On the monitoring of subsoil radon at forecasting test sites

Instrumental and technique bases of measuring variations of subsoil radon concentration at forecasting test sites of the Central Asia seismoactive regions: geologic-geophysical substantiation of site selection for regime observation, expedience of usng either method of concentration recording, beasibility of instruments and technique for providing sensitivity and optimal frequency of measurements-are considered. Regime observations on the subsoil radon field variations were performed over tectonic disturbances overlapped with loose deposit mantle by the method of the passive registration of radon concentration from gamma-radiation of its decay products. It is established that the amplitude and nature of anomalous concentration variations depend on geologic-geophysical conditions of the radom field formation and deformation regime of radional rocks. Therefore requirements for instrument sensitivity, to methods and frequency of measurements performed must be determined above all by the anomaly amplitude and extension, level of natural and technogenic noise