Persistent Aftershocks Shake Aleutian Chain

Thursday, September 05 2013


6.2 aftershock south of Atka and Adak / Credit: Alaska Earthquake Information Center

Hundreds of aftershocks are rattling the Aleutian Chain following a 7.0 earthquake near Adak on Friday. As KUCB’s Ben Matheson reports, residents are ready for life to go back to normal -- but it could be months before the quakes subside.


The largest aftershock so far was bigger than most earthquakes in the chain. On Tuesday night, a 6.2 quake rumbled past Atka and Adak. Nothing was damaged, and it didn’t trigger a tsunami -- and the same goes for the other earthquakes that have hit the chain in the past week. But they’re starting to take their toll.

Adak city manager Layton Lockett says his office is constantly swaying.

Lockett: "It feels like you’re going around in  a circle, that kind of roundish movement."

Adak residents have to dart in and out of their homes to evacuate during aftershocks. They’re brief, but constant.

Lockett: "It’s kind of got us thinking, ‘Wow, is there a sequence to this, or is something really going on?’ As it’s prolonged, the worry is, ‘Is this even normal for a geological event?’  Because it doesn't feel like it."

According to Natasha Ruppert, it is. Ruppert is a seismologist with the Alaska Earthquake Information Center.  

Ruppert: "This is expected for a magnitude 7 [earthquake] to produce hundreds or even thousands of aftershocks."

Many of these aftershocks register at magnitude 5 or 6.  That’s serious shaking, and if a big quake hits at the right spot, it could trigger a tsunami.  

Bill Dushkin is a village public safety officer in Atka. He’s felt at least five aftershocks since Friday.  

Dushkin: "Everybody is kind of getting used to them now, kind of desensitized to them, a little."

Still, Dushkin says Atka’s taking precautions. He stays in contact with the Alaska Tsunami Warning Center. And most residents are keeping their VHF radios turned up in case there’s a call to evacuate.

That heightened alert level will stay in place for the time being. Ruppert, the seismologist, says it could be at least a few weeks before things calm down.

Ruppert: "The frequency of the aftershocks will continue to go down, but it won’t be back down to background levels for a couple of months later."

And that’s true for communities beyond Atka or Adak. The Aleutian Chain is on a big fault, which might explain why two earthquakes hit near Unalaska early Wednesday.

They weren’t aftershocks of the big 7.0 earthquake, but Ruppert says they may be a part of the larger seismic pattern that’s rippling through the western Aleutians. And that means, the entire chain could be in for a bumpy season.



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