The March 9, 1931 earthquake

M5.6near the coast of Northern California

A magnitude 5.6 earthquake, 38.2 miles off Humboldt County. The 160th strongest in California’s record since 1900, and the strongest within 50 miles since a magnitude 5.8 on April 28, 1923.

The earthquake

Magnitude: 5.6; surface-wave magnitude (ms)
Depth: —; Not recorded
Local time: Monday, March 9, 1931; 19:28 PST; 03:28 UTC on Mar 10, 1931
Epicentre: 40.00°N, 125.00°W; 38.2 mi from Humboldt County
In California’s record: 160th; strongest of 97,065 since 1900
Within 50 miles: 1; county; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event ushis867 (“near the coast of Northern California”). 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 · 38.2 mi

Earthquakes around the epicentre

2,012 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.