Reidel fractures are described as which of the following?

• A. Small faults striking at an angle to the main fault movement within the fault zone
• B. They are called R shears
• C. They are used to determine the slip direction along a fault
• D. All of the above

Answer: (D)

Reidel fractures are small synthetic shear fractures that form within a fault zone under shear. They typically strike at a small angle to the main fault movement, about 15 degrees, and they’re commonly called R-shears. Because their sense of shear aligns with the direction of slip along the fault, they provide useful information about the fault’s slip direction. All the statements describe Reidel fractures.