By studying caves for traces of ancient seismic activity, French geologist Eric Gilli developed a new method to predict earthquakes.
Earthquake forecasting is a challenge in natural hazard prediction. Scientists look at movement of plates in the Earth and the location of fault zones. They also make calculations based on where and when previous ones occurred. But what if there is no record of tremors in a region?
Caves are very good recorders of natural phenomena. In the same way that the underground environment has preserved prehistoric human records – paintings, bones, tools – for thousands of years, they have also preserved traces of many earth movements.
Caves can give us information we could never find any other way. Eric Gilli, a passionate speleologist and pioneer in this field since 1980, came up with the idea of searching for traces of earthquakes or fault-line movements in caves and caverns. For example, stalactites and stalagmites that no longer face each other indicate the roof has shifted. Through radioisotope dating, geologists can reconstruct cave movements to indicate earthquakes dating back thousands of years.
“We hope it will allow us to put forward a method for evaluating the risk of earthquakes in a large number of regions where there is no historical data,” said Gilli, whose Rolex Award allowed him to collect data in areas of high seismic activity and present his method to geologists in other countries.
He made field trips in several countries, resulting in a book published in 2011. Now a professor of remote sensing, geomorphology and geology at the University Paris 8, he has written 130 scientific papers and five books on cave studies and their applications. He has also travelled to Sarawak in Malaysia to photograph the world’s biggest underground chamber.
Years of earthquake data that Gilli’s method of cave exploration has the potential to reveal