Download EQ Faults - smsk

EQ Faults
How EQ occur
• Plates moving past each
other snag onto each
other and building up
stress until it snaps
• Stress builds up in rock;
rock cannot contain the
force and:
– snaps
– Moves along faults
– Return to original
position
Types of Forces that cause EQ
• 3 types of forces acting
on rocks;
– Tension – pull apart
– Compression – push
together
– Shear- slid past each other
3 types of plate boundaries
divergent
convergent
transform
3 types of faults
• Each type of fault is the
result of the type of
forces acting on the
earth.
• Each type of fault
produces different kinds
of mountain making.
• Normal Faults:
– Tension forces
– Rock moves downward
– What kind of plate
boundary?
• Reverse Fault
– Compression forces
– Forced upward and over
rock below it
– What kind of plate
boundary?
• Strike-slip Faults
– Rocks on either side
move past each other
– Shear forces
– Ex; San Andreas Fault
Results of Faults
• Folded Mountains –
result of compression
forces
• Ex: Appalachian
•
Rockies
• Anticline – upward
bend in rock layers
• Syncline – downward
bend in rock layers
• Upwarped mountains –
blocks of earth’s crust
pushed up
• Ex: Adirondack Mts. NY
• Fault Block Mts. – huge,
tilted blocks separated
from surrounding rock
by faults.
– One block pushed up
while other dropped
down.
– Ex. Sierra Nevada