Late Wednesday night, a massive magnitude 8.2 earthquake shook the Alaska Peninsula, just east-southeast of Perryville. The quake hit around 10:15 p.m. local time on July 28, 2021, with its epicentre roughly 32 km below the ocean floor. (USGS)
This isn’t surprising to experts: the region lies along the subduction zone where the Pacific Plate dives beneath North America, part of the notorious Ring of Fire. While powerful, the quake struck offshore in a sparsely populated area, which limited severe damage and casualties.
Almost immediately, tsunami warnings were issued for Kodiak Island, Aleutian passages, and other coastal communities. Sirens blared, alert systems activated, and Alaska’s Governor confirmed the Emergency Operations Center was fully mobilized. (ASU News, NGDC)
The main tremor triggered multiple aftershocks, some exceeding magnitude 6.0. Scientists warn that such aftershock sequences can continue for weeks or months, especially after an earthquake of this size. (Alaska Earthquake Center)
Residents across southern Alaska felt shaking—light to moderate in Anchorage—with minor cracks or shifted furniture reported. Monitoring buoys recorded only small sea-level changes, often less than a meter, confirming the tsunami threat was limited. Emergency managers downgraded warnings to advisories once data showed no immediate danger.
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