8.3 magnitude quake shakes Chile capital, causes buildings to sway

SANTIAGO, Chile (KGO) -- A powerful earthquake has shaken Chile's capital, causing buildings to sway and people to take refuge in the streets.

The U.S. Geological Survey reports the quake had a preliminary magnitude of 7.9 and then upgraded it to an 8.3. This is considered a great quake, capable of extreme damage.

U.S. officials say the quake was centered about 153 miles north-northwest of Santiago.

At least one person has died.

8.3 earthquake rocks Chile, sets off tsunami advisory for Calif.

The initial earthquake was followed by at least five aftershocks, the strongest a 6.4.

The state of Hawaii is under a tsunami watch.

A tsunami advisory is in effect for coastal areas of Southern Calif. from San Onofre State Beach, which is south of Los Angeles, to Ragged Point Calif., which 50 miles northwest of San Luis Obispo. People are advised to move off beaches and out of harbors and marinas. The first tsunami waves are expected to arrive around 4:45 a.m. Thursday.

"There is a tsunami watch for a large portion of the Pacific basin, excluding the California coast and U.S. West Coast. Hawaii has a tsunami watch in place," said USGS geophysicist Ole Kaven.

The UC Berkeley Seismological Lab is measuring the quake in Chile. Richard Allen, the director of the lab, said it was a shallow earthquake that hit right on the subduction zone. "There's also a serious tsunami threat asscoated with this and we're beginning to see some evidence that there actually is a tsunami," Allen said.

Stay with ABC7 News for details on this developing story.

The Associated Press contributed to the story.