When stress on rocks becomes too great, they break, and then undergo:

foreshocks
aftershocks
elastic rebound
compression

elastic rebound. I know this because I learned it in 8th grade. :)

elastic rebound

Explanation:

The elastic rebound theory states that the rocks experience fault and shift due to the force exerted on them by the seismic activity of the earthquakes. The rocks in the case of earthquake according to this theory accumulates energy and deform slowly until the internal strength of the rocks is exceeded.