The July 14, 1918 earthquake

M6.5near Big Lagoon, California

A magnitude 6.5 earthquake 9.3 miles deep, 31.8 miles off Humboldt County. The 24th strongest in California’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900.

The earthquake

Magnitude: 6.5; moment magnitude (mw)
Depth: 9.3 mi; 15.0 km below the surface
Local time: Sunday, July 14, 1918; 17:23 PDT; 00:23 UTC on Jul 15, 1918
Epicentre: 41.33°N, 124.72°W; 31.8 mi from Humboldt County
In California’s record: 24th; strongest of 97,065 since 1900
Within 50 miles: 2; counties; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event iscgem913200 (“52 km WNW of Big Lagoon, 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 · 31.8 mi
Del Norte CountyCA · 35.3 mi

Cities, largest first

EurekaCA · 46.9 mi
ArcataCA · 46.4 mi

Earthquakes around the epicentre

374 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 23, 1906M6.4

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