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Scientists Deploy Seismographs in Napa Valley

August 11, 2016

Media Advisory: Photo Opportunity

As the second anniversary of the August 24, 2014 South Napa earthquake approaches, U.S. Geological Survey scientists and volunteers, along with faculty and students from California State University, East Bay are planning an experiment to visualize the subsurface in and around the City of Napa and measure how the ground responds to earthquake shaking in different neighborhoods.

Hundreds of small portable seismographs will be temporarily set out along lines that cross the West Napa Fault zone and most of the Napa Valley. The data gathered will help characterize the underground geology around the West Napa Fault and the Napa Valley in three dimensions. This type of seismic survey can yield information that helps characterize localized shaking effects during an earthquake, and can help the community prepare for future earthquakes.

Very small explosive “bangs” set off at the bottom of 20-30-foot-deep drill holes allows seismic energy (tiny artificial quakes) to travel through the subsurface geological layers, allowing researchers to gather information about these layers that can’t easily be learned any other way. These tiny artificial earthquakes can only be felt if one is standing within a few feet of the drill hole.

Please RSVP to Susan Garcia or Leslie Gordon, so we know how many to expect.


Rufus Catchings, USGS geophysicist and project chief.

Luther Strayer, CSUEB professor of geology.

Coyn Criley, USGS science technician.

David Graves, resident host for one of the instruments.


Watch USGS scientists and volunteers deploy seismic sensors. See what the instruments look like, and learn how they work. Learn from scientists about the upcoming experiment, and what they hope to learn from it.


Wednesday, August 17, 2016, 11:30 a.m. PDT


459 Randolf Street, Napa, California

This is a private residence. Please respect the neighbors.


Throughout August and early September, USGS scientists and volunteers will be in Napa-area neighborhoods, surveying locations to place the seismic instruments that will record the tiny explosions. Actual deployment of the instruments is planned to be during the last week of August and early September. The USGS field crew will be wearing USGS identification and will be traveling in vehicles with clearly visible USGS logo placards.


satellite image of Napa Valley, showing urbanized area surrounded by green hills
Satellite image of the Napa Valley in California. Gray area is the City of Napa. Thin pink lines along the west side of the city are surface rupture traces of the West Napa Fault that broke during the August 24, 2014 earthquake. The two lines of red and yellow stars are locations of temporary seismographs that will be deployed for the 2016 survey. Two short turquoise-colored lines crossing the West Napa fault are locations where temporary seismographs were placed in 2014 to record aftershocks.

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