Chile quake moves worst-hit Concepcion three metres to the west

Mar 9, 2010, 19:55 GMT

New York - The massive magnitude 8.8 earthquake that hit Chile last month moved the city of Concepcion about three metres to the west and also shifted several other cities in South America, scientists said Tuesday.

Chile's capital Santiago moved 28 centimetres to the west- southwest, according to studies by four universities and several organizations in the United States and Argentina. In Argentina, Buenos Aires moved 2.5 centimetres to the west, the researchers said.

Other cities that moved 'significantly' were Valparaiso and Mendoza in Argentina, which are situated north-east of Concepcion, the city worst-hit by the quake that experienced large-scale destruction.

Officials have recovered nearly 500 bodies of people killed by the quake and resulting tsunami, Chilean officials have said.

Chile sits along the 'ring of fire' that has been known for major seismic stresses caused by continental plates that come together at fault zones encircling the Pacific Ocean. The earthquake struck February 27 when the Nazca tectonic plate was squeezed below the South American plate. Geophysicists and researchers believe the earthquake was the fifth most powerful recorded since instruments were available to measure quakes.

The researchers, including many on the ground in Chile, deduced the geological movements in cities that have shifted by comparing precise global positioning satellite (GPS) data 10 days after the Chilean earthquake.

Ohio State University, which contributed to the studies, called for increasing the number of GPS stations in the central and southern Andes, where the university's Mike Bevis has led a project to measure crustal motion and deformation of mountain chain. The project called the Central and Southern Andes GPS Project (CAP) hopes to triple to 25 the number of GPS stations spread across the region.

'By re-occupying the existing GPS stations, CAP can determine the displacements, or 'jumps' that occurred during the earthquake,' Bevis said. 'By building new stations, the project can measure the post- seismic deformations that are expected to occur for many years, giving us new insights into the physics of the earthquake processes.'

Ben Brooks, a researcher at the School of Ocean and Earth Science and Technology at the University of Hawaii, said the Chile earthquake offered a 'unique' opportunity to better understand the seismic processes that cause earthquakes.

The US Geological Survey has reported hundreds of aftershocks, many exceeding magnitude 6.0 or greater, since the initial quake, drawing researchers around the world to South America to study the phenomena.