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Title: Ground Motion Response to a ML 4.3 Earthquake Using Co-Located Distributed Acoustic Sensing and Seismometer Arrays

The PoroTomo research team deployed two arrays of seismic sensors in a natural laboratory at Brady Hot Springs, Nevada in March 2016. The 1500 m (length) by 500 m (width) by 400 m (depth) volume of the laboratory overlies a geothermal reservoir. The surface Distributed Acoustic Sensing (DAS) array consisted of 8700 m of fiber-optic cable in a shallow trench, including 340 m in a well. The conventional seismometer array consisted of 238 three- component geophones. The DAS cable was laid out in three parallel zig-zag lines with line segments approximately 100 meters in length and geophones were spaced at approximately 60- meter intervals. Both DAS and conventional geophones recorded continuously over 15 days during which a moderate-sized earthquake with a local magnitude of 4.3 was recorded on March 21, 2016. Its epicenter was approximately 150-km south-southeast of the laboratory. Several DAS line segments with co-located geophone stations were used to compare signal-to-noise (SNR) ratios in both time and frequency domains and to test relationships between DAS and geophone data. The ratios were typically within a factor of five of each other with DAS SNR often greater for P-wave but smaller for S-wave relative to geophone SNR. The SNRs measuredmore » for an earthquake can be better than for active sources, because the earthquake signal contains more low frequency energy and the noise level is also lower at those lower frequencies. Amplitudes of the sum of several DAS strain-rate waveforms matched the finite difference of two geophone waveforms reasonably well, as did the amplitudes of DAS strain waveforms with particle-velocity waveforms recorded by geophones. Similar agreement was found between DAS and geophone observations and synthetic strain seismograms. In conclusion, the combination of good SNR in the seismic frequency band, high-spatial density, large N, and highly accurate time control among individual sensors suggests that DAS arrays have potential to assume a role in earthquake seismology.« less
ORCiD logo [1] ;  [2] ;  [3] ;  [4] ;  [1] ;  [1] ;  [5]
  1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Geoscience
  2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Geoscience; Chinese Academy of Sciences, Wuhan (China). State Key Lab. of Geodesy and Earth's Dynamics and Inst. of Geodesy and Geophysics
  3. Silixa Ltd., Hertfordshire (United Kingdom); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Earth Resource Lab.
  4. Univ. of Wisconsin, Madison, WI (United States). Geological Engineering and Dept. of Civil and Environmental Engineering
  5. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Atmospheric, Earth, and Energy Division
Publication Date:
Grant/Contract Number:
EE0006760; AC52-07NA27344R
Accepted Manuscript
Journal Name:
Geophysical Journal International
Additional Journal Information:
Journal Volume: none; Journal Issue: none; Journal ID: ISSN 0956-540X
Oxford University Press
Research Org:
Univ. of Wisconsin, Madison, WI (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Geothermal Technologies Office (EE-4G); Univ. of Utah, Salt Lake City, UT (United States); Univ. of Oregon, Eugene, OR (United States); Univ. of Texas, El Paso, TX (United States); Silixa Ltd., Hertfordshire (United Kingdom); Ormat Technologies Inc., Reno, NV (United States); Chinese Academy of Sciences
Country of Publication:
United States
15 GEOTHERMAL ENERGY; 47 OTHER INSTRUMENTATION; Distributed Acoustic Sensing (DAS); ground motion; strain; particle velocity; 60 signal-to-noise ratio; earthquake seismology
OSTI Identifier: