< p >一个人不会比表面波探测其他(爱和瑞利波)。后来身体波浪阶段非常低振幅,只检测到一个敏感的地震检波器。同样,在很短的抵消,通常很难挑选后阶段,即使他们发生。有临界角地震< a href = " https://en.wikipedia.org/wiki/Seismic_refraction " rel = " nofollow noreferrer " >折射< / >,但不是< a href = " https://en.wikipedia.org/wiki/Reflection_seismology " rel = " nofollow noreferrer " > < / >。0-offset反射产生下方。< / p > < p >地幔边界代表在弹性性质发生较大变化,因此一些能量将反弹到表面。我们称这些< a href = " http://www.isc.ac.uk/standards/phases/ " rel = " nofollow noreferrer " > < / > < em >卡式肺囊虫肺炎阶段< / em >, < em > ScP < / em >和< em > ScS < / em >阶段(Pressure-core-Pressure等等)。卡式肺囊虫肺炎是反射纵波和ScS反射横波。ScP波是一个有趣的现象,因为它的形成是横波的一部分能量转换为P波和反射。也有更高的订单能被探测到的地震波阶段(或模拟)合成地震震中附近PcP2 ScS2如。(如图)。 The PKiKP is a reflection from the inner core. 
The travel time diagram gives a rather good idea of when to expect seismic phases at different distances from the earthquake. The distance is in degrees, so 180$^\circ$ is on the opposite side of the planet. Note how the core shields all direct shear waves, that is why we know that the outer core is fluid.