The January 1, 2023 earthquake
M5.3near Rio Dell, CA
A magnitude 5.3 earthquake 19.0 miles deep, centred in Humboldt County. The 258th strongest in California’s record since 1900, and the strongest within 50 miles since a magnitude 6.4 on December 20, 2022. 4 aftershocks of magnitude 2.5 or more followed within 30 days.
The earthquake
- Magnitude
- 5.3
- moment magnitude (mw)
- Depth
- 19.0 mi
- 30.6 km below the surface
- Local time
- Sunday, January 1, 2023
- 10:35 PST; 18:35 UTC
- In California’s record
- 258th
- strongest of 97,065 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event nc73827571 (“15km SE of Rio Dell, 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.
4
Aftershocks in 30 days
3.2
Largest aftershock, Jan 27, 2023
0
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
- Humboldt CountyCA · inside
- Mendocino CountyCA · 28.3 mi
- Trinity CountyCA · 31.8 mi
- Shasta CountyCA · 47.9 mi
- Tehama CountyCA · 48.4 mi
Earthquakes around the epicentre
2,019 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 25, 1992M7.2
- April 26, 1992M6.6
- January 9, 2010M6.5
- June 6, 1932M6.5
- April 26, 1992M6.5
- April 23, 1906M6.4
- December 21, 1954M6.4
- December 20, 2022M6.4
- December 20, 2021M6.2
- October 7, 1951M6.0
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.