Scientists log record number of Alaska earthquakes in 2017 using growing network of seismic stations

Alaska tallied a record number of earthquakes in 2017, thanks to an army of high-quality seismometers that have been installed during the last three summers in the state.

The EarthScope Transportable Array is a network of seismic stations across the contiguous U.S. and Alaska funded by the National Science Foundation, which aims to collect new data about the North American continent.

The project has "essentially blanketed Alaska with these high-quality seismometers," said Lea Gardine, outreach specialist with the Alaska Earthquake Center.

"We have stations where we haven't before, primarily in northern and western Alaska," Gardine said. "Now we've got exceptional coverage."

In 2014, the project began installing seismic stations in Alaska. This last field season, the vast majority of the northern and western stations were put in, Gardine said.

A total of 280 stations cover Alaska and Western Canada, according to the project's website. Each one is roughly 50 miles apart.

The equipment appears to be working, as evidenced by the fact that Alaska logged a record-high number of earthquakes in 2017 — 40,898 by Thursday afternoon, with more racking up every hour, Gardine said.

"We locate anywhere from probably 80 to 100 (earthquakes) per day," Gardine said. "We can easily anticipate a thousand more this year."

This year, Alaska didn't have any large earthquakes, which will trigger hundreds — sometimes thousands — of aftershocks. The magnitude-7.9 Denali Fault earthquake in 2002 had "tens of thousands" of aftershocks, Gardine said.

That leads Gardine to believe that it's the new seismic equipment that is responsible for the increase.

The previous record year was 2014, when 40,600 quakes were recorded, Gardine said.

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Earthscope is a partnership between more than 100 universities, the National Science Foundation, U.S. Geological Survey, NASA, the Energy Department, regional seismic networks and state geological surveys, according to the project's website.

But the boost in earthquake monitoring is temporary; the seismic monitors are scheduled to be removed in 2019 unless funding can be secured, Gardine said.

About 20 percent of all of Alaska's earthquakes are in the Aleutians. Many are also centered in Southcentral Alaska, Gardine said.