The November 28, 1935 earthquake
M5.0near Helena, Montana
A magnitude 5.0 earthquake, centred in Lewis and Clark County. The 23rd strongest in Montana’s record since 1900, and the strongest within 50 miles since a magnitude 5.9 on October 31, 1935.
The earthquake
- Magnitude
- 5.0
- local magnitude (ml)
- Depth
- —
- Not recorded
- Local time
- Thursday, November 28, 1935
- 07:41 MST; 14:41 UTC
- In Montana’s record
- 23rd
- strongest of 1,459 since 1900
USGS ANSS Comprehensive Earthquake Catalog, event ushis1122 (“2 km ENE of Helena, 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
- Lewis and Clark CountyMT · inside
- Jefferson CountyMT · 2.6 mi
- Broadwater CountyMT · 10.3 mi
- Powell CountyMT · 13.9 mi
- Meagher CountyMT · 23.4 mi
- Cascade CountyMT · 23.8 mi
- Deer Lodge CountyMT · 35.2 mi
- Silver Bow CountyMT · 37.5 mi
- Gallatin CountyMT · 42.2 mi
Cities, largest first
- HelenaMT · 0.9 mi
Earthquakes around the epicentre
142 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
- June 27, 1925M6.6
- June 27, 1925M6.4
- October 18, 1935M6.1
- October 31, 1935M5.9
- October 12, 1935M5.9
- June 27, 1925M5.5
- June 27, 1925M5.5
- July 10, 1925M5.5
- April 19, 1910M5.4
USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.