Predicting earthquakesThe debate over radon as an earthquake predictor continues

Published 30 November 2012

Scientists have been interested in using radon emissions to predict earthquakes since the 1980s, but no solid evidence ever came to support it and the idea was abandoned by most in the field during the 1990s; now, scientists are looking again at radon as an earthquake predictor

Giampaolo Giuliani predicted the large earthquake that hit L’Aquila, Italy in 2009, killing 297 people and injuring hundreds more, and leaving tens of thousands homeless. Giuliani, a researcher at the Gran Sasso particle physics laboratory, based his prediction on the rising levels of radon that his instruments had picked up.

Radon is a radioactive gas produced by the natural decay of uranium. It can build up in cavities and cracks, and it is believed that the earth’s crust can release bottled-up radon before an earthquake.
When Giuliani alerted the authorities, they responded by warning residents to evacuate their homes. When the Earthquake failed to strike, city officials became upset with Giuliani and forced him to take down warnings that he posted online.

The International Business Times reports that in the past Giuliani attempted to get funding to study ways techniques for predicting earthquakes by studying radon emissions but was turned down.

Other scientists and geophysicists in the field do not believe that there is a connection between radon emission and earthquakes. Ross Stein of the U.S. Geological Survey (USGS) told the New York Times in 2009 that scientists have been interested in using radon to predict earthquakes since the 1980s, but that no solid evidence ever came to support it and the idea was abandoned by most in the field during the 1990s.

According to Ross, one issue with using radon to predict earthquakes is that many scientists measure the Earth’s surface to predict an earthquake, but the events that lead up to an actual earthquake happens miles underground. Most geologists agree that no single indicator has ever proven reliable in predicting an earthquake, and even Giuliani’s prediction was off by more than a week.

In December 2011 Chapman University geophysicist Dmitar Ouzounov presented work relating to a 5.8 magnitude earthquake in Virginia. Ouzounov and his team researched seven years of satellite images of the earthquake site and estimated the average heat radiating at site each day.

The results showed that thermal radiation spiked significantly about two weeks before the quake and on the day of the quake. Some scientists think the heat and electrical changes before the earthquake were caused by radon gas escaping and heating the lower portions of the atmosphere.

USGS researcher Malcolm Johnston said last year that he was still skeptical about the idea. Johnston tried to prove radon could predict earthquakes, but could not find a connection despite measuring twenty years of radon levels in California.

According to Johnston, natural weather fluctuations could be accountable for the spikes in heat over Virginia at the time of the quake. “That’s the biggest noise source, and a crucial correction that needs to be done,” Johnston told the International Business Times.