The tremblor struck around 50 miles south of Perryville, a small town of 100 or so people around 500 miles to the south and west of Anchorage, according to Robert Sanders, a United States Geological Survey geophysicist.
“There could be damage and injuries from an event of this magnitude,” he told NBC News, adding that the sparsity of the population mitigated that risk but did not remove it.
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Tsunami warnings were put in place for parts of south Alaska, the Alaska Peninsula and the Aleutian Islands by the National Tsunami Warning Center. A tsunami advisory was also issued for southeast Alaska, but the National Weather Service said there was no tsunami threat to Anchorage.
The Alaska Division of Homeland Security and Emergency Management tweeted that the State Emergency Operations Center "had been activated and is calling communities in the tsunami warning area."
The warnings were later canceled, but the NTWS warned in a tweet that "strong and unusual currents may continue for several hours."
A tsunami watch was also issued for Hawaii by the Pacific Tsunami Warning Center, although it was also later canceled.
Sanders said the earthquake was initially measured at 7.2 magnitude but later revised up to 8.2. That was not “an uncommon occurrence,” he said.
Two other earthquakes with preliminary magnitudes of 6.2 and 5.6 occurred in the same area within a half-hour of the first one, the USGS reported.
He added that in July 2020 a 7.8 magnitude earthquake happened in the same region.