GEOLOGY : Experts Try to Alter East Coast’s Quake Mind-Set

Buildings shook, people panicked, startled horses reared up in fright when the earthquake hit New York City.

That was 111 years ago.

So it was hardly surprising when one speaker put his finger on the difficult task facing experts gathered here recently.

“The problem of alerting the public to the earthquake hazard is especially challenging for East Coast cities such as New York, where there has been no history of any major damage,” said Howard Kunreuther, a professor of public policy at the University of Pennsylvania’s Wharton School.

“There is likely to be a tendency for residents and businesses in these regions to feel that a severe disaster is practically impossible, so that there is no need to undertake protective measures.”

Acknowledging an uphill battle for attention, earthquake experts from throughout the nation attended a two-day meeting designed to stress the benefits of preparedness for East Coast cities.

Conservative estimates are that a major quake will strike New York City once every 500 years.

In 1886, Charleston, S.C., experienced a serious quake with loss of life. Buildings toppled and locomotives were torn from their tracks when the earth below the surface liquefied.

*

The largest quake to shake New York City was a magnitude 5 in 1884, but the effects were mitigated because the epicenter was offshore in the Atlantic. In 1755, buildings in the Boston area shook from a quake near Cape Ann. Most Eastern Seaboard jolts took place before major population growth and in less densely settled areas, experts said.

“These fortuitous circumstances have lulled the Eastern U.S. population into the misleading perception that earthquakes do not pose a major threat,” said Klaus H. Jacob, senior research scientist in seismology at Columbia University.

Jacob and other speakers at the conference stressed that the powerful January quake that struck Kobe, Japan--killing about 5,400 people, destroying 150,000 houses and about 1,000 large buildings--should serve as a warning for cities like New York.

The effects of an earthquake in New York City could be even greater, speakers predicted. Jacob said seismic shaking during a quake reaches larger distances in the Eastern United States than in the West because of geologic conditions of the Earth’s crust and peculiarities of Eastern rocks and soils.

Many buildings, particularly brownstones, would be especially vulnerable, as would the 2,200 bridges in the New York metropolitan area. Another hazard is soil liquefaction--the process where sandy soil becomes liquid during a quake--toppling structures. Liquefiable soils exist in cities like New York and Boston, which were glaciers 10,000 years ago.

Already, there is some recognition of the problem. Earlier this year, New York City strengthened its building code, adopting some earthquake provisions. The legislation deals primarily with new construction.

“Remember what happened . . . from an explosion at the World Trade Center,” Jacob warned, referring to the 1993 terrorist bombing. “Think of all the buildings having the problem at the same time.”