The January 15, 1930 earthquake
M5.2near Big Bear Lake, California
A magnitude 5.2 earthquake, centred in San Bernardino County. The 305th strongest in California’s record since 1900, and the strongest within 50 miles since a magnitude 6.2 on July 22, 1923. 1 aftershock of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.2
- surface-wave magnitude (ms)
- Depth
- —
- Not recorded
- Local time
- Wednesday, January 15, 1930
- 16:24 PST; 00:24 UTC on Jan 16, 1930
- In California’s record
- 305th
- strongest of 97,065 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event ushis834 (“4 km SSE of Big Bear Lake, 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.
1
Aftershocks in 30 days
5.1
Largest aftershock, Jan 16, 1930 · its page
1
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 Bernardino CountyCA · inside
- Riverside CountyCA · 11.6 mi
- Los Angeles CountyCA · 43.1 mi
- Orange CountyCA · 47.5 mi
Cities, largest first
- RiversideCA · 33.5 mi
- San BernardinoCA · 22.9 mi
- FontanaCA · 32.8 mi
- Moreno ValleyCA · 25.9 mi
- OntarioCA · 41.9 mi
- Rancho CucamongaCA · 38.4 mi
- CoronaCA · 44.7 mi
- VictorvilleCA · 34.4 mi
- MenifeeCA · 38.8 mi
- MurrietaCA · 46.4 mi
- Jurupa ValleyCA · 35.2 mi
- RialtoCA · 28.5 mi
Earthquakes around the epicentre
3,179 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
- April 21, 1918M6.7
- July 22, 1923M6.2
- May 15, 1910M6.0
- September 19, 1907M5.3
- September 26, 1929M5.1
- April 10, 1910M5.0
- May 12, 1910M5.0
- June 6, 1918M5.0
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.