Chile aftershocks could go on for years: scientists

"The larger the earthquake, the larger the aftershocks, the more of them and the longer they're going to last," said John Bellini, a geophysicist at the US Geological Survey (USGS) in Colorado.

"They will wind down in number, but they will probably be noticeable to people for months and could go on possibly for years," he told AFP.

Chile has been rattled by more than 200 aftershocks since the historic monster quake struck the South American country six days ago, killing some 800 people as buildings collapsed and tsunamis swept people to sea.

Several have topped 6.0 on the Richter scale, including Friday's three tremors, which were powerful enough to cause already damaged buildings to collapse.

The aftershocks in Chile were "not more numerous than expected but because of the large size of this earthquake, they are much larger in size than normal aftershocks," said Bill Herbert, a professor of geophysics at the University of Pittsburgh.

In Haiti, where a 7.0-magnitude reduced much of the capital Port-au-Prince to rubble in January and claimed over 200,000 lives, experts estimate there have been "dozens" of aftershocks, not hundreds as in Chile.

"One reason is because the Chile earthquake was a lot bigger than the quake in Haiti -- it released about 500 times more energy," explained USGS geophysicist Jessica Sigala.

"It's a lot of energy that's released, and the Earth is trying to get back to normal. In order to do that it's still moving, and that's what the aftershocks are."

Scientists believe aftershocks could still be occurring years after the 9.1-earthquake off the coast of Sumatra in Indonesia in 2004, which triggered a deadly tsunami that killed around 200,000 people in south Asia.

"There was a 9.1 that happened in December 2004 and then there was an 8.6 that happened in March 2005, and occasionally today, we'll see an earthquake in that area that may be an aftershock from the one that happened in 2004," Sigala said.

Hours afer Sigala had spoken to AFP, a 6.5-magnitude quake struck off the coast of Sumatra.

(c) 2010 AFP