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

摘要： 文中讨论了库水渗漏在水库诱发地震中的作用,经过分析研究现有的水库诱发地震资料及相关理论,类比蒸汽锅炉与重力热管的热工原理,提出了水库地震成因的超临界水二级相变孕震模型。模型在水库孕震的各阶段表现为:初始阶段,渗漏水在压力注射和重力作用下形成水塞密封盖层,在超临界温区的地层裂隙中引发二级相变循环对流;孕育阶段,地层原生裂隙在高围压条件下形成应力腐蚀、化学蚀变、温差应力破碎作用,从而原生裂隙更加发育,制造了更大的对流循环通道;临震突变阶段,在热管下部热交换区内的临界水热通量剧增,超临界水发生横向流动,向封盖层外部扩散;发震阶段,在超临界水重力热管的通量和热管上部交换区所形成的压力,超过地层或封盖层的破坏极限时,推动上部地层做活塞运动导致地震。

关键词: 水库地震, 超临界水, 二级相变, 对流循环, 孕震模型