Chile quake occurred in zone of increased geological stress

region, which “comes within five kilometers of Port-au-Prince,” he said.

The latest Chile quake, which had killed more than 700 people as of Mar. 1, was centered some 65 miles west-southwest of Talca, Chile, about 21.7 miles below the ocean’s surface, “relatively shallow for a subduction quake,” said Lin. It struck about 200 miles southwest of Santiago, the country’s capitol. Saturday’s earthquake had a “much longer” rupture zone — 500-600 km — than that of the Haiti quake — 35-50 km, Lin said. “So why was the Haiti quake so much more catastrophic than the Chile quake?” he asked. “First, as a nation, Chile is much better prepared for earthquakes than Haiti. People in Chile today still remember the pain of the 1960 quake,” Lin said.

In addition, coastal Chile has a history of other very large earthquakes. Since 1973, there have been 13 events of magnitude 7.0 or greater. Approximately 870 km to the north of the 27 February earthquake is the source region of the magnitude 8.5 earthquake of November 1922. That great quake significantly killed several hundred people and caused 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.

“In contrast, the last catastrophic earthquake in Haiti was 240 years ago,” Lin said, “and thus few people were aware of a string of ‘earthquake bombs’ lying next to Port-au-Prince until Jan. 12.”

“Second,” he said, “the economy of Chile is much better than that of Haiti. Thus, building codes are better developed and enforced in Chile. The contrasts between the aftermaths of the Chile and Haiti quakes reminded us, once again, that ‘earthquakes do not kill people, buildings do.’”

The Chile temblor dispatched tsunami waves onshore to Chile and across the Pacific Ocean toward Hawaii and the west coast of the U.S. mainland, primarily California, and experts warned that tsunami waves were likely to hit Asian, Australian and New Zealand shores within twenty-four hours of the earthquake. Waves 6 feet (1.8 meters) above normal hit Talcahuano near Concepcion 23 minutes after the quake, and President Michelle Bachelet said a huge wave swept into a populated area in the Robinson Crusoe Islands, 410 miles (660 kilometers) off the Chilean coast. There were no immediate reports of major damage from the waves.

Though the predicted tsunami waves did reach Hawaii, California, New Zealand, and other Pacific Rim regions, they proved to be relatively small and had minimal impact. “Even though the waves turned out to be not devastating”, Lin said, “it was an important opportunity for communities in coastal regions to improve the preparedness for potential greater tsunamis in the future.”

The WHOI research vessel Atlantis was operating off the coast of northern Chile when the magnitude 8.8 earthquake struck on Saturday. WHOI confirmed that R/V Atlantis and all on board are safe. There were no ill effects to R/V Atlantis or those on board from the quake or the subsequent tsunami.

R/V Atlantis has a scheduled port stop beginning on 3 March 2010, in Arica, Chile, which is on the northern coast of Chile. The WHOI Marine Operations Department is assessing the situation with their port agents to determine how or if that port stop will be affected.

A number of WHOI staff are onboard the R/V Melville, operated by Scripps Institution of Oceanography, which is conducting research at the Chile Triple Junction. WHOI received an e-mail from an employee onboard the ship, and was told that all onboard are fine. The blog associated with this expedition had not been updated on Saturday because, WHOI was told, the ship’s communication capability was being used to communicate by those onboard with family on shore.