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Title: The Source Physics Experiment Large N Array

Journal Article · · Seismological Research Letters
DOI: https://doi.org/10.1785/0220180072 · OSTI ID:1476701
 [1];  [1];  [1];  [1];  [1];  [1];  [2];  [2];  [3]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

To improve the understanding of S wave generation from an explosion, a temporary deployment of 996 geophones, including both one component (Z) and three component sensors (3C), was installed from April 15 to May 23, 2016 at the Nevada National Security Site (NNSS). Sensor spacing varied from 25 to 100 m and consisted of 500 Z and 496 3C 5-Hz geophones. Data were continuously recorded during the deployment at low-gain (0 db) from April 15 to April 28 and high-gain (36 db) from April 29 to May 23. A buried (76.5 m depth) 5035 kg TNT equivalent chemical explosion (SPE-5) was recorded on April 26. It was situated in a weathered granite body surrounded by volcanic tuffs, Paleozoic carbonates, and alluvium. The array was deployed approximately 400 to 3000 m from the explosion. A set of large weight-drop shots (13,000 kg source) at 53 locations both inside and outside the geophone array were also recorded, as were local, regional, and teleseismic earthquakes. Data recovery was good, with 95% of data recovered from the chemical explosion and up to 99% in the following weeks, including both the weightdrop shots campaign and the continuous data. Important initial results from the deployment include estimates of the spatial correlation length of velocity heterogeneities and a higher resolution velocity model. Observations of the data and synthetics, indicate that some far-field (elastic) S wave energy is generated by scattering and conversion outside the near-field (inelastic) region. Interferometric processing was conducted on a Hadoop ‘big-data’ cluster.

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:
1476701
Report Number(s):
LLNL--JRNL-746719; 931215
Journal Information:
Seismological Research Letters, Journal Name: Seismological Research Letters Journal Issue: 5 Vol. 89; ISSN 0895-0695
Publisher:
Seismological Society of AmericaCopyright Statement
Country of Publication:
United States
Language:
English