The massive 8.8 magnitude earthquake that struck Chile more than a week ago moved the city of Concepción at least 10 feet (3 meters) to the west, seismological measurements indicate.
The violent temblor - the fifth most powerful quake ever measured - shifted other parts of South America as well, from the Falkland Islands (located just east of the southern tip of South America) to Fortaleza, Brazil, situated on that country's northern coast.
The quake occurred off the coast of the Maule region of Chile in one of Earth's seismic hotspots where the Nazca tectonic plate is squeezed under, or subducted below, the neighboring South American plate. Tension builds up as the plates move against each other, and earthquakes such as the one that struck Chile on Feb. 27 relieve these pent-up stresses.
The movements of the Earth during earthquakes can be measured by comparing the precise GPS locations of instruments prior to the quake and then after. ...