Alaskans were left panicked after they were jolted awake overnight Tuesday by a powerful earthquake in the Gulf of Alaska – then by sirens that warned of a possible tsunami. A magnitude 7.9 earthquake struck at 12:32 a.m. off the Alaska coast. The quake itself was far enough away not to cause major damage but occurred in an area that triggered a potential tsunami.
Evacuation sirens blared “Attention, a tsunami warning has been issued for this area,” officials warned over loudspeakers. “The National Weather Service’s Tsunami Warning Center has advised that widespread hazardous tsunami waves are possible.” That warning covered not only most of coastal Alaska, but also the entire coast of British Columbia. Tsunami watches were posted from Washington state to California — and even Hawaii and as far away as American Samoa.
Within minutes, the roads in the seaside town of Kodiak, Alaska, were filled cars heading to higher ground. Residents of Kodiak were asked by police to move at least 100 feet above ground as a precaution. For two hours, many braced for the worst but by 4 a.m. — less than four hours after the quake hit — all warnings were lifted. The only tsunami was an 8-inch wave in Kodiak.
Around 4 a.m. local time, officials canceled tsunami warnings for coastal areas of South Alaska, the Alaska Peninsula and the Aleutian Islands. Warnings were also called off for Hawaii and the Oregon, Washington, British Columbia and California coasts. Tsunami warnings were later canceled in other parts of South Alaska and the Alaska Peninsula, specifically the coastal areas from Hinchinbrook Island, about 90 miles east of Seward, to Chignik, Alaska.
The US Geological Survey (USGA) said the earthquake was located in an area south of where the Pacific tectonic plate converges with the North America plate and at a depth of about 12 miles. Research geophysicist for USGA Will Yeck said the quake occurred on a fault within the Pacific plate that had not been previously charted and the area that ruptured is approximately 140-by-30 miles. Yeck said there have been at least 30 aftershocks from the initial quake, the largest being a magnitude 5.3.
From Indonesia, to Japan, to Hawaii and Alaska, the entire region sits in what is known as the Pacific Ring of Fire – an extremely volatile chain of active volcanoes, tectonic plates and earthquake zones. Most of the world’s earthquakes happen in this region. That’s the same spot which saw the second largest earthquake ever recorded: A 9.2 magnitude in March 1964 that caused widespread destruction and death in Alaska. That earthquake occurred over an area measuring 155 miles wide by 500 miles long. The epicenter was about 12 miles north of Prince William Sound, and 75 miles from Anchorage, the state’s largest city.