| SANTIAGO, Chile |
Hundreds of thousands of people evacuated from Chile's low-lying coastal areas returned home Wednesday morning after authorities called off a tsunami alarm as damage from a massive overnight earthquake seemed mostly limited.
The major earthquake, with a magnitude 8.2, struck off the coast of northern Chile on Tuesday, killing six and triggering a tsunami that pounded the shore with 7-foot waves.
Officials said the dead included people--a firefighter among them--who were crushed by collapsing walls or were killed by heart attacks.
Angamos, a key copper exporting port in northern Mejillones, escaped major damage, but workers were evacuated as a precaution, port union leader Enrique Solar told Reuters.
The U.S. Geological Survey said the quake was shallow at 12.5 miles below the seabed and struck about 950 miles from the capital, Santiago. The most heavily affected area appeared to be the mining port of Iquique near the Peruvian border.
The country's president, Michelle Bachelet, declared parts of Chile's north a disaster zone, promising troops and police reinforcements to maintain order while damage was repaired after landslides blocked roads.Authorities were evaluating the full extent of damage.
Bachelet was scheduled to visit the affected areas later Wednesday.
Over 900,000 people were evacuated from the coastline along Chile. Many still have fresh memories of a deadly February 2010 quake and tsunami that struck the country's central-southern regions fresh in its memory.
An unusually large number of tremors that preceded Tuesday's quake unnerved residents, who emptied beaches, rushed to buy emergency rations, and prepared for an eventual evacuation.
"The government of Chile has been working hard to improve the awareness of people living along the coast to the threat from tsunamis and on what to do if one is approaching," said Steven Godby, an expert in disaster management at Nottingham Trent University in Nottingham, England.
"Several tsunami drills have taken place since the (earthquake and) tsunami that killed an estimated 500 plus Chileans in February 2010, and recent earthquakes in the region have helped to keep the threat firmly in people's minds," he added.
High alertIquique is a key port, close to Chile's main copper mines. The area has been on high alert in recent weeks after an unusual number of tremors, and a series of aftershocks further frayed nerves in the early hours Wednesday.
Seismic Chile has strict tremor-proof construction regulations and most residents stay calm during quakes, which helps to limit harm.
State-owned miner Codelco and other major copper companies reported no harm to workers or mines and said operations in northern Chile were normal. Still, the massive Collahuasi mine evacuated workers so they could be with their families.
History of quakes
Much of Chile's coast borders the oceanic Nazca tectonic plate, which is being pushed under the continental South American plate, creating a geologic hot spot responsible for the creation of the Andes mountains.
That pressure can produce earthquakes greater than magnitude 9, the same class of temblor that caused the 2004 Sumatra and 2011 Japan tsunamis.
Southern Chile produced the most powerful earthquake on record, a magnitude 9.5 temblor in 1960 which killed thousands around the city of Valdivia and brought tsunamis to Hawaii, Japan, the Philippines and the U.S. West Coast. A magnitude 8.8 earthquake in southern Chile killed 524 people and destroyed 220,000 homes in 2010.
Swarms of earthquakes off the northern coast, including a magnitude 6.7 shaker that struck March 16, preceded Tuesday's temblor.
But one earthquake expert who has studied the area warned Tuesday that the quake was unlikely to have relieved the enormous pressures that have built up along the massive fault, which he said had not broken in that area since 1877.
"It's probably not big enough to have released all of the energy that had been stored up along that locked plate boundary for the last 140 years or so," said Rick Allmendinger, a Cornell University professor of Earth and atmospheric sciences. "Is this the big one for that area? Or was it a foreshock to a presumably even bigger earthquake?"
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