US: Chilean earthquake attracts scientific interest

Last month's massive earthquake in Chile may have been the fifth-largest since instruments were available to measure such events, but it could well become the most important large quake thanks to the information scientists are gaining from it.

The earthquake measured 8.8 on the Richter scale and while the people of Chile continue their clean-up after the 27 February disaster, scientists are continuing their own work in its wake.

Already researchers have found that the quake moved the city of Concepcion at least three metres to the west, and shifted other parts of South America as far afield as the Falkland Islands and Fortaleza, Brazil. In Argentina, Buenos Aires moved about 2.5 centimetres west.

The measurements are preliminary and come from information gathered by researchers from four universities and several agencies, including geophysicists in Chile.

They calculated the cities' movement by comparing precise GPS (global positioning satellite) locations known prior to the major quake to those almost 10 days later.

The research team are among the scientists studying the impact of the quake and are part of a scheme known as the Central and Southern Andes GPS Project, or CAP, which measures crustal motion and deformation in the Central and Southern Andes.

Ben Brooks, an associate researcher with the school of ocean and earth science and technology at the University of Hawaii and co-principal investigator on the project said the event, tragic as it was, offered a unique opportunity to better understand the seismic processes that control earthquakes.

"The Maule earthquake will arguably become one of the, if not the most, important great earthquakes yet studied. We now have modern, precise instruments to evaluate this event and, because the site abuts a continent, we will be able to obtain dense spatial sampling of the changes it caused.

"As such, the event represents an unprecedented opportunity for the earth science community if certain observations are made quickly and comprehensively," Brooks said.

Mike Bevis, professor of earth sciences at Ohio State University, has led the CAP since 1993 and hoped to as much as triple its current network of 25 GPS stations spread across the region.

"By reoccupying 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 monitor the post-seismic deformations that are expected to occur for many years, giving us new insights into the physics of the earthquake process."