M2.7 earthquake 63 km SSE of Mammoth, Wyoming

A magnitude 2.7 earthquake struck 63 km SSE of Mammoth, Wyoming on Fri, Jul 16, 2021, 10:01 AM MDT (16:01 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M3.6 63 km SSE 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
2.73	ML, local (Richter)	University of Utah Seismograph Stations	Preferred · Final · ±0.238 · 6 stations
2.3	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed · ±0.071 · 26 stations

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 1.5 and up: at least 200 in the 60 days after this one and 159 in the 30 days before it.

The first 60 of at least 200.

From the USGS Earthquake Hazards Program and its partner networks, event uu60446372 (also filed as us7000emk3). Read Sun, Oct 4, 2026, 11:44 PM UTC.