| A | B |
|---|
| earthquake | the shaking and trembling that results from the movement of rock beneath Earth's surface |
| stress | a force that acts on rock to change its shape or volume |
| shearing | stress that pushes a mass of rock in two opposite directions and can cause rock to break and slip apart or to change its shape |
| tension | this type of stress pulls on the crust, stretching rock so that it becomes thinner in the middle; it occurs where two plates are moving apart |
| compression | this stress force squeezes rock until it folds and breaks. One plate pushing against another can compress rock like a giant trash compactor |
| deformation | any change in the volume or shape of Earth's crust |
| fault | a break in Earth's crust where slabs of crust slip past each other |
| hanging wall | with a normal fault, the half of the fault that lies above |
| footwall | with a normal fault, the half of the fault that lies below |
| strike-slip fault | the rocks on either side of the fault slip past each other sideways with little up-or-down motion |
| normal fault | the fault is at an angle, so one block of rock lies above the fault while the other block lies below the fault |
| reverse fault | compression forces produce these; it has the same structure as a normal fault, but the blocks move in the opposite direction |
| fault-block mountain | when normal faults uplife a block of rock |
| folds | bends in rock that form when compression shortens and thickens part of Earth's crust |
| anticline | a fold in rock that bends upward into an arch |
| syncline | a fold in rock that bends downward in the middle to form a bowl |
| plateau | a large area of flat land elevated high above sea level |
