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=Earth's Crust in Motion=

Vocabulary

 * Earthquake:** 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.
 * tension:** a stress force that pulls on the crust stretching rock so that it becomes thinner in the middle.
 * Compression:** A stress force that squeezes rock until it folds or breaks.
 * 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.
 * Strike-slip fault:** When the rocks on either of the fault slip past each other sideways with little up or down motion.
 * Normal Fault:** When the fault is at an angle, so one block lies above the fault while the other block lies below the fault.
 * Hanging Wall:** The half of the fault that lies above.
 * Foot Wall:** The half of the fault that lies below.
 * Fault-Block Mountain:** When normal faults uplift a block of rock.
 * Folds:** Bends in rock that form when compression shortens and thickens part of Earth's crust.
 * Anticline:** A fold of rock that bends upward into an arch.
 * Syncline:** A fold of rock that bends down in the middle to form a bowl.
 * Plateau:** Large are of flat land elivated high above sea level.

Types of Stress

 * Shearing, tension, and compression work over millions of years to change the shape and volume of rock.

Kinds of Faults

 * Faults usually accur along plate boundaries, where the forces of plate motion compress, pull, or shear the crust so much that the crust breaks.
 * Strike-Slip Faults
 * Normal Faults
 * Reverse Faults

Mountain Building

 * Over millions of years, fault movement can change a flat plain into a towering mountain range.
 * Mountains Formed by Faulting
 * Mountains Formed by Folding
 * Anticlines and Synclines
 * Plateaus