Engineering Geology Multiple Choice Questions on “Classification of Faults – 03”.
1. The phenomenon not associated with imbricate structures is ___________
a) Series of thrust blocks occur in close proximity
b) Thrust blocks are piled up one above another
c) All fault surfaces dip in the same direction
d) Thrust blocks aren’t piled up one above another
Answer: d
Clarification: When a series of thrust faults occur in close proximity, thrust blocks are piled up one above another and all the fault surfaces dip in same direction. The resulting interesting structure is known as an imbricate structure.
2. In the Himalayan Mountains, many well defined nappe zones have been recognized.
a) True
b) False
Answer: a
Clarification: In the Himalayan Mountains, many well defined nappe zones have been recognized among which may be mentioned the Kashmir Nappe, the Nappe zone of Shimla Himalayas and the Nappes of the Garhwal Himalayas.
3. Most common term used for strike-slip faults is ___________
a) Slip fault
b) Transform fault
c) Tranlational fault
d) Hinge fault
Answer: b
Clarification: There are some other terms used for strike slip faults such as lateral faults, transverse faults, wrench faults and transform faults. Of these, the transform faults are very common and denote strike slip faults specially developed in oceanic ridges.
4. The type of fault where the faulted blocks have been moved against each other in horizontal direction is ___________
a) Reverse fault
b) Hinge fault
c) Strike-slip fault
d) Vertical fault
Answer: c
Clarification: Strike-slip faults are defined as the faults in which faulted blocks have been moved against each other in an essentially horizontal direction. The fault plane is almost vertical and net slip may be measured in great distances.
5. Which fault is developed in oceanic ridges?
a) Wrench faults
b) Transform faults
c) Lateral faults
d) Transverse faults
Answer: b
Clarification: The transform faults are very common and denote strike slip faults specially developed in oceanic ridges.
6. San Andres fault is the best example of which type of fault?
a) Strike-slip fault
b) Vertical fault
c) Normal fault
d) Reverse fault
Answer: a
Clarification: The best example of a strike-slip fault is the great San Andres fault of California. It extends for almost about 1000 km in an NW-SE direction.
7. Identify the type of fault from the figure below.
a) Vertical fault
b) Reverse fault
c) Strike-slip fault
d) Hinge fault
Answer: b
Clarification: From the figure it is clear that the hanging wall has moved up with respect to the foot wall and hence clearly it is a reverse fault.
8. If the left block appears to have moved towards the observer, then which type of fault does it belong to?
a) Left-handed fault
b) Right-handed fault
c) Enecholon fault
d) Radial fault
Answer: a
Clarification: Strike-slip faults are further distinguished into right handed or left handed depending on the direction of movement of the block with respect to an observer: it is a left-handed fault if the left block appears to have moved towards the observer and a right handed fault if the right block seems to have moved towards the observer.
9. What are pivotal faults called as?
a) Reverse faults
b) Radial faults
c) Hinge faults
d) Normal faults
Answer: c
Clarification: Hinge faults are also called as pivotal or rotational faults. A hinge fault is characterised by a movement of the disrupted blocks along with a medial point called the hinge point.
10. The movement of blocks in hinge faults is ___________
a) Translational
b) Rotational
c) Lateral
d) Sliding
Answer: b
Clarification: The movement in hinge fault, is rotational rather translational.
11. Which is the rare type of fault?
a) Vertical fault
b) Reverse fault
c) Thrust fault
d) Hinge fault
Answer: d
Clarification: In hinge faults, the amount of displacement increases away from the hinge point. These are rather rare type of faults.
12. What is the displacement range of strata in San Andres fault?
a) 10 km to 100 km
b) 20 km to 80 km
c) 50 km to 200 km
d) 100 km to 500 km
Answer: c
Clarification: The strata is believed to have suffered displacement varying between 50 km to 200 km in the San Andres fault in California.