Earth's Moving Surface Forces of tension, compression and shearing changes the rock layers in the earth's crust. Tools A B stress forces that push and pull the crust anticline upward fold in a rock compression stress that squeezes rocks together crust surface layer of the earth deformation change in shape or volume of rocks dome raised area formed by magma pushing upward fault-block mountain formed by uplifted rocks fault break or crack in rock fold bend in rock foot wall block of rock below a fault hanging wall block of rock above a fault lateral fault blocks move horizontally past each other normal fault hanging wall moves down reverse fault hanging wall moves up Richter scale measures strength of earthquakes S wave side to side earthquake wave P wave push-pull earthquake wave epicenter point on earth's surface above the focus focus underground point of origin of earthquake seismic wave earthquake wave seismograph machine that records earthquake waves shearing pushes rocks in opposite, horizontal directions surface wave up and down earthquake wave tension stress that pulls rocks apart syncline downward fold in a rock thrust fault hanging wall slides over foot wall tsunami giant sea wave caused by an earthquake volcanic dust small rock particles blown into air volcano molton rock breaks through earth's crust