A seismic station near the John River in the Brooks Range north of Bettles during a trip in which technicians serviced it on July 19.                                 <span class="neFMT neFMT_PhotoCredit">^</span>                                <span class="neFMT neFMT_PhotoCredit">Courtesy Photo </span>                                <span class="neFMT neFMT_PhotoCredit">| <strong>Max Enders</strong></span>

A seismic station near the John River in the Brooks Range north of Bettles during a trip in which technicians serviced it on July 19. ^ Courtesy Photo | Max Enders

Listening to the heartbeat of Alaska

280 seismic stations silently do their jobs.

Across Alaska and a sliver of western Canada, 280 seismic stations silently do their jobs. Hidden in dark holes drilled into rock in boreal forest, northern tundra and mountaintops, the instruments wait patiently for the next tremor.

The EarthScope Transportable Array of seismic monitors is now embedded across Alaska and Canada, adding 196 new stations to existing networks. The stations have spent the past year recording even the smallest earthquakes, sounding out an unprecedented level of detail about Alaska’s rumblings and transmitting that information in real-time.

EarthScope, its national office housed at the University of Alaska Fairbanks Geophysical Institute, is a National Science Foundation program focused on mapping the dynamic geological structure of North America. The Transportable Array is hundreds of seismic stations deployed in a grid; it has leapfrogged its way every two years across swaths of the continent for more than a decade. Now, it’s Alaska’s turn.

Technicians and engineers with EarthScope partner Incorporated Research Institutions for Seismology finished installing new stations and upgrading existing stations in fall 2017. The grid spacing is about 50 miles between stations, from Southeast Alaska to the North Slope.

Each station consists of a small borehole drilled into rock that houses a seismometer, which records vibrations in the ground. The boreholes are about nine feet deep; the surrounding rock shields the sensitive seismometer from surface noise.

The stations have proved durable in the harsh northern environment. Max Enders, station deployment coordinator at IRIS’s Alaska office, says bears are sometimes curious about this strange new thing in their environment.

“A little chewing by a bear can really damage a delicate seismic cable, even if it just bites the cable once or twice,” he said.

In addition to seismometers, some stations may host weather monitors, soil-temperature gauges and infrasound microphones sensitive to sounds generated by storms and volcanoes.

Before the arrival of the Transportable Array, the existing permanent seismic stations were huddled around Southcentral and Interior Alaska, the most active earthquake zones near Alaska’s largest population centers.

Alaska Earthquake Center scientists started using the real-time data from the new stations as soon as the first ones went live in 2014. This is the first year with the full array. It’s catching some intriguing results.

For the second year in a row, Alaska will break its record number of earthquakes detected. According to seismologist Natalia Ruppert, in 2017 they recorded 42,000 earthquakes. Alaska surpassed that with 46,500 earthquakes by early December 2018.

The November 30 magnitude 7.0 Anchorage earthquake and the aftershocks added more than 2,200 new earthquakes in just five days.

There are only two parts of the state where seismometers haven’t recorded earthquakes: around the Kuskokwim River delta and the northwestern North Slope.

“There are instruments in place there now, so we know that the absence of earthquakes is because they aren’t happening, not just due to lack of local monitoring,” said Ruppert.

The nearly 200 stations EarthScope installed are scheduled for removal starting in 2020, though there are discussions underway to keep some stations in place long term.

“For now, we are just collecting as much data as possible while the TA is in place,” said Ruppert. “It will take years for researchers and students to comb through the data to look for other interesting trends and discoveries.”


• Beth Grassi is a science writer for EarthScope. Since the late 1970s, the University of Alaska Fairbanks’ Geophysical Institute has provided this column free in cooperation with the UAF research community.


More in News

(Juneau Empire file photo)
Aurora forecast through the week of Nov. 17

These forecasts are courtesy of the University of Alaska Fairbanks’ Geophysical Institute… Continue reading

An aerial view of people standing near destroyed and damaged buildings in the aftermath of Hurricane Helene flooding on Oct. 8, 2024 in Bat Cave, North Carolina. (Mario Tama/Getty Images)
Members of U.S. Senate back disaster aid request amid increasing storm severity

WASHINGTON — The Biden administration’s request for nearly $100 billion in natural… Continue reading

Media members and other observers gather at the Alaska Division of Elections office on Wednesday evening as the results of all ballots, including ranked choice tabulations, were announced. (Mark Sabbatini / Juneau Empire)
Ranked choice voting repeal fails by 0.2%, Begich defeats Peltola 51.3%-48.7% on final day of counting

Tally released Wednesday night remains unofficial until Nov. 30 certification.

Looking through the dining room and reception area to the front door. The table will be covered with holiday treats during the afternoon open house. The Stickley slide table, when several extensions are added, provides comfortable seating for 22 dinner guests. (Laurie Craig / Juneau Empire)
The Governor’s House: Welcoming Alaskans for more than 100 years

Mansion has seen many updates to please occupants, but piano bought with first funds still playable.

The language of Ballot Measure 2 appears on Alaska’s 2024 absentee ballots. The measure would repeal the states open primary and ranked choice voting system. (Andrew Kitchenman/Alaska Beacon)
Count tightens to 45-vote margin for repealing Alaska’s ranked choice system going into final day

State Division of Elections scheduled to conduct final tally at 5 p.m. Wednesday.

The drive-through of the Mendenhall Valley branch of True North Federal Credit Union, seen on June 13, is where a man was laying down when he was fatally struck by a truck during the early morning hours of June 1. (Mark Sabbatini / Juneau Empire file photo)
Police: Driver of CBJ truck not at fault in death of man struck in drive-through lane of bank

Victim laying on pavement during early-morning incident in June couldn’t be seen in time, JPD chief says.

Juneau Assembly members confer with city administrative leaders about details of a proposed resolution asking the state for more alcohol licenses during an Assembly meeting Monday night. (Mark Sabbatini / Juneau Empire)
Petition seeking one-third expansion of alcohol-serving establishments gets Assembly OK

Request to state would allow 31 licensees in Juneau instead of 23; Assembly rejects increase to 43.

Noah Teshner (right) exhibits the physical impact military-grade flood barriers will have on properties with the help of other residents at a Juneau Assembly meeting on Monday night. (Mark Sabbatini / Juneau Empire)
Locals protesting $8K payment for temporary flood barriers told rejection may endanger permanent fix

Feds providing barriers free, but more help in danger if locals won’t pay to install them, city manager says.

Low clouds hang over Kodiak’s St. Paul Harbor on Oct. 3, 2022. Economic woes in Alaska’s seafood industry have affected numerous fishing-dependent communities like Kodiak. (Yereth Rosen/Alaska Beacon)
Dire condition of Alaska’s seafood industry has many causes and no easy fixes, experts say

Legislative task force charged with helping communities considering broad range of responses.

Most Read