© Unknown
Mickey Hart lives five miles south of McCall just off Hwy. 55. The 50-year-old resident says she's only experienced one earthquake here, and it was in the summer of 2001. The second earthquake came early Thursday morning around 4:30 a.m. Hart says that's when her beloved border collie, Mr. Mac, detected the tremor before it hit.
"It was four in the morning, and the house shook," Hart said. "It woke up my husband and scared the crap out of my dog." However, for some folks here in Idaho, those reports just don't seem to make sense. U.S. Geological Survey Technical Information Specialist Tim Merrick said his agency's seismographs haven't shown any recent earthquake activity in Idaho. "If there was anything, it would almost certainly show up," Merrick said. "Our seismology network across the United States is very sensitive."
Scott VanHoff, USGS Geospatial Mapping Coordinator, agrees. "Idaho looks amazingly quiet, and I don't see anything," VanHoff said, adding that the only earthquake he'd seen recorded was yesterday.
USGS records show that event was a magnitude 2.2 earthquake recorded around 9:30 p.m., northwest of Weiser, Idaho. However, other folks in Valley County area maintain they positively did feel an earthquake early Thursday morning.
Captain Brandon Swain with the McCall Fire Dept. says he heard reports of the mystery earthquake from his brother Clint Swain, who lives near Lake Fork. "My brother was awake at about 4:30 or 5 a.m., and the earthquake woke up his wife," Swain said.
A possible answer
Research geophysicist Joan Gomberg works for the USGS at the University of Washington in Seattle. Gomberg says her seismic records do, in fact, show "something that could be small earthquake," recorded at 4:42 MDT in the McCall area.
However, Gomberg went on to say that most earthquakes strong enough to be felt by people easily show up on USGS seismographs throughout the United States.
As to why some experts can't readily see this one, Gomberg offered an interesting explanation.
"This area is at the edged of the Pacific Northwest Seismic Network and where the monitoring network begins to get sparser, so small earthquakes are more likely to be missed," Gomberg said.
Gomberg also reminds folks that sometimes a sonic boom from a nearby jet can feel like earthquake, along with large mining equipment, and road work.
However, Mickey Hart says she doesn't need a seismograph to tell her what she experienced was an earthquake. Instead, Hart says she trusts her border collie.
"Mr. Mac new right away. It really shook him up," Hart said.
I hypothesize that the magma chamber under Yellowstone is flowing westward due to an axis tilt.