A magnitude 7.9 earthquake in the Gulf of Alaska triggered a series of tsunami alerts early Tuesday from southern Alaska down the western coast of North America, prompting warnings in some low-lying communities for people to seek higher ground.
But initial fears that such a massive tremor could unleash destructive waves that could hit coastal Alaska or Hawaii or ripple even farther subsided within four hours. There were no immediate reports of injuries or property damage.
Eddie Athey, a fire chief in the cruise ship town of Seward, Alaska, told The Associated Press that the quake lasted for about 90 seconds and "felt like the washer was off balance." He praised his community for taking part in a "controlled evacuation."
The quake struck at 12:31 a.m. local time (4:31 a.m. ET) about 181 miles southeast of Kodiak, Alaska, at a depth of about 6.5 miles, the Alaska Earthquake Center said. The quake's strength was later revised downward from an initial reading of 8.2 magnitude. At least 17 aftershocks were recorded with magnitudes in the 4 to 5 range, the center tweeted.
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A tsunami watch issued early Tuesday for coastal areas from Washington state to California was canceled nearly three hours after the quake. Tsunami watches were also eventually canceled for the Canadian province of British Columbia and Hawaii, as well as advisories for southern Alaska after 4 a.m. local time (8 a.m. ET), according to the National Weather Service's National Tsunami Warning Center.
The earliest wave was predicted to have reached Kodiak at 1:45 a.m. local time (5:45 a.m. ET), and warning sirens sounded over the town of more than 6,100 people.
Kodiak police said just before 2:30 a.m. local time (6:30 a.m. ET) that officers reported water was receding from the harbor.As a precaution, state police in Kodiak advised residents on lower ground to move higher, and that a local high school was being opened as a shelter.
Mike Tvenge, Kodiak's city manager, said harbor masters were continuing to monitor water levels, according to NBC affiliate KTUU. School was canceled Tuesday out of precaution.
"We're very grateful that there wasn't a tsunami of any kind of magnitude," said Mayor Pat Branson.
A buoy located 188 nautical miles southeast of Cordova, Alaska, recorded a wave of about 30 feet around the time of the earthquake, according to NOAA data. But the report appeared to be an anomaly and it was unclear if it was related to the quake.
"We know one of the buoys showed a significant water rise right next to where the earthquake happened, but the next buoy didn't seem to experience that," NBC News meteorologist Bill Karins said. "We don't know yet what this means. It could have malfunctioned. We just don't know at this stage. It's too early to tell."
Police in Anchorage, the largest city in Alaska, said residents there were not covered by the earlier tsunami warnings and were outside the danger zone.
Kodiak officials said they were grateful no one was hurt.
"We live in a very prone earthquake and tsunami area," Branson said, according to KTUU. "It's a beautiful place, but that's what you have when you live in paradise."