The strong quake was followed by several aftershocks and another big temblor with a magnitude of 6.3 some three hours later, officials said.

There were no initial reports of casualties or damage, but media reports said the first quake was felt in a wide area of central Chile, where some residents evacuated coastal areas as a precaution.

The US Geological Survey and Chile's National Emergency Office (ONEMI) said the quake occurred in the Pacific some 70 kilometers (45 kilometers) from the city of Concepcion.

The USGS initially reported a major 7.0 magnitude, and later revised that to 6.8, which can still cause devastation.

The quake struck at 2005 GMT near a region in central Chile that was heavily damaged by an 8.8 magnitude earthquake and tsunami on February 27, 2010.

The epicenter of the smaller quake, which occurred at 2339 GMT, was about 55 kilometers (34 miles) southwest of Concepcion.

After the first quake, Rodrigo Ubilla, an Interior ministry official, said there were no casualties or damage to buildings reported and praised the "exemplary" reaction of the population, saying the people showed "maturity" after last year's catastrophe.