Seattle's soft spot boosts power of quakes

摘要

Seattle enjoys a buzzing reputation for its coffee culture, but the city faces the threat of a caffeine-free jolt in the future. Seismologists this week report that the thick foundation of sediments underlying Seattle is less rigid than previously thought and will amplify shaking during earthquakes. Much of the new information about the city's seismic risk comes from a large project launched in March 1998 to explore the hidden geologic structure of the region surrounding Seattle and Vancouver, British Columbia. The $3 million effort sent ships with airguns throughout Puget Sound and connecting waterways, where they fired 33,000 volleys of sound through the water and into Earth's crust.