Saturday, May 28, 2011

Better Prediction Sought for Devastating Floods

It fiercely shook the capital Lima, but its devastating epicentre was about 200km (124 miles) to the south, near the town of Pisco, a small fishing port built largely of adobe - mud bricks which Peruvians have used for thousands of years.

More than 500 people were killed and about 75,000 homes were left uninhabitable.

For Peruvian engineer Marcial Blondet, it was the devastating quake in 1970 that first motivated him to develop earthquake-resistant buildings, particularly for those who could least afford them.

Some 70,000 people died in the mountainous region of Huaraz, many of them in an avalanche of snow, ice and rock which obliterated the town of Yungay. It was the deadliest earthquake in Latin American history.

'Tragic combination'

"Adobe and earthquakes are a perverse and tragic combination," says Mr Blondet.

"We are right in the middle of the most seismic area in the world. We've had many, many huge quakes and we are still waiting for the super big one.

"But a very large percentage of the people here are poor, so adobe is the only thing they can use to build their homes. Unfortunately, that's the case for millions of people in seismic zones around the world."

During more than 35 years of research, Mr Blondet and his team have tried a range of natural and industrial materials to try to reinforce weak mud-brick structures. Bamboo cane was one option, but there is not enough of it.

Mud-brick structures are tested vigorously on shaking tables which simulate earthquakes in the structural engineering laboratory at Lima's Catholic University.

Watching the simulations, it is easy to see just why adobe houses, home to about 40% of Peruvians, are such death-traps.

First a vertical crack appears, then the outer wall falls outwards, before the other walls crumble and the roof caves in.

"The people on the street are killed by the walls that fall out, the people inside are killed by the roof that falls in. It's terrible," says Mr Blondet.

"No-one should live in a house that behaves like this. A house is a place where we go when we want to feel protected and safe, so it's unbearable, completely unacceptable - an abomination - that your house kills you."

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