Seiemic waves caused by earthquake

1. As we have discussed in the previous article, earthquake happens when a huge amount of energy is released due tectonic plates movements. The immediate outcome of earth is sudden movement of the ground located in the vicinity of earthquake center. The huge amount of energy is transferred throughout the ground layers in all directions until it worn out. Unfortunately, the transfer of seismic waves means all structures in the way are endangered of damage of even collapse. In this article we are going to know more about different types of seismic waves caused by earthquake.
   Seismic waves
   Seismic waves can be divided into 3 categories including P-waves, S-waves and surface waves. The velocity and transfer mechanism of each one is different from others.
   p-waves are the fastest waves with a velocity of 330 ms-1 through air and 5000 ms-1 through granite layers. In other words, p-waves are the first waves recognized by seismographs. They are also called primary waves or pressure waves. P-waves frequently compress and expand the materials when they are passing through. And particle motion is in the direction of p-wave propagation.
   on the other hand, S-waves move the particles perpendicular to their propagation direction. S-waves are also slower and reaches after P waves. This is the reason for which we also call them secondary waves. However S-waves cannot travel through air or water but they are generally more destructive than P-waves because their amplitudes are larger.
   Both of P-waves and S-waves are body waves, which means they travel through the body of the material. but there are also another category of seismic waves that travel only on the surface of the material. Surface waves are the slowest and the most destructive ones. Their amplitude are by far larger than S-waves. Surface waves includes Love waves and Rayleigh waves.
   The propagation pattern of love waves is to move back and forth horizontally, while Rayleigh waves move the particles in both vertical and horizontal directions.
   All in all, Rayleigh waves are the most destructive amongst all.