In the beginning, Iben Browning's sensational forecast was taken seriously. When the iconoclastic scientist cited a good chance that a devastating earthquake will rock the Missouri area about Dec. 3, school districts in three states planned to cancel classes, insurance salesmen were swamped with calls and many people thought about a quick vacation.

Because Browning claims to have predicted the deadly San Francisco Bay Area quake last year, his forecast was given credence and wide attention. But an expert panel reported yesterday that Browning is not all he is cracked up to be.

"The prediction is about as accurate as throwing darts at a calendar," said Robert Wesson, chief of the office of earthquakes, volcanoes and engineering at the U.S. Geological Survey (USGS) in Reston, which assisted an independent panel of 11 quake experts who reviewed Browning's methodology and claims.

Wesson said, at best, there is no more than "a kernel of science" in Browning's methodology, in which he predicts quakes and volcanoes based on the position of the sun and moon and their tide-like influence on the Earth's crust.

Browning, 72, declined to be interviewed for this article. In several forums and in earlier interviews, he has stated that there is a 50 percent chance a quake measuring between 6.5 and 7.5 on the Richter scale will strike along the New Madrid fault about Dec. 3.

The fault, which stretches from southern Arkansas through southeast Missouri to southern Illinois, was the site in 1811-12 of several killer quakes that scientists said would have been measured at 8.0 on the Richter scale, which did not come into use until this century. Last year's Loma Prieta quake in northern California registered 7.1.

Quake experts have said that the New Madrid (pronounced MAD-rid) fault is expected to produce another large temblor but that declaring a date and potential magnitude is irresponsible.

Several major newspapers, including the Wall Street Journal and the New York Times, recently repeated the claim that Browning accurately predicted the Loma Prieta quake a week before it occurred.

"I contacted people who said they heard him say it," said William Robbins of the New York Times, who wrote an article last month on Browning's prediction and the resultant hoopla in the New Madrid area.

The Journal, which published two articles on Browning's prediction, advised its readers not to laugh and stated, "Mr. Browning predicted the Bay Area quake one week before it happened, say people who heard him speak at the time."

Browning did give a speech in San Francisco seven days before the quake struck on Oct. 17, and he did predict a quake for Oct. 16. But, according to taped transcripts of his talk provided to USGS investigators, he never mentioned a location.

Instead, the transcript has Browning saying that, on Oct. 16, "there will probably be several quakes around the world, Richter {scale} 6-plus, and there may be a volcano or two." The panel evaluating his claim said the transcripts did not mention a quake occurring anywhere in California.

Wesson noted that a prediction that does not include a location or a magnitude can hardly be called successful. According to the panel report, about 110 quakes with a magnitude of at least 6.0 occur annually, meaning that one about the size projected by Browning occurs about every three days.

Similarly, the panel said, Browning told an audience in Portland, Ore., May 12, 1980, that an eruption of Mount St. Helens in Washington state was likely "within a week." The volcano erupted six days later.

However, the report said, "Browning's statement was less prescient than it might seem." At the time he spoke, Mount St. Helens had been erupting frequently, its north flank was bulging at a rate of about six feet a day and a large surrounding area had been evacuated and closed to the public.

"A gas station attendant in Portland could have predicted the eruption," said Randall Updike of the USGS and a member of the panel that reviewed Browning's projections.

According to the USGS, Browning also believes that, on or about Dec. 3, the chance is greater than 50 percent that quake-prone Tokyo will be struck by a temblor registering 8.2.

Browning bases his predictions on alignment of moon and sun and their position relative to Earth. When the bodies are aligned, they exert greater pull on the planet that is felt in ocean tides and to a lesser degree in the Earth's crust. According to Browning, this tidal force will be at a 60-year high in early December.

Geologists have spent years trying to find a correlation between "crustal tides" and increased seismic activity. Wesson said scientists have been unable to show a connection.

In a handwritten response to a letter from Wesson seeking information about him, Browning wrote, "As for my credibility, you will find me listed in the 'American Men of Science' and 'Who's Who in America.' "

The "Who's Who" entry states that Browning has a PhD in physiology, genetics and bacteriology from the University of Texas. In it, he describes himself as "a researcher and inventor in the field of optical engineering, information theory, brain physiology, enzymes, climatology and others."

"I guess the bottom line is that Browning is in a win-win situation," Updike said of the New Madrid forecast. "If it happens, he wins. If it doesn't, he still wins. He's a typical predictor."