Kinds of Faults
Faults
 Is a break in Earth’s crust where slabs of
crust slip past each other.
 Usually occur along plate boundaries ,
where the forces of plate motion
compress, pull, or shear the crust so
much that the crust breaks.
Three Types of Faults
 Normal Faults
 Reverse Faults
 Strike-Slip Faults
Fault Terminology
 Fault Plane - the plane along which the
rock or crustal material has fractured
 Hanging Wall Block - the rock material
which lies above the fault plane
 Footwall Block - the rock material which
lies below the fault plane.
Hanging vs. Foot
 The footwall of a fault is always under the
fault
 The hanging wall of a fault is always
above the fault
Normal Faults
 Caused by tension forces where plates
diverge
 The fault is at an angle
 One block lies above the fault (hanging
wall)
 The other block lies below the fault
(footwall)
 When movement occurs along a normal
fault, the hanging wall slips downward
Normal Faults
Normal Fault
Footwall
Hanging Wall
Normal Faults
Normal Faults
Normal Faults
Reverse Faults
 Caused by compression forces along
convergent plate boundaries
 Has the same structure as a normal fault,
but blocks move in opposite direction
 One side lies at an angle above the other
 Where the hanging wall is displaced
upward relative to the footwall
 OR where the footwall is displaced
downward relative to the hanging wall
Reverse Fault
Reverse Fault
Hanging Wall
Footwall
Reverse Fault
Reverse Fault
Reverse Fault
Strike-Slip Fault
 Created by shearing along transform
boundaries
 Rocks on either side of fault slip past
each other sideways with little up-ordown motion
Strike-Slip Faults
Strike-Slip Fault
Strike-Slip Fault
Strike-Slip Fault
Strike-Slip Fault
Whose Fault?
Side View
Whose Fault?
Side View
Whose Fault?
Birds-eye View
Whose Fault?
Side View
Whose Fault?
Side View
Whose Fault?
Birds-eye View
Whose Fault?
Side View