Learning from disaster

American engineers were among those who examined the recent earthquake damage in Turkey and Taiwan to determine what survived, what did not - and why. Their discoveries may enable engineers to better buttress built environments against temblors of comparable magnitude. The effort was mounted in accordance with the National Earthquake Hazards Reduction Program Reauthorization Act of 1990, which mandates the multidisciplinary study of domestic and foreign earthquakes. The strong ground shaking produced by the Turkish earthquake was not unusually high, reaching around 40% of the acceleration of gravity in the epicentral region, but the quake was of long duration - 45 seconds - so the shaking was a significant factor in the degree of structural damage sustained. The most vulnerable buildings were multistory commercial and residential structures 3 to 8 stories in height built of reinforced concrete with unreinforced masonry infill walls. The fundamental lesson to be embraced by all nations is that the design technologies that mitigate damage from seismic events must be understood and applied by those responsible for the built environment.