Seismologists are on edge, too. Last week’s temblors, about three hours apart and measuring 7.4 and 6.5 on the Richter scale, occurred on two different fault lines in the area of Palm Springs, about 40 miles southeast of Los Angeles. One fault runs north through Yucca Valley. The other runs northeast near Big Bear Lake, a popular vacation spot. These faults seem to form two legs of a triangle with a segment of the notorious San Andreas Fault. It is thought that the southern stretch of the fault has been " locked" by a bend in this segment for more than 300 years, keeping the tectonic plates on both sides from moving. But last week’s quakes may be a sign that this segment is ready to break loose. “I am concerned,” said Tom Henyey, executive director of the Southern California Earthquake Center. " In fact, my concern level is the highest it has ever been for a major earthquake in southern California in the near future. I think we’re getting closer and closer to the Big One."
But last week’s quakes could have qualified as Big Ones if they had occurred closer to L.A.’s urban sprawl. Ripping along at a speed of two miles per second, these tremors could have shattered freeways, pipelines, electrical lines and buildings in the greater Los Angeles area. Power stations, water plants and sewage-treatment plants would have shut down. Major fires would have been inevitable, and firefighters in many cases would have had no water to fight them. According to surveys taken in the early 1980s by federal experts, the death toll in an 8.3 quake on the San Andreas Fault near L.A. could run as high as 14,000-though in truth, no one can say whether that projection is remotely accurate. Some 55,000 people might require hospitalization, and as many as 141,000 people would be homeless.
And even a lesser quake could cause unimaginable destruction. State officials say a 7.0 quake on the Newport-Inglewood Fault or the Elysian Park-Santa Monica Fault could produce one of the nation’s greatest natural disasters. The Newport-Inglewood Fault runs from Beverly Hills southwest to Newport Beach and offshore–a highly populated, heavily industrialized swath of Los Angeles County about 25 miles long. Death-toll estimates for a quake in this area range up to 20,000, and 10 times as many people could be homeless. The city of Long Beach, a major industrial center, could be turned into an inferno as oil refineries there explode in flames. Scientists say the Elysian Park-Santa Monica Fault could be even deadlier since it would directly hit downtown L.A.
Now for the good news. The Big One could just as easily rip up thousands of square miles of vacant desert land and leave L.A. and its suburbs largely unscathed. It all depends “on where it is,” says Dave Perkins of the National Earthquake Information Center. “A big quake can sit out there and not do any damage at all.” So while last week’s quakes suggest Angelenos are playing seismic Russian roulette, even the experts can’t say which way the gun is pointing–or when it will go off.
When the Earth Moves: Three Deadly Quakes Mexico City Sept.19-21,1985 8.1 magnitude 4,200 deaths $3 to $4 billion in property damage San Francisco Oct. 17,1989 6.9 magnitude 62 deaths $6 billion in property damage Northwestern Iran June 21,1990 7.7 magnitude 40,000 deaths $600 million in property damage*
*ESTIMATE FROM THE WORLD BANK. SOURCE: U.S. GEOLOGICAL SURVEY
