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NGM MAPS. Source: Global Seismi Hazard Assessment Program. Not all islands shown.

Blondet has been working on ideas since 1970, when an earthquake in Peru killed 70,000 or more, many of whom died when their houses crumbled around them. Heavy, brittle walls of traditional adobe—cheap, sun-dried brick—cracked instantly when the ground started bucking. Subsequent shakes brought roofs thundering down. Blondet's research team has found that existing adobe walls can be reinforced with a strong plastic mesh installed under plaster; in a quake, those walls crack but don't collapse, allowing occupants to escape. "You rebuild your house, but you don't bury anyone,” Blondet says. Plastic mesh could also work as a reinforcement for concrete walls in Haiti and elsewhere.

Other engineers are working on methods that use local materials. Researchers in India have successfully tested a concrete house reinforced with bamboo. A model house for Indonesia rests on ground-motion dampers designed by John van de Lindt of Colorado State University: old tires filled with bags of sand. Such a house might be only a third as strong as one built on more sophisticated shock absorbers, but it would also cost much less—and so be more likely to get built in Indonesia. "As an engineer you ask, What level of safety do I need?” van de Lindt says. “Then you look at what’s actually available and find the solution somewhere in between."

In northern Pakistan, straw is available. Traditional houses are built of stone and mud, but straw is far more resilient, says California engineer Darcey Donovan, and warmer in winter to boot. Donovan and her colleagues started building straw-bale houses in Pakistan after the 2005 earthquake; so far they have completed 17.

The same stark contrast prevails in other fault zones: encouraging ideas, discouraging progress. Even cheap ideas aren't always cheap enough. Since 2007 some 2,500 houses in Peru have been strengthened with plastic mesh or other reinforcements, with another 700 scheduled for this year. That leaves millions of houses and billions of dollars to go in Peru alone, to say nothing of other countries. “There are many millions of houses around the world,” Blondet says, "that will collapse in the next earthquake." — Chris Carroll

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