State of fear

摘要

Easels holding seismic maps of Italy are standing all around the western headquarters of the United States Geological Survey in Menlo Park, California. Given that Californians live in permanent fear of "the big one", they feel "lots of scientific and emotional connections" to Italy's recent earthquake, which killed 294 people and destroyed ancient towns, says Ross Stein, a scientist there.rnAmerica's entire western coast sits on or near tectonic faults. Since these forces formed the coast's harbours, and since people have settled largely around thosernharbours, the populations tend to be where the risks are highest.rnIn California, which has about 1,500 known faults, two are particularly menacing. One is the southern San Andreas, where the Pacific plate shears north-west along the North American plate, and where a "swarm" of tremors under a desert lake near the Mexican border has recently caused worry about a bigger quake being triggered near Los Angeles.