A magnitude-7.1 earthquake has shaken southern Chile, frightening hundreds of people who fled for higher ground fearing it could generate a tsunami like the one that ravaged the coastline last year.
There were no immediate reports of deaths or damage, and Vicente Nunez, head of the National Emergency Office, said no tsunami alert was issued.
The Pacific Tsunami Warning Centre in Hawaii said a destructive Pacific Ocean-wide tsunami was not expected but noted the risk of local tsunamis.
The latest USGS report revised an earlier report giving the magnitude of the quake as 7.2, and the depth at 33 kilometres, and describing the location as offshore from the Bio-bio region, which was devastated last year by a massive earthquake.
Based on all available data a destructive Pacific-wide tsunami is not expected, the Pacific Tsunami Warning Centre said in a bulletin.
However, earthquakes of this size sometimes generate local tsunamis that can be destructive along coasts located within a hundred kilometres of the earthquake epicentre, it said.
When the first quake struck, people in several coastal cities quickly moved for higher ground, abandoning some shopping centres entirely.
Some mobile-phone communications were knocked out in the Araucania region.
The US Geological Survey reported at least one aftershock of 5.0 magnitude.
Residents of the region have fresh memories of the magnitude-8.8 quake and resulting tsunami on February 27, 2010, that killed about 520 people and left 200,000 homeless