Carrying on from what Jesse mentioned, this is how those faults work.
To release the energy (stress) that has built up inside the rocks, faults will move in a particular way. They can move up and down, side to side or a combination of both. Faults are made up of a footwall and hanging wall. Visualise the footwall on the left and the hanging wall on the right (just as an example).
1) Normal Fault: Up and down motion, so the footwall moves up and the hanging wall moves down.
2) Reverse (or Thrust) Fault: up and down motion again BUT hanging wall moves up, footwall moves down.
3) Strike-slip Fault: side to side motion (no up and down motion at all, if you now visualise a road running across the fault). You can get dextral strike slip faults (road moves left) and sinistral strike slip faults (road moves right)
4) Oblique slip Fault: combination of up and down motion and side to side motion. Footwall moves up and left, hanging wall moves down and right (for example)
Faults are really fun to explore using blocks made of cake. My structural lecturer showed us a picture of a demonstration that he did with cake blocks during my undergrad. Geology + food = pure awesomeness.
I agree with Jesse and Rehemat. I would like to add that the dip of the fault is important in classifying faults. Dip refers to the angle of inclination of the fault from horizontal. A flat fault would have a dip of 0° while a vertical fault would have a dip of 90°. Faults that are not horizontal nor vertical will be dipping to a particular orientation. The block of rock underneath the fault is called the footwall because miners that followed ore deposits along faults would stand on the lower block. The block above the dipping fault is called the hanging wall because that is where the miners would hang the lamps while removing the ore from the fault.
The name of the fault will depend on the relative movement of the hanging wall with respect to the footwall. As Rehemat explained, in the reverse fault the hanging wall will move up with respect to the footwall and in a normal fault, the hanging wall will move down with respect to the footwall. Note that a vertical fault with one block moving up is neither a reverse or normal fault as there is no hanging wall or footwall. Also, this classification does not work for horizontal faults. But since vertical and horizontal faults are rare, the classification mentioned by Jesse and Rehemat is pretty good. Most faults are oblique slip, which combine a vertical and horizontal movement.
The question has been answered perfectly by the other 3 scientists. If I may, I will add a very useful video link, which will help you visualise the different processes:
Let’s see there are 4 types of general faults:
1) Normal Fault
2) Reverse (or Thrust) Fault
3) Strike-slip Fault
4) Oblique slip Fault
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Carrying on from what Jesse mentioned, this is how those faults work.
To release the energy (stress) that has built up inside the rocks, faults will move in a particular way. They can move up and down, side to side or a combination of both. Faults are made up of a footwall and hanging wall. Visualise the footwall on the left and the hanging wall on the right (just as an example).
1) Normal Fault: Up and down motion, so the footwall moves up and the hanging wall moves down.
2) Reverse (or Thrust) Fault: up and down motion again BUT hanging wall moves up, footwall moves down.
3) Strike-slip Fault: side to side motion (no up and down motion at all, if you now visualise a road running across the fault). You can get dextral strike slip faults (road moves left) and sinistral strike slip faults (road moves right)
4) Oblique slip Fault: combination of up and down motion and side to side motion. Footwall moves up and left, hanging wall moves down and right (for example)
Faults are really fun to explore using blocks made of cake. My structural lecturer showed us a picture of a demonstration that he did with cake blocks during my undergrad. Geology + food = pure awesomeness.
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I agree with Jesse and Rehemat. I would like to add that the dip of the fault is important in classifying faults. Dip refers to the angle of inclination of the fault from horizontal. A flat fault would have a dip of 0° while a vertical fault would have a dip of 90°. Faults that are not horizontal nor vertical will be dipping to a particular orientation. The block of rock underneath the fault is called the footwall because miners that followed ore deposits along faults would stand on the lower block. The block above the dipping fault is called the hanging wall because that is where the miners would hang the lamps while removing the ore from the fault.
The name of the fault will depend on the relative movement of the hanging wall with respect to the footwall. As Rehemat explained, in the reverse fault the hanging wall will move up with respect to the footwall and in a normal fault, the hanging wall will move down with respect to the footwall. Note that a vertical fault with one block moving up is neither a reverse or normal fault as there is no hanging wall or footwall. Also, this classification does not work for horizontal faults. But since vertical and horizontal faults are rare, the classification mentioned by Jesse and Rehemat is pretty good. Most faults are oblique slip, which combine a vertical and horizontal movement.
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Wow, I studied seismology too long ago to remember this, thanks for the question, so I can also read the answers 😉
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The question has been answered perfectly by the other 3 scientists. If I may, I will add a very useful video link, which will help you visualise the different processes:
Thrust fault: http://earthquake.usgs.gov/learn/animations/animation.php?flash_title=Thrust+Fault&flash_file=thrustfault&flash_width=220&flash_height=320
Normal fault: http://www.youtube.com/watch?v=vqWCpo-1jrU
Strike-slip fault: http://earthquake.usgs.gov/learn/animations/animation.php?flash_title=Strike-Slip+Fault&flash_file=strikeslip&flash_width=240&flash_height=310
Oblique fault: http://www.youtube.com/watch?v=eY5Ec75Jj2c
Hope these help! 🙂
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