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A device that can detect gas being squeezed out of rocks could become the first reliable method for predicting earthquakes, according to its developers, who are about to test the device for the first time.
Scientists suspect that radon gas is released from cavities and cracks in rocks into soil and groundwater before an earthquake strikes. But commercially available detectors are too expensive to test this theory in a wide scale trial.
Now, Mexican and European scientists have developed a prototype of a simple detector cheap enough to use in large tests.
Vladimir Peskov, a member of the design team and a physicist at the National Autonomous University of Mexico, said they aim to use a network of the cheaper detectors to test the theory that radon is released as layers of rock around a strained fault line deform before a sudden quake-causing slip.
The device is based on a technology that is already used in extreme environments such as the CERN particle physics laboratory near Geneva, Switzerland.
It consists of a 20-centimetre long, nine-centimetre wide aluminium tube which contains a number of wires along its length connected at either end to electrodes. When radon gas enters the tube it strips air molecules of electrons, triggering an electric current in the wire. Unlike existing detectors it works in ambient air.
The design was presented at the Vienna Conference on Instrumentation in early 2010 with a paper that showed its performance to be similar to commercially available devices deposited in arXiv, and a related paper is in press in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
"This is an impressive breakthrough," said Heikki Sipilä, an industrial engineer who has been developing gas detectors since the 1960s, and was not involved in the research.
"The detectors are simple and production costs low because no filling gas or expensive materials are needed," he told SciDev.Net.
Peskov told SciDev.Net that each detector will cost an estimated €50-100 (US$66-132) to produce. His team is planning to test several devices in the Bari region of Italy, which experiences frequent "micro earthquakes".
Tom Hockaday, managing director of ISIS Innovation, a UK technology transfer company, said that the devastating 2010 Chile and Haiti earthquakes had highlighted the dearth of technologies across the spectrum — from predicting quakes to helping with aid efforts.
Although this detector sounds promising and relatively straightforward, he said, full implementation would require fitting each detector with a radio transmitter to broadcast a signal, which might complicate its rollout in developing countries.
"There are challenges in deploying highly complex technologies in areas with relatively undeveloped infrastructure," said Hockaday, adding that it could be difficult to convince companies to invest in such early-stage technologies.
However, the inventors are optimistic and are seeking for collaborators from around the world to test the device. The long-term goal is to conduct full-scale testing along a number of fault zones with international backing, they told SciDev.Net.
If the device is proven reliable in upcoming field trials then they may be of particular interest to developing nations where the human impacts of earthquakes and related tsunamis are often at their most devastating.
Link to full paper in arXiv [472kB]