Tsunami advisory, issued after 7.9 Alaska earthquake, is canceled

A tsunami warning in effect for the coastal areas of Alaska after a 7.9 magnitude earthquake was downgraded to an advisory and then canceled altogether Monday afternoon.

Tsunami waves in the Alaskan cities of Unalaska and Saint Paul were expected to be less than a foot tall, the the National Weather Service advisory said. Small waves have already reached other locations in Alaska and none were higher than 0.6 feet, it said.

Soon after the warning was issued, people headed for higher ground in Adak, Alaska, because water was leaving the harbor, according to a tweet from the National Weather Service Alaska Region.

“When there’s a significant earthquake such as this, we have a tsunami siren” similar to a tornado alarm,” City Manager Layton Lockett told the Los Angeles Times. “It just blares,” and people know to head to safety.

Adak is home to about 130 permanent residents and 80 contractors, and in these situations, having a small population comes in handy, Lockett said: “Everybody knows everybody, so if you don’t see somebody, you can call them real quick or go get them.”

Based on federal and state data and their own observations, Adak’s mayor, police chief and city manager decided later in the afternoon to call off the evacuation.

The first tsunami waves were expected to hit Shemya, a small island in the Aleutian chain, at 2:25 p.m. PDT. But a spokesman at the Air Force’s Alaska command said no personnel there had been hurt and no equipment damaged.

The temblor struck 25 miles northwest of Amchitka at 12:53 p.m., the National Weather Service said Monday.

The earthquake was initially reported as having a magnitude of 7.1, then upgraded to 8.0 and later downgraded to 7.9 by the U.S. Geological Survey.

The tsunami warning covered parts of the Aleutian Islands from the Unimak Pass to Nikolski. California, Oregon, Washington and Hawaii were not considered to be at risk.

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