Kinds of FaultsKinds of Faults

FaultsFaults

Is a break in Earth’s crust where slabs of Is a break in Earth’s crust where slabs of crust slip past each other.crust slip past each other.

Usually occur along plate boundaries , Usually occur along plate boundaries , where the forces of plate motion where the forces of plate motion compress, pull, or shear the crust so compress, pull, or shear the crust so much that the crust breaks.much that the crust breaks.

Three Types of FaultsThree Types of Faults

Normal FaultsNormal Faults Reverse FaultsReverse Faults Strike-Slip FaultsStrike-Slip Faults

Fault TerminologyFault Terminology

Fault Plane - the plane along which the Fault Plane - the plane along which the rock or crustal material has fracturedrock or crustal material has fractured

Hanging Wall Block - the rock material Hanging Wall Block - the rock material which lies above the fault planewhich lies above the fault plane

Footwall Block - the rock material which Footwall Block - the rock material which lies below the fault plane. lies below the fault plane.

Hanging vs. FootHanging vs. Foot

The The footwallfootwall of a fault is always of a fault is always underunder the the faultfault

The The hanginghanging wall of a fault is always wall of a fault is always aboveabove the fault the fault

Normal FaultsNormal Faults

Caused by tension forces where plates Caused by tension forces where plates divergediverge

The fault is at an angleThe fault is at an angle One block lies above the fault (hanging One block lies above the fault (hanging

wall)wall) The other block lies below the fault The other block lies below the fault

(footwall)(footwall) When movement occurs along a normal When movement occurs along a normal

fault, the fault, the hanginghanging wall slips wall slips downwarddownward

Normal FaultsNormal Faults

Normal FaultNormal Fault

Hanging Wall

Footwall

Normal FaultsNormal Faults

Normal FaultsNormal Faults

Normal FaultsNormal Faults

Reverse FaultsReverse Faults

Caused by compression forces along Caused by compression forces along convergent plate boundariesconvergent plate boundaries

Has the same structure as a normal fault, Has the same structure as a normal fault, but blocks move in opposite directionbut blocks move in opposite direction

One side lies at an angle above the otherOne side lies at an angle above the other Where the Where the hanging wallhanging wall is displaced is displaced

upwardupward relative to the footwall relative to the footwall OROR where the footwall is displaced where the footwall is displaced

downward relative to the hanging wall downward relative to the hanging wall

Reverse FaultReverse Fault

Reverse FaultReverse Fault

Hanging Wall

Footwall

Reverse FaultReverse Fault

Reverse FaultReverse Fault

Reverse FaultReverse Fault

Strike-Slip FaultStrike-Slip Fault

Created by shearing along transform Created by shearing along transform boundariesboundaries

Rocks on either side of fault slip past Rocks on either side of fault slip past each other sideways with little up-or-each other sideways with little up-or-down motiondown motion

Strike-Slip FaultsStrike-Slip Faults

Strike-Slip FaultStrike-Slip Fault

Strike-Slip FaultStrike-Slip Fault

Strike-Slip FaultStrike-Slip Fault

Strike-Slip FaultStrike-Slip Fault

Whose Fault?Whose Fault?Side View

Whose Fault?Whose Fault?Side View

Whose Fault?Whose Fault?Birds-eye View

Whose Fault?Whose Fault?Side View

Whose Fault?Whose Fault?Side View

Whose Fault?Whose Fault?Birds-eye View

Whose Fault?Whose Fault?Side View