By Duncan Geere, Wired UK
Seismologists hunting for ways to predict earthquakes in advance have stumbled on a potential breakthrough — detecting ozone generated by rocks fracturing deep underground.published in Applied Physics Letters, details how stone breaking apart under pressure releases ozone. The team, led by Raúl A. Baragiola, a professor of engineering physics in the University of Virginia School of Engineering and Applied Science, crushed and drilled into different types of volcanic rock, including granite, basalt, gneiss, rhyolite and quartz. They found that different rocks gave off different quantities of ozone, with rhyolite producing the most.
The team conducted experiments in pure oxygen, nitrogen, helium and carbon dioxide, but found that ozone was only produced when there were oxygen atoms present in the air, in the oxygen and carbon dioxide environments. That suggests that it’s a reaction in the gas that’s producing the ozone, specifically when exoelectrons are emitted by high electric fields, resulting from charge separation during fracture — which is a similar process to the way some materials phosphoresce.
While Baragiola began the study by wondering if animals, which are said to behave oddly just before earthquakes, are detecting changes in ozone concentration, but then realized that ozone detectors might be able to be used as warning devices, bypassing the animal element altogether.
“If future research shows a positive correlation between ground-level ozone near geological faults and earthquakes, an array of interconnected ozone detectors could monitor anomalous patterns when rock fracture induces the release of ozone from underground and surface cracks,” he said, adding: “Such an array, located away from areas with high levels of ground ozone, could be useful for giving early warning to earthquakes.”
He also suggested that an ozone detector array could forewarn of disasters in tunnel excavation, landslides and underground mines.