The November 15, 1956 earthquake
M5.0near King City, CA
A magnitude 5.0 earthquake 3.7 miles deep, centred in San Benito County. The 451st strongest in California’s record since 1900, and the strongest within 50 miles since a magnitude 5.0 on July 29, 1951. 1 aftershock of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.0
- local magnitude (ml)
- Depth
- 3.7 mi
- 6.0 km below the surface
- Local time
- Thursday, November 15, 1956
- 19:23 PST; 03:23 UTC on Nov 16, 1956
- In California’s record
- 451st
- strongest of 97,065 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event ci3295741 (“28km NE of King City, CA”). 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.
1
Aftershocks in 30 days
4.2
Largest aftershock, Dec 11, 1956
0
On the first day
0
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.
- Before the modern seismic networks of the 1970s many small aftershocks went unrecorded, so early sequences read short.
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 · 4.9 mi
- Fresno CountyCA · 12.6 mi
- Merced CountyCA · 25.3 mi
- Madera CountyCA · 40.2 mi
- Santa Clara CountyCA · 44.4 mi
- Kings CountyCA · 45.4 mi
- San Luis Obispo CountyCA · 47.7 mi
Earthquakes around the epicentre
3,118 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
- March 2, 1901M6.4
- May 25, 1905M6.1
- June 7, 1934M5.8
- July 25, 1926M5.8
- August 6, 1916M5.8
- June 24, 1939M5.5
- October 5, 1920M5.2
- December 28, 1939M5.2
- December 3, 1931M5.1
- June 7, 1934M5.1
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.