Compression
pushing together of rock massed
convergent plate boundary
Stresses
forces on rock
Tension
divergent plate boundary
Pulling apart of rock masses.
Elastically
- Size and shape deform, but rock returns to original form when stress is removed.
Deform
change shape
Plastic deformation
- Elastic limit of rock exceeded; shape changed permanently--- folds.
- Warmer, subsurface rock.Folds
During crustal deformaton, rocks are oftenbent into wavelike shaped
Anticlines
unfolded or arch-shaped rock layers.
Synclines
downfolds or trough-shaped rock layers.
Fault
- Sudden fault movement causes most earthquakes.
Normal faults
-Hanging wall moves down relative to footwall– tension, pulling away.
Reverse fault
Strike-slip faults
-Displacement is horizontal
-Like San Andreas Fault in California.
Hanging wall
hang a lantern
Footwall
Could stand