The January 22, 1923 earthquake

M7.1Humboldt County, California

A magnitude 7.1 earthquake 9.3 miles deep, 33.0 miles off Humboldt County. The 6th strongest in California’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900.

The earthquake

Magnitude: 7.1; moment magnitude (mw)
Depth: 9.3 mi; 15.0 km below the surface
Local time: Monday, January 22, 1923; 01:04 PST; 09:04 UTC
Epicentre: 40.48°N, 125.03°W; 33.0 mi from Humboldt County
In California’s record: 6th; strongest of 97,065 since 1900
Within 50 miles: 1; county; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event iscgem911261 (“The 1923 Humboldt County, California Earthquake”). The USGS event page carries the ShakeMap, felt reports and the official summary.

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 · 33.0 mi

Cities, largest first

FortunaCA · 47.4 mi

Earthquakes around the epicentre

2,340 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

USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.