SHORT AND LONG-TERM RADON IN SOIL MONITORING FOR GEOPHYSICAL PURPOSES

The subduction of the Cocos Plate under the North America Plate define s a high risk seismic zone along the Pacific coast of Mexico. A seismi c gap has been identified at the Guerrero State as a place where a lar ge earthquake, up to M(S)=8.2, can occur within the next years. In thi s area an in-soil radon network, consisting of fixed SSNTD monitoring stations, has been operated during several years on a monthly exposure basis. A continuous radon probe that registers data on a short term b asis is also operating since recently. The results of the two radon de tection systems are compared and discussed as a function of the local seismic activity observed at the Guerrero coastal zone.