Originally created 01/08/98

Study shows much of coast would flood from asteroid strike



WASHINGTON (AP) - An asteroid three miles in diameter that splashed into the Atlantic Ocean would produce a tidal wave that would wipe out most of the upper East Coast, according to a new study.

Such a disaster is not far-fetched, insists astrophysicist Jack Hills. He heads a Los Alamos National Laboratory research team investigating the risks of tidal waves that could be caused by boulders from space.

Within a 100-year lifetime, Hills said Wednesday, there is a 2 percent to 3 percent chance that an asteroid big enough to trigger coastal flooding will slam into either the Pacific or Atlantic ocean.

In either place, an asteroid could send a 300-foot-tall wall of water racing across the ocean at the speed of a jet plane, Hills said, which would stop only after it smashed into land. As the water retreated, it would scour the land, rip apart buildings, erode vast areas.

The result, he said: disaster.

"The damage would be unprecedented in human history," said Hills, speaking at the national meeting of the American Astronomical Society. "It would kill millions of people and cause billions in damage."

Based on computer simulations of what would happen if an asteroid smashed into the center of the Atlantic, Hills said that all of Delaware, Maryland and Virginia would be inundated. In New York, Long Island and Manhattan would be swamped.

Florida would sustain little damage. Hills said shallow water on a gently sloping continental shelf would protect the Sunshine State. All except Miami, which lies on a deep bay that would suddenly rise up and wash away the city.

Across the Atlantic, the coasts of France, Portugal and part of Spain would be drowned. England, protected by a shallow waters, would be little affected.

A Pacific Ocean asteroid strike midway between Hawaii and San Francisco would launch an ocean wave that would roll over much of Honolulu and flood the Los Angeles basin, dissecting Santa Catalina Island. Across the Pacific, such a wave would wash away coastal cities and towns in Japan, a country that already has lost thousands of lives to tidal waves, or tsunamis, caused by earthquakes.

Based on his studies, Hills estimates that an asteroid more than 600 feet in diameter will strike one of the Earth's oceans at least once every 3,000 to 5,000 years. If a person lives for 100 years, then there is about one chance in 50 of being alive when an asteroid tidal wave occurs, he said.

Hills said geologists have found evidence of such occurrences in the past. The impact of an asteroid several miles in diameter is thought to have helped wipe out the dinosaurs 65 million years ago.

In Hawaii, geologists have found ocean coral deposited on a hillside 90,000 years ago by a tsunami that may have been 1,000 feet high.

Hills said that if an asteroid ocean strike were detected, people would have no more than three hours' warning before the mountain of water traveling hundreds of miles an hour rolled over land.

Astronomical satellites possibly could detect an approaching asteroid, said Hills, but current technology could not prevent Earth from being smashed.