The P waves undergoes compression and dilation during motion in its direction of propagation. This waves reaches the station first because the P waves travels at a speed, that is much faster in comparison to the S waves. The S waves are the secondary waves and are commonly known as the shear waves.
The P waves have the ability to travel in both solid as well as in liquid, whereas the S waves can propagate only in solid region because they are absorbed at the core-mantle boundary.
Thus, the P waves will arrive the station first and the difference between the arrival of P and S waves are plotted in the graph that helps in depicting the epicenter and the amount of energy released during an earthquake.
The P waves vibrate very quickly out from the epicenter first in all directions, in a circular way passing the station. The S waves then vibrate out from the epicenter a few seconds later and cause the sideways shaking of the land as they pass the station. The P wave then reflects off the core of the Earth and bounces back past the station, followed by the S wave a few seconds later because both waves reflect off the earths core back to the epicenter.
<span>Postthrombotic syndrome involves the formation of blood clots in the body and that is its hallmark. Some of the symptoms include leg pain and swelling. Lipodermatosclerosis involves problems with veins in the leg and is evident by changes in the lower legs.</span>
