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2017 seismic imaging of the West Napa Fault Zone, St. Helena, California

In April 2017, the U.S. Geological Survey acquired high resolution P- and S-wave seismic data across the suspected trace of the West Napa Fault zone in St. Helena, California. We acquired seismic reflection, refraction, and guided-wave data along a 215-m-long profile across the expected trend of the West Napa Fault zone. To acquire the reflection and refraction data, we co-located shots and geophones, spaced every 2 m along the profile. We used 109 SercelTM L40A P-wave (40-Hz vertical-component) geophones with a sensitivity of 22.34 volts/meter/second to record 108 P-wave shots, and 109 SercelTM L28-LBH S-wave (4.5-Hz horizontal-component) geophones with a sensitivity of 31.3 volts/meter/second to record 108 S-wave shots. We generated P-wave data using one of two active sources depending on site accessibility: a 226-kg accelerated weight drop (AWD) and a 3.5-kg sledgehammer and steel plate combination. S-wave sources were generated by horizontally striking an aluminum block with a 3.5-kg sledgehammer. We acquired fault zone guided wave data by generating P- (AWD) and S-wave (angle AWD) energy approximately 225 m north of the P- and S-wave recording arrays. All data were recorded using two 60-channel Geometrics Stratavisor NX-60TM seismographs with a 24-bit analog-to-digital converter with a roll-along descaling factor (Subcommittee of the SEG Engineering and Groundwater Geophysics Committee, 1990); the seismographs were connected to the P- and S-wave geophones via refraction cables. Each shot was recorded for two seconds, with data recording starting 100 ms before the actual time of the shot. Data were recorded at a sampling rate of 0.5 ms, or 2000 samples per second. This report provides the metadata needed to utilize the seismic data. Reference: Subcommittee of the SEG Engineering and Groundwater Geophysics Committee, Pullan, S. E., Chairman, 1990, Recommended standard for seismic (/radar) data files in the personal computer environment: Geophysics, vol. 55, no. 9, p. 1260-1271.

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Author(s) Joanne H Chan orcid, Rufus D Catchings orcid, Belle E Philibosian orcid, Mark R Goldman orcid, Coyn J Criley, Robert R Sickler orcid, Stephen B DeLong orcid
Publication Date 2018
Beginning Date of Data 2017-04-11
Ending Date of Data 2017-04-11
Data Contact
DOI https://doi.org/10.5066/P9LKXZKP
Citation Chan, J.H., Catchings, R.D., Philibosian, B.E., Goldman, M.R., Criley, C.J., Sickler, R.R., and DeLong, S.B., 2018, 2017 seismic imaging of the West Napa Fault Zone, St. Helena, California: U.S. Geological Survey data release, https://doi.org/10.5066/P9LKXZKP.
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Metadata Date 2020-08-27
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Citations of these data No citations of these data are known at this time.
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License http://www.usa.gov/publicdomain/label/1.0/
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Harvest Source: ScienceBase
Harvest Date: 2024-07-29T04:01:24.000Z