What kind of faults are more likely to form at divergent boundaries?

• A. Normal faults
• B. Reverse faults
• C. Strike-slip faults
• D. Oblique-slip faults

Answer: (A)

Dividing plates pull apart, causing the crust to be stretched and thinned. That extensional stress makes the rock crack and blocks slide down along fractures, producing normal faults where the hanging wall moves downward relative to the footwall. This style of faulting accommodates the widening of the crust and is characteristic of features like rift valleys and the fault patterns at mid-ocean ridges. While some complex faulting can occur if there’s additional shear, the dominant force at divergent boundaries is pulling apart, so normal faults are the most likely. In contrast, compression would create reverse faults, and pure shear from transform motion would create strike-slip faults. Oblique-slip can happen when both extension and shear are present, but not as the primary pattern at simple divergent boundaries.