Seismologist: Quake’s Depth Helped Minimize Damage

A magnitude 6.2 earthquake hit Southcentral Alaska at 9:51 this morning. Michael West directs the Alaska Earthquake Center in Fairbanks. He says the epicenter was about 60 miles Northwest of Anchorage and 60 miles underground.

Listen now:

“That’s pretty deep for Alaska and the reason for that is that’s where the Pacific plate dives under North America in a process we call subduction but because of that we are well accustomed to seeing a line of progressively deeper earthquakes as we move north from the coast. So in that sense, this earthquake is not a surprise at all.”

No major damage has been reported.

quake photo 1

But the shaking caught the attention of residents across a large swath of the state, from Fairbanks down to Homer. In Anchorage, residents posted pictures on Facebook and Twitter of messy aisles in Fred Meyer, with shampoo bottles scattered across the floor, and tiles missing from ceilings in midtown buildings.

West says it’s difficult to gauge the length of the earthquake. The Earthquake Center took reports from residents saying it lasted anywhere from several seconds up to a full minute. He says the deep basin of Cook Inlet may explain the difference:

“The analogy we use is it shakes like a bowl of Jello so certainly our hypothesis right now is that this earthquake set the basin shaking and that because of that people close to Cook Inlet may have felt this for a much much longer time than other places. And that’s kind of exciting because we see this in data sometimes, but we don’t often have on site reports from people confirming that kind of observation.

West says events like this one are a reminder of what earthquakes are capable of in Alaska. He says a strong earthquake like this one that was more shallow and centered closer to a city would be capable of causing widespread damage and even death. A 6.3 magnitude earthquake in Christchurch, New Zealand in 2011 killed 185 people. West says he worries Alaskans have been lulled into thinking that big earthquakes are no big deal.

“So it’s quite easy to think, oh there’s another magnitude six or seven that didn’t do anything and that is not in any way a predictor that magnitude six or seven earthquakes don’t hurt us, it just means we’ve been lucky yet again.”

West is in Washington, D.C., right now to make the case for long term funding for an expanded seismic network across Alaska to monitor earthquakes.

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Annie Feidt is the Editor and Producer of Alaska News Nightly, and is also a frequent contributor to the show. Her reporting has taken her searching for polar bears on the Chukchi Sea ice, out to remote checkpoints on the Iditarod Trail, and up on the Eklutna Glacier with scientists studying its retreat. Her stories have been heard nationally on NPR and Marketplace. Annie’s career in radio journalism began in 1998 at Minnesota Public Radio, where she produced the regional edition of All Things Considered. She moved to Anchorage in 2004 with her husband, intending to stay in the 49thstate just a few years. She has no plans to leave anytime soon. afeidt (at) alaskapublic (dot) org  |  907.550.8443 | About Annie