Chile earthquake of 2010 , severe earthquake that occurred on February 27, 2010, off the coast of south-central Chile , causing widespread damage on land and initiating a tsunami that devastated some coastal areas of the country. Together, the earthquake and tsunami were responsible for more than 500 deaths.

Earthquake and tsunami

The magnitude-8.8 earthquake struck at 3:34 am. The epicentre was located some 200 miles (325 km) southwest of the Chilean capital of Santiago, and the focus occurred at a depth of about 22 miles (35 km) below the surface of the Pacific Ocean. The earthquake—resulting from the rupture of a 300- to 375-mile (500- to 600-km) stretch of the fault that separates the South American Plate from the subducting Nazca Plate—was felt as far away as São Paolo, Brazil, and Buenos Aires, Argentina. A 2014 study contended that water pressure built up between the two plates had been the catalyst. The initial event was succeeded in the following weeks by hundreds of aftershocks, many of them of magnitude 5.0 or greater. The temblor was the strongest to strike the region since the magnitude-9.5 event of 1960, considered to be the most powerful earthquake ever recorded. (See Chile earthquake of 1960.)

Chile earthquake of 2010 Map depicting the intensity of shaking experienced during the Chile earthquake, Feb. 27, 2010. Encyclopædia Britannica, Inc.

Because the region’s violent tectonic history had made it a focus of seismological study and monitoring, extant GPS sensors installed in Chile and neighbouring countries allowed the detection of subtle shifts in the location of cities, including Concepción and even Buenos Aires, as a result of the quake. A NASA computer model ascertained that the powerful force of the subducting plate had shifted Earth’s axis sufficiently to shorten the day by more than a microsecond. A study of the aftershocks released in 2014 indicated that two anomalously dense rock structures beneath the South American Plate, previously undetected, had likely slowed the rupture and, as a result, intensified shaking at the surface.

Stress brought on by the convergence of the two tectonic plates caused rocks to shatter along the boundary between them. This forced a portion of the seabed upward, displacing the water above and triggering a tsunami. The Chilean town of Constitución was inundated by waves as high as 50 feet (15 metres), and the port of Talcahuano was damaged by a wave measuring nearly 8 feet (2.4 metres) high. Traveling across the Pacific Ocean at nearly 450 miles (725 km) per hour, the tsunami encountered the Juan Fernández Islands, located approximately 420 miles (675 km) off the coast of Chile. Although observers on the largest of the Juan Fernández Islands reported waves as high as 10 feet (3 metres), the tsunami weakened significantly before it reached the coasts of California, Hawaii, New Zealand, and Japan over the next several hours.

Chile earthquake; Talcahuano Boats run aground by the 7.7-foot (2.3-metre) tsunami that resulted from a magnitude-8.8 earthquake two days before, downtown Talcahuano, Chile, March 1, 2010. Martin Bernetti—AFP/Getty Images

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A study published in August 2014 noted that the temblor triggered small earthquakes in Antarctica. It was the first direct evidence that earthquakes could trigger secondary seismic events in the Antarctic’s ice sheets.