The October 28, 1909 earthquake

M6.0Near Rio Dell, California

A magnitude 6.0 earthquake, centred in Humboldt County. The 66th strongest in California’s record since 1900, and the strongest within 50 miles since a magnitude 6.4 on April 23, 1906.

The earthquake

Magnitude: 6.0; moment magnitude (mw)
Depth: —; Not recorded
Local time: Thursday, October 28, 1909; 22:45 PST; 06:45 UTC on Oct 29, 1909
Epicentre: 40.50°N, 124.20°W; In Humboldt County
In California’s record: 66th; strongest of 97,065 since 1900
Within 50 miles: 3; counties; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event ushis495 (“Near Rio Dell, 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 · inside
Mendocino CountyCA · 35.7 mi
Trinity CountyCA · 38.1 mi

Cities, largest first

EurekaCA · 20.7 mi
ArcataCA · 25.9 mi
FortunaCA · 6.7 mi

Earthquakes around the epicentre

2,354 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
August 18, 1908M5.8

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