Word: seismicity
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Dates: during 1990-1999
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...such signals preceded Mount St. Helens' 1980 blast. They also appeared before the unexpected explosion of Mexico's El Chichon in 1982, the blowup of Colombia's Nevado del Ruiz in 1985 and 1987 and multiple eruptions of Alaska's Redoubt. Seismometers positioned at Pinatubo have recorded similar seismic patterns...
...Loma Prieta quake, says geophysicist Peter Ward of the U.S. Geological Survey, "might be viewed as a warning shot. We may be headed into a period of much higher seismic activity." Last July the USGS issued a "probabilities report" estimating a 1-in-3 chance that another quake equal in strength to Loma Prieta could strike the Bay Area. At a conference of 1,000 earthquake experts who are convening this week to mark the anniversary, participants will be reminded that a 7.5 quake is expected at some indeterminate future date along the Hayward fault, which runs through a more...
...sleepy cotton fields around New Madrid, Mo. (pop. 3,400), convey no sense of seismic menace. Yet scientists say the area is potentially one of the most dangerous earthquake zones in the world. Early in the past century an unseen fault, obscured by tons of sediment, unleashed a fearsome trio of tremors -- each as powerful, some say, as the earthquake that virtually destroyed San Francisco in 1906. The eyewitness accounts read like the tall tales of Baron Munchhausen. The ground rippled with waves as though it were an ocean. The Mississippi River raged with waterfalls and rapids. Fountains of sand...
...line between the North American and Pacific plates, which are slowly slipping past each other. But the New Madrid fault lies in the middle of the North American plate, seemingly far from harm's way. Why do earthquakes occur in such an out- of-the-way spot? By analyzing seismic data, scientists have concluded that the New Madrid fault is a failed rift, or break, in the North American plate. Had it progressed further, the embryonic gap might have created a body of water like the Red Sea, which is slowly widening into an ocean. But hundreds of millions...
...they slept. Aftershocks rippled through the area in the next 36 hours, including one that registered 6.5 on the Richter scale. Iran's Red Crescent Society indicated that at least 400,000 people in a region of 3.7 million had been left homeless. The country's location between two seismic zones has rendered it vulnerable to earthquakes. In 1968 one tremor killed 18,000 people. Ten years later, another killed...