Rare 5.8 earthquake strikes western Montana, the area's strongest temblor in at least 20 years

 

A rare magnitude 5.8 earthquake has struck western Montana, plunging a town into darkness and powerful enough to knock down shelves and break glass, the U.S. Geological Survey said.
Western Montana hasn’t seen an earthquake greater than magnitude 5 in the past 20 years, said USGS geophysicist Robert Sanders.
“It’s not impossible, but it is a very rare event,” Sanders said.
The earthquake was felt as far away as Spokane, Wash., Boise, Idaho, and Calgary in Canada, Sanders said. More than 10,000 people reported feeling the earthquake, with people closest to the epicenter reporting shaking as strong as intensity level 8 — capable of causing significant damage.

There were no immediate reports of severe damage, however, although locals will get a better sense of greater damage after daylight breaks, Sanders said.

The earthquake struck at 12:30 a.m. Central Daylight Time Thursday in Montana, and was followed by at least six aftershocks in the magnitude 3 and 4 range over the next hour. The local sheriff’s office reported that the town of Lincoln, population 800, was without power. Lincoln is about three miles away from the epicenter.
A National Weather Service office in Montana said it had received a report of a gas leak in Helena, the state capital, and things falling off walls in Great Falls. Helena was estimated to have a shaking of intensity level 4, or light shaking that can awaken people and cause dishes and windows to rattle, causing some to feel as if a heavy truck struck a building.

A 76-year-old resident of Helena, which is about 34 miles away from the quake’s epicenter, told the Associated Press the earthquake was the strongest seismic activity that he had ever felt.

Ray Anderson told the AP his wife told him the temblor woke up the dogs.
Thursday’s Montana earthquake is unrelated to an ongoing earthquake swarm northwest of Yellowstone Lake, Sanders said. The swarm has been going on for a little over two months, with the largest a magnitude 4.5. But most have been very small, recording in magnitude of 0.5 or 0.6, which are typical in places like Yellowstone every few years, Sanders said.
Yellowstone is home to an active volcano; it last produced a lava flow about 70,000 years ago.

http://www.latimes.com/nation/nationnow/la-na-earthquake-montana-20170706-story.html