Valley shimmies at 4.9

MAT-SU — That rumbling you felt a little before 1:30 p.m. Monday wasn’t a large truck barreling past. It was one of dozens of earthquakes recorded in Alaska on what researchers call a typical day in the most earthquake-prone state in the union.

“It’s pretty standard, I would say,” said Natasha Ruppert of the 4.92-magnitude quake that rolled much of Southcentral at 1:24 p.m. Monday.

Ruppert is a seismologist for the Alaska Earthquake Information Center based at the University of Alaska Fairbanks. Of the quakes the center measures daily, most go unnoticed, she said.

“There are lots of earthquakes each day in the Cook Inlet area, up to 20 a day we can see,” she said. “I expect there will be a few aftershocks, because a 4.9 will produce aftershocks for up to a week.”

Monday’s shake originated about 40 miles southwest of Wasilla and was felt as far north as Talkeetna, Ruppert said, classifying the 4.9 measurement as “moderate.”

“Wasilla is pretty close to the epicenter, so I would expect you could feel it,” she said. “People felt it all the way in Talkeetna. It was pretty mild there, but still noticeable.”

Feeling the occasional ground shimmy shouldn’t take most Valley residents by surprise, Ruppert said.

“If you consider all the United States, Alaska is the most active in the U.S., with anywhere from 50 to 100 earthquakes a day,” she said. “Most are small earthquakes nobody feels, but sometimes you get one like today, a 4.9 in a central part of the state that can be felt by thousands.”

Contact Greg Johnson at greg.johnson@frontiersman.com or 352-2269.