Science

Recent Southeast Alaska earthquake surprised some geologists

After a 7.7-magnitude earthquake rolled through Southeast Alaska on Jan. 4 just before midnight, resulting in a tsunami warning that stretched to Cape Suckling, 75 miles southeast of Cordova, many Cordova residents were glued to the NOAA West Coast and Alaska Tsunami Warning Center's website, watching updates as the event unfolded.

"Yeah, we've been a little busy," said Cindi Preller, tsunami program manager for NOAA. "Our little planet just can't quite settle down.

Preller says the quake was strongly felt throughout the southeast region, with Craig being the nearest community to the epicenter. Juneau residents reported rocking and rolling, broken dishes. "People were surprised. It rolled for quite a bit."

Preller said the event shocked some observers. "With the exception of a weak event in 2004, the last time we had any activity in the Queen Charlotte fault system was 1972. This event was surprising. We've really only had two large earthquakes on that fault. This one landed between those two."

A 1949 earthquake on the same fault registered at 8.1 magnitude. In 1972 another major event registered at 7.6 magnitude.

Preller says staff at the center were relieved no one was hurt, but cautioned residents not to be lulled by the what turned out to be a minor tsunami.

"We were really lucky that nobody was injured and a major tsunami was not produced," said Preller who in addition to staffing the center, travels to communities to help them understand and prepare for earthquakes and tsunamis. "We want people to take this as a serious reminder to be ready."

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Preller points to the Lituya Bay event of 1958, which triggered a landslide that produced the largest tsunami ever recorded.

"The quake was originally thought to be a 7.7, but it was later determined to be a 8.2. The landslide that it triggered produced a tsunami that was recorded splashing at 1,720 feet," said Preller. "In an event like that, there isn't time to figure out what to do. People need to take this notice seriously.

"We warn people to the highest potential threat that we see. These events can trigger many things -- landslide, a sub-marine slide. Just because we don't have a report of a landslide, does not mean that it did not happen."

Preller reminds all Alaskans to have a household emergency plan that all family members learn, including evacuation plans and a tsunami kit ready that will provide essential food and water for seven days.

This article originally appeared in The Cordova Times, and is republished here with permission. You can reach Jennifer Gibbins with comments and suggestions at editor(at)thecordovatimes.com

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