HYDROTHERMAL EXPLOSION DUE TO SEAL EFFECT IN EL HUMAZO GEOTHERMAL MANIFESTATION, DOMUYO VN., NEUQUÉN, ARGENTINA

Two loud explosions accompanied by two successive big dark clouds that would have been 300 metres high, had taken place at El Humazo geothermal manifestation at February 2003. These explosions produced some important geomorphologic and structural changes that were registered in the geothermal area and its surroundings. Among these, it can be mentioned the reactivation of a geothermal manifestation place 1,6 km from El Humazo, called Mallin del Domo. In addition the explosions had yielded stone blocks of breccias up to one tonne, scattered throughout the place. The mechanism propose for the explosions and disseminated breccias is the local sealing of nearsurface discharge channels and the transmission of deeper reservoir pressures to the sealed area by the evolution of a compressible cap of exsolved gas (dominantly CO2).