The October 20, 2012 earthquake
M5.3near San Lucas, California
A magnitude 5.3 earthquake 5.4 miles deep, centred in San Benito County. The 289th strongest in California’s record since 1900, and the strongest within 50 miles since a magnitude 6.0 on September 28, 2004. 8 aftershocks of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.3
- moment magnitude (mw)
- Depth
- 5.4 mi
- 8.6 km below the surface
- Local time
- Saturday, October 20, 2012
- 23:55 PDT; 06:55 UTC on Oct 21, 2012
- In California’s record
- 289th
- strongest of 97,065 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event nc71863625 (“24 km NE of San Lucas, California”). The USGS event page carries the ShakeMap, felt reports and the official summary.
Aftershocks
Earthquakes of magnitude 2.5 or more within 20 miles of the epicentre in the 30 days after.
8
Aftershocks in 30 days
3.6
Largest aftershock, Oct 21, 2012
4
On the first day
2
In the 7 days before
- The search radius is the surface rupture length expected for an earthquake of this magnitude (Wells and Coppersmith, 1994), at least 20 and at most 600 miles, so a great earthquake's sequence is counted along its whole fault.
Counties and cities within 50 miles
Distance from the epicentre to each county boundary (zero when inside) and to each city centre.
Counties
- San Benito CountyCA · inside
- Monterey CountyCA · 1.7 mi
- Fresno CountyCA · 9.7 mi
- Merced CountyCA · 30.0 mi
- Kings CountyCA · 41.0 mi
- Madera CountyCA · 42.5 mi
- San Luis Obispo CountyCA · 44.9 mi
- Santa Clara CountyCA · 49.2 mi
Cities, largest first
- HollisterCA · 48.3 mi
- Paso RoblesCA · 48.4 mi
- SoledadCA · 27.1 mi
- GreenfieldCA · 21.6 mi
- CoalingaCA · 31.3 mi
- King CityCA · 16.7 mi
- AvenalCA · 45.5 mi
- MendotaCA · 40.7 mi
Earthquakes around the epicentre
3,024 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.
Earlier earthquakes of magnitude 5 or more within 50 miles, strongest first
- May 2, 1983M6.7
- December 22, 2003M6.5
- March 2, 1901M6.4
- November 21, 1952M6.2
- May 25, 1905M6.1
- September 28, 2004M6.0
- April 8, 1961M5.9
- June 7, 1934M5.8
- July 25, 1926M5.8
- August 6, 1916M5.8
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.