Editing Earthquake prediction (section)

==== Radon emissions ====
Most rock contains small amounts of gases that can be isotopically distinguished from the normal atmospheric gases. There are reports of spikes in the concentrations of such gases prior to a major earthquake; this has been attributed to release due to pre-seismic stress or fracturing of the rock. One of these gases is [[radon]], produced by radioactive decay of the trace amounts of uranium present in most rock.<ref>{{Harvnb|ICEF|2011|p=333}}.</ref> Radon is potentially useful as an earthquake predictor because it is radioactive and thus easily detected,{{efn|1=Giampaolo Giuiliani's claimed prediction of the [[#L'Aquila|L'Aquila]] earthquake was based on monitoring of radon levels.}} and its short [[half-life]] (3.8 days) makes radon levels sensitive to short-term fluctuations.

A 2009 compilation<ref>{{Harvnb|Cicerone|Ebel|Britton|2009|p=382}}.</ref> listed 125 reports of changes in radon emissions prior to 86 earthquakes since 1966. The International Commission on Earthquake Forecasting for Civil Protection (ICEF) however found in its 2011 critical review that the earthquakes with which these changes are supposedly linked were up to a thousand kilometers away, months later, and at all magnitudes. In some cases the anomalies were observed at a distant site, but not at closer sites. The ICEF found "no significant correlation".<ref>{{Harvnb|ICEF|2011|p=334}}; {{Harvnb|Hough|2010b|pp=93–95}}.</ref>