A new report released by the Alaska Earthquake Center shows a quiet year for earthquakes in 2022. Last year alone, there were over 47,000 earthquakes in Alaska and surrounding regions. The number, while large, is actually a slight decrease in seismic activity compared to recent years, when activity has been high.
“The 2022 year was kind of a quiet year for us,” said Natalia Ruppert, a seismologist with the Alaska Earthquake Center at the University of Alaska Fairbanks’ Geophysical Institute. “But this is how the earthquake cycle works.”
She said there are years that experience higher activity, like 2018, which was notable for its large earthquake near Anchorage, and years of lower activity. But she said the past five years have seen an increased spike in recorded seismic activity.
There are two reasons for this, according to Ruppert. The first is a higher number of seismic stations in Alaska than in previous years.
During 2019 and 2020, a program funded by the National Science Foundation installed about 200 seismic monitoring sites in Alaska and Western Canada for the purpose of tracking earthquake activity. As a result, much more data is being tracked, and researchers are seeing a broader scope of seismic activity in the state. The sites were going to be removed by 2021, but the Alaska Earthquake Center was able to acquire most of these sites to continue its research.
The second reason for increased seismic activity is aftershocks. Alaska has seen a few big-ticket earthquakes in the past five years including an earthquake in 2021 that had a magnitude of 8.2.
Ruppert said that large-magnitude earthquakes generate more aftershocks, which can carry on for years after the initial earthquake.
“We always underestimate the duration of aftershock sequences. The Anchorage earthquake was projected to have aftershock sequences on the order of two and a half to three years, and now we are kind of four-plus years into the sequence,” she said.
Because of the unpredictable nature of the earthquakes — even in quiet years like last year — Ruppert still emphasized the need for the public to pay attention to earthquake activity.
“People should still be prepared because in Alaska we have very high seismicity rates, high seismic hazards, and it’s good for people just to be ready for a significant earthquake at any time,” she said.
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