Yes, that was an earthquake near Ketchikan on Sunday night. Here’s why it didn’t show up online

A map showing Sunday night’s M4.1 earthquake (orange circle) and nearby seismic stations (triangles and gray circles). (Screenshot of Alaska Earthquake Center website)

Ketchikan Mayor Dave Kiffer was about ready to call it a night on Sunday when he felt something familiar.

“I was laying in bed reading, and I felt the entire house just sort of shimmy a little bit, and I went, ‘Oh, I know what that is! I’ve felt that before,’” Kiffer recalled on Monday.

So he did what anyone in the 49th State does right after a little shake: checked the Alaska Earthquake Center’s website.

“Zippo, nada, nothing,” he said.

A little while later, there were a few earthquakes listed in other parts of the state, but still nothing near Ketchikan.

So Kiffer decided to check in with some seismologists to the south.

“What happened last night was a moderate sized earthquake, magnitude 4.2,” said Honn Kao, a research scientist at the Geological Survey of Canada. His agency pinpointed the epicenter about 50 miles southeast of Ketchikan — 10 kilometers beneath the Misty Fjords, just barely on the U.S. side of the border.

“Its location is right around the border between Alaska panhandle and BC,” he said.

A magnitude 4.2 isn’t a huge earthquake by any stretch. But Kiffer says he was a little peeved when he woke up the next morning and state seismologists still hadn’t noted the earthquake.

“Seriously, what are we, chopped liver?” Kiffer said with a laugh.

Between 9:57 p.m. Sunday, when the earthquake struck near Ketchikan, and 6 a.m. the next morning, the state’s automated seismic stations recorded 11 earthquakes all over the state ranging in magnitude from 1.1 to 3.5. But there was still nothing listed near Ketchikan on the websites of the U.S. Geological Survey or the Alaska Earthquake Center.

“Usually the state does a real good job — I never have any complaints for them,” he said. “It’s kind of puzzling. It’s like, maybe they thought we were part of Canada.”

It wasn’t until Monday afternoon that Alaska authorities acknowledged the earthquake, estimating the magnitude at 4.1. Alaska Earthquake Center Senior Scientist Natalia Ruppert chalks up the miss to inadequate seismic sensor coverage.

“Unfortunately, our network in that region is not as comprehensive,” she said. “So at the moment, last night, we actually missed detecting that earthquake, but this morning, we actually went back and looked at our data and reanalyzed the data, and we were able to report on that earthquake as well.”

And while she says the Alaska Earthquake Center does its best to include as much data from Canadian earthquake sensors as possible, she says Alaska earthquake monitors weren’t receiving data from nearby Canadian stations on Sunday night.

“We try to exchange data, but the networks change, and sometimes they update things and those updates don’t propagate all the way into our system,” she said.

Honn Kao, from the Canadian earthquake agency, says stations in Prince Rupert and Haida Gwaii picked up the shaking. But he says it’s unlikely that a larger earthquake would go unnoticed.

“If we have a relatively big event, then all the stations, far and near, can detect a signal and therefore, it can be located by any agencies,” he said. “But for events that are smaller than magnitude 5, usually only local stations can detect the event better.”

Kiffer, the Ketchikan mayor, says he’s not especially concerned that domestic agencies missed the quake.

“It’s just humorous to me, more than anything else,” he said. “I mean, I we don’t get these very often. It’s nice to show up statewide and be counted.”

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