Utah’s Most Powerful Earthquake Really Tipped the Ritcher Scale

Utah is in a seismically active part of the United States despite not being on a boundary between tectonic plates. Still, the state has some active faults including the Wasatch fault. This fault most recently made headlines for the 2020 Salt Lake City Earthquake, a 5.7 M_w quake. That event was not the most powerful one to hit The Beehive State. Discover Utah’s most powerful earthquake and find out how strong it was, where it struck, and more!

What Was Utah’s Most Powerful Earthquake?

Utah’s most powerful earthquake was a 6.5-7.0 M_w quake that struck near Richfield on November 13, 1901. A fair amount of information surrounding the quake is uncertain. For example, the United States Geological Survey (USGS) did not record a specific magnitude for this quake.

However, the University of Utah lists the quake as a 6.5 M_w+ earthquake. A report prepared by Margaret G. Hopper in 1988 claimed a magnitude of 7.0 M_w along with a maximum intensity of IX (Violent) on the Modified Mercalli intensity scale.

Although scientists may disagree on the quake’s overall magnitude as well as its intensity, many accounts of the quake and its power exist. According to reports filed in the immediate aftermath of the earthquake, the event had a tremendous impact on the area.

People in a 50,000-square-mile area felt the earthquake. The main shock of the earthquake lasted anywhere from 1 to 3 minutes, though some areas experienced a shorter event. The quake tore up the landscape near Richfield, leaving ruptures measuring hundreds of feet long. Landslides struck throughout the region, but they seem to have been limited to remote areas.

Many buildings were damaged by the seismic event, though. Foundations and walls cracked, and chimneys collapsed. Dozens of aftershocks followed the main event.

What Caused the 1901 Richfield Earthquake?

Scientists at the USGS did not determine a depth or direct cause of the 1901 Richfield earthquake. However, seismic activity in the area is fairly common, and many of the strongest quakes in this area have happened in Sevier County.

Where Was the Earthquake’s Epicenter on a Map?

The earthquake’s epicenter was located at 38.77°N 112.08°W. That puts the epicenter near Richfield, Utah in Sevier County. The town is in the Sevier Valley, nestled between mountains. Today, the population in this town is only 8,000. Relatively few people were living in this area at the time of Utah’s most powerful earthquake.  The city is about 137 miles south of Salt Lake City in the southern-central part of the state.  

What Damage Did Utah’s Most Powerful Earthquake Do?

The earthquake, while widespread, did not do a great deal of damage to settlements. Some structural damage to walls and chimneys was reported in places like Richfield, Elsinore, and other nearby towns. However, over two dozen buildings in Beaver County, 45 miles southwest of Richfield, experienced damage from the earthquake.

According to Margaret Hopper’s report, the earthquake’s intensity was measured at IX (Violent). Landslides covered roads as far away as Salt Lake City. So, the earthquake caused some serious damage. Fortunately, it occurred in a somewhat remote area, so the impacts on people were somewhat small.

Did the Quake Cause Any Casualties?

Despite being Utah’s most powerful earthquake on record, this seismic event did not cause any casualties. At least, no casualties were recorded in any records about the event. No people were killed or seriously injured by the earthquake. Compared to some of the strongest earthquakes in the world, the one in Utah was fortunately not as potent.

A few factors kept the casualties to a minimum during the 1901 Richfield earthquake. They include:

• The quake happened in a place with a low population.
• The earthquake was only a 6.5 to 7 M_w event.
• The earthquake’s intensity, while high, was not as potent as it could have been.

For all these reasons, the earthquake did not kill any people in the area in which it struck. At least, no records of people dying as a result of the earthquake exist.

Aside from human casualties, we know very little of the quake’s impact on animals. Aside from animals experiencing restlessness and unusual behavior in the leadup to the earthquake, it is unknown if any perished in the event.

All in all, a fair amount of information about Utah’s most powerful earthquake is unknown. Currently, we only have estimates about the quake’s overall strength and impact. However, given that the second-strongest earthquake in the state was 6.3 M_w, even if the 6.5 M_w estimate is closer to the truth, it would still be considered the strongest one to hit the state.

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