Fault'classification of fault and mechanism of faulting
Final fault new
1.
2. Faults:Faults: Are fractures that have appreciable movement parallel to theirAre fractures that have appreciable movement parallel to their
plane.plane.
Faults may be hundred of meters or a few centimeters in length.Faults may be hundred of meters or a few centimeters in length.
FAULTFAULT
3. Fault planeFault plane:: Surface that theSurface that the
movement has taken placemovement has taken place
within the fault. On thiswithin the fault. On this
surface the dip and strike ofsurface the dip and strike of
the fault is measured.the fault is measured.
Hanging wall:Hanging wall: The rockThe rock
mass resting on the faultmass resting on the fault
plane.plane.
Foot wall:Foot wall: The rock massThe rock mass
beneath the fault plane.beneath the fault plane.
Fault planeFault plane:: Surface that theSurface that the
movement has taken placemovement has taken place
within the fault. On thiswithin the fault. On this
surface the dip and strike ofsurface the dip and strike of
the fault is measured.the fault is measured.
Hanging wall:Hanging wall: The rockThe rock
mass resting on the faultmass resting on the fault
plane.plane.
Foot wall:Foot wall: The rock massThe rock mass
beneath the fault plane.beneath the fault plane.
Parts of The FaultsParts of The Faults
4. Separation:Separation: The amount ofThe amount of
apparent offset of a faultedapparent offset of a faulted
surface, measured in specifiedsurface, measured in specified
direction. There are strikedirection. There are strike
separation, dip separation, andseparation, dip separation, and
net separation.net separation.
Heave:Heave: The horizontalThe horizontal
component of dip separationcomponent of dip separation
measured perpendicular to strikemeasured perpendicular to strike
of the fault.of the fault.
Throw:Throw: The vertical componentThe vertical component
measured in vertical planemeasured in vertical plane
containing the dip.containing the dip.
6. Types of Faults
•Dip-slip faults have movement
parallel to the dip of the fault
plane
–In normal faults, the hanging-wall block has
moved down relative to the footwall block
–In reverse faults, the hanging-wall block has
moved up relative to the footwall block
7. Types of Faults
•Dip-slip faults have movement
parallel to the dip of the fault
plane
–Fault blocks, bounded by normal faults, that
drop down or are uplifted are known as
Grabens and HORSTS, respectively
•Grabens associated with divergent
plate boundaries are called rifts
–Thrust faults are reverse faults with dip
angles less than 30° from horizontal
9. Thrust FaultThrust Fault
Thrust Faults: In the thrust
faults the hanging wall
has moved up relative to
the footwall (dip angle
30º or less)
Reverse Faults: Are similar
to the thrust faults
regarding the sense of
motion but the dip angle
of the fault plane is 45º
or more
Thrust faults usuallyThrust faults usually
formed in areas offormed in areas of
comperssional regime.comperssional regime.
12. Transform FaultsTransform FaultsTransform Faults:Transform Faults: Are aAre a
type of strike-slip faulttype of strike-slip fault
(defined by Wilson 1965).(defined by Wilson 1965).
They form due toThey form due to thethe
differences in motiondifferences in motion
between lithosphericbetween lithospheric
plates.plates.
They are basically occurThey are basically occur
where type of platewhere type of plate
boundary isboundary is
transformed intotransformed into
anotheranother..
