Determination of the dilatant inclusion boundaries according to the results of the radon anomalies interpretation

For the correct interpretation of radon exhalation data for the study of tectonic processes in the earth’s crust, in particular earthquakes, three main components are necessary. 1. A detailed space-temporal picture of the distribution of radon variations on the earth’s surface is needed. 2. The procedure for separating radon exhalation data into normal and anomalous components should be developed. 3. An adequate model of the process of preparing a tectonic event in the earth’s crust is required. The first condition is the radon exhalation data obtained in Southern California, are satisfied. We propose a technique for separating radon exhalation data into normal and anomalous components, based on factor analysis. An adequate model of the process of preparation of the tectonic event, in our opinion, is the model of the dilatant inclusion. Space-temporal characteristics of the amplitude of the radon anomaly are probably highly dependent on local conditions, such as rock type and local hydraulic conditions. Some spatial features of radon anomalies are noted. So, it is likely that the zone of earthquake precursors represents a wide annular space, and radon anomalies are not observed near the epicenter of the earthquake.