Word: seismic
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Dates: during 1980-1989
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...scientists, the great quake and its aftershocks were not surprising. Karen McNally, a geophysicist at the University of California, Santa Cruz, had warned in 1981 that substantial seismic activity was likely in the area. "Everything we had seen," she says, "could not allow us to exclude the possibility of a major earthquake...
...seeming paradox, the location of last week's quake was thought to be endangered because it had been calm for so long. The epicenter of the quake, in the ocean about 150 miles up the coast from Acapulco, lay within a kind of geological DMZ known as a seismic gap: a region that had not experienced a major earthquake for many years, but where bottled-up stress caused by tectonic-plate activity had reached the bursting point...
...kind of seismic party line, one earthquake may signal that another could occur; sites that lie between past gaps hit by recent tremors are the areas most likely to rupture next, rather the way buttons popping on a shirt put greater pressure on the buttons still intact. Noting that earthquakes in the 20th century have periodically shaken surrounding regions, geologists knew that Mexico's Michoacan gap--quiescent for many decades--could not hold out forever. "Wherever stress builds up for a long time in a seismic gap," says David Simpson of Columbia University's Lamont-Doherty Geological Observatory, "something...
...Zihuatanejo and Ixtapa, only 50 miles from the epicenter, suffered less damage than Mexico City, 200 miles away. That is because the shoreline is made of solid rock and thus shakes less violently. Mexico's capital, however, was built on an alluvial lake bed. As a result, the seismic waves, though diminished in intensity on their trip from the coast, were amplified in the city's sediment foundation. Many tall buildings in the densely populated metropolis may not have been built to rigid quake- resistant standards. Indeed, some turned out to be just the right height to vibrate or resonate...
...official explained that the company offers businesses storage for data backup against the threat of disaster. "Earthquakes, fires, these things are very positive for us." Saboteurs are also positive peddling points, he said, as well as employee drug addicts selling information for dope. He spoke proudly of "seismic bracing" in the company's storage vaults...