| Earthquakes: Risk, Detection, Warning, and Research |
14 Jan 2010 |
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| Authors:
Peter Folger; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
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 | The 1994 Northridge (CA) earthquake caused as much as $26 billion (in 2005 dollars) in damage and was one of the costliest natural disasters to strike the United States. The Federal Emergency Management Agency has estimated that earthquakes cost the United States over $5 billion per year. A hypothetical scenario for a magnitude 7.8 earthquake in southern California estimated a possibility of 1,800 fatalities and over $200 billion in economic ... |
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| Pathfinder, Volume 7, Number 6, November/December 2009 |
Dec 2009 |
29 pages |
| Authors:
NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY (NGA) BETHESDA MD
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 | GEOINT Saves Lives -- Global Humanitarian Support and Disaster Relief: Washingtonian magazine, in its November 2009 issue, showcased NGA as one of the 50 great places to work in the Washington, D.C. area and one of five federal agencies featured. We were recognized for, among other things, our challenging work and mission and how much of a difference we are making. One example of our mission responsibilities is our support ... |
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| Source and Path Calibration in Regions of Poor Crustal Propagation using Temporary, Large-Aperture, High-Resolution Seismic Arrays |
30-Sep-2009 |
9 pages |
| Authors:
John L Nabelek; Jochen Braunmiller; W S Phillips; OREGON STATE UNIV CORVALLIS
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| Broadband seismic data acquired during the Hi-CLIMB field experiment are used to study seismic events and path propagation in the Nepal Himalaya and south-central Tibetan Plateau. Similarities in regional propagation between Tibet and Iran motivate this new study. The 2002-2005 Hi-CLIMB experiment consisted of 233 stations distributed along a dense 800 km linear north-south array extending from the Himalayan foreland into the central Tibetan Plateau. The main array was flanked ... |
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| 3D Modeling of Iran and Surrounding Areas from Simultaneous Inversion of Multiple Geophysical Datasets |
30-Sep-2009 |
10 pages |
| Authors:
Charles J Ammon; Monica Maceira; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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| The objective of this work is to help improve seismic monitoring technology through the development and application of advanced multivariate inversion techniques to generate realistic, comprehensive, and high-resolution 3D models of the seismic structure of the crust and upper mantle that satisfy independent geophysical datasets. Our focus is on the region surrounding Iran from the east coast of the Mediterranean in the west, to Pakistan in the east, an area ... |
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| Crustal Structure from In-Country and Ground-Truth Data |
30-Sep-2009 |
11 pages |
| Authors:
Eric A Bergman; Michael H Ritzwoller; Stephen C Myers; E R Engdahl; COLORADO UNIV AT BOULDER
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| We are investigating the crustal and upper mantle structure of the region in central Asia bounded approximately by longitude 41-67 deg E and latitude 20-44 deg N by using in-country datasets of seismic phase arrival times, supplemented by ground truth datasets developed from our previous research efforts. We present the results of Pn tomography using a dataset consisting entirely of GT5 events in the region. From 27 calibrated earthquake clusters ... |
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| Seismo-Acoustic Generation by Earthquakes and Explosions and Near-Regional Propagation |
30-Sep-2009 |
10 pages |
| Authors:
Relu Burlacu; Kristine Pankow; Tae-Sung Kim; Stephen J Arrowsmith; Brian W Stump; Christopher T Hayward; Rongmao Zhou; SOUTHERN METHODIST UNIV DALLAS TX
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| Seismo-acoustic measurements provide an opportunity to quantify natural and man-made sources that are at or near the Earth's surface. We have operated three acoustic arrays collocated with seismometers from the University of Utah Seismograph Stations (BGU, EPU, NOQ). We report on progress in three separate areas of research related to these seismo-acoustic databases. The first topic investigates seismo-acoustic signals from the Wells, Nevada earthquake that occurred on February 21, 2008 ... |
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| Improved Phase Characterization of Far-Regional Body Wave Arrivals in Central Asia |
30-Sep-2009 |
11 pages |
| Authors:
Delaine Reiter; Katherine Murphy; Aaron Ferris; WESTON GEOPHYSICAL CORP LEXINGTON MA
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| The early body-wave coda of far-regional events (14 - 29 degrees) contains triplicated arrivals from upper-mantle discontinuities that, when properly identified, can improve seismic monitoring functions. However, far-regional seismograms are typically under-utilized because along-path heterogeneity and phase interactions make the arrival suite difficult to interpret accurately. We have developed a set of techniques for small aperture arrays that improve phase characterization and identification at these distances. We have focused our ... |
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| Estimating the Uncertainty and Predictive Capabilities of Three-Dimensional Earth Models |
30-Sep-2009 |
11 pages |
| Authors:
Stephen C Myers; Delaine T Reiter; William L Rodi; WESTON GEOPHYSICAL LEXINGTON MA
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| Many three-dimensional models of seismic velocity structure in Eurasia have been developed in recent years by the seismic nuclear monitoring community. Most of these models are not accompanied by quantitative estimates of uncertainty, either in the model velocities themselves or in geophysical observables predicted by the models (e.g., body-wave travel times). Moreover, the various 3D models produced by these studies have not been compared to one another for their predictive ... |
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| A Stepwise, Iterative Procedure to Constrain Stress Drop, Regional Attenuation Models, and Site Effects |
30-Sep-2009 |
11 pages |
| Authors:
W S Phillips; Mark D Fisk; ALLIANT TECHSYSTEMS INC SAN DIEGO CA
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| Accurate corrections for distance, source size, and site effects are needed for reliable use of regional seismic phases for discrimination and magnitude estimation. Procedures that simultaneously invert for attenuation, geometrical spreading, site, and source parameters have been shown to include many trade-offs and instabilities that have led to significantly inaccurate corrections for distance and source terms. Under previous work, we developed and applied an approach to constrain source parameters, including ... |
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| Analysis and Simulation of 3D Scattering due to Heterogeneous Crustal Structure and Surface Topography on Regional Phases; Magnitude and Discrimination |
07-Jul-2009 |
61 pages |
| Authors:
Arben Pitarka; Donald V Helmberger; URS GROUP INC PASADENA CA
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| This report concentrates on generating physical explanation for commonly used discriminants. It begins with a brief review of broadband observations from earthquakes and an explosion occurring in North Korea. By comparing detailed earthquake modeling results, we confirm the existence of radiation pattern for body wave arrival onsets to high-frequency, 8 Hz. We also addressed the coda-levels for all three components and demonstrate that the (P/S) spectral levels provide a useful ... |
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| Simulating Tsunamis in the Indian Ocean with Real Bathymetry by using a High- Order Triangular Discontinuous Galerkin Oceanic Shallow Water Model |
Mar-2009 |
113 pages |
| Authors:
Dimitrios Alevras; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The discontinuous Galerkin (DG) method has been accepted in the last decade by the geosciences community as an important component of geophysical fluid dynamics. The high-order accuracy, geometric flexibility to use unstructured grids, local conservation, and monotonicity properties of the DG method make it a prime candidate for the construction of future ocean and shallow water models. This study focuses on formatting real bathymetry data of the Indian Ocean in ... |
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| Imaging a Hydrate-Related Cold Vent Offshore Vancouver Island From Deep-Towed Multichannel Seismic Data |
20 Feb 2009 |
15 pages |
| Authors:
Tao He; George D Spence; Warren T Wood; Michael Riedel; Roy D Hyndman; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS MARINE GEOACOUSTICS DIV
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| The Bullseye vent, an approximately 500-m-diameter deep sea, hydrate-related cold vent on the midslope offshore Vancouver Island, was imaged in a high-resolution multichannel survey by the Deep-towed Acoustics and Geophysics System (DTAGS) The structure was drilled by the Integrated Ocean Drilling Program at site U1328. Towed about 300 m above the seafloor, the high-frequency (220-820 Hz) DTAGS system provides a high vertical and lateral resolution image. The major problems in ... |
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| Developments of Finite-Frequency Seismic Theory and Applications to Regional Tomographic Imaging |
31-Jan-2009 |
54 pages |
| Authors:
Xiaoping Yang; Yang Shen; SCIENCE APPLICATIONS INTERNATIONAL CORP (SAIC) ARLINGTON VA
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| We use banana-doughnut sensitivity kernels of teleseismic body waves to image the crust and mantle beneath eastern Eurasia. We have collected and processed available broadband data from both permanent stations and temporary networks in eastern Eurasia. In southeast Tibet, where a PASSCAL experiment provided a dense station coverage, a detailed study is carried out to obtain high-resolution P- and Svelocity models. A regional P-wave velocity model for eastern Eurasia is ... |
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| Static Experiments of Partially Buried Cased Charges Against Earth and Timber Bunkers |
Jan-2009 |
18 pages |
| Authors:
Richard Pearson; Amy Tank; Denis Rickman; Jay Ehrgott; Jason Angel; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| The US Army Research Laboratory (ARL), in conjunction with the Engineer Research and Development Center (ERDC), performed experiments to assess the effects of a partially buried charge against an earth and timber bunker. The experiments were designed to evaluate the ground shock and airblast environment, as well as the resultant loads on the bunker, produced by a cased charge with a TNT-equivalence of 41.4 Kg. ARL's Model of Earth and ... |
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| Pakistan Earthquake Case Study |
Jan-2009 |
23 pages |
| Authors:
Phister; Paul W Jr; Dave Allen; Julius Barath; Ulrich Brandenberger; Ralph Bruehlmann; Alain Burton; Philip W Farrell; Geert Marien; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH
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| As part of SAS-065, a number of case studies were examined to determine the validity of the NATO NEC C2 Maturity Model (N2C2M2). A group decided to example the earthquake that occurred in Pakistan on 8 Oct 05 to determine if there was a good application of the N2C2M2 to a natural disaster. An earthquake measuring 7.6 on the Richter scale hit northern Pakistan on 8 Oct 05. As shown ... |
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| Seismic Characterization Study of the Advanced Inertial Test Laboratory (AITL) Report |
08-Dec-2008 |
95 pages |
| Authors:
Cleon Baker; William Rock; TEST SQUADRON ( 746TH) HOLLOMAN AFB NM
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| The Advanced Inertial Test Laboratory (AITL) is the most seismically quiet test facility in the nation. However, due to poor isolation of newly installed environmental support equipment (ESE) and improper upkeeping of existing isolation, the seismic test environment has been compromised. In order to quantify the current seismic environment, this study was conducted from 24 July 07 to 26 March 08. This report presents the results of the study, along ... |
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| Frequency-Dependent Nature of Pn in Western China: Gaussian Beam Modeling of Data from the Hi-CLIMB Experiment |
30-Sep-2008 |
11 pages |
| Authors:
Robert L Nowack; Wang-Ping Chen; Tai-Lin Tseng; PURDUE UNIV LAFAYETTE IN
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| In realistic models of the crust and the upper mantle where vertical gradients in wave speeds and major interfaces are present, propagation of Pn, an important seismic phase at regional distances, involves complex effects of interference. Such effects can result in wave-trains whose frequency-contents and amplitudes vary with distance in counter-intuitive ways. In this new project, we are investigating the propagation of Pn beneath western China using data from Hi-CLIMB ... |
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| Crustal Structure of the Iran Region from In-Country and Ground-Truth Data |
30-Sep-2008 |
8 pages |
| Authors:
Eric A Bergman; Eric R Engdahl; Michael H Ritzwoller; Stephen C Myers; COLORADO UNIV AT BOULDER
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| We are investigating the crustal and upper mantle structure of the Iran region using in-country data sets of seismic phase arrival times, supplemented by ground-truth data sets developed from our previous research efforts. Other data sets from global, regional, and national bulletins in the region are being integrated as well. The in-country data sets, covering approximately the last 10 years of seismicity in the region, are being carefully reviewed for ... |
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| Wave Propagation from Complex 3D Sources Using the Representation Theorem |
30-Sep-2008 |
11 pages |
| Authors:
Heming Xu; Jeffry L Stevens; SCIENCE APPLICATIONS INTERNATIONAL CORP SAN DIEGO CA
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| In spite of extensive prior research on the generation of seismic waves by underground nuclear explosions, it is still not possible to provide a complete explanation for the observed wavefields, particularly at regional distances. Spherically symmetric explosion models embedded in layered elastic media effectively model the P phases generated by explosions and the major characteristics of some reflected and transmitted phases. Nonlinear axisymmetric finite difference calculations of explosions, including gravity ... |
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| Synthetic Seismogram Study of the Eastern Central Andes |
30-Sep-2008 |
9 pages |
| Authors:
Estela Minaya; Evanz Lazaro; Percy Aliaga; Magaly Gonzalez; Wilfredo Cano; OBSERVATORIO SAN CALIXTO LA PAZ (BOLIVIA)
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| Along the South American coast, there have been several earthquakes of great magnitude--between 7.5 and 9.5 Mw, with ruptures 50 km to 950 km long, producing maximum intensities between VII and X (MM)-particularly in two seismic gaps located in southern Peru and northern Chile. In these places, two large earthquakes occurred in the 19th century, in 1868 and in 1877, establishing the possibility of the seismic gap hypothesis: earthquake hazard ... |
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| Initial Steps Toward Next-Generation, Waveform-Based, Three-Dimensional Models and Metrics to Improve Nuclear Explosion Monitoring in the Middle East |
30-Sep-2008 |
8 pages |
| Authors:
Brian Savage; Arthur J Rodgers; Jeroen Tromp; Brian Covellone; RHODE ISLAND UNIV KINGSTON
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| In an effort toward improving current seismic-velocity models for the Middle East, the initial Step of building a high-quality database of recordings from well characterized sources is essential. This high-quality database of recordings, or broadband waveforms, encompassing the region from the Mediterranean to the eastern edge of Tibet, will be the primary measure for evaluation and improvement in the iterative, waveform-based, adjoint-inversion process. Adjoint inversions, as with any waveform-based method, ... |
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| Expanding Coherent Array Processing to Larger Apertures Using Empirical Matched Field Processing |
30-Sep-2008 |
8 pages |
| Authors:
Frode Ringdal; Tormod Kvaerna; David B Harris; Steven J Gibbons; NORWEGIAN SEISMIC ARRAY (NORSAR) KJELLER
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| The objectives of this project are: (1) To investigate the limits of empirical matched field processing and other coherent array detection and parameter estimation methods as receiver aperture size increases from a few kilometers to many hundreds of kilometers. (2) To investigate techniques for extending the geographical source-region footprint over which empirical matched field processing and other coherent calibrated methods apply. Under a previous contract, we demonstrated the ability of ... |
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| Multi-Array Detection, Association and Location of Infrasound and Seismo-Acoustic Events in Utah |
30-Sep-2008 |
10 pages |
| Authors:
Brian Stump; Relu Burlacu; Chris Hayward; Stephen J Arrowsmith; Il-Young Che; Gurpreet Singh; LOS ALAMOS NATIONAL LAB NM
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| The two main objectives of this work are to (1) develop an automated method for processing seismic and infrasound data from multiple seismo-acoustic arrays, and (2) to apply the method to a regional network of arrays for validation. The project involves development of automated techniques for detecting, associating, and locating infrasound signals at single and multiple arrays and then combining the processed results with similar automated procedures for seismic signals. ... |
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| A New Regional 3-D Velocity Model for Asia from the Joint Inversion of P-Wave Travel Times and Surface-Wave Dispersion Data |
30-Sep-2008 |
10 pages |
| Authors:
Delaine T Reiter; William L Rodi; WESTON GEOPHYSICAL LEXINGTON MA
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| Accurate travel-time predictions for regional seismic phases are essential for locating small seismic events with the accuracy needed for nuclear monitoring decisions. Travel times calculated through a three-dimensional (3-D) Earth model have the best chance of achieving acceptable prediction errors, if the model is constrained by sufficient data. With this motivation, we have developed a self-consistent 3-D P and S velocity model of the crust and upper mantle in a ... |
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| Surface Wave Dispersion Measurements and Tomography from Ambient Seismic Noise Correlation in China |
30-Sep-2008 |
12 pages |
| Authors:
Zhen Xu; Xiaodong Song; Michael H Ritzwoller; Xinlei Sun; Sihua Zheng; Yingjie Yang; ILLINOIS UNIV AT URBANA-CHAMAPIGN
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| We perform ambient noise tomography of China using the data from the China National Seismic Network and global and PASSCAL stations. The results so far are summarized below. (1) Dispersion measurements and tomography. For most of the station pairs, we retrieve good Rayleigh waveforms from ambient noise correlations using 18 months of continuous data at all distance ranges across the entire region (over 5000 km) and for periods from 70 ... |
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| Shear Velocity Structure in NE China and Characterization of Infrasound Wave Propagation in the 1-210 Kilometer Range |
30-Sep-2008 |
11 pages |
| Authors:
Relu Burlacu; Chris Hayward; Kristine Pankow; Tae-Sung Kim; Brian W Stump; Rong-Mao Zhou; Yun-Tai Chen; Zhi-Xian Yang; Robert B Herrmann; SOUTHERN METHODIST UNIV DALLAS TX
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| We continued the operation of the Southern Methodist University-Institute of Geophysics, China Earthquake Administration (SMU-IGPCEA) broadband seismic network through May 2008 using Program for the Array Seismic Studies of the Continental Lithosphere (PASSCAL) instrumentation. The operating network included three stations northwest of Beijing and 10 stations in Xiuyan. Lisoning Province, NE China. At the end of May, the PASSCAL instrumentation was returned to the U.S. During the 5.5-year operation, we ... |
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| Finite-Frequency Seismic Tomography of Body Waves and Surface Waves from Ambient Seismic Noise: Crustal and Mantle Structure Beneath Eastern Eurasia |
30-Sep-2008 |
11 pages |
| Authors:
Wei Zhang; Xiaoping Yang; Yong Ren; Ting Yang; Yang Shen; SCIENCE APPLICATIONS INTERNATIONAL CORP SAN DIEGO CA
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| To improve seismic calibration for nuclear explosion monitoring, we use 3D sensitivity kernels of finite-frequency body and surface waves to develop models of the crustal and mantle structures beneath eastern Eurasia. We have collected and processed available broadband data from both permanent stations and temporary networks in eastern Eurasia. We obtained a regional P-wave velocity model for the mantle structures down to 1,500 km beneath the eastern Eurasia. We also ... |
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| Improvements to a Major Digital Archive of Seismic Waveforms from Nuclear Explosions: Borovoye Seismogram Archive |
30-Sep-2008 |
11 pages |
| Authors:
Won-Young Kim; Paul Richards; Howard Patton; George Randall; COLUMBIA UNIV PALISADES NY LAMONT-DOHERTY EARTH OBSERVATORY
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| We are in the second year of a three-year project to generate in modern form an easily usable archive of digital seismograms derived from regional waveforms recorded at the Borovoye Observatory (BRV), northern Kazakhstan, over a thirty-year period going back to 1966 and spanning the time when state-of-the-art sensors and dataloggers were introduced at this site by several different western groups. The BRV seismograms, which include multichannel regional signals from ... |
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| Estimating Local and Near-Regional Velocity and Attenuation Structure from Seismic Noise |
30-Sep-2008 |
11 pages |
| Authors:
Peter Gerstoft; Jian Zhang; William A Kuperman; Nick Harmon; Karim G Sabra; Michael C Fehler; Steven R Taylor; CALIFORNIA UNIV SAN DIEGO LA JOLLA
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| This paper investigates the utility of computing Time-Domain Green's Functions (TDGF) to be used for estimating velocity and attenuations structure for the purposes of nuclear explosion monitoring over local and near-regional distances. Our objective is to extend and apply the methodology of deriving TDGF for propagation between two receivers by cross correlation of seismic noise and/or coda of earthquakes observed at the receivers and concentrates on the following four tasks: ... |
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| Refined Local and Regional Seismic Velocity and Attenuation Models from Finite-Frequency Waveforms |
30-Sep-2008 |
11 pages |
| Authors:
Wei Zhang; Xiaoping Yang; Yang Shen; Li Zhao; SCIENCE APPLICATIONS INTERNATIONAL CORP SAN DIEGO CA
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| In seismic tomography, the reference or starting models are commonly one-dimensional (1D) and the structural sensitivity kernels of seismic data are calculated without considering the finiteness of seismic waves in both time and frequency domains. These simplifications result in a theoretical limit, in addition to that from the data coverage, on the structural resolution in tomography inversions. In small-scale (such as the crustal) structural imaging, however, a higher resolution is ... |
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| Seismic Source Scaling and Discrimination in Diverse Tectonic Environments |
30-Sep-2008 |
11 pages |
| Authors:
Katherine Murphy; Rachel E Abercrombie; Kevin Mayeda; William R Walter; Gisela M Viegas; BOSTON UNIV MA
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| The objectives of this study are to improve low-magnitude (concentrating on M2.5-5) regional seismic discrimination by performing a thorough investigation of earthquake source scaling using diverse, high-quality datasets from varied tectonic regions. Local-to-regional high-frequency discrimination requires an estimate of how earthquakes scale with size. Walter and Taylor (2002) developed the Magnitude and Distance Amplitude Corrections (MDAC) method to empirically account for these effects through regional calibration. The accuracy of these ... |
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| Seismic Tomography of the Arabian-Eurasian Collision Zone and Surrounding Areas |
30-Sep-2008 |
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| Authors:
Haijiang Zhang; M N Van der Toksoz; Robert D Hilst; Youshun Sun; Levent Gulen; Dogan Kalafat; Huseyin S Kuleli; Chang Li; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| The objectives of this study are to determine P- and S-wave velocity structures in the crust and upper mantle and to characterize seismic wave propagation in the Arabian-Eurasian collision zone and surrounding areas, including Iran, Arabia, Eastern Turkey, and the Caucasus. The Arabian-Eurasian plate boundary is a complex tectonic zone shaped by continent-continent collision processes. In recent years the number of seismic stations has increased greatly in the region because ... |
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| High-Resolution Seismic Velocity and Attenuation Models of the Caucasus-Caspian Region |
30-Sep-2008 |
10 pages |
| Authors:
Eric Sandvol; Michael Pasyanos; Robert Mellors; Rengin Gok; Gleb Skobeltsyn; Ugur Teoman; Tea Godoladze; SAN DIEGO STATE UNIV CA
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| The southwest edge of Eurasia is a tectonically and structurally complex region that includes the Caspian and Black Sea basins, the Caucasus Mountains, and the high plateaus south of the Caucasus. Using data from 25 broadband stations located in the region, new estimates of crustal and upper mantle thickness, velocity structure, and attenuation are being developed. Receiver functions have been determined for all stations. Depth to Moho is estimated using ... |
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| Analyses and Simulation of 3D Scattering Due to Heterogeneous Crustal Structure and Surface Topography on Regional Phases, Magnitude Discrimination |
30-Sep-2008 |
13 pages |
| Authors:
Arban Pitarka; Don V Helmberger; Sidao Ni; URS GROUP INC GAITHERSBURG MD
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| The main purpose of this study is the understanding of scattering and its effects through step-by-step numerical experiments and waveform modeling, with the goal of providing useful insights into ongoing research for the development of simple empirical models of scattering that can be used in reducing the scatter in measures of Lg and coda wave magnitude and for discrimination purposes as well. We are performing anelastic 3D finite-difference simulations of ... |
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| Improved Phase Characterization of Far-Regional Body Wave Arrivals in Central Asia |
30-Sep-2008 |
11 pages |
| Authors:
Delaine Reiter; Aaron Ferris; Anastasia Stroujkova; WESTON GEOPHYSICAL LEXINGTON MA
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| At far-regional and near-teleseismic distances the early body-wave coda contains information that is potentially useful to monitoring seismologists. However, waveforms from this distance range are typically under-utilized because of propagation complexities that cause significant difficulties in seismogram interpretation. For example, the first approx. 20 seconds of a far-regional seismogram often include multi-pathed arrivals caused by the interaction of the wavefield with upper mantle discontinuities at 220 km, 410 km and ... |
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| U.S. Deep-Sea Tsunameter Network Fully Operational |
Sep-2008 |
11 pages |
| Authors:
William Hansen; Douglas Maxwell; Shannon McArthur; Richard Bouchard; Ian Sears; Jack Higgs; Mark Webster; NATIONAL DATA BUOY CENTER STENNIS SPACE CENTER MS
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| In March 2008, the National Oceanic and Atmospheric Administration's (NOAA) National Data Buoy Center (NDBC) completed the deployment of the last of the 39-station network of deep-sea tsunameters. This effort was an integral part of the National Tsunami Hazard Mitigation Program. The Tsunami Program is part of a cooperative effort to save lives and protect property through hazard assessment, warning guidance, mitigation, research capabilities, and international coordination. NOAA's National Weather ... |
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| Oil and Gas Development in the Arctic Ocean -- Understanding the Legal and Regulatory Framework |
Sep-2008 |
7 pages |
| Authors:
Fatima Ahmad; Samuel Rauch; Mark Hodor; NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION SILVER SPRING MD
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| Oil and gas companies have been focusing their efforts and devoting substantial resources to the Arctic Ocean with the goal of extracting potentially large oil and gas resources. While the Arctic Region may provide significant sources of energy for the United States, industry and Federal regulatory agencies must consider the impact of increased development in the Arctic environment, which is currently experiencing deterioration of sea ice due to changing climactic ... |
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| Automap User's Guide 2008 |
01-Jul-2008 |
232 pages |
| Authors:
Jana Diesner; Kathleen M Carley; Dave Columbus; Matthew J DeReno; CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
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| AutoMap is software for computer-assisted Network Text Analysis (NTA). NTA encodes the links among words in a text and constructs a network of the linked words. AutoMap subsumes classical Content Analysis by analyzing the existence, frequencies, and covariance of terms and themes. |
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| Earthquakes: Risk, Monitoring, Notification, and Research |
19-Jun-2008 |
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| Authors:
Peter Folger; LIBRARY OF CONGRESS WASHINGTON DC CONGRESSIONAL RESEARCH SERVICE
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| Close to 75 million people in 39 states face some risk from earthquakes. Seismic hazards are greatest in the western United States, particularly California, Alaska, Washington, Oregon, and Hawaii. The Rocky Mountain region, a portion of the central United States known as the New Madrid Seismic Zone, and portions of the eastern seaboard, particularly South Carolina, also have a relatively high earthquake hazard. Compared to the loss of life in ... |
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| Model P Wave Multipathing at Regional Distances in Southeast Asia |
09-Jun-2008 |
88 pages |
| Authors:
Keith D Koper; Ali Fatehi; SAINT LOUIS UNIV MO DEPT OF EARTH AND ATMOSPHERIC SCIENCES
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| This report describes our analysis of seismograms recorded by the medium aperture array in Chiang Mai, Thailand (CMAR). There are two main topics covered in the report. One relates to array analysis of noise recorded over a ten year period. We document the directional characteristics of the noise as well as the seasonal variation in its amplitude. Most of this work is described in the appendix. The second topic involves ... |
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| Waveform Modeling of the Crust and Upper Mantle Using S, Sp, SsPmP, and Shear-Coupled PL Waves |
10-May-2008 |
48 pages |
| Authors:
Jay Pulliam; Mrinal K Sen; Abhijit Gangopadhyay; TEXAS UNIV AT AUSTIN INST FOR GEOPHYSICS
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| We developed a waveform modeling code that computes synthetic seismograms with a parallelized reflectivity method and fits the observed waveforms by global optimization. Assuming a 1-D, isotropic, layered Earth, our code computes synthetic seismograms for all layers, frequencies, and ray parameters. It implements a global optimization algorithm using Very Fast Simulated Annealing that allows for broad model space search so as to rind the global minimum, and hence minimizes dependency ... |
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| Near Source Energy Partitioning for Regional Waves in 2D and 3D Models |
30-Apr-2008 |
62 pages |
| Authors:
Ru-Shan Wu; Xiao-Bi Xie; Thome Lay; CALIFORNIA UNIV SANTA CRUZ
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| The complex excitation and energy partitioning mechanisms yielding regional phases are difficult to empirically separate by data analysis. Thus, numerical modeling approaches are valuable for investigating excitation and propagation of regional seismic phases. We use accurate full-wave simulations (2D and 3D finite-difference method, and 2D boundary element method) to calculate seismic wave excitation and propagation in near-source region. An embedded array slowness analysis is used for quantifying how energy will ... |
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| Spectral Studies of Shallow Earthquakes and Explosions: Implications for P/S Energy Partitioning, Stress Drop, and Discrimination |
16-Jan-2008 |
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| Authors:
Peter Shearer; Bettina Allmann; CALIFORNIA UNIV SAN DIEGO LA JOLLA INST OF GEOPHYSICS AND PLANETARY PHYSICS
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| We compute and analyze P-wave spectra from 18,101 earthquakes and 1770 explosions recorded by 196 broadband seismic stations in southern California at epicentral distances up to 100 km. We use an online waveform database stored on a RAID system at Caltech, which provides complete access to the Southern California Seismic Network (SCSN) seismogram archive. We compute spectra using 1.28s noise and signal windows, positioned immediately before and after the P ... |
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| Wave Scattering and Sensing Strategies in Intermittent Terrestrial Environments |
Jan-2008 |
9 pages |
| Authors:
D K Wilson; D E Lawson; D G Albert; M F Bigl; D Finnegan; V E Ostashev; G H Goedecke; ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH
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| This research has two main components: (1) a new, wavelet-based cascade model for intermittent (uneven) distributions of objects in terrestrial environments and (2) a complementary analysis of intermittent wave scattering. Taken together, these developments facilitate realistic statistical descriptions of the performance range (uncertainty) associated with sensing and communication systems. The wavelet cascade model uses a simple set of decay processes to generate complex random media with realistic organization of objects ... |
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| Embedment of the Sediment Layer Electrode Deployer (SLED): Results from 2006 Tests at Stennis Space Center |
21 SEP 2007 |
15 pages |
| Authors:
Andrew J. Quaid; Jeffrey W. Book; Mark S. Hulbert; NAVAL RESEARCH LAB STENNIS SPACE CENTER MS OCEAN SCIENCES BRANCH
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| In 2006, five field tests were made at Stennis Space Center of a Sediment Layer Electrode Deployer (SLED). The objective was to submerge an array of vertical-plate electrodes, with a total surface area of 18,580 cm squared into anoxic sediment layers by a method that may be accomplished from research vessels. The embedded electrodes would allow power generation from the Benthic Unattended Generator (BUG) technique. Towed-deployment and vibration-deployment techniques were ... |
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| Seismic Energy Generation and Partitioning into Various Regional Phases from Different Seismic Sources in the Middle East Region |
20 SEP 2007 |
85 pages |
| Authors:
Yefim Gitterman; Vladimir Pinsky; Rami Hofstetter; GEOPHYSICAL INST OF ISRAEL HOLON (ISRAEL)
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| The project was focused on studying, experimentally, features of seismic energy generation and partitioning of P and S waves from different explosive seismic sources, at near-source and regional distances, in the time and spectral domain. An extensive database of Ground Truth single-fired explosions was created. The explosions selected contain a broad variety of design features (buried and surface sources, tamped and decoupled shots, large diameter 0.5-0.8m borehole and near-spherical cavity ... |
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| The Physical Basis of the Explosion Source and Generation of Regional Seismic Phases |
31 AUG 2007 |
156 pages |
| Authors:
Jeffrey L. Stevens; G. E. Baker; Heming Xu; SCIENCE APPLICATIONS INTERNATIONAL CORP SAN DIEGO CA
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| The goal of this project is to understand explosion generation of shear waves. We quantify contribution of surface reflected pS, S*, scattered Rg, and S directly generated by non-spherical source elements to local and regional S-wave phases in high and low velocity source media through simulations and data analysis. Data include a large set of historical local records of Semipalatinsk nuclear explosions digitized for this project by Institute for the ... |
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| High-Resolution Seismic Velocity and Attenuation Structure of the Sichuan-Yunnan Region, Southwest China, Using Seismic Catalog and Waveform Data |
13 JUL 2007 |
62 pages |
| Authors:
Haijiang Zhang; Yunfeng Liu; Clifford H. Thurber; Zhen Xu; Xiaodong Song; WISCONSIN UNIV-MADISON
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| The Sichuan-Yunnan region in southwestern China lies in the transition zone between the uplifted Tibetan plateau to the west and the Yangtze continental platform to the east. This region has a very complicated geological structure and is one of the most active areas of continental earthquakes in the world. This two-year project is to develop high-resolution models of the velocity and attenuation structure of the Sichuan-Yunnan region (longitudes ~97-108 degrees ... |
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| Obtaining Unique, Comprehensive Deep Seismic Sounding Data Sets for CTBT Monitoring and Broad Seismological Studies |
02 JUL 2007 |
62 pages |
| Authors:
Igor B. Morozov; Elena A. Morozova; Scott B. Smithson; WYOMING UNIV LARAMIE DEPT OF GEOLOGY AND GEOPHYSICS
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| In cooperation with the Center for Geophysical and Geoecological Studies (GEON, Moscow, Russia), the University of Wyoming and now also with the University of Saskatchewan digitized, edited, transferred into standard digital formats, and delivered to public domain seismic records from 12 major Deep Seismic Sounding (DSS) projects acquired in 1970-1980's in the former Soviet Union. The data include 3-component records from 22 Peaceful Nuclear Explosions (PNEs) and over 500 chemical ... |
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| Seismic and Gravitational Studies of Melting in the Mantle's Thermal Boundary Layers |
JUN 2007 |
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| Authors:
Emily M. Van Ark; WOODS HOLE OCEANOGRAPHIC INSTITUTION MA
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| This thesis presents three studies which apply geophysical tools to the task of better understanding mantle melting phenomena at the upper and lower boundaries of the mantle. The first study uses seafloor bathymetry and small variations in the gravitational acceleration over the Hawaii-Emperor seamount chain to constrain the changes in the igneous production of the hot spot melting in the mantle which has created these structures over the past 80 ... |
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Seismology
