7.3-magnitude quake strikes off Alaska

LOS ANGELES - A 7.3-magnitude earthquake struck off the coast of the US state of Alaska on July 16, triggering a tsunami warning that was later withdrawn, the US Geological Survey said.

The earthquake took place at approximately 12.37 local time (4.37am on July 17 in Singapore), with its epicentre located about 87km south of the island town of Sand Point, USGS said. The epicentre had a relatively shallow depth of 20.1km.

Authorities initially issued a tsunami warning for South Alaska and the Alaska peninsula after the quake, but later downgraded it to a tsunami advisory, and then withdrew it entirely.

“The Tsunami Advisory is cancelled for the coastal areas of South Alaska and the Alaska Peninsula,” said the National Tsunami Warning Center (NTWC) in a message issued about two hours after the earthquake.

The initial quake was followed by a cluster of more than a dozen aftershocks, the largest of which was measured at 5.2-magnitude, according to USGS.

The tsunami warning and advisory had only been issued for areas along the Alaskan coast, with areas further afield unaffected, the NTWC said.

A tsunami with a maximum height of 6.1cm was observed at Sand Point, it said.

Nevertheless, the centre advised residents in the affected zone to be aware of hazards.

“Do not re-occupy hazard zones until local emergency officials indicate it is safe to do so,” the NTWC said.

Alaska is part of the seismically active Pacific Ring of Fire.

The remote state was hit by a 9.2-magnitude earthquake in March 1964, the strongest ever recorded in North America.

It devastated the city of Anchorage and unleashed a tsunami that slammed the Gulf of Alaska, the US west coast, and Hawaii, killing scores and causing more than US$400 million in property loss.

A 7.2-magnitude quake hit off the Alaskan peninsula in July 2023, with no major damage reported following the tremor. AFP