Which of the following faults, responsible for earthquakes' origin, is initiated only by tensile stress?

Correct option is A

Explanation The correct answer is (a) Normal fault. A normal fault is caused by tensile stress, where the Earth's crust is pulled apart. In this type of fault, the hanging wall moves downward relative to the footwall due to the extension of the crust.
Breakdown of Other Options:
1. (b) Thrust fault:
· Caused by compressional stress. In a thrust fault, the hanging wall moves up relative to the footwall.
2. (c) Strike slip fault:
· Caused by shear stress. In a strike-slip fault, the blocks of the crust move horizontally past each other.
3. (d) Oblique slip fault:
· A combination of tensile and shear stress. It has both vertical and horizontal movements.
Information Booster 1. Types of Faults and Their Stresses:
· Normal Fault: Tensile stress (extension).
· Thrust Fault: Compressional stress (shortening).
· Strike Slip Fault: Shear stress (horizontal sliding).
· Oblique Slip Fault: Combination of tensile and shear stress.
2. Earthquake Generation:
· Earthquakes occur when stress builds up along faults and is suddenly released, causing the ground to shake.
3. Key Characteristics of Normal Faults:
· Associated with divergent plate boundaries.
· Common in regions experiencing crustal extension (e.g., rift valleys).
Additional Knowledge · Hanging Wall: The block of rock that lies above the fault plane.
· Footwall: The block of rock that lies below the fault plane.
· Examples of Normal Faulting:
· The East African Rift and the Basin and Range Province in the western United States.