Written by Shelley Olds, Christine Puskas, and Kathleen Hodgkinson
25 August 2014
Updated 26 September 2014
From the USGS Event Page:
A Mw 6.0 earthquake with its epicenter located 6 km (4 miles) northwest of American Canyon, California and 8 km (5 miles) south southwest of Napa, California, occurred at 3:20 a.m. PDT on August 24, 2014 at a depth of 11.3 km. See the ShakeMap (Figure 1) for a representation of ground shaking produced. The earthquake lies within the San Andreas Fault system. The San Andreas Fault forms the boundary between the North American and Pacific tectonic plates. As the Pacific plate moves to the northwest, relative to North America, deformation occurs between the major faults in the System. The region of this earthquake has a high probability of strong shaking in the future.
As published by the Northern California Seismic System (NCSS), like most earthquakes, the recent earthquake is expected to be followed by numerous aftershocks. Aftershocks are additional earthquakes that occur after the mainshock and in the same geographic area. See the Current Aftershock Warning. Most likely, the recent mainshock will be the largest in the sequence. At this time (3 days after the mainshock) the probability of a strong and possibly damaging aftershock M5 or larger IN THE NEXT 7 DAYS is approximately 11 PERCENT. However, there is a small chance (APPROXIMATELY 2 PERCENT) of an earthquake equal to or larger than this mainshock in the next 7 days. In addition, approximately 1 to 10 SMALL AFTERSHOCKS M3 - M5 are expected in the same 7-DAY PERIOD and may be felt locally.
The Earthquake Early Warning test system provided five seconds of warning to Berkeley, San Francisco, and areas farther south. No warning would have been possible within 20 miles of the earthquake.
For more information, see the USGS Earthquake Hazards Program Event Page.
In response to the 24 August 2014 Mw 6.0 South Napa, California earthquake, UNAVCO is currently downloading data recorded at five-samples-per-second (5 sps) for the full 24 hour UTC day of the event, and one-sample-per-second (1 sps) data for 3 days before and 3 days after the earthquake (7 days total). The downloaded files will be available from the UNAVCO ftp site. Update 08/26/2014: The 5 sps rinex data is now available from ftp://data-out.unavco.org/pub/highrate/5-Hz/rinex/2014/236/.
UNAVCO also produced a fully processed 1-sps borehole strainmeter (BSM) dataset spanning the time period of this event (Figure 3), available from the PBO borehole strainmeter download page. Nearest BSM stations are shown in Figure 4. For an interactive site map, see PBO BSM Station Location Map.
Last modified: 2020-02-06 00:23:16 America/Denver