M4.0 earthquake 84 km W of Hooper, Utah

A magnitude 4.0 earthquake struck 84 km W of Hooper, Utah on Thu, Sep 24, 1987, 10:09 PM MDT (04:09 UTC), 8 km (5 mi) below the surface.

A larger quake followed: M4.7 86 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
3.99	ML, local (Richter)	University of Utah Seismograph Stations	Preferred · Final · 2 stations
4.1	ML, local (Richter)	USGS National Earthquake Information Center	Reviewed

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

Felt in the Salt Lake City area.

From the USGS event page for uu50033590. 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: 122 in the 60 days after this one and 3 in the 30 days before it.

The first 60 of 122.

From the USGS Earthquake Hazards Program and its partner networks, event uu50033590 (also filed as usp00038pt). Read Thu, Oct 1, 2026, 11:41 AM UTC.