Magnitude-7.9 Alaska quake spawns small tsunami

By Mark Thiessen, Associated Press

Published Monday, June 23, 2014 | 2:33 p.m.

Updated Monday, June 23, 2014 | 6:12 p.m.

ANCHORAGE, Alaska — A strong earthquake near Alaska's Aleutian Islands triggered a tsunami warning Monday, but only small waves measuring several inches hit coastal communities.

The National Tsunami Warning Center, which initially issued a warning that significant inundation was possible, kept advisories in place for parts of the sparsely populated islands, saying conditions could be dangerous to people near the water.

"There could be strong currents, but still stay away from the beach," said Dave Nyland, a geophysicist at the warning center.

The magnitude-7.9 earthquake struck early Monday afternoon, centered about 13 miles southeast of Little Sitkin Island, or about 1,400 miles southwest of Anchorage.

There were no reports of damage, said Jeremy Zidek, a spokesman for the Alaska Department of Homeland Security and Emergency Management.

Residents in some communities like Adak, which were first in line for the tsunami, did evacuate.

"We're seeing water leave our bay, so we do have everybody up on the Bering Hill area, where our primary evacuation center is at," City Manager Layton Lockett told The Associated Press by telephone as he gathered some paperwork before heading out to join about 300 residents at the center.

After the warning was canceled, he said everyone in town remains on alert. If anything significant were to happen, a siren will sound.

"We will expect everyone to go back on the hill ASAP," he said.

About 200 miles west, a tsunami wave of about 7 inches was reported at Amchitka Island, Zidek said. The wave diminished the further it traveled, reaching only a couple of inches at Adak and Shemya.

But the earthquake was widely felt in Adak, one of the largest cities in the affected area. Shaking could also be felt in Shemya and other villages along the island chain.

Lockett said the prolonged shaking from the temblor put it in the top 10 of those felt recently.

"Everybody in our building went out, watching the vehicles shake and waiting for it to end," he said.

Shemya Island is where the U.S. military operates Eareckson Air Station, which serves mainly as an early warning radar installation. Air Force officials said there was no damage to the air station.

Amchitka Island is where the government tested nuclear weapons underground in the 1960s and 70s. The tests included one of the United States' largest nuclear explosions.

Monday's earthquake was initially reported with a magnitude of 7.1, but that was upgraded to 8.0, said Natasha Ruppert, a seismologist with the Alaska Earthquake Center. In the review of data hours after the quake, the magnitude was downgraded to 7.9.

There were several strong aftershocks, with magnitudes ranging from 3.5 to 5.9. Nyland said those would be too small to trigger a tsunami.

A tsunami advisory remained in effect late Monday afternoon for coastal areas between Nikolski and Attu, which is near the tip of the Aleutians.

A separate advisory stretching from Nikolski to Unimak Pass, which is further east, was canceled. That area includes Unalaska, a community of about 4,000 people and home to Dutch Harbor, one of the nation's largest fishing ports.

An advisory means strong currents or dangerous waves are expected, but widespread inundation isn't likely.

Associated Press reporter Ed Donahue in Washington, D.C., contributed to this report.