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In November 2016, the U.S. Geological Survey acquired high-resolution P- and S-wave seismic data across the surface trace of the West Napa Fault zone near Buhman Avenue in Napa, California. We acquired seismic reflection, refraction, and guided-wave data along a 117-m-long profile across the known surface rupture zone of the West Napa Fault zone. To acquire the reflection and refraction data, we co-located shots and geophones, spaced every meter along the profile. We used 118 SercelTM L40A P-wave (40-Hz vertical-component) geophones with a sensitivity of 22.34 volts/meter/second to record 118 P-wave shots. We also used 118 SercelTM L28-LBH S-wave (4.5-Hz horizontal-component) geophones with a sensitivity of 31.3...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Earthquake Hazards,
Earthquakes,
Faulting (geologic),
Geophysics,
Napa,
These data include observations of liquefaction from ten earthquakes. The data are provided as a feature collection in a GeoJSON file format. Individual features are either points or polygons. Each feature has a single attribute called "earthquake" which gives the name and year of the earthquake associated with the liquefaction feature.
This page contains results from analysis of 2020 Maacama earthquake sequence, including the detected and relocated earthquake catalog along with associated focal mechanisms and preferred fault planes as derived in: Shelly, D. R., R. J. Skoumal, and J. L. Hardebeck, Fracture-mesh faulting in the swarm-like 2020 Maacama sequence revealed by high-precision earthquake detection, location, and focal mechanisms, Geophysical Research Letters, in review. File DS1. CSV file containing relocated hypocentroids (3520 events) Format: yyyy MM dd HH mm ss.sss lat(deg) lon(deg) dep(km) x(m) y(m) z(m) mag event_ID yyyy MM dd HH mm ss.sss: origin time year, month, day, hour, min, second) lat(deg) lon(deg) dep(km): relocated...
Seismic hazard assessments depend on an accurate prediction of ground motion, which in turn depends on a base knowledge of three-dimensional variations in density, seismic velocity, and attenuation. The datasets here are components of a National Crustal Model that couples geologic characteristics and geophysical parameters using a physical theoretical foundation combined with measured data for calibration. The model is intended to be internally consistent and seamless on a national scale; care is also taken to maximize consistency with existing regional models. An initial version of the model components are defined for the western U.S. on a 1-km grid. While the current focus of this effort is on improving estimates...
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...
Categories: Data;
Types: Map Service,
OGC WFS Layer,
OGC WMS Layer,
OGC WMS Service;
Tags: Geophysics,
Northern California,
Saint Helena,
Seismology,
USGS Science Data Catalog (SDC),
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