The type of stress that causes fault-block mountains is tension (extensional stress), not compression, shearing, or subduction.

Quick Answer

  • Fault-block mountains form where the crust is being pulled apart.
  • This pulling-apart force is called tensional stress or tension.
  • Tension creates normal faults , which uplift some blocks (mountain ranges) and drop others (valleys or basins).

So, out of the choices compression, shearing, subduction, tension , the correct answer is: tension.

Fault-block mountains = normal faults = tensional stress (crust stretching, not squeezing).

TL;DR: The stress that causes fault-block mountains is tension. Information gathered from public forums or data available on the internet and portrayed here.