of mathematics in the context of physical systems and of modeling, with an eye always on the side of inference. Seismology provided for them and still provides today the almost perfect paradigm; the problem is the resolution of the detailed consitution of the Earth and its geologically short-term dynamics. The latter part, includes, of course, seismic-risk estimation. The last 20 years have seen the construction of a brilliant theoretical  formalism for linear inverse problems in seismology , although, oddly enough, the current popular Earth models do not take account it. It is interesting too that the narrow opinion, prevelent a decade ago, to the effect that the traditional seismic body-wave approaches to structural definition were superceded, has been largely abandoned under today's banner of tomography-as though the Oldham-Jeffreys-Gutenbery inversions were not tomography. 

  16. Toward noncontacting seismology

    NASA Astrophysics Data System (ADS)

    van Wijk, K.; Scales, J. A.; Mikesell, T. D.; Peacock, J. R.

    2005-01-01

    Buried land mines and chemical waste may provide the contrast in elastic properties within the soil needed to achieve detection via near-surface seismic methods. The hazardous nature of these targets strongly indicates the use of noncontacting sources and receivers. A home-made ultrasonic parametric array allows us to insonify the soil with an intense beam of sound; this acoustic energy is converted to elastic waves in the soil. Our noncontacting seismometer is a microwave Doppler vibrometer that can detect seismic waves, even through grass. We believe that developments along these lines will ultimately lead to the ability to probe large areas of the near-surface in a safe and reliable fashion, without physically touching the ground.

  17. Seismology on Mars

    NASA Technical Reports Server (NTRS)

    Anderson, D. L.; Miller, W. F.; Latham, G. V.; Nakamura, Y.; Toksoz, M. N.; Dainty, A. M.; Duennebier, F. K.; Lazarewicz, A. R.; Kovach, R. L.; Knight, T. C. D.

    1977-01-01

    High-quality data (uncontaminated by lander or wind noise) obtained with a three-axis short-period seismometer operating on Mars in the Utopia Planitia region are analyzed. No large events have been detected during the first five months of operation covered in the present paper. This indicates that Mars is less seismically active than the earth. Winds, and therefore a seismic background, began to intrude into the nighttime hours, starting with sol 119 (sol is a Martian day). The seismic background correlates well with wind velocity, and is proportional to the square of the wind velocity, as is appropriate for turbulent flow. A local seismic event of a magnitude of 3 and a distance of 110 km was detected on sol 80. It is interpreted as a natural seismic event.

  18. Elastic Wave Propagation and Generation in Seismology

    NASA Astrophysics Data System (ADS)

    Lees, Jonathan M.

    The majority of mature seismologists of my generation were introduced to theoretical seismology via classic textbooks written in the early 1980s. Since this generation has matured and taken the mantle of teaching seismology to a new generation, several new books have been put forward as replacements, or alternatives, to the original classical texts. The target readers of the new texts range from beginner through intermediate to more advanced, although all have been attempts to improve upon what is now considered standard convention in quantitative seismology. To this plethora of choices we now have a new addition by Jose Pujol, titledElastic Wave Propagation and Generation in Seismology.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. The seismology of eta Bootes

    NASA Technical Reports Server (NTRS)

    Demarque, Pierre; Guenther, D. B.

    1995-01-01

    Some p-mode frequencies and other observations were used to determine the mass, the age and the helium abundance of eta Bootes. It is shown how, by direct application, the p-mode frequencies and stellar seismological tools help in constraining the physical parameters of eta Boo. The existence of mode bumping is confirmed and it is discussed how it may be used to refine the estimate of the eta Boo's age. The effect of the OPAL equation of state on the p-mode frequencies is described.

  1. Seismology

    ERIC Educational Resources Information Center

    Uhrhammer, Robert

    1978-01-01

    This past year has been a period of rethinking and consolidation of ideas on earthquake prediction. The Earthquake Hazards Reduction Act became public law. Significant advances in seismographic instrumentation and recording techniques took place and plans proceed to upgrade the capacity of some monitoring stations, using digital recording…

  2. Hellenic Seismological Network of Crete (HSNC): a new permanent seismological network in the Southern Aegean

    NASA Astrophysics Data System (ADS)

    Vallianatos, F.

    2009-04-01

    The Aegean region which comprises the Hellenic arc and the adjacent areas of the Greek mainland, the Aegean Sea and western Turkey, is one of the most seismically active zones of the world and the most active in western Eurasia due to the convergence between the African and Eurasian lithospheric plates. The seismic activity especially in the southern Aegean area is very intense and extends up to a depth of about 180 km. The seismicity of South Aegean is extremely high and is characterised by the frequent occurrence of large shallow and intermediate depth earthquakes. Crete marks the forearc high of the modern Hellenic subduction zone in the eastern Mediterranean. In order to in order to provide modern instrumental coverage of seismicity in the South Aegean, as well as some more insight into the stress and deformation fields, tectonics, structure and dynamics of the Hellenic Arc from which will be possible to retrieve information about the rupture process, a seismological network of high dynamic range is installed. It is called HSNC (Hellenic Seismological Network of Crete) and consists of 11 permanent seismological stations equipped with short period and broadband seismographs coupled with 3rd generation 24bit data loggers as well as from 4 accelerographs. HSNC is rapidly expanded and expected to have complete 18 permanent seismological stations and 12 accelerographs by the end of April 2009. Data transmission and telemetry is based on conventional TCP/IP communication using a hybrid network consisting of dedicated wired ADSL links as well as VSAT links by using the private satellite hub located at lab of Geophysics & Seismology (LGS) at Chania, Crete. Data centre is equipped with a high performance computing cluster capable of providing real time estimations as well as to support great number experimental investigations using the on line or offline data streams. Prototype software solutions are developed for monitoring and controlling network elements, to automate

  3. Preseismic Velocity Changes Observed from Active Source Monitoringat the Parkfield SAFOD Drill Site

    SciTech Connect

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

    2008-06-10

    Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. Here we show that such stress changes are measurable by exploiting the stress dependence of seismic wave speed from an active source cross-well experiment conducted at the SAFOD drill site. Over a two-month period we observed an excellent anti-correlation between changes in the time required for an S wave to travel through the rock along a fixed pathway--a few microseconds--and variations in barometric pressure. We also observed two large excursions in the traveltime data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. Interestingly, the two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies.

  4. An Educator's Resource Guide to Earthquakes and Seismology

    NASA Astrophysics Data System (ADS)

    Johnson, J.; Lahr, J. C.; Butler, R.

    2007-12-01

    When a major seismic event occurs, millions of people around the world want to understand what happened. This presents a challenge to many classroom science teachers not well versed in Earth science. In response to this challenge, teachers may try surfing the Internet to ferret out the basics. Following popular links can be time consuming and frustrating, so that the best use is not made of this "teachable moment." For isolated rural teachers with limited Internet access, surfing for information may not be a viable option. A partnership between EarthScope/USArray, High Lava Plains Project (Carnegie Institution/Arizona State University, Portland State University, and isolated K-12 schools in rural SE Oregon generated requests for a basic "Teachers Guide to Earthquakes." To bridge the inequalities in information access and varied science background, EarthScope/USArray sponsored the development of a CD that would be a noncommercial repository of Earth and earthquake-related science resources. A subsequent partnership between the University of Portland, IRIS, the USGS, and Portland-area school teachers defined the needs and provided the focus to organize sample video lectures, PowerPoint presentations, new Earth-process animations, and activities on a such a large range of topics that soon the capacity of a DVD was required. Information was culled from oft-referenced sources, always seeking clear descriptions of processes, basic classroom-tested instructional activities, and effective Web sites. Our format uses a master interactive PDF "book" that covers the basics, from the interior of the Earth and plate tectonics to seismic waves, with links to reference folders containing activities, new animations, and video demos. This work-in-progress DVD was initially aimed at middle school Earth-science curriculum, but has application throughout K-16. Strong support has come from university professors wanting an organized collection of seismology resources. The DVD shows how

  5. Upgrading the Northern Finland Seismological Network

    NASA Astrophysics Data System (ADS)

    Narkilahti, Janne; Kozlovskaya, Elena; Silvennoinen, Hanna; Hurskainen, Riitta; Nevalainen, Jouni

    2016-04-01

    The Finnish National Seismic Network (FNSN) comprises national Helsinki University Seismological network (HE) ISUH and the Northern Finland Seismological Network (FN) hosted by the Sodankylä Geophysical Observatory (SGO) of the University of Oulu. The FN network currently consists of four real-time permanent stations equipped with Streckeisen STS-2 broad band seismometers that are recording continuous digital seismic data. At present, the network is a part of GEOFON Extended Virtual Network and of the ORFEUS Virtual European Broadband Seismograph Network. In the future, the network will be the part of EPOS-European Plate Observing System research infrastructure. As a part of EPOS project activities, the SGO started to upgrade their own network in 2014. The main target of the network upgrade is to increase the permanent station coverage in the European Arctic region, particularly behind the Polar Circle. Another target is to transform the network into a broadband seismic array capable to detect long-period seismic signals originating from seismic events in the Arctic. The first upgrade phase started in 2014, when two new stations were installed and now are working in the test regime. These stations are used as prototypes for testing seismic equipment and technical solutions for real-time data transmission and vault construction under cold climate conditions. The first prototype station is installed in a surface vault and equipped with Nanometrics Trillium 120P sensor, while the other one is installed in a borehole and equipped with Trillium Posthole seismometer. These prototype stations have provided to us valuable experience on the downhole and surface deployment of broadband seismic instruments. We also have been able to compare the capabilities and performance of high sensitivity broadband sensor deployed in borehole with that deployed in surface vault. The results of operation of prototype stations will be used in site selection and installation of four new

  6. Global teaching of global seismology

    NASA Astrophysics Data System (ADS)

    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.

  7. Testing the seismology-based landquake monitoring system

    NASA Astrophysics Data System (ADS)

    Chao, Wei-An

    2016-04-01

    I have developed a real-time landquake monitoring system (RLMs), which monitor large-scale landquake activities in the Taiwan using real-time seismic network of Broadband Array in Taiwan for Seismology (BATS). The RLM system applies a grid-based general source inversion (GSI) technique to obtain the preliminary source location and force mechanism. A 2-D virtual source-grid on the Taiwan Island is created with an interval of 0.2° in both latitude and longitude. The depth of each grid point is fixed on the free surface topography. A database is stored on the hard disk for the synthetics, which are obtained using Green's functions computed by the propagator matrix approach for 1-D average velocity model, at all stations from each virtual source-grid due to nine elementary source components: six elementary moment tensors and three orthogonal (north, east and vertical) single-forces. Offline RLM system was carried out for events detected in previous studies. An important aspect of the RLM system is the implementation of GSI approach for different source types (e.g., full moment tensor, double couple faulting, and explosion source) by the grid search through the 2-D virtual source to automatically identify landquake event based on the improvement in waveform fitness and evaluate the best-fit solution in the monitoring area. With this approach, not only the force mechanisms but also the event occurrence time and location can be obtained simultaneously about 6-8 min after an occurrence of an event. To improve the insufficient accuracy of GSI-determined lotion, I further conduct a landquake epicenter determination (LED) method that maximizes the coherency of the high-frequency (1-3 Hz) horizontal envelope functions to determine the final source location. With good knowledge about the source location, I perform landquake force history (LFH) inversion to investigate the source dynamics (e.g., trajectory) for the relatively large-sized landquake event. With providing

  8. Gamma source for active interrogation

    DOEpatents

    Leung, Ka-Ngo; Lou, Tak Pui; Barletta, William A.

    2009-09-29

    A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

  9. Gamma source for active interrogation

    SciTech Connect

    Leung, Ka-Ngo; Lou, Tak Pui; Barletta, William A.

    2012-10-02

    A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

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

    USGS Publications Warehouse

    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

  11. Educational Seismology in Michigan: The MIQuakes Network

    NASA Astrophysics Data System (ADS)

    Fujita, K.; DeWolf, C. L.; Ruddock, J.; Svoboda, M. R.; Sinclair, J.; Schepke, C.; Waite, G. P.

    2013-12-01

    MIQuakes is a K-14 educational seismograph network currently consisting of 17 schools, mostly located in Michigan's lower peninsula. It is operated under the auspices of the Michigan Earth Science Teachers Association (MESTA) and is part of the IRIS Seismographs in Schools program. Although individual teachers in Michigan have had instruments as early as 1992, MESTA formed MIQuakes in 2010 to support the development of activities associated with classroom seismology appropriate for grades 6-12 and relevant to the Midwest, using locally recorded data. In addition, the deployment of the EarthScope transportable array in Michigan during 2011-2014 offered a tie in with a national-level research program. Michigan State University (MSU) and Michigan Tech provide content and technical support. In keeping with MESTA's philosophy of 'teachers helping teachers,' MIQuakes became, first and foremost, a group supported by teachers. Earthquake 'alerts' initially issued by MSU, were soon taken over by teachers who took the initiative in alerting each other to events, especially those that occurred during the school day. In-service teachers and university faculty have jointly organized workshops at MSU and at MESTA conferences - with teachers increasingly providing activities for sharing and relating the program to the new national standards. Workshops held to date have covered such topics as recognizing arrivals, filtering, focal mechanisms, and the Tohoku earthquake. As the group has grown, the degree of involvement and level of expertise have become broader, resulting in very different expectations from different teachers. How to keep the network cohesive, yet meet the needs of the individual members, will be one of the challenges of the next few years. Three levels of involvement by teachers are seen in the near term: those who operate their own classroom seismometer (currently either the short-period IRIS AS-1 or the broadband EAS-S102 seismometers); those who stream a nearby

  12. Measuring the magnetic field of a trans-equatorial loop system using coronal seismology

    NASA Astrophysics Data System (ADS)

    Long, David; Perez-Suarez, David; Valori, Gherardo

    2016-05-01

    First observed by SOHO/EIT, "EIT waves" are strongly associated with the initial evolution of coronal mass ejections (CMEs) and after almost 20 years of investigation a consensus is being reached which interprets them as freely-propagating waves produced by the rapid expansion of a CME in the low corona. An "EIT wave" was observed on 6 July 2012 to erupt from active region AR11514 into a particularly structured corona that included multiple adjacent active regions as well as an adjacent trans-equatorial loop system anchored at the boundary of a nearby coronal hole. The eruption was well observed by SDO/AIA and CoMP, allowing the effects of the "EIT wave" on the trans-equatorial loop system to be studied in detail. In particular, it was possible to characterise the oscillation of the loop system using Doppler velocity measurements from CoMP. These Doppler measurements were used to estimate the magnetic field strength of the trans-equatorial loop system via coronal seismology. It was then possible to compare these inferred magnetic field values with extrapolated magnetic field values derived using a Potential Field Source Surface extrapolation as well as the direct measurements of magnetic field provided by CoMP. These results show that the magnetic field strength of loop systems in the solar corona may be estimated using loop seismology.

  13. Modeling Approaches in Planetary Seismology

    NASA Technical Reports Server (NTRS)

    Weber, Renee; Knapmeyer, Martin; Panning, Mark; Schmerr, Nick

    2014-01-01

    Of the many geophysical means that can be used to probe a planet's interior, seismology remains the most direct. Given that the seismic data gathered on the Moon over 40 years ago revolutionized our understanding of the Moon and are still being used today to produce new insight into the state of the lunar interior, it is no wonder that many future missions, both real and conceptual, plan to take seismometers to other planets. To best facilitate the return of high-quality data from these instruments, as well as to further our understanding of the dynamic processes that modify a planet's interior, various modeling approaches are used to quantify parameters such as the amount and distribution of seismicity, tidal deformation, and seismic structure on and of the terrestrial planets. In addition, recent advances in wavefield modeling have permitted a renewed look at seismic energy transmission and the effects of attenuation and scattering, as well as the presence and effect of a core, on recorded seismograms. In this chapter, we will review these approaches.

  14. The Euro-Med Seismological portal and its webservices for interactive and automatic data access

    NASA Astrophysics Data System (ADS)

    Frobert, Laurent; Bossu, Rémy; Kaestli, Philipp; Küng, Josef; Spinuso, Alessandro; Trani, Luca; Van Eck, Torild; Wenzel, Helmut

    2014-05-01

    The seismic portal (www.seismicportal.eu) aims at Improving discoverability, access and usability of data and products for seismology and seismic hazard and risk studies. Its development was initiated during the FP6-NERIES (Network of Research Infrastructure for European Seismology) project to deal with seismological data and is being extended within the FP7-NERA (Network of European Research Infrastructures for Earthquake Risk Assessment and Mitigation) project to include seismic hazard results of the FP7-SHARE project and a risk component derived from the FP7-SYNER-G (Systemic Seismic Vulnerability and Risk Analysis for Buildings, Lifeline Networks and Infrastructures Safety Gain) project. Its long-term sustainability is based on coordination and integration with project on computational seismology such as VERCE (Virtual Earthquake Research Community for Europe), transformative initiatives of EPOS (European Plate Observing System) and GEM (Global Earthquake Model) as well as key actor such as the USGS (US Geological Survey), the ISC (International Seismological Centre) or IRIS (Incorporated Research Institutions for Seismology). Open source technologies and standards such as OGC ensure interoperability within other Earth sciences development. Data is accessed by three different means: the portal for interactive access and data discovery, invocation of webservices for automatic access and soon standing order for data. The presentation will be based on a poster and live demo.

  15. Advanced Light Source Activity Report 2000

    SciTech Connect

    Greiner, A.; Moxon, L.; Robinson, A.; Tamura, L.

    2001-04-01

    This is an annual report, detailing activities at the Advanced Light Source for the year 2000. It includes highlights of scientific research by users of the facility as well as information about the development of the facility itself.

  16. ObsPy: A Python Toolbox for Seismology and Seismological Observatories

    NASA Astrophysics Data System (ADS)

    Krischer, Lion; Megies, Tobias; Barsch, Robert; Beyreuther, Moritz; Wassermann, Joachim

    2013-04-01

    Python combines the power of a full-blown programming language with the flexibility and accessibility 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. ObsPy extends Python's capabilities to fit the specific needs that arise when working with seismological data. It a) comes with a continuously growing signal processing toolbox that covers most tasks common in seismological analysis, b) provides read and write support for many common waveform, station and event metadata formats and c) enables access to various data centers, webservices and databases to retrieve waveform data and station/event metadata. In combination with mature and free Python packages like NumPy, SciPy, Matplotlib, IPython and PyQt, ObsPy makes it possible to develop complete workflows in Python, ranging from reading locally stored data or requesting data from one or more different data centers via signal analysis and data processing to visualization in GUI and web applications, output of modified/derived data and the creation of publication-quality figures. All functionality is extensively documented and the ObsPy Tutorial and Gallery give a good impression of the wide range of possible use cases. ObsPy is tested and running on Linux, OS X and Windows and comes with installation routines for these systems. ObsPy is developed in a test-driven approach and is available under the GPL/LGPLv3 open source licences. Users are welcome to request help, report bugs, propose enhancements or contribute code via either the user mailing list or the project page on GitHub.

  17. The GANSSER seismological network in Bhutan

    NASA Astrophysics Data System (ADS)

    Hetényi, G.

    2013-12-01

    Our project investigates the Geodynamics ANd Seismic Structure of the Eastern-Himalaya Region (GANSSER). It aims to reveal the first seismological images beneath Bhutan and as such is a tribute to the late Augusto Gansser, geological discoverer of Bhutan [1]. Project GANSSER builds on the deployment of a temporary broadband seismometer network. This consists of 38 stations deployed across the Kingdom of Bhutan. Two south-north segments in the western and eastern part of the country constitute densely spaced lines of ca. 7 km inter-station distance with respectively 16 and 14 stations. The main technique to apply is receiver functions in order to image the Moho as it deepens from India to Tibet, thus revealing how the crust thickens in the Eastern Himalayas. Further 8 stations are located in-between these lines, in the central part of the country. The main purpose here is to characterize the seismicity of the country in a homogeneous manner. Altogether, the station network will allow the application of different classical seismological techniques, such as teleseismic, local earthquake, ambient noise and attenuation tomography. The dataset will also be exploited to try to locate landslides that cause a significant hazard, especially in and after the summer monsoon season. The station network described above has been deployed in January 2013 and is planned to operate until spring 2014. A first visit to the stations in April 2013 found operational conditions better than the average for temporary seismological networks. Data recovery in this time period exceeded 90%. Power spectral density diagrams indicate that the noise levels at our station sites are within the bounds of the Peterson Noise Model bounds [2] and in some cases are significantly less than the high-noise model. Starting April 2013 remote communications pathways with one third of the stations are tested. The scientific goals of Project GANSSER include: the determination of the structure and physical

  18. Real-Time Seismology in Portugal

    NASA Astrophysics Data System (ADS)

    Custodio, S.; Marreiros, C.; Carvalho, S.; Vales, D.; Lima, V.; Carrilho, F.

    2012-12-01

    Portugal is located next to the plate boundary between Eurasia (Iberia) and Africa (Nubia). The country has been repeatedly affected by some of the largest earthquakes, both onshore and offshore, in the historical European record, including the largest historical European earthquake, the great Lisbon earthquake of 1755 (~M8.5). The Portuguese territory has suffered directly the consequences of strong ground shaking (collapse of buildings, etc) and also some of the most destructive consequences of earthquakes (e.g. tsunamis, fires, etc). However, the rate of tectonic deformation in the Portuguese territory is low (the Eurasian-African plates converge at a rate of ~ 5 mm/yr), which results in long recurrence intervals between earthquakes. This low to moderate rate of seismic activity has two major negative effects: 1) it is difficult to study the regional seismo-tectonics with traditional passive methods; 2) the population is little aware of earthquake risk and unprepared to react in case of disaster. In this scenario, real-time seismology is key to monitoring earthquake crisis in real-time, providing early warnings about potentially destructive events, and assisting in the channeling of recovery efforts in case of disaster. In this paper we will present the real-time algorithms implemented at Instituto de Meteorologia (IM), the institution responsible for seismic monitoring in Portugal. In particular, we will focus on the following aspects: 1) Data collection and real-time transmission to the headquarters. Broadband seismological stations are owned and operated by five different institutions. The last years have witnessed an effort for integration, and presently most data arrives at IM lab in real-time. 2) Earthquake location and local magnitude determination. Data is automatically analyzed in order to obtain a first earthquake hypocenter and ML. While this process is mostly automatic, it still requires the revision by an operator, who is available 24h. 3

  19. Research on history of Chinese seismology

    NASA Astrophysics Data System (ADS)

    Feng, Rui; Wu, Yuxia

    2010-06-01

    The history of Chinese seismology can be traced back to four thousand years before and divided into four stages, i.e., primitive knowledge, worship of nature, perceptual knowledge and scientific research. The second stage ran in the whole Qin-Han dynasties, and the fourth stage began from Emperor Kangxi in Qing Dynasty and continued to the present. So far China has made four great contributions to seismological development of the world, i.e., the invention of Heng Zhang’s seismoscope, great amount of historical records of earthquakes of four thousand years, most abundant anomaly data before earthquakes, and successful practice of earthquake prediction in Haicheng. However, the seismological research in China at present is still on the junior and developing stage. Now we have been carrying on some recessively historical load in our mind such as the subconsciousness of absolute obedience, habit of phenomenological study as well as the methods of philosophical analysis without sincerity. For constructing a high-level Chinese culture in seismological research, we need to pay attention to combining the phenomenological research with experiment, observation and theory study. It is also suggested to take the appropriated measures matched with the present research level in seismology, as well as to promote coexisting and merging of multi-cultures.

  20. Statistical Seismology and Induced Seismicity

    NASA Astrophysics Data System (ADS)

    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

  1. Northern Finland Seismological Network: a tool to analyse long-period seismological signals

    NASA Astrophysics Data System (ADS)

    Kozlovskaya, Elena; Hurskainen, Riitta

    2014-05-01

    Sodankylä Geophysical Observatory of Oulu University (SGO) is located at 67° 22' N, 26° 38' E in the middle of Finnish Lapland. It was established in 1913 and since then has gained a long experience in carrying out multidisciplinary geophysical observations in Arctic environment. Seismological observations at the University of Oulu and SGO have been carried out since 1965. During 2005-2008 the SGO modernized own sort-period permanent seismic network, enhanced the number of stations and equipped them with the VBB seismic sensors. The stations are located at latitudes from 650 N to 680 N. They form the Northern Finland Seismological Network (NFSN) that will be the part of Finnish EPOS research infrastructure in the future. The continuous seismic data of the NFSN are archived in the GFZ Seismological Data Archive of the GeoForschungsZentrum Potsdam (Germany) and in the own backup archive of the SGO. At the moment, the data of the NFSN are routinely used for monitoring of seismic activity in Northern Europe and world-wide and information about seismic events is published in several on-line bulletins. Due to the recent mineral exploration and mining boom in northern Finland, a new task for the NFSN will be recording and analysis of mining-induced seismicity and estimating of seismic hazard associated with it. During installation of instruments of the NFSN, particular measures were taken in order to improve instruments performance at long periods. In Arctic conditions the performance of broadband seismic instruments is affected by large ambient temperature variations and geomagnetic field disturbances (geomagnetic pulsations). In 2007-2009 the NFSN was a part of the POLENET/LAPNET IPY project. In addition to lithosphere structure studies, the project aimed at registration of long-period glacial seismic events originating from Greenland Ice Sheet. Analysis of data recorded by the NFSN during the IPY demonstrated that the network is capable to record not only long

  2. Coronal seismology using transverse loop oscillations

    NASA Astrophysics Data System (ADS)

    Verwichte, E.; Foullon, C.; Van Doorsselaere, T.; Smith, H. M.; Nakariakov, V. M.

    2009-12-01

    Coronal seismology exploits the properties of magnetohydrodynamics in the corona of the Sun to diagnose the local plasma. Therefore, seismology complements direct diagnostic techniques, which suffer from line-of-sight integration or may not give access to all physical quantities. In particular, the seismological exploitation of fast magnetoacoustic oscillations in coronal loops provides information about the global magnetic and density structuring of those loops acting as wave guides. From the oscillation period and damping time it is shown how to obtain information about the local coronal magnetic field as well as the longitudinal and transverse structuring. Furthermore, such studies motivate the development of coronal wave theories, which are also relevant to the coronal heating problem.

  3. Nonlinear seismology a reality. The quantitative data

    NASA Astrophysics Data System (ADS)

    Marmureanu, G.; Cioflan, C. O.; Marmureanu, A.

    2012-04-01

    Nonlinear effects in ground motion during large earthquakes have long been a controversial issue between seismologists and geotechnical engineers. The central point of the discussion in last 10-15 years was whether soil amplification is function of earthquake magnitude. Laboratory tests made by using Hardin or Drnevich resonant columns consistently show the decreasing of dynamic torsion function(G) and increasing of torsion damping function(D%) with shear strains(γ) induced by deep strong Vrancea earthquakes; G = G(γ), respectively, D%= D%(γ),therefore nonlinear viscoelastic constitutive laws are required. Nonlinear amplification at sediments sites appears to be more pervasive than seismologists used to think...Any attempt at seismic zonation must take into account the local site condition and this nonlinear amplification (Aki, A., Local Site Effects on Weak and Strong Ground Motion, Tecto-nophysics, 218, pp.93-111, 1993). The difficulty to seismologists in demonstrating the nonlinear site effects has been due to the effect being overshadowed by the overall patterns of shock generation and propagation. In other words, the seismological detection of the nonlinear site effects requires a simultaneous understanding of the effects of earthquake source, propagation path and local geological site conditions. In main ground motion equation, ground displacement u(t) has general form: u(t)=s(t)*g(t)*i(t),where s(t),g(t) and i(t) are source, propagation and, respectively, instrument recording functions. The authors, in order to make quantitative evidence of large nonlinear effects, introduced and developed the concept of the nonlinear spectral amplification factor (SAF) as ratio between maximum spectral absolute acceleration (Sa), relative velocity (Sv ), relative displacement (Sd) from response spectra for a fraction of critical damping (ζ %) at fundamental period or any other period and peak values of acceleration (amax), velocity (vmax) and displacement (dmax

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    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. The activities that have been created and their corresponding Grand Challenge are: -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 introduces 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?). -A suite of activities that introduce students to oil and gas exploration, including an activity that

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

    NASA Astrophysics Data System (ADS)

    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

  7. Nars: Over 30 Years of Seismology

    NASA Astrophysics Data System (ADS)

    Paulssen, H.

    2014-12-01

    It is fair to say that modern seismology steadily evolved from a handful key initiatives and innovations dating back to the early 1980s. (1) The transition from non-mobile, narrow band sensors with analogue recording (pre-1980s) to portable, broadband sensors with digital recorders paved the way to flexible deployments, enabling various array and regional studies with the same instrumentation. Here I mention just two initiatives: NARS, which was the first digital, mobile network of broadband stations deployed in western Europe (1983-1987), and USarray (2003- ), which is the biggest program of recent times. Presently, innovative data acquisition systems for the oceans are underway and they will allow future imaging of the "inaccessible" parts of the Earth. (2) In the 1980s seismological data centers were set up to facilitate data archiving and distribution. Since then, open data exchange (not a matter of course) and easy data retrieval have become standard. The impact of this has been phenomenal: most observational studies efficiently retrieve data from these main seismological data centers and the archived seismograms are used for various types of studies, carried out by different persons and groups. (3) Seismic tomography changed the face of seismological research. From travel time to waveform tomography, from ray theory to finite frequency tomography: new and improved tomographic techniques greatly enhanced our images (and understanding) of the Earth's interior. (4) Many of these developments would not have been possible without young, motivated, seismologists that were educated and stimulated by insightful supervisors. One person has had a major impact on all these fields. NARS in the title stands for Nolet greatly Advanced Research in Seismology.

  8. SEIS-PROV: Practical Provenance for Seismological Data

    NASA Astrophysics Data System (ADS)

    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.

  9. Tsunami Ionospheric warning and Ionospheric seismology

    NASA Astrophysics Data System (ADS)

    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

  10. Collecting and Using Low Latency Data at Berkeley Seismological Laboratory

    NASA Astrophysics Data System (ADS)

    Houlié, N.; Allen, R.; Hellweg, P.; Dreger, D.; Neuhauser, D.; Romanowicz, B.

    2008-12-01

    Northern California and the San Francisco Bay Area are among the US regions that combine high earthquake hazard and high population density. To rapidly and reliably monitor tectonic movement and develop an understanding of fault dynamics, measurements must cover a range of scales in time (0.1 s to years), space (mms to 100s of km) and displacement (microns to 10s of m). With these goals in mind, Berkeley Seismological Laboratory (BSL) continuously collects a wide variety of data at low latencies from seismic through geodetic, strain and electromagnetic instrumentation with sampling rates spanning 0.001 sps to 500 sps. Data from broadband seismometers and accelerometers, generally with latencies of less than 10 s, contribute to real time earthquake monitoring in Northern California including rapid assessments of source (moment tensor and finite fault) and shaking (ShakeMap). The BSL is also currently operating a real time system in test mode, using these data for earthquake early warning (ElarmS). Data from these instruments are also used for research on earthquake sources and scaling, fault-related tremor and studies of local, regional and global velocity structure. Low latency GPS data can complement seismic data, contributing robust real time continuous information especially for large earthquakes, and can potentially contribute to early warning. GPS-derived static deformation gives an independent estimate of fault orientation and dimensions, scalar seismic moment and magnitude. It also can extend the upper limits of a strong motion network to include the displacements of tens of meters expected in large and great earthquakes, and in the near field is less likely to be clipped during large movements. In an active tectonic context such as Northern California, low latency is important for data transmission, but also for reliability. At the BSL we are committed to using telemetry that is as robust as possible and often have more than one telemetry path to ensure

  11. Career in Feet-on Seismology

    NASA Astrophysics Data System (ADS)

    Van der Lee, S.

    2011-12-01

    My career award was for imaging the upper mantle beneath North America. The research proposed was timely because of Earthscope and novel because of the proposed simultaneous inversion of different types of seismic data as well as the inclusion of mineral physics data on the effects of volatiles on seismic properties of the mantle. This research has been challenging and fun and is still on-going. The educational component of my career award consists of feet-on and eyes-open learning of seismology through an educational kiosk and field trips to actual seismic stations. The kiosk and field station have both been growing over the years, as has the audience. I started with the field station in-doors, so it doubled as the kiosk along with a palmtop terminal. Groups of minority elementary school children would look at the mysterious hardware of the "field" station and then jump up and down so they could awe at the peaks in the graph on the palmtop screen that they created. This has evolved into a three-screen kiosk, of which one screen is a touch screen along with a demonstration seismometer. The field station is now in a goat shed near the epicenter of an actual 2010 earthquake inIllinois, which is soon to be replaced by a TA station of Earthscope. The audience has grown to entire grades of middle-school children and activities have evolved from jumping to team-experimentation and the derivation of amplitude-distance relationships following a collaborative curriculum. Addressing the questions in the session description: 1) Education is more fun and effective when one can work in a team with an enthusiastic educator. 2) My education activities are strongly related to my field of expertise but very loosely related to the research carried out with the career award. It appears that not the research outcomes are of interest to students, but instead the simplification and accessibility of the process of research that is of interest. 3) The education component of the career

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

    NASA Astrophysics Data System (ADS)

    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.

  13. The Albuquerque Seismological Laboratory Data Quality Analyzer

    NASA Astrophysics Data System (ADS)

    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

  14. Network of Research Infrastructures for European Seismology (NERIES)

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    NERIES (Network of Research Infrastructures for European Seismology) is an Integrated Infrastructure Initiative (I3) project within the Sixth Framework Programme of the European Commission (EC). The project consortium consists of 25 participants from 13 different European countries. It is currently the largest earth science project ever funded by the EC. The goal of NERIES is to integrate European seismological observatories and research institutes into one integrated cyber-infrastructure for seismological data serving the research community, civil protection authorities and the general public. The EC provides funds for the networking and research. The participants provide the necessary hardware investments, mostly through national resources. NERIES consists of 13 subprojects (networking and research activities) and 5 facilities providing access through grants (Transnational Access). The project is coordinated by ORFEUS in close cooperation with the EMSC. The individual subprojects address different issues such as: extension of the Virtual European Broadband Seismic Network (VEBSN) from 140 to about 500 stations, implementing the core European Integrated Waveform Data Archive (EIDA) consisting of ODC-KNMI, GFZ, INGV and IPGP and a distributed archive of historical Data. Providing access to data gathered by acceleration networks within Europe and its surroundings and deploys Ocean Bottom Seismometers in coordination with relevant Ocean bottom projects like ESONET. Tot facilitate access to this diverse and distributed data NERIES invests a significant portion of its resources to implementing a portal for which a beta release is planned to be release in the autumn of 2008. The research project main goal is to produce products and tools facilitating data interpretation and analysis. These tools include a European reference (velocity) model, real-time hazard tools, shakemaps and lossmaps, site response determination software and tools, and automatic tools to manage and

  15. CSDP: Seismology of continental thermal regime

    SciTech Connect

    Aki, K.

    1989-04-01

    This is a progress report for the past one year of research (year 2 of 5-year project) under the project titled CSDP: Seismology of Continental Thermal Regime'', in which we proposed to develop seismological interpretation theory and methods applicable to complex structures encountered in continental geothermal areas and apply them to several candidate sites for the Continental Scientific Drilling Project. During the past year, two Ph.D. thesis works were completed under the present project. One is a USC thesis on seismic wave propagation in anisotropic media with application to defining fractures in the earth. The other is a MIT thesis on seismic Q and velocity structure for the magma-hydrothermal system of the Valles Caldera, New Mexico. The P.I. co-organized the first International Workshop on Volcanic Seismology at Capri, Italy in October 1988, and presented the keynote paper on the state-of-art of volcanic seismology''. We presented another paper at the workshop on Assorted Seismic Signals from Kilauea Volcano, Hawaii. Another international meeting, namely, the Chapman Conference on seismic anisotropy in the earth's crust at Berkeley, California in May 1988, was co-organized by the co-P.I. (P.C.L), and we presented our work on seismic waves in heterogeneous and anisotropic media. Adding the publications and presentations made in the past year to the list for the preceding year, the following table lists 21 papers published, submitted or presented in the past two years of the present project. 65 refs., 334 figs., 1 tab.

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

    PubMed

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

    2008-07-10

    Measuring stress changes within seismically active fault zones has been a long-sought goal of seismology. One approach is to exploit the stress dependence of seismic wave velocity, and we have investigated this in an active source cross-well experiment at the San Andreas Fault Observatory at Depth (SAFOD) drill site. Here we show that stress changes are indeed measurable using this technique. Over a two-month period, we observed an excellent anti-correlation between changes in the time required for a shear wave to travel through the rock along a fixed pathway (a few microseconds) and variations in barometric pressure. We also observed two large excursions in the travel-time data that are coincident with two earthquakes that are among those predicted to produce the largest coseismic stress changes at SAFOD. The two excursions started approximately 10 and 2 hours before the events, respectively, suggesting that they may be related to pre-rupture stress induced changes in crack properties, as observed in early laboratory studies. PMID:18615082

  17. 3-D seismology in the Arabian Gulf

    SciTech Connect

    Al-Husseini, M.; Chimblo, R.

    1995-08-01

    Since 1977 when Aramco and GSI (Geophysical Services International) pioneered the first 3-D seismic survey in the Arabian Gulf, under the guidance of Aramco`s Chief Geophysicist John Hoke, 3-D seismology has been effectively used to map many complex subsurface geological phenomena. By the mid-1990s extensive 3-D surveys were acquired in Abu Dhabi, Oman, Qatar and Saudi Arabia. Also in the mid-1990`s Bahrain, Kuwait and Dubai were preparing to record surveys over their fields. On the structural side 3-D has refined seismic maps, focused faults and fractures systems, as well as outlined the distribution of facies, porosity and fluid saturation. In field development, 3D has not only reduced drilling costs significantly, but has also improved the understanding of fluid behavior in the reservoir. In Oman, Petroleum Development Oman (PDO) has now acquired the first Gulf 4-D seismic survey (time-lapse 3D survey) over the Yibal Field. The 4-D survey will allow PDO to directly monitor water encroachment in the highly-faulted Cretaceous Shu`aiba reservoir. In exploration, 3-D seismology has resolved complex prospects with structural and stratigraphic complications and reduced the risk in the selection of drilling locations. The many case studies from Saudi Arabia, Oman, Qatar and the United Arab Emirates, which are reviewed in this paper, attest to the effectiveness of 3D seismology in exploration and producing, in clastics and carbonates reservoirs, and in the Mesozoic and Paleozoic.

  18. Innovative Resources for Seismology at School with the French Educational Seismological Network

    NASA Astrophysics Data System (ADS)

    Berenguer, J. L.; Courboulex, F.; Balestra, J.; Nolet, G.; Lognonne, P. H.

    2014-12-01

    The original and innovative aspect of this programme stems from giving students the opportunity to install a seismometer in their school. The recorded signals, reflecting regional or global seismic activity, feed into an on-line database, a genuine seismic resource centre and a springboard for educational and scientific activities. The network 'EduSismo' (numbering some hundred stations installed in metropolitan France, the overseas departments and territories and a few French high schools abroad) is the outgrowth of an experiment conducted some twenty years back. Since then, the programme implemented has gone beyond simply acquiring seismic signals, which could have been procured by research and monitoring centres. By appropriating a scientific measurement, the student becomes personally involved and masters complex concepts about geophysics and geosciences. The development of simple devices and the design of concrete experiments associated with an investigative approach make it possible to instil the students with a high-quality scientific culture and an education about risks. Today, this programme is expanding with new tools providing by new research projects. Since last year, students can investigate ocean sound recorded by 'Mermaid' buoys and downloaded directly the data in the schools. Geosciences at school are opening new activities with seismic data from the ocean but also study of oceanographic currents or atmospheric events. We are also preparing actively the French E&O plan for SEIS-InSight (the future mission on Mars). InSight (Interior exploration using Seismic Investigation, Geodesy and Heat Transport) is a NASA Discovery Program mission that would place a single geophysical lander on Mars to study its deep interior. This program will provide to the schools a lot of innovative tools related to scientific culture to bring more geosciences into the classroom. As in the past, the French educational network will get the benefit of these new research

  19. Crosswell CASSM(Continuous Active-Source Seismic Monitoring): Recent Developments (Invited)

    NASA Astrophysics Data System (ADS)

    Daley, T. M.; Niu, F.; Ajo Franklin, J. B.; Solbau, R.; Silver, P. G.

    2009-12-01

    Continuous active-source monitoring using borehole sources and sensors in a crosswell configuration has proven to be a useful tool for monitoring subsurface processes (Silver, et al, 2007; Daley, et al, 2007; Niu, et al, 2008). This recent work has focused on two applications: monitoring stress changes related to seismicity and monitoring changes in fluid distribution related to geologic storage of CO2. Field tests have demonstrated precision in travel time measurement of up to 1.1 x 10-7 s, and in velocity perturbation measurement of up to 1.1 x 10-5 (Niu, et al 2008). In this talk I will summarize our preceding work and discuss current developments. Current efforts address both hardware and design challenges to improving the methodology. Hardware issues include deployment of multiple piezoelectric sources in shallow and deep boreholes, source and sensor deployment on tubing inside casing, and deployment with other monitoring instrumentation. Design issues are focused on use of multiple sources and/or sensors to obtain optimal spatial resolution for monitoring processes in the interwell region. This design issue can be investigated with optimal experiment design theory. New field experiments for monitoring seismicity (at SAFOD) and CO2 injection (at a US Dept of Energy pilot) are in the design/deployment stage. Current status of these projects will be discussed. References: Silver, P.G., Daley, T.M., Niu, F., Majer, E.L., 2007, Active source monitoring of crosswell seismic travel time for stress induced changes, Bulletin of Seismological Society of America, v97, n1B, p281-293. Daley, T.M., R.D. Solbau, J.B. Ajo-Franklin, S.M. Benson, 2007, Continuous active-source monitoring of CO2 injection in a brine aquifer, Geophysics, v72, n5, pA57-A61, DOI:10.1190/1.2754716. Niu, F., Silver, P.G., Daley, T.M., Cheng, X., Majer, E.L., 2008, Preseismic velocity changes observed from active source monitoring at the Parkfield SAFOD drill site, Nature, 454, 204-208, DOI:10

  20. [Description of the seismological network of the Venezuelan Andes].

    PubMed

    Guada, Carlos; Morandi, María; Silva, José

    2003-01-01

    Western Venezuela shows a broad zone characterized by a moderate seismicity level, which has been the scenery of various historic earthquakes of destructive character. The beginning of the seismic instrumentation in the area dates from 1969, nevertheless it was 10 years later when the seismological network of the Venezuelan Andes (REDSAV) was permanently installed in order to characterize the regional earthquake activity. The REDSAV is an array of 10 remote seismic stations that sends the seismic signals by analog telemetry to the central station, located in the city of Mérida, where the digitalization, automatic event detection in real time and the analysis and off-line processing of the seismic information is carried out. During the last 10 years important advances have been taken place in terms of its operativity, which includes a dynamic web site (http://lgula.ciens.ula.ve) with a catalog of western Venezuela earthquakes, where the user can visualize the seismograms, the P and S wave arrival time, the polarities and epicentral maps; moreover, it is possible to select events applying temporal, spatial and magnitute criteria. In this paper the technical characteristic of the equipment are described and the advances registered in the last years referring to the automatic acquisition system, processing of the information and seismologic catalog of the REDSAV, whose systematic use during a decade has permitted to gather the biggest information base of related with the seismicity of the south-western Venezuela. PMID:15916173

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

    SciTech Connect

    Swart, Peter K.; Dixon, Tim

    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.

  2. ObsPy: A Python Toolbox for Seismology

    NASA Astrophysics Data System (ADS)

    Wassermann, J. M.; Krischer, L.; Megies, T.; Barsch, R.; Beyreuther, M.

    2013-12-01

    Python combines the power of a full-blown programming language with the flexibility and accessibility 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. ObsPy is a community-driven, open-source project extending Python's capabilities to fit the specific needs that arise when working with seismological data. It a) comes with a continuously growing signal processing toolbox that covers most tasks common in seismological analysis, b) provides read and write support for many common waveform, station and event metadata formats and c) enables access to various data centers, webservices and databases to retrieve waveform data and station/event metadata. In combination with mature and free Python packages like NumPy, SciPy, Matplotlib, IPython, Pandas, lxml, and PyQt, ObsPy makes it possible to develop complete workflows in Python, ranging from reading locally stored data or requesting data from one or more different data centers via signal analysis and data processing to visualization in GUI and web applications, output of modified/derived data and the creation of publication-quality figures. All functionality is extensively documented and the ObsPy Tutorial and Gallery give a good impression of the wide range of possible use cases. ObsPy is tested and running on Linux, OS X and Windows and comes with installation routines for these systems. ObsPy is developed in a test-driven approach and is available under the LGPLv3 open source licence. Users are welcome to request help, report bugs, propose enhancements or contribute code via either the user mailing list or the project page on GitHub.

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

    NASA Astrophysics Data System (ADS)

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

    2009-12-01

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

  4. The behavior of transverse waves in nonuniform solar flux tubes. II. Implications for coronal loop seismology

    SciTech Connect

    Soler, Roberto; Terradas, Jaume; Oliver, Ramón; Goossens, Marcel

    2014-02-01

    The seismology of coronal loops using observations of damped transverse oscillations in combination with results from theoretical models is a tool to indirectly infer physical parameters in the solar atmospheric plasma. Existing seismology schemes based on approximations of the period and damping time of kink oscillations are often used beyond their theoretical range of applicability. These approximations assume that the variation of density across the loop is confined to a nonuniform layer much thinner than the radius of the loop, but the results of the inversion problem often do not satisfy this preliminary hypothesis. Here, we determine the accuracy of the analytic approximations of the period and damping time, and the impact on seismology estimates when largely nonuniform loops are considered. We find that the accuracy of the approximations when used beyond their range of applicability is strongly affected by the form of the density profile across the loop, that is observationally unknown and so must be arbitrarily imposed as part of the theoretical model. The error associated with the analytic approximations can be larger than 50% even for relatively thin nonuniform layers. This error directly affects the accuracy of approximate seismology estimates compared to actual numerical inversions. In addition, assuming different density profiles can produce noncoincident intervals of the seismic variables in inversions of the same event. The ignorance about the true shape of density variation across the loop is an important source of error that may dispute the reliability of parameters seismically inferred assuming an ad hoc density profile.

  5. Vertically Integrated Seismological Analysis II : Inference

    NASA Astrophysics Data System (ADS)

    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.

  6. Radio seismology of the outer solar corona

    NASA Astrophysics Data System (ADS)

    Zaqarashvili, Teimuraz; Melnik, Valentin; Brazhenko, Anatoliy; Panchenko, Mykhaylo; Konovalenko, Alexander; Dorovskyy, Vladimir; Rucker, Helmut

    2014-05-01

    Observed oscillations of coronal loops in extreme ultraviolet (EUV) lines have been successfully used to estimate plasma parameters in the inner corona (< 0.2R0, where R0 is the solar radius). However, coronal seismology in EUV lines fails for higher altitudes because of rapid decrease in line intensity. We aim to use radio observations to estimate the plasma parameters of the outer solar corona (> 0.2R0). We used the large Ukrainian radio telescope URAN-2 to observe type IV radio bursts at the frequency range of 8-32 MHz during the time interval of 09:50-12:30 UT on April 14, 2011. The burst was connected to C2.3 flare, which occurred in AR 11190 during 09:38-09:49 UT. The dynamic spectrum of radio emission shows clear quasi-periodic variations in the emission intensity at almost all frequencies. Wavelet analysis at four different frequencies (29 MHz, 25 MHz, 22 MHz, and 14 MHz) shows the quasi-periodic variation of emission intensity with periods of ~ 34 min and ~ 23 min. The periodic variations can be explained by the first and second harmonics of vertical kink oscillation of transequatorial coronal loops, which were excited by the same flare. The apex of transequatorial loops may reach up to 1.2 R0 altitude. We derive and solve the dispersion relation of trapped magnetohydrodynamic (MHD) oscillations in a longitudinally inhomogeneous magnetic slab. The analysis shows that a thin (with width to length ratio of 0.1), dense (with the ratio of internal and external densities of ≥ 20) magnetic slab with weak longitudinal inhomogeneity may trap the observed oscillations. Seismologically estimated Alfvén speed inside the loop at the height of ~ 1 R0 is ~ 1000 km s-1. The magnetic field strength at this height is estimated as ~ 0.9 G. Extrapolation of magnetic field strength to the inner corona gives ~ 10 G at the height of 0.1 R0. Radio observations can be successfully used for the sounding of the outer solar corona, where EUV observations of coronal loops fail

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

    NASA Astrophysics Data System (ADS)

    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

  8. Seismology in the United States, 1983-1986 (Paper 7R0264)

    NASA Astrophysics Data System (ADS)

    Hanks, Thomas C.

    1987-07-01

    Any seismologist trying even to carry, let alone read, the EOS abstract volumes for recent AGU Meetings knows full well of the substantial growth in seismological research during this reporting period, the four years of 1983 through 1986. Indeed, the number of Seismology Section abstracts has grown from 188 (Fall, 1982) to about 320 (Fall, 1986), to be more or less precise. At a time when research monies seem to be no better than stable (and declining in real terms) and when job opportunities for seismologists seem to have never been worse, at least in the professional lifetimes of most of us, something must be amiss, but certainly this is not the great vitality and diversity in seismological research during the past four years. The current reporting period saw the consortium approach brought to full flower in several fields of seismology, and these include CALCRUST, a consortium of California universities to investigate the crustal structure of the southwestern United States with seismic reflection data; DOSECC (Deep Observation and Sampling of the Earth's Continental Crust), a consortium to drill and make measurements within scientifically dedicated deep holes to sample active processes that make and remake the continents; EDGE, a consortium of university, government, and private industry scientists intent on exploring the oceanic/continental transitions along U.S. continental margins, using seismic and potential field methods; and IRIS (Incorporated Research Institutions for Seismology), whose prospectus includes a major upgrading of the global seismic network, an advanced portable array of 1000 seismic units for a host of active and passive experiments, and a data management center to store and utilize the vast quantities of data forthcoming from the first two activities. Each of these fledglings can trace their basic nature and motivation, if not their specific scientific agendas, to COCORP (Consortium for Continental Reflection Profiling), now a teenager

  9. Forensic Seismology and the Comprehensive Nuclear-Test-Ban Treaty

    NASA Astrophysics Data System (ADS)

    Bowers, David; Selby, Neil D.

    2009-05-01

    One application of forensic seismology is to help verify compliance with the Comprehensive Nuclear-Test-Ban Treaty. One of the challenges facing the forensic seismologist is to discriminate between the many thousands of earthquakes of potential interest each year and potential Treaty violations (underground explosions). There are four main methods: (a) ratio of body- to surface-wave magnitudes, (b) ratio of high-frequency P to S energy, (c) model-based methods, and (d) source depth. Methods (a) and (b) have an empirical basis. The weakness of methods (a)-(c) is the lack of an equivalent elastic source for an underground explosion fired in the range of geological media found around the world. Reliable routine source-depth determination has proved difficult. However, experience gained in the past decade at identifying suspicious seismic sources suggests that although no single method works all of the time, intelligent and original application of complementary methods is usually sufficient to satisfactorily identify the source in question.

  10. CSDP: The seismology of continental thermal regimes

    SciTech Connect

    Aki, K.

    1990-05-01

    This is a progress report for the past one year of research (year 3 of 5-year project) under the project titled CSDP: Seismology of Continental Thermal Regime'', in which we proposed to develop seismological interpretation theory and methods applicable to complex structures encountered in continental geothermal areas and apply them to several candidate sites for the Continental Scientific Drilling Project. The past year has been extremely productive especially in the area of interpretation theory, including the following two major break-throughs. One is the derivation of an integral equation for time-dependent power spectra, which unified all the existing theories on seismic scattering (including the radiative transfer theory for total energy and single and multiple scattering theories based on the ray approach) and offers more complete and economical solutions to the problems of seismic scattering and attenuation. The other is the new formula for synthetic seismograms for layered media with irregular interfaces, combining the T-matrix method for an arbitrary shaped inclusion and the method of global generalized reflection/transmission coefficients for layered media. Both breakthroughs will enable us to deal with seismic observations in complex earth structures more efficiently and accurately. In the area of experimental studies, we discovered seismic guided waves trapped in the San Andreas fault near Parkfield, California. 54 refs., 14 figs.

  11. Seismological Applications of the Stockwell Transform

    NASA Astrophysics Data System (ADS)

    Yedlin, M. J.; Ben Horin, Y.; Fraser, J. D.

    2012-04-01

    Time-frequency analysis has a long history in seismology, beginning with the use of the Hilbert Transform for computing seismic pulse distortion (Choy and Richards 1975) of teleseismic events and for computing the instantaneous phase and frequency in exploration seismology (Taner, Koehler and Sheriff, 1979). In the early 1990's computational algorithms shifted away from Fourier based time-frequency techniques to wavelet-based methods, introduced by Daubechies (1988, 1990). more recently a variant of the continuous wavelet transform, the Stockwell transform was developed by Stockwell, Mansinha and Lowe (1996) and converted to a dyadic representation in a very general setting by Brown, Lauzon and Frayne (2010). This generalized version of the Stockwell transform we shall refer to as the GST. In this presentation we will apply the GST in two different ways. First we will show how the GST can be used as a possible discriminant between controlled quarry blasts set off in the Negev and earthquakes. The GST analysis clearly demonstrates the impulsive character of the controlled blasts. A second application focuses on using the GST as a frequency-based travel-time picker. This application will compare the travel-time picks obtained using the first moment of the GST with those obtained using the instantaneous frequency computed via the analytic signal. The second application demonstrates the robustness of the GST-based travel-time picker, which does not have the stability issues inherent in the computation of the derivative of the instantaneous phase of the analytic signal.

  12. The nature of moss and lower atmospheric seismology.

    PubMed

    De Pontieu, B; Erdélyi, R

    2006-02-15

    The discovery of so-called solar 'moss', i.e. dynamic and bright upper transition region emission at chromospheric heights above active region plage, provides a novel diagnostic to probe the structure, dynamics, energetics and coupling of the magnetized solar chromosphere and transition region. We briefly review observations of the morphology and connectivity in the low solar atmosphere, with a particular focus on the propagation of oscillations and waves in the moss. We also present recent work that combines moss observations and numerical modelling, and which sheds light on the (quasi-periodic) formation of dynamic jets (spicules), and the propagation of normally evanescent oscillations into the corona. We also briefly explore how coronal oscillations could be exploited to determine the connectivity between photosphere and corona, i.e. perform seismology of the lower solar atmosphere. PMID:16414885

  13. Global Federation of Data Services in Seismology: Extending the Concept to Interdisciplinary Science

    NASA Astrophysics Data System (ADS)

    Ahern, Tim; Trabant, Chad; Stults, Mike; VanFossen, Mick

    2016-04-01

    The International Federation of Digital Seismograph Networks (FDSN) sets international standards, formats, and access protocols for global seismology. Recently the availability of an FDSN standard for web services has enabled the development of a federated model of data access. With a growing number of internationally distributed data centers supporting compatible web services the task of federation is now fully realizable. The utility of this approach is already starting to bear fruit in seismology. This presentation will highlight the advances the seismological community has made in the past year towards federated access to seismological data including waveforms, earthquake event catalogs, and metadata describing seismic stations. It will include a discussion of an IRIS Federator as well as an emerging effort to develop an FDSN Federator that will allow seamless access to seismological information across multiple FDSN data centers. As part of the NSF EarthCube initiative as well as the US-European data coordination project (COOPEUS), IRIS and several partners, collectively called GeoWS, have been extending the concept of standard web services to other domains. Our primary partners include Lamont Doherty Earth Observatory (marine geophysics), Caltech (tectonic plate reconstructions), SDSC (hydrology), UNAVCO (geodesy), and Unidata (atmospheric sciences). Additionally, IRIS is working with partners at NOAA's National Centers for Environmental Information (NCEI) , NEON, UTEP, WOVOdat, INTERMAGNET, Global Geodynamics Program, and the Ocean Observatory Initiative (OOI) to develop web services for those domains. The ultimate goal is to allow discovery, access, and utilization of cross-domain data sources. One of the significant outcomes of this effort is the development of a simple text and metadata representation for tabular data called GeoCSV, that allows straightforward interpretation of information from multiple domains by non-domain experts.

  14. The 2015, Mw 6.5, Leucas (Ionian Sea, Greece) earthquake: Seismological and Geodetic Modelling

    NASA Astrophysics Data System (ADS)

    Saltogianni, Vasso; Taymaz, Tuncay; Yolsal-Çevikbilen, Seda; Eken, Tuna; Moschas, Fanis; Stiros, Stathis

    2016-04-01

    A cluster of earthquakes (6active region in Greece, in the last 30 years. The most recent earthquake was the 2015 (Mw 6.5) Leucas (Lefkada) earthquake. The modelling of these earthquakes, some of which are double events (2003 Leucas; 2014 Cephalonia) is a challenge for two main reasons. First, the geography of the area limits the distribution of the available seismological and GNSS stations and the correlations of INSAR data. Second, the structural pattern of the area indicates distributed thrusting but recent earthquakes are confined to the west margin of the Aegean Arc, usually assigned to the Cephalonia Transform Fault (CTF), and are dominated by strike slip faulting. In order to contribute to the understanding active tectonics along this critical region, our study was based on the independent analysis of the seismological and geodetic signature of the 2015 earthquake and the on the joint evaluation of the inferred models on the basis of the fault pattern of the area and of previous earthquakes. First, based on teleseismic long-period P- and SH- and broad-band P-waveforms a point-source solution at the SW part of Leucas yielded dominantly right-lateral strike-slip faulting mechanisms (strike: 23o, dip: 68o, rake: -170o) with a shallow focal depth (h: 9 km) and with seismic moment of Mo: 10.4x1018 Nm. Furthermore, the rupture history of the earthquake was obtained by applying a new back-projection method that uses teleseismic P-waveforms to integrate the direct P-phase with reflected phases from structural discontinuities near the source. In the slip inversion the faulting occurs on a single fault plane (strike and dip are obtained from the best fitting point-source solution) and slip (rake) angle varied during the whole rupture process. Second, co-seismic displacements were derived from eight permanent and one campaign GPS

  15. Bulgarian Seismological and GPS/GNSS networks-current status and practical implementation

    NASA Astrophysics Data System (ADS)

    Solakov, Dimcho; Simeonova, Stela; Georgiev, Ivan; Dimitrova, Lilia; Slavcheva, Krasimira; Raykova, Plamena

    2016-04-01

    responsible governmental authorities if necessary urgent activities to be undertaken. The available infrastructure - permanent GNSS stations, spread all over the country allow performing permanent monitoring of the Earth's crust movements on the basis of the obtained velocities of the permanent stations and the time series with their coordinates. Additional information for the current movements is obtained by the processing and analysis of the regular GNSS measurements of geodynamic network. In the GNSS Analysis Center are acquired, processed and analyzed data from more than 70 permanent stations on Bulgarian territory. In the analysis are included also data from permanent stations on the Balkan Peninsula and from the European Permanent Network. Along with the seismological and geological information, the quantitative assessment of the movements of the Earth's crust is of the substantial importance for monitoring of the active tectonic structures and is the base for the seismic hazard assessment.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    community. It enables active researchers to invent and refine scalable methods for innovative statistical analysis of seismic waveforms in a wide range of application contexts. The VRE paves the way towards a flexible shared framework for seismic waveform inversion, lowering the barriers to uptake for the next generation of researchers. The VRE can be accessed through the science gateway that puts together computational and data-intensive research into the same framework, integrating multiple data sources and services. It provides a context for task-oriented and data-streaming workflows, and maps user actions to the full gamut of the federated platform resources and procurement policies, activating the necessary behind-the-scene automation and transformation. The platform manages and produces domain metadata, coupling them with the provenance information describing the relationships and the dependencies, which characterise the whole workflow process. This dynamic knowledge base, can be explored for validation purposes via a graphical interface and a web API. Moreover, it fosters the assisted selection and re-use of the data within each phase of the scientific analysis. These phases can be identified as Simulation, Data Access, Preprocessing, Misfit and data processing, and are presented to the users of the gateway as dedicated and interactive workspaces. By enabling researchers to share results and provenance information, VERCE steers open-science behaviour, allowing researchers to discover and build on prior work and thereby to progress faster. A key asset is the agile strategy that VERCE deployed in a multi-organisational context, engaging seismologists, data scientists, ICT researchers, HPC and data resource providers, system administrators into short-lived tasks each with a goal that is a seismology priority, and intimately coupling research thinking with technical innovation. This changes the focus from HPC production environments and community data services to user

  17. Seismicity location from analysis of a 2 years passive seismological experiment around Ulaanbaatar

    NASA Astrophysics Data System (ADS)

    Batkhuu, Battulga; Munkhuu, Ulziibat; Sebe, Olivier; Monfret, Tony; Deschamps, Anne; Gao, Mengtan; Wu, Qingju

    2014-05-01

    We analyse broadband seismological records from a 2 years temporary array deployed over a 400x600km2 region in central Mongolia, including Ulaanbaatar region, by a Sino-Mongolian cooperation. The dataset is completed with all available regional data, mostly recorded by Mongolian National Seismic Network (MNSN) operated by Research Center for Astronomy and Geophysics (RCAG). The seismic activity of the covered area is not very high, except SW of Ulaanbaatar. To obtain as good as possible image of this seismicity, we have first to determine a regional velocity model. The development of mining activity in Mongolia, allows us to record a large set of quarry blasts. Due to the very continental position of Mongolia, micro-seismic noise level is low and the signal of these human made sources are very often recorded at distances as far as 200km. Travel time information of direct, reflected and refracted waves are used to produce crustal information (Moho depth and mean crustal P wave velocity, and velocity below the Moho, Vp/Vs ratio) over the area of observation. We show that the crust of the studied area is relatively homogeneous which allows us to improve this very simple model, searching the best crustal model with Velest software. The experiment was supported by Sino-Mongolian joint project titled "The Geophysical Investigation and Deep Structure Modeling for Seismic Hazard Assessment in the Far East", Project code: 2011DFB20120.

  18. Suggested notation conventions for rotational seismology

    USGS Publications Warehouse

    Evans, J.R.

    2009-01-01

    We note substantial inconsistency among authors discussing rotational motions observed with inertial seismic sensors (and much more so in the broader topic of rotational phenomena). Working from physics and other precedents, we propose standard terminology and a preferred reference frame for inertial sensors (Fig. 1) that may be consistently used in discussions of both finite and infinitesimal observed rotational and translational motions in seismology and earthquake engineering. The scope of this article is limited to observations because there are significant differences in the analysis of finite and infinitesimal rotations, though such discussions should remain compatible with those presented here where possible. We recommend the general use of the notation conventions presented in this tutorial, and we recommend that any deviations or alternatives be explicitly defined.

  19. Outstanding challenges in the seismological study of volcanic processes: Results from recent U.S. and European community-wide discussion workshops

    NASA Astrophysics Data System (ADS)

    Roman, D. C.; Rodgers, M.; Mather, T. A.; Power, J. A.; Pyle, D. M.

    2014-12-01

    Observations of volcanically induced seismicity are essential for eruption forecasting and for real-time and near-real-time warnings of hazardous volcanic activity. Studies of volcanic seismicity and of seismic wave propagation also provide critical understanding of subsurface magmatic systems and the physical processes associated with magma genesis, transport, and eruption. However, desipite significant advances in recent years, our ability to successfully forecast volcanic eruptions and fully understand subsurface volcanic processes is limited by our current understanding of the source processes of volcano-seismic events, the effects on seismic wave propagation within volcanic structures, limited data, and even the non-standardized terminology used to describe seismic waveforms. Progress in volcano seismology is further hampered by inconsistent data formats and standards, lack of state-of-the-art hardware and professional technical staff, as well as a lack of widely adopted analysis techniques and software. Addressing these challenges will not only advance scientific understanding of volcanoes, but also will lead to more accurate forecasts and warnings of hazardous volcanic eruptions that would ultimately save lives and property world-wide. Two recent workshops held in Anchorage, Alaska, and Oxford, UK, represent important steps towards developing a relationship among members of the academic community and government agencies, focused around a shared, long-term vision for volcano seismology. Recommendations arising from the two workshops fall into six categories: 1) Ongoing and enhanced community-wide discussions, 2) data and code curation and dissemination, 3) code development, 4) development of resources for more comprehensive data mining, 5) enhanced strategic seismic data collection, and 6) enhanced integration of multiple datasets (including seismicity) to understand all states of volcano activity through space and time. As presented sequentially above, these

  20. Advanced Light Source Activity Report 2002

    SciTech Connect

    Duque, Theresa; Greiner, Annette; Moxon, Elizabeth; Robinson, Arthur; Tamura, Lori

    2003-06-12

    This annual report of the Advanced Light Source details science highlights and facility improvements during the year. It also offers information on events sponsored by the facility, technical specifications, and staff and publication information.

  1. The Era of Computational Seismology (Beno Gutenberg Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Tromp, Jeroen

    2013-04-01

    The quality of tomographic images of the Earth's interior and earthquake source models is closely tied to our ability to efficiently and accurately simulate 3D seismic wave propagation. For decades seismologists have used asymptotic, approximate methods to address the forward problem in seismology, namely, given a seismic source and a 3D Earth model, accurately simulate the associated wave motions. In recent years, modern numerical methods and parallel computers have facilitated fully 3D simulations of seismic wave propagation at unprecedented resolution and accuracy, heralding the age of computational seismology. The current focus is on harnessing the power of these sophisticated forward modeling tools to enhance the quality of images of the Earth's interior and the earthquake rupture process, that is, to address the inverse problem. Traditional tomographic methods utilize traveltime and dispersion information obtained by comparing data with simulations, and interpret such measurements based on ray theory or other approximate methods. Because of the limitations of these approximate techniques, only certain parts of seismograms can be used, and initial models are generally restricted to be layered or spherically symmetric. With modern numerical modeling tools we are now going well beyond classical tomography, using fully 3D initial models and utilizing as much information contained in seismograms as possible. The ultimate goal is broad band full waveform inversion utilizing entire seismograms. Surprisingly, one tomographic iteration may be performed based on just two numerical simulations for each earthquake: one calculation for the current model and a second 'adjoint' calculation that uses time-reversed signals at the receivers as simultaneous, fictitious sources. Seismic imaging based on adjoint methods assimilates seismographic information into 3D models of elastic (seismic wavespeeds) and anelastic (quality factors) structure. These methods fully account for

  2. National Synchrotron Light Source 2010 Activity Report

    SciTech Connect

    Rowe, M.; Snyder, K. J.

    2010-12-29

    This is a very exciting period for photon sciences at Brookhaven National Laboratory. It is also a time of unprecedented growth for the Photon Sciences Directorate, which operates the National Synchrotron Light Source (NSLS) and is constructing NSLS-II, both funded by the Department of Energy's Office of Science. Reflecting the quick pace of our activities, we chose the theme 'Discovery at Light Speed' for the directorate's 2010 annual report, a fiscal year bookended by October 2009 and September 2010. The year began with the news that NSLS users Venki Ramakrishnan of Cambridge University (also a former employee in Brookhaven's biology department) and Thomas A. Steitz of Yale University were sharing the 2009 Nobel Prize in Chemistry with Ada E. Yonath of the Weizmann Institute of Science. Every research project has the potential for accolades. In 2010, NSLS users and staff published close to 900 papers, with about 170 appearing in premiere journals. Those are impressive stats for a facility nearly three decades old, testament to the highly dedicated team keeping NSLS at peak performance and the high quality of its user community. Our NSLS users come from a worldwide community of scientists using photons, or light, to carry out research in energy and environmental sciences, physics, materials science, chemistry, biology and medicine. All are looking forward to the new capabilities enabled by NSLS-II, which will offer unprecedented resolution at the nanoscale. The new facility will produce x-rays more than 10,000 times brighter than the current NSLS and host a suite of sophisticated instruments for cutting-edge science. Some of the scientific discoveries we anticipate at NSLS-II will lead to major advances in alternative energy technologies, such as hydrogen and solar. These discoveries could pave the way to: (1) catalysts that split water with sunlight for hydrogen production; (2) materials that can reversibly store large quantities of electricity or hydrogen; (3

  3. Ehmmanuil Dyudvigovich Nobel' i Rossijskaya astronomiya i sejsmologiya %t Emanuel Ludvigovich Nobel and astronomy and seismology in Russia

    NASA Astrophysics Data System (ADS)

    Meshkunov, V. S.; Mikisha, A. M.

    This paper deals with the Nobel family activity in the promotion of astronomy and seismology in Russia. The family members paid special attention to the development of the oil fields in Caspian region which made regularly seismological observations necessary. Two famous Russian scientists, O. Baklund and B. Golitsyn, were involved in this activity. Specific role in this cooperation belonged to German firm "Repsold & Sons". The authors use archival data found in St.-Petersburg Department of the Archives of RAS and in the archives of Hamburg as well as rare publications in Russian and German press of the end of the 19th - beginning of the 20th centuries.

  4. Recent negative ion source activity at JYFL

    NASA Astrophysics Data System (ADS)

    Kalvas, T.; Tarvainen, O.; Komppula, J.; Laitinen, M.; Sajavaara, T.; Koivisto, H.; Jokinen, A.; Dehnel, M. P.

    2013-02-01

    A filament-powered multicusp ion source for production of H- has been developed for the Jyväskylä Pelletron accelerator for use in ion beam lithography and particle induced X-ray emission applications. The source can be considered conventional with the exception of the filter field being created with an electric magnet for continuous adjustability. A permanent magnet dipoleantidipole electron dump is integrated in the puller electrode. The source provides 50 μA H- beam at 10 keV energy with 0.019 mm mrad 95 % normalized rms emittance through a 2 mm aperture. Lower emittance is achievable by changing the plasma electrode insert to a smaller aperture one if application requires. A new commercial MCC30/15 cyclotron has been installed at the Jyväskylä accelerator laboratory providing 30MeV H+ and 15Mev D+ for use in nuclear physics experiments and applications. The ion source delivered with the cyclotron is a a filament-powered multicusp source capable of about 130 h continuous operation at 1 mA H- output between filament changes. The ion source is located in the cyclotron vault and therefore a significant waiting time for the vault cooldown is required before filament change is possible. This kind of operation is not acceptable as 350 h and longer experiments are expected. Therefore a project for developing a CW 13.56 MHz RF ion source has been initiated. A planar RF antenna replacing the filament back plate of the existing TRIUMF-type ion source has been used in the first tests with 240 μA of H- and 21 mA of electrons measured at 1.5 kW of RF power. Tests with higher RF power levels were prevented by electron beam induced sparking. A new plasma chamber has been built and a new extraction is being designed for the RF ion source. The extraction code IBSimu has recently gone through a major update on how smooth electrode surfaces are implemented in the Poisson solvers. This has made it possible to implement a fast multigrid solver with low memory consumption. Also

  5. A preliminary analysis of seismological techniques to study Eros and other asteroids

    NASA Astrophysics Data System (ADS)

    Walker, James D.; Sagebiel, Erick J.; Huebner, Walter F.

    The NEAR Shoemaker mission to near-Earth asteroid 433 Eros provided a great deal of information about the asteroid. Still to be learned are the interior structure and material properties: the local density, strength, and cohesiveness within Eros. Seismology is a way to determine such information. This paper numerically explores performing a seismological experiment on Eros, using an explosive as a seismic source. Computations with the explosive source were performed in an Eulerian hydrocode (CTH) and then results of those computations were transferred to a Lagrangian wavecode (LS-DYNA) to calculate the subsequent seismic wave propagation in the body. To verify the technique, computations were first carried out for two cases where analytical results are known: a uniaxial-strain bar and a sphere. Computations were then performed for a three-dimensional solid model of Eros with surface shape based on NEAR data. Initial computations assumed Eros was isotropic and homogeneous in its material properties. Modal frequency computations for the isotropic, homogeneous Eros were then compared with a model of Eros that included an interior fracture plane. Differences in seismic traces and in modal frequencies show that seismology can differentiate the interior of Eros in particular and other asteroids in general.

  6. NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 1998.

    SciTech Connect

    ROTHMAN,E.

    1999-05-01

    In FY 1998, following the 50th Anniversary Year of Brookhaven National Laboratory, Brookhaven Science Associates became the new Managers of BNL. The new start is an appropriate time to take stock of past achievements and to renew or confirm future goals. During the 1998 NSLS Annual Users Meeting (described in Part 3 of this Activity Report), the DOE Laboratory Operations Board, Chaired by the Under Secretary for Energy, Ernest Moniz met at BNL. By chance all the NSLS Chairmen except Martin Blume (acting NSLS Chair 84-85) were present as recorded in the picture. Under their leadership the NSLS has improved dramatically: (1) The VUV Ring current has increased from 100 mA in October 1982 to nearly 1 A today. For the following few years 10 Ahrs of current were delivered most weeks - NSLS now exceeds that every day. (2) When the first experiments were performed on the X-ray ring during FY1985 the electron energy was 2 GeV and the current up to 100 mA - the X-Ray Ring now runs routinely at 2.5 GeV and at 2.8 GeV with up to 350 mA of current, with a very much longer beam half-life and improved reliability. (3) Starting in FY 1984 the proposal for the Phase II upgrade, mainly for a building extension and a suite of insertion devices and their associated beamlines, was pursued - the promises were delivered in full so that for some years now the NSLS has been running with two undulators in the VUV Ring and three wigglers and an undulator in the X-Ray Ring. In addition two novel insertion devices have been commissioned in the X13 straight. (4) At the start of FY 1998 the NSLS welcomed its 7000th user - attracted by the opportunity for pursuing research with high quality beams, guaranteed not to be interrupted by 'delivery failures', and welcomed by an efficient and caring user office and first class teams of PRT and NSLS staff. R & D have lead to the possibility of running the X-Ray Ring at the higher energy of 2.8 GeV. Figure 1 shows the first user beam, which was provided

  7. Fast Magnetosonic Waves and Global Coronal Seismology in the Extended Solar Corona

    NASA Astrophysics Data System (ADS)

    Kwon, Ryun Young; Zhang, J.; Kramar, M.; Wang, T.; Ofman, L.; Davila, J. M.

    2013-07-01

    We present global coronal seismology, for the first time, that allows us to determine inhomogeneous magnetic field strengths in a wide range of the extended solar corona. We use observations of propagating disturbance associated with a coronal mass ejection observed on 2011 August 4 by the COR1 inner coronagraphs on board the STEREO spacecraft. We establish that the disturbance is in fact a fast magnetosonic wave as the upper coronal counterpart of the EIT wave observed by STEREO EUVI and travels across magnetic field lines with inhomogeneous speeds, passing through various coronal regions such as quiet/active corona, coronal holes, and streamers. We derive magnetic field strengths along the azimuthal trajectories of the fronts at heliocentric distances 2.0, 2.5, and 3.0 Rs, using the varying speeds and electron densities. The derived magnetic field strengths are consistent with values determined with a potential field source surface model and reported in previous works. The ranges of the magnetic field strengths at these heliocentric distances are 0.44 ± 0.29, 0.23 ± 0.15, and 0.26 ± 0.14 G, respectively. The uncertainty in determining magnetic field strengths is about 40 %. This work demonstrates that observations of fast magnetosonic waves by white-light coronagraphs can provide us with a unique way to diagnose magnetic field strength of an inhomogeneous medium in a wide spatial range of the extended solar corona.

  8. NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 2004

    SciTech Connect

    MILLER,L.

    2005-05-01

    for the environmental science community, is also very important, as it will help to satisfy the large over subscription rate for this technique at the NSLS. Two other important upgrades that were initiated this past year are the replacement of the X25 wiggler with an undulator and the construction of the X9 undulator beamline for small-angle scattering, with an emphasis on nanoscience research. Another key activity that will benefit all users was the restoration of the x-ray ring lattice symmetry, which reduced the horizontal emittance and made the operational lattice more robust. Similarly, all users will benefit from the introduction of the PASS (Proposal Allocation Safety Scheduling) system this past year, which has greatly improved the process of proposal submission, review, allocation, and scheduling. This coming year we will work to add Rapid Access to the capabilities of PASS. Overall, the success of these and the many other projects that space does not permit listing is a testament to the dedication, hard work, and skill of the NSLS staff. Safety has always been an important issue at a large, complex scientific facility like the NSLS and in 2004 it received renewed attention. Safety is our highest priority and we spent a great deal of time reviewing and refining our safety practices and procedures. A new 'Safety Highlights' web page was created for safety news, and a large number of safety meetings and discussions were held. These reviews and meetings generated many ideas on how the NSLS might improve its safety practices, and we are committed to putting these in place and improving our already very good safety program. We had no lost-time accidents in 2004, which is a notable accomplishment. Our goal is to be best in class and I'm confident that by working together we can achieve that status. Several activities took place this past year to advance our proposal to replace the NSLS with a new National Synchrotron Light Source-II facility. These included a major

  9. STSHV a teleinformatic system for historic seismology in Venezuela

    NASA Astrophysics Data System (ADS)

    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

  10. Data Democracy in Simultaneous Monte Carlo Optimizations of Geodetic and Seismological Data

    NASA Astrophysics Data System (ADS)

    Sudhaus, H.; Heimann, S.

    2012-04-01

    Estimating the geometry of an earthquake source from seismological and/or geodetic data is a non-linear problem. Often, Monte Carlo optimizations methods are used to find the optimum earthquake model through a clever sampling of the misfit function in the multidimensional model space. The topology of the misfit function, however, very much depends on the data weights we assign. Consequently, also the best fitting model is influenced by the choice of data weights. Data weighting in general is commonly applied these days. Still, there is a large variation between simple arbitrary data weight assignments and weights calculated from estimated data error estimations or trial modeling results. In geodetic source modeling, an accepted and regularly applied procedure is to weight the data, e. g. GPS and InSAR data, according to their quality by using the data error variance-covariance matrix. In this way, we consider correlations of densely spaced data and the data weight factors are independent of the model parametrization. In seismological source studies, the data weighting often appears to be done in a more simple manner. Qualitatively, the azimuthal coverage is taken care of and only sometimes relative weights for different stations are assigned, e. g. based on apparent noise. In a combination of geodetic and seismological data a common rationale for finding the weights would be desirable and moreover we need to find meaningful weighting between the data of different nature, like seismological and GPS data. We present such data weighting in a case study on the 2010 Haiti earthquake to test whether this improves a combined optimization of seismological and geodetic data. For the fault that ruptured during the 2010 Haiti earthquake there are so far at least four different published fault slip models. And, as is often the case, these four are not easily comparable because (1) each model differs from the other to some extent with respect to the model parametrization and

  11. Seismological evidence of an active footwall shortcut thrust in the Northern Itoigawa-Shizuoka Tectonic Line derived by the aftershock sequence of the 2014 M 6.7 Northern Nagano earthquake

    NASA Astrophysics Data System (ADS)

    Panayotopoulos, Yannis; Hirata, Naoshi; Hashima, Akinori; Iwasaki, Takaya; Sakai, Shin'ichi; Sato, Hiroshi

    2016-06-01

    A destructive M 6.7 earthquake struck Northern Nagano prefecture on November 22, 2014. The main shock occurred on the Kamishiro fault segment of the northern Itoigawa-Shizuoka Tectonic Line (ISTL). We used data recorded at 41 stations of the local seismographic network in order to locate 2118 earthquakes that occurred between November 18 and November 30, 2014. To estimate hypocenters, we assigned low Vp models to stations within the Northern Fossa Magna (NFM) basin thus accounting for large lateral crustal heterogeneities across the Kamishiro fault. In order to further improve accuracy, the final hypocenter locations were recalculated inside a 3D velocity model using the double-difference method. We used the aftershock activity distribution and focal mechanism solutions of major events in order to estimate the source fault area of the main shock. Our analysis suggests that the shallow part of the source fault corresponds to the surface trace of the Kamishiro fault and dips 30°-45° SE, while the deeper part of the source fault corresponds to the downdip portion of the Otari-Nakayama fault, a high angle fault dipping 50°-65° SE that formed during the opening of the NFM basin in the Miocene. Along its surface trace the Otari-Nakayama fault has been inactive during the late Quaternary. We verified the validity of our model by calculating surface deformation using a simple homogeneous elastic half-space model and comparing it to observed surface deformation from satellite interferometry, assuming large coseismic slip in the areas of low seismicity and small coseismic slip in the areas of high seismicity. Shallowing of the source fault from 50°-65° to 30°-45° in the upper 4 km, in the areas where both surface fault traces are visible, is a result of footwall shortcut thrusting by the Kamishiro fault off the Otari-Nakayama fault.

  12. Saturn Ring Seismology: Interpreting the Seismogram

    NASA Technical Reports Server (NTRS)

    Marley, Mark Scott

    2013-01-01

    Marley (1990) and Marley and Porco (1993) proposed that f-mode oscillations of Saturn could excite resonant density and bending waves in the inner C-ring. They hypothesized that certain wave features discovered by Rosen et al. (1991) that were not associated with known satellite resonances could be the result of such resonant interactions with the planetary oscillation modes. They also predicted that if this was the case the waves would be found to be density (and not bending) waves by Cassini and predicted the azimuthal wave number of the C-ring waves m. Employing Cassini VIMS stellar occultation data Hedman and Nicholson (2013) have now confirmed the predictions and demonstrated that at least some of the C-ring features identified by Rosen et al. are indeed likely caused by resonant oscillation modes of Saturn. Given this context we have taken a fresh look at the Saturn ring seismology. First we propose that an apparent bending wave denoted 'j' by Rosen may be a second order outer vertical resonance with the l=3, m=2 f-mode of Saturn and discuss the locations of other plausible second order resonances in the rings. Since only a handful of ring resonances have been identified, measuring even one or two additional planetary mode frequencies would substantially assist the process of inverting mode frequencies to constrain Saturn interior's structure. Using the available mode frequencies, modern inversion technique employed in stellar seismology, and a recent set of Saturn interior models we provide an initial estimation of what available mode frequencies are telling us about the interior structure of the planet. Since the f-modes are confined relatively closely to the planetary surface, most of the observed modes probe only the outermost layers of the planet that are already comparatively well understood. However the l = 2 mode does probe relatively deeply into the planet and we will discuss the potential the measurement of this mode frequency has for placing new

  13. Weak Elastic Anisotropy in Global Seismology

    NASA Astrophysics Data System (ADS)

    Thomsen, L.; Anderson, D. L.

    2014-12-01

    Most of the major features of the Earth's interior were discovered using the concepts of isotropic seismology; however, subtle features require more realistic concepts. Although the importance of anisotropy has been known for over 50 years, only in the last decade has the increasing quality and quantity of data forced the wide recognition that anisotropyis crucial for accurate descriptions of upper mantle structure. The persistence of the "plume hypothesis", in spite of abundant evidence to the contrary, is partly based on the neglect of anisotropy, sparse and biased ray coverage, and the misuse of Occam's razor. Whereas isotropic inversion of teleseismic near-vertical travel-time datasets suggests the presence of deep vertical zones of low velocity (interpreted as mantle plumes), anisotropic inversion of data having a range of polarizations and directions of approach suggests instead shallow zones of relatively high anisotropy. This raises the possibility that current understanding of manyof the subtle features of Earth structure could be erroneous, caused by over-simplified analysis. The simplest plausible anisotropic model is that of polar anisotropy ("VTI" [sic!]), with a radial symmetry axis. The essential idea which makes anisotropic seismology feasible is the recognition that, in the Earth, the anisotropy is almost invariably weak, and the anisotropic equations (linearized in appropriately chosen small parameters) are quite simple (see below). These equations show that, to first order, the anisotropic variation of velocity is not governed by the individual Cab , but rather by the combinations of parameters given above. Hence, inversions should seek these combinations, rather than the individual moduli. The Rayleigh velocity VR is a simple function of VS0 and the P- and SV- anisotropies. The Love velocity VL is a complicated function of VS0 and the SH anisotropy γ. The simplest plausible model of azimuthal anisotropy is orthorhombic (not ("HTI" [sic

  14. a Collaborative Cyberinfrastructure for Earthquake Seismology

    NASA Astrophysics Data System (ADS)

    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

  15. Wysession begins term as Eos Section Editor for Seismology

    NASA Astrophysics Data System (ADS)

    Wysession, Michael

    In mid-April, Michael Wysession, an associate professor in the Department of Earth and Planetary Sciences at Washington University, embarked on a 3-year term as section editor of Eos for seismology. Wysession brings to the position a strong background in research and teaching. Below are a few remarks from Wysession.“I recently became the new seismology editor for Eos. I look forward to presenting the many exciting areas of seismological research to the entire geophysical community. I have taught at Washington University since obtaining my Ph.D. at Northwestern University in 1991. My interest in seismology began during my undergraduate years at Brown University (Sc.B., 1984), but my experience as an educator began after I graduated and taught high school math and physics in Staten Island, N.Y.

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

    NASA Astrophysics Data System (ADS)

    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

  17. Active Control of Aerodynamic Noise Sources

    NASA Technical Reports Server (NTRS)

    Reynolds, Gregory A.

    2001-01-01

    Aerodynamic noise sources become important when propulsion noise is relatively low, as during aircraft landing. Under these conditions, aerodynamic noise from high-lift systems can be significant. The research program and accomplishments described here are directed toward reduction of this aerodynamic noise. Progress toward this objective include correction of flow quality in the Low Turbulence Water Channel flow facility, development of a test model and traversing mechanism, and improvement of the data acquisition and flow visualization capabilities in the Aero. & Fluid Dynamics Laboratory. These developments are described in this report.

  18. Chemical and seismological constraints on mantle heterogeneity.

    PubMed

    Helffrich, George

    2002-11-15

    Recent seismological studies that use scattered waves to detect heterogeneities in the mantle reveal the presence of a small, distributed elastic heterogeneity in the lower mantle which does not appear to be thermal in nature. The characteristic size of these heterogeneities appears to be ca. 8 km, suggesting that they represent subducted recycled oceanic crust. With this stimulus, old ideas that the mantle is heterogeneous in structure, rather than stratified, are reinterpreted and a simple, end-member model for the heterogeneity structure is proposed. The volumetrically largest components in the model are recycled oceanic crust, which contains the heat-producing elements, and mantle depleted of these and other incompatible trace elements. About 10% of the mantle's mass is made up of recycled oceanic crust, which is associated with the observed small-scale seismic heterogeneity. The way this heterogeneity is distributed is in convectively stretched and thinned bodies ranging downwards in size from 8 km. With the present techniques to detect small bodies through scattering, only ca. 55% of the mantle's small-scale heterogeneities are detectable seismically. PMID:12460477

  19. Ground Truth Accuracy Tests of GPS Seismology

    NASA Astrophysics Data System (ADS)

    Elosegui, P.; Oberlander, D. J.; Davis, J. L.; Baena, R.; Ekstrom, G.

    2005-12-01

    As the precision of GPS determinations of site position continues to improve the detection of smaller and faster geophysical signals becomes possible. However, lack of independent measurements of these signals often precludes an assessment of the accuracy of such GPS position determinations. This may be particularly true for high-rate GPS applications. We have built an apparatus to assess the accuracy of GPS position determinations for high-rate applications, in particular the application known as "GPS seismology." The apparatus consists of a bidirectional, single-axis positioning table coupled to a digitally controlled stepping motor. The motor, in turn, is connected to a Field Programmable Gate Array (FPGA) chip that synchronously sequences through real historical earthquake profiles stored in Erasable Programmable Read Only Memory's (EPROM). A GPS antenna attached to this positioning table undergoes the simulated seismic motions of the Earth's surface while collecting high-rate GPS data. Analysis of the time-dependent position estimates can then be compared to the "ground truth," and the resultant GPS error spectrum can be measured. We have made extensive measurements with this system while inducing simulated seismic motions either in the horizontal plane or the vertical axis. A second stationary GPS antenna at a distance of several meters was simultaneously collecting high-rate (5 Hz) GPS data. We will present the calibration of this system, describe the GPS observations and data analysis, and assess the accuracy of GPS for high-rate geophysical applications and natural hazards mitigation.

  20. Advanced Light Source: Activity report 1993

    SciTech Connect

    Not Available

    1994-11-01

    The Advanced Light Source (ALS) produces the world`s brightest light in the ultraviolet and soft x-ray regions of the spectrum. The first low-energy third-generation synchrotron source in the world, the ALS provides unprecedented opportunities for research in science and technology not possible anywhere else. This year marked the beginning of operations and the start of the user research program at the ALS, which has already produced numerous high quality results. A national user facility located at Lawrence Berkeley Laboratory of the University of California, the ALS is available to researchers from academia, industry, and government laboratories. This report contains the following: (1) director`s message; (2) operations overview; (3) user program; (4) users` executive committee; (5) industrial outreach; (6) accelerator operations; (7) beamline control system; (8) insertion devices; (9) experimental systems; (10) beamline engineering; (11) first results from user beamlines; (12) beamlines for 1994--1995; (13) special events; (14) publications; (15) advisory panels; and (16) ALS staff.

  1. Global Federation of Data Services in Seismology: Extending the Concept to Interdisciplinary Science

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    The International Federation of Digital Seismograph Networks (FDSN) sets international standards, formats, and access protocols for global seismology. Recently the availability of an FDSN standard for web services has enabled the development of a federated model of data access. With a growing number of internationally distributed data centers supporting identical web services the task of federation is now fully realizable. This presentation will highlight the advances the seismological community has made in the past year towards federated access to seismological data including waveforms, earthquake event catalogs, and metadata describing seismic stations. As part of the NSF EarthCube project, IRIS and its partners have been extending the concept of standard web services to other domains. Our primary partners include Lamont Doherty Earth Observatory (marine geophysics), Caltech (tectonic plate reconstructions), SDSC (hydrology), UNAVCO (geodesy), and Unidata (atmospheric sciences). Additionally IRIS is working with partners at NOAA's NGDC, NEON, UTEP, WOVODAT, Intermagnet, Global Geodynamics Program, and the Ocean Observatory Initiative (OOI) to develop web services for those domains. The ultimate goal is to allow discovery, access, and utilization of cross-domain data sources. IRIS and a variety of US and European partners have been involved in the Cooperation between Europe and the US (CoopEUS) project where interdisciplinary data integration is a key topic.

  2. Environmental seismology: What can we learn on earth surface processes with ambient noise?

    NASA Astrophysics Data System (ADS)

    Larose, Eric; Carrière, Simon; Voisin, Christophe; Bottelin, Pierre; Baillet, Laurent; Guéguen, Philippe; Walter, Fabian; Jongmans, Denis; Guillier, Bertrand; Garambois, Stéphane; Gimbert, Florent; Massey, Chris

    2015-05-01

    Environmental seismology consists in studying the mechanical vibrations that originate from, or that have been affected by external causes, that is to say causes outside the solid Earth. This includes for instance the coupling between the solid Earth and the cryosphere, or the hydrosphere, the anthroposphere and the specific sources of vibration developing there. Environmental seismology also addresses the modifications of the wave propagation due to environmental forcing such as temperature and hydrology. Recent developments in data processing, together with increasing computational power and sensor concentration have led to original observations that allow for the development of this new field of seismology. In this article, we will particularly review how we can track and interpret tiny changes in the subsurface of the Earth related to external changes from modifications of the seismic wave propagation, with application to geomechanics, hydrology, and natural hazard. We will particularly demonstrate that, using ambient noise, we can track 1) thermal variations in the subsoil, in buildings or in rock columns; 2) the temporal and spatial evolution of a water table; 3) the evolution of the rigidity of the soil constituting a landslide, and especially the drop of rigidity preceding a failure event.

  3. The Enlightenment Revisited: Sources & Interpretations. Learning Activities.

    ERIC Educational Resources Information Center

    Donato, Clorinda; And Others

    This resource book provides 26 learning activities with background materials for teaching about the Enlightenment. Topics include: (1) "What Was the Enlightenment?"; (2) "An Introduction to the Philosophes"; (3) "Was the Enlightenment a Revolt Against Rationalism?"; (4) "Were the Philosophes Democrats? A Comparison of the 'Enlightened' Ideas of…

  4. The central power source in active galaxies

    NASA Astrophysics Data System (ADS)

    Ptak, Roger; Stoner, Ronald

    Potential sources for the central power in AGN are examined. The continuum, emission line profiles, and time variability and broad emission line region for AGN are analyzed. The supermassive black hole hypothesis, the supermassive magnetized core model of Kundt (1978), and the model of Stoner and Ptak (1984) in which the supermassive stars maintain a kind of long-term quasi-stability, but accretion is balanced by mass loss and spherical bursts rather than in jets are considered. It is argued that the hypothesis that the supermassive blackholes are the central engines for AGN is based on theoretical principles; however, AGN emission line profiles and variability suggest a spherical geometry for the observed components of these engines. Also the supermassive black hole models do not account for all the AGN observations.

  5. ObsPy: A Python toolbox for seismology - Current state, applications, and ecosystem around it

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    ObsPy (http://www.obspy.org) is a community-driven, open-source project offering a bridge for seismology into the scientific Python ecosystem. It provides read and write support for essentially all commonly used waveform, station, and event metadata formats with a unified interface, a comprehensive signal processing toolbox tuned to the needs of seismologists, integrated access to all large data centers, web services and databases, and convenient wrappers to third party codes like libmseed and evalresp. Python, in contrast to many other languages and tools, 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 has to be translated to stable and production ready environments. It furthermore offers many freely available high quality scientific modules covering most needs in developing scientific software.ObsPy has been in constant development for more than 5 years and nowadays enjoys a large rate of adoption in the 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.This contribution will give a short introduction and overview of ObsPy and highlight a number of us cases and software built around it. We will furthermore discuss the issue of sustainability of scientific software.

  6. ObsPy: A Python toolbox for seismology - Current state, applications, and ecosystem around it

    NASA Astrophysics Data System (ADS)

    Lecocq, Thomas; Megies, Tobias; Krischer, Lion; Sales de Andrade, Elliott; Barsch, Robert; Beyreuther, Moritz

    2016-04-01

    ObsPy (http://www.obspy.org) is a community-driven, open-source project offering a bridge for seismology into the scientific Python ecosystem. It provides * read and write support for essentially all commonly used waveform, station, and event metadata formats with a unified interface, * a comprehensive signal processing toolbox tuned to the needs of seismologists, * integrated access to all large data centers, web services and databases, and * convenient wrappers to third party codes like libmseed and evalresp. Python, in contrast to many other languages and tools, 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 has to be translated to stable and production ready environments. It furthermore offers many freely available high quality scientific modules covering most needs in developing scientific software. ObsPy has been in constant development for more than 5 years and nowadays enjoys a large rate of adoption in the 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. This contribution will give a short introduction and overview of ObsPy and highlight a number of use cases and software built around it. We will furthermore discuss the issue of sustainability of scientific software.

  7. The QUEST Project: Research and Training in Computational Seismology

    NASA Astrophysics Data System (ADS)

    Igel, H.

    2012-04-01

    The Marie-Curie Initial Training Network QUEST joins scientists from 15 European partner institutions in the fields of exploration seismics, seismology, applied mathematics, high-performance computing, earthquake physics, physical inverse problems, geodynamics, from Departments of Mathematics, Physics, Earth and Computational Sciences, Oceanography and Exploration Geophysics. The main goal of QUEST is research and training in the development of strategies for seismic imaging using the increasing power of 3-D simulation technology. Existing methodologies are currently subject to a revolutionary change: While so far the observed information was severely reduced and approximate methods (e.g., ray theory) were used to determine Earth's structure, the massive increase in available computational resources allows us now to make use of the complete information contained in the observations. The QUEST objective is to integrate the various elements (wave propagation, high-performance computing, inverse problems) exploiting the synergies of the network expertise and develop the next generation of imaging tools for use on all spatial scales. We will discuss the training concepts of QUEST, the interfaces with other European projects like EPOS and VERCE. We will also describe the www-facilities QUEST offers concerning access to open-source software (e.g., ObsPy, simulation codes, analyitcal solutions) and interactive benchmarking facilities for wave propagation tools.

  8. Array seismological investigation of the South Atlantic 'Superplume'

    NASA Astrophysics Data System (ADS)

    Hempel, Stefanie; Gassmöller, Rene; Thomas, Christine

    2015-04-01

    We apply the axisymmetric, spherical Earth spectral elements code AxiSEM to model seismic compressional waves which sample complex `superplume' structures in the lower mantle. High-resolution array seismological stacking techniques are evaluated regarding their capability to resolve large-scale high-density low-velocity bodies including interior structure such as inner upwellings, high density lenses, ultra-low velocity zones (ULVZs), neighboring remnant slabs and adjacent small-scale uprisings. Synthetic seismograms are also computed and processed for models of the Earth resulting from geodynamic modelling of the South Atlantic mantle including plate reconstruction. We discuss the interference and suppression of the resulting seismic signals and implications for a seismic data study in terms of visibility of the South Atlantic `superplume' structure. This knowledge is used to process, invert and interpret our data set of seismic sources from the Andes and the South Sandwich Islands detected at seismic arrays spanning from Ethiopia over Cameroon to South Africa mapping the South Atlantic `superplume' structure including its interior structure. In order too present the model of the South Atlantic `superplume' structure that best fits the seismic data set, we iteratively compute synthetic seismograms while adjusting the model according to the dependencies found in the parameter study.

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

    NASA Astrophysics Data System (ADS)

    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

  10. Advanced light source. Activity report 1995

    SciTech Connect

    1996-07-01

    The ALS Activity Report is designed to share the breadth, variety, and interest of the scientific program and ongoing R&D efforts in a form that is accessible to a broad audience. Recent research results are presented in six sections, each representing an important theme in ALS science. These results are designed to demonstrate the capabilities of the ALS, rather than to give a comprehensive review of 1995 experiments. Although the scientific program and facilities report are separate sections, in practice the achievements and accomplishments of users and ALS staff are interdependent. This user-staff collaboration is essential to help us direct our efforts toward meeting the needs of the user community, and to ensure the continued success of the ALS as a premier facility.

  11. National Synchrotron Light Source 2008 Activity Report

    SciTech Connect

    Nasta,K.

    2009-05-01

    Funded by the U.S. Department of Energy's Office of Basic Energy Sciences, the National Synchrotron Light Source (NSLS) is a national user facility that operates two electron storage rings: X-Ray (2.8 GeV, 300 mA) and Vacuum Ultraviolet (VUV) (800 mev, 1.0A). These two rings provide intense light spanning the electromagnetic spectrum -- from very long infrared rays to ultraviolet light and super-short x-rays -- to analyze very small or highly dilute samples. The properties of this light, and the specially designed experimental stations, called beamlines, allow scientists in many diverse disciplines of research to perform experiments not possible at their own laboratories. Each year, about 2,200 scientists from more than 400 universities and companies use the NSLS for research in such diverse fields as biology, physics, chemistry, geology, medicine, and environmental and materials sciences. For example, researchers have used the NSLS to examine the minute details of computer chips, decipher the structures of viruses, probe the density of bone, determine the chemical composition of moon rocks, and reveal countless other mysteries of science. The facility has 65 operating beamlines, with 51 beamlines on the X-Ray Ring and 14 beamlines on the VUV-Infrared Ring. It runs seven days a week, 24 hours a day throughout the year, except during periods of maintenance and studies. Researchers are not charged for beam time, provided that the research results are published in open literature. Proprietary research is conducted on a full-cost-recovery basis. With close to 1,000 publications per year, the NSLS is one of the most prolific scientific facilities in the world. Among the many accolades given to its users and staff, the NSLS has won nine R&D 100 Awards for innovations ranging from a closed orbit feedback system to the first device able to focus a large spread of high-energy x-rays. In addition, a visiting NSLS researcher shared the 2003 Nobel Prize in Chemistry for work

  12. Capacity Building for Sustainable Seismological Networks in the Americas: A Pan-American Advanced Studies Institute on New Frontiers in Seismological Research

    NASA Astrophysics Data System (ADS)

    Cabello, O. A.; Meltzer, A.; Sandvol, E. A.; Yepes, H.; Ruiz, M. C.; Barrientos, S. E.; Willemann, R. J.

    2011-12-01

    During July 2011, a Pan-American Advanced Studies Institute, "New Frontiers in Seismological Research: Sustainable Networks, Earthquake Source Parameters, and Earth Structure" was conducted in Quito Ecuador with participants from the US, Central, and South America, and the Caribbean at early stages in their scientific careers. This advanced studies institute was imparted by fifteen volunteer senior faculty and investigators from the U.S. and the Americas. The curriculum addressed the importance of developing and maintaining modern seismological observatories, reviewed the principles of sustainable network operations, and explored recent advances in the analysis of seismological data in support of basic research, education, and hazard mitigation. An additional goal was to develop future international research collaborations. The Institute engaged graduate students, post-doctoral students, and new faculty from across the Americas in an interactive collaborative learning environment including modules on double-difference earthquake location and tomography, regional centroid-moment tensors, and event-based and ambient noise surface wave dispersion and tomography. Under the faculty guidance, participants started promising research projects about surface wave tomography in southeastern Brazil, near the Chilean triple junction, in central Chilean Andes, at the Peru-Chile border, within Peru, at a volcano in Ecuador, in the Caribbean Sea region, and near the Mendocino triple junction. Other participants started projects about moment tensors of earthquakes in or near Brazil, Chile and Argentina, Costa Rica, Ecuador, Puerto Rico, western Mexico, and northern Mexico. In order to track the progress of the participants and measure the overall effectiveness of the Institute a reunion is planned where the PASI alumni will present the result of their research that was initiated in Quito

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

    NASA Astrophysics Data System (ADS)

    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

  14. Seismological identification of the 1998 May 28 Pakistan nuclear test

    NASA Astrophysics Data System (ADS)

    Bowers, D.; Douglas, A.; Selby, N. D.; Marshall, P. D.; Porter, D.; Wallis, N. J.

    2002-07-01

    On 1998 May 28 Pakistan announced that it had conducted an underground nuclear test. Here we assess whether seismological data, recorded by the International Monitoring System (IMS) being set up to help verify the Comprehensive Test Ban Treaty (CTBT), can be used to identify the Pakistani test as a possible underground explosion. The prototype International Data Centre (pIDC) automatically determined the network-averaged body wave and surface wave magnitudes to be 4.9 and 3.6, respectively. One of the most reliable methods of identifying possible underground explosions is the mb : Ms criterion. However, mb : Ms is calibrated using conventional magnitudes from historical earthquakes and explosions. We calculate , in the conventional way, using P waves from the Pakistani test recorded by a simulated standard short-period seismograph and read by an experienced analyst. We also analyse the three components of the surface waves from the Pakistani test to confirm that these are correctly associated, and calculate . On mb : Ms the Pakistani test falls between the historical Eurasian underground explosion and earthquake populations. Thus, while the source may arouse suspicion on mb : Ms, its signature is typical of both explosions and deep-lithospheric Eurasian earthquakes. The vast majority of the seismic P signals from the Pakistani test, recorded at long range, are complex. However, simple P seismograms are recorded by at least three of the IMS stations. Analysis, using the relative amplitude method, of three of the simple P seismograms suggests that the source is shallow (less than 5 km). We conclude that the combination of the mb : Ms signature and shallow depth are sufficient to classify the Pakistani test as a possible explosion. Under the CTBT an on-site inspection would be required to determine whether the explosion was nuclear.

  15. Phase 1 immobilized low-activity waste operational source term

    SciTech Connect

    Burbank, D.A.

    1998-03-06

    This report presents an engineering analysis of the Phase 1 privatization feeds to establish an operational source term for storage and disposal of immobilized low-activity waste packages at the Hanford Site. The source term information is needed to establish a preliminary estimate of the numbers of remote-handled and contact-handled waste packages. A discussion of the uncertainties and their impact on the source term and waste package distribution is also presented. It should be noted that this study is concerned with operational impacts only. Source terms used for accident scenarios would differ due to alpha and beta radiation which were not significant in this study.

  16. VERCE - CPU-intensive Applications in Seismology

    NASA Astrophysics Data System (ADS)

    Simon, Marek; Leong, Siew Hoon; Zad, Kasra Hosseini; Krischer, Lion; Carpene, Michele; Ferini, Graziella; Trani, Luca; Spinuso, Alessandro; Magnoni, Federika; Casarotti, Emanuele; Gemünd, André; Weissenbach, David; Klampanos, Iraklis; Igel, Heiner

    2013-04-01

    Recently, advances in computational seismology have culminated in the development of a range of scientific codes enabling the calculation of highly accurate 3D wave and rupture propagation in complex 3D media at unprecedented scales and level of detail. Fortunately, the computational hardware has grown at rates at least as vigorous, to match up to the heavy requirements in CPU and memory imposed by realistic applications. However, as algorithmic and hardware complexity increases, making them work efficiently has become difficult: legacy codes need to be adapted and maintained by the community to meet the requirements of the new computational environments and the handling of large volumes of expensively generated data has become a challenge in itself. Within the VERCE (www.verce.eu) project, several specific use cases have been developed, exemplifying the challenges ahead. Seismic 3D-forward modelling of a large number of recorded earthquakes on a continental scale represents a model use case involving HPC. The simulation will be carried out on an HPC machine (SuperMUC, PLX), the resulting data submitted to a publicly accessible community Data-Center (ORFEUS) with the possibility to interactively mine and process the data using Grid infrastructure (Fraunhofer-SCAI, IPGP). As this basic workflow will need to be repeated for each solver, model, frequency range or processing option over and over again, the elements need to be connected within a workflow environment, allowing easy customization, job monitoring and visualisation of results. In collaboration with our VERCE partners, it was possible to define a basic core architecture for the VERCE platform for the proposed use case. Currently established components include JSAGA for job submission to GRAM, gLite Cream, gLite WMS as well as UNICORE6 instances, GridFTP for file transfer, using VOMS enabled certificate-based authentification. Additionally, a few suggested community applications (Seissol, Specfem3D Sesame

  17. Bringing Seismological Research into the School Setting

    NASA Astrophysics Data System (ADS)

    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

  18. A Green's function exchange platform for seismological research and education: applications and examples

    NASA Astrophysics Data System (ADS)

    Dahm, T.; Heimann, S.; Kriegerowski, M.; Cesca, S.; Wang, R.

    2015-12-01

    The study of seismic sources from measured waveforms requires synthetic elementary seismograms (Green's functions, GFs) calculated for specific earth models and source receiver geometries. Since the calculation of GFs is computationally expensive and requires careful parameter testing and quality control, pre-calculated GF databases, which can be re-used for different types of applications, can be of advantage. We developed a GF database web platform for the seismological community, where a researcher can share Green's function stores and retrieve synthetic seismograms on the fly for various point and extended earthquake source models for many different earth models at local, regional and global scale. This web service is part of a rich new toolset for the creation and handling of Green's functions and synthetic seismograms. It can be used off-line or in client mode. We demonstrate core features of the GF platform with different applications on global, regional and local scales. These include the automatic inversion of kinematic source parameters from teleseismic body waves, the improved depth estimate of shallow induced earthquakes from regional seismological arrays, or the relative moment tensor inversion of volcanic earthquakes.

  19. A Green's function database platform for seismological research and education: applications and examples

    NASA Astrophysics Data System (ADS)

    Heimann, Sebastian; Kriegerowski, Marius; Dahm, Torsten; Simone, Cesca; Wang, Rongjiang

    2016-04-01

    The study of seismic sources from measured waveforms requires synthetic elementary seismograms (Green's functions, GF) calculated for specific earth models and source receiver geometries. Since the calculation of GFs is computationally expensive and requires careful parameter testing and quality control, pre-calculated GF databases, which can be re-used for different types of applications, can be of advantage. We developed a GF database web platform for the seismological community (http://kinherd.org/), where a researcher can share Green's function stores and retrieve synthetic seismograms on the fly for various point and extended earthquake source models for many different earth models at local, regional and global scale. This web service is part of a rich new toolset for the creation and handling of Green's functions and synthetic seismograms (http://emolch.github.com/pyrocko/gf). It can be used off-line or in client mode. We demonstrate core features of the GF platform with different applications on global, regional and local scales. These include the automatic inversion of kinematic source parameter from teleseismic body waves, the improved depth estimate of shallow induced earthquakes from regional seismological arrays, or the relative moment tensor inversion of local earthquakes from volcanic induced seismicity.

  20. New science education initiative brings seismology into the classroom

    NASA Astrophysics Data System (ADS)

    Hamburger, Michael W.; Pavlis, Gary L.; Phinney, Robert A.; Steinberg, Daniel; Owens, Thomas J.; Hall-Wallace, Michelle

    Prince Galitsin's invention of the electromagnetic seismograph in 1914 revolutionized the young science of seismology. Now, the venerable research instrument is proving to have an equally powerful impact—in the arena of public education. Over the past 5 years, a number of initiatives have extended the boundaries of seismology research outside the ivory towers of research institutions and into America's schools, museums, and teaching colleges. These initiatives are built on the premise that educational seismology offers a special opportunity for capturing students' innate curiosity for natural phenomena in the world around them, and that this curiosity can be used to teach a wealth of fundamental principles of physics and Earth science. These school-based seismograph stations, now numbering in the hundreds, are demonstrating a growing potential to contribute both to science education and scientific research.

  1. Lifecycle of Seismological Data at IAG-USP

    NASA Astrophysics Data System (ADS)

    Pirchiner, M.; Assumpção, M. S.

    2012-04-01

    Historically the Brazilian Seismology never had a strategic vision solidified about how their data should be acquired, evaluated, stored and made available. The emergence of BRASIS (Integrated Seismological Network of Brazil) besides significantly increase the amount of acquired data also increases the number of analyses and possible uses of such data. At this point became clear the chance to implement an adequate management plan to cover this shortcoming. The 'integrated' nature of this network (made jointly by autonomous research groups) makes it even more critical aspects like authorship, authority, data access policies, among others. The purpose of this work is to present and criticize the efforts of IAG-USP Seismology Group in order to design and apply a data management plan that addresses data lifecycle as it has been discussed by the international community.

  2. A seismologically consistent compositional model of Earth's core.

    PubMed

    Badro, James; Côté, Alexander S; Brodholt, John P

    2014-05-27

    Earth's core is less dense than iron, and therefore it must contain "light elements," such as S, Si, O, or C. We use ab initio molecular dynamics to calculate the density and bulk sound velocity in liquid metal alloys at the pressure and temperature conditions of Earth's outer core. We compare the velocity and density for any composition in the (Fe-Ni, C, O, Si, S) system to radial seismological models and find a range of compositional models that fit the seismological data. We find no oxygen-free composition that fits the seismological data, and therefore our results indicate that oxygen is always required in the outer core. An oxygen-rich core is a strong indication of high-pressure and high-temperature conditions of core differentiation in a deep magma ocean with an FeO concentration (oxygen fugacity) higher than that of the present-day mantle. PMID:24821817

  3. A look at dynamic time warping in seismology

    NASA Astrophysics Data System (ADS)

    Mikesell, T. D.; Malcolm, A. E.; Mordret, A.; Bozdag, E.

    2015-12-01

    Dynamic time warping (DTW) is a method used to compare two time series. The idea is to search for a warping function that minimizes the misfit between the two time series. In seismology we can use DTW to measure arrival time differences in seismic traces or spatial differences in seismic images. Here we give an overview of the method and applications in seismology. We focus on a coda wave interferometry example and a waveform inversion example. We will cover the advantages of dynamic time warping; for example, DTW has been shown to outperform windowed-cross correlation when the signal-to-noise ratio is low. Finally, we will highlight new directions in which this method may find more application in seismology.

  4. A seismological perspective of the shallow magma and hydrothermal systems under Kilauea Caldera

    NASA Astrophysics Data System (ADS)

    Chouet, B. A.; Dawson, P. B.

    2011-12-01

    The past 20 years have seen great strides in our understanding of Kilauea Volcano, in large part due to technological developments and improvements in seismological instrumentation, which now allow the surface effects of subterranean volcanic processes to be imaged in unprecedented detail. High-resolution tomography provided an image of 3D velocity anomalies down to a scale of a few hundred meters, providing indirect evidence for the presence of reservoirs under the summit region of Kilauea. A sharper image of a shallow hydrothermal reservoir under Kilauea Caldera was obtained from frequency-slowness analyses of long-period (LP) seismicity recorded on three small-aperture seismic antennas deployed in the summit caldera. Located within the top 500 m below the caldera floor and extending ~0.6 km and ~1 km in the east-west and north-south directions, this hydrothermal reservoir broadly overlaps the east wall of the Halemaumau pit crater. Further evidence of hydrothermal processes within this zone was obtained from a study of a well-recorded LP event, indicating a source mechanism consistent with the resonance of a horizontal steam-filled crack at a depth of ~150 m near the eastern rim of Halemaumau. Recurring very-long-period (VLP) signals originating in the repeated activation of a compact source region near sea level immediately beneath this hydrothermal reservoir have allowed a gradually emerging view of the shallowest segment of the magma transport pathway under the caldera. Further elaboration of our image of the magma pathway structure, made possible through detailed modeling of VLP signals accompanying degassing activity at a new vent formed in Halemaumau in March 2008, points to a dominant dike segment in the form of a nearly vertical east-trending dike. The inferred dike features a ~20° clockwise rotation in strike under the east edge of Halemaumau, where it intersects a sub-vertical north-striking dike. The triple junction made by the intersection of the

  5. EMITTING ELECTRONS AND SOURCE ACTIVITY IN MARKARIAN 501

    SciTech Connect

    Mankuzhiyil, Nijil; Ansoldi, Stefano; Persic, Massimo; Rivers, Elizabeth; Rothschild, Richard; Tavecchio, Fabrizio

    2012-07-10

    We study the variation of the broadband spectral energy distribution (SED) of the BL Lac object Mrk 501 as a function of source activity, from quiescent to flaring. Through {chi}{sup 2}-minimization we model eight simultaneous SED data sets with a one-zone synchrotron self-Compton (SSC) model, and examine how model parameters vary with source activity. The emerging variability pattern of Mrk 501 is complex, with the Compton component arising from {gamma}-e scatterings that sometimes are (mostly) Thomson and sometimes (mostly) extreme Klein-Nishina. This can be seen from the variation of the Compton to synchrotron peak distance according to source state. The underlying electron spectra are faint/soft in quiescent states and bright/hard in flaring states. A comparison with Mrk 421 suggests that the typical values of the SSC parameters are different in the two sources: however, in both jets the energy density is particle-dominated in all states.

  6. The Swiss Seismological Service in Greenland: Network Building and Research Initiatives

    NASA Astrophysics Data System (ADS)

    Husen, S.; Clinton, J. F.; Olivieri, M.; Giardini, D.

    2010-12-01

    In recent years the Swiss Seismological Service (SED) at the ETH Zürich has begun active work in NW Greenland. As part of the GreenLand Ice Sheet monitoring Network (GLISN), a new international, broadband seismic capability for Greenland, the SED has installed 3 observation quality stations, recording in realtime, with data freely open to the community. Each site is located at a village - two are within 60km of productive calving glacier fronts (Rink and Jakobshavn); the other station is 30km from inland ice calving directly into the ocean. This paper presents the stations and discusses the data quality. The capability of broadband seismic sensors at local distances to record a wide spectrum of ground motion induced by large calving events is becoming clear. Associated with a major calving event, we observe energy at 1. high frequencies (1-5Hz) due to ice fracture; 2. at mid periods (40-60s - visible at teleseismic distances) likely due to large, rapid displacement of the calved ice across the fjord floor; and 3. at longer periods (100-1000s) measuring fjord seiche generated by the calved iceberg. We are developing an automated detector for events using the GLISN dataset, with focus on the Swiss stations. Additionally, the SED, with the ETH Glaciology unit, intend to operate a broadband / short period seismic network on the ice near SwissCamp in summer 2011. The goal is to improve understanding of how sub-glacial water affects glacial bed coupling. We aim to generate an icequake catalogue with characterized sources, and to model transient changes in ice structure than may be indicative of water flow. We present a summary of the proposed work and installation plans.

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

    NASA Astrophysics Data System (ADS)

    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

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

    USGS Publications Warehouse

    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

  9. Active radiation hardening technology for fiber-optic source

    NASA Astrophysics Data System (ADS)

    Yang, Yuanhong; Suo, Xinxin; Yang, Mingwei

    2013-09-01

    We demonstrated an active radiation hardening technology for fiber optic source developed for high performance fiber optic gyroscope. The radiation characteristic of erbium-doped fiber was studied experimentally. The radiation induced attenuation (RIA) at 980nm pump light was identified to be the main reason for the degradation and there was photo-bleaching effect in EDF too. A variable parameters control technology was proposed and taken to keep the 980nm and 1550nm light energy stable and high stability and radiation-resistance fiber source with gauss profile spectrum was realized .The source can stand against more than 50 krad (Si) total radiation dose.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  11. Sub-crustal earthquakes beneath the Gulf of Cadiz - First results from seismological observations with the NEAREST OBS network

    NASA Astrophysics Data System (ADS)

    Geissler, W. H.; Matias, L. M.; Monna, S.; Stich, D.; Iben Brahim, A.; Mancilla, F.; Zitellini, N.; Nearest Working Group

    2009-04-01

    The geophysical and geological investigations conducted so far in the Gulf of Cadiz allow us today to have an idea of the largest active faults that can generate destructive earthquakes and tsunamis comparable to the Nov 1st, 1755 Lisbon event. However, their kinematics and seismic activity are poorly known because the seismic networks based on land do not allow a precise hypocenter location and estimation of focal mechanisms for the smaller events. Therefore the EC project NEAREST (Integrated observation from NEAR shore sourcES of Tsunamis: towards an early warning system) was initiated (GOCE, contract n. 037110). One of the main objectives of the project is the characterisation of the tsunamigenic sources in the Gulf of Cadiz through seismological monitoring of natural seismicity by means of 24 BB seismometers deployed for 11 months in addition to the GEOSTAR multi-parameter deep-sea observatory. Together with the dense onshore seismic networks the temporary OBS network will allow the location and characterization of small seismic events more precisely than it can be done with onshore stations only. Spectrograms are used to identify previously unknown earthquakes. One of the major questions is the maximum depth of seismic activity beneath the Gulf of Cadiz. In the recording period from September 2007 to August 2008 about 300 events were located within the OBS network using the Portuguese onshore seismic stations. Magnitudes range from 1 to 4.7 (ML from Institute of Meteorology Lisbon, Portugal). Using the OBS network many events could be detected which are not located by the onshore stations. First results show that the events occur to approximately 50 km depth, often deeper than the locations by land stations, and confirming the results available from regional and teleseismic waveform modelling. Focal mechanisms show strike-slip and thrust-slip events.

  12. Long-period (12sec) Volcanic Tremor Observed at Usu 2000 Eruption: Seismological Detection of a Deep Magma Plumbing system

    NASA Astrophysics Data System (ADS)

    KAWAKATSU, H.; YAMAMOTO, M.

    2001-12-01

    Mt. Usu is a dacitic stratovolcano located in southwestern Hokkaido, Japan, and has erupted repeatedly (in 1910, 1943-45, and 1977-78). In the end of March 2000, after twenty some years of quiescence, Usu volcano began its activity with an intensive earthquake swarm. After several days of the earthquake swarm, on March 31, 2000, the eruption began at the northwest foot of the volcano. We have installed five broadband seismometers around the volcano, and detected long period (12 sec) tremors (hereafter called LPTs) which are continually emitted from the volcano. Although these LPTs are continually observed at an interval of a few minutes, there exist no corresponding surface activities such as eruptions. The source of these LPTs are located relatively deep at a depth of 5 km, and their amplitude variation well correlates with the uplift rate of the eruption area. We thus attribute these LPTs to the flow induced vibration of a magma chamber and its outlet located around the source region of the LPTs. The estimated moment tensor for LPTs shows a reversed polarity for the isotropic and CLVD components. This is consistent with a combination of a deflating spherical source and an inflating crack which opens northwestern direction toward the eruption site. The volumetric magma flow rate may be estimated from the observed RMS amplitude of LPT through a seismic moment rate, and turns out to be around 3*E5 m3 per day. Geodetic observations report the volume change of the order of 107 m3 within the first few days. It appears that the volume flow rate estimated from LPTs is about one order of magnitude smaller than that of the actual flow rate. This may be reasonable if we consider that through seismic waves we are observing a fluctuating part of the magma flow. This may be the first seismological detection of dynamics of a main magma plumbing system beneath volcanos directly related to eruption activities.

  13. Macroscopic Fault Structure of the 1911 Mw8.1 Chon Kemin Earthquake (Tien Shan, Kyrgyzstan) from Combined Seismic Imaging, Palaeo-Seismological Investigations and Historial Seismicity

    NASA Astrophysics Data System (ADS)

    Haberland, C. A.; Sonnemann, T.; Landgraf, A.; Ryberg, T.; Kulikova, G.; Krueger, F.; Dzhumabaeva, A.; Abdrakhmatov, K.; Abdybachaev, U.; Orunbaev, S.; Rosenwinkel, S.; Sharshebaev, A.

    2014-12-01

    Earthquakes in low-strain regions and their driving forces are still sparsely studied and understood, and constitute serious first-order research questions. Data acquisition concerning paleo-earthquakes, related hazards, and tectonic activity beyond historical records plays an important role. Such information can be obtained with tools from tectonic geomorphology, geophysics, historic seismicity, and paleo-seismology that should span a variety of time and length scales. The Chon-Kemin Valley in the northern Tien Shan (Kyrgyzstan) is a small, intermontane basin of unknown origin framed by a network of active faults. In the year 1911, the Chon-Kemin earthquake (Mw=8.1) activated fault structures of about 200 km length which also ruptured the surface along the Chon-Kemin Valley and caused numerous landslides and rock avalanches of up to several tens of millions of cubic meters in volume. The Chon-Kemin earthquake was one of a series of strong seismic events that affected the northern Tien Shan between 1885 and 1938. A seismic survey across the Chon-Kemin Valley was conducted to investigate the subsurface velocity structure of the valley and its surrounding faults. Tomographic inversion techniques were applied to first-arrival traveltimes of refracted P waves, and the seismic data were screened for reflection signatures. Additionally, the region was analyzed through paleo-seismological trenching. Tomographic and reflection images identified a shallow basin structure bounded by a set of thrust faults in the south only which - in part - correlate with the surface trace of the rupture. The deformation seems to be distributed in time and space across several sub-parallel fault strands. Synthesis of historical (analog) recordings of this earthquake provide new insights into the source mechanisms and processes.

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

    NASA Astrophysics Data System (ADS)

    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

  15. Surface Plasma Source Electrode Activation by Surface Impurities

    SciTech Connect

    Dudnikov, Vadim; Johnson, Rolland P.; Han, B.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Stockli, Martin P.; Welton, R. F.

    2011-09-26

    In experiments with RF saddle antenna surface plasma sources (SPS), the efficiency of H{sup -} ion generation was increased by up to a factor of 5 by plasma electrode 'activation', without supplying additional Cs, by heating the collar to high temperature for several hours using hot air flow and plasma discharge. Without cracking or heating the cesium ampoule, but likely with Cs recovery from impurities, the achieved energy efficiency was comparable to that of conventionally cesiated SNS RF sources with an external or internal Cs supply. In the experiments, optimum cesiation was produced (without additional Cs) by the collection and trapping of traces of remnant cesium compounds from SPS surfaces. Such activation by accumulation of impurities on electrode surfaces can be a reason for H{sup -} emission enhancement in other so-called 'volume' negative ion sources.

  16. Experimental study on anelasticty of polycrystalline material for seismological application

    NASA Astrophysics Data System (ADS)

    Takei, Y.; Karasawa, F.

    2012-12-01

    Due to the recent progress in seismology, we can obtain highly-resolved seismic velocity structures in the upper mantle. In order to interpret the velocity structures in terms of temperature heterogeneity, chemical heterogeneity, and fluid/melt distribution, it is important to assess the quantitative effects of temperature, chemical composition, and fluid/melt on Vp and Vs. Although these effects at the ultrasonic frequencies (anharmonic effect, poroelastic effect) have been measured and assessed quantitatively, these effects at the seismic frequencies are subject to large uncertainty due to the uncertainty in rock anelasticity, which additionally causes modulus relaxation at lower frequencies (anelastic effect). Previous studies have shown that anelasticity of polycrystalline materials follows the similarity rule in which frequency normalized to the Maxwell frequency, f/fM, can be used as a master variable (Morris & Jackson, 2009a; McCarthy et al, 2012). The general applicability of this Maxwell frequency scaling shows that the anelastic relaxation in those experiments is caused by diffusionally accommodated grain boundary sliding (GBS) (Gribb & Cooper, 1998; McCarthy et al, 2012). However, normalized frequency of the existing experimental data is usually considerably lower than the seismic frequencies normalized to the Maxwell frequency of the upper mantle (f/fM=106-1010). Therefore, in order to clarify the mechanism and scaling law applicable to the seismic waves, we have to measure anelasticity at higher normalized frequencies. Theoretical models (e.g., Raj, 1975; Morris & Jackson, 2009b) predict that at higher normalized frequencies, dominant GBS mechanism changes from diffusionally accommodated GBS to elastically accommodated GBS. However, the transition frequency and total relaxation strength associated with the elastically accommodated GBS, which are important in the application to seismology, have so far been difficult to constrain theoretically

  17. Advanced Light Source Activity Report 1997/1998

    SciTech Connect

    Greiner, Annette

    1999-03-01

    This Lawrence Berkeley National Laboratory, Advanced Light Source (ALS) activity report for 1997/98 discusses the following topics: Introduction and Overview; Science Highlights; Facility Report; Special Events; ALS Advisory Panels 1997/98; ALS Staff 1997/98 and Facts and Figures for the year.

  18. Volcano Seismology GEOS 671, A Graduate Course at the University of Alaska Fairbanks

    NASA Astrophysics Data System (ADS)

    McNutt, S. R.

    2002-05-01

    Volcano seismology is a discipline that straddles seismology and volcanology. It consists of an abundance of specialized knowledge that is not taught in traditional seismology courses, and does not exist in any single book or textbook. Hence GEOS 671 was developed starting in 1995. The following topics are covered in the course: history and organization of the subject; instruments and networks; seismic velocities of volcanic materials; terminology and event classification; swarms, magnitudes, energy, b-values, p-values; high frequency (VT, A-type) earthquakes; low frequency (LP, B-type, VLP) earthquakes; volcanic tremor; volcanic explosions (C-type); attenuation and noise at volcanoes; large earthquakes near volcanoes; cycles of volcanic activity; forecasting of eruptions and assessment of eruptions in progress; magma chambers, S-wave screening, and tomography; selected topics, such as probability, chaos, lightning, and modelling. Case studies help illuminate the basic principles by providing benchmarks and specific examples of important trends, patterns, or dominant processes. Case studies include: Arenal 1968-2002; Redoubt 1989-90; Spurr 1992; Usu 1977; Mount St. Helens 1980; Kilauea 1983; Izu-Oshima 1986; Galeras 1988-1993; Long Valley 1980-1989; Pinatubo 1991; and Rabaul 1981-1994. The students each present two case studies during the semester. GEOS 671 has been taught 4 times (every other year) with 4-8 students each time. At least one student term paper from each class has been expanded into a published work. To keep up with new research, about 15 percent new material is added each time the course is taught. Finally, Alaska is home to 41 historically active volcanoes (80 Holocene) of which 23 are monitored with seismic networks. Students have a strong chance to apply what they learn in the course during real eruptive crises.

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

    NASA Astrophysics Data System (ADS)

    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

  20. Public health genetic counselors: activities, skills, and sources of learning.

    PubMed

    McWalter, Kirsty M; Sdano, Mallory R; Dave, Gaurav; Powell, Karen P; Callanan, Nancy

    2015-06-01

    Specialization within genetic counseling is apparent, with 29 primary specialties listed in the National Society of Genetic Counselors' 2012 Professional Status Survey (PSS). PSS results show a steady proportion of genetic counselors primarily involved in public health, yet do not identify all those performing public health activities. Little is known about the skills needed to perform activities outside of "traditional" genetic counselor roles and the expertise needed to execute those skills. This study aimed to identify genetic counselors engaging in public health activities, the skills used, and the most influential sources of learning for those skills. Participants (N = 155) reported involvement in several public health categories: (a) Education of Public and/or Health Care Providers (n = 80, 52 %), (b) Population-Based Screening Programs (n = 70, 45 %), (c) Lobbying/Public Policy (n = 62, 40 %), (d) Public Health Related Research (n = 47, 30 %), and (e) State Chronic Disease Programs (n = 12, 8 %). Regardless of category, "on the job" was the most common primary source of learning. Genetic counseling training program was the most common secondary source of learning. Results indicate that the number of genetic counselors performing public health activities is likely higher than PSS reports, and that those who may not consider themselves "public health genetic counselors" do participate in public health activities. Genetic counselors learn a diverse skill set in their training programs; some skills are directly applicable to public health genetics, while other public health skills require additional training and/or knowledge. PMID:25475919

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  3. Surface Plasma Source Electrode Activation by Surface Impurities

    SciTech Connect

    Dudnikov, Vadim; Han, Baoxi; Johnson, Rolland P.; Murray Jr, S N; Pennisi, Terry R; Santana, Manuel; Stockli, Martin P; Welton, Robert F

    2011-01-01

    In experiments with RF saddle antenna surface plasma sources (SPS), the efficiency of H- ion generation was increased by up to a factor of 5 by long time plasma electrode activation, without adding Cs from Cs supply, by heating the collar to high temperature using hot air flow and plasma discharge. Without cracking or heating the cesium ampoule, but likely with Cs recovery from impurities, the achieved energy efficiency was comparable to that of conventionally cesiated SNS RF sources with an external or internal Cs supply. In the experiments, perfect cesiation was produced (without additional Cs supply) by the collection and trapping of traces of remnant cesium compounds from SPS surfaces.

  4. Amphibian Seismological Studies in the Ross Sea, Antarctica

    NASA Astrophysics Data System (ADS)

    Schmidt-Aursch, Mechita; Kuk Hong, Jong; Lee, Won Sang; Geissler, Wolfram; Yun, Sukyoung; Gohl, Karsten; Park, Yongcheol; Yoo, Hyun Jae

    2016-04-01

    The Antarctic Ross Sea is one of the key regions for polar research activities. Research stations from several countries located at the coast are the base for inland expeditions. Even in the austral summer, the Ross Sea is party covered with drifting ice fields; this requires an icebreaker for all marine explorations. Therefore, large geophysical surveys in the Ross Sea are difficult. But the area is of special interest for seismologists: The Terror Rift in the western Ross Sea is a prominent neotectonic structure of the West Antarctic Rift System (WARS). It is located near the coast in the Victoria Land Basin and extends parallel to the Transantarctic Mountains. The rifting processes and the accompanying active onshore volcanism lead to increased seismicity in the region. The annual waxing and waning of the sea-ice and the dynamics of the large Ross Ice Shelf and nearby glaciers generate additional seismic signals. Investigation on seismological activities associated with the WARS and the cryogenic signals simultaneously would give us an unprecedented opportunity to have a better understanding of the Evolution of the WARS (EWARS) and the rapid change in the cryospheric environment nearby. The Korea Polar Research Institute (KOPRI) and the Alfred-Wegener-Institut (AWI) have conducted a pilot study off the Korean Jang Bogo research station in the Terra Nova Bay by developing a collaborative research program (EWARS) since 2011 to explore seismicity and seismic noise in this region. Four broadband ocean-bottom seismometers (OBS) from the German DEPAS pool were deployed in January 2012 with the Korean research icebreaker RV Araon. Three instruments could successfully be recovered after 13 months, the fourth OBS was not accessible due to local sea-ice coverage. We have successfully completed a second recovery operation in January 2014. All stations recorded data of good quality, one station stopped after 8 months due to a recorder error. The OBS recovered in 2014

  5. Sources of the solar wind at solar activity maximum

    NASA Astrophysics Data System (ADS)

    Neugebauer, M.; Liewer, P. C.; Smith, E. J.; Skoug, R. M.; Zurbuchen, T. H.

    2002-12-01

    The photospheric sources of solar wind observed by the Ulysses and ACE spacecraft from 1998 to early 2001 are determined through a two-step mapping process. Solar wind speed measured at the spacecraft is used in a ballistic model to determine a foot point on a source surface at a solar distance of 2.5 solar radii. A potential-field source-surface model is then used to trace the field and flow from the source surface to the photosphere. Comparison of the polarity of the measured interplanetary field with the polarity of the photospheric source region shows good agreement for spacecraft latitudes equatorward of 60°. At higher southern latitudes, the mapping predicts that Ulysses should have observed only outward directed magnetic fields, whereas both polarities were observed. A detailed analysis is performed on four of the solar rotations for which the mapped and observed polarities were in generally good agreement. For those rotations, the solar wind mapped to both coronal holes and active regions. These findings for a period of high solar activity differ from the findings of a similar study of the solar wind in 1994-1995 when solar activity was very low. At solar minimum the fastest wind mapped to the interior of large polar coronal holes while slower wind mapped to the boundaries of those holes or to smaller low-latitude coronal holes. For the data examined in the present study, neither spacecraft detected wind from the small polar coronal holes when they existed and the speed was never as high as that observed by Ulysses at solar minimum. The principal difference between the solar wind from coronal holes and from active regions is that the O7+/O6+ ion ratio is lower for the coronal hole flow, but not as low as in the polar coronal hole flow at solar minimum. Furthermore, the active-region flows appear to be organized into several substreams unlike the more monolithic structure of flows from coronal holes. The boundaries between plasma flows from neighboring

  6. Seismology@School - Nearly 20 years for the first experiences in Europe

    NASA Astrophysics Data System (ADS)

    Berenguer, Jean Luc; Balestra, Julien; Courboulex, Françoise

    2016-04-01

    The original and innovative aspect of this programme stems from giving students the opportunity to install a seismometer in their school. The recorded signals, reflecting regional or global seismic activity, feed into an on-line database, a genuine seismic resource centre and a springboard for educational and scientific activities. In the footsteps of the U.S PEPP project, we have started this experiment in Europe in order to see how we can confront high school students with the current practice of scientific data acquisition, and how we can establish a specific educational structure tailored to the European system. The French network 'EduSismo' (numbering some hundred stations installed in metropolitan France, the overseas departments and territories and a few French high schools abroad) is the outgrowth of an experiment conducted some twenty years back. Since then, the programme implemented has gone beyond simply acquiring seismic signals, which could have been procured by research and monitoring centres. By appropriating a scientific measurement, the student becomes personally involved and masters complex concepts about geophysics and geosciences. The development of simple devices and the design of concrete experiments associated with an investigative approach make it possible to instil the students with a high-quality scientific culture and an education about risks. A lot of similar projects were run in Europe and more … data streaming, database on line, examples of models … are not the only link between schools. The European network stay alive with some events: 'EDUSEIS', 'NaRAS', 'O3E', 'NERA' European programs, teachers/researchers workshops, school challenges, projects between schools, social network … it was a great opportunity to share experiences with teachers and researchers through a huge worldwide network. During the twenty last years, 'Seismology@school' concept has developed initiatives to link more people, and has provided more tools to teach

  7. 20 year IRIS: impact on seismological research at home and abroad

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  12. Seismology of the Oso-Steelhead landslide

    NASA Astrophysics Data System (ADS)

    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.

  13. How real-time seismological data can be used at school

    NASA Astrophysics Data System (ADS)

    Emolo, Antonio; Bobbio, Antonella; Cantore, Luciana; Del Gaudio, Sergio; Elia, Luca; Festa, Gaetano; Lucca, Ernestina; Miranda, Nicola; Orefice, Antonella; Zollo, Aldo

    2013-04-01

    The feasibility and possible implementation of real time-earthquake risk reduction systems focused on the decrease of the building vulnerability and people exposure, are important issues of the EU projects REAKT (Strategies and tools for Real Time Earthquake RisK ReducTion) and NERA (Network of European research infrastructures for earthquake risk assessment and mitigation). Both projects aim at developing methodologies based on earthquake forecasting, early-warning and real-time vulnerability systems, to establish best practices for their use for risk mitigation actions. In this framework, it is important to apply real-time mitigation actions to different situations (trains, industries, hospitals, bridges, schools, and so on). For schools, advanced seismic stations are being installed in different European countries, to enable rapid and user-friendly analysis, data modeling and interpretation. All of these activities will be performed by teachers and students. In Italy three high-schools located in the Irpinia region (Southern Italy), and two in the Naples outskirts are involved in such projects. The schools host a strong-motion station which is integrated in the earthquake Early-Warning System (EWS) network deployed along the southern Apenninic chain. Data streams are analyzed in real-time by the software platform PRESToPlus, which provides both threshold based regional and on-site early-warning. The early-warning application for the schools could be defined as 'passive' because they will receive the alert from the PRESToPlus EWS. However, it will be also possible to monitor the ground-shaking really experienced at these sites, so to update the information flowing into the EEW system from the whole network. Educational activities involving both teachers and students are planned for the schools which participate in the early-warning projects. These activities are aimed at providing a basic knowledge about seismology in general, and on seismic early

  14. How real-time seismological data can be used at school

    NASA Astrophysics Data System (ADS)

    Cantore, L.; Emolo, A.; Festa, G.; Bobbio, A.; Zollo, A.

    2012-12-01

    The feasibility and possible implementation of real time-earthquake risk reduction systems focused on the decrease of the building vulnerability and people exposure, are important issues of the EU projects REAKT (Strategies and tools for Real Time Earthquake RisK ReducTion) and NERA (Network of European research infrastructures for earthquake risk assessment and mitigation). Both projects aim at developing methodologies based on earthquake forecasting, early-warning and real-time vulnerability systems, to establish best practices for their use for risk mitigation actions. In this framework, it is important to apply real-time mitigation actions to different situations (trains, industries, hospitals, bridges, schools, and so on). For schools, advanced seismic stations are being installed in different European countries, to enable rapid and user-friendly analysis, data modeling and interpretation. All of these activities will be performed by teachers and students. In Italy three high-schools located in the Irpinia region (Southern Italy), and two in the Naples outskirts are involved in such projects. The schools host a strong-motion station which is integrated in the earthquake Early-Warning System (EWS) network deployed along the southern Apenninic chain. Data streams are analyzed in real-time by the software platform PRESToPlus, which provides both threshold based regional and on-site early-warning. The early-warning application for the schools could be defined as 'passive' because they will receive the alert from the PRESToPlus EWS. However, it will be also possible to monitor the ground-shaking really experienced at these sites, so to update the information flowing into the EEW system from the whole network. Educational activities involving both teachers and students are planned for the schools which participate in the early-warning projects. These activities are aimed at providing a basic knowledge about seismology in general, and on seismic early

  15. Seismology program; California Division of Mines and Geology

    USGS Publications Warehouse

    Sherburne, R. W.

    1981-01-01

    The year 1980 marked the centennial of the California Division of Mines and Geology (CDMG) and a decade of the Division's involvement in seismology. Factors which contributed to the formation of a Seismology Group within CDMG included increased concerns for environmental and earthquake safety, interest in earthquake prediction, the 1971 San Fernando earthquake and the 1973 publication by CDMG of an urban geology master plan for California. Reasons to be concerned about California's earthquake problem are demonstrated by the accompanying table and the figures. Recent seismicity in California, the Southern California uplift reflecting changes in crustal strain, and other possible earthquake precursors have heightened concern among scientific and governmental groups about the possible occurrence of a major damaging earthquake )M>7) in California. 

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    community. It enables active researchers to invent and refine scalable methods for innovative statistical analysis of seismic waveforms in a wide range of application contexts. The VRE paves the way towards a flexible shared framework for seismic waveform inversion, lowering the barriers to uptake for the next generation of researchers. The VRE can be accessed through the science gateway that puts together computational and data-intensive research into the same framework, integrating multiple data sources and services. It provides a context for task-oriented and data-streaming workflows, and maps user actions to the full gamut of the federated platform resources and procurement policies, activating the necessary behind-the-scene automation and transformation. The platform manages and produces domain metadata, coupling them with the provenance information describing the relationships and the dependencies, which characterise the whole workflow process. This dynamic knowledge base, can be explored for validation purposes via a graphical interface and a web API. Moreover, it fosters the assisted selection and re-use of the data within each phase of the scientific analysis. These phases can be identified as Simulation, Data Access, Preprocessing, Misfit and data processing, and are presented to the users of the gateway as dedicated and interactive workspaces. By enabling researchers to share results and provenance information, VERCE steers open-science behaviour, allowing researchers to discover and build on prior work and thereby to progress faster. A key asset is the agile strategy that VERCE deployed in a multi-organisational context, engaging seismologists, data scientists, ICT researchers, HPC and data resource providers, system administrators into short-lived tasks each with a goal that is a seismology priority, and intimately coupling research thinking with technical innovation. This changes the focus from HPC production environments and community data services to user

  17. Sources of solar wind over the solar activity cycle.

    PubMed

    Poletto, Giannina

    2013-05-01

    Fast solar wind has been recognized, about 40 years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review. PMID:25685421

  18. Electrode activation in cesium-free negative ion sources

    SciTech Connect

    Dudnikov, Vadim; Johnson, Rolland P.

    2010-02-15

    Features of emission electrode activation leading to enhancement of negative ion emission in cesium-free discharges are discussed. In some ion sources with cesium-free discharges, the emission of negative ions has been increased significantly by emission electrode activation using strong heating of the negative biased electrode by discharge plasma. A simple explanation of this enhancement is that it is due to an accumulation on the emission surface of the plasma electrode of impurities with low ionization potential that decreases in surface work function and increases the secondary emission of negative ions similar to ''Cesiation.'' The negative biasing of emission surface is important for accumulation and trapping the impurities on the emission surface. To effectively control the activation process it is important to directly detect the evolution of the work function and the impurity concentration during electrode activation with enhancement of negative ion emission.

  19. A Global Network for Educational Seismology ready to be used by everyone

    NASA Astrophysics Data System (ADS)

    Courboulex, F.; Bérenguer, J.; Tocheport, A.; Esnault, Y.; Larroque, C.; Jouffrey, F.; Nolet, G.; Deschamps, A.; Sladen, A.; Balestra, J.

    2013-12-01

    The French ';Sismos à l'Ecole' (Seismology at School or SaE) network currently comprises 60 seismic stations installed in French high schools: 40 inside France and 20 around the world (including the ';La Perouse' school in San Francisco). At this moment the network is mainly composed of 3-component digital stations with a broad-band sensor. All data have open access through a website (www.edusismo.org). Seismograms are used by students, teachers and researchers. In addition to this worldwide permanent backbone we are developing a secondary network with a simpler low-cost station: a basic digitizer with a one-component sensor that can be fixed to the wall of a school. The data of these stations are also freely available in real time and permit the development of student projects on seismology and seismic risk in a larger number of schools. The SaE network currently involves about 100 secondary teachers, as well as 20 researchers motivated to give students practical experience on a broad range of topics involving several disciplines in secondary education (geology, physics, geography, technology ...). The network is a starting point for more advanced educational activities such as the processing and interpretation of real data, quality assessment, and use of databases. In addition it promotes the awareness of seismic risk. We invite all the teachers and researchers around the world who would like to do experimental seismology with their students to use the data and the tools on the website that are in both a French and an English version. For the past 2 years, SaE has also been expanding through the European NERA project, which aim is to share data and experience in educational seismology in Europe and abroad. We shall soon add a new component 'Adopt a Mermaid' - in which classes can follow the new floating seismometers developed at Geoazur (see session S008) and deployed in the Mediterranean and Indian Ocean, try to predict their trajectories and learn about the

  20. The role of instruments in the history of Geophysics: the case of Seismology

    NASA Astrophysics Data System (ADS)

    Ferrari, Graziano

    2015-04-01

    Science is the study that leads to discriminate knowledge of the material world based on observation, experiment and induction. Geophysics is the combination of the former concern about the explanation of every day phenomena in our enviroment, with the achievements of physics that were exploited within the laboratory, either by experiments or by theoreticians. Unlike other disciplines such as physics or chemistry, geophysics is a mosaic of disciplines also very different among each other. The main differences concern the object and method of study or the evolutionary path. Many cyclic phenomena of the Earth are long-term processes so that a long period of study is essential to a thorough understanding. Extreme natural events such as earthquakes, volcanic eruptions, floods, etc. significantly contribute to the natural hazards. So, in seismology, volcanology, hydrogeology, as in those disciplines who study significant changes in climate or in geomagnetism, long time series of data are very useful, along with the instruments that registered them and the scientific paradigms within which they were produced. These aspects, contributing to the history of geophysics, are extremely useful especially for the fallout on the mankind's life and activities.To be useful, as well as the recovery, the historical data must be "normalized" to the current use we want to do of them. This process makes an essential contribution to knowledge of the instruments that recorded this data: their principles of operation, their constants and their variability over time. Many of the disciplines involved in geophysics, as seismology, geomagnetism, etc. require observations both geographically distributed and synchronized. Geomagnetic and seismological recordings, together with astronomical and meteorological observations have been frequently done in the same observatories, in the past. Despite their relative cyclic nature, since earthquakes may not occur in the exact same way, thorough analysis

  1. The IRIS Federator: Accessing Seismological Data Across Data Centers

    NASA Astrophysics Data System (ADS)

    Trabant, C. M.; Van Fossen, M.; Ahern, T. K.; Weekly, R. T.

    2015-12-01

    In 2013 the International Federation of Digital Seismograph Networks (FDSN) approved a specification for web service interfaces for accessing seismological station metadata, time series and event parameters. Since then, a number of seismological data centers have implemented FDSN service interfaces, with more implementations in development. We have developed a new system called the IRIS Federator which leverages this standardization and provides the scientific community with a service for easy discovery and access of seismological data across FDSN data centers. These centers are located throughout the world and this work represents one model of a system for data collection across geographic and political boundaries.The main components of the IRIS Federator are a catalog of time series metadata holdings at each data center and a web service interface for searching the catalog. The service interface is designed to support client­-side federated data access, a model in which the client (software run by the user) queries the catalog and then collects the data from each identified center. By default the results are returned in a format suitable for direct submission to those web services, but could also be formatted in a simple text format for general data discovery purposes. The interface will remove any duplication of time series channels between data centers according to a set of business rules by default, however a user may request results with all duplicate time series entries included. We will demonstrate how client­-side federation is being incorporated into some of the DMC's data access tools. We anticipate further enhancement of the IRIS Federator to improve data discovery in various scenarios and to improve usefulness to communities beyond seismology.Data centers with FDSN web services: http://www.fdsn.org/webservices/The IRIS Federator query interface: http://service.iris.edu/irisws/fedcatalog/1/

  2. First steps of a Seismology at School project in Belgium

    NASA Astrophysics Data System (ADS)

    Lecocq, T.; Oconnor, C.; Camelbeeck, T.

    2012-12-01

    We present the first results of the seismology at school project that just started in January 2012 in Belgium in collaboration between the Royal Observatory of Belgium and the European School of Brussels #4. We present and compare recordings of the Mindset SEP Seismometer with the surface broadband Guralp seismometer located some 10 km to the south-west, but still in Brussels. We finally show results of small workshops that were organised within the school and the different school projects in preparation.

  3. Research in seismology and earthquake engineering in Venezuela

    USGS Publications Warehouse

    Urbina, L.; Grases, J.

    1983-01-01

    After the July 29, 1967, damaging earthquake (with a moderate magnitude of 6.3) caused widespread damage to the northern coastal area of Venezuela and to the Caracas Valley, the Venezuelan Government decided to establish a Presidential Earthquake Commission. This commission undertook the task of coordinating the efforts to study the after-effects of the earthquake. The July 1967 earthquake claimed numerous lives and caused extensive damage to the capital of Venezuela. In 1968, the U.S Geological Survey conducted a seismological field study in the northern coastal area and in the Caracas Valley of Venezuela. the objective was to study the area that sustained severe, moderate, and no damage to structures. A reported entitled Ground Amplification Studies in Earthquake Damage Areas: The Caracas Earthquake of 1967 documented, for the first time, short-period seismic wave ground-motion amplifications in the Caracas Valley. Figure 1 shows the area of severe damage in the Los Palos Grantes suburb and the correlation with depth of alluvium and the arabic numbers denote the ground amplification factor at each site in the area. the Venezuelan Government initiated many programs to study in detail the damage sustained and to investigate the ongoing construction practices. These actions motivated professionals in the academic, private, and Government sectors to develops further capabilities and self-sufficiency in the fields of engineering and seismology. Allocation of funds was made to assist in training professionals and technicians and in developing new seismological stations and new programs at the national level in earthquake engineering and seismology. A brief description of the ongoing programs in Venezuela is listed below. these programs are being performed by FUNVISIS and by other national organizations listed at the end of this article.   

  4. The effect of light-activation sources on tooth bleaching

    PubMed Central

    Baroudi, Kusai; Hassan, Nadia Aly

    2014-01-01

    Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching. PMID:25298598

  5. Brain activity underlying encoding and retrieval of source memory.

    PubMed

    Cansino, Selene; Maquet, Pierre; Dolan, Raymond J; Rugg, Michael D

    2002-10-01

    Neural activity elicited during the encoding and retrieval of source information was investigated with event-related functional magnetic resonance imaging (efMRI). During encoding, 17 subjects performed a natural/artificial judgement on pictures of common objects which were presented randomly in one of the four quadrants of the display. At retrieval, old pictures were mixed with new ones and subjects judged whether each picture was new or old and, if old, indicated in which quadrant it was presented at encoding. During encoding, study items that were later recognized and assigned a correct source judgement elicited greater activity than recognized items given incorrect judgements in a variety of regions, including right lateral occipital and left prefrontal cortex. At retrieval, regions showing greater activity for recognized items given correct versus incorrect source judgements included the right hippocampal formation and the left prefrontal cortex. These findings indicate a role for these regions in the encoding and retrieval of episodic information beyond that required for simple item recognition. PMID:12217968

  6. An event database for rotational seismology

    NASA Astrophysics Data System (ADS)

    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.

  7. Seismological constraints on lithospheric structure beneath rifted margins

    NASA Astrophysics Data System (ADS)

    Fishwick, Stewart

    2014-05-01

    There is considerable variation in both topography and crustal architecture along passive margins worldwide. However, the variations in lithospheric mantle structure are less well studied. This is, perhaps, in part due to the technical challenge for offshore-onshore passive seismology and also the lower resolution obtained in most mantle studies, particularly when compared to detailed imaging of the crust available from reflection seismology. The available large scale observations of mantle structure (predominately from surface waves), and crustal structure (from receiver functions) for the continental region adjacent to the margins are reviewed. Results for Africa and Australia show clear correlations between the mantle structure and the present day topography of the margin, and this relationship is explored from a worldwide perspective. Seismic studies can also provide information on lithospheric thickness at the margin, which can be used as an additional constraint for the thermal modelling of basin structure. In this case the limitations include the depth resolution of the method, and the particular proxy used to extract a lithospheric thickness estimate from a seismic model. Perhaps most importantly, is to remember that these seismological observations tell us only the existing structure. The challenge remains how to decipher whether the present structures relate to inherited pre-rift architecture; to alteration of lithospheric mantle during rifting, or to much later post rift changes associated with separate tectonic events.

  8. Innovative Seismological Techniques for Investigating the Interior Structure of Venus

    NASA Astrophysics Data System (ADS)

    Stevenson, D. J.; Cutts, J. A.; Mimoun, D.

    2014-12-01

    The formation, evolution and structure of Venus remain a mystery more than fifty years after the first visit by a robotic spacecraft. Radar images have revealed a surface that is much younger than those of the Moon, Mercury and Mars as well as a variety of enigmatic volcanic and tectonic features quite unlike those generated by plate tectonics on Earth. To understand how Venus works as a planet it is necessary to probe the interior of Venus. To accomplish this seismology must play a key role. Conventional seismology employs sensors in contact with the planetary surface but for Venus theses sensors must tolerate the Venus environment (460oC and 90 bars) for up to a year. The dense atmosphere of Venus, which efficiently couples seismic energy into the atmosphere as infrasonic waves, enables an alternative: detection of infrasonic waves in the upper atmosphere using either high altitude balloons or orbiting spacecraft. In June 2014, the Keck Institute for Space Studies (KISS) at the California Institute of Technology sponsored a one week workshop with 30 specialists in the key techniques and technologies that can bring these technique to readiness. In this paper, we describe the key synergies with earth science drawing on methods from terrestrial seismology and oceanography and identify key technical issues that need to be solved as well as important precursor measurements that should be made.

  9. EPOS-S: Integrated access to seismological waveforms

    NASA Astrophysics Data System (ADS)

    Sleeman, Reinoud; Strollo, Angelo; Michelini, Alberto; Clinton, John; Gueguen, Philippe; Luzi, Lucia; Pinar, Ali; Diaz, Jordi; Ceken, Ulubey; Evangelidis, Christos; Haslinger, Florian

    2016-04-01

    The main challenges of the EPOS TCS Seismology are to improve and to extend existing services to access earthquake waveforms (ORFEUS), parameters (EMSC) and hazard data and products (EFEHR), and producing a single framework that is technically integrated within the EPOS architecture. Technical developments in the services for seismological waveforms and associated data, including the compilation of station metadata and installing common data archival and sharing policies are within ORFEUS and its Working Groups. The focus is on 1) the development of the next generation software architecture for the European Integrated (seismological) Data Archive EIDA based on standardized webservices, the implementation of a data quality service and the realisation of a mediator service; 2) the development of EIDA-compliant services for strong motion data and acceleration data and the extension of the station metadata model; 3) the integration of data from mobile networks and OBS waveforms into EIDA by implementing mechanisms for coordination of transnational access and multinational experiments at available pools of OBS and mobile seismic stations; 4) achieve close integration with other EPOS TCS and the ICS with regard to interoperability and common use of tools & services, common and coordinated data models and metadata formats, and common computational platforms and IT solution implementations. This presentation will present the status of and current developments towards the above objectives.

  10. Twenty years of Alaska Volcano Observatory's contributions to seismology

    NASA Astrophysics Data System (ADS)

    Dixon, J. P.; McNutt, S. R.; Power, J. A.; West, M.

    2008-12-01

    The Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, the Geophysical Institute at the University of Alaska Fairbanks, and the Alaska Division of Geological and Geophysical Surveys observed its 20th anniversary in 2008. The AVO seismic network, inherited from AVO partners in 1988, consisted of three small-aperture subnetworks on Mount Spurr, Redoubt Volcano and Augustine Volcano and regional stations for a total of 23 short-period instruments (two with three-components). Twenty years later, the AVO network has expanded to 192 stations (23 three-component short-period, and 15 broadband) on 33 volcanoes spanning 2500 km across the Aleutian arc in one of the most remote and challenging environments in the world. The AVO seismic network provides for a unique data set. Within the seismically active Aleutian Arc, there are instrumented volcanoes which exhibit a variety of chemical compositions and eruptive styles. With each individual volcanic center similarly instrumented and all data analyzed in a consistent manner AVO has produced a data set suitable for making seismic comparisons across a wide suite of volcanoes. In twenty years, the AVO has captured data sets for eruptions at Augustine, Kasatochi, Okmok, Pavlof, Redoubt, Shishaldin, Spurr, and Venianinof. AVO data set also includes several volcanic-tectonic swarms, most notably at Akutan, Iliamna, Mageik, Martin, Shishaldin, and Tanaga. This broad approach to volcano seismology has led to a better understanding of precursory earthquake swarms, variations in background rates, triggered seismicity, the structure of volcanoes, volcanic tremor and deep long period earthquakes, among numerous other topics. The AVO also incorporates data from seismic stations operated by both the Alaska Earthquake Information Center and West Coast and Alaska Tsunami Warning Center to help locate some of the 70,000 earthquakes in the AVO catalog. In exchange AVO provides dense seismic data from the

  11. Observational and theoretical investigations in solar seismology

    NASA Technical Reports Server (NTRS)

    Noyes, Robert W.

    1992-01-01

    This is the final report on a project to develop a theoretical basis for interpreting solar oscillation data in terms of the interior dynamics and structure of the Sun. The topics covered include the following: (1) studies of the helioseismic signatures of differential rotation and convection in the solar interior; (2) wave generation by turbulent convection; and (3) the study of antipodal sunspot imaging of an active region tomography.

  12. Prevalent flucocorticoid and androgen activity in US water sources

    USGS Publications Warehouse

    Stavreva, Diana A.; George, Anuja A.; Klausmeyer, Paul; Varticovski, Lyuba; Sack, Daniel; Voss, Ty C.; Schiltz, R. Louis; Blazer, Vicki; Iwanowiczl, Luke R.; Hager, Gordon L.

    2012-01-01

    Contamination of the environment with endocrine disrupting chemicals (EDCs) is a major health concern. The presence of estrogenic compounds in water and their deleterious effect are well documented. However, detection and monitoring of other classes of EDCs is limited. Here we utilize a high-throughput live cell assay based on sub-cellular relocalization of GFP-tagged glucocorticoid and androgen receptors (GFP-GR and GFP-AR), in combination with gene transcription analysis, to screen for glucocorticoid and androgen activity in water samples. We report previously unrecognized glucocorticoid activity in 27%, and androgen activity in 35% of tested water sources from 14 states in the US. Steroids of both classes impact body development, metabolism, and interfere with reproductive, endocrine, and immune systems. This prevalent contamination could negatively affect wildlife and human populations.

  13. Prevalent Glucocorticoid and Androgen Activity in US Water Sources

    PubMed Central

    Stavreva, Diana A.; George, Anuja A.; Klausmeyer, Paul; Varticovski, Lyuba; Sack, Daniel; Voss, Ty C.; Schiltz, R. Louis; Blazer, Vicki S.; Iwanowicz, Luke R.; Hager, Gordon L.

    2012-01-01

    Contamination of the environment with endocrine disrupting chemicals (EDCs) is a major health concern. The presence of estrogenic compounds in water and their deleterious effect are well documented. However, detection and monitoring of other classes of EDCs is limited. Here we utilize a high-throughput live cell assay based on sub-cellular relocalization of GFP-tagged glucocorticoid and androgen receptors (GFP-GR and GFP-AR), in combination with gene transcription analysis, to screen for glucocorticoid and androgen activity in water samples. We report previously unrecognized glucocorticoid activity in 27%, and androgen activity in 35% of tested water sources from 14 states in the US. Steroids of both classes impact body development, metabolism, and interfere with reproductive, endocrine, and immune systems. This prevalent contamination could negatively affect wildlife and human populations. PMID:23226835

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Hollow cathode plasma source for active spacecraft charge control

    NASA Technical Reports Server (NTRS)

    Deininger, William D.; Aston, Graeme; Pless, Lewis C.

    1987-01-01

    A prototype plasma source spacecraft discharge device has been developed to control overall and differential spacecraft surface charging. The plasma source is based on a unique hollow cathode discharge, where the plasma generation process is contained completely within the cathode. This device can be operated on argon, krypton, or xenon and has a rapid cold start time of less than 4 s. The discharge system design includes a spacecraft-discharge/net-charge sensing circuit which provides the ability to measure the polarity, magnitude, pulse shape, and time duration of a discharging event. Ion currents of up to 325 microA and electron currents ranging from 0.02 to 6.0 A have been extracted from the device. In addition, the spacecraft discharge device successfully discharged capacitively biased plates, from as high as + or - 2500 V, to ground potential, and discharged and clamped actively biased plates at +5 V with respect to ground potential during ground simulation testing.

  16. CSDP: The seismology of continental thermal regimes

    SciTech Connect

    Aki, K.

    1991-05-01

    The past year continued to be extremely productive following up two major breakthroughs made in the preceding year. One of the breakthroughs was the derivation of an integral equation for time- dependent power spectra, which unified all the existing theories on seismic scattering including the radiative transfer theory for total energy and single-multiple scattering theories based on the ray approach. We successfully applied the method to the data from the USGS regional seismic arrays in central California, Long Valley and Island of Hawaii, and obtained convincing results on the scattering Q{sup {minus}1} and intrinsic Q{sup {minus}1} in these areas for the frequency range from 1 Hz to 20 Hz. The frequency dependence of scattering Q{sup {minus}1} is, then, interpreted in terms of random medium with continuous or discrete scatterers. The other breakthrough was the application of T-matrix formulation to the seismic scattering problem. We are currently working on 2-dimensional inclusions with high and low velocity contrast with the surrounding medium. In addition to the above two main lines of research, we were able to use so-called T-phase'' observed on the Island of Hawaii to map the Q value with a good spatial resolution. We found that we can eliminate remarkably well the frequency dependent recording site effect from the T-phase amplitude using the amplification factor for coda waves, further confirming the fundamental separability of source, path and site effects for coda waves, and proving the effectiveness of stochastic modeling of high-frequency seismic waves. 70 refs., 24 figs.

  17. Seismology of Convection in the Sun

    NASA Astrophysics Data System (ADS)

    Hanasoge, Shravan

    2015-08-01

    Solar convection lies in extraordinary regime of dynamical parameters. Convective processes in the Sun drive global fluid circulations and magnetic fields, which in turn affect its visible outer layers (solar activity) and, more broadly, the heliosphere (space weather). The precise determination of the depth of solar convection zone, departures from adiabaticity of the temperature gradient, and the internal rotation rate as a function of latitude and depth are among the seminal contributions of helioseismology towards understanding convection in the Sun. Contemporary helioseismology, which is focused on inferring the properties of three-dimensional convective features, suggests that transport velocities are substantially smaller than theoretical predictions. Furthermore, helioseismology provides important constraints on the anisotropic Reynolds stresses that control the global dynamics of the solar convection zone. In this review, I will discuss the state of our understanding of convection in the Sun, with a focus on helioseismic diagnostics.

  18. Broadband seismology and small regional seismic networks

    USGS Publications Warehouse

    Herrmann, Robert B.

    1995-01-01

    In the winter of 1811-12, three of the largest historic earthquakes in the United States occurred near New Madrid, Missouri. Seismicity continues to the present day throughout a tightly clustered pattern of epicenters centered on the bootheel of Missouri, including parts of northeastern Arkansas, northwestern Tennessee, western Kentucky, and southern Illinois. In 1990, the New Madrid seismic zone/Central United States became the first seismically active region east of the Rocky Mountains to be designated a priority research area within the National Earthquake Hazards Reduction Program (NEHRP). This Professional Paper is a collection of papers, some published separately, presenting results of the newly intensified research program in this area. Major components of this research program include tectonic framework studies, seismicity and deformation monitoring and modeling, improved seismic hazard and risk assessments, and cooperative hazard mitigation studies.

  19. MOZART - A seismological investigation of Central Mozambique

    NASA Astrophysics Data System (ADS)

    Domingues, Ana; Chamussa, Jose; Helffrich, George; Fishwick, Stewart; Ferreira, Ana; Custodio, Susana; Silveira, Graca; Manhica, Vladimiro; Fonseca, Joao

    2013-04-01

    Project MOZART (MOZAmbique Rift Tomography) aims to investigate the geological structure and current tectonic activity of the Mozambique sector of the East African Rift System (EARS). Space geodesy has indicated in recent years that the border between Nubia and the Somalian plate at these latitudes (16°S to 24°S) encompasses the Rovuma microplate, but little is known about its geometry or seismotectonics. The M7 Machaze earthquake of 2006 highlighted the relevance of the associated deformation, and motivated the MOZART deployment. Besides the regional seismotectonics, other targets of the project are the illumination of the Mesoproterozoic structures of the Mozambique Belt, and the study of its role in the current incipient rifting. The seismic network is composed of 30 VBB seismographic stations on loan from NERC's SEIS-UK Pool (Guralp CMG-3T 120s sensors) covering Central Mozambique (Manica, Sofala, Gaza and Inhambane provinces) with average inter-station spaces of the order of 100 km. Four stations are across the border in South Africa (Kruger Park). Data acquisition started in March 2011, and decommissioning is foreseen for August 2013. Data processing is underway, and includes local seismicity analysis, receiver function estimation and the study of surface wave dispersion (both ambient noise and teleseismic). Once a preliminary velocity model is developed with these techniques, further refinements will be attempted through waveform tomography. For this purpose, SPECFEM waveform modelling with a 3D velocity model is currently being implemented. Preliminary results of the ongoing data processing and analysis will be presented.

  20. Verification of Minimum Detectable Activity for Radiological Threat Source Search

    NASA Astrophysics Data System (ADS)

    Gardiner, Hannah; Myjak, Mitchell; Baciak, James; Detwiler, Rebecca; Seifert, Carolyn

    2015-10-01

    The Department of Homeland Security's Domestic Nuclear Detection Office is working to develop advanced technologies that will improve the ability to detect, localize, and identify radiological and nuclear sources from airborne platforms. The Airborne Radiological Enhanced-sensor System (ARES) program is developing advanced data fusion algorithms for analyzing data from a helicopter-mounted radiation detector. This detector platform provides a rapid, wide-area assessment of radiological conditions at ground level. The NSCRAD (Nuisance-rejection Spectral Comparison Ratios for Anomaly Detection) algorithm was developed to distinguish low-count sources of interest from benign naturally occurring radiation and irrelevant nuisance sources. It uses a number of broad, overlapping regions of interest to statistically compare each newly measured spectrum with the current estimate for the background to identify anomalies. We recently developed a method to estimate the minimum detectable activity (MDA) of NSCRAD in real time. We present this method here and report on the MDA verification using both laboratory measurements and simulated injects on measured backgrounds at or near the detection limits. This work is supported by the US Department of Homeland Security, Domestic Nuclear Detection Office, under competitively awarded contract/IAA HSHQDC-12-X-00376. This support does not constitute an express or implied endorsement on the part of the Gov't.

  1. Retrieving the Stress Field Within the Campi Flegrei Caldera (Southern Italy) Through an Integrated Geodetical and Seismological Approach

    NASA Astrophysics Data System (ADS)

    D'Auria, Luca; Massa, Bruno; Cristiano, Elena; Del Gaudio, Carlo; Giudicepietro, Flora; Ricciardi, Giovanni; Ricco, Ciro

    2015-11-01

    We investigated the Campi Flegrei caldera using a quantitative approach to retrieve the spatial and temporal variations of the stress field. For this aim we applied a joint inversion of geodetic and seismological data to a dataset of 1,100 optical levelling measurements and 222 focal mechanisms, recorded during the bradyseismic crisis of 1982-1984. The inversion of the geodetic dataset alone, shows that the observed ground deformation is compatible with a source consisting of a planar crack, located at the centre of the caldera at a depth of about 2.56 km and a size of about 4 × 4 km. Inversion of focal mechanisms using both analytical and graphical approaches, has shown that the key features of the stress field in the area are: a nearly subvertical σ 1 and a sub-horizontal, roughly NNE-SSW trending σ 3. Unfortunately, the modelling of the stress fields based only upon the retrieved ground deformation source is not able to fully account for the stress pattern delineated by focal mechanism inversion. The introduction of an additional regional background field has been necessary. This field has been determined by minimizing the difference between observed slip vectors for each focal mechanism and the theoretical maximum shear stress deriving from both the volcanic (time-varying) and the regional (constant) field. The latter is responsible for a weak NNE-SSW extension, which is consistent with the field determined for the nearby Mt. Vesuvius volcano. The proposed approach accurately models observations and provides interesting hints to better understand the dynamics of the volcanic unrest and seismogenic processes at Campi Flegrei caldera. This procedure could be applied to other volcanoes experiencing active ground deformation and seismicity.

  2. Seismological Field Observation of Mesoscopic Nonlinearity

    NASA Astrophysics Data System (ADS)

    Sens-Schönfelder, Christoph; Gassenmeier, Martina; Eulenfeld, Tom; Tilmann, Frederik; Korn, Michael; Niederleithinger, Ernst

    2016-04-01

    Noise based observations of seismic velocity changes have been made in various environments. We know of seasonal changes of velocities related to ground water or temperature changes, co-seismic changes originating from shaking or stress redistribution and changes related to volcanic activity. Is is often argued that a decrease of velocity is related to the opening of cracks while the closure of cracks leads to a velocity increase if permanent stress changes are invoked. In contrast shaking induced changes are often related to "damage" and subsequent "healing" of the material. The co-seismic decrease and transient recovery of seismic velocities can thus be explained with both - static stress changes or damage/healing processes. This results in ambiguous interpretations of the observations. Here we present the analysis of one particular seismic station in northern Chile that shows very strong and clear velocity changes associated with several earthquakes ranging from Mw=5.3 to Mw=8.1. The fact that we can observe the response to several events of various magnitudes from different directions offers the unique possibility to discern the two possible causative processes. We test the hypothesis, that the velocity changes are related to shaking rather than stress changes by developing an empirical model that is based on the local ground acceleration at the sensor site. The eight year of almost continuous observations of velocity changes are well modeled by a daily drop of the velocity followed by an exponential recovery. Both, the amplitude of the drop as well as the recovery time are proportional to the integrated acceleration at the seismic station. Effects of consecutive days are independent and superimposed resulting in strong changes after earthquakes and constantly increasing velocities during quiet days thereafter. This model describes the continuous observations of the velocity changes solely based on the acceleration time series without individually defined dates

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

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

    success of the programme was targeting teachers who would be committed to its implementation and promotion in the school. Strong emphasis by DIAS was placed on providing teacher training days on the set-up and operation of the seismometer, and they were also trained in various animation software programmes used to enhance the learning capacities of the students in the classroom. Regular contact is maintained with the teachers in the programme throughout the academic year to support and encourage their work in the classroom. Teachers receive an SMS alert message from DIAS when an earthquake of Mag 5 has been recorded by the Irish National Seismic network which will then form part of the next lesson plan for Geography and Maths in the curriculum. Most participating schools have become affiliated to the IRIS International Schools Seismic Network site, and students upload the waveform seismic data in SAC format for the recorded seismic events at their school to share with schools internationally. Future developments in the programme will include the investigation of twinning of schools on different continents who are actively pursuing a seismology in schools programme.

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

    NASA Astrophysics Data System (ADS)

    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.

  5. Seismological aspects of the 27 June 2015 Gulf of Aqaba earthquake and its sequence of aftershocks

    NASA Astrophysics Data System (ADS)

    Abd el-aal, Abd el-aziz Khairy; Badreldin, Hazem

    2016-04-01

    On 27 June 2015, a moderate earthquake with magnitude Mb 5.2 struck the Gulf of Aqaba near Nuweiba City. This event was instrumentally recorded by the Egyptian National Seismic Network (ENSN) and many other international seismological centres. The event was felt in all the cities on the Gulf of Aqaba, as well as Suez City, Hurghada City, the greater Cairo Metropolitan Area, Israel, Jordan and the north-western part of Saudi Arabia. No casualties were reported, however. Approximately 95 aftershocks with magnitudes ranging from 0.7 to 4.2 were recorded by the ENSN following the mainshock. In the present study, the source characteristics of both the mainshock and the aftershocks were estimated using the near-source waveform data recorded by the very broadband stations of the ENSN, and these were validated by the P-wave polarity data from short period stations. Our analysis reveals that an estimated seismic moment of 0.762 × 1017 Nm was released, corresponding to a magnitude of Mw 5.2, a focal depth of 14 km, a fault radius of 0.72 km and a rupture area of approximately 1.65 km2. Monitoring the sequence of aftershocks reveals that they form a cluster around the mainshock and migrated downwards in focal depth towards the west. We compared the results we obtained with the published results from the international seismological centres. Our results are more realistic and accurate, in particular with respect to the epicenteral location, magnitude and fault plane solution which are in accordance with the hypocentre distribution of the aftershocks.

  6. Seismological aspects of the 27 June 2015 Gulf of Aqaba earthquake and its sequence of aftershocks

    NASA Astrophysics Data System (ADS)

    Abd el-aal, Abd el-aziz Khairy; Badreldin, Hazem

    2016-07-01

    On 27 June 2015, a moderate earthquake with magnitude Mb 5.2 struck the Gulf of Aqaba near Nuweiba City. This event was instrumentally recorded by the Egyptian National Seismic Network (ENSN) and many other international seismological centres. The event was felt in all the cities on the Gulf of Aqaba, as well as Suez City, Hurghada City, the greater Cairo Metropolitan Area, Israel, Jordan and the north-western part of Saudi Arabia. No casualties were reported, however. Approximately 95 aftershocks with magnitudes ranging from 0.7 to 4.2 were recorded by the ENSN following the mainshock. In the present study, the source characteristics of both the mainshock and the aftershocks were estimated using the near-source waveform data recorded by the very broadband stations of the ENSN, and these were validated by the P-wave polarity data from short period stations. Our analysis reveals that an estimated seismic moment of 0.762 × 1017 Nm was released, corresponding to a magnitude of Mw 5.2, a focal depth of 14 km, a fault radius of 0.72 km and a rupture area of approximately 1.65 km2. Monitoring the sequence of aftershocks reveals that they form a cluster around the mainshock and migrated downwards in focal depth towards the west. We compared the results we obtained with the published results from the international seismological centres. Our results are more realistic and accurate, in particular with respect to the epicenteral location, magnitude and fault plane solution which are in accordance with the hypocentre distribution of the aftershocks.

  7. Ensemble approaches to structural seismology: seek many rather than one

    NASA Astrophysics Data System (ADS)

    Sambridge, M.; Bodin, T.; Tkalcic, H.; Gallagher, K.

    2011-12-01

    For the past forty years seismologists have built models of the Earth's seismic structure over local, regional and global distance scales using derived quantities of a seismogram covering the frequency spectrum. A feature common to (almost) all cases is the objective of building a single `best' Earth model, in some sense. This is despite the fact that the data by themselves often do not require, or even allow, a single best fit Earth model to exist. It is widely recognized that many seismic inverse problems are ill-posed and non-unique and hence require regularization or additional constraints to obtain a single structural model. Interpretation of optimal models can be fraught with difficulties, particularly when formal uncertainty estimates become heavily dependent on the regularization imposed. An alternative approach is to embrace the non-uniqueness directly and employ an inference process based on parameter space sampling. Instead of seeking a best model within an optimization framework one seeks an ensemble of solutions and derives properties of that ensemble for inspection. While this idea has itself been employed for more than 30 years, it is not commonplace in seismology. Recent work has shown that trans-dimensional and hierarchical sampling methods have some considerable benefits for seismological problems involving multiple parameter types, uncertain data errors and/or uncertain model parameterizations. Rather than being forced to make decisions on parameterization, level of data noise and weights between data types in advance, as is often the case in an optimization framework, these choices can be relaxed and instead constrained by the data themselves. Limitations exist with sampling based approaches in that computational cost is often considered to be high for large scale structural problems, i.e. many unknowns and data. However there are a surprising number of areas where they are now feasible. This presentation will describe recent developments in

  8. How the use of statistical seismology benefits induced seismicity research

    NASA Astrophysics Data System (ADS)

    Bachmann, C. E.; Wiemer, S.; Allmann, B.; Mena Cabrera, B.; Woessner, J.

    2012-12-01

    b-values change from higher values close to the injection points to lower values further out. Additionally, the b-value changes from high values during the fluid injection to lower values later on. A model, simulating the pore pressure diffusion and relating the event-sizes to the differential stress via an inverse relationship established for tectonic events, aims to evaluate this observation of the b-value distribution. The model implies that high pore pressures lead to high b-values as preferably events with smaller sizes are induced. Moderate pressures lead to values of b similar to the regional average. Since pore pressures decline as a function of distance to the injection point, the probability of observing a large magnitude event thus increases with distance. We are therefore able to establish a link between the seismological observables and the geomechanical properties of the source region and thus a reservoir. Understanding the geomechanical properties is essential for estimating the probability of exceeding a certain magnitude value in the induced seismicity and hence the associated seismic hazard of the operation.

  9. Magnetohydrodynamic waves and coronal seismology: an overview of recent results.

    PubMed

    De Moortel, Ineke; Nakariakov, Valery M

    2012-07-13

    Recent observations have revealed that magnetohydrodynamic (MHD) waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology that have recently been the focus of intense debate or are newly emerging. In particular, we focus on four topics: (i) the current controversy surrounding propagating intensity perturbations along coronal loops, (ii) the interpretation of propagating transverse loop oscillations, (iii) the ongoing search for coronal (torsional) Alfvén waves, and (iv) the rapidly developing topic of quasi-periodic pulsations in solar flares. PMID:22665899

  10. Establishing The Pasadena Seismological Laboratory: An Adventure in Scientific Collaboration

    NASA Astrophysics Data System (ADS)

    Hazen, M. H.

    2002-05-01

    The 1906 San Francisco earthquake jolted Berkeley geologist Harry O. Wood (1879-1958) into a lifetime of seismological research that included the establishment of a seismic monitoring network in southern California, the co-invention of a seismograph capable of measuring short-period earthquakes, and the implementation of a public-safety campaign. None of these initiatives would have been possible without the support of the Carnegie Institution, a Washington DC-based research organization that supported not only exceptional individuals (as founder Andrew Carnegie had stipulated), but also large-scale, collaborative investigations. Wood published his plan for a "western United States" earthquake research program in 1916, but it was not until he moved to Washington during World War I that he made contacts that transformed his dream into a reality. While working at the National Research Council, Wood shared his vision with astronomer George Ellery Hale, geologist Arthur L. Day and, finally, Carnegie president John C. Merriam. Merriam was a Californian, a geologist, and a strong proponent of collaborative science. In 1921, the Carnegie Advisory Committee on Seismology - the first organization "of this magnitude" in American research - was formed. Initially, the program operated from an office at the Mount Wilson Observatory, where Wood was in charge of the daily operations. Then, in 1926, a joint venture with the California Institute of Technology was launched. Located in the mountains west of Pasadena, the Seismological Laboratory coordinated a range of scientific efforts. By 1930, thirteen American cities had Wood-Anderson seismographs in place, quantities of data had been acquired, new fault zones had been identified, and Beno Gutenberg and Charles F. Richter had been attracted to the program. Over the years, the U.S. Coast and Geodetic Survey and other government agencies also contributed to the effort. In the mid-1930s, the Carnegie Institution transferred the

  11. GROUNDWATER QUALITY MONITORING OF WESTERN COAL STRIP MINING: PRELIMINARY DESIGNS FOR ACTIVE MINE SOURCES OF POLLUTION

    EPA Science Inventory

    Three potential pollution source categories have been identified for Western coal strip mines. These sources include mine stockpiles, mine waters, and miscellaneous active mine sources. TEMPO's stepwise monitoring methodology (Todd et al., 1976) is used to develop groundwater qua...

  12. Orally active opioid compounds from a non-poppy source.

    PubMed

    Raffa, Robert B; Beckett, Jaclyn R; Brahmbhatt, Vivek N; Ebinger, Theresa M; Fabian, Chrisjon A; Nixon, Justin R; Orlando, Steven T; Rana, Chintan A; Tejani, Ali H; Tomazic, Robert J

    2013-06-27

    The basic science and clinical use of morphine and other "opioid" drugs are based almost exclusively on the extracts or analogues of compounds isolated from a single source, the opium poppy (Papaver somniferum). However, it now appears that biological diversity has evolved an alternative source. Specifically, at least two alkaloids isolated from the plant Mitragyna speciosa, mitragynine ((E)-2-[(2S,3S)-3-ethyl-8-methoxy-1,2,3,4,6,7,12,12b-octahydroindolo[3,2-h]quinolizin-2-yl]-3-methoxyprop-2-enoic acid methyl ester; 9-methoxy coryantheidine; MG) and 7-hydroxymitragynine (7-OH-MG), and several synthetic analogues of these natural products display centrally mediated (supraspinal and spinal) antinociceptive (analgesic) activity in various pain models. Several characteristics of these compounds suggest a classic "opioid" mechanism of action: nanomolar affinity for opioid receptors, competitive interaction with the opioid receptor antagonist naloxone, and two-way analgesic cross-tolerance with morphine. However, other characteristics of the compounds suggest novelty, particularly chemical structure and possible greater separation from side effects. We review the chemical and pharmacological properties of these compounds. PMID:23517479

  13. Antiglycation Activity of Iridoids and Their Food Sources

    PubMed Central

    West, Brett J.; Uwaya, Akemi; Isami, Fumiyuki; Deng, Shixin; Nakajima, Sanae; Jensen, C. Jarakae

    2014-01-01

    Iridoids are dietary phytochemicals that may have the ability to inhibit the formation of advanced glycation end products (AGEs). Three studies were conducted to investigate this anti-AGE potential. First, the inhibition of fluorescence intensity by food-derived iridoids, after 4 days of incubation with bovine serum albumin, glucose, and fructose, was used to evaluate in vitro antiglycation activity. Next, an 8-week open-label pilot study used the AGE Reader to measure changes in the skin autofluorescence of 34 overweight adults who consumed daily a beverage containing food sources of iridoids. Finally, a cross-sectional population study with 3913 people analyzed the relationship between daily iridoid intake and AGE accumulation, as measured by skin autofluorescence with the TruAge scanner. In the in vitro test, deacetylasperulosidic acid and loganic acid both inhibited glycation in a concentration-dependent manner, with respective IC50 values of 3.55 and 2.69 mM. In the pilot study, average skin autofluorescence measurements decreased by 0.12 units (P < 0.05). The cross-sectional population survey revealed that, for every mg of iridoids consumed, there is a corresponding decline in AGE associated age of 0.017 years (P < 0.0001). These results suggest that consumption of dietary sources of iridoids may be a useful antiaging strategy. PMID:26904624

  14. Source localization of brain activity using helium-free interferometer

    NASA Astrophysics Data System (ADS)

    Dammers, Jürgen; Chocholacs, Harald; Eich, Eberhard; Boers, Frank; Faley, Michael; Dunin-Borkowski, Rafal E.; Jon Shah, N.

    2014-05-01

    To detect extremely small magnetic fields generated by the human brain, currently all commercial magnetoencephalography (MEG) systems are equipped with low-temperature (low-Tc) superconducting quantum interference device (SQUID) sensors that use liquid helium for cooling. The limited and increasingly expensive supply of helium, which has seen dramatic price increases recently, has become a real problem for such systems and the situation shows no signs of abating. MEG research in the long run is now endangered. In this study, we report a MEG source localization utilizing a single, highly sensitive SQUID cooled with liquid nitrogen only. Our findings confirm that localization of neuromagnetic activity is indeed possible using high-Tc SQUIDs. We believe that our findings secure the future of this exquisitely sensitive technique and have major implications for brain research and the developments of cost-effective multi-channel, high-Tc SQUID-based MEG systems.

  15. Source localization of brain activity using helium-free interferometer

    SciTech Connect

    Dammers, Jürgen Chocholacs, Harald; Eich, Eberhard; Boers, Frank; Faley, Michael; Dunin-Borkowski, Rafal E.; Jon Shah, N.

    2014-05-26

    To detect extremely small magnetic fields generated by the human brain, currently all commercial magnetoencephalography (MEG) systems are equipped with low-temperature (low-T{sub c}) superconducting quantum interference device (SQUID) sensors that use liquid helium for cooling. The limited and increasingly expensive supply of helium, which has seen dramatic price increases recently, has become a real problem for such systems and the situation shows no signs of abating. MEG research in the long run is now endangered. In this study, we report a MEG source localization utilizing a single, highly sensitive SQUID cooled with liquid nitrogen only. Our findings confirm that localization of neuromagnetic activity is indeed possible using high-T{sub c} SQUIDs. We believe that our findings secure the future of this exquisitely sensitive technique and have major implications for brain research and the developments of cost-effective multi-channel, high-T{sub c} SQUID-based MEG systems.

  16. Seismologically determined bedload flux during the typhoon season

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

    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.

  17. Seismology and lateral thickness variations of the lunar crust

    NASA Astrophysics Data System (ADS)

    Chenet, H.; Lognonné, P.; Wieczorek, M.; Mizutani, H.

    The Apollo missions set up a seismic network on the nearside of the Moon (1969-1977), which allowed to address the fundamental questions of lunar science. Recently this dataset was re-investigated in order to shed light on ambiguous results of ancient studies. One of them was the proposed 60 km crustal thickness below the Apollo station 12 and 14 sites. Today, Khan and Mosegaard (2002) and Lognonné et al. (2003), both propose that the crust is much thinner than expected, respectively around 45 and 30 km. On the other hand, lateral relative variations of crustal thickness can be determined by inversion of gravity and topography data, but this process requires the use of a reference thickness brought by seismic determination, in order to build a crustal thickness map. This present work goes further. In this study, we constrain for the first time the lateral variations of crustal thickness with seismic and topography data only. We use a Markov-Chain Monte-Carlo method to invert for the lateral crustal thickness, determined by the arrival times of impacts at the 4 Apollo stations. Each impact and station site is associated to an independent Moho depth. Thus, we find independent seismological constraints on the Moho depth for 30 different locations on the lunar surface instead of one. We will present here the results of this study via a comparison between this first lunar crustal thickness map we built with seismology, and the map resulting from analysis of the gravity data.

  18. Seismologically determined bedload flux during the typhoon season.

    PubMed

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

    2015-01-01

    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. PMID:25652082

  19. U.S./U.S.S.R. seismological network developing

    NASA Astrophysics Data System (ADS)

    Given, Holly

    In the spirit of glasnost, the first stage of a state-of-the-art seismological network for global research on Earth structure, earthquakes, and seismic monitoring of nuclear testing is now operating in the Soviet Union, thanks to cooperation between several U.S. and Soviet groups and agencies. Digitally recorded seismic data have been generally unavailable from the Soviet Union prior to the new agreement, leaving an essentially uninstrumented hole in the largest continent on Earth. In 1988 the Soviet Academy agreed to a joint research program with the Incorporated Research Institutions for Seismology (IRIS) and the U.S. Geological Survey that called for the establishment of 20-25 permanent seismic stations and the operation of portable seismic networks in each country. The U.S. State Department approved the incorporation of the seismic program, now called the Eurasian Seismic Studies Program, under Area IX (Earthquake Prediction) of the Bilateral U.S./U.S.S.R. Environmental Protection Agreement. The network is operated by IRIS, a consortium of over 60 American universities, the USGS, and the Institute of Physics of the Earth (IPE) of the Soviet Academy of Sciences. Principal project scientists are Jonathan Berger, a geophysicist at Scripps Institution of Oceanography, and John Filson, a seismologist at USGS.

  20. Seismological constraints on deep mantle structure: recent results

    NASA Astrophysics Data System (ADS)

    Ritsema, J. E.

    2002-12-01

    Thanks to the development of global seismic networks, especially in the past two decades when digital broadband ground motion sensors were employed, full waveform analysis has led to the development of three-dimensional models of the structure of Earth's interior. Yet, many of the new models confirm a number of critical conclusions that F. Birch drew in his seminal 1952 JGR paper. For example, he envisioned that the upper mantle transition zone plays a prominent role in mantle circulation and he emphasized the significant effect of pressure on thermodynamic parameters. Indeed, a large number of seismic studies of the transition zone indicate that the descent of slabs of former oceanic lithosphere is, with few exceptions, impeded by the 660--km discontinuity. Furthermore, the observation of predominantly broad seismic velocity structures in the lower mantle (> 1500 km depth) may reflect sluggish convection, due to reduced thermal expansivity. I will review several recent seismological studies of the deep mantle and place them in the context of Birch's paper. In particular, I will discuss surprising new findings in the deep mantle beneath Africa, which is especially well studied with data from recent African deployments. Furthermore, I will show results of the application of a new 3D waveform modeling technique that may prove invaluable in future seismological studies of the deep mantle.

  1. Seismologically determined bedload flux during the typhoon season

    PubMed Central

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

    2015-01-01

    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. PMID:25652082

  2. Curvelets for signal processing in seismology: an exploration perspective (Invited)

    NASA Astrophysics Data System (ADS)

    Hennenfent, G.

    2009-12-01

    The curvelet transform is a recent addition to the computational harmonic analysis toolbox. It expands an arbitrary 2-D signal as a series of weighted curvelets, much like, e.g., the Fourier or wavelet transform. Curvelets are localized and multiscale elements which are highly anisotropic at fine scales. They look like little band-limited plane waves, smooth along their main axis and oscillatory across. Curvelets provide a sparse representation—arguably the sparsest—for signals that are smooth except for discontinuities along smooth curves, e.g., natural images with edges or seismic wavefronts. This key property, combined with new insights from compressive sensing, lead to innovative applications in astronomy, medical imaging, and exploration seismology to name but a few. In this talk, we give a brief overview of the curvelet transform and its key properties. We discuss one of its discrete implementations, the fast discrete curvelet transform via wrapping, and our extension to nonequispaced data inputs. We conclude by a few examples of applications in seismology using curvelets.

  3. Integrating Seismology into the Physics Curriculum: An Opportunity to Introduce High-School Students to Scientific Research

    NASA Astrophysics Data System (ADS)

    Sayers, J.

    2002-12-01

    High school physics provides a natural vehicle for introducing seismology and geophysics concepts into the secondary science curriculum. Fundamental principles of mechanics and wave motion can be studied through investigation of the real-world phenomena of earthquakes and the seismic waves they generate. In turn, the excitement of a major earthquake and news media coverage stimulates student interest and involvement, especially if students are able to record the event. Too often, students' exposure to science has been confined to textbook work or "cookbook" lab exercises and they develop a very limited understanding of how science works. The National Science Standards, as well as many state standards, have emphasized the importance of hands-on inquiry-based activities, the use of real data and the introduction of research as fundamental to improving students' understanding of science. Students who run their own seismic station have the opportunity to experience the rewards and frustrations that can result from real scientific work. At Northview High School (Brazil, Indiana) we have installed a PEPP broadband seismometer in an external vault. Physics students are responsible for the day-to-day operation of the station. They download data and produce and post seismograms of earthquakes that have been recorded by the station and identified by the students. A hallway display case provides students, faculty and staff with a continuous (nearly) live display of the data being collected. The operation of the station has generated a great deal of student and community interest in the study of earthquakes. In this presentation, I will describe how seismology has been incorporated into the physics curriculum at Northview High School, and how our students have benefited from the opportunity to take part in hands-on scientific research. I will describe our participation in a regional seismic network through seismic data acquisition, data analysis using seismological software

  4. Pomegranate fruit as a rich source of biologically active compounds.

    PubMed

    Sreekumar, Sreeja; Sithul, Hima; Muraleedharan, Parvathy; Azeez, Juberiya Mohammed; Sreeharshan, Sreeja

    2014-01-01

    Pomegranate is a widely used plant having medicinal properties. In this review, we have mainly focused on the already published data from our laboratory pertaining to the effect of methanol extract of pericarp of pomegranate (PME) and have compared it with other relevant literatures on Punica. Earlier, we had shown its antiproliferative effect using human breast (MCF-7, MDA MB-231), and endometrial (HEC-1A), cervical (SiHa, HeLa), and ovarian (SKOV3) cancer cell lines, and normal breast fibroblasts (MCF-10A) at concentration of 20-320 μg/mL. The expressions of selected estrogen responsive genes (PR, pS2, and C-Myc) were downregulated by PME. Unlike estradiol, PME did not increase the uterine weight and proliferation in bilaterally ovariectomized Swiss-Albino mice models and its cardioprotective effects were comparable to that of 17 β -estradiol. We had further assessed the protective role of PME on skeletal system, using MC3T3-E1 cells. The results indicated that PME (80 μg/mL) significantly increased ALP (Alkaline Phosphatase) activity, supporting its suggested role in modulating osteoblastic cell differentiation. The antiosteoporotic potential of PME was also evaluated in ovariectomized (OVX) rodent model. The results from our studies and from various other studies support the fact that pomegranate fruit is indeed a source of biologically active compounds. PMID:24818149

  5. Tanshinones: Sources, Pharmacokinetics and Anti-Cancer Activities

    PubMed Central

    Zhang, Yong; Jiang, Peixin; Ye, Min; Kim, Sung-Hoon; Jiang, Cheng; Lü, Junxuan

    2012-01-01

    Tanshinones are a class of abietane diterpene compound isolated from Salvia miltiorrhiza (Danshen or Tanshen in Chinese), a well-known herb in Traditional Chinese Medicine (TCM). Since they were first identified in the 1930s, more than 40 lipophilic tanshinones and structurally related compounds have been isolated from Danshen. In recent decades, numerous studies have been conducted to investigate the isolation, identification, synthesis and pharmacology of tanshinones. In addition to the well-studied cardiovascular activities, tanshinones have been investigated more recently for their anti-cancer activities in vitro and in vivo. In this review, we update the herbal and alternative sources of tanshinones, and the pharmacokinetics of selected tanshinones. We discuss anti-cancer properties and identify critical issues for future research. Whereas previous studies have suggested anti-cancer potential of tanshinones affecting multiple cellular processes and molecular targets in cell culture models, data from in vivo potency assessment experiments in preclinical models vary greatly due to lack of uniformity of solvent vehicles and routes of administration. Chemical modifications and novel formulations had been made to address the poor oral bioavailability of tanshinones. So far, human clinical trials have been far from ideal in their design and execution for the purpose of supporting an anti-cancer indication of tanshinones. PMID:23202971

  6. A novel method for the activity measurement of large-area beta reference sources.

    PubMed

    Stanga, D; De Felice, P; Keightley, J; Capogni, M; Ioan, M R

    2016-03-01

    A novel method has been developed for the activity measurement of large-area beta reference sources. It makes use of two emission rate measurements and is based on the weak dependence between the source activity and the activity distribution for a given value of transmission coefficient. The method was checked experimentally by measuring the activity of two ((60)Co and (137)Cs) large-area reference sources constructed from anodized aluminum foils. Measurement results were compared with the activity values measured by gamma spectrometry. For each source, they agree within one standard uncertainty and also agree within the same limits with the certified values of the source activity. PMID:26701656

  7. Local network deployed around the Kozloduy NPP - a useful tool for seismological monitoring

    NASA Astrophysics Data System (ADS)

    Solakov, Dimcho; Simeonova, Stela; Dimitrova, Liliya; Slavcheva, Krasimira; Raykova, Plamena; Popova, Maria; Georgiev, Ivan

    2015-04-01

    Radiation risks may transcend national borders, and international cooperation serves to promote and enhance safety globally by exchanging experience and by improving capabilities to control hazards, to prevent accidents, to respond to emergencies and to mitigate any harmful consequences. International safety standards provide support for states in meeting their obligations under general principles of international law, such as those relating to environmental protection. Seismic safety is a key element of NPP safe operation. Safety and security measures have in common the aim of protecting human life and health and the environment. The Kozloduy NPP site is located in the stable part of the Moesian platform (area of about 50000 km2). From seismological point of view the Moesian platform is the most quite area on the territory of Bulgaria. There are neither historical nor instrumental earthquakes with M>4.5 occurred within the platform. The near region (area with radial extent of 30 km) of the NPP site is characterized with very low seismic activity. The strongest recorded quake is the 1987 earthquake МS=3.6, localized 22 km northwest of the Kozloduy NPP site on the territory of Romania. In line with international practice, the geological, geophysical and seismological characteristics of the region around the site have been investigated for the purpose of evaluating the seismic hazards at the NPP site. A local network (LSN) of sensitive seismographs having a recording capability for micro-earthquakes have been installed around Kozloduy NPP and operated since 1997. The operation and data processing, data interpretation, and reporting of the local micro-earthquake network are linked to the national seismic network (NOTSSI). A real-time data transfer from stations to National Data Center (in Sofia) was implemented using the VPN and MAN networks of the Bulgarian Telecommunication. Real-time and interactive data processing are performed by the Seismic Network Data

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

    NASA Astrophysics Data System (ADS)

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Hen's egg as a source of valuable biologically active substances.

    PubMed

    Zdrojewicz, Zygmunt; Herman, Marta; Starostecka, Ewa

    2016-01-01

    The aim of this article is to show current knowledge concerning valuable substances biologically active present in hen eggs and underline important nutritive role of hen eggs. Hen egg is a good source of nutrients such as proteins, vitamins (A, B2, B6, B12, D, E, K), minerals and lipids. The significant part of lipids is a group of unsaturated phospholipids, which are components of cell membranes, act protectively on the cardiovascular system and contribute to a decrease of cholesterol level and blood pressure. Therefore, the consumption of unsaturated phospholipids is recommended especially in patients suffering from diseases of the cardiovascular system. Another important substance is egg cystatin, which has a wide spectrum of biological functions, for example the ability to stimulate cell growth, inhibit inflammatory processes and has antibacterial and antiviral properties. Other substance presented in the egg white which helps fight bacteria is lysozyme. It is used in medicine as an aid in antibiotic therapy and analgesic in the course of infection, as well as in tumor malignancies. Among the components contained in the egg yolk there is also immunoglobulin Y which due to its therapeutic importance deserves special attention. Its use offers the possibility of replacing chemotherapeutic agents in the treatment of bacterial infections of digestive system, as well as an opportunity for the development of medicine associated with passive immunization of patients. The egg is a rich source of retinol which gradual depletion in the organism causes many eye pathologies. A very important and useful part of the egg, used in medicine is a shell and its membranes, due to the high collagen content relevant in the treatment of connective tissue diseases. PMID:27383572

  11. The IRIS Model: Building the Infrastructure for Seismology

    NASA Astrophysics Data System (ADS)

    Benson, R. B.; Ahern, T. K.

    2003-12-01

    The IRIS Consortium began a global, cooperative development in the mid-1980's, with the goal of being able to provide the necessary infrastructure (system) that would bring expensive, globally distributed geophysical data into the arena of open access, and to make these data available through a streamlined system of accessing that has profoundly improved the science of seismology. Historically, geophysical data were generated by scientists studying a particular problem, were limited in both the spatial and the temporal scales, and were self-managed and in native formats that hindered exchange. Data had little chance of being used again. The IRIS Data Management Center, located in Seattle, WA and affiliated with the University of Washington, operates an NSF-funded facility that is charged with acquiring, archiving, and distributing over 30 years (and counting) of geophysical time series data. Even though this volume exceeds 50 terabytes of dual-sorted data, these data can be requested on any spatial or temporal time scale. If you are studying the movement of mantle convection cells over decadal time scales, or studying aftershocks of a local earthquake, you can access these data from your workstation, convert these into your analysis format, and begin the process of doing hard science without ever having to burden yourself with acquiring the data, or drafting a detailed proposal justifying your area of interest. You can proceed directly to doing science. In the last two years, the IRIS DMC has targeted the problem of handling real time data generated in the field, forwarding it to a unified disk buffer, thereby eliminating all heterogeneity, and providing open access to large volumes of data which can be immediately utilized, providing the back-end for decision making in human time scales, not scientific time scales. We have now pushed this to the final step, closing the data loop and providing robust utilities that enable information-to-application functionality

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

    NASA Astrophysics Data System (ADS)

    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

  13. Geological and seismological survey for new design-basis earthquake ground motion of Kashiwazaki-Kariwa NPS

    NASA Astrophysics Data System (ADS)

    Takao, M.; Mizutani, H.

    2009-05-01

    viewpoint of geological structure, however we have decided to take into consideration simultaneous movement of the three faults which is 91km long in seismic design as a case of uncertainty. In the sea area, we conducted seismic reflection prospecting with sonic wave in the area stretching for about 140km along the coastline and 50km in the direction of perpendicular to the coastline. When we analyze the seismic profiles, we evaluated the activities of faults and foldings carefully on the basis of the way of thinking of 'fault-related-fault' because the sedimentary layers in the offing of Niigata prefecture are very thick and the geological structures are characterized by foldings. As a result of the seismic reflection survey and analyses, we assess that five active faults (foldings) to be taken into consideration to seismic design in the sea area and we evaluated that the F-B fault of 36km will have the largest impact on the KKNPS. [Seismological survey] As a result of analyses of the geological survey, data from NCOE and data from 2004 Chuetsu Earthquake, it became clear that there are factors that intensifies seismic motions in this area. For each of the two selected earthquake sources, namely NPWBFZ and F-B fault, we calculated seismic ground motions on the free surface of the base stratum as the design-basis ground motion (DBGM) Ss, using both empirical and numerical ground motion evaluation method. PGA value of DBGM is 2,300Gal for unit 1 to 4 located in the southern part of the KKNPS and 1,050Gal for unit 5 to 7 in the northern part of the site.

  14. Advanced Light Source activity report 1996/97

    SciTech Connect

    1997-09-01

    Ten years ago, the Advanced Light Source (ALS) existed as a set of drawings, calculations, and ideas. Four years ago, it stored an electron beam for the first time. Today, the ALS has moved from those ideas and beginnings to a robust, third-generation synchrotron user facility, with eighteen beam lines in use, many more in planning or construction phases, and hundreds of users from around the world. Progress from concepts to realities is continuous as the scientific program, already strong in many diverse areas, moves in new directions to meet the needs of researchers into the next century. ALS staff members who develop and maintain the infrastructure for this research are similarly unwilling to rest on their laurels. As a result, the quality of the photon beams the authors deliver, as well as the support they provide to users, continues to improve. The ALS Activity Report is designed to share the results of these efforts in an accessible form for a broad audience. The Scientific Program section, while not comprehensive, shares the breadth, variety, and interest of recent research at the ALS. (The Compendium of User Abstracts and Technical Reports provides a more comprehensive and more technical view.) The Facility Report highlights progress in operations, ongoing accelerator research and development, and beamline instrumentation efforts. Although these Activity Report sections are separate, in practice the achievements of staff and users at the ALS are inseparable. User-staff collaboration is essential as they strive to meet the needs of the user community and to continue the ALS's success as a premier research facility.

  15. Lunar seismology - The internal structure of the moon

    NASA Technical Reports Server (NTRS)

    Goins, N. R.; Dainty, A. M.; Toksoz, M. N.

    1981-01-01

    It is pointed out that seismology has provided the most detailed information concerning the structure and state of the earth's interior. Beginning in 1969, seismometers were landed on the moon by the Apollo missions, providing the first opportunity to attempt similar studies on another planetary body. In September 1977 the operation of these instruments was terminated. A description is presented of the internal structure of the moon, as determined from the obtained lunar seismic data. The analysis of the lunar data is approached in a systematic fashion, using appropriate techniques to minimize the number of necessary assumptions, extract the maximum amount of structural information, and determine its reliability. The completed lunar seismic network consists of four stations located at the landing sites of Apollo missions 12, 14, 15, and 16. Attention is given to crustal structure, the structure of the lunar mantle, the attenuating region, and the core.

  16. Lunar seismology - The internal structure of the moon

    NASA Astrophysics Data System (ADS)

    Goins, N. R.; Dainty, A. M.; Toksoz, M. N.

    1981-06-01

    It is pointed out that seismology has provided the most detailed information concerning the structure and state of the earth's interior. Beginning in 1969, seismometers were landed on the moon by the Apollo missions, providing the first opportunity to attempt similar studies on another planetary body. In September 1977 the operation of these instruments was terminated. A description is presented of the internal structure of the moon, as determined from the obtained lunar seismic data. The analysis of the lunar data is approached in a systematic fashion, using appropriate techniques to minimize the number of necessary assumptions, extract the maximum amount of structural information, and determine its reliability. The completed lunar seismic network consists of four stations located at the landing sites of Apollo missions 12, 14, 15, and 16. Attention is given to crustal structure, the structure of the lunar mantle, the attenuating region, and the core.

  17. Can mobile phones used in strong motion seismology?

    NASA Astrophysics Data System (ADS)

    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

  18. Seismology in South America; an interview with Alberto Giesecke

    USGS Publications Warehouse

    Spall, H.

    1980-01-01

    Dr. Alberto A. Giesecke is head of the Instituto Geofisico del Peru, in Lima, Peru, and Director of Centro Regional de Sismologia para America del Sur (CERESIS). The center is dedicated to the coordination and promotion of earthquake hazard mitigation. Dr. Giesecke was President of the National Research Council of Peru and currently is a member of the Board of Directors of the National Institute for Industrial Technological Research and Standards and of the National Institute for Research and Training in Telecommunications. He presided over the Organizing Committee for the General Assemblies of the International Association for Seismology and Physics of the Earth's interor and the International Union for Radio Science held in Lima, Peru, in 1973 and 1975, respectively. 

  19. SEISMOLOGY OF TRANSVERSELY OSCILLATING CORONAL LOOPS WITH SIPHON FLOWS

    SciTech Connect

    Terradas, J.; Arregui, I.; Verth, G.; Goossens, M.

    2011-03-10

    There are ubiquitous flows observed in the solar atmosphere of sub-Alfvenic speeds; however, after flaring and coronal mass ejection events flows can become Alfvenic. In this Letter, we derive an expression for the standing kink mode frequency due to siphon flow in coronal loops, valid for both low and high speed regimes. It is found that siphon flow introduces a linear, spatially dependent phase shift along coronal loops and asymmetric eigenfunctions. We demonstrate how this theory can be used to determine the kink and flow speed of oscillating coronal loops with reference to an observational case study. It is shown that the presence of siphon flow can cause the underestimation of magnetic field strength in coronal loops using the traditional seismological methods.

  20. Linking petrology and seismology of the southwest Greenland lithosphere

    NASA Astrophysics Data System (ADS)

    Lesher, C. E.; Vestergaard, C.; Brown, E.; Schutt, D.

    2015-12-01

    Mantle xenoliths from late-Proterozoic diamond-bearing kimberlitic dikes in the Kangerlussuaq, Sarfartoq and Maniitsoq areas of southwestern Greenland provide constraints on the composition and thermal state of lithospheric mantle beneath Greenland to depths of ~200 km [1]. Similarly, surface wave tomography studies carried out as part of the GLATIS project use a range of Rayleigh wave periods sensitive to structures at a similar depth interval within southwestern Greenland lithospheric mantle [2]. Here we link petrologic and seismologic constraints on the mantle lithosphere beneath Greenland utilizing methods of [3] that show that inferred chemical and mineralogical stratification inferred from petrology, showing mantle peridotite transitioning from garnet-free harzburgite to garnet lherzolite between ~70 and 180 km, cannot readily be resolved with fundamental mode Rayleigh waves. On the other hand, comparing phase velocities predicted from xenolith compositions, mineralogy and last equilibration temperatures and pressures, defining the continental geotherm during late-Proterozoic time, with those for the present-day mantle lithosphere suggest significant cooling of the cratonic mantle to a modern geotherm characterized by a heat flux of 30 mW/m2 and average crustal heat production of 0.3 mW/m3 [4]. These preliminary findings point to the weak dependence of shear wave velocities on mantle peridotite composition and mineralogy, and further illustrate its strong temperature dependence. Comparison of ancient and modern continental geotherms made possible by combining petrologic and seismological data, as shown here for southwest Greenland, provide additional constraints on secular cooling of cratonic regions linked to large-scale tectonic processes. [1] Bizzarro et al., 2003, CMP, 146; Sand et al., Lithos, 112. [2] Darbyshire et al., 2004, GJI, 158. [3] Schutt and Lesher, 2006, JGR, 111. [4] Meirerbachtol et al., 2015, JGR/ES, 120.

  1. Academia vs Industry: vanishing boundaries between global earthquake seismology and exploration seismics.

    NASA Astrophysics Data System (ADS)

    van der Hilst, R. D.

    2011-12-01

    Global seismology and exploration seismics have long lived in parallel universes, with little cross-fertilization of methodologies and with interaction between the associated communities often limited to company recruitment of students. Fortunately, this traditional separation of technology and people has begun to disappear. This is driven not only by continuing demands for human and financial resources (for companies and academia, respectively) but increasingly also by overlapping intellectual interest. First, 'waves are waves' (that is, the fundamental physics - and math to describe/handle it - is scale invariant) and many artificial boundaries are being removed by use of better wave theory, faster computers, and new data acquisition paradigms. For example, the development of dense sensor arrays (in USA, Europe, Asia - mostly China and Japan) is increasing the attraction (and need) of industry-style interrogation of massive data sets. Examples include large scale seismic exploration of Earth's deep interior with inverse scattering of teleseismic wavefields (e.g., Van der Hilst et al., Science, 2007). On the other hand, reservoir exploration and production benefits from expertise in earthquake seismology, both for better characterization of reservoirs and their overburden and for (induced) micro-earthquake analysis. Passive source methods (including but not restricted to ambient noise tomography) are providing new, economic opportunities for velocity analysis and monitoring, and studies of (micro)seismicity (e.g., source location, parameters, and moment tensor) allow in situ stress determination, tomographic velocity analysis with natural sources in the reservoir, and 4D monitoring (e.g., for hydrocarbon production, carbon sequestration, enhanced geothermal systems, and unconventional gas production). Second, the gap between the frequency ranges traditionally considered by both communities is being bridged by better theory, new sensor technology, and through

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

    NASA Astrophysics Data System (ADS)

    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.

  3. Toward a service-oriented e-infrastructure for data mining and data-intensive modeling applications in seismology: the VERCE (Virtual Earthquake and Seismology Research Community in Europe) initiative.

    NASA Astrophysics Data System (ADS)

    Vilotte, Jean-Pierre; van Hemert, Jano

    2010-05-01

    Global and regional seismology monitoring systems are continuously operated and are transmitting a growing wealth of seismological data in Europe and from around the world. This opens exciting opportunities for a large range of geophysical research. The multi-use nature of these data puts a great premium on open-access data archive infrastructures that are well integrated in the European Plate Observing System (EPOS)—an ESFRI initiative of the solid earth community. To exploit the full potential of this cornucopia of data and to guarantee optimal operation and design of the high-cost monitoring facilities, we need to new methods for data visualisation, data analysis and data modelling (imaging/inversion). Recent breakthroughs in theory and data analysis allow every byte of continuous seismological records to be used, extracting for example coherent information contained in background seismic "noise". This enables entirely new and exciting approaches for the imaging of wave sources and structures, the investigations of environmental changes, and the monitoring of volcanic and earthquake hazards. Data integration and data analysis applications are rapidly increasing in scale and complexity. Enabling advanced data analysis of these data within a well-designed data-aware distributed computing environment is becoming instrumental. Based on a set of data analysis and data modelling application requirements, the VERCE strategy will be presented here. The strategy of VERCE is to provide a comprehensive architecture and framework adapted to the scale and the diversity of these applications. It aims to integrate the community data infrastructure with Grid and HPC infrastructures. The first novel aspect of VERCE is a service-oriented architecture that provides well-equipped workbenches with an efficient communication layer between data and Grid infrastructures, which is augmented with bridges to European HPC facilities. The second novel aspect is the coupling between Grid

  4. Specification of High Activity Gamma-Ray Sources.

    ERIC Educational Resources Information Center

    International Commission on Radiation Units and Measurements, Washington, DC.

    The report is concerned with making recommendations for the specifications of gamma ray sources, which relate to the quantity of radioactive material and the radiation emitted. Primary consideration is given to sources in teletherapy and to a lesser extent those used in industrial radiography and in irradiation units used in industry and research.…

  5. Active radiometric calorimeter for absolute calibration of radioactive sources

    NASA Astrophysics Data System (ADS)

    Stump, K. E.; DeWerd, L. A.; Rudman, D. A.; Schima, S. A.

    2005-03-01

    This report describes the design and initial noise floor measurements of a radiometric calorimeter designed to measure therapeutic medical radioactive sources. The instrument demonstrates a noise floor of approximately 2 nW. This low noise floor is achieved by using high temperature superconducting (HTS) transition edge sensor (TES) thermometers in a temperature-control feedback loop. This feedback loop will be used to provide absolute source calibrations based upon the electrical substitution method. Other unique features of the calorimeter are (a) its ability to change sources for calibration without disrupting the vacuum of the instrument, and (b) the ability to measure the emitted power of a source in addition to the total contained source power.

  6. A seismologically consistent expression for the total area and volume of earthquake-triggered landsliding

    NASA Astrophysics Data System (ADS)

    Marc, Odin; Hovius, Niels; Meunier, Patrick; Gorum, Tolga; Uchida, Taro

    2016-04-01

    We present a new, seismologically consistent expression for the total area and volume of populations of earthquake-triggered landslides. This model builds on a set of scaling relationships between key parameters, such as landslide spatial density, seismic ground acceleration, fault length, earthquake source depth, and seismic moment. To assess the model we have assembled and normalized a catalog of landslide inventories for 40 shallow, continental earthquakes. Low landscape steepness causes systematic overprediction of the total area and volume of landslides. When this effect is accounted for, the model predicts the total landslide volume of 63% of 40 cases to within a factor 2 of the volume estimated from observations (R2=0.76). The prediction of total landslide area is also sensitive to the landscape steepness, but less so than the total volume, and it appears to be sensitive to controls on the landslide size-frequency distribution, and possibly the shaking duration. Some outliers are likely associated with exceptionally strong rock mass in the epicentral area, while others may be related to seismic source complexities ignored by the model. However, the close match between prediction and estimate for about two thirds of cases in our database suggests that rock mass strength is similar in many cases and that our simple seismic model is often adequate, despite the variety of lithologies and tectonic settings covered. This makes our expression suitable for integration into landscape evolution models and application to the anticipation or rapid assessment of secondary hazards associated with earthquakes.

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  9. ObsPy: A Python toolbox for Seismology, a Data Center Perspective

    NASA Astrophysics Data System (ADS)

    Beyreuther, Moritz; Barsch, Robert; Krischer, Lion; Megies, Tobias; Behr, Yannik; Wassermann, Joachim

    2010-05-01

    ObsPy: A Python toolbox for seismology (http://www.obspy.org) aims at filling the gap between interactive analysis and automatic data acquistion systems. Automatic batch analysis of continuous data streams or feeding a so far unknown formatted data stream into an acquistion system are two possible applications. Python provides a platform independent, free and open source interpreter language including a large collection of scientific open-source modules thus allowing rapid development of prototype code. ObsPy extends Python by providing the seismologist with basic seismological routines, e.g. MiniSEED, SAC, GSE2 read and write support, various pickers, filters, instrument correction... The data itself is stored in numpy.ndarrays allowing powerful numerical array-programming modules like NumPy (http://numpy.scipy.org) or SciPy (http://scipy.org) to be used. Also SeisComP3 has a Python API which makes use of the previous mentioned modules, thus making it easy to extend SeisComP3 with the help of the ObsPy library. Especially for data centers the ObsPy ArcLink and XSEED modules are of special interest. The ArcLink module makes it possible to easily automatically access the data via ArcLink or for testing the servers functionality. The XSEED module allows to convert data from dataless SEED to XML-SEED and back. The XML-SEED format is very verbose and easy extensible for internal purposes. For "public" distribution the resulting extended XML-SEED can always be converted back to the standard exchange format dataless SEED (loosing the additionally fields). An application of ObsPy is running on the Azores. Here, seismic data are continuous recorded with National Instruments digitizers which are writing data in an binary format every 10s. ObsPy is used to feed the data in EarthWorm and SeisComP3 by decoding the binary format every 30s and appending the new data to a MiniSEED file. The MiniSEED file is continuously scanned by the mseed_scan module of the seedlink server and

  10. Source-based neurofeedback methods using EEG recordings: training altered brain activity in a functional brain source derived from blind source separation

    PubMed Central

    White, David J.; Congedo, Marco; Ciorciari, Joseph

    2014-01-01

    A developing literature explores the use of neurofeedback in the treatment of a range of clinical conditions, particularly ADHD and epilepsy, whilst neurofeedback also provides an experimental tool for studying the functional significance of endogenous brain activity. A critical component of any neurofeedback method is the underlying physiological signal which forms the basis for the feedback. While the past decade has seen the emergence of fMRI-based protocols training spatially confined BOLD activity, traditional neurofeedback has utilized a small number of electrode sites on the scalp. As scalp EEG at a given electrode site reflects a linear mixture of activity from multiple brain sources and artifacts, efforts to successfully acquire some level of control over the signal may be confounded by these extraneous sources. Further, in the event of successful training, these traditional neurofeedback methods are likely influencing multiple brain regions and processes. The present work describes the use of source-based signal processing methods in EEG neurofeedback. The feasibility and potential utility of such methods were explored in an experiment training increased theta oscillatory activity in a source derived from Blind Source Separation (BSS) of EEG data obtained during completion of a complex cognitive task (spatial navigation). Learned increases in theta activity were observed in two of the four participants to complete 20 sessions of neurofeedback targeting this individually defined functional brain source. Source-based EEG neurofeedback methods using BSS may offer important advantages over traditional neurofeedback, by targeting the desired physiological signal in a more functionally and spatially specific manner. Having provided preliminary evidence of the feasibility of these methods, future work may study a range of clinically and experimentally relevant brain processes where individual brain sources may be targeted by source-based EEG neurofeedback. PMID

  11. Volcanic eruption source parameters from active and passive microwave sensors

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario; Marzano, Frank S.; Cimini, Domenico; Mereu, Luigi

    2016-04-01

    It is well known, in the volcanology community, that precise information of the source parameters characterising an eruption are of predominant interest for the initialization of the Volcanic Transport and Dispersion Models (VTDM). Source parameters of main interest would be the top altitude of the volcanic plume, the flux of the mass ejected at the emission source, which is strictly related to the cloud top altitude, the distribution of volcanic mass concentration along the vertical column as well as the duration of the eruption and the erupted volume. Usually, the combination of a-posteriori field and numerical studies allow constraining the eruption source parameters for a given volcanic event thus making possible the forecast of ash dispersion and deposition from future volcanic eruptions. So far, remote sensors working at visible and infrared channels (cameras and radiometers) have been mainly used to detect, track and provide estimates of the concentration content and the prevailing size of the particles propagating within the ash clouds up to several thousand of kilometres far from the source as well as track back, a-posteriori, the accuracy of the VATDM outputs thus testing the initial choice made for the source parameters. Acoustic wave (infrasound) and microwave fixed scan radar (voldorad) were also used to infer source parameters. In this work we want to put our attention on the role of sensors operating at microwave wavelengths as complementary tools for the real time estimations of source parameters. Microwaves can benefit of the operability during night and day and a relatively negligible sensitivity to the presence of clouds (non precipitating weather clouds) at the cost of a limited coverage and larger spatial resolution when compared with infrared sensors. Thanks to the aforementioned advantages, the products from microwaves sensors are expected to be sensible mostly to the whole path traversed along the tephra cloud making microwaves particularly

  12. Inducing in situ, nonlinear soil response applying an active source

    USGS Publications Warehouse

    Johnson, P.A.; Bodin, P.; Gomberg, J.; Pearce, F.; Lawrence, Z.; Menq, F.-Y.

    2009-01-01

    [1] It is well known that soil sites have a profound effect on ground motion during large earthquakes. The complex structure of soil deposits and the highly nonlinear constitutive behavior of soils largely control nonlinear site response at soil sites. Measurements of nonlinear soil response under natural conditions are critical to advancing our understanding of soil behavior during earthquakes. Many factors limit the use of earthquake observations to estimate nonlinear site response such that quantitative characterization of nonlinear behavior relies almost exclusively on laboratory experiments and modeling of wave propagation. Here we introduce a new method for in situ characterization of the nonlinear behavior of a natural soil formation using measurements obtained immediately adjacent to a large vibrator source. To our knowledge, we are the first group to propose and test such an approach. Employing a large, surface vibrator as a source, we measure the nonlinear behavior of the soil by incrementally increasing the source amplitude over a range of frequencies and monitoring changes in the output spectra. We apply a homodyne algorithm for measuring spectral amplitudes, which provides robust signal-to-noise ratios at the frequencies of interest. Spectral ratios are computed between the receivers and the source as well as receiver pairs located in an array adjacent to the source, providing the means to separate source and near-source nonlinearity from pervasive nonlinearity in the soil column. We find clear evidence of nonlinearity in significant decreases in the frequency of peak spectral ratios, corresponding to material softening with amplitude, observed across the array as the source amplitude is increased. The observed peak shifts are consistent with laboratory measurements of soil nonlinearity. Our results provide constraints for future numerical modeling studies of strong ground motion during earthquakes.

  13. Rheological implications of the seismological lithosphere-asthenosphere boundary

    NASA Astrophysics Data System (ADS)

    Fischer, K. M.; Ford, H. A.; Lekic, V.; Hirth, G.

    2012-12-01

    Evidence from scattered and reflected seismic waves indicates that the transition between the seismologically-defined lithosphere and asthenosphere is relatively rapid in depth in many tectonic settings with the exception of cratons. For example, in non-cratonic regions of Australia and North America Sp receiver functions typically image a downward deccrease in shear-wave velocity whose depth ranges from ~50 to 130 km. Modeling of these Sp phases with synthetic receiver functions indicates significant (4-10%) shear velocity drops over depth ranges of ~30 km or less. Because these Sp phases originate at depths within the transition from high velocity mantle lid to low velocity zone in surface wave tomography models, and because the Sp phases account for most or all of the lid to low velocity zone contrast, they are interpretable as the seismological lithosphere-asthenosphere boundary. Thermal gradients in a wide range of geodynamical models for comparable tectonic environments are typically distributed over much larger depth ranges. The Sp phases are thus difficult to reconcile with an LAB that is governed solely by temperature. Rather, they suggest the presence of other factors that weaken the top of the asthenosphere, for example small amounts of partial melt (0.5-1.5%) or greater volatile content. Beneath cratons, a drop in shear velocity and rotation of azimuthal anisotropy at the base of the lithosphere in surface wave tomography argue for widespread sub-cratonic asthenosphere. However, Sp imaging that we conducted in cratonic regions of Australia and North America did not find coherent converted phases at potential LAB depths, arguing for LAB velocity gradients that are distributed over more than ~60 km in depth. Such gradual velocity gradients are consistent with a purely thermal origin, although slow vertical increases in melt or volatile content cannot be ruled out. To more directly assess the rheological implications of the seismological LAB, we estimated

  14. Moving towards persistent identification in the seismological community

    NASA Astrophysics Data System (ADS)

    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

  15. Retrospective Seismological Observations: Recording yesterday's earthquakes on seismometers installed today

    NASA Astrophysics Data System (ADS)

    Entwistle, E.; Curtis, A.; Baptie, B.; Meles, G. A.

    2013-12-01

    Earthquake seismograms are usually available only at seismometers that are active at the time of the event. However, recently Source-Receiver Interferometry (SRI) was shown to combine spatial and temporal redatuming to construct seismograms on seismometers deployed only before, during or after the earthquake occurred. Thus seismometers can be redeployed post-earthquake in more useful locations, and earthquake seismograms can nevertheless be obtained (Curtis et al., 2012). We identify suitable SRI source and receiver geometries to construct new earthquake seismograms across the USA. Suitable geometries satisfy: 1) minimum and maximum source-to-receiver distances, 2) a source-to-receiver-array ray path that intersects one or more other seismometers, 3) a dense receiver array that lies approximately perpendicularly (70 - 110 degrees) to a point on that ray, 4) sufficiently long ambient noise records. We also improve SRI receiver integration by embedding seismometer arrays within 2D spatial Voronoi cells. Using data from the USArray TA network we successfully reconstructed M5.5 earthquake seismograms at seven virtual locations in New Mexico. Thus, a new database of retrospective earthquake seismograms can be constructed across the USA.

  16. Calorimetric method for determination of {sup 51}Cr neutrino source activity

    SciTech Connect

    Veretenkin, E. P. Gavrin, V. N.; Danshin, S. N.; Ibragimova, T. V.; Kozlova, Yu. P.; Mirmov, I. N.

    2015-12-15

    Experimental study of nonstandard neutrino properties using high-intensity artificial neutrino sources requires the activity of the sources to be determined with high accuracy. In the BEST project, a calorimetric system for measurement of the activity of high-intensity (a few MCi) neutrino sources based on {sup 51}Cr with an accuracy of 0.5–1% is created. In the paper, the main factors affecting the accuracy of determining the neutrino source activity are discussed. The calorimetric system design and the calibration results using a thermal simulator of the source are presented.

  17. Coronal Seismology: Inferring Magnetic Fields and Exploring Damping Mechanisms

    NASA Astrophysics Data System (ADS)

    McAteer, R. T. James; Ireland, Jack

    2015-08-01

    Recent observations in extreme ultra-violet wavelengths have shown that the solar corona oscillates at many different spatial sizes and temporal size scales. However, much remains unknown about many of these oscillations; they are intermittent for unknown reasons, appear on some coronal features and not on other, similar, neighboring features, and may (or may not) be magnetohydrodynamic (MHD) wave modes. Definitive causes of the structure and origins of these oscillations are still largely lacking. Here, we use automated oscillation detection routines to study a large sample of oscillations, inferring physical mechanisms as to how and why the corona varies.First, we measure the oscillation content of different physical regions on the Sun in SDO AIA data, using two different automated oscillation detection algorithms. This shows a power-law distribution in oscillatory frequency, disagreeing with strong historical assumptions about the nature of coronal heating and coronal seismology. We show how such disagreements can be reconciled by using a power-law background for oscillatory signals.Second we use coronal seismology to provide a means to infer coronal plasma parameters and to differentiate between potential damping mechanisms. Recent sets of kink-mode observations (usually 5-8 loops) have come insights into how the coronal is structured and how it evolves. We present a complex set of flare-induced, off-limb, coronal kink-mode oscillations of almost 100 loops. These display a spread of periods, amplitudes, and damping times, allowing us to probe the spatial distribution of these parameters for the first time. Both Fourier and Wavelet routines are used to automatically extract and characterize these oscillations. An initial period of P~500s, results in an inferred coronal magnetic field of B~20G. The decrease in the oscillation period of the loop position corresponds to a drop in number density inside the coronal loop, as predicted by MHD. As the the period drops

  18. IRIS - A Community-Based Facility to Support Research in Seismology

    NASA Astrophysics Data System (ADS)

    Ingate, S.; Ahern, T.; Butler, R.; Fowler, J.; Simpson, D.; Taber, J.; van der Vink, G.

    2002-12-01

    programs. In the 18 years since the founding of IRIS, the core programs have grown to meet most of the original design goals and the Consortium continues to evolve in response to the community's changing needs. The GSN has now 126 permanent seismic stations distributed throughout the world with real-time connectivity to nearly 90 sites and dial-up links to most others. In addition to seismometers, microbarographs are installed at 19 sites and GPS instrumentation is located at 16 sites. The PASSCAL program supports between 50 and 60 experiments per year, from a lending pool of 250 broadband seismic sensor systems, and over 800 higher frequency systems for active source experiments. All seismic data acquired under the GSN and PASSCAL programs are made openly and freely available to anyone on the Internet, through the DMS. The DMS currently receives over 6Tb per year, and is able to service most requests for data within hours. Shipments in 2002 serviced nearly 60,000 requests, comprising nearly 1Tb of data, made to 563 different seismologists from 145 institutions in 33 countries around the world. The E&O program is relatively young, yet is making considerable inroads through its museum partnership (reaching 8,000,000 people per year); distribution of inexpensive seismographs; development of teaching modules and other educational materials for schools; technical support to internet-enabled school-based networks; workshops for geoscience educators; and undergraduate summer internships.

  19. Information-Driven Active Audio-Visual Source Localization.

    PubMed

    Schult, Niclas; Reineking, Thomas; Kluss, Thorsten; Zetzsche, Christoph

    2015-01-01

    We present a system for sensorimotor audio-visual source localization on a mobile robot. We utilize a particle filter for the combination of audio-visual information and for the temporal integration of consecutive measurements. Although the system only measures the current direction of the source, the position of the source can be estimated because the robot is able to move and can therefore obtain measurements from different directions. These actions by the robot successively reduce uncertainty about the source's position. An information gain mechanism is used for selecting the most informative actions in order to minimize the number of actions required to achieve accurate and precise position estimates in azimuth and distance. We show that this mechanism is an efficient solution to the action selection problem for source localization, and that it is able to produce precise position estimates despite simplified unisensory preprocessing. Because of the robot's mobility, this approach is suitable for use in complex and cluttered environments. We present qualitative and quantitative results of the system's performance and discuss possible areas of application. PMID:26327619

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

    NASA Astrophysics Data System (ADS)

    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

  1. Development of a novel electron source for active space experiments

    NASA Astrophysics Data System (ADS)

    Everding, Daniel

    2013-01-01

    Recent advances in light emitting diode (LED) technology have facilitated a potential remedy to the problems plaguing filament based electron sources. Using spaceworthy LEDs, the photoelectron cathode and its progenitor the ultraviolet cathode (UVC) take advantage of the photoelectric effect to produce electrons for space based experiments. To produce these devices, two species of LED, each producing either ultraviolet or visible radiation, were collected and tested to determine potential photocurrent output. Additionally, materials with requisite photoemission characteristics were collected and tested in vacuum with the LEDs to assess their usefulness as photoelectron sources. Furthermore, circuitry and computer software was compiled, tested, and refined to control the experimental and custodial duties of the UVC and photoelectron cathode while deployed as an electron source in space.

  2. U.S.-Soviet seismology research funds switched to air force

    NASA Astrophysics Data System (ADS)

    Simarski, Lynn Teo

    Department of Defense funding for seismology research has seen some changes in both amount and administration. While Congress increased the budget of the Defense Advanced Research Projects Agency (DARPA) by almost $1.4 billion this year, about 13% over last year (as reported October 30 in the Washington Post), it also rescinded DARPA's authority to manage funding of the Soviet Union program of the Incorporated Research Institutions for Seismology (IRIS).

  3. The role of the Organization of American States in the development of seismology in Latin America

    USGS Publications Warehouse

    Quesada, A.

    1982-01-01

    Seismological studies in Latin America were initiated at the beginning of the 20th century, when the first seismological stations were deployed by certain scientific associations. These efforts provided an incentive to the professional community for further activites. Until this date, the only seismic records that existed were historical accounts of catastrophes caused by earthquakes and volcanic eruptions. This type of information of course, leads to "fantasy" and incorrect descriptions of what has taken place. 

  4. A portable active interrogation system using a switchable AmBe neutron source

    NASA Astrophysics Data System (ADS)

    Allen, Matthew; Hertz, Kristin; Kunz, Christopher; Mascarenhas, Nicholas

    2005-09-01

    Active neutron interrogation is an effective technique used to locate fissionable material. This paper discusses a portable system that utilizes a AmBe neutron source. The AmBe source consists of an americium alpha source and a beryllium target that can be switched into alignment to turn the source on and out of alignment to turn the source off. This offers a battery operated backpack portable source. The detector system that has been fabricated for use with this source is a fifteen tube 3He neutron detector. The results of initial experiments with the detector and MCNP calculations are discussed.

  5. Seismology on a Comet: Calibration Measurements, Modeling and Inversion

    NASA Astrophysics Data System (ADS)

    Faber, C.; Hoppe, J.; Knapmeyer, M.; Fischer, H.; Seidensticker, K. J.

    2011-12-01

    The Mission Rosetta was launched to comet 67P/Churyumov-Gerasimenko in 2004. It will finally reach the comet and will deliver the Lander Philae at the surface of the nucleus in November 2014. The Lander carries ten experiments, one of which is the Surface Electric Sounding and Acoustic Monitoring Experiment (SESAME). Part of this experiment is the Comet Acoustic Surface Sounding Experiment (CASSE) housed in the three feet of the lander. The primary goal of CASSE is to determine the elastic parameters of the surface material, like the Young's modulus and the Poisson ratio. Additional goals are the determination of shallow structure, quantification of porosity, and the location of activity spots and thermally and impact caused cometary activity. We conduct calibration measurements with accelerometers identical to the flight model. The goal of these measurements is to develop inversion procedures for travel times and to estimate the expected accuracy that CASSE can achieve in terms of elastic wave velocity, elastic parameters, and source location. The experiments are conducted mainly on sandy soil, in dry, wet or frozen conditions, and apart from buildings with their reflecting walls and artificial noise sources. We expect that natural sources, like thermal cracking at sunrise and sunset, can be located to an accuracy of about 10 degrees in direction and a few decimeters (1σ) in distance if occurring within the sensor triangle and from first arrivals alone. The accuracy of the direction is essentially independent of the distance, whereas distance determination depends critically on the identification of later arrivals. Determination of elastic wave velocities on the comet will be conducted with controlled sources at known positions and are likely to achieve an accuracy of σ=15% for the velocity of the first arriving wave. Limitations are due to the fixed source-receiver geometry and the wavelength emitted by the CASSE piezo-ceramic sources. In addition to the

  6. Issues in Humanoid Audition and Sound Source Localization by Active Audition

    NASA Astrophysics Data System (ADS)

    Nakadai, Kazuhiro; Okuno, Hiroshi G.; Kitano, Hiroaki

    In this paper, we present an active audition system which is implemented on the humanoid robot "SIG the humanoid". The audition system for highly intelligent humanoids localizes sound sources and recognizes auditory events in the auditory scene. Active audition reported in this paper enables SIG to track sources by integrating audition, vision, and motor movements. Given the multiple sound sources in the auditory scene, SIG actively moves its head to improve localization by aligning microphones orthogonal to the sound source and by capturing the possible sound sources by vision. However, such an active head movement inevitably creates motor noises.The system adaptively cancels motor noises using motor control signals and the cover acoustics. The experimental result demonstrates that active audition by integration of audition, vision, and motor control attains sound source tracking in variety of conditions.onditions.

  7. Real-time GNSS seismology using a single receiver

    NASA Astrophysics Data System (ADS)

    Li, Xingxing; Guo, Bofeng; Lu, Cuixian; Ge, Maorong; Wickert, Jens; Schuh, Harald

    2014-07-01

    High-rate GNSS has attracted increasing attention and numerous applications in geohazard monitoring and early warning. In this paper, we investigate three current existing single-receiver approaches for real-time GNSS seismology, comparing their observation models for equivalence and assessing the impact of main error components. We propose some refinements to the variometric approach and especially consider compensating the geometry error component by using the accurate initial coordinates before the earthquake to eliminate the drift trend in the integrated coseismic displacements. After careful corrections of satellite ephemeris, ionospheric delay, tropospheric delay and geometry errors, the refined variometric approach and the temporal point positioning (TPP) method have equivalent mathematical model with the converged precise point positioning (PPP). We evaluated the precision of the variometric and TPP approaches with various error correction schemes and duration time using numerous data sets and demonstrated that few centimetres accuracy of coseismic displacements is achievable even for 20 min interval. We applied these single-receiver approaches to process 1 Hz GPS data collected from the Tohoku-Oki earthquake (Mw 9.0, 2011 March 11) in Japan to capture coseismic displacement, and further, inverted the obtained displacement fields for fault slip distribution and moment magnitude. Comparisons of the results obtained using the refined variometric approach and TPP, as well as the converged PPP, displayed very good consistence both in coseismic displacements within few centimetres and in the slip distribution patterns and moment magnitudes.

  8. Identification of a potential monogenetic volcano using seismology

    NASA Astrophysics Data System (ADS)

    Legrand, Denis; Bataille, Klaus; Cembrano, Jose; Pavez, Andres; Bashkar, Kundu; Gahalaut, Vineet; Perez, Raul

    2014-05-01

    Some monogenetic volcano fields are very close to cities, such as in New Zealand or in México. A new monogenetic volcano may appear at any place and at any time, which could be potentially hazardous for nearby regions. The ability to detect a new one in advance is obviously very important and challenging. The existence of nearby seismometers may help for such detection. Magma sometimes reaches the surface with the birth of a volcano which can be monogenetic, but in other cases the magma does not reach the surface How to detect such movements? How to be sure the magma will reach the surface? Some observations may detect them, such as seismicity which is distributed as a swarm, with a very peculiar distribution in time and magnitudes. In particular, it is important to distinguish between a tectonic swarm and a volcanic swarm. Scaling laws of seismicity in magnitude and time help to perform such a distinction. We show three cases: a seismic swarm in Chile, in the 2007 Aysen crisis, corresponding to an aborted birth of a monogenetic volcano; a seismic swarm triggered after the 2004 great Mw~9.2 Sumatra-Andaman earthquake over an old monogenetic volcano; and a spatial study of monogenetic volcanoes in Mexico (Michoacán) showing the difficulty to forecast the place and time of the birth of a monogenetic cone without seismological records.

  9. The lithosphere in central Europe—seismological and petrological aspects

    NASA Astrophysics Data System (ADS)

    Babuška, V.; Plomerová, J.

    1992-06-01

    The lithosphere thickness in the Variscan belt of central Europe varies between about 60 and 150 km with typical values of 100-120 km. Our estimates, derived from directionally independent representative P-wave residuals, are in good agreement with magnetotelluric determinations of a layer with increased conductivity in the upper mantle. The large-scale anisotropies of the subcrustal lithosphere beneath four seismological stations determined from spatial variations of relative P residuals vary between 6.5 and 15.2% for P velocities; the S-wave anisotropies determined from SKS polarizations vary between 2.2 and 6.7%. These values are in reasonable agreement with the anisotropies of peridotites determined in laboratory. Systematic spatial variations of the directional terms of relative residuals in dependence on azimuths and incidence angles suggest the existence of large dipping anisotropic structures in the subcrustal lithosphere. The residual patterns at most stations in the Saxothuringicum, Rhenohercynicum and in the Massif Central imply northwesterly orientated dips of the anisotropic structures while stations in the Moldanubicum, the Alpine Foredeep and most of the Alps north of the Insubric line, suggest southeasterly orientated dips. In our interpretation the dipping anisotropic structures may represent paleosubductions which retain olivine preferred orientations originating from an ancient oceanic lithosphere. The Variscides of central Europe may thus represent a collision zone characterized by two systems of paleosubductions divergent relative to the suture between the Moldanubicum and the Saxothuringicum.

  10. Information-Driven Active Audio-Visual Source Localization

    PubMed Central

    Schult, Niclas; Reineking, Thomas; Kluss, Thorsten; Zetzsche, Christoph

    2015-01-01

    We present a system for sensorimotor audio-visual source localization on a mobile robot. We utilize a particle filter for the combination of audio-visual information and for the temporal integration of consecutive measurements. Although the system only measures the current direction of the source, the position of the source can be estimated because the robot is able to move and can therefore obtain measurements from different directions. These actions by the robot successively reduce uncertainty about the source’s position. An information gain mechanism is used for selecting the most informative actions in order to minimize the number of actions required to achieve accurate and precise position estimates in azimuth and distance. We show that this mechanism is an efficient solution to the action selection problem for source localization, and that it is able to produce precise position estimates despite simplified unisensory preprocessing. Because of the robot’s mobility, this approach is suitable for use in complex and cluttered environments. We present qualitative and quantitative results of the system’s performance and discuss possible areas of application. PMID:26327619

  11. Simulations as Active Assessment?: Typologizing by Purpose and Source

    ERIC Educational Resources Information Center

    Kollars, Nina A.; Rosen, Amanda M.

    2013-01-01

    Assessment through simulation is something that political science pedagogy has yet to explore in a robust manner. This article advances analysis of social science simulation and assessment by laying out a typology of active-learning activities that isolates and examines their potential for assessment. In short, we argue that there are essentially…

  12. Biochemical assays on plasminogen activators and hormones from kidney sources

    NASA Technical Reports Server (NTRS)

    Barlow, Grant H.; Lewis, Marian L.; Morrison, Dennis R.

    1988-01-01

    Investigations were established for the purpose of analyzing the conditioned media from human embryonic kidney cell subpopulations separated in space by electrophoresis. This data is based on the experiments performed on STS-8 on the continuous flow electrophoresis system. The primary biological activity that was analyzed was plasminogen activator activity, but some assays for erythropoeitin and human granulocyte colony stimulating activity were also performed. It is concluded that a battery of assays are required to completely define the plasminogen activator profile of a conditioned media from cell culture. Each type of assay measures different parts of the mixture and are influenced by different parameters. The functional role of each assay is given along with an indication of which combination of assays are required to answer specific questions. With this type of information it is possible by combinations of assays with mathematical analysis to pinpoint a specific component of the system.

  13. Long-term accumulation and improvements in seismic event data for the polar regions by the International Seismological Centre

    NASA Astrophysics Data System (ADS)

    Storchak, Dmitry A.; Kanao, Masaki; Delahaye, Emily; Harris, James

    2015-03-01

    The International Seismological Centre (ISC) is a non-governmental non-profit making organization funded by 62 research and operational institutions around the world and charged with the production of the ISC Bulletin - the definitive summary of the global seismicity based on reports from over 130 agencies worldwide, including those active in Polar regions. Jointly with the National Earthquake Information Center (NEIC) of the United States Geological Survey (USGS), the ISC runs the International Seismic Station Registry. The ISC is also charged with maintaining the International Association of Seismology and Physics of the Earth Interior (IASPEI) Reference event List. The new ISC product, the ISC Event Bibliography allows users to obtain references to scientific articles describing specific seismic events, natural and anthropogenic. In this paper we demonstrate how these products and services are applicable to seismic events both in Arctic and Antarctic regions. We also give a summary of the ISC data in polar regions and provide credit to Institutions that report these data to the ISC.

  14. Hanford Tank Waste - Near Source Treatment of Low Activity Waste

    SciTech Connect

    Ramsey, William Gene

    2013-08-15

    Abstract only. Treatment and disposition of Hanford Site waste as currently planned consists of 100+ waste retrievals, waste delivery through up to 8+ miles of dedicated, in-ground piping, centralized mixing and blending operations- all leading to pre-treatment combination and separation processes followed by vitrification at the Hanford Tank Waste Treatment and Immobilization Plant (WTP). The sequential nature of Tank Farm and WTP operations requires nominally 15-20 years of continuous operations before all waste can be retrieved from many Single Shell Tanks (SSTs). Also, the infrastructure necessary to mobilize and deliver the waste requires significant investment beyond that required for the WTP. Treating waste as closely as possible to individual tanks or groups- as allowed by the waste characteristics- is being investigated to determine the potential to 1) defer, reduce, and/or eliminate infrastructure requirements, and 2) significantly mitigate project risk by reducing the potential and impact of single point failures. The inventory of Hanford waste slated for processing and disposition as LAW is currently managed as high-level waste (HLW), i.e., the separation of fission products and other radionuclides has not commenced. A significant inventory of this waste (over 20M gallons) is in the form of precipitated saltcake maintained in single shell tanks, many of which are identified as potential leaking tanks. Retrieval and transport (as a liquid) must be staged within the waste feed delivery capability established by site infrastructure and WTP. Near Source treatment, if employed, would provide for the separation and stabilization processing necessary for waste located in remote farms (wherein most of the leaking tanks reside) significantly earlier than currently projected. Near Source treatment is intended to address the currently accepted site risk and also provides means to mitigate future issues likely to be faced over the coming decades. This paper

  15. Effect of sole nitrogen sources and temperature on activated sludge

    SciTech Connect

    Mines, R.O. Jr.; Sherrard, J.H.

    1999-07-01

    The effects of temperature on biokinetic coefficients used to design aerobic biological systems treating nitrogen deficient wastewaters at a COD: TKN ratio of 13.7:1 are presented. The impact of temperature on substrate removal, waste biosolids production, and oxygen requirements with the effects of nitrification is delineated at temperatures of 5 C, 10 C, 20 C, and 30 C for two nitrogen sources; ammonia and nitrate. Temperature correction coefficients ({theta}) are presented and the implications for the design and operation of suspended growth biological systems are discussed.

  16. How to Detect Amygdala Activity with Magnetoencephalography using Source Imaging

    PubMed Central

    Balderston, Nicholas L.; Schultz, Douglas H.; Baillet, Sylvain; Helmstetter, Fred J.

    2013-01-01

    In trace fear conditioning a conditional stimulus (CS) predicts the occurrence of the unconditional stimulus (UCS), which is presented after a brief stimulus free period (trace interval)1. Because the CS and UCS do not co-occur temporally, the subject must maintain a representation of that CS during the trace interval. In humans, this type of learning requires awareness of the stimulus contingencies in order to bridge the trace interval2-4. However when a face is used as a CS, subjects can implicitly learn to fear the face even in the absence of explicit awareness*. This suggests that there may be additional neural mechanisms capable of maintaining certain types of "biologically-relevant" stimuli during a brief trace interval. Given that the amygdala is involved in trace conditioning, and is sensitive to faces, it is possible that this structure can maintain a representation of a face CS during a brief trace interval. It is challenging to understand how the brain can associate an unperceived face with an aversive outcome, even though the two stimuli are separated in time. Furthermore investigations of this phenomenon are made difficult by two specific challenges. First, it is difficult to manipulate the subject's awareness of the visual stimuli. One common way to manipulate visual awareness is to use backward masking. In backward masking, a target stimulus is briefly presented (< 30 msec) and immediately followed by a presentation of an overlapping masking stimulus5. The presentation of the mask renders the target invisible6-8. Second, masking requires very rapid and precise timing making it difficult to investigate neural responses evoked by masked stimuli using many common approaches. Blood-oxygenation level dependent (BOLD) responses resolve at a timescale too slow for this type of methodology, and real time recording techniques like electroencephalography (EEG) and magnetoencephalography (MEG) have difficulties recovering signal from deep sources. However

  17. Seismic Software Evaluation at the Swiss Seismological Service

    NASA Astrophysics Data System (ADS)

    Clinton, John; Olivieri, Marco; Kaestli, Philipp

    2010-05-01

    The Swiss Seismological Service (SED) has an ongoing responsibility to improve the seismic monitoring capability for Switzerland. This is a crucial issue for a country with a low background seismicity but where a large M6+ earthquake is expected in the next decades. With over 30 stations and station spacing of ~25km, the SED operate one of the densest broadband networks in the world, which is complimented by a similar number of real time strong motion stations. An existing in-house processing software has been operational for the last 15 years, and though well suited for the Swiss setting, including the ability to 1. automatically locate and alert local events and 2. manually relocate events with a nonlinear location algorithm using a 3-D velocity model, the software does not satisfactorily accommodate integration of standard community software tools, nor provide a modern database interface for either station metadata or event parameters. To take advantage of major improvements in software architecture and community tools, we wish to migrate to a community standard solution for data acquisition, automatic and manual processing, and archival. We have been evaluating in detail SeisComp3, a state-of-the-art monitoring system developed by GFZ, as well as Nanometrics Apollo Suite (which uses USGS Hydra at it core for event processing). We present our analysis of the capabilities of each software we have been evaluating. In particular, we focus on the capability of each software to detect and identify small local (>Ml1) as well as large regional events. We discuss our results in terms or location and magnitude accuracy, with particular attention to the specific improvements needed from monitoring systems for improved monitoring of small regions with high quality seismic networks.

  18. Seismological modeling of the Delta Scuti star: CD-24 7599

    SciTech Connect

    Bradley, P.A.; Guzik, J.A.

    1996-11-01

    A major goal of asteroseismology is a better understanding of stellar evolution via ``snapshots`` of many stars of different masses in different evolutionary states. For stars of about 2M{sub {circle_dot}} near the sequence, b Scuti stars are the usual suspects. There is an ongoing renaissance in theoretical modeling of 6 Scuti stars brought on by improvements in constitutive physics and by a dramatic increase in the number of modes observed. FG Virginis and CD-24` 7599 are two of the best studied objects, and they have 19 and 13 known frequencies, respectively. . We create models using an updated and modified version of the Iben code described by Guzik & Cox that includes either of the two versions of the OPAL opacities . We use the star`s observed location on the H-R diagram as a starting point for our seismological modeling. Because there is no evidence for observed t = 3 modes, we only consider l = 0, 1, and 2 modes in our analysis. We take into account rotational splitting (about 5 - 10 {mu}Hz) in our frequency matching. Several observed modes must be rotationally split members of a given mode. CD-24` 7599 is less than halfway through core hydrogen burning, and the modes appear to be a set of consecutive 3rd through 5th overtones of {ital l} = 0 through 2 modes. With only 13 modes, we find satisfactory fits with models between 1.9 and 2.0 M{sub {circle_dot}} that fall within the observed luminosity and effective temperature range. By contrast, Guzik & Bradley suggest that FG Virginis is over halfway through core hydrogen burning and the best fitting models lie near 1.80 or 2.00 M{sub {circle_dot}}. We see persistent discrepancies in some low frequency modes, which suggests we may need a small amount of core overshoot or a slight change in metallicity to duplicate FG Virginis.

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

    NASA Astrophysics Data System (ADS)

    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.

  20. SEISMOLOGY OF STANDING KINK OSCILLATIONS OF SOLAR PROMINENCE FINE STRUCTURES

    SciTech Connect

    Soler, R.; Arregui, I.; Oliver, R.; Ballester, J. L.

    2010-10-20

    We investigate standing kink magnetohydrodynamic (MHD) oscillations in a prominence fine structure modeled as a straight and cylindrical magnetic tube only partially filled with the prominence material and with its ends fixed at two rigid walls representing the solar photosphere. The prominence plasma is partially ionized and a transverse inhomogeneous transitional layer is included between the prominence thread and the coronal medium. Thus, ion-neutral collisions and resonant absorption are the damping mechanisms considered. Approximate analytical expressions of the period, the damping time, and their ratio are derived for the fundamental mode in the thin tube and thin boundary approximations. We find that the dominant damping mechanism is resonant absorption, which provides damping ratios in agreement with the observations, whereas ion-neutral collisions are irrelevant for damping. The values of the damping ratio are independent of both the prominence thread length and its position within the magnetic tube, and coincide with the values for a tube fully filled with the prominence plasma. The implications of our results in the context of the MHD seismology technique are discussed, pointing out that the reported short-period (2-10 minutes) and short-wavelength (700-8000 km) thread oscillations may not be consistent with a standing mode interpretation and could be related to propagating waves. Finally, we show that the inversion of some prominence physical parameters, e.g., Alfven speed, magnetic field strength, transverse inhomogeneity length scale, etc., is possible using observationally determined values of the period and damping time of the oscillations along with the analytical approximations of these quantities.

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

    NASA Astrophysics Data System (ADS)

    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

  2. RapidSeis: Enabling User-Defined Seismological Waveform Data Processing over the Grid

    NASA Astrophysics Data System (ADS)

    Spinuso, Alessandro; Heath, Andy; Koestjer, Jos; Trani, Luca

    2010-05-01

    The objective of this JISC-funded pilot project was to remove perceived barriers to uptake of an application that performs analysis of seismic waveform data. The aim was to provide the seismological community with a simplified system that overcame important barriers such as installation and understanding of the analysis package, location and transfer of large amounts of input data and visualisation of results. The project combined the expertise of three distinct teams. The Orfeus Data Centre provided discovery services and access management to distributed earthquake waveform data and metadata, supported by technologies such as webservices, SPARQL/RDF and a JSR-168 portal framework based on the WSRP portlet architecture. Analysis and visualisation of the waveform data were performed by SDX (Seismic Data eXplorer) developed at the University of Liverpool. SDX formed the core processing engine - this application's functionality can be extended via user-defined algorithms coded as plugins. The processing engine was supported by several webservice-enabled modules used for data and plugin exchange. The user, data and processing infrastructure were connected using the Rapid framework created by the UK National e-Science Centre. Rapid generates intuitive interfaces to the processing core in the form of two self-contained JSR-168 remote portlets. One portlet facilitated plugin creation, whilst the other allowed execution of plugin code within the processing core running on a campus or national Grid infrastructure. The RapidSeis system was deployed within a community gateway: the NERIES web portal. Although RapidSeis originated within the seismological community we suggest it forms a framework which could be exploited in different domains or scientific gateways where users can discover data, store data within a cart and wish to apply specialised processing algorithms remotely through a web browser. Processing performed on Grid infrastructure is completely transparent: the

  3. Waste tires: A future source of activated carbon?

    SciTech Connect

    1996-01-01

    Millions of used tires are disposed in the United States each year, causing major environmental problems and representing a loss of valuable resources. Currently, over 80% of discarded tires are landfilled (approximately 200 million per year). Because tires disposed in municipal landfills rarely stay buried, regulators, landfill operators, and even the general public are constantly reminded of this problem. These ever-surfacing tires can serve as a breeding ground for disease-causing mosquitoes; in addition, large mounds of tires often catch fire, causing significant air pollution. Recent research indicates that used tires may soon represent a source of carbon-based adsorbents and energy-rich liquid and gaseous hydrocarbons. Details of this research are discussed briefly in this paper. 3 refs., 2 figs.

  4. Laser ion source activities at Brookhaven National Laboratory

    DOE PAGESBeta

    Kanesue, Takeshi; Okamura, Masahiro

    2015-07-31

    In Brookhaven National Laboratory (BNL), we have been developing laser ion sources for diverse accelerators. Tabletop Nd:YAG lasers with up to several Joules of energy are mainly used to create ablation plasmas for stable operations. The obtained charge states depend on laser power density and target species. Two types of ion extraction schemes, Direct Plasma Injection Scheme (DPIS) and conventional static extraction, are used depending on application. We optimized and select a suitable laser irradiation condition and a beam extraction scheme to meet the requirement of the following accelerator system. We have demonstrated to accelerate more than 5 x 1010more » of C6+ ions using the DPIS. We successfully commissioned low charge ion beam provider to the user facilities in BNL. As a result, to achieve higher current, higher charge state and lower emittance, further studies will continue.« less

  5. Laser ion source activities at Brookhaven National Laboratory

    SciTech Connect

    Kanesue, Takeshi; Okamura, Masahiro

    2015-07-31

    In Brookhaven National Laboratory (BNL), we have been developing laser ion sources for diverse accelerators. Tabletop Nd:YAG lasers with up to several Joules of energy are mainly used to create ablation plasmas for stable operations. The obtained charge states depend on laser power density and target species. Two types of ion extraction schemes, Direct Plasma Injection Scheme (DPIS) and conventional static extraction, are used depending on application. We optimized and select a suitable laser irradiation condition and a beam extraction scheme to meet the requirement of the following accelerator system. We have demonstrated to accelerate more than 5 x 1010 of C6+ ions using the DPIS. We successfully commissioned low charge ion beam provider to the user facilities in BNL. As a result, to achieve higher current, higher charge state and lower emittance, further studies will continue.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

    correlation and little dispersion throughout the array. These seismic events show an activity burst near the beginning of the seismometer deployment period, when they occur up to once every minute. We discuss the possible sources of these events and how they may be related to ice sheet flow and subglacial hydraulics.

  7. Seismicity of Dronning Maud Land/antarctica As Detected By The Neumayer Seismological Array

    NASA Astrophysics Data System (ADS)

    Eckstaller, A.; Mueller, C.; Hoffmann, M.

    Array seismology provides a powerful tool for improving detection and localization capabilities for monitoring weak seismic events. Little is known about seismic activity of the Antarctic continent due to the sparse station deployment of the global network in this region. To improve monitoring capabilities a small-aperture short-period detec- tion array was installed in the vicinity of the German base Neumayer/Dronning Maud Land. The array complements the Neumayer seismograph network and the broadband seismograph SNAA at the neighbouring South African base Sanae IV. The array was installed in the austral summer season 1997 and has been operational almost continu- ously since that time. The design was adopted from the SPITS-array in Svalbard and consists of 15 short-period vertical seismometers arranged on three concentric rings around the 3-component intermediate-period seismometer in the center. Event detec- tion and beamforming is done automatically using array processing software from NORSAR. With this seismic antenna the number of detected Antarctic earthquakes was increased significantly. In particular, two seismically active regions were identified along the Jutul-Penck-Graben and off Kapp Norvegia. The nature of this seismic activity is not yet fully understood. Especially, the Jutul-Penck-Graben region is of interest since the question arises if this is an active tectonic rift system or if the seismic activity origi- nates from post-glacial rebound movements. Better knowledge of hypocentral depths and focal mechanisms will contribute to the understanding of these mechanisms. An integrated approach by using temporary local networks including geodetical and air- borne geophysical measurements may reveal the mechanisms of these neotectonic dynamics.

  8. A Mid-infrared Census of Star Formation Activity in Bolocam Galactic Plane Survey Sources

    NASA Astrophysics Data System (ADS)

    Dunham, Miranda K.; Robitaille, Thomas P.; Evans, Neal J., II; Schlingman, Wayne M.; Cyganowski, Claudia J.; Urquhart, James

    2011-04-01

    We present the results of a search for mid-infrared signs of star formation activity in the 1.1 mm sources in the Bolocam Galactic Plane Survey (BGPS). We have correlated the BGPS catalog with available mid-IR Galactic plane catalogs based on the Spitzer Space Telescope GLIMPSE legacy survey and the Midcourse Space Experiment (MSX) Galactic plane survey. We find that 44% (3712 of 8358) of the BGPS sources contain at least one mid-IR source, including 2457 of 5067 (49%) within the area where all surveys overlap (10° < ell < 65°). Accounting for chance alignments between the BGPS and mid-IR sources, we conservatively estimate that 20% of the BPGS sources within the area where all surveys overlap show signs of active star formation. We separate the BGPS sources into four groups based on their probability of star formation activity. Extended Green Objects and Red MSX Sources make up the highest probability group, while the lowest probability group is comprised of "starless" BGPS sources which were not matched to any mid-IR sources. The mean 1.1 mm flux of each group increases with increasing probability of active star formation. We also find that the "starless" BGPS sources are the most compact, while the sources with the highest probability of star formation activity are on average more extended with large skirts of emission. A subsample of 280 BGPS sources with known distances demonstrates that mass and mean H2 column density also increase with probability of star formation activity.

  9. Waves & Oscillations in the Solar Atmosphere: Heating and Magneto-Seismology

    NASA Astrophysics Data System (ADS)

    Erdélyi, Robert; Mendoza-Briceno, César A.

    2008-06-01

    Preface; Organizing committee; Conference participants; Address by the Scientific Organizing Committee R. Erdélyi; Progress in coronal seismology B. Roberts; Session 1. Waves and oscillations in solar and stellar interior Robert Erdélyi; Session 2. Coupling of global solar and stellar motions into the lower atmosphere Bernard Roberts; Session 3. Seismology of the lower solar atmosphere and stellar chromospheres Siraj S. Hasan; Session 4. Seismology of open versus closed magnetic structures Marcel Goossens; Session 5. Prominence seismology Jose Luis Ballester; Session 6. Dynamical processes and coupling in the magnetic atmosphere of Sun and stars Miguel Ibañez; Session 7. Wave-particle interactions in magnetized plasmas Cesar A. Mendoza-Briceño; Session 8. Solar and stellar global coronal seismology Viggo Hansteen; Session 9. Fundamental physical processes in coronae: waves, turbulence, reconnection Saku Tsuneta; Session 10. Waves and instabilities in atmospheric plasmas Arnold O. Benz; Summary of meeting Cesar A. Mendoza-Briceño; Concluding remarks A. O. Benz; Late papers; Author index.

  10. 2001 NSLS ACTIVITY REPORT (NATIONAL SYNCHROTRON LIGHT SOURCE).

    SciTech Connect

    CORWIN, M.A.

    2002-05-01

    The year 2001 has been another highly productive year at the NSLS, with over 2500 users, including 720 first time users, conducting nearly 1200 experiments in fields ranging from the life, materials, chemical, and environmental sciences to applied science and technology. An impressive array of highlights from this scientific activity is included in this Activity Report. They include the first demonstration of a direct structural probe of the superconducting ground state in the cuprates by utilizing anomalous soft x-ray resonance effects to selectively enhance the scattering from doped holes. Another highly significant result was the determination of the structure of the potassium channel membrane protein. This is especially significant as it provides insight into how the channel functions and how it selects a particular kind of ion. In the nanoscience area, small angle x-ray scattering measurements played an essential role in determining that preferential sequestering of tailored metal nanocrystals into a self-assembled lamellar diblock copolymer can produce high quality metallodielectric photonic bandgap structures, demonstrating the potential of these nanocomposites for photonic crystal engineering. The infrared microscopy program continued to yield noteworthy results, including an important study that characterized the types and abundances of organic materials in contaminated and uncontaminated sediments from the New York/New Jersey Harbor. These results will be useful in devising improved methods for the destruction or removal of these environmental contaminants.

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

    NASA Astrophysics Data System (ADS)

    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

  12. Using seismology to map water in the mantle transition zone

    NASA Astrophysics Data System (ADS)

    Cobden, Laura; Thio, Vincent; Trampert, Jeannot

    2016-04-01

    the significance of this effect depends on the degree of water saturation and partitioning between the NAMs. Since seismology is better able to constrain the thickness of the transition zone than velocity gradients, our study indicates that the most useful input from future mineral physics experiments would be to better constrain the phase relations between hydrous olivine and its high-pressure polymorphs, especially at high temperatures. Additionally, the uncertainties on the mineral seismic properties could be reduced significantly if the experimentally-observable correlations between bulk and shear moduli and their corresponding pressure derivatives would be published.

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

    NASA Astrophysics Data System (ADS)

    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

  14. ISC-GEM: Global Instrumental Earthquake Catalogue (1900-2009), I. Data collection from early instrumental seismological bulletins

    NASA Astrophysics Data System (ADS)

    Di Giacomo, Domenico; Harris, James; Villaseñor, Antonio; Storchak, Dmitry A.; Engdahl, E. Robert; Lee, William H. K.

    2015-02-01

    In order to produce a new global reference earthquake catalogue based on instrumental data covering the last 100+ years of global earthquakes, we collected, digitized and processed an unprecedented amount of printed early instrumental seismological bulletins with fundamental parametric data for relocating and reassessing the magnitude of earthquakes that occurred in the period between 1904 and 1970. This effort was necessary in order to produce an earthquake catalogue with locations and magnitudes as homogeneous as possible. The parametric data obtained and processed during this work fills a large gap in electronic bulletin data availability. This new dataset complements the data publicly available in the International Seismological Centre (ISC) Bulletin starting in 1964. With respect to the amplitude-period data necessary to re-compute magnitude, we searched through the global collection of printed bulletins stored at the ISC and entered relevant station parametric data into the database. As a result, over 110,000 surface and body-wave amplitude-period pairs for re-computing standard magnitudes MS and mb were added to the ISC database. To facilitate earthquake relocation, different sources have been used to retrieve body-wave arrival times. These were entered into the database using optical character recognition methods (International Seismological Summary, 1918-1959) or manually (e.g., British Association for the Advancement of Science, 1913-1917). In total, ∼1,000,000 phase arrival times were added to the ISC database for large earthquakes that occurred in the time interval 1904-1970. The selection of earthquakes for which data was added depends on time period and magnitude: for the early years of last century (until 1917) only very large earthquakes were selected for processing (M ⩾ 7.5), whereas in the periods 1918-1959 and 1960-2009 the magnitude thresholds are 6.25 and 5.5, respectively. Such a selection was mainly dictated by limitations in time and

  15. Compact laser sources for laser designation, ranging and active imaging

    NASA Astrophysics Data System (ADS)

    Goldberg, Lew; Nettleton, John; Schilling, Brad; Trussel, Ward; Hays, Alan

    2007-04-01

    Recent advances in compact solid sate lasers for laser designation, eye-safe range finding and active imaging are described. Wide temperature operation of a compact Nd:YAG laser was achieved by end pumping and the use of multi-λ diode stacks. Such lasers enabled construction of fully operational 4.7 lb laser designator prototypes generating over 50 mJ at 10-20 Hz PRF. Output pulse energy in excess of 100 mJ was demonstrated in a breadboard version of the end-pumped laser. Eye-safe 1.5 μm lasers based on flash-pumped, low PRF, Monoblock lasers have enabled compact STORM laser range finders that have recently been put into production. To achieve higher optical and electrical efficiency needed for higher PRF operation, Monoblock lasers were end-pumped by a laser diode stack. Laser diode end-pumped Monoblock lasers were operated at 10-20 Hz PRF over a wide temperature range (-20 to +50 °C). Compared with bulk compact solid state lasers, fiber lasers are characterized by lower pulse energy, higher PRF's, shorter pulses and higher electrical efficiency. An example of fiber lasers suitable for LIDAR, and atmospheric measurement applications is described. Eye-safe, low intensity diode pumped solid state green warning laser developed for US Army checkpoint and convoy applications is also described.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Analytical approach to calculation of response spectra from seismological models of ground motion

    USGS Publications Warehouse

    Safak, Erdal

    1988-01-01

    An analytical approach to calculate response spectra from seismological models of ground motion is presented. Seismological models have three major advantages over empirical models: (1) they help in an understanding of the physics of earthquake mechanisms, (2) they can be used to predict ground motions for future earthquakes and (3) they can be extrapolated to cases where there are no data available. As shown with this study, these models also present a convenient form for the calculation of response spectra, by using the methods of random vibration theory, for a given magnitude and site conditions. The first part of the paper reviews the past models for ground motion description, and introduces the available seismological models. Then, the random vibration equations for the spectral response are presented. The nonstationarity, spectral bandwidth and the correlation of the peaks are considered in the calculation of the peak response.

  18. A modified method for the characterisation and activity determination of large area sources.

    PubMed

    Svec, A; Janssen, H; Pernická, L; Klein, R

    2006-01-01

    Large area sources emitting alpha and beta radiations, respectively, are often used for calibrations of surface contamination monitors and meters. It is well known, however, that their properties are strongly influenced by their construction and by their active layer preparation. Non-uniformity of activity distributions over the active surface and the thickness of absorption and backscattering layers cause changes not only in the ratio of particle emission rate and activity but also in emitted particle spectra distributions. Consequently, different sources need to be characterised by one or more parameters related to their emitted particle spectra and used for their activity determination. A modified method based on simple particle absorption spectrometry has been developed. The correlation between a source characteristic parameter and its radiation detection efficiency is utilised for its activity estimation. PMID:16549354

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

    NASA Astrophysics Data System (ADS)

    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

  20. 100+ years of instrumental seismology: the example of the ISC-GEM Global Earthquake Instrumental Catalogue

    NASA Astrophysics Data System (ADS)

    Storchak, Dmitry; Di Giacomo, Domenico

    2015-04-01

    Systematic seismological observations of earthquakes using seismic instruments on a global scale began more than 100 years ago. Since then seismologists made many discoveries about the Earth interior and the physics of the earthquakes, also thanks to major developments in the seismic instrumentation deployed around the world. Besides, since the establishment of the first global networks (Milne and Jesuit networks), seismologists around the world stored and exchanged the results of routine observations (e.g., picking of arrival times, amplitude-period measurements, etc.) or more sophisticated analyses (e.g., moment tensor inversion) in seismological bulletins/catalogues. With a project funded by the GEM Foundation (www.globalquakemodel.org), the ISC and the Team of International Experts released a new global earthquake catalogue, the ISC-GEM Global Instrumental Earthquake Catalogue (1900 2009) (www.isc.ac.uk/iscgem/index.php), which, differently from previous global seismic catalogues, has the unique feature of covering the entire period of instrumental seismology with locations and magnitude re-assessed using modern approaches for the global earthquakes selected for processing (in the current version approximately 21,000). During the 110 years covered by the ISC-GEM catalogue many seismological developments occurred in terms of instrumentation, seismological practice and knowledge of the physics of the earthquakes. In this contribution we give a brief overview of the major milestones characterizing the last 100+ years of instrumental seismology that were relevant for the production of the ISC-GEM catalogue and the major challenges we faced to obtain a catalogue as homogenous as possible.

  1. The fast neutron fluence and the activation detector activity calculations using the effective source method and the adjoint function

    SciTech Connect

    Hep, J.; Konecna, A.; Krysl, V.; Smutny, V.

    2011-07-01

    This paper describes the application of effective source in forward calculations and the adjoint method to the solution of fast neutron fluence and activation detector activities in the reactor pressure vessel (RPV) and RPV cavity of a VVER-440 reactor. Its objective is the demonstration of both methods on a practical task. The effective source method applies the Boltzmann transport operator to time integrated source data in order to obtain neutron fluence and detector activities. By weighting the source data by time dependent decay of the detector activity, the result of the calculation is the detector activity. Alternatively, if the weighting is uniform with respect to time, the result is the fluence. The approach works because of the inherent linearity of radiation transport in non-multiplying time-invariant media. Integrated in this way, the source data are referred to as the effective source. The effective source in the forward calculations method thereby enables the analyst to replace numerous intensive transport calculations with a single transport calculation in which the time dependence and magnitude of the source are correctly represented. In this work, the effective source method has been expanded slightly in the following way: neutron source data were performed with few group method calculation using the active core calculation code MOBY-DICK. The follow-up neutron transport calculation was performed using the neutron transport code TORT to perform multigroup calculations. For comparison, an alternative method of calculation has been used based upon adjoint functions of the Boltzmann transport equation. Calculation of the three-dimensional (3-D) adjoint function for each required computational outcome has been obtained using the deterministic code TORT and the cross section library BGL440. Adjoint functions appropriate to the required fast neutron flux density and neutron reaction rates have been calculated for several significant points within the RPV

  2. ANALYTIC APPROXIMATE SEISMOLOGY OF PROPAGATING MAGNETOHYDRODYNAMIC WAVES IN THE SOLAR CORONA

    SciTech Connect

    Goossens, M.; Soler, R.; Arregui, I.

    2012-12-01

    Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of the solar atmospheric plasma and magnetic field. Here, we present an analytical seismological inversion scheme for propagating MHD waves. This scheme uses the observational information on wavelengths and damping lengths in a consistent manner, along with observed values of periods or phase velocities, and is based on approximate asymptotic expressions for the theoretical values of wavelengths and damping lengths. The applicability of the inversion scheme is discussed and an example is given.

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

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

    the Tanzawa Range to the east. This uplifted body is formed by plate subduction and collision with the Izu Peninsula, and is believed to have influence at significant depth. This is considered to be the reason for the change in the geologic structure beneath Fuji volcano from west to east. The dome structure of the bedrock layer (second layer) directly beneath the summit is considered to have formed in the initial period of volcanic activity that formed Mt. Fuji, leading to the subsequent formation of Komitake volcano, Ko-Fuji volcano and the present day Fuji volcano.

  4. Source localization of ictal epileptic activity investigated by high resolution EEG and validated by SEEG.

    PubMed

    Koessler, Laurent; Benar, Christian; Maillard, Louis; Badier, Jean-Michel; Vignal, Jean Pierre; Bartolomei, Fabrice; Chauvel, Patrick; Gavaret, Martine

    2010-06-01

    High resolution electroencephalography (HR-EEG) combined with source localization methods has mainly been used to study interictal spikes and there have been few studies comparing source localization of scalp ictal patterns with depth EEG. To address this issue, 10 patients with four different scalp ictal patterns (ictal spikes, rhythmic activity, paroxysmal fast activity, obscured) were investigated by both HR-EEG and stereoelectroencephalography (SEEG). Sixty-four scalp-EEG sensors and a sampling rate of 1kHz were used to record scalp ictal patterns. Five different source models (moving dipole, rotating dipole, MUSIC, LORETA, and sLORETA) were used in order to perform source localization. Seven to 10 intracerebral electrodes were implanted during SEEG investigations. For each source model, the concordance between ictal source localization and epileptogenic zone defined by SEEG was assessed. Results were considered to agree if they localized in the same sublobar area as defined by a trained epileptologist. Across the study population, the best concordance between source localization methods and SEEG (9/10) was obtained with equivalent current dipole modeling. MUSIC and LORETA had a concordance of 7/10 whereas sLORETA had a concordance of only 5/10. Four of our patients classified into different groups (ictal spikes, paroxysmal fast activity, obscured) had complete concordance between source localization methods and SEEG. A high signal to noise ratio, a short time window of analysis (<1s) and bandpass filtering around the frequency of rhythmic activity allowed improvement of the source localization results. A high level of agreement between source localization methods and SEEG can be obtained for ictal spike patterns and for scalp-EEG paroxysmal fact activities whereas scalp rhythmic discharges can be accurately localized but originated from seizure propagation network. PMID:20206700

  5. Coseismic and Post-seismic landsliding: insights from seismological modeling and landslide map time series.

    NASA Astrophysics Data System (ADS)

    Marc, Odin; Hovius, Niels; Meunier, Patrick; Uchida, Taro; Gorum, Tolga

    2016-04-01

    Earthquakes impart a catastrophic forcing on hillslopes, that often lead to widespread landsliding and can contribute significantly to sedimentary and organic matter fluxes. We present a new expression for the total area and volume of populations of earthquake-induced landslides.This model builds on a set of scaling relationships between key parameters, such as landslide density, ground acceleration, fault size, earthquake source depth and seismic moment, derived from geomorphological and seismological observations. To assess the model we have assembled and normalized a catalogue of landslide inventories for 40 earthquakes. We have found that low landscape steepness systematically leads to over-prediction of the total area and volume of landslides.When this effect is accounted for, the model is able to predict within a factor of 2 the landslide areas and associated volumes for about two thirds of the cases in our databases. This is a significant improvement on a previously published empirical expression based only on earthquake moment. This model is suitable for integration into landscape evolution models, and application to the assessment of secondary hazards and risks associated with earthquakes. However, it only models landslides associated to the strong ground shaking and neglects the intrinsic permanent damage that also occurred on hillslopes and persist for longer period. With time series of landslide maps we have constrained the magnitude of the change in landslide susceptibility in the epicentral areas of 4 intermediate to large earthquakes. We propose likely causes for this transient ground strength perturbations and compare our observations to other observations of transient perturbations in epicentral areas, such as suspended sediment transport increases, seismic velocity reductions and hydrological perturbations. We conclude with some preliminary observations on the coseismic mass wasting and post-seismic landslide enhancement caused by the 2015 Mw.7

  6. Coronal seismology of flare-excited longitudinal slow magnetoacoustic waves in hot coronal loops

    NASA Astrophysics Data System (ADS)

    Wang, T.; Ofman, L.; Sun, X.; Provornikova, E. A.; Davila, J. M.

    2015-12-01

    The flare-excited longitudinal intensity oscillations in hot flaring loops have been recently detected by SDO/AIA in 94 and 131 bandpasses. These oscillations show similar physical properties (such as period, decay time, and trigger) as those slow-mode standing waves previously detected by the SOHO/SUMER spectrometer in Doppler shift of flare lines formed above 6 MK. The multi-wavelength AIA observations with high spatio-temporal resolution and wide temperature coverage enable us to measure both thermal and wave properties of the oscillating hot plasma with unprecedented accuracy. These new measurements can be used to diagnose the complicated energy transport processes in flare plasma by a technique called coronal seismology based on the combination of observations and MHD wave theory. From a detailed case study we have found evidence for thermal conduction suppression in hot loops by measuring the polytropic index and analyzing the phase relationship between the temperature and density wave signals. This result is not only crucial for better understanding the wave dissipation mechanism but also provides an alternative mechanism to explain the puzzles of long-duration events and X-ray loop-top sources which show much slower cooling than expected by the classical Spitzer conductive cooling. This finding may also shed a light on the coronal heating problem because weak thermal conductivity implies slower cooling of hot plasma in nanoflares, so increasing the average coronal temperature for the same heating rate. We will discuss the effects of thermal conduction suppression on the wave damping and loop cooling based on MHD simulations.

  7. The Role of Crustal Tectonics in Volcano Dynamics (ROCTEVODY) along the Southern Andes: seismological study with emphasis on Villarrica Volcano

    NASA Astrophysics Data System (ADS)

    Mora-Stock, Cindy; Tassara, Andrés

    2016-04-01

    The Southern Andean margin is intrinsically related to the Liquiñe-Ofqui Fault Zone (LOFZ), a 1000 km-long dextral strike-slip arc-parallel fault on which most of the volcanic centers of the Southern Volcanic Zone (SCVZ) of the Andes are emplaced. At large spatial (102 - 103 km) and temporal (105 - 107 yr) scales, regional tectonics linked to partitioning of the oblique convergence controls the distribution of magma reservoirs, eruption rates and style, as well as the magma evolution. At small scales in space (< 102 km) and time (10‑1 - 102 yr), stress transfer mechanisms between magma reservoirs and seismically-active faults are though to transiently change the regional stress field, thus leading to eruptions and fault (re)activation. However, the mechanisms by which the interaction between (megathrust and crustal) earthquakes and volcanic eruptions actually occur, in terms of generating the relationships and characteristics verified at the long term, are still poorly understood. Since 2007, the Southern Andean margin has presented an increase of its tectonic and eruptive activity with several volcanic crisis and eruptions taking place in association with significant seismicity clusters and earthquakes both in the megathrust and the LOFZ. This increased activity offers a unique opportunity to improve our understanding of the physical relation between contemporary tectono-volcanic processes and the long-term construction of the LOFZ-SVZ system. Taking advantage of this opportunity by means of an integrated analysis of geodetic and seismological data through finite element numerical modeling at the scale of the entire margin and for selected cases is the main goal of project Active Tectonics and Volcanism at the Southern Andes (ACT&VO-SA, see Tassara et al. this meeting). Into the framework of the ACT&VO-SA project, the complementary ROCTEVODY-Villarrica project concentrates on the role that inherited crustal structures have in the volcano dynamics. The focus is

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  9. Local Seismological Networks in Northern Baja California: Some Interpretation of Results.

    NASA Astrophysics Data System (ADS)

    Frez, J.; Acosta, J.; Nava, F.; Gonzalez, J.; Alvarez, M.

    2002-12-01

    Since 1997, we have installed local seismological networks in northern Baja California (Reftek stations, three digital components, one to four months operation, covering areas of about 50 km x 50 km) for detailed microseismicity surveys of several fault systems in the region: Cerro Prieto, San Miguel, Agua Blanca, Sierra Juarez, and areas in between. Immediate results are location of about 1500 hypocenters, determination of about 400 focal mechanisms, and some structural information on the crust. In this presentation, we focus on: a) a summary of the spatial distribution of the hypocenters, focal mechanisms, and P and T axes; b) the role of the Ojos Negros Valley in the regional seismotectonics, and c) the existence of orthogonal alignments of epicenters not necessarily associated with mapped fault traces. Most of the activity is not clearly associated with fault traces: the exception is the SE segment of the San Miguel fault, the same one where destructive earthquakes occurred in 1954 and 1956. Most of the activity appears to be correlated with valleys (Ojos Negros, Trinidad-San Matias), or to simply occur between fault traces, or to belong to epicenter alignments of ~15 km or more in length which are part of longer segments that are apparent in regional seismicity maps (SCSN and RESNOM catalogs). This regional and local alignments show an orthogonal pattern. In a simple interpretation, they could represent a very new fracture proccess in a still mostly homogeneous material, not yet expressed as fault ruptures. All P and T axes azimuthal distributions from the various areas of study show a well defined global maximum consistent with the direction of regional stresses (about NS and EW, for P and T axes, respectively). However, the P axes are distributed on the focal sphere as an almost NS strip, particularly for the Ojos Negros Valley, indicating an extensional regime.

  10. HerMES: disentangling active galactic nuclei and star formation in the radio source population

    NASA Astrophysics Data System (ADS)

    Rawlings, J. I.; Page, M. J.; Symeonidis, M.; Bock, J.; Cooray, A.; Farrah, D.; Guo, K.; Hatziminaoglou, E.; Ibar, E.; Oliver, S. J.; Roseboom, I. G.; Scott, Douglas; Seymour, N.; Vaccari, M.; Wardlow, J. L.

    2015-10-01

    We separate the extragalactic radio source population above ˜50 μJy into active galactic nuclei (AGN) and star-forming sources. The primary method of our approach is to fit the infrared spectral energy distributions (SEDs), constructed using Spitzer/IRAC (Infrared Array Camera) and Multiband Imaging Photometer for Spitzer (MIPS) and Herschel/SPIRE photometry, of 380 radio sources in the Extended Chandra Deep Field-South. From the fitted SEDs, we determine the relative AGN and star-forming contributions to their infrared emission. With the inclusion of other AGN diagnostics such as X-ray luminosity, Spitzer/IRAC colours, radio spectral index and the ratio of star-forming total infrared flux to k-corrected 1.4 GHz flux density, qIR, we determine whether the radio emission in these sources is powered by star formation or by an AGN. The majority of these radio sources (60 per cent) show the signature of an AGN at some wavelength. Of the sources with AGN signatures, 58 per cent are hybrid systems for which the radio emission is being powered by star formation. This implies that radio sources which have likely been selected on their star formation have a high AGN fraction. Below a 1.4 GHz flux density of 1 mJy, along with finding a strong contribution to the source counts from pure star-forming sources, we find that hybrid sources constitute 20-65 per cent of the sources. This result suggests that hybrid sources have a significant contribution, along with sources that do not host a detectable AGN, to the observed flattening of the source counts at ˜1 mJy for the extragalactic radio source population.

  11. Dipole source localization of interictal epileptiform activity in temporal lobe epilepsy with medial temporal lesion.

    PubMed

    Mine, S; Iwasa, H; Nakajima, Y; Yamaura, A

    2000-02-01

    Dipole sources of interictal epileptiform activities recorded by conventional electroencephalogram (EEG) were estimated using the dipole tracing method. Four cases of temporal lobe epilepsy with medial temporal lesions were studied. Two patients with hippocampal sclerosis, one patient with granulation in the hippocampus and one patient with cavernous angioma were involved in the study. Interictal epileptiform activities were classified into two patterns according to the topography of spikes. They were widespread spikes over the parasagittal electrodes (parasagittal spikes) and restricted spikes at the temporal electrodes (temporal spikes). Dipole sources of parasagittal spikes were localized in the medio-basal temporal lobe with vertically orientated vector moment. Dipole sources of temporal spikes were localized in the medio-basal temporal lobe with horizontally orientated vector moment. Locations of dipoles and directions of vector moments were consistent with topography and polarity of spikes. The difference in the two patterns of interictal epileptiform activities was derived from the difference in the direction of the vector moment of dipole sources. There was no difference in the location of dipole sources. Both the dipole sources and the lesions were localized in the same medio-basal temporal lobe. Dipole tracing was very useful in localizing the dipole sources of interictal epileptiform activities and in understanding the neurophysiological background. PMID:15558875

  12. Use of active source geophones for passive source imaging: Examples from Bighorn Arch Seismic Experiment (BASE), USA

    NASA Astrophysics Data System (ADS)

    Sheehan, A.; O'rourke, C. T.; Haines, S. S.; Yang, Z.; Worthington, L. L.; Miller, K. C.

    2013-05-01

    In this paper we explore the variety of active and passive source deep seismic imaging that can be performed using continous wavefield recordings from a dense array of industry-style geophones. The data in this study were acquired during the 2009-10 EarthScope FlexArray Bighorn Arch Seismic Experiment(BASE) in central Wyoming, USA. In addition to traditional active and passive source seismic data acquisition, BASE included a deployment of 850 Reftek RT125 " Texan" dataloggers that produced continuous recording over 14 days. Ground motion was recorded via Geospace GS-11 4.5 Hz single channel vertical component geophones. The geophones were deployed in a grid of three E-W lines and two N-S lines across the Bighorn Mountains. We find that the high frequency geophones effectively record the P waves of teleseismic earthquakes. During the 15 days of continuous recording we observed 57 teleseismic events with pickable P-wave arrivals across the array, providing over 10,000 travel times (P, PKiKP, Pdiff, Pn) suitable for teleseismic tomography. The full waveforms can be used to extract additional information about the subsurface. We have successfully utilized teleseismic receiver-side crustal reverberation phases as virtual sources to mimic crustal reflection profiles (Yang et al., 2012). After depth conversion, we find a coherent phase that correlates well with the top of the Madison Formation under the Powder River and Bighorn Basins that flank the Bighorn Mountains. In addition, we combine the phases PpPdp from single-channel geophone recordings and Ps from three-component recordings to constrain the average Vp /Vs ratio for the sedimentary strata. Following Haines (2011), we are exploring the use of interferometric processing of active source blasts. In principle, virtual source and receiver gathers can be created through cross-correlation of full wavefields. The seismic interferometry provides a means of simulating alternative acquisition geometries, and has the

  13. Active sand dunes are largest dust source in the Sahara Desert

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Atreyee

    2012-09-01

    Dried up lakebeds and playas in the Sahara Desert of North Africa are large sources of dust in the atmosphere. The Bodélé Depression at the southern edge of the Sahara Desert, for example, is the single largest source of dust in the world; on average, 100 dust storms a year originate from the Bodélé Depression. A new study by Crouvi et al., however, finds that active sand dunes could be even bigger sources of desert dust in the atmosphere. Atmospheric dust plays active roles in climate and biological processes in the ocean: It regulates heating at the surface of the Earth; modifies cloud properties that affect rainfall; and acts as the only source of iron, a critical nutrient for microorganisms in the ocean. Little is known about types of dust sources in the Sahara Desert, which alone accounts for more than 50% of the dust in the atmosphere.

  14. Preliminary results of vibrator-aided experiments in non-linear seismology conducted at Uetze, F.R.G.

    NASA Astrophysics Data System (ADS)

    Dimitriu, Petros P.

    1990-10-01

    Following acoustics and largely thanks to the pioneering work of a group of Soviet geophysicists, the study of non-linear elastic properties and their effects is becoming an active field of research in geophysics. The research so far has produced a substantial body of evidence indicating that earth materials, from soils to crystalline rocks, are much more non-linear than is commonly believed and certainly far more non-linear than the materials usually used and studied in acoustics. But although most of the evidence comes from vibrator-aided experiments, apparently best suited for investigating the non-linearity of the geophysical medium owing to the ability of modern vibrators to generate seismic signals of prescribed form, the absence of a standard experimental technique makes it difficult to estimate and compare the various results, particularly in view of the considerable non-linearity of the source (vibrator-ground system) itself. The aim of the present vibrator-aided experiments was to try to confirm certain results in non-linear seismology, particularly the effects of harmonic generation and non-linear interaction in vibrator-induced sinusoidal seismic waves, by using an experimental method designed to enable one to discriminate between source, near-field and far-field non-linear effects. In the experiments, two identical prospecting vibrators, installed on the ground surface some 16 m apart, were driven in the harmonic regime separately and simultaneously (tests on non-linear evolution and interaction), a wide range of excitation frequencies and amplitudes being covered, and the resulting ground-surface motion was picked up by an array consisting of 48 groups of 12 vertical geophones-velocimeters and recorded, in multiplex form, by a prospecting seismic station. Tests were made first for short and intermediate source-receiver distances (near field, distance range covered 0-200 m, 5-m spacing of geophone groups), then for large distances (far field, range 1

  15. Agent-based power sharing scheme for active hybrid power sources

    NASA Astrophysics Data System (ADS)

    Jiang, Zhenhua

    The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

  16. EEG and MEG: sensitivity to epileptic spike activity as function of source orientation and depth.

    PubMed

    Hunold, A; Funke, M E; Eichardt, R; Stenroos, M; Haueisen, J

    2016-07-01

    Simultaneous electroencephalography (EEG) and magnetoencephalography (MEG) recordings of neuronal activity from epileptic patients reveal situations in which either EEG or MEG or both modalities show visible interictal spikes. While different signal-to-noise ratios (SNRs) of the spikes in EEG and MEG have been reported, a quantitative relation of spike source orientation and depth as well as the background brain activity to the SNR has not been established. We investigated this quantitative relationship for both dipole and patch sources in an anatomically realistic cortex model. Altogether, 5600 dipole and 3300 patch sources were distributed on the segmented cortical surfaces of two volunteers. The sources were classified according to their quantified depths and orientations, ranging from 20 mm to 60 mm below the skin surface and radial and tangential, respectively. The source time-courses mimicked an interictal spike, and the simulated background activity emulated resting activity. Simulations were conducted with individual three-compartment boundary element models. The SNR was evaluated for 128 EEG, 102 MEG magnetometer, and 204 MEG gradiometer channels. For superficial dipole and superficial patch sources, EEG showed higher SNRs for dominantly radial orientations, and MEG showed higher values for dominantly tangential orientations. Gradiometers provided higher SNR than magnetometers for superficial sources, particularly for those with dominantly tangential orientations. The orientation dependent difference in SNR in EEG and MEG gradually changed as the sources were located deeper, where the interictal spikes generated higher SNRs in EEG compared to those in MEG for all source orientations. With deep sources, the SNRs in gradiometers and magnetometers were of the same order. To better detect spikes, both EEG and MEG should be used. PMID:27328313

  17. NSLS 2007 Activity Report (National Synchrotron Light Source Activity Report 2007)

    SciTech Connect

    Miller ,L.; Nasta, K.

    2008-05-01

    The National Synchrotron Light Source is one of the world's most productive and cost-effective user facilities. With 2,219 individual users, about 100 more than last year, and a record-high 985 publications, 2007 was no exception. In addition to producing an impressive array of science highlights, which are included in this Activity Report, many NSLS users were honored this year for their scientific accomplishments. Throughout the year, there were major strides in the development of the scientific programs by strengthening strategic partnerships with major research resources and with the Center for Functional Nanomaterials (CFN). Of particular note, the Consortium for Materials Properties Research in Earth Sciences (COMPRES) received renewed funding for the next five years through the National Science Foundation. COMPRES operates four high-pressure NSLS beamlines--X17B2, X17B3, X17C, and U2A--and serves the earth science community as well as the rapidly expanding segment of researchers using high-pressure techniques in materials, chemical, and energy-related sciences. A joint appointment was made between the NSLS and Stony Brook University to further enhance interactions with COMPRES. There was major progress on two key beamline projects outlined in the Five-Year Strategic Plan: the X25 beamline upgrade and the construction of the X9 small angle scattering (SAXS) beamline. The X25 overhaul, which began with the installation of the in-vacuum mini-gap undulator (MGU) in January 2006, is now complete. X25 is once again the brightest beamline for macromolecular crystallography at the NSLS, and in tandem with the X29 undulator beamline, it will keep the NSLS at the cutting edge in this important area of research. Upgrade work associated with the new MGU and the front end for the X9 SAXS beamline--jointly developed by the NSLS and the CFN--also was completed. Beamline X9 will host the SAXS program that currently exists at beamline X21 and will provide new microbeam SAXS

  18. The Showa Sanriku earthquake of 02 March 1933: A global seismological reassessment

    NASA Astrophysics Data System (ADS)

    Okal, Emile A.; Kirby, Stephen H.; Kalligeris, Nikos

    2016-06-01

    After 83 years, the great normal-faulting earthquake of 02 March 1933, which took place off the Japan Trench and produced a devastating tsunami on the Sanriku coast and damaging waves in Hawaii, remains the largest recorded normal-faulting earthquake. This study uses advanced methods to investigate this event using far-field seismological and tsunami data and complements a sister study by Uchida et al. [2015] which used exclusively arrival times at Japanese stations. Our relocation of the mainshock (39.22°N, 144.45°E, with a poorly constrained depth of less than 40 km) places it in the outer trench slope, below a seafloor depth of ˜ 6500 m, in a region of horst-and-graben structure, with fault scarps approximately parallel to the axis of the Japan Trench. Relocated aftershocks show a band of genuine shallow aftershocks parallel to the Japan Trench under the outer-trench slope and a region of post-mainshock events landward of the trench axis that occur over roughly the same latitude range and are thought to be the result of stress transfer to the interplate thrust boundary following the normal-faulting rupture. Based on a combination of P-wave first motions and inversion of surface-wave spectral amplitudes, we propose a normal faulting focal mechanism (φ = 200°, δ = 61°, λ = 271°), and a seismic moment M0 = (7±1) × 1028 dyn*cm (Mw = 8.5). A wide variety of data, including the distribution of isoseismals, the large magnitudes (up to 8.9) proposed by early investigators before the standardization of magnitude scales, estimates of energy-to-moment ratios, and the tentative identification of a T wave at Pasadena (and possibly Riverside), clearly indicate that this seismic source was exceptionally rich in high-frequency wave energy, suggesting a large apparent stress and a sharp rise time, and consistent with the behavior of many smaller shallow normal-faulting earthquakes. Hydrodynamic simulations based on a range of possible sources consistent with the above

  19. THE ENVIRONMENT AND DISTRIBUTION OF EMITTING ELECTRONS AS A FUNCTION OF SOURCE ACTIVITY IN MARKARIAN 421

    SciTech Connect

    Mankuzhiyil, Nijil; Ansoldi, Stefano; Tavecchio, Fabrizio

    2011-05-20

    For the high-frequency-peaked BL Lac object Mrk 421, we study the variation of the spectral energy distribution (SED) as a function of source activity, from quiescent to active. We use a fully automatized {chi}{sup 2}-minimization procedure, instead of the 'eyeball' procedure more commonly used in the literature, to model nine SED data sets with a one-zone synchrotron self-Compton (SSC) model and examine how the model parameters vary with source activity. The latter issue can finally be addressed now, because simultaneous broadband SEDs (spanning from optical to very high energy photon) have finally become available. Our results suggest that in Mrk 421 the magnetic field (B) decreases with source activity, whereas the electron spectrum's break energy ({gamma}{sub br}) and the Doppler factor ({delta}) increase-the other SSC parameters turn out to be uncorrelated with source activity. In the SSC framework, these results are interpreted in a picture where the synchrotron power and peak frequency remain constant with varying source activity, through a combination of decreasing magnetic field and increasing number density of {gamma} {<=} {gamma}{sub br} electrons: since this leads to an increased electron-photon scattering efficiency, the resulting Compton power increases, and so does the total (= synchrotron plus Compton) emission.

  20. Activation analysis of indium, KCl, and melamine by using a laser-induced neutron source

    NASA Astrophysics Data System (ADS)

    Lee, Sungman; Lee, Kitae; Cha, Hyungki

    2014-04-01

    A laser-induced repetitively operated fast neutron source with a neutron yield of 4 × 105 n/pulse and a pulse repetition rate of 5 Hz, which was developed using a deuterated polystyrene film target and a 24-TW femtosecond laser, was applied for laser activation analyses of indium, KCl, and melamine samples. The nuclear reactions of the measured gamma spectra for the activated samples were identified as (n, γ), (n, n'), and (n, 2n) reactions. These indicate possible usage of the neutron source for practical activation analyses of various materials.

  1. Source activity correlation effects on LCMV beamformers in a realistic measurement environment.

    PubMed

    Belardinelli, Paolo; Ortiz, Erick; Braun, Christoph

    2012-01-01

    In EEG and MEG studies on brain functional connectivity and source interactions can be performed at sensor or source level. Beamformers are well-established source-localization tools for MEG/EEG signals, being employed in source connectivity studies both in time and frequency domain. However, it has been demonstrated that beamformers suffer from a localization bias due to correlation between source time courses. This phenomenon has been ascertained by means of theoretical proofs and simulations. Nonetheless, the impact of correlated sources on localization outputs with real data has been disputed for a long time. In this paper, by means of a phantom, we address the correlation issue in a realistic MEG environment. Localization performances in the presence of simultaneously active sources are studied as a function of correlation degree and distance between sources. A linear constrained minimum variance (LCMV) beamformer is applied to the oscillating signals generated by the current dipoles within the phantom. Results show that high correlation affects mostly dipoles placed at small distances (1, 5 centimeters). In this case the sources merge. If the dipoles lie 3 centimeters apart, the beamformer localization detects attenuated power amplitudes and blurred sources as the correlation level raises. PMID:22611439

  2. CSDP: the seismology of continental thermal regimes. Final technical report, January 1, 1975-December 31, 1984

    SciTech Connect

    Aki, K.

    1985-02-01

    Research progress is reported in the development of new seismological tools to define and characterize the geometry, mechanical construction and mass transport process of a geothermal system, and their application to various geothermal systems including the Fenton Hill Hot Dry Rock System, New Mexico, Kilauea and Kilauea Iki, Hawaii, Mt. St. Helens, Washington, and Long Valley, California. (ACR)

  3. Geologic and seismologic investigations for Rocky Flats Plant. Volume II. Appendices. Final report

    SciTech Connect

    Not Available

    1981-07-01

    This volume contains the results of a seismic refraction study of the Ralston Reservoir area, soil stratigraphic investigations, unit descriptions, an analysis of geodetic data, experimental models, seismological evaluation, a seismicity survey of the Northern Golden Fault, historical data for the November 7, 1882 earthquake, and a dendrochronology study. (ACR)

  4. NSLS 2005 ACTIVITY REPORT (NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 2005).

    SciTech Connect

    MILLER, L.

    2006-05-01

    In 2005, the NSLS proved itself, once again, to be a center of scientific excellence. This remarkable facility, commissioned in the early 1980s, is still attracting some of the world's best researchers in almost every scientific field, who produce more than seven hundred scientific papers every year using the NSLS. The 'Science Highlights' and 'Feature Highlights' sections of this report are just a small sampling of the many, many impressive research projects conducted at the NSLS in 2005. For example, a user group synthesized and studied zinc-oxide nanowires, which have applications in many optical and electrical devices. Another user group studied how strontium and uranium are removed from high-level radioactive waste. And in another interesting study, users deciphered the basis for antibiotic resistance. However, as always, the success of these projects depends on the performance of the facility. Again this year, the rings were in top form--reliability was 96 percent for the x-ray ring and 99 percent for the VUV-IR ring. Additionally, to keep the NSLS as productive as possible and to continue to attract users, many beamline upgrade projects were completed this year. One of the highlights of these upgrades is the new mini-gap undulator installed at beamline X25. This insertion device is providing a much brighter x-ray source for the program at X25. In the always important area of safety, several noteworthy activities took place this year. In particular, NSLS staff made a major commitment to labeling and inspecting electrical equipment. And perhaps the best news is what didn't happen--there were no reportable occurrences related to environmental, safety, or health issues in 2005, and no injuries that resulted in restricted or lost time. We all owe thanks to the dedicated NSLS staff and users who have ensured that the NSLS remains a reliable, safe, up-to-date research facility. As 2005 came to an end, I stepped down as NSLS Chairman in order to focus my primary

  5. Imaging the magmatic system of Newberry Volcano using Joint active source and teleseismic tomography

    NASA Astrophysics Data System (ADS)

    Heath, Benjamin A.; Hooft, Emilie E. E.; Toomey, Douglas R.; Bezada, Maximiliano J.

    2015-12-01

    In this paper, we combine active and passive source P wave seismic data to tomographically image the magmatic system beneath Newberry Volcano, located east of the Cascade arc. By using both travel times from local active sources and delay times from teleseismic earthquakes recorded on closely spaced seismometers (300-800 m), we significantly improve recovery of upper crustal velocity structure (<10 km depth). The tomographic model reveals a low-velocity feature between 3 and 5 km depth that lies beneath the caldera, consistent with a magma body. In contrast to earlier tomographic studies, where elevated temperatures were sufficient to explain the recovered low velocities, the larger amplitude low-velocity anomalies in our joint tomography model require low degrees of partial melt (˜10%), and a minimum melt volume of ˜2.5 km3. Furthermore, synthetic tests suggest that even greater magnitude low-velocity anomalies, and by inference larger volumes of magma (up to 8 km3), are needed to explain the observed waveform variability. The lateral extent and shape of the inferred magma body indicates that the extensional tectonic regime at Newberry influences the emplacement of magmatic intrusions. Our study shows that jointly inverting active source and passive source seismic data improves tomographic imaging of the shallow crustal seismic structure of volcanic systems and that active source experiments would benefit from longer deployment times to also record teleseismic sources.

  6. Seismological evidence and dynamic model of reverse rupture propagation during the 2010 M7.2 El Mayor Cucapah earthquake

    NASA Astrophysics Data System (ADS)

    Meng, L.; Ampuero, J. P.; Page, M. T.; Hudnut, K. W.

    2011-12-01

    The 2010 El Mayor-Cucapah earthquake has produced some unique observations that exemplify the complexity of rupture dynamics. An eyewitness located near the fault when the rupture broke reported signatures of reverse surface rupture (rupture towards the South at a location North from the hypocenter). We report here on seismological evidence of this phenomenon and present dynamic rupture simulations that illustrate a possible mechanism. Reverse rupture propagation is not admissible in traditional source inversions, because of restrictive assumptions about the rupture kinematics adopted to reduce the non-uniqueness of the inverse problem. In contrast, source imaging by back-projection of dense array data is free from such assumptions. Recently, we have enhanced the array back-projection technique to achieve higher resolution on rupture evolution. We have also extended this approach to recordings at regional distance, despite the complexity of the regional Pn waveforms. We imaged the source of the El Mayor-Cucapah earthquake by back-projecting Pn waves recorded by the SIEDCAR array in New Mexico. Our analysis reveals a segment with reverse rupture propagation consistent with the eyewitness reports. Our simulations of dynamic earthquake rupture show that reverse rupture propagation can be caused by delayed rupture of a strong fault region with a negative along-strike gradient of strength excess. In this scenario the rupture front tunnels through (or surrounds) the strong area, then starts breaking the opposite, weaker end of the strong patch, inducing a reverse rupture front.

  7. Seismological aspects of the 1988 1989 Lonquimay (Chile) volcanic eruption

    NASA Astrophysics Data System (ADS)

    Barrientos, Sergio E.; Acevedo-Aránguiz, Patricio S.

    1992-11-01

    More than 1600 earthquakes were recorded, in a four-month period, on portable seismographic stations installed in the Lonquimay area, immediately after the initiation of the volcanic eruption of December 25, 1988. Hypocentral parameters were calculated on a subset of 150 events showing clear P and S arrivals. Seismic activity was restricted to a north-south elongated region that included the main crater of the Lonquimay volcano. The new Navidad crater lies along the eastern margin of the area of seismicity. Most of the hypocenters are located at depths shallower than 6 km and none have depths exceeding 10 km. The largest earthquakes of the sequence took place on Dec. 28 ( M=4.7), Jan. 12-13 ( M= 4.8 and 5.0), and Feb. 24 ( M=5.3). The number of events per day varied; it peaked on Dec. 27 with more than 260 events, and more than 200 events were recorded on Jan. 13, both of which corresponded to the days of large earthquakes. The relation of large to small events given by the b value of the magnitude-frequency distribution Log N=a - bM is typical of volcanic sequences ( b=1.7) and much larger than the equivalent for tectonic environments. The rate of decay of the number of aftershocks of each large earthquake is proportional to t -P with p increasing from 0.63 to 1.08 as the eruption progressed in time. Initial low values of p indicate a slow stress release in the region. Larger absolute values of p are comparable with tectonic environments and might be indicators of the last stages of the eruption process. The total seismic energy release is 9.6 × 10 19 ergs , about five orders of magnitude less than the estimated thermal energy. The spatial distribution of earthquakes suggests that the sources of stress change associated with the eruption are located under, and possibly to the south of, the main crater of the Lonquimay volcano, and that the evacuation channels of magma occupied a zone of weakness in the region of the new crater.

  8. The Dahuiyeh (Zarand, Iran) Earthquake of 22 February 2005, Ms6.5, A preliminary Field and Seismological Observation

    NASA Astrophysics Data System (ADS)

    Zare, M.

    2005-12-01

    1. Introduction: The Dahuiyeh earthquake 22/02/2005, has shocked a seismically active area in SW of Iran in Kerman Province. The region is known by the previous earthquakes occurred in this region; specially the earthquake of 19 December 1977, Mw5.9 (Gisk-Bantangal, North of Zarand) which caused more than 500 life losses and was originated from the reactivation of the Kuhbanan fault (a right-lateral strike slip fault with a length of about 100km). The recent earthquake caused a life loss of more than 600 persons and more than 2000 injured people. Two villages of Dahuiyeh and Hutkan were demolished totally, where the most of the life losses were observed. The damages in the village of Hutkan were corresponded to the location of the village houses in a slop of about 45 degree. On the other hand the damages were amplified in the epicentral region due to a heavy rain and snow fall, which caused heavier roofs, and more suitable conditions for collapse. The maximum intensity of XIII-IX (EMS98) could be assigned to the macroseismic region. 2. Seismotectonic and source parameters The recent earthquake of 22/02/2005 was originated evidently from the reactivation of Dahuiyeh fault, a compressional fault that reaches to the Kuhbanan fault at the place of the Dahuiyeh village. The mechanism of the event was compressional (according to Harvard) and compressional with a right-lateral strike slip component (according to NEIC report). The fault plane had a dip towards north. The event was recorded in 12 stations of the IIEES national seismological network. A Mw6.5 was estimated for the mainshock using the assessment of moment magnitude for the recorded accelerograms having acceptable signal to noise ratio. A magnitude of Ms6.5 was estimated for this event according to the record obtained in Maku station with an epicentral distance of about 1400km. The earthquake fault was observed along an previously mapped fault (Dahuiyeh fault) having an east-west trend and making a surface

  9. 1994-2004 : Ten years of European effort for education in Seismology

    NASA Astrophysics Data System (ADS)

    Virieux, J.; Zollo, A.; Lomax, A.; Berenguer, J.; Laj, C.; Bobbio, A.

    2004-12-01

    Following trends of the pioneer PEPP project in USA, an European group has investigated since 1994 how to promote physics and earth sciences and, more specifically, how to educate scientifically and socially young generations to environmental hazards. Seismology has been selected as the vehicle for a prototypical ten-years experience of teaching and learning sciences in European high schools accounting for the specificity and differencies of educational systems in each country. This general purpose has required competences and strong interactions of both teachers, researchers and high school students. Over ten years of continuous activities, these people have found that the target was very ambitious and that both high-tech efforts as well as very focused teaching procedures must be set on. Dedicated instruments were developped in two years through interactions between researchers,teachers and students in order to fit both the scientific quality but also pedagogical features and were installed in different parts of Europe. The sequence of Colfiorito Earthquakes in September-October 1997 was the first data collected simultaneously in different European schools. Since then, more thant 50 stations have been deployed over Europe and data have been made available for education purposes. Data from these seismic stations have been used as the back-bone for interactions between students/pupils, teachers and researchers leading to the development of dedicated teaching and learning materials as software tools for data analysis, simple experimentations and so on. The framework for such an European initiative has been provided by Italian and French national funds and put together under the banner of the so-called EDUSEIS projet. This EDUcational SEISmological European Network (http://www.eduseis.org/) has shown that indeed environmental education is possible with its typical feature of long-term efforts. Funding through Europe will certainly increase the cohesion of this

  10. AlpArray - a broad(band) seismology initiative on the European Alps

    NASA Astrophysics Data System (ADS)

    Hetényi, G.

    2012-12-01

    thickness variations), using different methodologies in the sub-regions of interest. An overview of these targets and the methodologies intended to be applied in connection with the seismological measurements will be presented. The geodynamic interpretation of the acquired data will be complemented by other Earth Science disciplines such as state-of-the-art numerical and analogue modelling, gravity and magneto-telluric measurements, as well as structural geology. In conclusion, we hope to turn the strong community interest into a truly interdisciplinary and collaborative project in the key region for seismotectonic activity and dynamics of Europe. At this poster we welcome anybody who is interested to hear more on the project, who would like share their experience with similar large-scale field experiment(s), and/or who has scientific, practical or funding advice.

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

    NASA Astrophysics Data System (ADS)

    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

  12. The MEG topography and the source model of abnormal neural activities associated with brain lesions

    SciTech Connect

    Ueno, S.; Iramina, K.; Ozaki, H.; Harada, K.

    1986-09-01

    A source model is proposed to simulate spatial distributions of abnormal MEG and EEG activities generated by abnormal neural activities such as the delta activity associated with brain tumors. Brain tumor itself is electrically silent and the spherical shell around the tumor might generate abnormal neural activities. The sources of these neural activities are represented by combinations of multiple current dipoles. The head is assumed to be a spherical volume conductor. Electrical potentials and magnetic fields over the surface of the spheres are calculated. The computer simulation shows that the MEG topography and EEG topography vary variously with combinations of location and orientation of the dipoles. In a special case, however, that the dipoles orient in the same direction or orient radially, the spatial patterns of the MEGs and EEGs generated by numerous dipoles are analogous to those generated by single dipoles.

  13. Measurement of the activity of an artificial neutrino source based on {sup 37}Ar

    SciTech Connect

    Abdurashitov, D. N.; Veretenkin, E. P.; Gavrin, V. N.; Gorbachev, V. V.; Ibragimova, T. V.; Kalikhov, A. V.; Mirmov, I. N. Shikhin, A. A.; Yants, V. E.; Barsanov, V. I.; Dzhanelidze, A. A.; Zlokazov, S. B.; Markov, S. Yu.; Shakirov, Z. N.; Cleveland, B. T.

    2007-02-15

    The activity of an artificial neutrino source based on {sup 37}Ar was measured by a specially developed method of directly counting {sup 37}Ar decays in a proportional counter. This source was used to irradiate the target of the SAGE radiochemical gallium-germanium neutrino telescope at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences, Moscow), whereupon the measurements were performed at the Institute of Reactor Materials (Zarechny, Sverdlovsk oblast, Russia). The method used to prepare gaseous samples for measurements in proportional counters and the counting procedure are described. The measured activity of the {sup 37}Ar neutrino source is 405.1 {+-} 3.7 kCi (corrected for decays that occurred within the period between the instant of activity measurement and the commencement of the irradiation of Ga target at 04:00 Moscow time, 30.04.2004)

  14. A laser-induced repetitive fast neutron source applied for gold activation analysis

    NASA Astrophysics Data System (ADS)

    Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki

    2012-12-01

    A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 × 105 n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He4 nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T3.

  15. A laser-induced repetitive fast neutron source applied for gold activation analysis

    SciTech Connect

    Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki

    2012-12-15

    A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 Multiplication-Sign 10{sup 5} n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He{sup 4} nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T{sup 3}.

  16. A laser-induced repetitive fast neutron source applied for gold activation analysis.

    PubMed

    Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki

    2012-12-01

    A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 × 10(5) n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He(4) nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T(3). PMID:23277984

  17. Evidence for Infrared-faint Radio Sources as z > 1 Radio-loud Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Huynh, Minh T.; Norris, Ray P.; Siana, Brian; Middelberg, Enno

    2010-02-01

    Infrared-Faint Radio Sources (IFRSs) are a class of radio objects found in the Australia Telescope Large Area Survey which have no observable mid-infrared counterpart in the Spitzer Wide-area Infrared Extragalactic (SWIRE) survey. The extended Chandra Deep Field South now has even deeper Spitzer imaging (3.6-70 μm) from a number of Legacy surveys. We report the detections of two IFRS sources in IRAC images. The non-detection of two other IFRSs allows us to constrain the source type. Detailed modeling of the spectral energy distribution of these objects shows that they are consistent with high-redshift (z >~ 1) active galactic nuclei.

  18. Variations in fluid transport and seismogenic properties in the Lesser Antilles subduction zone: constraints from joint active-source and local earthquake tomography

    NASA Astrophysics Data System (ADS)

    Paulatto, M.; Laigle, M.; Charvis, P.; Galve, A.

    2015-12-01

    The degree of coupling and the seismogenic properties of the plate interface at subduction zones are affected by the abundance of slab fluids and subducted sediments. High fluid input can cause high pore-fluid pressures in the subduction channel and decrease coupling leading to aseismic behaviour. Constraining fluid input and transfer is therefore important for understanding plate coupling and large earthquake hazard, particularly in places where geodetic and seismological constraints are scarce. We use P-wave traveltimes from several active source seismic experiments and P- and S-wave traveltimes from shallow and intermediate depth (< 150 km) local earthquakes recorded on a vast amphibious array of OBSs and land stations to recover the Vp and Vp/Vs structure of the central Lesser Antilles subduction zone. Our model extends between Martinique and Antigua from the prism to the arc and from the surface to a depth of 160 km. We find low Vp and high Vp/Vs ratio (> 1.80) on the top of the slab, at depths of up to 100 km. We interpret this high Vp/Vs ratio anomaly as evidence of elevated fluid content either as free fluids or as bound fluids in hydrated minerals (e.g. serpentinite). The strength and depth extent of the anomaly varies strongly from south to north along the subduction zone and correlates with variations in forearc morphology and with sediment input constrained by multi-channel seismic reflection profiles. The anomaly is stronger and extends to greater depth in the south, offshore Martinique, where sediment input is elevated due to the vicinity of the Orinoco delta. The gently dipping forearc slope observed in this region may be the result of weak coupling of the plate interface. A high Vp/Vs ratio is also observed in the forearc likely indicating a fractured and water-saturated overriding plate. On the other hand the anomaly is weaker and shallower offshore Guadeloupe, where sediment input is low due to subduction of the Barracuda ridge. Here a strong

  19. Active control of noise on the source side of a partition to increase its sound isolation

    NASA Astrophysics Data System (ADS)

    Tarabini, Marco; Roure, Alain; Pinhede, Cedric

    2009-03-01

    This paper describes a local active noise control system that virtually increases the sound isolation of a dividing wall by means of a secondary source array. With the proposed method, sound pressure on the source side of the partition is reduced using an array of loudspeakers that generates destructive interference on the wall surface, where an array of error microphones is placed. The reduction of sound pressure on the incident side of the wall is expected to decrease the sound radiated into the contiguous room. The method efficiency was experimentally verified by checking the insertion loss of the active noise control system; in order to investigate the possibility of using a large number of actuators, a decentralized FXLMS control algorithm was used. Active control performances and stability were tested with different array configurations, loudspeaker directivities and enclosure characteristics (sound source position and absorption coefficient). The influence of all these parameters was investigated with the factorial design of experiments. The main outcome of the experimental campaign was that the insertion loss produced by the secondary source array, in the 50-300 Hz frequency range, was close to 10 dB. In addition, the analysis of variance showed that the active noise control performance can be optimized with a proper choice of the directional characteristics of the secondary source and the distance between loudspeakers and error microphones.

  20. Three-dimensional localization of low activity gamma-ray sources in real-time scenarios

    NASA Astrophysics Data System (ADS)

    Sharma, Manish K.; Alajo, Ayodeji B.; Lee, Hyoung K.

    2016-03-01

    Radioactive source localization plays an important role in tracking radiation threats in homeland security tasks. Its real-time application requires computationally efficient and reasonably accurate algorithms even with limited data to support detection with minimum uncertainty. This paper describes a statistic-based grid-refinement method for backtracing the position of a gamma-ray source in a three-dimensional domain in real-time. The developed algorithm used measurements from various known detector positions to localize the source. This algorithm is based on an inverse-square relationship between source intensity at a detector and the distance from the source to the detector. The domain discretization was developed and implemented in MATLAB. The algorithm was tested and verified from simulation results of an ideal case of a point source in non-attenuating medium. Subsequently, an experimental validation of the algorithm was performed to determine the suitability of deploying this scheme in real-time scenarios. Using the measurements from five known detector positions and for a measurement time of 3 min, the source position was estimated with an accuracy of approximately 53 cm. The accuracy improved and stabilized to approximately 25 cm for higher measurement times. It was concluded that the error in source localization was primarily due to detection uncertainties. In verification and experimental validation of the algorithm, the distance between 137Cs source and any detector position was between 0.84 m and 1.77 m. The results were also compared with the least squares method. Since the discretization algorithm was validated with a weak source, it is expected that it can localize the source of higher activity in real-time. It is believed that for the same physical placement of source and detectors, a source of approximate activity 0.61-0.92 mCi can be localized in real-time with 1 s of measurement time and same accuracy. The accuracy and computational efficiency

  1. Mantle dynamics and slab rheology constrained by numerical modeling, structural and source seismology

    NASA Astrophysics Data System (ADS)

    Alpert, Lisa Ann

    I use geodynamic models to increase our understanding of the fate of subducted lithosphere as it contributes and responds to surface plate motion and upper mantle flow, as well as its effect on surface processes, using various surface observables. In Chapter 2, I compare predicted stress tensors from mantle circulation models to centroid moment tensor solutions from seismic events in order to constrain to first order the strength of upper mantle slabs. I find that moderately strong slabs produce the best match to the observations and that the net rotation of the lithosphere with respect to the lower mantle is important in generating the global-scale asymmetry in intermediate depth deformation. Using the global constraints and mantle flow computations from Chapter 2, I focus on the western Mediterranean in Chapter 3, where earthquake patterns and seismic tomography are insufficient to precisely resolve the density structure beneath the Alboran Sea that is reflected in the complex surface tectonics. Here, I predict upper mantle anisotropy and SKS splitting resulting from the flow models for a range of suggested structures. I show that SKS splitting observations in the Alboran Sea region are best reproduced by mantle flow models that include a deeply extending, slab-like structure beneath the Alboran Sea, elongate along the Iberian margin from Granada to the Gibraltar arc, where it curves southward toward the High Atlas. I also find that the absolute reference frame choice when prescribing surface velocities is crucial due to the opposing surface flow orientation in this region between two end-member absolute plate motion models. The southwest-directed surface flow in the hot-spot reference frame (HS3), when combined with sublithospheric deflection in response to structure in the Alboran region, generates a north-south shear and NNW splitting orientations most similar to the patterns observed along Gibraltar, without invoking slab rollback. Along with seismicity, regional uplift patterns and magmatism have been used to infer the relationship between subducting slabs and surface processes. In Chapter 4, I develop three dimensional, thermochemical, dynamic subduction models guided by seismicity and geomorphology from the Banda arc to explore the fate of subducted slabs after continental collision. I confirm the importance of buoyancy contrasts in exerting a first order control on the generation of slab tears in the upper mantle. I find that rheology exerts a strong control on the timing of slab tearing while continental geomorphology may explain complex surface processes in regions of incipient continental collision. From my modeling, I infer that seismicity patterns beneath the Banda Arc represent a westward propagating slab tear in response to the collision of the buoyant Australian shelf, and an eastward propagating slab tear in response to the collision of the Scott Plateau to the west. Further utilization of surface observations along with continued advances in geodynamic modeling continue to bridge the gap between lithospheric and deeper mantle processes.

  2. Active Control of a Moving Noise SOURCE—EFFECT of Off-Axis Source Position

    NASA Astrophysics Data System (ADS)

    GUO, J.; PAN, J.; HODGSON, M.

    2002-03-01

    An optimally arranged multiple-channel active-control system is known to be able to create a large quiet zone in free space for a stationary primary noise source. When the primary noise source moves, the active control of the noise becomes much more difficult, as the primary noise field changes with time in space. In this case, the controller of the control system must respond fast enough to compensate for the change; much research has been focused on this issue. In this paper, it is shown that a moving source also causes difficulties from an acoustical perspective. A moving source not only changes continuously the strengths and phases of the sound field in the space, but also changes the wavefront of the primary sound field continuously. It is known that the efficiency of active noise control is determined mainly by the wavefront matching between the primary and control fields. To keep the control system effective in the case of a moving source, the wavefront of the control field needs to change, in order to continuously match the primary-wavefront change. This paper shows that there are limitations to the control-wavefront change. An optimally pre-arranged, multiple-channel control system is not able to construct a matching wavefront when the primary source moves outside a certain range. In other words, the control system is still able to create a large quiet zone only when the primary source moves within a range around the central axis of the control system. Both the location and the size of the quiet zone change with the location of the primary source.

  3. Studies on the nitrate reductase activities of the fruit and the source leaf in pepper

    SciTech Connect

    Achhireddy, N.R.; Beevers, L.; Fletcher, J.S.

    1983-12-01

    Nitrate reductase (NR) activity (NO/sub 2//sup -/ produced in the dark and under anaerobic conditions) of 30-day-old fruit of Capsicum annuum L. was 2.2% that in tissues of a single leaf adjacent to each fruit (33 vs. 1500 nmoles/hr-g fresh weight). The optimal NR activity in one source leaf could only account for about 17% of the fruit's total nitrogen accumulation, while the fruit's own NR activity was almost negligible. Covered and uncovered fruits did not differ significantly in NR activities. 19 references, 1 figure, 1 table.

  4. Complex active regions as the main source of extreme and large solar proton events

    NASA Astrophysics Data System (ADS)

    Ishkov, V. N.

    2013-12-01

    A study of solar proton sources indicated that solar flare events responsible for ≥2000 pfu proton fluxes mostly occur in complex active regions (CARs), i.e., in transition structures between active regions and activity complexes. Different classes of similar structures and their relation to solar proton events (SPEs) and evolution, depending on the origination conditions, are considered. Arguments in favor of the fact that sunspot groups with extreme dimensions are CARs are presented. An analysis of the flare activity in a CAR resulted in the detection of "physical" boundaries, which separate magnetic structures of the same polarity and are responsible for the independent development of each structure.

  5. New light sources and sensors for active optical 3D inspection

    NASA Astrophysics Data System (ADS)

    Osten, Wolfgang; Jueptner, Werner P. O.

    1999-11-01

    The implementation of active processing strategies in optical 3D-inspection needs the availability of flexible hardware solutions. The system components illumination and sensor/detector are actively involved in the processing chain by a feedback loop that is controlled by the evaluation process. Therefore this article deals with new light sources and sensor which appeared recently on the market and can be applied successfully for the implementation of active processing principles. Some applications where such new components are used to implement an active measurement strategy are presented.

  6. The New Seismological Observation System in Chile and a Real time GPS Detection of the Displacement Associated with a M=7.7 Earthquake in Chile

    NASA Astrophysics Data System (ADS)

    Barrientos, S. E.

    2014-12-01

    Due to the occurrence of several high-impact earthquakes in Chile within the last few years, governmental authorities decided to improve the seismic monitoring capabilities in the country. Along these lines, in 2013 the University of Chile created the National Seismological Center, an agency that is the continuation of the Seismological Service. The Seismological Center at the University of Chile has been charged with the installation and robust operation of a network which includes three types of observations: acceleration, velocity and displacement. The complete observational system is based on the University´s backbone of more than 60 BB and strong motion instruments which include international collaborations with GeoForschungsZentrum (GFZ, Germany), Institut de Physique du Globe de Paris (IPGP, France) and Incorporated Research Institutions for Seismology (IRIS, USA). To this, 65 broadband, 65 strong-motion and 130 real-time dual-frequency GPS devices are being installed to complement the observational system. Additionally, 297 accelerometers distributed throughout the country will be connected to the main acquisition, processing and distribution system, which is also being upgraded by incorporating hardware virtualization capabilities. It is expected that most of the installation of the remote sensors is completed by the end of 2015. The GPS instruments will be deployed mainly along the coast every 40 or 50 km. Because a robust real-time communication is mandatory from each remote site, the preferred solution is radio link to concentration nodes where the signals (NMEA, including RTX, as well as other protocols such a BINEX, RCTM) can be uploaded to microwaves links or Vsat. Thirty one GPS stations have been deployed in the country, we expect to complete 30more installations this year. As a result of a trial experiment with RTX capabilities (clock and satellite corrections distributed via satellite) coastal horizontal displacements of up to 30 cm were

  7. Sources and magnitude of variability in pedometer-determined physical activity levels of youth

    PubMed Central

    Kim, So-Yeun; Park, Hye-Sang

    2015-01-01

    This study examined sources of variability in habitual physical activity of children, and the minimum number of days required for estimating children’s habitual physical activity levels using pedometers. A total of 31 children wore two pedometers during five weekdays and four weekend days. A two random facet completely crossed design was conducted with two-way analysis of variances across weekdays, weekends, and weekdays and weekend days combined. Moderate/high generalizability coefficients were estimated across all days. Primary sources of variability were variance components of the person and person by day interaction. Minimum numbers of days required for estimating habitual physical activity levels using a pedometer were five during weekdays. However, estimating habitual physical activity levels during weekends, and weekdays and weekend days combined was impractical. PMID:26730388

  8. Activation process in excitable systems with multiple noise sources: One and two interacting units.

    PubMed

    Franović, Igor; Todorović, Kristina; Perc, Matjaž; Vasović, Nebojša; Burić, Nikola

    2015-12-01

    We consider the coaction of two distinct noise sources on the activation process of a single excitable unit and two interacting excitable units, which are mathematically described by the Fitzhugh-Nagumo equations. We determine the most probable activation paths around which the corresponding stochastic trajectories are clustered. The key point lies in introducing appropriate boundary conditions that are relevant for a class II excitable unit, which can be immediately generalized also to scenarios involving two coupled units. We analyze the effects of the two noise sources on the statistical features of the activation process, in particular demonstrating how these are modified due to the linear or nonlinear form of interactions. Universal properties of the activation process are qualitatively discussed in the light of a stochastic bifurcation that underlies the transition from a stochastically stable fixed point to continuous oscillations. PMID:26764778

  9. Volcanic unrest leading to the July-August 2001 lateral eruption at Mt. Etna: Seismological constraints

    NASA Astrophysics Data System (ADS)

    Sicali, Simona; Barberi, Graziella; Cocina, Ornella; Musumeci, Carla; Patanè, Domenico

    2015-10-01

    mid-level volcanic plumbing system by ascending magma and precursory local stress field reorientations, demonstrating that seismological analysis can be used to detect subtle local stress changes that herald eruptive activity.

  10. Implementing the EPOS Thematic Core Services for Seismology - EPOS-S

    NASA Astrophysics Data System (ADS)

    Haslinger, Florian

    2014-05-01

    During the EPOS Preparatory Phase (2010-2014) the European community of seismological data and service providers prepared an implementation and development plan for the EPOS Thematic Core Services for Seismology, EPOS-S. Building upon the existing seismological service infrastructures in Europe and a long history of multilateral infrastructure development projects, EPOS-S organizes the services handling data, data products, tools, and software in four pillars: "Waveform Data", "Earthquake Products", "Seismic Hazard and Risk", and "Computational Seismology". The first pillar encompasses continuous and event-based waveforms, metadata from permanent and temporary stations, but also includes historical waveforms; an increased distribution of strong-motion data is envisioned. The second pillar "Earthquake Products" includes for example earthquake bulletins and catalogues and moment tensor solutions, but also other earthquake products not yet routinely distributed such as finite-fault models, or shake maps. The third pillar "Seismic Hazard and Risk" envisions the distribution of hazard relevant products: obviously seismic hazard maps but also fault databases, and ground motion prediction relations for different areas. "Computational Seismology" finally deals with massive data applications including the challenges of data staging but also with the development of tools, standard and distribution mechanisms for research products such as large tomographic models. In addition, an "e-seismology and common services" component will be formed in order to serve the more basic visualization, discovery and access portal functions across EPOS-S, closely integrated with the EPOS Integrated Core Services. This component will also provide a framework for expert groups and standards bodies (e.g. on community specific data or metadata formats, procedures and guidelines, or agreed methods for specific products). The implementation and development plan establishes a roadmap for the

  11. Influence of source composition and particle energy on the determination of gross alpha activity.

    PubMed

    Timón, A Fernández; Vargas, M Jurado; Sánchez, A B Ruano; Pérez, J de la Torre; Sánchez, A Martín

    2013-12-01

    The influence of different source compositions and α-particle energies on the detection efficiency of a gas-flow proportional counter was examined using experimental measurements and Monte Carlo simulations. Efficiency variation with alpha-particle energy was very marked, being less significant with the substrate composition. These results show that the determination of gross alpha activity in an unknown sample must be carried out very carefully in order to give a correct estimation of its activity. PMID:24184741

  12. Advanced Control Strategy for Single-Phase Voltage-Source Active Rectifier with Low Harmonic Emission

    NASA Astrophysics Data System (ADS)

    Blahník, Vojtĕch; Peroutka, Zdenĕk; Talla, Jakub

    2014-03-01

    This paper introduces the advanced control of single-phase voltage-source active rectifier. This control provide direct control of trolley-wire current and active damping of low-frequency disturbances at the converter ac side. Our proposed control strategy combines PR controller with feed-forward model and low-frequency harmonic compensator based on resonant controllers. Achieved experimental results show excellent converter behavior, where converter is fed by strongly distorted supply voltage.

  13. Efficient localization of synchronous EEG source activities using a modified RAP-MUSIC algorithm.

    PubMed

    Liu, Hesheng; Schimpf, Paul H

    2006-04-01

    Synchronization across different brain regions is suggested to be a possible mechanism for functional integration. Noninvasive analysis of the synchronization among cortical areas is possible if the electrical sources can be estimated by solving the electroencephalography inverse problem. Among various inverse algorithms, spatio-temporal dipole fitting methods such as RAP-MUSIC and R-MUSIC have demonstrated superior ability in the localization of a restricted number of independent sources, and also have the ability to reliably reproduce temporal waveforms. However, these algorithms experience difficulty in reconstructing multiple correlated sources. Accurate reconstruction of correlated brain activities is critical in synchronization analysis. In this study, we modified the well-known inverse algorithm RAP-MUSIC to a multistage process which analyzes the correlation of candidate sources and searches for independent topographies (ITs) among precorrelated groups. Comparative studies were carried out on both simulated data and clinical seizure data. The results demonstrated superior performance with the modified algorithm compared to the original RAP-MUSIC in recovering synchronous sources and localizing the epileptiform activity. The modified RAP-MUSIC algorithm, thus, has potential in neurological applications involving significant synchronous brain activities. PMID:16602571

  14. Seismological Analyses of the March 11, 2010, Pichilemu, Chile Mw 7.0 and Mw 6.9 Earthquakes

    NASA Astrophysics Data System (ADS)

    Ruiz-Paredes, J. A.; Hayes, G. P.; Socquet, A.; Carrizo, D.; Kanamori, H.

    2012-12-01

    On March 11, 2010, a sequence of large, shallow continental crust earthquakes shook Central Chile. Two normal faulting events, having magnitudes Mw 7.0 and Mw 6.9, were separated by just 15 minutes, with epicenters located near the town of Pichilemu. These kinds of large intraplate inland crustal earthquake are rare above the Chilean subduction zone, and it is important to better understand their relationship with the 27 February 2010, Mw 8.8, Maule earthquake. We present a broad seismological analysis of these earthquakes by using both teleseismic and regional data. We compute seismic moment tensors of both events via a W-Phase inversion, and test sensitivities to various inversion parameters in order to assess the stability of the solutions. The first event, at 14h 39m GMT, is well constrained, displaying a fault plane with strike of N145E, and a preferred dip angle of 55SW, consistent with the trend of aftershock locations. Teleseismic finite-fault inversions for this event show a large slip zone along the southern part of the fault, correlating well with the spatial density of aftershocks reported. The second shock (14h 55 GMT) appears to have ruptured a fault branching southward from the previous ruptured fault, within the hanging wall of the first event. Modeling seismograms at regional to teleseismic distances (Δ > 5°) is quite challenging because the observed seismic wave fields of both events overlap, increasing apparent complexity for the second event. We perform both point- and extended source inversions at regional and teleseismic distances, assessing sensitivity by analyzing changes in RMS misfits as a result of variations in fault orientation, dimension, and hypocenter location. Results show that the focal mechanism for the second event features a steeper dip angle and a strike rotated slightly clockwise with respect to the previous event. This kind of geological fault configuration, with secondary rupture in the hanging wall of a large normal fault

  15. ALLStars: Overcoming Multi-Survey Selection Bias using Crowd-Sourced Active Learning

    NASA Astrophysics Data System (ADS)

    Starr, D. L.; Richards, J. W.; Brink, H.; Miller, A. A.; Bloom, J. S.; Butler, N. R.; James, J. B.; Long, J. P.

    2012-09-01

    Developing a multi-survey time-series classifier presents several challenges. One problem is overcoming the sample selection bias which arises when the instruments or observing cadences differ between the training and testing datasets. In this case, the probabilistic distributions characterizing the sources in the training survey dataset differ from the source distributions in the other survey, resulting in poor results when a classifier is naively applied. To resolve this, we have developed the ALLStars active learning framework which allows us to bootstrap a classifier onto a new survey using a small set of optimally chosen sources which are then presented to users for manual classification. Several iterations of this crowd-sourcing process results in a significantly improved classifier. Using this procedure, we have built a variable star light-curve classifier using OGLE, Hipparcos, and ASAS survey data.

  16. The Main Sources of Intersubject Variability in Neuronal Activation for Reading Aloud

    ERIC Educational Resources Information Center

    Kherif, Ferath; Josse, Goulven; Seghier, Mohamed L.; Price, Cathy J.

    2009-01-01

    The aim of this study was to find the most prominent source of intersubject variability in neuronal activation for reading familiar words aloud. To this end, we collected functional imaging data from a large sample of subjects (n = 76) with different demographic characteristics such as handedness, sex, and age, while reading. The…

  17. 1994 Activity Report, National Synchrotron Light Source. Annual report, October 1, 1993-September 30, 1994

    SciTech Connect

    Rothman, E.Z.

    1995-05-01

    This report is a summary of activities carried out at the National Synchrotron Light Source during 1994. It consists of sections which summarize the work carried out in differing scientific disciplines, meetings and workshops, operations experience of the facility, projects undertaken for upgrades, administrative reports, and collections of abstracts and publications generated from work done at the facility.

  18. Measuring the activity of a 51Cr neutrino source based on the gamma-radiation spectrum

    NASA Astrophysics Data System (ADS)

    Gorbachev, V. V.; Gavrin, V. N.; Ibragimova, T. V.; Kalikhov, A. V.; Malyshkin, Yu. M.; Shikhin, A. A.

    2015-12-01

    A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of 51Cr is presented.

  19. Promoting Conceptual Change through Active Learning Using Open Source Software for Physics Simulations

    ERIC Educational Resources Information Center

    Baser, Mustafa

    2006-01-01

    This paper reports upon an active learning approach that promotes conceptual change when studying direct current electricity circuits, using free open source software, "Qucs". The study involved a total of 102 prospective mathematics teacher students. Prior to instruction, students' understanding of direct current electricity was determined by a…

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

    NASA Astrophysics Data System (ADS)

    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

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

    NASA Astrophysics Data System (ADS)

    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

  2. Accumulated source imaging of brain activity with both low and high-frequency neuromagnetic signals

    PubMed Central

    Xiang, Jing; Luo, Qian; Kotecha, Rupesh; Korman, Abraham; Zhang, Fawen; Luo, Huan; Fujiwara, Hisako; Hemasilpin, Nat; Rose, Douglas F.

    2014-01-01

    Recent studies have revealed the importance of high-frequency brain signals (>70 Hz). One challenge of high-frequency signal analysis is that the size of time-frequency representation of high-frequency brain signals could be larger than 1 terabytes (TB), which is beyond the upper limits of a typical computer workstation's memory (<196 GB). The aim of the present study is to develop a new method to provide greater sensitivity in detecting high-frequency magnetoencephalography (MEG) signals in a single automated and versatile interface, rather than the more traditional, time-intensive visual inspection methods, which may take up to several days. To address the aim, we developed a new method, accumulated source imaging, defined as the volumetric summation of source activity over a period of time. This method analyzes signals in both low- (1~70 Hz) and high-frequency (70~200 Hz) ranges at source levels. To extract meaningful information from MEG signals at sensor space, the signals were decomposed to channel-cross-channel matrix (CxC) representing the spatiotemporal patterns of every possible sensor-pair. A new algorithm was developed and tested by calculating the optimal CxC and source location-orientation weights for volumetric source imaging, thereby minimizing multi-source interference and reducing computational cost. The new method was implemented in C/C++ and tested with MEG data recorded from clinical epilepsy patients. The results of experimental data demonstrated that accumulated source imaging could effectively summarize and visualize MEG recordings within 12.7 h by using approximately 10 GB of computer memory. In contrast to the conventional method of visually identifying multi-frequency epileptic activities that traditionally took 2–3 days and used 1–2 TB storage, the new approach can quantify epileptic abnormalities in both low- and high-frequency ranges at source levels, using much less time and computer memory. PMID:24904402

  3. Contributions to Proceedings from the NATO Advanced Research Workshop on the Seismology of the Sun and the Distant Stars

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Advanced research results on the seismology of the Sun and distant stars is presented. Topics presented include: (1) detection of global convective wave flows; (2) observation of low degree p-mode oscillations; and (3) techniques for spectral deconvolution.

  4. Building the European Seismological Research Infrastructure: results from 4 years NERIES EC project

    NASA Astrophysics Data System (ADS)

    van Eck, T.; Giardini, D.

    2010-12-01

    The EC Research Infrastructure (RI) project, Network of Research Infrastructures for European Seismology (NERIES), implemented a comprehensive European integrated RI for earthquake seismological data that is scalable and sustainable. NERIES opened a significant amount of additional seismological data, integrated different distributed data archives, implemented and produced advanced analysis tools and advanced software packages and tools. A single seismic data portal provides a single access point and overview for European seismological data available for the earth science research community. Additional data access tools and sites have been implemented to meet user and robustness requirements, notably those at the EMSC and ORFEUS. The datasets compiled in NERIES and available through the portal include among others: - The expanded Virtual European Broadband Seismic Network (VEBSN) with real-time access to more then 500 stations from > 53 observatories. This data is continuously monitored, quality controlled and archived in the European Integrated Distributed waveform Archive (EIDA). - A unique integration of acceleration datasets from seven networks in seven European or associated countries centrally accessible in a homogeneous format, thus forming the core comprehensive European acceleration database. Standardized parameter analysis and actual software are included in the database. - A Distributed Archive of Historical Earthquake Data (AHEAD) for research purposes, containing among others a comprehensive European Macroseismic Database and Earthquake Catalogue (1000 - 1963, M ≥5.8), including analysis tools. - Data from 3 one year OBS deployments at three sites, Atlantic, Ionian and Ligurian Sea within the general SEED format, thus creating the core integrated data base for ocean, sea and land based seismological observatories. Tools to facilitate analysis and data mining of the RI datasets are: - A comprehensive set of European seismological velocity reference

  5. PUTTING CORONAL SEISMOLOGY ESTIMATES OF THE MAGNETIC FIELD STRENGTH TO THE TEST

    SciTech Connect

    De Moortel, I.; Pascoe, D. J.

    2009-07-10

    The magnetic field strength inside a model coronal loop is 'estimated' using coronal seismology, to examine the reliability of magnetic field strengths derived from observed, transverse coronal loop oscillations. Three-dimensional numerical simulations of the interaction of an external pressure pulse with a coronal loop (modeled as a three-dimensional density enhancement inside a two-dimensional magnetic arcade) are analyzed and the 'observed' properties of the excited transverse loop oscillations are used to derive the value of the local magnetic field strength, following the method of Nakariakov and Ofman. Due to the (unexpected) change in periodicity, the magnetic field derived from our 'observed' oscillation is substantially different from the actual (input) magnetic field value (approximately 50%). Coronal seismology can derive useful information about the local magnetic field, but the combined effect of the loop curvature, the density ratio, and aspect ratio of the loop appears to be more important than previously expected.

  6. Coronal loop seismology using damping of standing kink oscillations by mode coupling

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    Context. Kink oscillations of solar coronal loops are frequently observed to be strongly damped. The damping can be explained by mode coupling on the condition that loops have a finite inhomogeneous layer between the higher density core and lower density background. The damping rate depends on the loop density contrast ratio and inhomogeneous layer width. Aims: The theoretical description for mode coupling of kink waves has been extended to include the initial Gaussian damping regime in addition to the exponential asymptotic state. Observation of these damping regimes would provide information about the structuring of the coronal loop and so provide a seismological tool. Methods: We consider three examples of standing kink oscillations observed by the Atmospheric Imaging Assembly (AIA) of the Solar Dynamics Observatory (SDO) for which the general damping profile (Gaussian and exponential regimes) can be fitted. Determining the Gaussian and exponential damping times allows us to perform seismological inversions for the loop density contrast ratio and the inhomogeneous layer width normalised to the loop radius. The layer width and loop minor radius are found separately by comparing the observed loop intensity profile with forward modelling based on our seismological results. Results: The seismological method which allows the density contrast ratio and inhomogeneous layer width to be simultaneously determined from the kink mode damping profile has been applied to observational data for the first time. This allows the internal and external Alfvén speeds to be calculated, and estimates for the magnetic field strength can be dramatically improved using the given plasma density. Conclusions: The kink mode damping rate can be used as a powerful diagnostic tool to determine the coronal loop density profile. This information can be used for further calculations such as the magnetic field strength or phase mixing rate.

  7. Seismological research requirements for a comprehensive test-ban monitoring system

    SciTech Connect

    1995-12-31

    This book covers: (1) the desirable characteristics and capabilities of seismic monitoring stations; (2) recommendations on the flow paths and handling of the data, which are to be unclassified; and (3) the types and extent of research that will be needed in the next decade. The primary focus of the book is to explore how basic seismological research and test ban monitoring can be mutually beneficial.

  8. Shear bond strength to enamel after power bleaching activated by different sources.

    PubMed

    Can-Karabulut, Deniz C; Karabulut, Baris

    2010-01-01

    The purpose of the present study was to evaluate enamel bond strength of a composite resin material after hydrogen peroxide bleaching, activated by a diode laser (LaserSmile), an ozone device (HealOzone), a light-emitting diode (BT Cool whitening system), and a quartz-Plus. Fifty extracted caries-free permanent incisors were used in this study. Thirty-eight percent hydrogen peroxidegel was applied to sound, flattened labial enamel surfaces and activated by different sources. Enamel surfaces that had received no treatment were used as control samples. Bonding agent was applied according to the manufacturer's instructions and the adhesion test was performed according to ISO/TS 11405. Statistical analysis showed significant influence of the different activation technique of hydrogen peroxide on shear bond strength to enamel (ANOVA, LSD, P < 0.05). The data in this vitro explorative study suggest the activation of hydrogen peroxide by different sources may further affect the shear bond strength of subsequent composite resin restoration to enamel. Within the limitations of this in vitro study, further studies examining the structural changes of activated hydrogen peroxide-treated enamel are needed. Due to the different activation methods; duration of light irradiation effects, longer time periods may be needed before application of adhesive restorations to enamel, compared with non-activated bleaching. PMID:21069109

  9. Nitrogen source activates TOR (target of rapamycin) complex 1 via glutamine and independently of Gtr/Rag proteins.

    PubMed

    Stracka, Daniele; Jozefczuk, Szymon; Rudroff, Florian; Sauer, Uwe; Hall, Michael N

    2014-09-01

    The evolutionary conserved TOR complex 1 (TORC1) activates cell growth in response to nutrients. In yeast, TORC1 responds to the nitrogen source via a poorly understood mechanism. Leucine, and perhaps other amino acids, activates TORC1 via the small GTPases Gtr1 and Gtr2, orthologs of the mammalian Rag GTPases. Here we investigate the activation of TORC1 by the nitrogen source and how this might be related to TORC1 activation by Gtr/Rag. The quality of the nitrogen source, as defined by its ability to promote growth and glutamine accumulation, directly correlates with its ability to activate TORC1 as measured by Sch9 phosphorylation. Preferred nitrogen sources stimulate rapid, sustained Sch9 phosphorylation and glutamine accumulation. Inhibition of glutamine synthesis reduces TORC1 activity and growth. Poor nitrogen sources stimulate rapid but transient Sch9 phosphorylation. A Gtr1 deficiency prevents the transient stimulation of TORC1 but does not affect the sustained TORC1 activity in response to good nitrogen sources. These findings suggest that the nitrogen source must be converted to glutamine, the preferred nitrogen source in yeast, to sustain TORC1 activity. Furthermore, sustained TORC1 activity is independent of Gtr/Rag. Thus, the nitrogen source and Gtr/Rag activate TORC1 via different mechanisms. PMID:25063813

  10. A novel method for active fissile mass estimation with a pulsed neutron source

    NASA Astrophysics Data System (ADS)

    Dubi, C.; Ridnik, T.; Israelashvili, I.; Pedersen, B.

    2013-07-01

    Neutron interrogation facilities for mass evaluation of Special Nuclear Materials (SNM) samples are divided into two main categories: passive interrogation, where all neutron detections are due to spontaneous events, and active interrogation, where fissions are induced on the tested material by an external neutron source. While active methods are, in general, faster and more effective, their analysis is much harder to carry out. In the paper, we will introduce a new formalism for analyzing the detection signal generated by a pulsed source active interrogation facility. The analysis is aimed to distinct between fission neutrons from the main neutron source in the system, and the surrounding "neutron noise". In particular, we derive analytic expressions for the first three central moments of the number of detections in a given time interval, in terms of the different neutron sources. While the method depends on exactly the same physical assumptions as known models, the simplicity of the suggested formalism allows us to take into account the variance of the external neutron source—an effect that was so far neglected.

  11. Atmospheric Seismology on Mars with InSight

    NASA Astrophysics Data System (ADS)

    Rolland, L. M.; Larmat, C. S.; Remillieux, M.; Karakostas, F. G.; Dessa, J. X.; Garcia, R.; Lognonne, P. H.

    2015-12-01

    InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) is a NASA Discovery Program mission that will place a single geophysical lander on Mars to study its deep interior. This mission is planned to be launched in March 2016, with first data return expected by the end of the year. Meteorological sensors onboard the lander will provide a continuous dataset of pressure, air temperature and wind speed and direction. The unprecedented sensitivity of the pressure sensor should allow catching signatures of a breath of infrasound sources from bolides to dust devils. In this presentation, we will show how acoustic and gravity waves propagation in the atmosphere of Mars, that is not only much more tenuous (~ 6 mbar) than the Earth atmosphere but also CO2-rich and extremely windy. This demonstration will make use of acoustic ray tracing through an atmosphere modeled using the Mars Global Reference Atmospheric Model (MarsGram-2010) and also of the Spectral Element Method and normal modes summation for cross-benchmarking. In particular, the latter method allows the integration of dissipation processes due to viscosity and CO2 relaxation. We will evaluate the maturity of the diverse numerical tools to model real Earth data, selected among ionospheric observations of chemical surface explosions, volcano eruptions and earthquakes. Eventually, we will investigate the efficiency of potential external sources to excite seismic waves to be sensed by the Insight seismometer SEIS and thus illuminating the interior of the planet.

  12. A combined crustal depth model for Iran based on the gravity and seismological data

    NASA Astrophysics Data System (ADS)

    Kiamehr, Ramin

    2010-05-01

    The inversion of the Bouguer gravity data based on the Parker-Oldenburg method is the well-known method for estimation of the Moho depth model between geoscientist. The advantage of this method is that it gives a continuous surface model in the study area. However, in order to have a precise result in this method, we need to have a well distributed and dense gravity data which does not have large systematic errors. Estimation of the crust depth based on the seismological data is another independent method which is basically point-wised but more precise than the inversion approach. In order to reduce the effect of datum and systematic errors in inversion and taking advantage of the precise seismological model, we developed a combined crustal model for Iran based on the corrective surface idea. The four, five and seven parameters models were used in the least-squares sense to get the best combination. The combined model evaluated based on the independent seismological data. The results indicate clearly very good improvements versus the gravity inversion method.

  13. fMRI activation patterns in an analytic reasoning task: consistency with EEG source localization

    NASA Astrophysics Data System (ADS)

    Li, Bian; Vasanta, Kalyana C.; O'Boyle, Michael; Baker, Mary C.; Nutter, Brian; Mitra, Sunanda

    2010-03-01

    Functional magnetic resonance imaging (fMRI) is used to model brain activation patterns associated with various perceptual and cognitive processes as reflected by the hemodynamic (BOLD) response. While many sensory and motor tasks are associated with relatively simple activation patterns in localized regions, higher-order cognitive tasks may produce activity in many different brain areas involving complex neural circuitry. We applied a recently proposed probabilistic independent component analysis technique (PICA) to determine the true dimensionality of the fMRI data and used EEG localization to identify the common activated patterns (mapped as Brodmann areas) associated with a complex cognitive task like analytic reasoning. Our preliminary study suggests that a hybrid GLM/PICA analysis may reveal additional regions of activation (beyond simple GLM) that are consistent with electroencephalography (EEG) source localization patterns.

  14. Seismological studies of tectonics in the Toba region and in the Banda sea, Indonesia

    NASA Astrophysics Data System (ADS)

    Fauzi

    By using arrival time data from the Indonesian Meteorological and Geophysical Agency (MGA), International Seismological Center (ISC) and United State Geological Survey (USGS), and the Centroid Moment Tensor (CMT) solutions of Harvard, I studied the tectonic features in north Sumatra and Banda arc, Indonesia. In north Sumatra, the study was focused on the subducted slab and attenuation beneath Toba---the world's largest Quaternary caldera. In the Banda arc, I studied the unusual shape of the slab where a part of Australian continent has been subducted under the oceanic plate. Toba was formed 75ka, resulting in a caldera of the area of 25km x 100km. The age and area of the caldera suggest that the magma remains partially molten. Seismograms at the stations near the caldera showed that P- and S-waves have been attenuated. This attenuation was studied using both qualitative and quantitative method to locate the magma system. By applying both methods, the results indicate that the magma chamber is shallower than 20km. In Banda area, hypocenters were determined using a combination of local and teleseismic data to reveal the slab geometry. Because a flat-lying slab at 600km depth is unusual, the accuracy of the hypocenters within this slab was studied in more detail. Statistically several hypocenters in this region have been accurately located using probability density functions. The shape of the slab shown by the hypocenter distribution reveals high contortion beneath the Banda sea. The stress distribution revealed from the P,T and B axes of fault plane solutions suggests that the stress field is controlled by both gravity and contortion within the slab. The subduction process in Banda region has changed since the Australian continent plate collided with the Banda arc. Strike slip earthquakes seem to concentrate along the extension of the Terera-Aiduna fault to the southwest in Wetar backarc thrust. I conclude that the extension of Terera-Aiduna fault in the subducted

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

    NASA Astrophysics Data System (ADS)

    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

  16. Investigating effectiveness of activated carbons of natural sources on various supercapacitors

    NASA Astrophysics Data System (ADS)

    Faisal, Md. Shahnewaz Sabit; Rahman, Muhammad M.; Asmatulu, Ramazan

    2016-04-01

    Activated carbon can be produced from natural sources, such as pistachio and acorn shells, which can be an inexpensive and sustainable sources of natural wastes for the energy storage devices, such as supercapacitors. The carbonaceous materials used in this study were carbonized at the temperatures of 700°C and 900°C after the stabilization process at 240°C for two hours. These shells showed approximately 60% carbon yield. Carbonized nutshells were chemically activated using1wt% potassium hydroxide (KOH). Activated carbon powders with polyvinylidene fluoride (PVdF) were used to construct carbon electrodes. A 1M of tetraethylammonium tetrafluoroborate (TEABF4) and propylene carbonate (PC) were used as electrolytes. Electrochemical techniques, such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characterization of the supercapacitors. Scanning electron microscopy (SEM) was used to inspect the surface texture of the activated carbons. Activated pistachio shells carbonized at 700°C showed more porous surface texture than those carbonized at 900°C. Effects of the carbonization temperatures were studied for their electrochemical characteristics. The shells carbonized at 700°C showed better electrochemical characteristics compared to those carbonized at 900°C. The test results provided about 27,083 μF/g specific capacitance at a scan rate of 10mV/s. This study showed promising results for using these activated carbons produced from the natural wastes for supercapacitor applications.

  17. Effect of source-separated urine storage on estrogenic activity detected using bioluminescent yeast Saccharomyces cerevisiae.

    PubMed

    Jaatinen, Sanna; Kivistö, Anniina; Palmroth, Marja R T; Karp, Matti

    2016-09-01

    The objective was to demonstrate that a microbial whole cell biosensor, bioluminescent yeast, Saccharomyces cerevisiae (BMAEREluc/ERα) can be applied to detect overall estrogenic activity from fresh and stored human urine. The use of source-separated urine in agriculture removes a human originated estrogen source from wastewater influents, subsequently enabling nutrient recycling. Estrogenic activity in urine should be diminished prior to urine usage in agriculture in order to prevent its migration to soil. A storage period of 6 months is required for hygienic reasons; therefore, estrogenic activity monitoring is of interest. The method measured cumulative female hormone-like activity. Calibration curves were prepared for estrone, 17β-estradiol, 17α- ethinylestradiol and estriol. Estrogen concentrations of 0.29-29,640 μg L(-1) were detectable while limit of detection corresponded to 0.28-35 μg L(-1) of estrogens. The yeast sensor responded well to fresh and stored urine and gave high signals corresponding to 0.38-3,804 μg L(-1) of estrogens in different urine samples. Estrogenic activity decreased during storage, but was still higher than in fresh urine implying insufficient storage length. The biosensor was suitable for monitoring hormonal activity in urine and can be used in screening anthropogenic estrogen-like compounds interacting with the receptor. PMID:26804108

  18. A new activated primary tank developed for recovering carbon source and its application.

    PubMed

    Jin, Pengkang; Wang, Xianbao; Zhang, Qionghua; Wang, Xiaochang; Ngo, Huu Hao; Yang, Lei

    2016-01-01

    A novel activated primary tank process (APT) was developed for recovering carbon source by fermentation and elutriation of primary sludge. The effects of solids retention time (SRT), elutriation intensity (G) and return sludge ratio (RSR) on this recovery were evaluated in a pilot scale reactor. Results indicated that SRT significantly influenced carbon source recovery, and mechanical elutriation could promote soluble COD (SCOD) and VFA yields. The optimal conditions of APT were SRT=5d, G=152s(-1) and RSR=10%, SCOD and VFA production were 57.0mg/L and 21.7mg/L. Particulate organic matter in sludge was converted into SCOD and VFAs as fermentative bacteria were significantly enriched in APT. Moreover, the APT process was applied in a wastewater treatment plant to solve the problem of insufficient carbon source. The outcomes demonstrated that influent SCOD of biological tank increased by 31.1%, which improved the efficiency of removing nitrogen and phosphorus. PMID:26562688

  19. Integrating distributed data archives in seismology: the European Integrated waveform Data Archives (EIDA)

    NASA Astrophysics Data System (ADS)

    Sleeman, Reinoud; Hanka, Winfried; Clinton, John; van Eck, Torild; Trani, Luca

    2013-04-01

    ORFEUS is the non-profit foundation that coordinates and promotes digital broadband seismology in Europe. Since 1987 the ORFEUS Data Center (ODC) has been its jointly funded data center. However, within the last decade we have seen an exponential growth of high quality digital waveform data relevant for seismological and general geoscience research. In addition to the rapid expansion in number and density of broadband seismic networks this growth is fuelled by data collected from other sensor types (strong motion, short period) and deployment types (aftershock arrays, temporary field campaigns, OBS). As a consequence, ORFEUS revised its data archiving infrastructure and organization, a major component of this is the formal establishment of the European Integrated waveform Data Archives (EIDA). Within the NERIES and NERA EC projects GFZ has taken the lead in developing ArcLink as a tool to provide uniform access to distributed seismological waveform data archives. The new suite of software and services provides the technical basis of EIDA. To ensure that those developments will become sustainable, an EIDA group has been formed within ORFEUS. This founding group of EIDA nodes, formed in 2013, will be responsible for steering and maintaining the technical developments and organization of an effective operational distributed waveform data archive for seismology in Europe. The EIDA Founding nodes are: ODC/ORFEUS, GEOFON/GFZ/Germany, SED/Switzerland, RESIF/CNRS-INSU/France, INGV/Italy and BGR/Germany. These represent EIDA nodes that have committed themselves within ORFEUS to manage EIDA, that is, to maintain and develop EIDA into a stable sustainable research infrastructure. This task involves a number of challenges with regard to quality and metadata maintenance, but also to provide efficient and uncomplicated data access for users. This also includes effective global archive synchronization with developments within the International Federation of Digital Seismograph

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

    NASA Astrophysics Data System (ADS)

    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

  1. Seismological analysis of the fourth North Korean nuclear test

    NASA Astrophysics Data System (ADS)

    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

  2. Low-Frequency Sound Field Control in a Reverberant Room with a Single Active Controller Source.

    NASA Astrophysics Data System (ADS)

    Bullock, John Drayton, Jr.

    The operation of a single active controller source in a reverberant room has been investigated. The system consists of a controlled transducer source and a near-source microphone, with electronics arranged as a closed feedback loop. The controller system responds to a single source placed arbitrarily in the room. A theoretical analysis is presented based on the two port model of the controller transducer interfaced to an equivalent description of the reverberant room. The room acoustic transfer impedances between the active controller, room exciter source, near controller pressure sensor, and an arbitrary point in the reverberant sound field are described by a Green's function model. To minimize resonant effects of the controller piston diaphragm, a second control feedback loop using a diaphragm mounted accelerometer was added to the pressure control loop. Examples of the controller system operation were drawn from a computer model. Experimental data were gathered in a test reverberation room at the Applied Research Laboratory of The Pennsylvania State University. This investigation has brought forth three factors which define the limits on wide band control loop gain. They are (i) the position of an accelerometer on the controller diaphragm, (ii) the spacing between the controller and pressure sensor microphone, and (iii) the first mode frequency and the Q of the controller diaphragm. These system and transducer constraints can introduce instability in the control system. The controller system operation in the room has been modeled as a lumped element ideal piston using a flow graph representation. Additional loops on the graph are used to represent non-ideal transducer aberrations, and to define the pressure at various points in the room. Four cases for controller operation have been defined based on the proximity of the room source, the pressure sensor, and the controller. Two of these are important for practical applications: (i) the sensor microphone and

  3. Applicability of light-emitting diodes as light sources for active differential optical absorption spectroscopy measurements.

    PubMed

    Kern, Christoph; Trick, Sebastian; Rippel, Bernhard; Platt, Ulrich

    2006-03-20

    We present what is to our knowledge the first use of light-emitting diodes (LEDs) as light sources for long-path differential optical absorption spectroscopy (LP-DOAS) measurements of trace gases in the open atmosphere. Modern LEDs represent a potentially advantageous alternative to thermal light sources, in particular to xenon arc lamps, which are the most common active DOAS light sources. The radiative properties of a variety of LEDs were characterized, and parameters such as spectral shape, spectral range, spectral stability, and ways in which they can be influenced by environmental factors were analyzed. The spectra of several LEDs were found to contain Fabry-Perot etalon-induced spectral structures that interfered with the DOAS evaluation, in particular when a constant temperature was not maintained. It was shown that LEDs can be used successfully as light sources in active DOAS experiments that measure NO2 and NO3 near 450 and 630 nm, respectively. Average detection limits of 0.3 parts in 10(9) and 16 parts in 10(12) respectively, were obtained by use of a 6 km light path in the open atmosphere. PMID:16579579

  4. Measuring Active-Sterile Neutrino Oscillations with a Stopped Pion Neutrino Source

    NASA Astrophysics Data System (ADS)

    van de Water, Richard; Louis, Bill; Mills, Geoff

    2007-04-01

    The question of the existence of light sterile neutrinos is of great interest in many areas of particle physics, astrophysics, and cosmology. Furthermore, should the MiniBooNE experiment at Fermilab confirm the LSND oscillation signal, then new measurements are required to identify the mechanism responsible for these oscillations. Possibilities include sterile neutrinos, CP or CPT violation, variable mass neutrinos, and Lorentz violation. Here we consider an experiment at a stopped pion neutrino source (the Spallation Neutron Source at ORNL) to determine if active-sterile neutrino oscillations with δm ^2 greater than 0.1 eV^2 can account for the signal. By exploiting stopped +circ decay to produce a monoenergetic νμ source, and measuring the rate of the neutral current reaction νx0.05in ^12C ->νx0.05in ^12C^*(15.11) as a function of distance from the source, we show that a convincing test for active-sterile neutrino oscillations can be performed.

  5. Methodology of selecting the reference source for an active noise control system in a car.

    PubMed

    Dąbrowski, Zbigniew; Stankiewicz, Bartosz

    2013-01-01

    At the end of the 20th century, a significant development in digital technologies of signal processing made it possible to apply active noise control methods in new domains. A proper selection of the reference signal source is a main problem in implementing such systems. This paper presents an estimation method based on an indicator of the coherent power level. It also presents a simple system of active noise control in a car, operating according to the proposed method of optimising the positioning of reference sources. This system makes it possible to considerably increase the comfort of work of drivers in various kinds of road transport without a great increase in cost. This is especially significant in the case of trucks and vans. Passive barriers are considerably more expensive in them, which results in a higher level of noise than in passenger cars. PMID:23498706

  6. Quantification of Interictal Neuromagnetic Activity in Absence Epilepsy with Accumulated Source Imaging.

    PubMed

    Xiang, Jing; Tenney, Jeffrey R; Korman, Abraham M; Leiken, Kimberly; Rose, Douglas F; Harris, Elana; Yuan, Weihong; Horn, Paul S; Holland, Katherine; Loring, David W; Glauser, Tracy A

    2015-11-01

    Aberrant brain activity in childhood absence epilepsy (CAE) during seizures has been well recognized as synchronous 3 Hz spike-and-wave discharges on electroencephalography. However, brain activity from low- to very high-frequency ranges in subjects with CAE between seizures (interictal) has rarely been studied. Using a high-sampling rate magnetoencephalography (MEG) system, we studied ten subjects with clinically diagnosed but untreated CAE in comparison with age- and gender-matched controls. MEG data were recorded from all subjects during the resting state. MEG sources were assessed with accumulated source imaging, a new method optimized for localizing and quantifying spontaneous brain activity. MEG data were analyzed in nine frequency bands: delta (1-4 Hz), theta (4-8 Hz), alpha (8-12 Hz), beta (12-30 Hz), low-gamma (30-55 Hz), high-gamma (65-90 Hz), ripple (90-200 Hz), high-frequency oscillation (HFO, 200-1,000 Hz), and very high-frequency oscillation (VHFO, 1,000-2,000 Hz). MEG source imaging revealed that subjects with CAE had higher odds of interictal brain activity in 200-1,000 and 1,000-2,000 Hz in the parieto-occipito-temporal junction and the medial frontal cortices as compared with controls. The strength of the interictal brain activity in these regions was significantly elevated in the frequency bands of 90-200, 200-1,000 and 1,000-2,000 Hz for subjects with CAE as compared with controls. The results indicate that CAE has significantly aberrant brain activity between seizures that can be noninvasively detected. The measurements of high-frequency neuromagnetic oscillations may open a new window for investigating the cerebral mechanisms of interictal abnormalities in CAE. PMID:25359158

  7. The SPARX Project: R & D Activity Towards X-Rays FEL Sources

    SciTech Connect

    Alesini, D.; Bellaveglia, M.; Bertolucci, S.; Biagini, M.E.; Boni, R.; Boscolo, M.; Castellano, M.; Clozza, A.; Di Pirro, G.; Drago, A.; Esposito, A.; Ferrario, M.; Filippetto, D.; Fusco, V.; Gallo, A.; Ghigo, A.; Guiducci, S.; Incurvati, M.; Ligi, C.; Marcellini, F.; Migliorati, M.; /Frascati /ENEA, Frascati /INFN, Milan /INFN, Rome /INFN, Rome2 /Milan Polytechnic /UCLA /SLAC

    2005-08-05

    SPARX is an evolutionary project proposed by a collaboration among ENEA-INFN-CNR-Universita di Roma Tor Vergata aiming at the construction of a FELSASE X-ray source in the Tor Vergata Campus. The first phase of the SPARX project, funded by Government Agencies, will be focused on R&D activity on critical components and techniques for future X-ray facilities as described in this paper.

  8. Comparison of aerobic denitrifying activity among three cultural species with various carbon sources.

    PubMed

    Otani, Y; Hasegawa, K; Hanaki, K

    2004-01-01

    Abilities of three aerobic denitrifiers such as Alcaligenes faecalis, Microvirgula aerodenitrificans and Paracoccus pantotrophus were compared from the viewpoints of nitrate removal efficiency and organic matter utilization. First, the effect of carbon source was investigated. Although nitrate reduction was observed in all strains under aerobic conditions, a change of carbon source considerably affected the denitrification ability. In the case of P. pantotrophus, nitrate and nitrite were completely removed in three days under sodium acetate or leucine as a carbon source. In the case of A. faecalis, sufficient nitrate removal was observed only when sodium acetate or ethanol was added. P. pantotrophus and A. faecalis showed a higher ability of nitrate removal than that of M. aerodenitrificans. Therefore, P. pantotrophus was selected in order to investigate the effects of concentration and repetitive addition of carbon. Sodium acetate was used as a sole carbon source. Nitrate was not reduced when the carbon concentration was below 500 mgC/L. However, when carbon source was added repeatedly, nitrate was reduced under 100 mgC/L after the optical density of the bacterium reached above 1.0. This result indicated that a high enough level of bacterial density was necessary to express aerobic denitrification activity. PMID:15566182

  9. Development of the activation analysis calculational methodology for the Spallation Neutron Source (SNS)

    SciTech Connect

    Odano, N.; Johnson, J.O.; Charton, L.A.; Barnes, J.M.

    1998-03-01

    For the design of the proposed Spallation Neutron Source (SNS), activation analyses are required to determine the radioactive waste streams, on-line material processing requirements remote handling/maintenance requirements, potential site contamination and background radiation levels. For the conceptual design of the SNS, the activation analyses were carried out using the high-energy transport code HETC96 coupled with MCNP to generate the required nuclide production rates for the ORIHET95 isotope generation code. ORIHET95 utilizes a matrix-exponential method to study the buildup and decay of activities for any system for which the nuclide production rates are known. In this paper, details of the developed methodology adopted for the activation analyses in the conceptual design of the SNS are presented along with some typical results of the analyses.

  10. Evaluation of wild herbivore faeces from South Africa as a potential source of hydrolytically active microorganisms.

    PubMed

    Ndlela, Luyanda L; Schmidt, Stefan

    2016-01-01

    This study assessed faecal matter from three indigenous South African herbivores-zebra, giraffe and impala-as a potential source for hydrolytically active aerobic and facultatively anaerobic bacteria. Herbivore droppings were collected freshly in a local nature reserve in Pietermaritzburg, South Africa. Soil samples adjacent to faecal collection sites and faeces from a domestic herbivore, the Nguni cow, were included as controls. Hydrolase and dehydrogenase activity in faecal matter and soil samples were measured by the fluorescein diacetate and the triphenyltetrazolium chloride assay. Viable counts and counts for amylase, cellulase, esterase and protease producers were established using plate count agar and solid media containing cellulose, skim milk, starch and Tween 80. Zebra droppings produced the highest hydrolase and dehydrogenase activity. Faecal matter of the three indigenous herbivores generally produced higher hydrolytic activity than Nguni cow faeces and soil controls, thereby confirming that these materials are potential targets for hydrolytic enzyme mining. PMID:26900540

  11. Bayesian Inference for Neural Electromagnetic Source Localization: Analysis of MEG Visual Evoked Activity

    SciTech Connect

    George, J.S.; Schmidt, D.M.; Wood, C.C.

    1999-02-01

    We have developed a Bayesian approach to the analysis of neural electromagnetic (MEG/EEG) data that can incorporate or fuse information from other imaging modalities and addresses the ill-posed inverse problem by sarnpliig the many different solutions which could have produced the given data. From these samples one can draw probabilistic inferences about regions of activation. Our source model assumes a variable number of variable size cortical regions of stimulus-correlated activity. An active region consists of locations on the cortical surf ace, within a sphere centered on some location in cortex. The number and radi of active regions can vary to defined maximum values. The goal of the analysis is to determine the posterior probability distribution for the set of parameters that govern the number, location, and extent of active regions. Markov Chain Monte Carlo is used to generate a large sample of sets of parameters distributed according to the posterior distribution. This sample is representative of the many different source distributions that could account for given data, and allows identification of probable (i.e. consistent) features across solutions. Examples of the use of this analysis technique with both simulated and empirical MEG data are presented.

  12. Activity patterns of Californians: Use of and proximity to indoor pollutant sources

    NASA Astrophysics Data System (ADS)

    Jenkins, Peggy L.; Phillips, Thomas J.; Mulberg, Elliot J.; Hui, Steve P.

    The California Air Resources Board funded a statewide survey of activity patterns of Californians over 11 years of age in order to improve the accuracy of exposure assessments for air pollutants. Telephone interviews were conducted with 1762 respondents over the four seasons from fall 1987 through summer 1988. In addition to completing a 24-h recall diary of activities and locations, participants also responded to questions about their use of and proximity to potential pollutant sources. Results are presented regarding time spent by Californians in different activities and locations relevant to pollutant exposure, and their frequency of use of or proximity to pollutant sources including cigarettes, consumer products such as paints and deodorizers, combustion appliances and motor vehicles. The results show that Californians spend, on average, 87% of their time indoors, 7% in enclosed transit and 6% outdoors. At least 62% of the population over 11 years of age and 46% of nonsmokers are near others' tobacco smoke at some time during the day. Potential exposure to different pollutant sources appears to vary among different gender and age groups. For example, women are more likely to use or be near personal care products and household cleaning agents, while men are more likely to be exposed to environmental tobacco smoke, solvents and paints. Data from this study can be used to reduce significantly the uncertainty associated with risk assessments for many pollutants.

  13. Pattern reactivation co-varies with activity in the core recollection network during source memory.

    PubMed

    Leiker, Emily K; Johnson, Jeffrey D

    2015-08-01

    Neuroimaging studies of episodic memory have consistently demonstrated that memory retrieval involves reactivating patterns of neural activity that were present during encoding, and these effects are thought to reflect the qualitative retrieval (recollection) of information that is specific to the content of an episode. By contrast, recollection is also accompanied by other neural correlates that generalize across episodic content and are consequently referred to as the "core recollection network". The neural mechanism by which these specific and core effects interact to give rise to episodic memory retrieval is largely unknown. The current study addressed this issue by testing for correlations (connectivity) between pattern reactivation and activity in the core recollection network. Subjects encoded a series of words with different tasks and then completed a two-step source memory test, whereby they identified the task (source) previously associated with the word and the confidence of that judgment. Multivariate pattern analysis (MVPA) was used in combination with fMRI to first identify encoding-related neural patterns and then test for their reactivation during retrieval. Consistent with prior findings, the magnitude of reactivation increased with source-memory confidence. Moreover, individual-trial measures of reactivation exhibited positive correlations with activity in multiple regions of the core recollection network. Importantly, evidence of functional connectivity between pattern reactivation and a region of left posterior parietal cortex supports the role of this region in tracking the retrieval of episodic information in service of making subjective memory decisions. PMID:26004057

  14. Locating Local Earthquakes Using Single 3-Component Broadband Seismological Data

    NASA Astrophysics Data System (ADS)

    Das, S. B.; Mitra, S.

    2015-12-01

    We devised a technique to locate local earthquakes using single 3-component broadband seismograph and analyze the factors governing the accuracy of our result. The need for devising such a technique arises in regions of sparse seismic network. In state-of-the-art location algorithms, a minimum of three station recordings are required for obtaining well resolved locations. However, the problem arises when an event is recorded by less than three stations. This may be because of the following reasons: (a) down time of stations in a sparse network; (b) geographically isolated regions with limited logistic support to setup large network; (c) regions of insufficient economy for financing multi-station network and (d) poor signal-to-noise ratio for smaller events at most stations, except the one in its closest vicinity. Our technique provides a workable solution to the above problematic scenarios. However, our methodology is strongly dependent on the velocity model of the region. Our method uses a three step processing: (a) ascertain the back-azimuth of the event from the P-wave particle motion recorded on the horizontal components; (b) estimate the hypocentral distance using the S-P time; and (c) ascertain the emergent angle from the vertical and radial components. Once this is obtained, one can ray-trace through the 1-D velocity model to estimate the hypocentral location. We test our method on synthetic data, which produces results with 99% precision. With observed data, the accuracy of our results are very encouraging. The precision of our results depend on the signal-to-noise ratio (SNR) and choice of the right band-pass filter to isolate the P-wave signal. We used our method on minor aftershocks (3 < mb < 4) of the 2011 Sikkim earthquake using data from the Sikkim Himalayan network. Location of these events highlight the transverse strike-slip structure within the Indian plate, which was observed from source mechanism study of the mainshock and larger aftershocks.

  15. 26 CFR 1.863-8 - Source of income derived from space and ocean activity under section 863(d).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 9 2012-04-01 2012-04-01 false Source of income derived from space and ocean... to Taxable Years Prior to December 30, 1996 § 1.863-8 Source of income derived from space and ocean... space and ocean activity (space and ocean income) is sourced under the rules of this...

  16. 26 CFR 1.863-8 - Source of income derived from space and ocean activity under section 863(d).

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 9 2013-04-01 2013-04-01 false Source of income derived from space and ocean... to Taxable Years Prior to December 30, 1996 § 1.863-8 Source of income derived from space and ocean... space and ocean activity (space and ocean income) is sourced under the rules of this...

  17. 26 CFR 1.863-8 - Source of income derived from space and ocean activity under section 863(d).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 9 2014-04-01 2014-04-01 false Source of income derived from space and ocean... to Taxable Years Prior to December 30, 1996 § 1.863-8 Source of income derived from space and ocean... space and ocean activity (space and ocean income) is sourced under the rules of this...

  18. 26 CFR 1.863-9 - Source of income derived from communications activity under section 863(a), (d), and (e).

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 9 2012-04-01 2012-04-01 false Source of income derived from communications...) Regulations Applicable to Taxable Years Prior to December 30, 1996 § 1.863-9 Source of income derived from... ocean activity under section 863(d) and the regulations thereunder, the source of income derived...

  19. 26 CFR 1.863-9 - Source of income derived from communications activity under section 863(a), (d), and (e).

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 9 2014-04-01 2014-04-01 false Source of income derived from communications...) Regulations Applicable to Taxable Years Prior to December 30, 1996 § 1.863-9 Source of income derived from... ocean activity under section 863(d) and the regulations thereunder, the source of income derived...

  20. 26 CFR 1.863-9 - Source of income derived from communications activity under section 863(a), (d), and (e).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 26 Internal Revenue 9 2011-04-01 2011-04-01 false Source of income derived from communications...) Regulations Applicable to Taxable Years Prior to December 30, 1996 § 1.863-9 Source of income derived from... ocean activity under section 863(d) and the regulations thereunder, the source of income derived...

  1. Landslide dynamics from seismology and satellite remote sensing (Invited)

    NASA Astrophysics Data System (ADS)

    Stark, C. P.; Ekstrom, G.; Hibert, C.; Allen, J.

    2013-12-01

    Each year, a half-dozen or more kilometer-scale landslides strike mountain regions around the world. Each involves the acceleration and deceleration of millions of tons of debris at bulk rates of 1-3m/s^2, generating peak bulk-averaged forces well in excess of 10GN and exciting seismic waves whose long-period components are detectable at distances exceeding 1000km. We have studied around 40 such teleseismogenic (but not earthquake-triggered) landslides for the period 1980-2013, focusing mainly on inverting the long-period waveforms to infer time-series of landslide dynamical properties (the landslide force history or LFH; [1]), and recently extending our analysis to consider high-frequency seismicity recorded for well-instrumented events. It is now feasible to detect, measure and roughly geolocate >50GN, Msw>4.7 landslide events within a few hours of their occurrence, even if the landslides strike in very remote areas. Each rapid LFH inversion generates a good estimate of the runout geometry, which, for remote events, turns out to be very useful when trying to confirm and precisely locate the landslide occurrence in satellite imagery. With the advent of Landsat 8 it is now feasible to make such a confirmation within a week or so, weather permitting. A recent example is the rapid detection of a ~40Mt landslide in the Wrangell Mountains of Alaska that struck on 2013-07-25: the event was detected and roughly located with a few hours; within a few days, an LFH inversion gave its scale and runout path; the inversion and correlative short-period waveform analysis generated a sharper estimate for its location; a Landsat 8 image over the area was acquired within 8 days, and the new landslide scar was spotted shortly thereafter. This event extends our catalog of landslide source inversions and corroborates our general conclusions from this work, which are: (i) the glaciated mountains of Alaska, notably the St Elias Range and its neighbors, are the most catastrophic

  2. Assessing the previous activity at the source zone of the 2001 Bhuj earthquake based on the near-source and distant paleoseismological indicators

    NASA Astrophysics Data System (ADS)

    Rajendran, C. P.; Rajendran, Kusala; Thakkar, M.; Goyal, Bhanu

    2008-05-01

    The Mw 7.7 2001 Bhuj (Kachchh) earthquake was not associated with any primary surface rupture, but it produced secondary faulting, folding and liquefaction. This study highlights the potential of a secondary rupture and proxies like lateral spreads and sandblows in unraveling the past activity related to the 2001 source. Chronological constraints of an older lateral spread and far-field paleoliquefaction features, combined with archeological data, provide evidence for occurrences of two previous earthquakes at the 2001 source zone about 4000 and 9000 years, ago. Distinct stratigraphic evidence for at least one previous offset dated at 4424 ± 656 years could be detected at a stepover zone associated with a dextral secondary fault, reactivated during the 2001 earthquake. The studies imply longer interseismic intervals for the 2001 source zone, in comparison with the source zone of the 1819 earthquake located toward the northwestern part of the Rann of Kachchh. The spatial and temporal correlation of previous events derived on the basis of the available paleoseismic data from the region suggest not only repeated activity at the 2001 source, but possibility for additional potential sources in parts of Kachchh and Cambay basins. Although we infer a longer recurrence interval for the 2001 Bhuj earthquake source, our study points to the fact that these additional sources may have the potential to rupture in the future, considering the long elapsed time.

  3. Redox activity of urban quasi-ultrafine particles from primary and secondary sources

    NASA Astrophysics Data System (ADS)

    Verma, Vishal; Ning, Zhi; Cho, Arthur K.; Schauer, James J.; Shafer, Martin M.; Sioutas, Constantinos

    2009-12-01

    To characterize the redox activity profiles of atmospheric aerosols from primary (traffic) and secondary photochemical sources, ambient quasi-ultrafine particles were collected near downtown Los Angeles in two different time periods - morning (6:00-9:00 PDT) and afternoon (11:00-14:00 PDT) in the summer of 2008. Detailed chemical analysis of the collected samples, including water-soluble elements, inorganic ions, organic species and water soluble organic carbon (WSOC) was conducted and redox activity of the samples was measured by two different assays: the dithiothreitol (DTT) and the macrophage reactive oxygen species (ROS) assays. Tracers of secondary photochemical reactions, such as sulfate and organic acids were higher (2.1 ± 0.6 times for sulfate, and up to 3 times for the organic acids) in the afternoon period. WSOC was also elevated by 2.5 ± 0.9 times in the afternoon period due to photo-oxidation of primary particles during atmospheric aging. Redox activity measured by the DTT assay was considerably higher for the samples collected during the afternoon; on the other hand, diurnal trends in the ROS-based activity were not consistent between the morning and afternoon periods. A linear regression between redox activity and various PM chemical constituents showed that the DTT assay was highly correlated with WSOC ( R2 = 0.80), while ROS activity was associated mostly with water soluble transition metals (Vanadium, Nickel and Cadmium; R2 > 0.70). The DTT and ROS assays, which are based on the generation of different oxidizing species by chemical PM constituents, provide important information for elucidating the health risks related to PM exposure from different sources. Thus, both primary and secondary particles possess high redox activity; however, photochemical transformations of primary emissions with atmospheric aging enhance the toxicological potency of primary particles in terms of generating oxidative stress and leading to subsequent damage in cells.

  4. 40 CFR Table 3 to Part 455 - Organic Pesticide Active Ingredient New Source Performance Standards (NSPS) and Pretreatment...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Organic Pesticide Active Ingredient... STANDARDS PESTICIDE CHEMICALS Pt. 455, Table 3 Table 3 to Part 455—Organic Pesticide Active Ingredient New Source Performance Standards (NSPS) and Pretreatment Standards for New Sources (PSNS) Pesticide...

  5. 40 CFR Table 3 to Part 455 - Organic Pesticide Active Ingredient New Source Performance Standards (NSPS) and Pretreatment...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Organic Pesticide Active Ingredient... STANDARDS PESTICIDE CHEMICALS Pt. 455, Table 3 Table 3 to Part 455—Organic Pesticide Active Ingredient New Source Performance Standards (NSPS) and Pretreatment Standards for New Sources (PSNS) Pesticide...

  6. Sources and evolution of cloud-active aerosol in California's Sierra Nevada Mountains

    NASA Astrophysics Data System (ADS)

    Roberts, G. C.; Corrigan, C.; Noblitt, S.; Creamean, J.; Collins, D. B.; Cahill, J. F.; Prather, K. A.; Collett, J. L.; Henry, C.

    2011-12-01

    To assess the sources of cloud-active aerosol and their influence on the hydrological cycle in California, the CalWater Experiment took place in winter 2011 in the foothills of the Sierra Nevada Mountains. During this experiment, we coupled the capabilities of demonstrated miniaturized instrumentation - cloud condensation nuclei (CCN), water condensation nuclei (WCN) and microchip capillary electrophoresis (MCE) - to provide direct chemical measurements of cloud active aerosols. Ion concentrations of CCN droplets attribute the anthropogenic, marine and secondary organic contributions to cloud-active aerosols. Detailed spectra from an Aerosol-Time-of-Flight Mass Spectrometer provide additional information on the sources of aerosol. Storm fronts and changes in atmospheric boundary layer brought aerosol and anions associated with Central Valley pollution to the field site with CCN concentrations reaching several thousand cm-3. Hygroscopicity parameters indicate aging of the organic fraction during aerosol transport from the Central Valley to the mountains. Otherwise, CCN concentrations were low when high pressure systems prevented boundary layer development and intrusion of the Central Valley pollution to the site. MCE results show that nitrates and sulfates comprise most of the fraction of the aerosol anion mass (PM1). During the passage of storm fronts, which transported pollution from the Central Valley upslope, nitrate concentrations peaked at several μ g m-3. Low supersaturation CCN concentrations coincide with increases in aerosol nitrate, which suggests that nitrate has a role in cloud formation of giant CCN and, furthermore, in precipitation processes in the Sierra Nevada. CCN spectra show large variations depending on the aerosol sources and sometimes exhibit bi-modal distributions with minima at 0.3% Sc -- similar to the so-called 'Hoppel minima' associated to number size distributions. During these bi-modal events, sulfate also increases supporting the

  7. Design considerations for neutron activation and neutron source strength monitors for ITER

    SciTech Connect

    Barnes, C.W.; Jassby, D.L.; LeMunyan, G.; Roquemore, A.L.; Walker, C.

    1997-12-31

    The International Thermonuclear Experimental Reactor will require highly accurate measurements of fusion power production in time, space, and energy. Spectrometers in the neutron camera could do it all, but experience has taught us that multiple methods with redundancy and complementary uncertainties are needed. Previously, conceptual designs have been presented for time-integrated neutron activation and time-dependent neutron source strength monitors, both of which will be important parts of the integrated suite of neutron diagnostics for this purpose. The primary goals of the neutron activation system are: to maintain a robust relative measure of fusion energy production with stability and wide dynamic range; to enable an accurate absolute calibration of fusion power using neutronic techniques as successfully demonstrated on JET and TFTR; and to provide a flexible system for materials testing. The greatest difficulty is that the irradiation locations need to be close to plasma with a wide field of view. The routing of the pneumatic system is difficult because of minimum radius of curvature requirements and because of the careful need for containment of the tritium and activated air. The neutron source strength system needs to provide real-time source strength vs. time with {approximately}1 ms resolution and wide dynamic range in a robust and reliable manner with the capability to be absolutely calibrated by in-situ neutron sources as done on TFTR, JT-60U, and JET. In this paper a more detailed look at the expected neutron flux field around ITER is folded into a more complete design of the fission chamber system.

  8. Pattern recognition in volcano seismology - Reducing spectral dimensionality

    NASA Astrophysics Data System (ADS)

    Unglert, K.; Radic, V.; Jellinek, M.

    2015-12-01

    Variations in the spectral content of volcano seismicity can relate to changes in volcanic activity. Low-frequency seismic signals often precede or accompany volcanic eruptions. However, they are commonly manually identified in spectra or spectrograms, and their definition in spectral space differs from one volcanic setting to the next. Increasingly long time series of monitoring data at volcano observatories require automated tools to facilitate rapid processing and aid with pattern identification related to impending eruptions. Furthermore, knowledge transfer between volcanic settings is difficult if the methods to identify and analyze the characteristics of seismic signals differ. To address these challenges we evaluate whether a machine learning technique called Self-Organizing Maps (SOMs) can be used to characterize the dominant spectral components of volcano seismicity without the need for any a priori knowledge of different signal classes. This could reduce the dimensions of the spectral space typically analyzed by orders of magnitude, and enable rapid processing and visualization. Preliminary results suggest that the temporal evolution of volcano seismicity at Kilauea Volcano, Hawai`i, can be reduced to as few as 2 spectral components by using a combination of SOMs and cluster analysis. We will further refine our methodology with several datasets from Hawai`i and Alaska, among others, and compare it to other techniques.

  9. Activity Variation of Phanerochaete chrysosporium under Nanosilver Exposure by Controlling of Different Sulfide Sources.

    PubMed

    Guo, Zhi; Chen, Guiqiu; Liu, Lingzhi; Zeng, Guangming; Huang, Zhenzhen; Chen, Anwei; Hu, Liang

    2016-01-01

    Due to the particular activation and inhibition behavior of silver nanoparticles (AgNPs) on microbes at various concentrations, it's crucial to exploit the special concentration effect in environment. Here, we studied the viability variation of Phanerochaete chrysosporium (P. chrysosporium) under exposure to citrate-coated AgNPs (Citrate-AgNPs) in the presence of different sulfide sources (an inorganic sulfide, NaHS and an organic sulfide, thioacetamide (TAA)). The results indicated that both NaHS and TAA can promote activation of P. chrysosporium by Citrate-AgNPs at a higher concentration, which was initial at toxic level. Treatment with various concentrations of Citrate-AgNPs (0-9 mg/L) demonstrated a maximum activation concentration (MAC) at 3 mg/L. With the increase in sulfide concentration, MAC transferred to higher concentration significantly, indicating the obvious "toxicity to activation" transformation at a higher concentration. Ag(+) testing exhibited that variations in sulfide-induced Ag(+) concentration (3-7 μg/L Ag(+)) accounted for the "toxicity to activation" transformation. In addition, the similar results were observed on antibacterial application using Escherichia coli as the model species. Based on the research results, the application of this transformation in improving antibacterial activity was proposed. Therefore, the antibacterial activity of AgNPs can be controlled, even at concentration, via adjusting for the sulfide concentration. PMID:26864597

  10. Infrasound research at Kola Regional Seismological Centre, Russia

    NASA Astrophysics Data System (ADS)

    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

  11. Look who's judging-Feedback source modulates brain activation to performance feedback in social anxiety.

    PubMed

    Peterburs, Jutta; Sandrock, Carolin; Miltner, Wolfgang H R; Straube, Thomas

    2016-06-01

    It is as yet unknown if behavioral and neural correlates of performance monitoring in socially anxious individuals are affected by whether feedback is provided by a person or a computer. This fMRI study investigated modulation of feedback processing by feedback source (person vs. computer) in participants with high (HSA) (N=16) and low social anxiety (LSA) (N=16). Subjects performed a choice task in which they were informed that they would receive positive or negative feedback from a person or the computer. Subjective ratings indicated increased arousal and anxiety in HSA versus LSA, most pronounced for social and negative feedback. FMRI analyses yielded hyperactivation in ventral medial prefrontal cortex (vmPFC)/anterior cingulate cortex (ACC) and insula for social relative to computer feedback, and in mPFC/ventral ACC for positive relative to negative feedback in HSA as compared to LSA. These activation patterns are consistent with increased interoception and self-referential processing in social anxiety, especially during processing of positive feedback. Increased ACC activation in HSA to positive feedback may link to unexpectedness of (social) praise as posited in social anxiety disorder (SAD) psychopathology. Activation in rostral ACC showed a reversed pattern, with decreased activation to positive feedback in HSA, possibly indicating altered action values depending on feedback source and valence. The present findings corroborate a crucial role of mPFC for performance monitoring in social anxiety. PMID:27033687

  12. Astaxanthin: Sources, Extraction, Stability, Biological Activities and Its Commercial Applications—A Review

    PubMed Central

    Ambati, Ranga Rao; Siew Moi, Phang; Ravi, Sarada; Aswathanarayana, Ravishankar Gokare

    2014-01-01

    There is currently much interest in biological active compounds derived from natural resources, especially compounds that can efficiently act on molecular targets, which are involved in various diseases. Astaxanthin (3,3′-dihydroxy-β, β′-carotene-4,4′-dione) is a xanthophyll carotenoid, contained in Haematococcus pluvialis, Chlorella zofingiensis, Chlorococcum, and Phaffia rhodozyma. It accumulates up to 3.8% on the dry weight basis in H. pluvialis. Our recent published data on astaxanthin extraction, analysis, stability studies, and its biological activities results were added to this review paper. Based on our results and current literature, astaxanthin showed potential biological activity in in vitro and in vivo models. These studies emphasize the influence of astaxanthin and its beneficial effects on the metabolism in animals and humans. Bioavailability of astaxanthin in animals was enhanced after feeding Haematococcus biomass as a source of astaxanthin. Astaxanthin, used as a nutritional supplement, antioxidant and anticancer agent, prevents diabetes, cardiovascular diseases, and neurodegenerative disorders, and also stimulates immunization. Astaxanthin products are used for commercial applications in the dosage forms as tablets, capsules, syrups, oils, soft gels, creams, biomass and granulated powders. Astaxanthin patent applications are available in food, feed and nutraceutical applications. The current review provides up-to-date information on astaxanthin sources, extraction, analysis, stability, biological activities, health benefits and special attention paid to its commercial applications. PMID:24402174

  13. Astaxanthin: sources, extraction, stability, biological activities and its commercial applications--a review.

    PubMed

    Ambati, Ranga Rao; Phang, Siew Moi; Ravi, Sarada; Aswathanarayana, Ravishankar Gokare

    2014-01-01

    There is currently much interest in biological active compounds derived from natural resources, especially compounds that can efficiently act on molecular targets, which are involved in various diseases. Astaxanthin (3,3'-dihydroxy-β, β'-carotene-4,4'-dione) is a xanthophyll carotenoid, contained in Haematococcus pluvialis, Chlorella zofingiensis, Chlorococcum, and Phaffia rhodozyma. It accumulates up to 3.8% on the dry weight basis in H. pluvialis. Our recent published data on astaxanthin extraction, analysis, stability studies, and its biological activities results were added to this review paper. Based on our results and current literature, astaxanthin showed potential biological activity in in vitro and in vivo models. These studies emphasize the influence of astaxanthin and its beneficial effects on the metabolism in animals and humans. Bioavailability of astaxanthin in animals was enhanced after feeding Haematococcus biomass as a source of astaxanthin. Astaxanthin, used as a nutritional supplement, antioxidant and anticancer agent, prevents diabetes, cardiovascular diseases, and neurodegenerative disorders, and also stimulates immunization. Astaxanthin products are used for commercial applications in the dosage forms as tablets, capsules, syrups, oils, soft gels, creams, biomass and granulated powders. Astaxanthin patent applications are available in food, feed and nutraceutical applications. The current review provides up-to-date information on astaxanthin sources, extraction, analysis, stability, biological activities, health benefits and special attention paid to its commercial applications. PMID:24402174

  14. Infrasound Interferometry for Active and Passive Sources: A Synthetic Example for Waves Refracted in the Stratosphere

    NASA Astrophysics Data System (ADS)

    Fricke, J.; Ruigrok, E. N.; Evers, L. G.; El Allouche, N.; Simons, D.; Wapenaar, C. A.

    2012-12-01

    The travel time of infrasound through the stratosphere depends on the temperature profile and the wind speed. These atmospheric conditions can be estimated by determining the travel times between different receivers (microbarometers). Therefore the determination of the travel time of infrasound between different receivers becomes more and more important. An approach to determine the travel time is infrasound interferometry. In this work, the infrasound interferometry is applied to synthetic data of active and passive sources refracted by the stratosphere is tested. The synthetic data were generated with a raytracing model. The inputs of the raytracing model are the atmospheric conditions and a source wavelet. As source wavelet we used blast waves and microbaroms. With the atmospheric conditions and the source wavelet the raytracing model calculates the raypath and the travel time of the infrasound. In order to simulate the measurement of a receiver the rays which reach the receiver need to be found. The rays which propagate from a source to the receiver are called eigen rays. The simulation of the receiver measurements takes into account the travel time along the eigen rays, the attenuation of the different atmospheric layers, the spreading of the rays and the influence of caustics. The simulated measurements of the different receivers are combined to synthetic barograms. Two synthetic experiments were performed with the described model. In the first experiment the interferometry was applied to barograms of active sources like blast waves. The second experiment with microbaroms tests the applicability of interferometry to barograms of passive sources. In the next step infrasound interferometry will be applied to measured barograms. These barograms are measured with the 'Large Aperture Infrasound Array' (LAIA). LAIA is being installed by the Royal Netherlands Meteorological Institute (KNMI) in the framework of the radio-astronomical 'Low Frequency Array' (LOFAR

  15. Coordinated activation of distinct Ca(2+) sources and metabotropic glutamate receptors encodes Hebbian synaptic plasticity.

    PubMed

    Tigaret, Cezar M; Olivo, Valeria; Sadowski, Josef H L P; Ashby, Michael C; Mellor, Jack R

    2016-01-01

    At glutamatergic synapses, induction of associative synaptic plasticity requires time-correlated presynaptic and postsynaptic spikes to activate postsynaptic NMDA receptors (NMDARs). The magnitudes of the ensuing Ca2+ transients within dendritic spines are thought to determine the amplitude and direction of synaptic change. In contrast, we show that at mature hippocampal Schaffer collateral synapses the magnitudes of Ca2+ transients during plasticity induction do not match this rule. Indeed, LTP induced by time-correlated pre- and postsynaptic spikes instead requires the sequential activation of NMDARs followed by voltage-sensitive Ca2+ channels within dendritic spines. Furthermore, LTP requires inhibition of SK channels by mGluR1, which removes a negative feedback loop that constitutively regulates NMDARs. Therefore, rather than being controlled simply by the magnitude of the postsynaptic calcium rise, LTP induction requires the coordinated activation of distinct sources of Ca2+ and mGluR1-dependent facilitation of NMDAR function. PMID:26758963

  16. Coordinated activation of distinct Ca2+ sources and metabotropic glutamate receptors encodes Hebbian synaptic plasticity

    PubMed Central

    Tigaret, Cezar M.; Olivo, Valeria; Sadowski, Josef H.L.P.; Ashby, Michael C.; Mellor, Jack R.

    2016-01-01

    At glutamatergic synapses, induction of associative synaptic plasticity requires time-correlated presynaptic and postsynaptic spikes to activate postsynaptic NMDA receptors (NMDARs). The magnitudes of the ensuing Ca2+ transients within dendritic spines are thought to determine the amplitude and direction of synaptic change. In contrast, we show that at mature hippocampal Schaffer collateral synapses the magnitudes of Ca2+ transients during plasticity induction do not match this rule. Indeed, LTP induced by time-correlated pre- and postsynaptic spikes instead requires the sequential activation of NMDARs followed by voltage-sensitive Ca2+ channels within dendritic spines. Furthermore, LTP requires inhibition of SK channels by mGluR1, which removes a negative feedback loop that constitutively regulates NMDARs. Therefore, rather than being controlled simply by the magnitude of the postsynaptic calcium rise, LTP induction requires the coordinated activation of distinct sources of Ca2+ and mGluR1-dependent facilitation of NMDAR function. PMID:26758963

  17. Source localization for active control of turbofan rotor-stator broadband noise

    NASA Astrophysics Data System (ADS)

    Walker, Bruce E.

    2005-09-01

    In order to identify a reference signal source for an active noise cancellation system, cross-correlation techniques were used to localize broadband noise source regions on exit guide vanes of the NASA Glenn Research Center Advance Noise Control Fan (ANCF). Arrays of surface pressure sensors were imbedded in one guide vane and in the wall of the fan. Synchronous sampling was used with a multichannel data acquisition system to allow removal of periodic components from the signals. The signals were then cross-correlated to assess radiation directivity and the relationship between vane surface pressure and in-duct acoustic noise. The results of these measurements indicated that broadband unsteady pressures near the leading edge tip of the guide vane were well enough correlated with acoustic radiation that 2-3 dB active noise cancellation could be achieved using a simple gain-delay control algorithm and actuator array. After successful simulation in a wind tunnel environment the concept was incorporated on 15 guide vanes and tested in ANCF. Cross-correlation measurements were further used to evaluate system performance and to identify competing noises from rotating and stationary sources within the fan.

  18. Interplanetary scintillations of the radio source ensemble at the maximum of cycle 24 of solar activity

    NASA Astrophysics Data System (ADS)

    Chashei, I. V.; Shishov, V. I.; Tyul'bashev, S. A.; Subaev, I. A.

    2016-05-01

    The results of the interplanetary scintillation observations performed in the period of the maximum of solar activity from April 2013 to April 2014 on the BSA LPI radio telescope at the frequency 111MHz are presented. Fluctuations of the radio emission flux were recorded round the clock for all sources with a scintillating flux of more than 0.2 Jy falling in a strip of sky with a width of 50° over declinations corresponding to a 96-beam directional pattern of the radio telescope. The total number of sources observed during the day reaches 5000. The processing of the observational data was carried out on the assumption that a set of scintillating sources represents a homogeneous statistical ensemble. Daily two-dimensional maps of the distribution of the level of scintillations, whose analysis shows the strong nonstationarity and large-scale irregularity of the spatial distribution of solar wind parameters, were constructed. According to maps of the distribution of the level of scintillations averaged over monthly intervals, the global structure of the distribution of the solar wind was investigated in the period of the maximum of solar activity, which was found to be on the average close to spherically symmetric. The data show that on a spherically symmetric background an east-west asymmetry is observed, which indicates the presence of a large-scale structure of a spiral type in the solar wind.

  19. Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

    NASA Technical Reports Server (NTRS)

    Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

    1994-01-01

    An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

  20. Active control of aircraft engine inlet noise using compact sound sources and distributed error sensors

    NASA Technical Reports Server (NTRS)

    Burdisso, Ricardo (Inventor); Fuller, Chris R. (Inventor); O'Brien, Walter F. (Inventor); Thomas, Russell H. (Inventor); Dungan, Mary E. (Inventor)

    1996-01-01

    An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet. These panels are flush mounted inside the inlet duct and sealed on all edges to prevent leakage around the panel and to minimize the aerodynamic losses created by the addition of the panels. Each panel is driven by one or more piezoelectric force transducers mounted on the surface of the panel. The response of the panel to excitation is maximized when it is driven at its resonance; therefore, the panel is designed such that its fundamental frequency is near the tone to be canceled, typically 2000-4000 Hz.

  1. Computation of instantaneous and time-averaged active acoustic intensity field around rotating source

    NASA Astrophysics Data System (ADS)

    Mao, Yijun; Xu, Chen; Qi, Datong

    2015-02-01

    A vector aeroacoustics method is developed to analyze the acoustic energy flow path from the rotating source. In this method, the instantaneous and time-averaged active acoustic intensity vectors are evaluated from the time-domain and frequency-domain acoustic pressure and acoustic velocity formulations, respectively. With the above method, the acoustic intensity vectors and the acoustic energy streamlines are visualized to investigate the propagation feature of the noise radiated from the monopole and dipole point sources and the rotor in subsonic rotation. The result reveals that a portion of the acoustic energy spirals many circles before moving towards the far field, and another portion of the acoustic energy firstly flows inward along the radial direction and then propagates along the axial direction. Further, an acoustic black hole exists in the plane of source rotation, from which the acoustic energy cannot escape once the acoustic energy flows into it. Moreover, by visualizing the acoustic intensity field around the rotating sources, the acoustic-absorption performance of the acoustic liner built in the casing and centerbody is discussed.

  2. Impact of floral sources and processing on the antimicrobial activities of different unifloral honeys

    PubMed Central

    Elbanna, Khaled; Attalla, Khaled; Elbadry, Medhat; Abdeltawab, Awad; Gamal-Eldin, Hosny; Ramadan, Mohamed Fawzy

    2014-01-01

    Objective To study in vitro antibacterial activity and physicochemical properties of three unifloral honeys (citrus, clover and cotton honeys), and to study the impacts of storage, dilution with water (33%, w/v) and autoclaving (121 °C for 15 min) on honeys characteristics. Methods Honey samples from monofloral sources including citrus (Citrus spp.), Egyptian clover (Trifolium alexandrium) and cotton (Gossypium vitifolium) were obtained during three successive seasons (2010-2012). Physicochemical properties and antimicrobial activities of different honey samples were studies. Results In honey samples stored for 12 or 24 month, colour, hydroxymethyl furfural and acidity increased, while refractive index, water activity, total soluble solids, electrical conductivity and pH remained relatively unaffected, but H2O2 values decreased. Types of honey exhibited various degrees of antibacterial activity against different indicator bacteria, wherein the highest antibacterial activity was recorded for clover honey followed by citrus and cotton honeys, respectively. Different species of bacteria were differed in their sensitivity to honey, wherein Salmonella enteritidis was the most sensitive followed by Staphylococcus aureus, Listeria monocytogenes and Escherichia coli, respectively. Storage up to 24 months at room temperature slightly reduced the antibacterial activity. The reduction levels were about 2.6% and 4.6% after 12 and 24 months, respectively