The May 15, 1909 earthquake

M5.4Northeastern Montana

A magnitude 5.4 earthquake, centred in Daniels County. The 16th strongest in Montana’s record since 1900, and the strongest within 50 miles in the catalogue, which runs from 1900.

The earthquake

Magnitude: 5.4; as reported (mint)
Depth: —; Not recorded
Local time: Saturday, May 15, 1909; 21:15 MST; 04:15 UTC on May 16, 1909
Epicentre: 48.81°N, 105.38°W; In Daniels County
In Montana’s record: 16th; strongest of 1,459 since 1900
Within 50 miles: 6; counties; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event official19090516041500000 (“Northeastern Montana”). 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

Daniels CountyMT · inside
Sheridan CountyMT · 16.2 mi
Valley CountyMT · 25.8 mi
Roosevelt CountyMT · 25.8 mi
McCone CountyMT · 49.4 mi
Richland CountyMT · 49.7 mi

Earthquakes around the epicentre

3 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.

No earlier earthquake of magnitude 5 or more within 50 miles in the catalogue since 1900.

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