BOISE, Idaho — The day after a magnitude 6.5 earthquake rattled Idaho, authorities near the epicenter say there have been no reports of significant damage or injuries.
The Idaho Department of Lands (IDL) Division of Minerals, Public Trust and Oil and Gas is working with operators for initial checks on oil and gas wells in Payette County. So far, no initial problems have been found. There will be further inspections of all facilities and wells through the end of the week.
Initial checks on surface mines also have not indicated any problems. IDL field staff will continue to work with mine operators, as well as state and federal agencies in evaluating the situation. The main focus will be on facilities and water handling operations to ensure that earthen dams and holding ponds have not been damaged by the earthquake.
Kathy Rodgers, a dispatcher with the Custer County Sheriff’s Office, said calls poured in following the earthquake just after 6 p.m. on Tuesday, but all appears to be well in central Idaho region. The county is sparsely populated with roughly 4,300 residents.
“It’s wonderful. We got a lot of calls, but no damage and no injuries,” Rodgers said Wednesday morning.
At least 47 aftershocks had been recorded by the U.S. Geological Survey by mid-morning, with the largest one measured at a magnitude 4.6.
More than 2 million live in the region that could feel the initial Idaho quake, according to the USGS. The temblor was centered 73 miles northeast of Meridian, near the rural mountain town of Stanley.
The USGS aftershock forecast predicts residents are likely to feel aftershocks for the next week or so, but the chance of one reaching magnitude 6 or higher is only estimated at about two percent.
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 nation’s highest per-capita rates of known COVID-19 cases outside of New York City and its 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 added stress during an already tense 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, the owner of Bridge Street Grill in Stanley, said he heard the 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 ten minutes after the earthquake. “The whole house was rattling, and I started to panic.”
Dr. Lucy Jones, a seismologist at Caltech and the founder of the Dr. Lucy Jones Center for Science and Seismology, said the Idaho region has an earthquake of about this size every thirty to forty years. The most recent one, a magnitude 7.0 earthquake near Borah Peak in 1983, killed two children in Challis and caused an estimated $12.5 million in property damage across Challis and Mackay.
That quake was along what scientists call a “normal fault,” with the quake causing vertical movement, she said. Tuesday’s quake appeared to be on an unmapped “strike-slip fault,” causing mostly horizontal movement along the fault line.
“This is one that wasn’t obvious enough to be mapped before now,” Jones said.
Unmapped faults of this size are rarer in highly-populated areas like California, she said, but in sparsely-populated and remote regions like central Idaho, they’re less likely to cause damage and less likely to be a focus of geologists and seismologists.