The geologic process is fracturing or faulting if the rock breaks and moves, and fracturing/jointing if it breaks without major movement. In simple geology terms, cracks or breaks in rock are usually called fractures , and they often form from stress, cooling, or tectonic forces.

Quick Scoop

  • Fracture = a break or crack in rock.
  • Joint = a fracture with little or no movement.
  • Fault = a fracture where the rock blocks move relative to each other.
  • These can form from tectonic stress , cooling , or other geological forces.

So the best single answer is: fracturing. If movement along the break is included, then it becomes faulting.

TL;DR

Cracks or breaks in rock are generally called fractures ; if the broken pieces move, it is faulting.