Aftershocks and earthquakes rumble near Lima

Posted at 12:59 PM, Apr 10, 2019
and last updated 2019-04-10 14:59:55-04

The United States Geological Survey continues to record earthquakes near Lima after two rumbled in the area on Tuesday.

The USGS reported a 4.4 magnitude earthquake hit at 12:08 p.m. about 3.7 miles northeast of Lima Tuesday closely followed by a 3.5 magnitude earthquake at 12:11 p.m. about seven miles northeast of the town.

The USGS then recorded three more earthquakes, or aftershocks, in the area Tuesday night and Wednesday morning all about six miles northeast of Lima.

The first 2.6 magnitude quake was 6.5 miles in depth while the second 3.4 magnitude earthquake was 6.6 miles beneath the surface. The last 2.6 earthquake was at a depth of 6.9 miles.

Geologist Michael Stickney told MTN News there were reports of Butte residents feeling Tuesday’s earthquakes while some people in Lima described them as a bomb or an explosion.

One of Tuesday’s earthquakes occurred along a fairly active fault called the Centennial Tectonic Belt, but it hasn’t experienced a major quake in decades.

“The really significant earthquake that occurred in this zone was the 1983 Borah Peak Idaho earthquake, which had a magnitude of 6.9. It resulted in two fatalities in Challis and caused significant damage,” Stickney said.

The strongest earthquake to hit Montana in more than a decade happened near Lincoln in July 2017.

BACKGROUND: According to the USGS, Montana is one of the most seismically-active states in the country, although the vast majority of recorded earthquakes are very small, causing no damage and rarely noticed by people. 

Montana is located within the Intermountain Seismic Belt, an active earthquake region stretching along the Rocky Mountains. It is the fourth-most seismically active state, although the vast majority of earthquakes in Montana are too small to be felt.

But there are exceptions. About 90 years ago, a large earthquake hit southwest Montana. The quake damaged a school house in Three Forks, twisted railroad tracks along the Missouri River, and damaged a jail in White Sulphur Springs. 

Ten years after that another big quake hit Helena, killing two people and causing millions of dollars in damage. It damaged churches, collapsed walls right out of homes, and hit commercial and government buildings as well.