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**Earth's Crust in Motion**

 * Vocabulary**
 * 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.
 * Tension**- a force that stretches rock to make it thinner.
 * Compression**- a force that squeezes rocks 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 or crust slip past each other.
 * Strike-slip Faults**- a fault where rocks slip past each other sideways with little up-or-down motion.
 * Normal Faults**- a fault that has a hanging wall and footwall that slides downwards.
 * Reverse faults**- the exact opposite of a normal fault, which has a footwall and a hanging wall except sliding upwards.
 * Friction**- the force that opposes the motion of one surface as it moves across another surface.
 * Fault-block Mountain**- normal faults uplifting a block of rock.
 * folds**- bends in rock that form when compression shortens and thickens part of Earth's crust.
 * Anticline**- the 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.

Stress in the Crust

 * Stress
 * the force that changes the shape and volume of rock
 * adds energy to rock

**Types o****f Stress**

 * shearing
 * slip and breaks rock
 * tension
 * pulls on crust
 * stretches rock, so it becomes thinner in the middle
 * compression
 * squeezes rock till folds or breaks
 * like a giant trash compactor
 * deformation
 * changes in the earth's crust
 * changes in the earth's crust

Kinds of Faults

 * faults
 * a break in earth's crust
 * faults occur near boundaries

Strike-Slip Fault

 * shearing
 * causes strike-slip fault
 * boundaries form
 * called transform boundary
 * [[image:andyany12345.jpg width="402" height="238"]]

Normal Faults

 * tension
 * causes normal faults
 * rock slips
 * fault that lies above is hanging wall
 * fault that lies below is footwall

Reverse Faults

 * compression
 * causes reverse faults
 * reverse faults produce part of Appalachian Mountain

Friction Along Faults

 * Friction
 * a force that opposes the motion of one surface as it moves across another surface
 * Faults sometimes jam together because of friction
 * they will jerk free, which produces small earthquakes
 * stress is strong enough to overcome friction force

Mountain Building

 * forces of plates can build up earth's surface

Mountains formed by Faulting

 * Fault block mountain
 * forms when faults uplift a block of rock
 * Sierra Nevada of California is a fault-block mountain
 * Great Basin also has many ranges of fault block mountain
 * two plates move away from each other
 * creates many normal faults

Mountains formed by Folding

 * Folds
 * plate movement causes crust to fold
 * bends in rock that form compression
 * California's northern Coast Range are partly the result of folding

Anticlines and Synclines

 * A fold in rock that bends upward into an arch is Anticline
 * anticline is the Black Hills
 * Black Hill formed about 65 million years ago
 * A fold in rock that bends downwards into an arch is Syncline
 * syncline can be as large as Illinois
 * The Illinois Basin is a syncline that stretches very far

Plateaus

 * plateaus
 * the force that raises mountains
 * a large area of flat land above sea level
 * a lot of plateau lies more than 1500 meters above sea level

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