Alaska sees world’s largest earthquake for 2nd consecutive year, new report says

ANCHORAGE, Alaska (KTUU) - Scientists have released the latest data detailing Alaska’s 2021 earthquakes.

For the second year in a row, the state has taken the title for having the year’s largest quake in the world.

In 2020, there was a 7.8 earthquake off the coast of Perryville on the Aleutian Chain. And 2021 had an 8.2 quake nearby.

That 8.2 quake was also the largest in the United States in 50 years, according to the report.

“The last earthquake comparable to this size was in 1965,” Alaska Earthquake Center Seismologist Lea Gardine, who worked on the report, said.

“As far as having the largest earthquake in the world, that’s not surprising to us. We have a very, very active region of seismicity,” Gardine said.

There is no reason to believe these two quakes mean anything significant, she said. The Aleutian Islands always have the potential for large earthquakes at any given time. Gardine said an earthquake in 1938 happened in a very similar way to last year’s 8.2.

“We’ve got a lot of area that we cover, a lot of potential for earthquakes and just a lot of things all happening. So, it’s not surprising that we would have large earthquakes. The fact that it was two years in a row is probably just coincidental,” she said.

Gardine explained that 2021′s magnitude 8.2 quake didn’t have as many aftershocks as seismologists were expecting. This can vary based on things like they type of earthquake, the type of fault and its location, she said.

The report also mentioned the aftershocks from the 7.1 earthquake in 2018 near Anchorage.

“Three years later, we’re still getting Anchorage aftershocks,” Gardine said. “It’s still producing earthquakes that people are feeling, including magnitude 5s, which could be the new normal for this region.”

“We’re not entirely sure how all that’s going to settle out, but because that area is so active and we’ve got to look at all the various things that are going on, it makes it harder to tell whether that that area is fully settled down yet or if we could have another year or two of aftershocks,” she said.

Gardine said it’s hard to pin down how long the aftershocks from that quake will continue, but her best estimate is into 2023 or 2024.

“There’ll be an aftershock, and a magnitude 5 aftershock will produce more aftershocks,” she said.

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