Strike-Slip Faults

Normal faults, reverse faults, and thrust faults all involve a substantial amount of vertical motion. This makes them relatively easy to spot in a road cut or mountain side. Strike slip faults involve motion in a horizontal plane: they are best spotted from the air! Strike-slip faults are either right-lateral or left-lateral. To determine what type you've got, figure out which way a particular object, say a road or a fence, was offset by the fault motion. If you have to go to your right to make the connection, you have a right-lateral fault. If it requires a jog to the left, it was a left-lateral fault that did the offsetting.

This is the remains of a cinder cone that erupted along a strike-slip fault in the southern end of Death Valley, CA. Note how the volcano was ripped in two. Because you have to step to the right to go from one side of the volcano to the other, this is a right-lateral strike-slip fault.
This cat has just spotted some strike-slip fault motion. Was it right or left lateral? This cat has six toes on all four feet. It can count higher than most cats.

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