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前言 我国大陆地震大都发生在莫霍界面以上的地壳内,属于浅源地震。不论是浅源地震还是深源地震,波从震源发出后,在传播过程中,遇到介质界面便要发生反射现象。形成地震波全反射的条件是:地震波在地壳介质传播过程中必须遇有明显的介质界面;地震波必须先从低传播速度的介质中入射,透过界面传向高传播速度的介质中,并同时发生远离法线的折射;入射波的入射角必须大于临界角。若上述三个条件得到满足,地震波则在界面发生全反射。这是广义的描述地震波全反射现象。广义的地震波全反射波可以在较远的距离观测到,例如地面爆破反射波P_(11)、S_(11)在震中距180公里左右仍可清晰地记
Preface Most of the earthquakes in China occur within the crust above the Moho interface and belong to shallow-source earthquakes. Whether it is a shallow source earthquake or a deep source earthquake, the wave is reflected from the source interface when it encounters the media interface after it is transmitted. The conditions for the formation of total reflection of seismic waves are that the seismic waves must have obvious media interfaces during the propagation of the crustal medium. The seismic waves must first be incident on the medium with low propagation velocity and propagate through the interface to the medium with high propagation velocity, Far from the normal of the refraction; incident wave angle of incidence must be greater than the critical angle. If the above three conditions are satisfied, the seismic wave is totally reflected at the interface. This is a generalized description of the total reflection of seismic waves. The generalized total reflection of seismic waves can be observed at far distances. For example, the reflected waves P_ (11) and S_ (11) of the ground blasting can still be clearly recorded at a distance of about 180 km