M5.7 earthquake 13 km SSW of Mammoth, Wyoming

A magnitude 5.7 earthquake struck 13 km SSW of Mammoth, Wyoming on Tue, Aug 18, 1959, 4:03 AM GMT-7 (11:03 UTC), 15 km (9 mi) below the surface.

A larger quake followed: M6.3 22 km SW of Mammoth, Wyoming. This one was a foreshock.

Map

Where this earthquake was located, with the others nearby. Select one for its page.

Different scales measure different things and differ by a few tenths. The USGS marks one as preferred, and it is the one this page uses.

Mag.	Scale	Computed by	Notes
5.67	Mw, moment	ISC-GEM global catalog	Preferred · Final · ±0.2
5.6	Uk	USGS historic United States catalog	Final

The USGS’s account of the effects of this earthquake.

Maximum observed Modified Mercalli Intensity (MMI) I

From the USGS event page for iscgem882677. U.S. Geological Survey text and figures are in the public domain.

The USGS ShakeMap: shaking estimated from seismic stations and the quake’s size, on the Modified Mercalli intensity scale.

No one has reported feeling this quake to the USGS.

Reviewed by a seismologist.

Distance and direction from each place to the epicenter, with its forecast.

Within 100 km, magnitude 2.7 and up: 7 in the 60 days after this one and 3 in the 30 days before it.

From the USGS Earthquake Hazards Program and its partner networks, event iscgem882677 (also filed as ushis2399). Read Sun, Oct 4, 2026, 3:17 PM UTC.