Big Earthquake Said Overdue in Asia... THE HOWARD CHRONICLES 082401

AUGUST 24, 02:27 EDT
<B>Big Earthquake Said Overdue in Asia </B><I>

By PAUL RECER
AP Science Writer </I>

WASHINGTON (AP) — Seismic stresses building up near the Himalayan Mountains could break free and cause a massive earthquake of eight or more magnitude in the near future, according to a new study.

Researchers report Friday in the journal Science that such an earthquake would put more then 50 million people at risk and threaten large cities in India, Nepal, Pakistan, Bangladesh and Bhutan.

Roger Bilham of the University of Colorado, Boulder, lead author of the study said that at least one earthquake of 8.1 to 8.3 magnitude is overdue along the 1,250-mile seismically active front of the Himalayas. Bilham said he and his co-authors searched for evidence that seismic strain building up along the mountains has been relieved by earthquakes in recent centuries.

``Unfortunately, we have been forced to reach a very undesirable conclusion,'' Bilham said. ``We set out to try and eliminate the possibility of one or more large, overdue earthquakes in the Himalayan occurring very soon, and we have failed.''

He said his group could not precisely predict when a massive earthquake would occur, but that it could be ``very soon'' in geologic terms. A massive earthquake must occur to relieve the seismic strain that builds up along the contact points of two shifting plates and no such earthquake has hit that area in hundreds of years.

Bilham said the geologic plate carrying India is slowly slipping under the Asian plate. This is what caused the rise of the Himalayan Mountains and is the source of great seismic strain along the mountain range.

He said this increasing strain has put about two-thirds of the 1,250-mile mountain front in ``a perilous condition.'' He said some small earthquakes in the last 200 years have relieved some of the seismic strain along about a third of the front.

Bilham said that about 50 million people live in the areas at risk of a massive earthquake and many live in buildings that offer little resistance to collapse from earthquake action.

In 1905, an earthquake struck Kangra, an Indian town, and caused about 19,000 deaths. If a similar earthquake hit the same town now, he said, the death toll could be 200,000 or more because of the increase in population.

Bilham said the Indian plate is slipping under the Asian plate at about the rate of about six feet a century along the entire front. This amounts to an area the size of about 10 soccer fields a year moving under the Asian plate.

The strain that results from such movement is like a spring being pulled tighter and tighter, he said.

``We know the inevitable outcome,'' said Bilham. ``The lock holding the spring will break. ... A giant earthquake is the only solution to have these plates unzip and slide.''

He said there have been no great earthquakes in the area for about 500 years, but geologic evidence shows that they have happened in the past.

Robert L. Wesson of the U.S. Geologic Survey said the findings by Bilham and his co-authors are ``absolutely consistent with the current view of what is going on there (in the Himalayan area).''

He agreed that a massive earthquake in the area could cause thousands of casualties.

``The population there has soared and the construction practices are suspect,'' said Wesson. ``The combination means that when we have one (massive earthquake), we could have a really bad situation.''

Most earthquake deaths result from the collapse of buildings, trapping victims under brick, steel and wood.

Wesson said that despite extensive study, experts still can't precisely predict when earthquakes will occur, ``but we know they will happen. It could be tomorrow, the next day or perhaps the next century.''

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