Despite forecast, quake predictions on shaky ground

More than a week ago, a scientist little known in earthquake circles made a bold prediction of a destructive earthquake in the Abruzzo region of central Italy based on spikes in radon gas. Giampaolo Giuliani went so far as to tell the mayor of one of the towns there it would strike within the next 24 hours.

The deadline passed, and for days nothing happened.

Then, early Monday, a magnitude-6.3 earthquake struck near the town of L'Aquila, sparking a controversy around the world about whether Giuliani actually predicted the temblor or whether it was a fluke of timing.

"This happens all the time," said Tom Jordan, director of the Southern California Earthquake Center who is also coordinating a worldwide project called the Collaboratory for Earthquake Predictability. "People send out predictions based on various stuff. It's always hard to evaluate."

The controversy around Giuliani is the latest twist in the maddening scientific quest to predict earthquakes. Over the decades, many ideas have been tested, including studies of cockroach activity along faults, ground warping and the movement of air masses.

"Being able to predict earthquakes is the holy grail of seismology," said California Institute of Technology seismologist Egill Hauksson. "The more we try, the less progress we seem to make."

In 1975, scientists thought the riddle had been solved. Chinese government officials detected foreshocks and successfully evacuated the area of Haicheng before a magnitude 7.3 earthquake. Unfortunately, authorities were not able to predict the Tangshan earthquake a year later and several hundred thousand people died.

Researchers said most of the ideas over the years have been discredited, including the radon-gas theory that Giuliani used when making his quake prediction in Italy.

Soviet scientists appear to have done the pioneering work in the radon field, correlating radon and thoron emissions in well water near Tashkent, Uzbekistan, in the 1960s to an earthquake in 1966. China and Japan also invested in radon research.

Interest in radon as an earthquake signal peaked in the 1970s in California, said Susan Hough, who serves as scientist in charge at the U.S. Geological Survey in Pasadena, Calif., and is writing a book on earthquake prediction. In 1979, for instance, scientists at Caltech and other institutions said they found changes in gas levels in Southern California wells right before quakes in Malibu and Big Bear that year.

"The whole thing deflated when the places where they had detected (radon) had no earthquakes and earthquakes happened in different areas," Hough said.

Giuliani, who lives in L'Aquila and is a technician at a well-respected National Institute of Nuclear Physics, appears to have spoken up about his radon data as early as March 24, in an interview on the Italian blog Donne Democratiche.

"Now there are people who have to apologize to me and who will have on their conscience the weight of what has happened," Giuliani was quoted as saying Monday on the Web site of the newspaper La Repubblica.

Warner Marzocchi, chief scientist at the National Institute of Geophysics and Volcanology, said he first heard about Giuliani's prediction around March 28, when the statements were broadcast on the television and radio.

Residents of the Abruzzo region already were on edge because a swarm of small earthquakes had been rattling the area for weeks, mostly around Sulmona, 30 miles south of L'Aquila, Marzocchi said.

Giuliani told the mayor of Sulmona that a quake would strike between six and 24 hours, Marzocchi said. Some residents of Sulmona evacuated but returned by the time the quake struck near L'Aquila, but there was no major damage in Sulmona, Marzocchi said.