Two-Dimensional Finite-Difference Modeling of Broadband Regional Wave Propagation Phenomena [electronic resource] : Validation of Regional Three-Dimensional Earth Models and Prediction of Anomalous Regional Phases.
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| Online Access: |
Online Access (via OSTI) |
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| Format: | Government Document Electronic eBook |
| Language: | English |
| Published: |
Washington, D.C. : Oak Ridge, Tenn. :
United States. Department of Energy. ; distributed by the Office of Scientific and Technical Information, U.S. Department of Energy,
2000.
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| Abstract: | An important challenge for seismic monitoring of nuclear explosions at low magnitude to verify a nuclear-test-ban treaty is the development of techniques that use regional phases for detection, location, and identification. In order to use such phases, region-specific earth models and tools are needed that accurately predict features such as travel times, amplitudes, and spectral characteristics. In this paper, we present our efforts to use two-dimensional finite-difference modeling to help develop and validate regional earth models for the Middle East and North Africa and to develop predictive algorithms for identifying anomalous regional phases. To help develop and validate a model for the Middle East and North Africa, we compare data and finite-difference simulations for selected regions. We show that the proposed three-dimensional regional model is a significant improvement over standard one-dimensional models by comparing features of broadband data and simulations and differences between observed and predicted features such as narrow-band group velocities. We show how a potential trade-off between source and structure can be avoided by constraining source parameters such as depth, mechanism, and moment/source-time function with independent data. We also present numerous observations of anomalous timing and amplitude of regional phases and show how incorporation of two-dimensional structure can explain many of these observations. Based on these observations, and the predictive capability of our simulations, we develop a simple model that can accurately predict the timing of such phases. |
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| Item Description: | Published through SciTech Connect. 07/18/2000. "ucrl-jc-138992" 22nd Annual Department of Defense/Department of Energy Seismic Research Symposium, New Orleans, LA, Sep 12 - Sep 15, 2000. Goldstein, P; Ryall, F D; Pasyanos, M E; Schultz, C A; Walter, W R. |
| Physical Description: | 12p : digital, PDF file. |