关键词: 水库地震, 超临界水, 二级相变, 对流循环, 孕震模型

Abstract: Water leakage in a reservoir is considered as an important factor that induces reservoir earthquakes.But the mechanism is complicated.According to the thermal principle of steam boiler and gravity heat pipe,a new seismogenic model of supercritical water second-order phase transition is proposed.The model can be separated into the following four stages.In the initial stage,seeping water under the pressure and gravity forms a water seal cover.Then second-order phase transition cellular convection arises in the stratum fissure of the supercritical temperature zone.In the incubation stage, caused by the fashions of stress corrosion,chemical alteration and thermal stress,primary fissures in stratum under the high confining pressure develop.This action makes the primary fissures grow and then bigger cellular convection passages are formed.In the critical stage,the critical water flux in the lower heat exchange region increases sharply,and the supercritical water laterally flows and diffuses outside the sealing cover.In the last earthquake stage,the huge stress,which exceeds the limit of stratum or sealing cover,pushes the top stratum to move like piston and the earthquake occurs.

Key words: reservoir induced earthquake, supercritical water, second-order phase transition, convective circulation, seismogenic model