Designing Earthquake-Proof Buildings

Feb. 28 -- After every earthquake, engineers rush in to study why buildings crack and crumble and what can be done to make structures safer.

At the University of California at San Diego, scientists are recreating the force of the 1994 Northridge, Calif. earthquake that killed dozens and caused considerable damage to wood-framed buildings and $2.5 billion of damage overall. What they learn will help them improve building codes.

The reason some earthquakes are so deadly is clearly a matter of magnitude. The recent quake in India registered 7.9 on the Richter scale, 10 times the force of today's temblor in the Pacific Northwest. But the construction of the buildings there is what proved to be so fatal, as most unreinforced masonry crumbled under the strength of the quake, causing the deaths of more than 14,000 people.

And experts say that in Seattle, a bigger quake than today's could wreak real havoc.

Most of the buildings in Seattle and its environs are not earthquake proof. Old homes are often made of brick, said Tom Yellin, a USGS seismologist at the University of Washington in Seattle.

"A lot of the houses are of made of brick, with no reinforced steel bars," he said.

In addition, older establishments' buildings were not attached to their foundations, making them more susceptible to earthquake damage.

Experts say buildings can be made to survive earthquakes intact.

"It is actually easier to build a home to withstand an earthquake because the loads generated by an earthquake are about half of what is created by a hurricane or a tornado," explains Donald Pearman, a construction earthquake and fire expert.

Scientists Develop Stronger, More Flexible Material

Scientists are developing smart materials, including fiber-optic sensors that can sense when a structure is about to give way. And tiny ceramic strips that change shape when electricity is passed through them to help buildings flex.

And at Notre Dame University, they've developed sensors to both detect the earthquake force and the movement of the building. Dampers, which act like shock absorbers, kick in and let the building ride out the quake.