SCIENCE

Chilean Earthquake Moved City Ten Feet

March 9, 2010

The February 27 magnitude-8.8 earthquake in Chile moved the city of Concepción, located 65 miles south of the epicenter, at least 10 feet to the west, according to a new analysis.

Just think about it: There was enough power in that earthquake to move an entire city—people, buildings and all the land underneath—a whole 10 feet in just tens of seconds. Chile's capital, Santiago, 200 miles away, was moved about 11 inches to the west-southwest. Argentina's capital, Buenos Aires, 800 miles away, was moved an inch.

The researchers, who were from Chile, Argentina and the United States, checked the locations of more than two dozen GPS stations across South America and compared the location data from before and after the earthquake. They found movement as far away as the Falkland Islands and Fortaleza, Brazil.

Chile is located on the Pacific Ring of Fire where the Nazca plate is being subducted beneath the South American plate and has had a long history of powerful, destructive earthquakes. The USGS explains:

The written history of very large plate-boundary earthquakes between Valparaíso and Concepción probably begins with a shock near Concepción in 1562. Another earthquake eight years later set off a tsunami that led Spaniards to rebuild Concepción on higher ground. A 1730 earthquake probably centered near Valparaíso generated a tsunami that caused flooding and damage in Japan, as did the great Concepción earthquake of 1751. Charles Darwin and Robert FitzRoy observed the next major Concepción earthquake in 1835. The northern part of the 2010 rupture overlaps with the probable source area of the 1906 Valparaíso earthquake of magnitude 8.2. The tsunami associated with the 1906 earthquake produced damage in Hawaii, with reported run-up heights as great as 3.5 m.

Other parts of Chile’s coast have also produced notable earthquakes. South of Concepción, the source of the 2010 earthquake adjoins a fault rupture nearly 1,000 km long that produced the largest 20th-century earthquake worldwide – the giant 1960 earthquake of magnitude 9.5 An estimated 1600 lives were lost to the 1960 earthquake and tsunami in Chile, and the 1960 tsunami took another 200 lives among Japan, Hawaii, and the Philippines. At Valparaíso, a plate-boundary earthquake of magnitude 8.0 occurred in 1985. North of Valparaíso, a magnitude 8.5 earthquake in 1922 generated a Pacific Ocean tsunami that reached heights of 9 m on the Chilean coast near Coquimbo and washed away boats in Hilo harbor, Hawaii. Still farther north along the coast of Chile and Peru, great earthquakes with trans-Pacific tsunamis occurred are known from 1586, 1687, 1868, and 1877. Overall along the Chilean coast there have been 13 earthquakes of magnitude 7.0 or greater since 1973.