A 6.5 magnitude earthquake hit southern Idaho around 5:52 p.m. Tuesday, March 31, according to the U.S. Geological Survey.
The quake, which lasted for 23.5 seconds, hit 19 miles northwest of Stanley — or about 78 miles northeast of Boise, according to USGS. It was felt throughout Idaho and in seven surrounding states, according to USGS’ Community Internet Intensity Map.
A 4.6 earthquake aftershock followed at 6:27 p.m. Local and state police did not report any damage or injuries Tuesday evening.
The strength of the earthquake was at the high end of the range for the area and follows a pattern of big quakes every two decades or so, Lee Liberty, a geophysics professor at Boise State University, told the Idaho Press.
“What I think it is is the Sawtooth Fault north of Stanley,” he said. “…There could be aftershocks in the coming hours, weeks, or we could experience aftershocks that could last for months.”
If you did feel a lot of shaking in downtown Boise, that’s no cause for alarm, Liberty said. Downtown Boise sits on sediments that amplify the shaking, but the movement shouldn’t cause too much damage in the area, he said, because the event was too far away and not big enough to cause any real issues.
“The problem will be in the mountains, where there was heavy rain and snow earlier today, so the chances of mudslides and avalanches are pretty real,” he said.
But Tuesday should be a “bit of a novelty,” something to remember, the professor of 25 years said.
The largest earthquake in Idaho history was the 6.9 magnitude Borah Peak earthquake in 1983, the Bozeman Daily Chronicle reports.
Marcus Smith, an emergency room health unit coordinator at St. Luke’s Wood River Medical Center, said the hospital, about 65 miles south of the epicenter, shook but the quake didn’t interfere with the treatment of any patients. The hospital in Blaine County is on the front line of Idaho’s coronavirus outbreak, in a region with the highest per-capita rates of known COVID-19 cases in the nation outside of New York City and surrounding counties.
“It felt like a wave going through the ground, so I knew right away what it was. It just felt like waves going through the ground,” he said.
The earthquake is added stress during an already stressful time for the region, but Smith said everything seemed fine, for now. “Until the next one, I guess,” Smith said. “I mean, that’s what we do. We’re all good.”
Brett Woolley, a restaurant owner in Stanley, said he heard earthquake coming before he felt it.
“I heard the roar, and at first it sounded like the wind but then the roar was tremendous,” Woolley said about 10 minutes after the earthquake. “The whole house was rattling, and I started to panic. I’m sitting here perfectly still and the water next to me is still vibrating.”
The USGS also recorded two small earthquakes near West Yellowstone on Tuesday, according to the Chronicle. The tremors had magnitudes of less than 3.
REPORTS IN IDAHO
Nampa and Boise police departments had received no reports of injuries in the quake’s immediate aftermath, according to department posts to Twitter.
”Yes, Nampa, we felt what appears to be an earthquake too,” Nampa Police tweeted at 6:08 p.m. “So far we do not have any reported injuries in the City of Nampa. If you don’t have an emergency — Please DO NOT CALL 911. Leave the emergency lines open for emergency calls.”
A few minutes later the Boise Police Department tweeted, “Yep we felt it too. No reports of damage at this time. Stay safe out there Boise. Call us if you need us.”
Idaho State Police said they received numerous calls from citizens about the earthquake, according to the Idaho State Journal. It wasn’t immediately known if there were any injuries or damage to property.
In East Idaho, residents reported feeling the quake in Rexburg, Pocatello and Burley. Idaho State Police said they’ve received reports that the quake was also felt in Utah. In Gem County (the Emmett area), reports of some rocks dislodged along Highways 16 and 52 appeared to be minor, and no road blockage was immediately reported, Emmett Messenger Index reports.
Anyone who felt the earthquake can fill out a “Felt Report” through the U.S. Geological Survey to help in efforts to gather details about the event. Click here to complete the form.
Idaho Press reporter Thomas Plank contributed.