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Title: Earthquake stress via event ratio levels: Application to the 2011 and 2016 Oklahoma seismic sequences

Here, we develop a new methodology for determining earthquake stress drop and apparent stress values via spectral ratio asymptotic levels. With sufficient bandwidth, the stress ratio for a pair of events can be directly related to these low- and high-frequency levels. This avoids the need to assume a particular spectral model and derive stress drop from cubed corner frequency measures. The method can be applied to spectral ratios for any pair of closely related earthquakes and is particularly well suited for coda envelope methods that provide good azimuthally averaged, point-source measures. We apply the new method to the 2011 Prague and 2016 Pawnee earthquake sequences in Oklahoma. The sequences show stress scaling with size and depth, with the largest events having apparent stress levels near 1 MPa and smaller and/or shallower events having systematically lower stress values.
ORCiD logo [1] ; ORCiD logo [2] ; ORCiD logo [3] ; ORCiD logo [1]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Weston Geophysical Corp., Lexington, MA (United States)
  3. Univ. of California, Berkeley, CA (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0094-8276
Grant/Contract Number:
AC52-07NA27344; LLNL-JRNL-714167
Published Article
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 44; Journal Issue: 7; Journal ID: ISSN 0094-8276
American Geophysical Union
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
Country of Publication:
United States
58 GEOSCIENCES; earthquake apparent stress; earthquake scaling; Oklahoma seismicity
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1351641; OSTI ID: 1410068