Los Angeles, US: The massive magnitude 8.8 earthquake that struck off the coast of Chile last month moved the entire city of Concepción, the closest urban area to the quake’s epicentre, at least 10 feet west. The results were obtained from precise global positioning satellite (GPS) measurements taken before and after the quake, which occurred off the Maule coast of Chile, according to scientist Mike Bevis of Ohio State University.
It also changed the speed at which the Earth spins, prompting NASA scientists to estimate that the day was shortened by a millionth of a second. Chile’s capital, Santiago, moved about 11 inches to the west-southwest, while Buenos Aires, all the way across the continent from the quake site, moved about an inch to the west, the researchers said. The cities of Valparaiso and Mendoza, Argentina, both northeast of Concepción, also moved significantly.
The quake region is in the Pacific Ring of Fire. The February tremor occurred when the Nazca tectonic plate, which lies under much of the Pacific Ocean, was forced under the South American tectonic plate, a process known as subduction. The lifting of the South American plate as it rode over the Nazca plate was responsible for the tidal wave that did considerable damage along the South American coast.
Some experts do mention that there is nothing unusual about the latest spate of earthquakes in Haiti, Chile and now Turkey, according to a report by the Seattle Times. Seismologists said that although one powerful quake can conceivably raise the risk for others elsewhere, the recent string of quakes is probably just coincidence. On average, there are 134 earthquakes a year that have a magnitude between a 6.0 and 6.9, according to the U.S. Geological Survey. This year is off to a fast start with 40 so far — more than in most years for that period of time.
Source: Seattle Times