THE largest earthquake to hit the San Francisco area since 1906 is a devastating reminder of the impact a major quake can have when it strikes an urban area. It will test the nation's emergency response capability, already strained from the damage caused by hurricane Hugo. It is also likely to bring calls for greater earthquake readiness in a state that may already be the best equipped to handle such a disaster.
Although apparently not the big one many Californians have long anticipated, the 6.9 magnitude quake that hit at 5:04 p.m. Tuesday is one of the most severe in California - indeed, the nation's - history.
Centered along the San Andreas fault, about 8 miles northeast of Santa Cruz and 75 miles south of San Francisco along the San Andreas fault, the temblor was reported early Wednesday to have killed 271 people, according to Lt. Gov. Leo McCarthy. Hundreds of injuries were reported in the Bay area with some injured when a 30-foot section of the San Francisco-Oakland Bay Bridge, was severed.
The quake delivered a particularly devastating blow, coming as it did at rush hour. Most of the deaths occurred when a half-mile-long upper level section of Interstate 880 in Oakland collapsed onto the lower level, crushing dozens of vehicles and killing 253, according to the state Office of Emergency Services. The agency said 400 people were injured in the highway collapse.
The earthquake also forced evacuation of 60,000 fans from Candlestick Park where they were awaiting Game Three of the World Series. There were no major injuries at the stadium.
Hundreds of people fled Bay Area Rapid Transit subway and elevated stations in San Francisco and East Bay suburbs. The system was shut down. Oakland Airport was closed, with only outgoing flights at San Francisco Airport.
Damage to property and infrastructure is expected to reach into the hundreds of millions of dollars - from jostled computers in Silicon Valley to buckled bridges.
In San Francisco, the destruction was severe in old neighborhoods near the marina, where the wriggling earth turned brick buildings into tombs of rubble. In San Jose, to the south, where the destruction was less catastrophic, at least a dozen buildings were damaged. A shopping mall in Santa Cruz, the city closest to the epicenter, partly collapsed.
Throughout the area, roads buckled, some bridges fell, utility lines ruptured, and power and phone lines went out for at least a million residents, utility officials said. At least two bridges in the Santa Cruz area collapsed and other highways leading out of the city suffered significant damage, according to the California Highway Patrol. Mountain passes were closed on Wednesday because of major landslides and fissures.
Fires - a culprit that helped destroy much of San Francisco after the 1906 earthquake - broke out in several cities, though crews quickly responded.
Military personnel were dispatched to patrol the streets in San Francisco, where some looting was reported Tuesday night. Mayors in the area have declared states of emergency. Federal officials, including Secretary of Transportation Samuel Skinner, are surveying the damage. Schools throughout the region are closed.
Although the devastation was largely limited to San Francisco, Oakland, and cities and counties immediately to the south, the earthquake was felt as far east as Reno, Nev., and as far south as Los Angeles. It was the sixth strongest earthquake in California this century. Although smaller than the great 1906 quake, it was substantially bigger than the one that struck Whittier, Calif., in 1987, causing more than $200 million in damage.
Devastating as it was, the temblor could have been worse. Seismologists note that if the center of the quake had been closer to San Francisco, where the underlying geology carries waves like a tuning fork, instead of along the slip-fault in the rumpled hills near Santa Cruz, the damage would have been more severe.
Modern earthquake engineering - of which California has some of the world's most sophisticated - also helped cushion the impact. The recent earthquake in Soviet Armenia, where thousands perished, was about the same size as the one here, though the geology in the area was far different.
``This was only slightly smaller than the one in Soviet Armenia, which shows how our building requirements have been helping us,'' says Dr. Kate Hutton, a seismic analyst at the California Institute of Technology (Caltech).
After being briefed on the initial extent of the damage, California Gov. George Deukmejian, who was in Europe at the time the temblor hit, expressed ``surprise'' at the number of bridges and roads that had crumpled. He said he thought they were ``made to withstand a shock of this magnitude.''
The quake felt ``like a very sudden, sidewise pull,'' said Hank Henson, a Berkeley resident, ``like the old trick of somebody yanking a tablecloth off a table without disturbing the dishes on it.'' Mr. Henson, walking along a Berkeley sidewalk when the quake hit, kept walking to see how the city had fared. He found ``isolated catastrophic incidents,'' such as an occasional collapsed building, and ``only one big Berkeley fire that I could see.''
Wooden-framed homes that had been braced fared better than older, unbraced buildings, Henson said. ``Around here they run long bolts through the sills into the concrete,'' he added: ``It's not a major thing to do,'' Henson said, ``but it has a major effect'' in stabilizing buildings.
While other benumbed Bay area residents begin their cleanup, they will be anxiously watching the richter scale needle. Characteristically after a quake of this size, dozens of aftershocks follow, some of them large.
``There will be plenty of fives and maybe a six or two and the aftershocks will be felt for months,'' says Kathy Watts, a Caltech seismic analyst.