M6.3 earthquake 22 km SW of Mammoth, Wyoming
A magnitude 6.3 earthquake struck 22 km SW of Mammoth, Wyoming on Tue, Aug 18, 1959, 8:26 AM GMT-7 (15:26 UTC), 10 km (6 mi) below the surface.
Map
Where this earthquake was located, with the others nearby. Select one for its page.
The earthquake
- Magnitude
- 6.3 (mw), strong
- Local time
- UTC
- 1959-08-18 15:26:10 UTC
- Depth
- 10.0 km (6.2 mi), shallow
- Epicenter
- 44.812° N, 110.864° W
- Region
- Montana
- Strongest shaking
- VIII, severe shaking
- Tsunami flag
- No
- Status
- Reviewed by a seismologist
Shaking
The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.
- Strongest estimated
- VIII, severe shaking
- Peak ground acceleration
- 47.4% of gravity
- Peak ground velocity
- 3.8 cm/s
- Map
- Automatic
Did you feel it?
No one has reported feeling this quake to the USGS.
How well it is located
Reviewed by a seismologist.
- Magnitude uncertainty
- ±0.20
- Depth from
- From location
Nearest places
Distance and direction from each place to the epicenter, with its forecast.
Nearby
Within 100 km, magnitude 2.5 and up: 6 in the 60 days after this one and 2 in the 30 days before it.
After
- 6.021 km E of West Yellowstone, Montana · 24506 days ago · 5 km deep · 18 km away
- 5.031 km W of Hebgen Lake Estates, Montana · 24506 days ago · 5 km deep · 57 km away
- 5.015 km NE of West Yellowstone, Montana · 24506 days ago · 5 km deep · 10 km away
- 4.732 km W of Hebgen Lake Estates, Montana · 24506 days ago · 5 km deep · 59 km away
- 5.039 km W of Hebgen Lake Estates, Montana · 24505 days ago · 5 km deep · 65 km away
- 4.46 km NNW of West Yellowstone, Montana · 24481 days ago · 5 km deep · 23 km away
Before
Earthquakes todayMontana earthquakesLive radar here
Sources
From the USGS Earthquake Hazards Program and its partner networks, event iscgem882678 (also filed as ushis2400). Read Tue, Sep 22, 2026, 11:00 AM UTC.