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Title: Generation of Shear Motion from an Isotropic Explosion Source by Scattering in Heterogeneous Media

Abstract

One challenging task in explosion seismology is the development of physical models for explaining the generation of S waves during underground explosions. Recent analysis of ground motion from chemical explosions during the Source Physics Experiment (Pitarka et al., 2015) suggests that, although a large component of shear motion was generated directly at the source, additional scattering from heterogeneous velocity structure and topography is necessary to better match the recorded data. In our paper, we used a stochastic representation of small-scale velocity variability to produce high-frequency scattering and to analyze its implication on shear-motion generation during underground explosions. In our stochastic velocity model, the key parameters that affect scattering are the correlation length and the relative amplitude of velocity perturbations. Finally, based on finite-difference simulations of elastic wave propagation from an isotropic explosion source, we find that higher velocity perturbations result in larger shear motion, whereas the correlation length, which controls the scatterers size, affects the frequency range at which relative transverse motion is larger.

Authors:
 [1];  [1];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1375999
Report Number(s):
LLNL-JRNL-676939
Journal ID: ISSN 0037-1106
Grant/Contract Number:
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Bulletin of the Seismological Society of America
Additional Journal Information:
Journal Volume: 106; Journal Issue: 5; Journal ID: ISSN 0037-1106
Publisher:
Seismological Society of America
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION

Citation Formats

Hirakawa, Evan, Pitarka, Arben, and Mellors, Robert. Generation of Shear Motion from an Isotropic Explosion Source by Scattering in Heterogeneous Media. United States: N. p., 2016. Web. doi:10.1785/0120150243.
Hirakawa, Evan, Pitarka, Arben, & Mellors, Robert. Generation of Shear Motion from an Isotropic Explosion Source by Scattering in Heterogeneous Media. United States. doi:10.1785/0120150243.
Hirakawa, Evan, Pitarka, Arben, and Mellors, Robert. Tue . "Generation of Shear Motion from an Isotropic Explosion Source by Scattering in Heterogeneous Media". United States. doi:10.1785/0120150243. https://www.osti.gov/servlets/purl/1375999.
@article{osti_1375999,
title = {Generation of Shear Motion from an Isotropic Explosion Source by Scattering in Heterogeneous Media},
author = {Hirakawa, Evan and Pitarka, Arben and Mellors, Robert},
abstractNote = {One challenging task in explosion seismology is the development of physical models for explaining the generation of S waves during underground explosions. Recent analysis of ground motion from chemical explosions during the Source Physics Experiment (Pitarka et al., 2015) suggests that, although a large component of shear motion was generated directly at the source, additional scattering from heterogeneous velocity structure and topography is necessary to better match the recorded data. In our paper, we used a stochastic representation of small-scale velocity variability to produce high-frequency scattering and to analyze its implication on shear-motion generation during underground explosions. In our stochastic velocity model, the key parameters that affect scattering are the correlation length and the relative amplitude of velocity perturbations. Finally, based on finite-difference simulations of elastic wave propagation from an isotropic explosion source, we find that higher velocity perturbations result in larger shear motion, whereas the correlation length, which controls the scatterers size, affects the frequency range at which relative transverse motion is larger.},
doi = {10.1785/0120150243},
journal = {Bulletin of the Seismological Society of America},
number = 5,
volume = 106,
place = {United States},
year = {Tue Jul 19 00:00:00 EDT 2016},
month = {Tue Jul 19 00:00:00 EDT 2016}
}

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Cited by: 2works
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