Santiago: Chileans` knowledge of earthquakes, combined with the abnormally long time it took for the February 27 quake to reach its crescendo, saved thousands of lives, a leading geophysicist said on Thursday.
Experts have been investigating why Chile`s 8.8-magnitude quake, the world`s fifth strongest recorded earthquake since 1900, killed relatively few people -- around 500, by the government`s estimate.
Walter Mooney, a geophysicist with the U.S. Geological Survey who has been chasing earthquakes in South America for 35 years, credited the Chilean people for knowing to evacuate buildings at the first sign of a big one.
Moreover, the shaking grew over 20 or 30 seconds before reaching its crescendo, he said. Typically that occurs much quicker.
"The combination of the understanding of earthquake risk and the time before the worst shaking and the beginning of collapse -- this saved many, many thousands of lives," Mooney told a news conference at the U.S. embassy.
Even so, many Chileans have harshly criticized the government of former President Michelle Bachelet for issuing late and meek tsunami warnings, an issue that may tarnish her legacy and impede any attempt to run for president again.
Chile`s stringent building codes -- enforced after a 9.5-magnitude quake in 1960 killed 5,000 people and made 2 million homeless -- also helped, Mooney said.
For example this year`s 8.8-magnitude quake was 500 times more powerful than the 7.0-magnitude quake that killed more than 200,000 people in Haiti, a much poorer country that lacked such standards.
Chile is prone to huge quakes because its coast coincides with the unusually long, straight border between the Nazca and South American tectonic plates.
The Nazca plate normally moves 3 inches a year toward the South American plate, but during the February 27 quake it moved 12.5 meters (41 feet), Mooney said.
That triggered three tsunami waves that rose at least 13 feet (4 mts) along Chile`s coastline and surged 26 to 33 feet (8 to 10 mts) in some places.
"The motion of the plate creates the earthquakes, it makes the volcanoes, it makes the Andes and the copper and the beautiful landscape that all Chileans love and the beautiful beaches," Mooney said. "But it comes at a cost."