EarthquakesJapan questions earthquake forecasts

Published 2 March 2012

Following the massive 11 March earthquake and tsunami that rocked Japan, residents and experts there have grown increasingly skeptical of quake forecasts

Following the massive 11 March earthquake and tsunami that rocked Japan, residents and experts there have grown increasingly skeptical of quake forecasts.

Last month two University of Tokyo seismologists released a study that predicted a major earthquake would hit Japan’s capital city within the next four years. Their study was sharply criticized by those who said their claims were likely incorrect.

Bowing to pressure, the university’s Earthquake Research Institute posted a notice on its site that stated the latest earthquake forecast was the opinion of two researchers and noted the study’s “large margin of error.”

“Many seismologists think this kind of study is too simple,” said Naoyuki Kato, a seismologist at the institute, in an interview with the Washington Post.

Japan, which has been frequently rocked by powerful earthquakes in the past, invests more money than any other nation in the world on earthquake prediction, yet despite spending more than $100 million annually, the art of predicting earthquakes remains elusive.

The Japanese are not alone in their skepticism of earthquake prediction techniques, as most experts around the world believe it is not possible. But that skepticism has not stopped Japanese researchers, funded by the government, to pursue everything from studying historical data, digging through fault lines, smashing rocks in laboratories, and attaching instruments to the sea floor in the hopes of unlocking the mystery of earthquakes.

“The problem is, people are getting lots of money for predictions,” explained Robert Geller, a professor of geophysics at the University of Tokyo. “So it’s like an arms race to exaggerate the practical benefits of one’s own research.”

In defense of their work, Shin-ichi Sakai and Naoshi Hirata, the authors of last month’s earthquake report said they had noticed a sharp increase in the number of minor earthquakes in and around Tokyo following the 11 March tremor.

Figuring that the 11 March quake may have shifted the plates near Tokyo, Sakai thought the small earthquakes were an indication of something larger. Using the Gutenberg-Richter law, which describes the correlation between small quakes and large ones, the two researchers arrived at their conclusion that a major quake would strike Tokyo in the next several years.

“The purpose of our study was not really to make a forecast. It was to show that seismic activity has intensified,” Sakai told the Post.

Admitting that earthquakes are nearly impossible to predict, Sakai said, “So why do we have all these new earthquakes in an area so far away from the [11 March] epicenter? It could be random. There is no way to resolve whether our forecast is accurate.”