在上一讲,介绍了震相的定义:“地震震相,是指在真实地震图和模拟地震图上,我们目前能判断其性质和种类,即能反映震源、介质和仪器一定信息的规则地震波形或波列。”由此可见,地震震相的物理基础是地震波,即地球介质振动的激发、传播和接收。其中,振动在非均匀的地球介质中传播,是形成不同性质和不同类型露相的主要原因。描述质点振动大小及其传播方向的是惠更斯—费涅尔原理。这个原理的要点是:(1)新波阵面是原波阵面子波包迹;(2)新波阵面的强度是原波阵面子波的迭加(同相增强,反相减弱)。以上这两点,不仅适用于均匀介质,而且适用于含有间断面的非均匀介质。这个 In the last lecture, the definition of seismic facies was introduced: “Earthquake facies refers to the rules that can judge the nature and type of seismic seismograms and simulated seismograms, that is, reflect certain information of seismic sources, media and instruments Seismic Waveform or Wavelet. ”Thus, the physical basis of an earthquake’s seismic phase is seismic waves, ie excitation, propagation and reception of the Earth’s medium vibration. Among them, the vibration in the non-uniform propagation of the Earth’s medium is to form a different nature and different types of the main reason for the dew. The Huygens-Fresnel principle is used to describe the magnitude of particle vibration and its propagation direction. The main points of this principle are: (1) the new wavefront is the original wavefront wavelet envelope; (2) the new wavefront intensity is the superposition of the original wavefront wavelet (in-phase enhancement, inverse reduction). These two points not only apply to uniform media, but also to non-uniform media containing discontinuities. This one