When does a fault occur?
a. a fault occurs when stresses in the crust cause land on one side of the fracture move in a relation to the other side
b. a fault occurs when folding in the crust causes land on one side of a fracture to stay even on the land on one side.
c. a fault occurs when folding in the crust causes land on one side of the fracture to move to relation to the other side.

Consider two less-than-desirable options. in the first you are driving 30 mph and crash head-on into an identical car also going 30 mph. in the second option you are driving 30 mph and crash head-on into a stationary brick wall. in neither case does your car bounce off the thing it hits, and the collision time is the same in both cases. which of these two situations would result in the greatest impact force?