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Filters: Tags: seismic refraction methods (X) > Types: OGC WFS Layer (X)

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The U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the Frijoles Fault strand of the San Gregorio Fault Zone (SGFZ) at northern Año Nuevo, California in 2012. SGFZ is a right-lateral fault system that is mainly offshore, and prior studies provide highly variable slip estimates, which indicates uncertainty about the seismic hazard it poses. Therefore, the primary goal of the seismic survey was to better understand the structure and geometry of the onshore section of the Frijoles Fault strand of the SGFZ. We deployed 118 geophones (channels) at 5-m spacing along a linear profile centered on the mapped surface trace of the Frijoles Fault and co-located active P- and S-wave sources...
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In August 2017, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data near six Southern California Seismic Network (SCSN) recording stations in southern California: CI.OLI Olinda; CI.SRN Serrano; CI.MUR Murrieta; CI.LCG La Cienega; CI.RUS Rush; and CI.STC Santa Clara (Figure 1). These strong-motion recording stations are located inside Southern California Edison electrical substations, critical infrastructures that provide essential services to millions of customers. The primary goals of the seismic survey were to understand the potential for amplified ground shaking and to evaluate lateral variability in shear-wave velocity at these sites. We deployed up to 88 geophones at 2-m or 4-m...
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Compressional- (P-) wave seismic refraction data were acquired in December 2018 and July 2019 along fourteen profiles within the spillway of Success Dam in Porterville, California. A new concrete ogee weir is planned for construction within the existing spillway, and the P-wave seismic velocity models will be used to inform further geotechnical investigations, including siting new geologic borings, and the advanced engineering design phases in terms of rock rippability and relative rock hardness/competency. Data acquisition, processing, and modeling were conducted collaboratively between the U.S. Geological Survey (USGS) and U.S. Army Corps of Engineers (USACE) Sacramento District. Data were acquired with Geometrics...
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In May 2019, the U.S. Geological Survey acquired high resolution P- and S-wave seismic data near six seismic network recording stations in San Bernardino County, California: Southern California Seismic Network CI.CLT Calelectic, CI.MLS Mira Loma, CI.CJM Cajon Mountain and CI.HLN Highland; California Strong Motion Instrumentation Program station CE.23542; and US National Strong-Motion Network station NP.5326 (Figure 1). The primary goals of the seismic survey were to better understand the potential for amplified ground shaking, to evaluate lateral variability in shear-wave velocity, and to calculate Vs30 at these sites. We deployed up to 67 DTCC SmartSolo 3-component seismometer systems ("nodes") at 2-m spacing...
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In September 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, approximately 70 m north of the previous seismic survey conducted in April 2017 (Chan et al., 2018). We acquired seismic reflection, refraction, and guided-wave data along a 75-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 1 and 2 m along the profile. We used 77 SercelTM L40A P-wave (40-Hz vertical-component) geophones with a sensitivity of 22.34 volts/meter/second to record 60 P-wave shots, and 77 SercelTM L28-LBH S-wave...
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In September 2021, the U.S. Geological Survey acquired high-resolution P- and S-wave data near seismic station CE.57213 in Fremont, California, approximately 100 m east of the mapped trace of the Hayward Fault. We acquired the seismic data to evaluate the time-averaged shear-wave velocity in the upper 30 m (VS30) and to better understand ground-shaking near the station CE.57213. The seismic data were acquired using a linear array of SmartSolo 3-component nodal seismometers (nodes), which continuously recorded at 2000 samples per second (0.5-ms sampling rate). We deployed 60 nodes, spaced at 2-m increments, along a 180-m-long, northeast-southwest-trending linear array. We generated P-wave seismic sources (shots)...
    map background search result map search result map 2017b high resolution seismic imaging of the West Napa Fault Zone, St. Helena, California Success Dam spillway seismic refraction survey, Porterville, California, December 2018 and July 2019 High-resolution seismic data acquired at six Southern California Seismic Network (SCSN) recording stations in 2017 High-resolution seismic data acquired at six seismic network recording stations in San Bernardino County, California in 2019 High-resolution seismic data acquired at northern Año Nuevo, California High-resolution seismic data acquired near seismic station CE.57213 in Fremont, California 2017b high resolution seismic imaging of the West Napa Fault Zone, St. Helena, California High-resolution seismic data acquired near seismic station CE.57213 in Fremont, California Success Dam spillway seismic refraction survey, Porterville, California, December 2018 and July 2019 High-resolution seismic data acquired at northern Año Nuevo, California High-resolution seismic data acquired at six seismic network recording stations in San Bernardino County, California in 2019 High-resolution seismic data acquired at six Southern California Seismic Network (SCSN) recording stations in 2017