Earthquake strikes off coast of Alaska

AN EARTHQUAKE with a magnitude of 7.9 struck near the coast of Alaska with officials initially issuing a tsunami warning.

The National Tsunami Centre has since cancelled the tsunami warning.

The quake, which struck at 8:31pm AEDT, hit 256km southeast of Chiniak, on the southern Alaskan coast, at a depth of 10km, the US Geological Survey says.

The quake initially prompted a tsunami warning for parts of Alaska and Canada and a tsunami watch for the entire US west coast and Hawaii.

The tsunami watch was later cancelled in Canada and the US.

The US Geological Survey also revised a preliminary estimate of 8.2 magnitude

Lt. Tim Putney of the Kodiak Police Department said: “We haven’t seen anything yet or had any reports of a wave.”

The earthquake woke Lt. Putney up out of a dead sleep, and he estimates it shook for at least 30 seconds.

“I’ve been Kodiak for 19 years that was the strongest, longest lasting one I’ve ever felt,” he said by telephone.

US Geological Survey seismologist Paul Earle said the Alaska earthquake was a type that usually produces less vertical motion, which means less chance for waves to build for a tsunami.

He says the earthquake was within the Pacific plate and was a so-called “strike- slip earthquake.”

That’s the type when one side of the fault slides past another fault, like the San Andreas fault in California.

In the Alaska earthquake, Mr Earle says one side went more to the east and one side went more to the west.

He says that’s somewhat unusual because quakes in the area are usually thrust earthquakes where one side goes underneath the other.

He says those are the type that cause more vertical motion and increase the chance for a tsunami.

The Alaska quake was the planet’s strongest since an 8.2 in Mexico in September.