aasssss

1. Geometry and
Classification of Faults
Name:- Kajal Rana
University :-Sri Dev Suman Uttarakhand University
Class:-M. Sc 1st Sem
Subject:-Geology
Paper:- 3rd ( Structural Geology)

2. Crustal Fractures:-
•Crustal fractures depends on the strength of rock and intensity
of tensional forces.
•Crustal fractures are divided into 2 types.
•Joints -A fractures along which no relative displacement of
rock block take place.
•Faults- A fractures along which relative displacement of rock
block take place.

3. Fault-
•A fault may be defined as a fracture along which blocks of rocks
have been displaced relatively to each other.
•Faults result from tensional as well as compressional force.

4. Fault terminology:-
• Fault plane:- The fracture plane along which relative movement has been take place is
called a fault plane. It may be vertical, horizontal, inclined, curved etc.
• Dip :-Angle between fault plane and horizontal surface.
• Strike:-Trend of line formed by intersection of fault plane and a horizontal plane .
• Hade:- Compliment angle of dip.
• Upthrown side:- It represent the upper most block of the fault.
• Downthrown side:- It represent the lower most block of the fault.
• Hanging wall and footwall:- If the fault plane is not vertical ,the block of rock lying
above is known as hanging wall and the block of rock lying below is known as Footwall.

5. • Vertical fault neither have footwall or hanging wall.
• Fault Scarp:- Steep wall like slope caused by faulting in crustal rocks.
• Throw:- The vertical component of the displacement of fractured rock block.
• Heave:- The horizontal component of the displacement of fractured rock block.
• Net slip:- Total displacement of rock blocks due to faulting is called net slip.

6. Classification of fault:
•On the basis of movement and displacement of rock
blocks.
•There are two types of fault-
•1 Dip slip fault
•2 Strike slip fault

7. Dip slip fault:-
•Fault formed by the displacement of blocks along the dip
direction is called dip slip fault.
•Dip slip fault also are two types.
1 Normal Fault
2 Reverse Fault

8. • Fault formed due to the displacement of both the rock blocks in opposite
directions down the dip .Fault plane usually between 45degree and the
vertical(90degree).
Normal fault

9. Reverse fault:-
• Fault formed due to the displacement of fractured rock blocks towards each other up
to the dip . The fault plane in a reverse fault is usually inclined at an angle between 40
degree and the horizontal (0 degree).

10. Strike slip fault :-
•Fault formed by the displacement of blocks along the
strike direction is called strike slip fault.
•Strike slip fault also are two types.
1- Left lateral sinistral fault
2- Right lateral dextral fault

11. Left lateral Sinistral fault:-
When the displacement of the rock blocks occur to the left
on the far side of the fault.
Right lateral Dextral fault:-
When the displacement of the rock blocks occur to the right on
the far side of the fault.

13. Over thrust fault:-
• When the compressive force exceeds thee strength of the rocks . One block of the
fault overrides the other block and the fault plane become almost horizontal.

14. Thrust fault:-
• A fault which has very small angle of hade ( inclination of the fault plane with the
vertical is very small) and the hanging wall had apparently gone up with respect to
footwall is called thrust fault.
Step Fault:-
• A series of faults occur in any area in such a way that the slope of all
the fault plane of the fault are in the same direction.

15. Step fault

16. THANK YOU