| Analyses of Near-Field and Near-Regional Signals from the Black Thunder Mine |
FEB 1998 |
52 pages |
| Authors:
Terrance G. Barker; Keith L. McLaughlin; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
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 | In this report we present analyses of seismic data recorded at the Black Thunder coal strip mine in the Powder River Basin of Wyoming. The data (collected by Stump et al, 1996) are a set of recordings at distances of a few kilometers from mining activity at that mine. Our objective was to determine whether these near-field data revealed features of quarry blasting that were ... |
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| Identification Performance of the IMS in the Middle East and North Africa |
JAN 1998 |
49 pages |
| Authors:
Terrance G. Barker; G. E. Baker; Keith L. McLaughlin; MAXWELL TECHNOLOGIES INC SAN DIEGO CA FEDERAL DIV
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| We have simulated the detection and identification performance of the proposed seismic network of the International Monitoring System (IMS) in the Middle East/North Africa. Figure 1 shows a map of Africa and western Eurasia with the proposed IMS alpha stations and the area for which the simulations were done. The identification performance of a network is strongly dependent upon regional source and propagation variability. However, knowledge of ... |
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| The Physical Basis for the Lg/P Discriminant: Signal Characteristics and Modeling |
NOV 1997 |
98 pages |
| Authors:
Theron J. Bennett; Keith L. McLaughlin; Ronald W. Cook; Jerry A. Carter; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
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| Effective monitoring of the Comprehensive Test Ban Treaty (CTBT) for low-magnitude events can only be achieved through the use of regional seismic observations. One of the most widely heralded regional discrimination techniques is based on the measurement of Lg/P ratios at regional seismic stations. Although this technique seems to separate events of different source types in many geographic regions, the physical basis for the discriminant and the significance of regional ... |
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| Advances in Numerical Methods |
SEP 97 |
65 pages |
| Authors:
Keith L. McLaughlin; B. Shkoller; D. E. Wilkins; T. G. Barker; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
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| This report summarizes work conducted over a two year period to improve numerical methods. The report has three main sections. Section 2 covers work on synthetics for layered earth models. Section 3 reports on three- dimensional (3D) elastic finite difference calculations and the relationship between one-dimensional (1D) (layered earth) and 3D laterally heterogeneous wavefields. Section 4 reports on development of a finite difference program to model the response of permeable ... |
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| The Physical Basis for the Lg/P Discriminant: General Properties and Preliminary Modeling |
MAR 1997 |
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| Authors:
Theron J. Bennett; Keith L. McLaughlin; Margaret E. Marshall; Jeffry L. Stevens; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
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 | A critical problem for reliable implementation of regional discrimination is incomplete understanding of how regional seismic signals depend on physical characteristics of the source and propagation path to the recording station. This research is directed at improving understanding of effects of these characteristics on an important regional discriminant, the Lg/P ratio. An empirical element in this research program has aimed at describing behavior of Lg/P ratios and their dependence on ... |
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| The Physical Basis for the Lg/P Discriminant: General Properties and Preliminary Modeling |
MAR 1997 |
56 pages |
| Authors:
Theron J. Bennett; Keith L. McLaughlin; Margaret E. Marshall; Jeffry L. Stevens; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
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| A critical problem for reliable implementation of regional discrimination is incomplete understanding of how regional seismic signals depend on physical characteristics of the source and propagation path to the recording station. This research is directed at improving understanding of effects of these characteristics on an important regional discriminant, the Lg/P ratio. An empirical element in this research program has aimed at describing behavior of Lg/P ratios and their dependence on ... |
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| Wavenumber Integration Synthetic Seismogram Calculations Using a Parallel Virtual Machine |
JUL 96 |
28 pages |
| Authors:
Keith L. McLaughlin; Boris Shkoller; MAXWELL TECHNOLOGIES INC SAN DIEGO CA FEDERAL DIV
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| The principal objectives of this work are to: (1) provide more accurate, and efficient means to compute, store, and retrieve synthetic seismograms for reference layered Earth structures and (2) examine limitations of using layered Earth structures to model principal features of regional seismograms in the presence of lateral heterogeneity. This annual report describes work completed in the first year of this two year project and very briefly describes work to ... |
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| Investigations of the Seismic Discrimination of Rockbursts |
JUL 96 |
69 pages |
| Authors:
Theron J. Bennett; Margaret E. Marshall; Brian W. Barker; Keith L. McLaughlin; John R. Murphy; MAXWELL TECHNOLOGIES INC SAN DIEGO CA
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| Our principal objective in this research has been to identify and test regional discrimination measures which can help facilitate the identification of the numerous rockbursts which are likely to be encountered in CTBT monitoring. We have reviewed characteristics of rockburst mechanisms and their seismic signals for a variety of different mining, tectonic, and propagation environments; and we have discovered several problem areas for rockburst discrimination. Our recent investigations have been ... |
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| Investigations of the Seismic Characteristics of Rockbursts |
DEC 95 |
89 pages |
| Authors:
Theron J. Bennett; Keith L. McLaughlin; Margaret E. Marshall; Brian W. Barker; John R. Murphy; S-CUBED LA JOLLA CA
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| This research is directed at improving understanding of rockbursts and related mine tremors as seismic sources and at distinguishing them from other source types based on characteristics of their signals. In addition, this effort seeks to gain insight into controllability of rockbursts and its relevance to possible clandestine testing of small nuclear explosions. An observational element of this research has focused on identifying the characteristics of the seismic signals from ... |
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| Numerical Simulation of Quarry Blast Sources |
01 JAN 94 |
25 pages |
| Authors:
Keith L. McLaughlin; T. G. Barker; J. L. Stevens; S-CUBED LA JOLLA CA
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| This final report summarizes the principal results of numerical investigations of the quarry blast as a seismic source. The goal was to derive simple but physically meaningful models that could be used to predict regional and teleseismic waveforms for large industrial blasts. The source models may then be used to develop seismic discrimination strategies for the identification of industrial blasts and other natural and man made seismic sources. Physical models ... |
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| Development of a Comprehensive Seismic Yield Estimation System for Underground Nuclear Explosions |
MAY 93 |
117 pages |
| Authors:
Jack R. Murphy; Jeffrey L. Stevens; D. C. O'Neill; B. W. Barker; Keith L. McLaughlin; S-CUBED LA JOLLA CA
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| This report summarizes the research which has been carried out in conjunction with the development of a comprehensive new seismic yield estimation system (YES) for underground nuclear explosions. Specifically, it provides a detailed description of the final version of YES which has been implemented at the ARPA Center for Seismic Studies (CSS) to estimate seismic yields of explosions at the Shagan River and Novaya Zemlya test sites of the former ... |
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| Seismic Source Representation for Spall |
21 NOV 90 |
16 pages |
| Authors:
Steven M. Day; Keith L. McLaughlin; SCRIPPS INSTITUTION OF OCEANOGRAPHY LA JOLLA CA
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| Spall may be a significant secondary source of seismic waves from underground explosions. The proper representation of spall as a seismic source is important for forward and inverse modeling of explosions for yield estimation and discrimination studies. We present a new derivation of a widely used point force representation for spall, which is based on a horizontal tension crack model. The derivation clarifies the relationship between point force and moment ... |
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| Finite-Difference Modeling of Rayleigh Wave Scattering and P-SV(Lg) Coupling Problems |
MAR 88 |
66 pages |
| Authors:
Rong-Song Jih; Keith L. McLaughlin; TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
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| The work has focused on the effects on near-source heterogeneity upon seismic wave scattering and phase conversions. The basic tool was a developing 2-dimensional explicit linear finite-difference code. By use of various initial conditions and/or the principle of reciprocity. One can generate the teleseismic response of the Earth model to a general seismic source. The propagation of Pn/ Sn/Rg phases with some Arctic paths are also modeled without using the ... |
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| Investigation of Explosion Generated SV Lg Waves in 2-D Heterogeneous Crustal Models by Finite-Difference Method |
FEB 88 |
77 pages |
| Authors:
Rong-Song Jih; Keith L. McLaughlin; TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
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| A linear finite-difference (FD) method was used to compare the excitation of far-field P- and SV-waves generated by shallow dilatational sources in a suite of heterogeneous 2-D crustal models. The crustal models tested included simple layered structures, media with random velocity perturbations having Gaussian or self-similar autocorrelation functions, media with rough or gentle topography generated by Markov chains, and laminated media with sinusoidal folds. The numerical experiments were conducted by ... |
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| Finite-Difference Simulations of Rayleigh-Wave Scattering by Shallow Heterogeneity |
NOV 87 |
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| Authors:
Keith L. McLaughlin; Rong-Song Jih; TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
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| Rayleigh waves normally incident upon 2-D shallow heterogeneity are simulated by the linear finite-difference method to study attenuation, transmission, and reflection of Rayleigh waves and to measure the Rayleigh-to-P and -SV body wave conversion. Transmission, reflection, and scattering depend on the depth, average scale size of the heterogeneity and the amplitude of the spatial fluctuation of velocity. As expected, larger spatial variation in velocity attenuates Rayleigh waves more than smooth ... |
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| Propagation and Excitation of Lg, Sn, and P-Pn Waves from Eastern United States Earthquakes by Regression Analysis of RSTN Data. Seismic Attenuation Studies at United Kingdom Arrays |
MAY 87 |
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| Authors:
John H. Goncz; William C. Dean; Zoltan A. Der; Alison C. Lees; Keith L. McLaughlin; TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
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| By applying regression analysis to amplitudes of the regional phases, pn, sn and lg in various frequency ranges we have derived the attenuation rates, extrapolated source spectra, and relative site responses for these phases in eastern north america using RSTN data. Observed regional phase amplitudes are modeled with three parameters. The estimates source excitation levels for all three phases exhibit high-frequency falloff rates between 1/f-sq-2 and 1/f-cubed -3 and have ... |
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| Finite-Difference Modeling of Seismological Problems in Magnitude Estimation Using Body Waves, Surface Waves and Seismic Source Imaging |
MAR 87 |
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| Authors:
Keith L. McLaughlin; Zoltan A. Der; Rong-Song Jih; Alison C. Lees; Lisa M. Anderson; TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
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| Contents: Boundary Conditions for Arbitrary Polygonal Topography in a 2-D Elastic Finite-Difference Scheme for Seismogram Generation; Teleseismic Spectral and Temporal M sub 0 and Psi sub infinity Estimates for four French Explosions in Southern Sahara; Scattering from Near-Source Topography: Teleseismic Observations and Numerical 2-D Explosive Line Source Simulations; Effects of Local Geologic Structure on Yucca Flats, NTS, Explosion Waveforms: 2- Dimensional Linear Finite Difference Simulations; Finite-Difference Simulations of Rayleigh Wave ... |
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| The Effects of Near-Source Topography on Explosion Waveforms: Teleseismic Observations and Linear Finite Difference Calculations |
JUL 86 |
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| Authors:
Keith L. McLaughlin; Rong-Song Jih; Zoltan A. Der; Alison C. Lees; TELEDYNE GEOTECH ALEXANDRIA VA ALEXANDRIA LABS
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| This report consists of three papers: Boundary Conditions for Arbitrary Polygonal Topography in a 2-D Elastic Finite-difference Scheme for Seismogram Generation; Teleseismic Spectral and Temporal Explosion Moment and Reduced Displacement Potential Estimates for Four French Explosions in Southern Sahara; Scattering from Near-Source Topography -- Teleseismic Observations and Numerical 2-D Explosive Line Source Simulations; Keywords: Primary seismic waves, Deconvolution; Two dimensional; Seismic data; Ahaggar Plateau. |
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Reports by Author
