Abstract：The failure of rockmass under seismic load is an intercrossing problem of multi-discipline，such as rock mechanics，engineering geology，earthquake engineering and seismology. In this paper，the two important dynamic loads，rock blasting and earthquake，are discussed firstly，and then the dynamic stress induced by seismic wave propagation and the strength characteristics of rock mass are compared. It is concluded that the main cause of rock mass failure under seismic load is tensile fracture of rock material and failure of discontinuities. The limit depth of rockmass failure under seismic load is put forward，and the important influences of in-situ stress and topography on types and extent of rockmass failure under seismic load are analysed.
