Large Earthquake Hits Chile, Generates Tsunami Across Pacific

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Shakemap of the Feb. 27, 2010 earthquake that struck off the coast of Chile. (Credit: Image courtesy of USGS)

ScienceDaily (Feb. 27, 2010) — An 8.8 magnitude earthquake struck off the coast of central Chile early morning on Saturday, February 27, 2010 at 3:34 a.m. local time, about 200 miles southwest of the Chilean capital of Santiago, killing several hundred people and exposing millions of people to strong shaking that toppled many buildings.

Tsunami warnings were issued for Hawaii, as well as Australia, New Zealand, Indonesia, Japan, and other countries along the Pacific coastline, as the giant waves triggered by the earthquake reverberated through the entire ocean.

This earthquake occurred at the boundary between the Nazca and South American tectonic plates. The two plates are converging at a rate of 80 mm per year. The earthquake occurred as thrust-faulting on the interface between the two plates, with the Nazca plate moving down and landward below the South American plate.

Coastal Chile has a history of very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. The February 27 shock originated about 230 km north of the source region of the magnitude 9.5 earthquake of May, 1960 -- the largest earthquake worldwide in the last 200 years or more. This giant earthquake spawned a tsunami that engulfed the Pacific Ocean. 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.

Approximately 870 km to the north of the February 27 earthquake is the source region of the magnitude 8.5 earthquake of November, 1922. This great quake significantly impacted central Chile, killing several hundred people and causing severe property damage. The 1922 quake generated a 9-meter local tsunami that inundated the Chile coast near the town of Coquimbo; the tsunami also crossed the Pacific, washing away boats in Hilo harbor, Hawaii.

The magnitude 8.8 earthquake of February 27, 2010 ruptured the portion of the South American subduction zone separating these two massive historical earthquakes.

A large vigorous aftershock sequence can be expected from this earthquake.

Story Source: The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by U.S. Geological Survey/Earthquake Hazards Program.