KHKZIBG+2.1

toc =2.1 Earth's Crust in Motion=

**Vocabulary**

 * stress**: a type of force that acts on rocks to change the shape or volume.
 * earthquake**: shaking from the seismic waves from the movement of rock under Earth's surface.
 * shearing**: stress that forces a mass of rock in two different(opposite) directions.
 * tension**:stress force that pulls on rocks, making it so its thinner in the middle.
 * compression**: force that squeezes rocks until they break.
 * deformation**: any kind of change in volume or shape of rocks in earth's crust.
 * fault**: a break in earth's crust where slabs of crust slip past each other
 * strike-slip fault**: rocks on either side of a fault slip in an opposite sideways motion.
 * normal fault**: the fault is at an angle so one block of rock lies above the fault while the other block lies below fault.
 * hanging wall**: the piece of rock that hangs at the upper part.
 * footwall**: the piece of rock that lies below.
 * fault-block mountain**: when normal faults uplift a block of rock
 * reverse fault**: has the same parts of a normal fault, but the blocks move along a reverse fault.
 * folds**: bends in rock that form when compression shortens and thickens part of Earth's crust.
 * anticline**: a fold in rock that bends upwards like a bridge.
 * syncline**: a fold in rock that bends down into a dip.


 * plateau**: a big piece of flat land higher than sea level.

Types of Stress

 * Shearing
 * causes masses of rock to slip
 * Tension
 * stretches the rock, making it thinner
 * Compression
 * pushes rock make middle bend upwards

Kinds of Faults

 * Strike slip fault
 * two rocks slip past each other in a sideways, up, or down motion.
 * Normal fault
 * the fault is at an angle
 * one block of rock lies above the fault
 * other is below the fault
 * Reverse fault
 * same structure as a normal fault
 * reverse position
 * blocks in opposite direction

Friction along faults

 * anticlines and syncline