Part II. Introduction to Earthquakes. Question 1. What happens to rocks during an earthquake?
A. In a fault zone, as the strain in the rocks gradually builds up over time, the rock blocks are bent on either side of the fault and undergo elastic deformation.
B. Tectonic forces overcome the shear strength of the rock. The rock breaks, or undergoes brittle deformation, along the fault plane and can slip.
C. Energy is released when the rocks break or undergo brittle deformation. The release of strain causes the rock to unbend or undergo elastic rebound.
D. The generation of seismic waves and ground shaking.