7.9-magnitude earthquake prompts tsunami advisory on Pacific coast

LOS ANGELES (KABC) -- A 7.9-magnitude earthquake struck along the Aleutian Islands in Alaska at 1:53 p.m. PT, prompting a tsunami warning for the U.S. Pacific coast. A preliminary report indicated the quake was a 7.1 magnitude. That was revised minutes later to 8.0 by the U.S. Geological Survey. Later in the evening the magnitude was revised to 7.9.

The warning for Southern California was downgraded to a tsunami advisory by the National Weather Service. The advisory was canceled at 4:53 p.m. PT.

The NWS reported that water was leaving the harbor of the city of Adak, Alaska, at 3:23 p.m. The Adak city manager confirmed to ABC News that water in the harbor was receding and people in that area were heading for higher ground. Adak, the largest city near the epicenter, has about 300 residents.

Monday's quake generated small tsunamis with waves of less than 7 inches, prompting the National Tsunami Warning Center to downgrade the warning to an advisory. Small waves were expected along parts of the Aleutian Islands stretching from Unimak Pass to Attu, and officials advised people to stay off the beaches.

The tsunami advisory for Alaska was canceled at 6:47 p.m. PT.

The earthquake struck 244 miles southeast of Attu Station in Alaska, about 15 miles off Little Sitkin Island, at a depth of 71.1 miles, according to the USGS.

A second earthquake was reported at 2:30 p.m. Los Angeles time. The second quake registered as a 5.9-magnitude temblor, according to the USGS, downgraded from a 6.2 preliminary estimate from the Pacific Coast Tsunami Warning Center.

The Associated Press contributed to this report.