RADON AND THE PROBLEM OF TECTONIC EARTHQUAKES

Abstract

The behavior of radon emanations from rocks was observed in monitoring holes drilled in deep mines. The variation of radon concentration was found to be associated with changes in radon diffusivity controlled by the stress and strain of the rocks. Spatial zoning was found in radon emanation as a function of the distance to a future earthquake epicenter, this spatial variation being obviously nonlinear. Assuming that rockbursts and tectonic earthquakes have the same physical origin, we analyzed the data on the variation of radon concentration obtained in observation wells drilled in the San Andreas fault area. It is shown that the effects observed are similar to those recorded in deep mines. We plotted maps showing the distributions of radon concentrations prior to earthquakes that occurred in 1979-1980. The maps clearly display compression zones associated with the earthquakes, their epicenters being generally located within these zones.