Quakes Can Be Tough but Vital Teachers

Every earthquake has its own set of lessons. All week long, hundreds of seismologists and earthquake engineers have poured into the Bay Area, looking for clues. They will be months in making the fine distinctions, but the major revelations already are becoming apparent.

Such lessons are crucial because, as we know, Los Angeles will eventually have its own confrontation with the San Andreas Fault. Here’s what we know so far:

* Large earthquakes will make California pay a heavy price for allowing the deterioration of its public infrastructure. The Nimitz Freeway and the Embarcadero Freeway in San Francisco were not upgraded because of the cost. So dozens died, at least, and the price of reconstruction or repair of those structures will dwarf the upgrade costs. The incredible outlays required to rebuild urban freeways are the major reason Gov. George Deukmejian has been forced to consider raising the gasoline tax.

A repetition of those disasters could be avoided in Los Angeles and it will be interesting to see if it happens. Once the hand-wringing over the earthquake ends, once the hundreds of reporters pack up and go home, Caltrans managers will be faced with the same budget squeeze that forced the decision to delay in the Bay Area. One earthquake engineer I talked with made a quick estimate that upgrading the Nimitz alone would have consumed Caltrans’ entire annual allocation of $60 million to $70 million for bringing freeways up to earthquake standards statewide.

And it’s not just freeways. The California Seismic Safety Commission has estimated that one-third of state office buildings may need reinforcement. Virtually nothing has been done.

* The San Francisco event also demonstrated that even though earthquakes themselves are not predictable, the location of severe damage can be predicted with frightening accuracy. It comes down to soil types. The Marina was built on fill; so was the Cypress viaduct on the Nimitz, and the Pacific Mall in Santa Cruz was built on soft, alluvial soils near a riverbed. In L.A., the state already has mapped the neighborhoods with similar soils and that map inevitably will serve as a guide to disaster zones when the large earthquake hits. You can get a copy, incidentally, from the Division of Mines and Geology.

That difference in soil types produces the apparent capriciousness of an earthquake. Just a few blocks from the Marina, century-old Victorians stand without significant damage. The owners of these houses got away unscathed, and the reason is the bedrock under the foundations. This correlation does not work every time, with every earthquake, but exceptions are unusual. If you have to bet, bet on bedrock.

* The disaster here suggests that recovery from a large earthquake may take far longer than generally believed. Marina residents likely will go three months without natural gas, and restoration of the freeway system will take years. Unlike other disasters, an earthquake works underground where things are hardest to fix, and they also attack very large structures that cannot be repaired quickly. Picture an L.A. where the Santa Monica and Hollywood freeways have been rendered unusable for 18 months, or longer.

There is an adjunct to this long recovery time. San Francisco has shown that just finding all the damage is difficult and time-consuming. Only on Friday, three days after the event, did engineers discover that a crucial on-ramp to a peninsula freeway was badly cracked and in danger of failure. This time delay is responsible, in part, for the ever-escalating dollar estimates of total damage.

* Let’s end on some good news. The San Francisco earthquake revealed once again that the modern high-rise can take an extraordinary beating and come out intact. Very few of the new towers in the downtown area suffered significant damage, and in the financial district you would have to search for missing windows. They are proof that we know how to counter the destruction of an earthquake if the money is spent in the right places.

And the disaster here suggested that if you are hurt or trapped by an earthquake, your most likely rescuer will be your neighbor. In that first, dark night of the earthquake, fire departments and rescue squads were overwhelmed, so people saved each other. They crawled into the smoking rubble of buildings or between the squeezed layers of the Nimitz. And these rescues were not isolated events. They took place all over, in great numbers.

Finally, there were the phones. The pay phones never went down and the whole system came back with remarkable speed. It’s as if Pac Bell knows something the rest of us don’t, and that’s fine. I’d rather have phones than heat, any time.