Scientists say more buildings in East should be quake proof
As researchers gain a better understanding of earthquake hazards east of the Rocky Mountains, they are becoming increasingly concerned about the lack of building-code provisions designed to protect people and property from quakes. ``Except for Massachusetts, very few states in the eastern and central United States have adopted seismic codes for buildings,'' says Klaus Jacob, a senior scientist at Columbia University's Lamont-Doherty Geological Observatory. ``That's like driving without seat belts on.''Skip to next paragraph
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Scientists and engineers point out that while the likelihood of a major quake at any one location in the eastern US is very small, history shows that damaging quakes do occur and can be expected to reoccur. If they do, the economic impact is likely to be more extensive than in the West, owing to high population densities, aged buildings, the large manufacturing base, and geology that on average allows shaking from a quake to cover an area up to 100 times larger than a comparable quake in the West.
For example, Charles Scawthorne, manager of research and development for EQE Engineering Inc. in San Francisco, estimates that an earthquake with a magnitude of six and an epicenter 18 miles southeast of New York's City Hall would inflict some $8 billion in damage on the city. By contrast, last October's Whittier, Calif., quake, with a magnitude of 5.9, inflicted tens of thousands of dollars worth of damage.
Several national building organizations have written model construction codes that contain seismic provisions, but these codes do not have the force of law unless adopted at the state and local level. In adopting the codes, state and local governments can use only the parts they find relevant to them.
A number of states and communities have deliberately excluded earthquake provisions, says MIT civil engineering professor Robert V. Whitman.
Dr. Jacob allows that one reason it's hard to sell the idea of requiring seismic codes for the East is the uncertainty that surrounds an earthquake activity.
``Sometimes we scientists emphasize the uncertainties. That's scientific honesty,'' he says. ``But we have good enough median values to make some fairly confident predictions'' about earthquake conditions. Some researchers say there is a 95 percent chance that a Magnitude 6 quake will occur within 20 years in East.
The unknowns can inject themselves into the debate in other ways. For instance, seismic standards included in the model codes set up by national building organizations are based on data from the West Coast. It's not clear that such standards are applicable to the East.
One of the challenges for seismic code advocates in Memphis has been developing standards more closely tailored to local conditions, says Warner Howe, chairman of the national Building Seismic Safety Council and a Memphis-based structural engineer.
There are also misgivings about the economic impact of designing new buildings, or bringing old buildings, up to seismic standards.
South Carolina, which is now in the process of adopting seismic codes, resisted the move for a long time, says MIT's Dr. Whitman, because engineers and developers were afraid that the cost of implementing them would choke off an economic boom the state was experiencing at the time. Charleston was the site of one of the East's worst recorded quakes. Whitman cites a study indicating that, depending on protection one designs for, increasing a building's earthquake resistance would raise the total cost of a new building by about 1 percent.
Cost becomes a greater factor when considering whether to add strength to existing buildings. If upgrades are made out of the blue, they can be prohibitively expensive, he says. But ``if a bridge is being renovated or old brick warehouses are being turned into developments, at that point you can get things done to increase earthquake resistance at a cost that a person wouldn't even notice.''
Jacob says widespread adoption of seismic codes should take place by 1990. It doesn't matter if, initially, people ``use the cookbook approach'' of adopting model codes, he says. ``Then give us 10 years' time to do it right.''