A powerful 8.2-magnitude earthquake struck off the southern coast of Alaska late Wednesday night, prompting a tsunami warning for parts of the state and a tsunami watch as far as Hawaii. They were lifted within hours.
The earthquake was detected about 75 miles southeast of Chignik, Alaska, about 10:15 p.m. local time, the United States Geological Survey said.
The earthquake was felt throughout the Alaska Peninsula and on Kodiak Island, the Alaska Earthquake Center reported. In Kodiak, tsunami sirens blared and people began moving to higher ground as word of the warning spread.
There were no immediate reports of damage.
The alert issued by the National Tsunami Warning Center was in effect for about two hours across south Alaska and the Alaska Peninsula and the Aleutian Islands.
A tsunami watch was also briefly issued for Hawaii and canceled a little over an hour later, Gov. David Ige said on Twitter. The National Weather Service office in Beach, Hawaii, had warned that “widespread hazardous tsunami waves are possible,” based on preliminary measurements of the quake.
The earthquake recorded on Wednesday was one of only 17 since 1990 of 8.2 magnitude or higher, according to U.S.G.S. data.
There were at least two dozen aftershocks recorded in Alaska, the U.S.G.S. said. One of the largest, about 70 miles south southeast of Perryville, measured a 6.1.
Earthquakes in Alaska are not uncommon. The Alaska Earthquake Center reported more than 49,000 seismic events in the state and nearby regions in 2020. The center also said Alaska recorded last year’s most powerful and third-most powerful earthquakes worldwide.
A tsunami is defined as a series of waves caused by a large or sudden displacement of the ocean, the Weather Service said. The waves radiate outward in all directions from the disturbance and can move across ocean basins. The majority of tsunamis are caused by large earthquakes below or near the ocean floor.
There have been at least four notable tsunamis in Alaska, including one in 1958 in Lituya Bay caused by a mountain slide, killing five. In 1964 a tsunami in Southern Alaska caused by an earthquake killed 106.