Costa Rica escapes relatively unscathed after 7.6 earthquake
September 7, 2012, 12:08 am TWN
CANGREJAL, Costa Rica -- The bulletins were terrifying: a powerful earthquake had struck off the coast of this Central American country, spawning a tsunami warning and bringing fears of widespread catastrophe.
But Costa Rica suffered remarkably little damage from Wednesday's magnitude-7.6 quake — a few blocked highways, some collapsed houses and one death, of a heart attack caused by fright. Officials credited the relatively deep location of the quake and building codes that Costa Rican officials call as strict as those in California and Japan.
The quake was 25 miles (41 kilometers) below the surface. Tremors that occur deep underground tend to be less damaging, but their shaking can be felt over a wider area.
“If it was a shallower event, it would be a significantly higher hazard,” said seismologist Daniel McNamara of the U.S. Geological Survey.
The U.S. Geological Survey said the quake was centered about 38 miles (60 kilometers) from the town of Liberia and 87 miles (140 kilometers) west of the capital, San Jose.
The area is a seismically active zone where the Cocos tectonic plate dives beneath the Caribbean plate. “All along the Pacific coast of Central America, you can expect fairly big earthquakes,” McNamara said.
The quake was followed by three strong aftershocks of magnitudes above 4.
The relatively little damage was due in large part to strict building codes in Costa Rica, a country that has long enjoyed more stability, better governance and stronger economic development than many of its Central American neighbors, said Olman Vargas, president of the national College of Architecture and Engineering.
“We have a culture of concrete and steel,” he told The Associated Press. “Years ago we abandoned building in mud and adobe, something that's caused a lot of problems and that they're continuing in other countries.”
Costa Rica's anti-earthquake structural codes have been updated in line with the latest international standards three times since they were enacted in 1974, most recently last year.
“I can assure you we comply with all global standards — the same as in California and Japan, places well-known for their high tectonic activity,” Vargas said.
Officials said the quake collapsed some houses and at least one bridge and caused landslides that blocked highways. But Costa Rica President Laura Chinchilla said there were no reports of major damage.
Residents described being shocked by the force of the quake, which was felt as far away as Panama and Nicaragua and was the biggest since a 7.6-magnitude quake in 1991 that killed 47 people.
Officials initially warned of a possible tsunami. Samara local police supervisor Jose Angel Gomez said about 5,000 people had been evacuated from coastal towns in and near the quake's epicenter, but they were allowed to return by midday.
One death was confirmed, a man who died of a heart attack caused by fright, said Carlos Miranda, a Red Cross worker in the city of Liberia.