Stress and Strain
Definition of stress
A rubber band that is stretched from stress experiences ______ ____________
Elastic deformation
Definition of fault
Any fracture or system of fractures along which Earth moves
Definition of focus
Point of initial fault rupture where an earthquake originates that usually lies at least several kilometers beneath Earth's surface
Kinds of stress
Compression, tension, shear
Definition of elastic deformation
Causes materials to bend and stretch which the material returns to its original state when the stress is removed
What is the surface along which the movement takes place?
Fault plane
Which wave causes the most damage?
Surface wave
True or False: Rocks can be twisted, squeezed, and stretched
True
Definition of plastic deformation
Permanent deformation caused by strain when stress exceeds a certain value
Why are normal faults called "normal"?
They follow gravity where the hanging wall moves horizontally downwards
Which wave is the fastest?
Primary wave
Laboratory experiments on rock samples show WHAT KIND OF RELATIONSHIP between stress and strain?
Distinct relationship
Definition of elastic limit
The maximum extent or value to which a solid may be stretched without permanent alteration of size or shape
The footwall's angle at the top is always...
Greater than 90 degrees
How does a secondary wave move?
Moves up and down or side to side