Mini quake shakes things up in Alexandria area
The rumbling started at 2:20 a.m. Friday.
"At first, we thought something had blown up, like a gas tank," Betty and Jack Yelle of Evansville wrote in an e-mail to the Alexandria Echo Press .
A 2.5 magnitude earthquake shook the Alexandria area, according to the U.S. Geological Survey. No damage or injuries were reported.
The Yelles reported hearing a loud boom and their home rattled, shaking a glass display cabinet filled with ceramic figurines.
Mike and Cyndi Nelson and their cat, Dave, were awakened from deep sleep inside their Alexandria home.
"It was a house-shaking rumble, sounding much like the winter lake ice cracking on a frigid day, but a hundred times more intense," Mike said.
Lisa Sanchez, who lives three miles north of Brandon, thought it felt like a tree hitting the house, or a car.
"After looking around, no downed trees, no intruders; I went back to bed. I knew I wasn't dreaming, because the dogs noticed something, too," she said.
The epicenter of the quake was reported to be located between Lake Mina and the airport near Alexandria.
The earth ruptured at a depth of five kilometers, according to USGS.
"These type of weak events happen in Minnesota from time to time," said Val Chandler, a geophysicist from the Minnesota Geologic Survey at the University of Minnesota.
Chandler said they estimate 19 earthquakes occurred in Minnesota since 1860 that were strong enough to be felt by people, with many happening in central and west-central Minnesota.
The last earthquake in the Alexandria area happened in 1950, according to Chandler.
Chandler said they think these earthquakes are caused by recent stresses acting on ancient faults in the earth's crust, producing minor re-activation.
"There is a large and ancient fault about 15 miles south of Alexandria that is known as the Great Lakes Tectonic Zone, and some geologists have speculated that it may be related to some of the earthquakes that have occurred in west-central Minnesota," Chandler said. "However, no one really knows for sure.
"Earthquakes of this sort are usually not associated with detectable aftershocks. So, I suspect that you have seen the last of any seismic activity in the Alexandria area for quite some time to come."
The Douglas County Sheriff's dispatch reported receiving 40 to 50 calls related to the quake.
"You just don't hear about earthquakes in central Minnesota," said Sergeant Brad Brejcha of the Douglas County Sheriff's Office at a press conference Friday. "It's the talk of the coffee shop this morning."
Facebook and Twitter came alive with posts like Michelle Schmidt's on the Echo Press Facebook page: "Amazing, scary and I couldn't sleep a wink after."
Most reports indicated the episode experienced by residents in the area lasted about 10 or 15 seconds.