| Lithospheric Models of the Middle East to Improve Seismic Source Parameter Determination/Event Location Accuracy |
Sep 2012 |
10 pages |
| Authors:
Rengin Gok; Stephen Herzog; Keith Nakanishi; Michael E Pasyanos; Rob J Mellors; Arthur J Rodgers; David B Harris; Eileen S Vergino; LAWRENCE LIVERMORE NATIONAL LAB CA
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 | The Middle East is a tectonically complex and seismically active region. The ability to accurately locate earthquakes and other seismic events in this region is complicated by tectonics, the uneven distribution of natural earthquakes and the fact that countries run separate national seismic networks without well-developed data-sharing agreements. We report here on a variety of scientific efforts to enhance knowledge of the lithospheric velocity structure in the Middle East, making ... |
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| Analysis and Simulation of Far-Field Seismic Data from the Source Physics Experiment |
Sep 2012 |
12 pages |
| Authors:
Arben Pitarka; Robert J Mellors; Arthur J Rodgers; Sean R Ford; Phillip E Harben; Jeffery L Wagoner; William R Walter; Michael E Pasyanos; Anders petersson; Oleg Y Vorobiev; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The SPE-N is a series of chemical explosions intended to enhance our physical understanding and ability to quantitatively model seismic signals from explosions at the NNSS with the goal of improving our nuclear test monitoring capabilities (Brunish et al., 2010). The main objective is to develop comprehensive three-dimensional high fidelity modeling capabilities to enable a transition from the current empirically-based explosion monitoring approach, where accuracy hinges on the availability of ... |
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| Integrated Detection of Pathogens and Host Biomarkers for Wounds |
Apr 2012 |
14 pages |
| Authors:
Crystal Jaing Nicholas; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The increasing incidence and complications arising from combat wounds has necessitated a reassessment of methods for effective treatment. Infection, excessive inflammation, and incidence of drug-resistant organisms all contribute toward negative outcomes for afflicted individuals. The organisms and host processes involved in wound progression, however, are incompletely understood. We therefore set out, using our unique technical resources, to construct a profile of combat wounds which did or did not successfully resolve. ... |
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| Effect of Electric Fields of the Reaction Rates in Shock Initiating and Detonating Solid Explosives |
Jan 2012 |
6 pages |
| Authors:
Craig M Tarver; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The presence of a strong electric field has been demonstrated to effect the shock initiation and detonation wave propagation of solid high explosives. Several mechanisms have been proposed to explain the observed increased shock sensitivity, increased detonation velocity, and decreased failure diameter of certain explosives. The most likely chemical mechanism is postulated to be the excitation of some of the explosive molecules and/or intermediate reaction products to higher energy electronic ... |
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| Feasibility of Wide-Area Decontamination of Bacillus anthracis Spores Using a Germination-Lysis Approach |
16 Nov 2011 |
22 pages |
| Authors:
Staci Kane; Chris G Campbell; LAWRENCE LIVERMORE NATIONAL LAB CA
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| This presentation covered background and problem, spore resistance to decontamination, current solutions, the Germination-Lysis approach, proof of concept, germination rate, relative costs, potential for scale-up, and challenges and possible solutions. |
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| Fixatives Application for Risk Mitigation Following Contamination with a Biological Agent |
02 Nov 2011 |
21 pages |
| Authors:
Mark Sutton; Chris G Campbell; LAWRENCE LIVERMORE NATIONAL LAB CA
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| This presentation gave an overview of the use of fixatives for use after a biological event. The presentation provided background, problem, current solution, advantages of fixatives, examples for radiological application, risk mitigation and rapid return to service, relative cost, potential for scale up, and challenges and possible solutions. |
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| Germination-Lysis for Wide-Area Decontamination of Bacillus anthracis Spores |
01 Nov 2011 |
20 pages |
| Authors:
Staci Kane; Feliza Bourguet; Paul Jackson; Chris Campbell; ELLEN RABER; LAWRENCE LIVERMORE NATIONAL LAB CA
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| This presentation covered the use of a Germination-Lysis approach to decontamination of Bacillus anthracis spores, based on the fact that germinated spores are more susceptible to simple disinfection methods such as UV and desiccation. The presentation covered challenges to wide-area spore decontamination, challenges to germination-lysis decontamination, proof of concept, project focus, experimental approach, and the relative cost. |
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| Production of Neutrons up to 18 MeV in High-Intensity, Short-Pulse Laser Matter Interactions |
24 Oct 2011 |
6 pages |
| Authors:
D P Higginson; J M McNaney; D C Swift; G M Petrov; J Davis; J A Frenje; L C Jarrott; R Kodama; K L Lancaster; A J Mackinnon; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The generation of high-energy neutrons using laser-accelerated ions is demonstrated experimentally using the Titan laser with 360 J of laser energy in a 9 ps pulse. In this technique, a short-pulse, high-energy laser accelerates deuterons from a CD2 foil. These are incident on a LiF foil and subsequently create high energy neutrons through the 7Li(d,xn) nuclear reaction (Q=15 MeV). Radiochromic film and a Thomson parabola ion-spectrometer were used to diagnose ... |
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| Computing and Visualizing Reachable Volumes for Maneuvering Satellites |
Sep 2011 |
12 pages |
| Authors:
Ming Jiang; Willem H de Vries; Alexander J Pertica; Scot S Olivier; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Detecting and predicting maneuvering satellites is an important problem for Space Situational Awareness. The spatial envelope of all possible locations within reach of such a maneuvering satellite is known as the Reachable Volume (RV). As soon as custody of a satellite is lost, calculating the RV and its subsequent time evolution is a critical component in the rapid recovery of the satellite. In this paper, we present a Monte Carlo ... |
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| Analysis of Galaxy 15 Satellite Images from a Small-Aperture Telescope |
Sep 2011 |
10 pages |
| Authors:
Sergei Nikolaev; Don Phillion; Lance Simms; Alex Pertica; Scot S Olivier; Rita Cognion; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Galaxy 15, a geostationary telecommunications satellite, ceased responding to ground operators commands on April 5, 2010. The satellite went into eastward longitudinal drift interfering with operation of other geostationary satellites. Before and after the control of Galaxy 15 was re-established on December 27, 2010, some optical observations of the satellite were conducted using a small-aperture telescope, at sidereal tracking rate, to derive more accurate orbital parameters for Galaxy 15. Here ... |
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| The Updated LLNL-G3D Global P-Wave Velocity Model and Its Performance in Seismic Event Location |
Sep 2011 |
12 pages |
| Authors:
Nathan A Simmons; Stephen C Myers; Gardar Johannesson; Eric M Matzel; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The objective of this project is to generate a seamless model of the Earth s crust and mantle that is capable of accurately predicting regional and teleseismic travel times. The objective will further advance event monitoring capabilities, through self-consistent determination of seismic travel times that are necessary for accurate event location. The objective requires simultaneous modeling of detailed upper mantle heterogeneities to adequately predict regional phases such as Pn and ... |
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| Extending Regional Seismic Travel Time (RSTT) Tomography to New Regions |
Sep 2011 |
12 pages |
| Authors:
Stephen C Myers; Michael L Begnaud; Sanford Ballard; W S Phillips; Michael E Pasyanos; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Lowering the global seismic detection threshold can be accomplished by introducing data recorded at regional distances (2000 km from the event) into global monitoring systems. Unfortunately, introduction of regional data degrades average epicenter accuracy compared to locations constrained solely by data recorded at greater distances. Location accuracy degrades because regional seismic travel time (RSTT) prediction error is generally greater than prediction error for waves that travel to greater distances. In ... |
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| Improving Ground Motion Simulation Capabilities for Underground Explosion Monitoring: Coupling Hydrodynamic-to-Seismic Solvers and Studies of Emplacement Conditions |
Sep 2011 |
11 pages |
| Authors:
Arthur J Rodgers; Heming Xu; Ilya N Lomov; N A Petersson; Bjorn Sjogreen; Oleg Y Vorobiev; Veraun Chipman; LAWRENCE LIVERMORE NATIONAL LAB CA
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| This project involves research being performed to improve ground motion simulation capabilities for underground explosion monitoring. We are working along two thrusts: 1) we are coupling hydrodynamic (non-linear shock) and seismic (linear anelastic) wave propagation codes; and 2) we are investigating the effect of source emplacement conditions on ground motions. For both thrusts we are modeling explosion motions using GEODYN, an Eulerian hydrodynamic code developed at Lawrence Livermore National Laboratory ... |
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| Analysis and Simulation of Near-Field Wave Motion Data from the Source Physics Experiment Explosions |
Sep 2011 |
13 pages |
| Authors:
Tarabay H Antoun; Heming Xu; Oleg Y Vorobiev; Eric B Herbold; Lew A Glenn; Ilya N Lomov; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The Source Physics Experiment (SPE-N) at the Nevada National Security Site is planned as a series of chemical explosions under a variety of emplacement conditions. The goal of the SPE-N is to improve our physical understanding and ability to model explosively generated seismic waves, particularly S-waves. The first SPE explosion (SPE1) consisted of a 100 kg shot at a depth of 60 meters in granite (Climax Stock). The shot was ... |
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| Seismic Attenuation, Event Discrimination, Magnitude and Yield Estimation, and Capability Analysis |
Sep 2011 |
11 pages |
| Authors:
Michael E Pasyanos; William R Walter; Eric M Matzel; Rengin Gok; Douglas A Dodge; Sean R Ford; Arthur J Rodgers; LAWRENCE LIVERMORE NATIONAL LAB CA
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| We present the latest results on Lawrence Livermore National Laboratory's calibration efforts for seismic attenuation of regional body and surface waves that have application to many different areas of nuclear explosion monitoring. We have developed methods that use amplitude measurements of the direct regional phases (Pn, Pg, Sn Lg) to determine the attenuation structure of the lithosphere in Eurasia. The amplitudes are inverted simultaneously for attenuation parameters (Qp, Qs) of ... |
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| Toward an Empirically-Based Parametric Explosion Spectral Model |
Sep 2011 |
13 pages |
| Authors:
Sean R Ford; William R Walter; Stanley D Ruppert; Eric M Matzel; Teresa F Hauk; Rengin Gok; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Small underground nuclear explosions need to be confidently detected and identified in regions of the world where they have never before occurred. We are developing a parametric model of the nuclear explosion seismic source spectrum derived from regional phases (Pn, Pg, Sn, and Lg) that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model ... |
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| Analysis and Simulation of Far-Field Seismic Data from the Source Physics Experiment Explosions |
Sep 2011 |
12 pages |
| Authors:
Robert J Mellors; Arthur J Rodgers; Phillip E Harben; William R Walter; Sean Ford; Jeffery L Wagoner; N A Petersson; Bjorn A Sjogreen; Teresa F Hauk; Stan D Ruppert; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The Source Physics Experiment (SPE-N) at the Nevada National Security Site (NNSS) is planned as a series of chemical explosions under a variety of emplacement conditions. The SPE-N goal is to improve our physical understanding and ability to model how explosion generate seismic waves, particularly S-waves. The first SPE-N explosion (SPE1) occurred in May 2011 and consisted of a 220 lb (100 kg) chemical explosion at a depth of 180 ... |
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| Combining Analyst and Waveform-Correlation-Based Arrival Time Measurements in the Bayesloc Multiple-Event Location Algorithm |
Sep 2011 |
8 pages |
| Authors:
Stephen C Myers; Gardar Johannesson; Douglas A Dodge; Nathan A Simmons; LAWRENCE LIVERMORE NATIONAL LAB CA
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| We add relative arrival-time measurements that are derived from waveform correlation to the Bayesloc multiple-event location algorithm. Bayesloc is a formulation of joint probability over event locations, travel time corrections phase labels, and arrival-time measurement errors. The Bayesloc formulation is hierarchical with distinct statistical models for each component of the multiple-event system, including prior constraints for any of the parameters. Bayes' Theorem allows calculation of the joint probability for hypothesized ... |
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| Impact Response of US Army and National Football League Helmet Pad Systems |
04 Jan 2011 |
60 pages |
| Authors:
William C Moss; Michael J King; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Lawrence Livermore National Laboratory [LLNL] was tasked to compare the impact response of NFL helmet pad systems and U.S. Army pad systems compatible with an Advanced Combat Helmet [ACH] at impact velocities up to 20 ft/s. This was a one-year study funded by the U.S. Army and JIEDDO. The Army/JIEDDO point of contact is COL R. Todd Dombroski, DO, JIEDDO Surgeon. LLNL was chosen by committee to perform the research ... |
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| Exploiting Data Similarity to Reduce Memory Footprints |
Jan 2011 |
14 pages |
| Authors:
Susmit de Biswas; Bronis R Supinski; Martin Schulz; Diana Franklin; Timothy Sherwood; Frederic T Chong; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Memory size has long limited large-scale applications on high-performance computing (HPC) systems. Since compute nodes frequently do not have swap space, physical memory often limits problem sizes. Increasing core counts per chip and power density constraints, which limit the number of DIMMs per node, have exacerbated this problem. Further DRAM constitutes a significant portion of overall HPC system cost. Therefore, instead of adding more DRAM to the nodes, mechanisms to ... |
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| Fighting Fire with Fire: Modeling the Datacenter-Scale Effects of Targeted Superlattice Thermal Management |
Jan 2011 |
12 pages |
| Authors:
Susmit Biswas; Mohit Tiwari; Timothy Sherwood; Luke Theogarajan; Frederic T Chong; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Local thermal hot-spots in microprocessors lead to worstcase provisioning of global cooling resources, especially in large-scale systems. However, efficiency of cooling solutions degrade non-linearly with supply temperature, resulting in high power consumption and cost in cooling - 50100% of IT power. Recent advances in active cooling techniques have shown on-chip thermoelectric coolers (TECs) to be very efficient at selectively eliminating small hot-spots, where applying current to a superlattice film deposited ... |
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| The Challenge of Determining the Need for Remediation Following a Wide-Area Biological Release. Commentary |
Jan 2011 |
6 pages |
| Authors:
ELLEN RABER; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Recovering from a biological attack is a complex process requiring the successful resolution of numerous challenges. The Interagency Biological Restoration Demonstration program is one of the first multiagency efforts to develop strategies and tools that could be effective following a wide-area release of B. anthracis spores. Nevertheless, several key policy issues and associated science and technology issues still need to be addressed. For example, more refined risk assessment and management ... |
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| A Parallel, High-Fidelity Radar Model |
Sep 2010 |
12 pages |
| Authors:
Matthew Horsley; Benjamin Fasenfest; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Accurate modeling of Space Surveillance sensors is necessary for a variety of applications. Accurate models can be used to perform trade studies on sensor designs, locations, and scheduling. In addition, they can be used to predict system-level performance of the Space Surveillance Network to a collision or satellite break-up event. A high fidelity physics-based radar simulator has been developed for Space Surveillance applications. This simulator is designed in a modular ... |
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| Large-Scale Simulation of a Process for Cataloging Small Orbital Debris |
Sep 2010 |
11 pages |
| Authors:
Don Phillion; Alex Pertica; Ben Fasenfest; Matt De Horsley; Wim Vries; H K Springer; David Jefferson; Scot Olivier; Keric Hill; Chris Sahol; LAWRENCE LIVERMORE NATIONAL LAB CA
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| We demonstrate a methodology for establishing orbits for the abundant, un-catalogued, yet dangerous, small orbital debris that will become observable with planned improvements to the Space Fence. Although roughly 15,000 orbital objects are present in the SSN catalog, it is believed that at least 200,000 objects that are massive enough to cause significant damage are in Earth orbit. With improvements to the Space Fence, LEO debris down to 5 cm ... |
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| Enhancing Seismic Calibration Research Through Software Automation and Scientific Information Management |
Sep 2010 |
12 pages |
| Authors:
Douglas A Dodge; Michael D Ganzberger; Teresa F Hauk; Stanley D Ruppert; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Development (GNEMRD) Program at Lawrence Livermore National Laboratory (LLNL) continues to make significant progress enhancing the process of deriving seismic calibrations and performing scientific integration analysis, and information management with software automation tools. Our tool efforts address the problematic issues of very large datasets and varied formats encountered during seismic calibration research. New information management and analysis tools ... |
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| Calibration of Attenuation Structure in Eurasia to Improve Discrimination and Yield |
Sep 2010 |
11 pages |
| Authors:
Michael E Pasyanos; William R Walter; Eric Matzel; Sean R Ford; Rengin Gok; Arthur J Rodgers; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| It is well known that one-dimensional models do a poor job of predicting both regional amplitudes and travel-times over large and tectonically complicated regions. As a result regional discrimination methods (e.g., high-frequency P/S, Ms:mb) and magnitude estimates (e.g. coda magnitude) can perform poorly when applied over broad regions. The careful calibration of the earth's attenuation structure is critical to the universal application of event discrimination and yield estimation methods down ... |
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| Background Acoustic Noise Models for the IMS Hydroacoustic Stations |
Sep 2010 |
12 pages |
| Authors:
Philip E Harben; Terri F Hauk; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Background acoustic noise levels in the ocean have been increasing for the past several decades yet many of our hydroacoustic detection assessment tools use noise models based on data from the 60's and 70's. In some ocean basins, noise levels in the monitoring band (1-100 Hz) have risen 15 dB since the 1960's. To address this issue and provide accurate noise models at each of the six International Monitoring System ... |
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| A Regional Seismic Travel Time Model for North America |
Sep 2010 |
12 pages |
| Authors:
Stephen C Myers; Michael L Begnaud; Sanford Ballard; Abelardo L Ramirez; W S Phillips; Michael E Pasyanos; Harley Benz; Raymond P Buland; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Monitoring seismic events at ever-lower magnitude thresholds requires the utilization of seismic stations that are close to the event. The proliferation of seismic stations across the globe results in lower seismic detection thresholds because more stations are likely to be at regional distance to an event. However, utilization of arrival time data at regional distances often results in degraded location accuracy, because large variations in regional crust and upper-mantle structure ... |
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| Global-Scale P-Wave Tomography Designed for Accurate Prediction of Regional and Teleseismic Travel Times for Middle East Events |
Sep 2010 |
12 pages |
| Authors:
Nathan A Simmons; Stephen C Myers; Gardar Johannesson; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| A global-scale P-wave tomography model of the crust and mantle is constructed. The model depicts both large-scale tectonic/dynamic features, as well as detailed upper mantle heterogeneities beneath the greater Middle East region. Fully three-dimensional ray tracing is employed to achieve accurate travel-time predictions of a suite of P and Pn arrivals, necessitating the characterization of irregular and discontinuous boundaries. Therefore, we explicitly represent undulating seismic discontinuities in the crust and ... |
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| Toward an Empirically-Based Parametric Explosion Spectral Model |
Sep 2010 |
10 pages |
| Authors:
Sean R Ford; William R Walter; Stan D Ruppert; Eric Matzel; Terri F Hauk; Rengin Gok; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Small underground nuclear explosions need to be confidently detected and identified in regions of the world where they have never occurred. We are developing a parametric model of the nuclear explosion seismic source spectrum derived from regional phases (Pn, Pg, Sn, and Lg) that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that ... |
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| Bayesloc Multiple-Event Location Applied to a Global Data Set |
Sep 2010 |
11 pages |
| Authors:
Stephen C Myers; Gardar Johannesson; Nathan A Simmons; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Production of high-quality data sets for calibration of seismic travel times remains a painstaking and costly endeavor. The value of meticulous data analysis is beyond reproach, but the number and coverage of events with accurate locations and carefully measured seismic-phase arrival times is not sufficient for either development of high-fidelity (3-dimensional) models or comprehensive empirical calibration. Although regional and global bulletins of seismic data provide excellent data coverage, these databases ... |
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| Progress in Three-Dimensional Simulations of Explosions and Earthquakes |
Sep 2010 |
11 pages |
| Authors:
Arthur J Rodgers; Oleg Vorobiev; N A Petersson; Bjorn A Sjogreen; William Foxall; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Advances in numerical methods for modeling seismic wave excitation and propagation and ever more powerful parallel computers are making it easier to simulate ground motions on the scale lengths (domain sizes) and frequencies (resolutions) of importance to nuclear explosion monitoring. The objective of this research is to develop and improve methods for seismic simulation in fully 3D earth models to improve nuclear explosion monitoring. Specifically, research is directed along three ... |
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| Empirical and Theoretical Seismic Energy Partitioning from Explosions Under Different Confinement and Media Conditions |
Sep 2008 |
10 pages |
| Authors:
Jessie L Bonner; Brian W Stump; William R Walter; Xiaoning Yang; Mark R Leidig; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Some of the data-analysis results from the 2003 Arizona Source Phenomenology Experiments (SPE) were unexpected-explosions in slow-velocity limestone appear to be mainly isotropic under most emplacement conditions, while explosions in higher-velocity granite porphyry are marked by interesting source anisotropy. Even though the emplacement media were different, we did not expect to observe such prominent differences in the explosion phenomenology. While the SPE project was successfully completed, important questions remain regarding ... |
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| A Model and Methods for Regional Travel-Time Calculation |
Sep 2008 |
11 pages |
| Authors:
Stephen C Myers; Sanford Ballard; Charlotte A Rowe; Gregory S Wagner; Michael S Antolik; W S Phillips; Abe L Ramirez; Mike L Begnaud; Mike E Pasyanos; Doug A Dodge; Megan P Flanagan; Kevin D Hutchenson; Glenn T Barker; John J Dwyer; David R Russell; LAWRENCE LIVERMORE NATIONAL LAB CA
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| This project develops a model and methods for routine computation of regional travel times for crustal events anywhere on the globe. To improve on existing methods, the travel time calculations must capture the effect of the three-dimensional (3D) earth, yet the computation must be exceedingly efficient. We achieve global coverage by defining a seamless global tessellation of nodes with spacing of approximately 1 degree. Three-dimensional crustal structure is captured by ... |
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| Applications of a Next-Generation MDAC Discrimination Procedure Using Two-Dimensional Grids of Regional P/S Spectral Ratios |
Sep 2008 |
11 pages |
| Authors:
Mark D Fish; Steven R Taylor; Howard J Patton; William R Walter; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Using extensions of theoretical source models for earthquakes and explosions, Fisk (2006, 2007) provided a consistent model-based explanation of the frequency dependence of regional P/S discriminants at all major nuclear test sites as mainly due to larger systematic differences in P- and S-wave corner frequencies for explosions than earthquakes, as well as different spectral shapes. This project focuses on exploiting this new understanding to improve discrimination of earthquakes and explosions ... |
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| Seismic Simulations Using Parallel Computing and Three-Dimensional Earth Models to Improve Nuclear Explosion Phenomenology and Monitoring |
Sep 2008 |
11 pages |
| Authors:
Arthur J Rodgers; Eric Matzel; Micael E Pasyanos; Anders petersson; Bjorn A Sjogreen; Caroline Bono; Oleg Vorobiev; Tarabay H Antoun; Ilya N Lomov; William R Walter; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| The development of accurate numerical methods to simulate wave propagation in three-dimensional (3D) earth models and advances in computational power offer exciting possibilities for modeling the motions excited by underground nuclear explosions. This presentation will describe recent work to use new numerical techniques and parallel computing to model earthquakes and underground explosions to improve understanding of the wave excitation at the source and path-propagation effects. Firstly, we are using the ... |
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| Identifying Isotropic Events Using a Regional Moment Tensor Inversion |
Sep 2008 |
11 pages |
| Authors:
Sean R Ford; Douglas S Dreger; William R Walter; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| The deviatoric and isotropic source components for 17 explosions at the Nevada Test Site, as well as 12 earthquakes and 3 collapses in the surrounding region of the western US, are calculated using a regional time-domain full waveform inversion for the complete moment tensor. The events separate into specific populations according to their deviation from a pure double-couple and ratio of isotropic to deviatoric energy. The separation allows for anomalous ... |
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| Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration |
Sep 2008 |
11 pages |
| Authors:
Frode Ringdal; Steven J Gibbons; David B Harris; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Waveform correlation detectors compare a signal template with successive windows of a continuous data stream and report a detection when the correlation coefficient (CC), or some comparable detection statistic, exceeds a given threshold. Since these methods exploit characteristic details of the full waveform, they provide exquisitely sensitive detectors with far lower detection thresholds than typical STA/LTA algorithms. The drawback is that the form of the sought after signal needs to ... |
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| Enhancing Seismic Calibration Research Through Software Automation and Scientific Information Management |
Sep 2008 |
11 pages |
| Authors:
Stanley Ruppert; Douglas A Dodge; Michael D Ganzberger; Teresa F Hauk; Eric M Matzel; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Development (GNEMRD) Program at LLNL continues to make significant progress enhancing the process of deriving seismic calibrations and performing scientific integration, analysis, and information management with software automation tools. Our tool efforts address the problematic issues of very large datasets and varied formats encountered during seismic calibration research. New information management and analysis tools have resulted in demonstrated ... |
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| Regional Seismic Amplitude Modeling and Tomography for Earthquake-Explosion Discrimination |
Sep 2008 |
11 pages |
| Authors:
William R Walter; Michael B Pasyanos; Eric Matzel; Rengin Gok; Jerry J Sweeney; Sean R Ford; Arthur J Rodgers; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| We continue exploring methodologies to improve earthquake-explosion discrimination using regional amplitude ratios such as P/S in a variety of frequency bands. Empirically, we demonstrate that such ratios separate explosions from earthquakes, using closely located pairs of earthquakes and explosions recorded on common, publicly available stations at test sites around the world (e.g., Nevada, Novaya Zemlya, Semipalatinsk, Lop Nor, India, Pakistan, and North Korea). We are also examining if there is ... |
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| Attenuation Tomography of Northern California and the Yellow Sea/Korean Peninsula from Coda-Source Normalized and Direct LG Amplitudes |
Sep 2008 |
8 pages |
| Authors:
Sean R Ford; Douglas S Dreger; William S Phillips; William R Walter; Kevin Mayeda; Juca Malagnini; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Inversions for regional attenuation (1/Q) of Lg are performed in two different regions. The path attenuation component of the Lg spectrum is isolated using the coda-source normalization method, which corrects the Lg spectral amplitude for the source using the stable, coda-derived source spectra. Tomographic images of Northern California agree well with one-dimensional (1-D) Lg Q estimated from five different methods. We note that there is some tendency for tomographic smoothing ... |
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| PSA-Based Screening Outcomes, Dietary Heterocyclic Amine Exposure, and Prostate Cancer Risk in African Americans |
01-Jun-2008 |
74 pages |
| Authors:
Garrett A Keating; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Prostate cancer (PC) is the second leading cause of male U.S. cancer deaths, with African-Americans having the highest rate of PC mortality worldwide, as well as more abnormal results from screening tests that correlate with current or eventual PC. A 5-year prospective NIH-funded clinic-based study investigated whether prostate-specific antigen (PSA) and digital rectal exam (DRE) screening indicators of PC risk in 500 African-American men 50 to 70 years of age ... |
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| Numerical Experiments Investigating the Source of Explosion S-Waves |
Sep 2007 |
11 pages |
| Authors:
Stephen C Myers; Jeffrey L Wagoner; Shawn C Larsen; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| In this study we use validated explosion simulations to investigate the locations at which explosion S-waves originate. Several mechanisms for generating S-waves from an explosion source have been put forward. These mechanisms include tectonic release, non-symmetrical source effects, non-linear source effects, conversion of P-waves to S-waves off the free surface, and scattering of near-source Rayleigh waves. Each of these mechanisms is physically sound, and each mechanism likely contributes to the ... |
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| Regional Analysis of Lg Attenuation: Comparison of 1-D Methods in Northern California and Application to the Yellow Sea/Korean Peninsula |
Sep 2007 |
11 pages |
| Authors:
Sean R Ford; Douglas S Dreger; Kevin M Mayeda; William R Walter; Luca Malagnini; W S Phillips; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| The measurement of regional attenuation Q(1) can produce method dependent results. The discrepancies among methods are due to differing parameterizations (e.g., geometrical spreading rates), employed data sets (e.g., choice of path lengths and sources), and methodologies themselves (e.g., measurement in the frequency or time domain). We apply the coda normalization (CN), two-station (TS), reverse two-station (RTS), source-pair/receiver-pair (SPRP), and the new coda-source normalization (CS) methods to measure Q of the ... |
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| Considerations of the Use of 3-D Geophysical Models to Predict Test Ban Monitoring Observables |
Sep 2007 |
11 pages |
| Authors:
David B Harris; John J Zucca; David McCallen; Michael E Pasyanos; Megan P Flanagan; Stephen C Myers; William R Walter; Arthur J Rodgers; Phil E Harben; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| The use of 3-D geophysical models to predict nuclear test ban monitoring observables (phase travel times, amplitudes, dispersion, etc.) is widely anticipated to provide improvements in the basic seismic monitoring functions of detection, association, location, discrimination and yield estimation. A number of questions arise when contemplating a transition from 1-D, 2-D and 2.5-D models to constructing and using 3-D models, among them: (1) Can a 3-D geophysical model or a ... |
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| Advanced Waveform Simulation for Seismic Monitoring Events |
Sep 2007 |
12 pages |
| Authors:
Don V Helmberger; Jeroen Tromp; Arthur J Rodgers; LAWRENCE LIVERMORE NATIONAL LAB CA
|
| Comprehensive nuclear-test-ban monitoring in terms of location and discrimination has progressed significantly in recent years. However, the characterization of sources and the estimation of low yields remains a particular challenge. As the recent Korean shot demonstrated, we can probably expect to have a small set of teleseismic, far-regional and high-frequency regional data to analyze in estimating the yield of an event. Since stacking helps to bring signals out of the ... |
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| Extension of the Caucasus Seismic Information Network Study into Central Asia |
Sep 2007 |
11 pages |
| Authors:
Randolph J Martin; Mary L Krasovec; Spring A Romer; William Foxall; Eileen S Vergino; Levent Gulen; M N Toksoz; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The Central Asian Seismic Research Initiative (CASRI) is an extension of the Caucasus Seismic Information Network (CauSIN). Both projects seek to build knowledge bases of geological, geophysical, and seismic information in their respective regions and to use crustal modeling techniques to create a combined model of the regions to aid in seismic monitoring. Catalog and phase arrival data from local networks in the CASRI region (Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan) ... |
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| Developing and Exploiting a Unique Seismic Data Set from South African Gold Mines for Source Characterization and Wave Propagation |
Sep 2007 |
11 pages |
| Authors:
Andrew A Nyblade; William R Walter; Rengin Gok; Lindsay Linzer; Ray Durrheim; LAWRENCE LIVERMORE NATIONAL LAB CA
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| In this project, we are developing and exploiting a unique seismic data set to address the characteristics of small seismic events and the associated seismic signals observed at local ( 200 km) and regional ( 2000 km) distances. The data set is being developed using mining-induced events from 3 deep gold mines in South Africa recorded on in-mine networks ( 1 km) comprised of hundreds of high-frequency sensors, a network ... |
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| Adaptive Waveform Correlation Detectors for Arrays: Algorithms for Autonomous Calibration |
Sep 2007 |
11 pages |
| Authors:
Frode Ringdal; Steven J Gibbons; David B Harris; LAWRENCE LIVERMORE NATIONAL LAB CA
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| Waveform correlation detectors compare a signal template with successive windows of a continuous data stream and report a detection when the correlation coefficient, or some comparable detection statistic, exceeds a given threshold. Since these methods exploit characteristic details of the full waveform, they provide exquisitely sensitive detectors with far lower detection thresholds than typical short-term average/long-term average (STA/LTA) algorithms. The drawback is that the form of the sought-after signal needs ... |
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| Empirical Observations of Earthquake-Explosion Discrimination Using P/S Ratios and Implications for the Sources of Explosion S-Waves |
Sep 2007 |
11 pages |
| Authors:
William R Walter; Eric Matzel; Michael E Pasyanos; David B Harris; Rengin Gok; Sean R Ford; LAWRENCE LIVERMORE NATIONAL LAB CA
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| We continue exploring methodologies to improve earthquake-explosion discrimination using regional amplitude ratios such as P/S (ratio of P- and/or S-wave energy). The earliest simple source models predicted P/S wave amplitudes for explosions should be much larger than for earthquakes across the body wave spectrum. However empirical observations show the separation of explosions from earthquakes using regional P/S amplitudes is strongly frequency dependent, with relatively poor separation at low frequencies (tilde ... |
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