Question

Horst and graben structures are typically formed by

• A. normal faulting
• B. strike-slip faulting
• C. reverse faulting
• D. thrust faulting

Hint:

Horst and graben structures are typical of areas experiencing extension, where the crust is being pulled apart.

Answer 1

The Correct Option is A

Step 1: Understanding Horst and Graben.
Horst and graben are types of fault block mountains formed by normal faulting. A horst is an uplifted block, while a graben is a down-dropped block.
Step 2: Analyzing the options.
(A) normal faulting: Correct — Horst and graben structures are formed by normal faulting, where the crust is stretched and blocks move vertically.
(B) strike-slip faulting: Incorrect — Strike-slip faulting causes horizontal displacement, not the vertical movement required for horst and graben structures.
(C) reverse faulting: Incorrect — Reverse faulting involves compressional forces, which cause uplift and shortening of the crust, not the formation of horst and graben.
(D) thrust faulting: Incorrect — Thrust faulting involves compressive forces, not the normal faulting that forms horst and graben.
Step 3: Conclusion.
The correct answer is (A) normal faulting, as horst and graben structures are formed by vertical movement associated with normal faults.