Title: Seismic moment tensor event screening

Journal Article · · Geophysical Journal International
DOI: https://doi.org/10.1093/gji/ggz578 · OSTI ID:1642481
 [1];  [2];  [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Array Information Technology, Inc., Melbourne, FL (United States)
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Event screening is an explosion monitoring practice that aims to identify an event as an explosion (‘screened in’) or not (‘screened out’). Confidence in event screening can be increased if multiple independent approaches are used. In this work, we describe a new approach to event screening using the seismic moment tensor and its representation on the hypersphere, specifically the 5-sphere of 6-degree unit vectors representing the normalized symmetric moment tensor. The sample of moment tensors from an explosion data set is unimodal on the 5-sphere and can be parametrized by the Langevin distribution, which is sometimes referred to as the Normal distribution on the hypersphere. Screening is then accomplished by finding the angle from the explosion population mean to any newly measured moment tensor and testing if that angle is in the tail of the Langevin distribution (conservatively quantified as greater than 99.9 per cent of the cumulative density). We apply the screen to a sample of earthquakes from the Western USA and the September 2017 explosion and subsequent collapse at the Pungyye-Ri Test Site in North Korea. All the earthquakes and the collapse screen out, but the explosion does not.

Research Organization:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
Grant/Contract Number:
AC52-07NA27344
OSTI ID:
1642481
Report Number(s):
LLNL-JRNL-662377; LLNL-JRNL-723095; LLNL-JRNL-758729; LLNL-JRNL-804110; 992927
Journal Information:
Geophysical Journal International, Journal Name: Geophysical Journal International Journal Issue: 1 Vol. 221; ISSN 0956-540X
Publisher:
Oxford University PressCopyright Statement
Country of Publication:
United States
Language:
English

References (17)

Experimental Seismic Event-screening Criteria at the Prototype International Data Center journal February 2002
Regional distance seismic moment tensors of nuclear explosions journal October 2002
Identifying isotropic events using a regional moment tensor inversion: ISOTROPIC EVENTS journal January 2009
Estimation of Full Moment Tensors, Including Uncertainties, for Nuclear Explosions, Volcanic Events, and Earthquakes journal June 2018
Source type plot for inversion of the moment tensor journal January 1989
Simulation of the von mises fisher distribution journal January 1994
A uniform parametrization of moment tensors journal July 2015
A confidence parameter for seismic moment tensors journal February 2016
Volume in moment tensor space in terms of distance journal April 2017
Optimal estimation of scalar seismic moment journal September 1982
Cluster analysis of seismic moment tensor orientations journal December 1993
Stable inversions for complete moment tensors journal August 2008
A geometric setting for moment tensors: A geometric setting for moment tensors journal May 2012
Source Parameters of Eastern California and Western Nevada Earthquakes from Regional Moment Tensor Inversion journal February 2003
mb:Ms Event Screening Revisited journal February 2012
Moment Tensor Source‐Type Analysis for the Democratic People’s Republic of Korea–Declared Nuclear Explosions (2006–2017) and 3 September 2017 Collapse Event journal September 2018
Statistical inference of Langevin distribution for directional data journal January 1996

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58 GEOSCIENCES
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