Soil radon time series: Surveys in seismic and volcanic areas

Soil radon surveys have been performed in a long term monitoring basis with SSNTD (LR 115 type II), in order to observe possible fluctuations due to h igh magnitude seismic events and volcanic eruptions. Five-year radon time s eries are available in stations located in an intense seismic zone located along the Pacific coast of Mexico. The series analyses have been performed as a function of the local seismicity and geological characteristics. A dis cussion is intended to explain the lack of biunivocal relation between sing le radon peaks and earthquakes for the long term monitoring data using SSNT Ds. Examples of short term;radon anomalies obtained with continuous probes are also discussed as a function of local earthquakes and meteorological pe rturbations. Additionally, complementary results from recent changes in the activity pattern of an active volcano indicate that degassing processes in duced anomalous soil radon emanation correlated with the volcanic activity changes.