The 8.8 magnitude earthquake that shook Chile Feb. 27, 2010, moved the entire city of Concepcion at least 10 feet to the west, according to preliminary measurements. It shifted other parts of South America, from the Falkland Islands to Fortaleza, Brazil, as well, moving Santiago, Chile, about 11 inches to the west-southwest and Buenos Aires, Argentina (across the continent from the quake’s epicenter) about 1 inch to the west.
The data gathered by researchers from four universities and several agencies, including geophysicists on the ground in Chile, paint a much clearer picture of the power behind this temblor, believed to be the fifth-most-powerful since instruments have been available to measure seismic shifts.
Quakes relieve pent-up geologic pressure in convergence zones around the “ring of fire” that encircles the Pacific Ocean. The February Chilean quake occurred where the Nazca tectonic plate was squeezed under, or subducted below the adjacent South American plate.
Benjamin Brooks, associate researcher with the University of Hawaiʻi at Mānoa’s School of Ocean and Earth Science and Technology is co-principal investigator with Ohio State University’s Mike Bevis on a 17-year study measuring crustal motion and deformation in the central and southern Andes.
With global positioning satellite location data, the February 2010 event, tragic as it was, “will arguably become one of, if not the most important great earthquake yet studied,” Brooks says.
Monitoring postseismic deformations provides new insights into the physics of the earthquake process. James Foster, from UH Mānoa’s Pacific GPS Facility, is part of the GPS processing effort.