M3.3 earthquake 18 km SW of Thatcher, Utah

A magnitude 3.3 earthquake struck 18 km SW of Thatcher, Utah on Fri, Oct 2, 1987, 8:35 AM MDT (14:35 UTC), 7 km (4 mi) below the surface.

A larger quake followed: M4.6 85 km E of Montello, Nevada. 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
3.33	ML, local (Richter)	University of Utah Seismograph Stations	Preferred · Final · 2 stations
3.5	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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

Felt (III) at Garland. Also felt at Golden Spike National Historic Site.

From the USGS event page for uu50033830. U.S. Geological Survey text and figures are in the public domain.

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: 101 in the 60 days after this one and 42 in the 30 days before it.

The first 60 of 101.

From the USGS Earthquake Hazards Program and its partner networks, event uu50033830 (also filed as usp00038xe). Read Thu, Oct 1, 2026, 9:45 AM UTC.