2. Presentation on Terminology and different types of Faults
Prepaid by :-
Sr no.
Name
Enrollment number 1.
Kharadi chetan R.
Submit to :- Prof. Darshika Shah
Branch :- Civil eng.

3. Terminology 1) Fault plane 2) Fault trace
Faults may be vertical, horizontal, or inclined at any angle.
Although the angle of inclination of a specific fault plane tends to be relatively uniform, it may differ considerably along its length from place to place.
When rocks slip past each other in faulting, the upper or overlying block along the fault plane is called the hanging wall, or headwall.
2) Fault trace
A fault trace is the intersection of a geological fault with the ground surface, leaving a visible mark.
The term also applies to a line plotted on a geological map to represent a fault.

4. 3) Fault zone
In many cases, faulting takes place along a number of parallel fractures.
That is, total displacement is contributed over this zone.
Such a zone with contains a number of closely spaced sub-parallel fractures along which the relative displacement has taken place is called fault zone.

5. 4) Dip
The dip gives the steepest angle of descent of a tilted bed or feature relative to a horizontal plane, and is given by the number (0°-90°) as well as a letter (N,S,E,W) with rough direction in which the bed is dipping.
One technique is to always take the strike so the dip is 90° to the right of the strike, in which case the redundant letter following the dip angle is omitted.
The map symbol is a short line attached and at right angles to the strike symbol pointing in the direction which the planar surface is dipping down.
The angle of dip is generally included on a geologic map without the degree sign. Beds that are dipping vertically are shown with the dip symbol on both sides of the strike, and beds that are flat are shown like the vertical beds, but with a circle around them.

6. 5) Strike
The strike line of a bed, fault, or other planar feature, is a line representing the intersection of that feature with a horizontal plane.
On a geologic map, this is represented with a short straight line segment oriented parallel to the strike line. 
Strike can be given as either a quadrant compass bearing of the strike line or in terms of east or west of true north or south, a single three digit number representing the azimuth, where the lower number is usually given, or the azimuth number followed by the degree sign.

7. 6) Hade
Hade is the angle which the fault plane make with the vertical.
Hade = 90’ – dip of the fault.
7) Throw
The vertical component of the displacement of fractured rock blocks, is called the throw of fault.
The side on which the strata appear to have thrown is called the ‘down throw side’.
The side on which the strata appear to have gone up is called the ‘up throw side’.

8. 10) Hanging wall & Foot wall
8) Heave
The horizontal component of displacement of a fault is called the heave.
9) Net slip
The total displacement measured along the fault plane is called the net slip
10) Hanging wall & Foot wall
If the fault plane is inclined, the block lying over the fault is called the Hanging wall.
Whereas the block lying beneath the fault plane is called footwall.

9. Classification of Faults

10. [A] On the basis of the apparent movement of the fault blocks
1) Normal Fault
 Normal fault is one in which the hanging wall falls down relative to the foot wall due to tensional stress it is also called gravity fault/apparent normal fault.
Normal faults with very shallow dipping fault planes (<10 degrees) are called "detachment" faults or "decollemonts".

11. 2) Thrust Fault
A thrust fault is a type of fault, or break in the Earth's crust across which there has been relative movement, in which rocks of lower stratigraphic position are pushed up and over higher strata.
They are often recognized because they place older rocks above younger. Thrust faults are the result of compressional forces.

12. [B] On the basis of the amount of dip of the fault
1) High angle faults
These are those faults in which the fault plane dips steeply, at angles more than 45’, as generally happens in normal faults.
2) Low angle fault
These are those faults in which the fault planes dips gently, at angles less than 45’, as generally happens in thrust faults.

13. [C] On the basis of Attitude of the fold
1) Strike fault
A strike fault is that in which the strike direction of the adjacent beds i.e. the fault strikes along the strike of the beds.

14. 2) Dip fault
A dip fault is that in which the strike of the fault is normal (perpendicular) to the strike of the adjacent beds.

15. 3) Oblique fault
An oblique fault is that in which the fault plane strikes obliquely (diagonally) to the adjacent beds, i.e. fault plane strike neither parallely nor normally to the adjacent beds.