A fault is a fracture along which rocks have moved past each other, characterized by components such as the fault plane, hanging wall, and footwall. Types of faults include normal, reverse, thrust, vertical, dip-slip, strike-slip, oblique-slip, and step faults, each defined by their specific displacements and orientations. Evidence of faulting can be found in lithological and physiographic forms, including slickensides and fault scrapes.

2. FAULT
• What is a Fault ?
A fault is a fracture discontinuity along which
the rocks on either side have moved past each
other .

4. PARTS OF FAULT

5. THE PARTS OF A FAULT
• 1. Fault plane.
• 2. Hanging wall and Footwall.
• 3. Hade.
• 4. Throw.
• 5. Heave.

6. 1. Fault plane: A plane along which the
rupture has actually taken place or where
one block is moved with respect to other is
known as ‘Fault Plane’. It may be noted
that such a plane is generally formed along
the line of least resistance.

7. 2. Hanging wall and Footwall:
• The upper block or, in other words, the block
above the fault plane is called ‘Hanging wall’.
The block below the fault plane or, in other
words, beneath the fault plane is called the
Footwall.

8. 3. Hade:
It is the inclination of the fault plane
that is vertical.
4. Throw:
It is the vertical displacement between
the Hanging wall and Footwall.
5. Heave:
It is the horizontal displacement
between the Hanging wall and Footwall.

9. TYPES OF FAULTS
• NORMAL FAULT
• REVERSE FAULT
• THRUST FAULT
• VERTICAL FAULT
• HORST FAULT
• TRENCH FAULT
• DIP SLIP FAULT
• STRIKE SLIP FAULT
• OBLIQUE FAULT
• STEP FAULT

10. 1. Normal Fault:
• A fault in which Hanging wall (HW) has
apparently come down with respect to
the Footwall (FW) is termed as ‘Normal
Fault’.

11. 2. Reverse Fault:
• A fault in which hanging wall has
apparently gone up with respect to the
Footwall is termed as ‘Reverse Fault’.

12. What is the difference between a
normal fault and a reverse fault ?
• The only difference between the Normal Fault
and Reverse Fault is that, in Normal Fault the
Hanging wall is downward with respect to the
Footwall whereas in a Reverse Fault the
apparent movement of the Hanging wall is
upwards with respect to the Footwall.

13. 3. Thrust Fault:
• A fault which is a very small angle of hade
(i.e. the inclination of fault plane with the
vertical plane is very small) and the Hanging
wall that apparently goes up with respect to
the Footwall is called ‘Thrust Fault’.

14. 4. Vertical Fault:
• A fault in which the fault plane is vertical
(having an angle of hade up to 5 degrees) and
either of the walls has moved upwards or
downwards.

15. 5. Horst Fault:
• Horst (German, Horst = upthrow) Fault is one
in which wedge shaped block has gone up
with respect to the side blocks.

16. HORST & GRABEN

17. 6. Graben Fault or Rift Fault or
Trench fault:
• 6. Graben Fault or Rift Fault or Trench fault:
• Graben (German, Graben= Trench)Fault is one
in which wedge shaped block has down with
respect to side block.

18. 7. Dip Slip Fault
• Dip-slip faults are inclined fractures where the
blocks have mostly shifted vertically.

19. 8.Strike Slip Fault
• A fault is a fracture in the earth. These cracks
will run through rock and soil and anything
else that gets in the way. When the earth
moves parallel to the fracture, we call it
a strike-slip fault. Another way to think of this
is as a side-to-side motion.

20. Difference between a Strike-Slip
Fault and a Dip-Slip Fault ?
• Based on direction of slip and movement
along the fault plane. Dip slip - fractures
where the blocks have mostly moved vertically
Strike slip – vertical (or nearly vertical)
fractures where the blocks have mostly moved
horizontally.

21. 9.Oblique Slip Fault
• A fault which has a component of dip-slip and
a component of strike-slip is termed
an oblique-slip fault. Nearly all faults will have
some component of both dip-slip and strike-
slip, so defining a fault as oblique requires
both dip and strike components to be
measurable and significant.

23. 10. Step Fault:
• The term ‘Step Fault’ is applied to that parallel
fault where downthrown of all is in the same
direction and it gives a step-like arrangement.
What is
parallel fault ?

24. Parallel Fault
• A series of faults running more or less parallel
to one another and all handing in the same
direction is called ‘Parallel Fault’.

25. Field Evidence of Faulting:
• 1. Lithological Evidence
• 2. Physiographic Evidence

26. 1. Lithological Evidence
i. Slickensides,
ii. Fault Breccia and Gouge,
iii. Drag,
iv. Dislocations,
v. Repetition and Omission of Beds,
vi. Abrupt Termination of Structures, and
vii. Silicification and Mineralization.

27. • Slickensides:The movements of one wall against
another along fault results in polishing and grooving
of one or both surfaces.
• Fault Breccia and Gouge:Along some faults the
rocks are found highly fractured or even crushed to
angular fragments.
• Drag:Drag is the minor folding of strata along the
walls of a fault. It is caused by fault displacement.
• Dislocations:The displacement of beds, igneous
dykes; veins, etc. along a fault may be seen in either
plan or section.
• Repetition or Omission of Beds:The repetition and
omission of beds often establish the fault.

28. •Abrupt Termination of Structures : An
abrupt termination of structures such as folds,
beds or dykes along a common line or zone
suggests faulting.
Silicification and Mineralization : Action
water while percolation through a fault zone
may deposit fine-grained Quartz causing
Silicification. Many mineral deposits have also
been localized along faults.

29. Physiographic Evidence:
• Fault Scrap: An actual surface of fault
displacement may stand up unmodified by
erosion as in escarpment or cliff. It is called a
‘Fault Scrap’. In this case the escarpment faces
towards the down throw side.
• Fait Line Scrap : Fault frequently brings together
resistant and non-resistant rocks. The resistant
rock will stand out prominently as ridge along a
fault zone. Such ridges that will generally face the
upthrow side of the faults are called ‘Fault Scrap
Side’.

30. • Fault Control or Streams : Streams may be
guided in the direction and course of their
flow by faulting such stream, which may
follow a straight line or make approximately
right angle turns.