THEY+2.1

toc =2.1 Earth's Crust in Motion=

Vocabulary
plateau**: is a land form that has more less leveled surface and that is elevated high above the level of th sea = = = =
 * earthquake:** when the earth shakes beneath the crust.
 * stress:** to change the shape on a rock.
 * shearing:** cause rock to slip past each other.
 * tension:** this causes to stretch rocks.
 * compression:** pushes the rock toward each other.
 * deformation:** is any change that happens to earth's crust.
 * fault:** is a break in the Earth's crust where groups of rock slide past each other.
 * strike-slip fault:** is a fault where rocks from different sides that move past each other in a up and down motion.
 * normal fault:** is a fault which has a hanging wall that slides downward, this is caused by tension in the crust.
 * hanging wall:** is a block of rock that forms on the upper part of a fault.
 * foot wall:** is the block of rock which forms the lower part of a fault.
 * reverse fault:** is a fault that has a hanging wall that slides upward.
 * fault-block mountain:** a mountain that is being created where a normal fault uplifts a block of a rock.
 * folds:** a bend in a rock that forms where the part of the Earth is compressed.
 * anticline**: an upward fold in a rock that is formed of the Earth's crust by compression.
 * syncline**: a downward fold in a rock that is formed in the Earth's crust by compression**.

**Stress in the Crust**

 * the movement in earthquakes result to forces that are called stresses
 * stress is a kind of force which changes the shape or volume of an object

**Types of Stress**

 * there are three different kinds of stress, the shearing, the tension, the compression, and the deformation stresses
 * each stress has a unique force of bending, stretching, breaking, tilting, folding, and sliding the Earth's crust

**Kinds of faults**

 * faults are breaks in the Earth's crust where a group of rocks slip past each other
 * fault usually appear where plate boundaries are,and where plate motions occurs
 * there are usually three types of faults, the strike-slip fault, the normal fault and the reverse fault
 * shearing is the stress that creates the strike-slip fault
 * by forming the boundary between two plates is also known as the transform boundary
 * tension forces create normal faults in the Earth's crust
 * normal faults go in an angle so on side goes up and one go down in a slanted direction
 * the half that goes upward is called the hanging wall and the half that goes downward is called the footwall
 * the compression force creates the reverse fault
 * the reverse fault is the same as the reverse fault, but the movement is in the opposite directions

**Friction along faults**

 * friction, a force that opposes the motion of one surface to another surface
 * depending on the fault there will be a certain amount of friction between the opposite side of faults

**Mountain Building**

 * the force of plate movements can build up the surface of the Earth
 * movements of faults can change a flat plain to a bumpy mountain
 * when a block of rock is uplifted by a normal fault it forms a fault block mountain
 * where two plates moved away from each other, the tension forces produce a lot of normal faults
 * hanging fault fault from each slips down
 * bends in rocks are called folds when the compression shortens part of the crust of the Earth
 * collisions of two plates can cause compression with two plates
 * fold that goes upward in an arch is called anticline and the opposite is called sycline
 * both anticline and sycline happen where compression takes place on the Earth's surface
 * forces that could raise mountains are the forces that raise plateaus
 * plateaus are a large area of flat plain land that has an elevation above sea level