From class, earthquake is any shaking or rapid motion of the Earth's solid layer. the plate tectonics cause stress on rocks which leads to breakage and breakage causes energy which causes earthquake :)
There are also different types of Earthquake waves such as P. Waves, S. Waves, and Surface Waves
-P.Waves: "Primary" or "push-pull" and it travel faster than other waves
-S. Waves: "Secondary" or "side-to-side" and it leaves the epicenter at the same time as the P. Waves but travel slower and it reaches the location after the
P.waves hit
-Surface wave is the strongest and it only travel on the crush. it is a combo of the P. and S. waves