The Main Recent Fault is a long right-lateral strike-slip fault running along the high northeastern edge of the Zagros Mountains in western Iran, roughly parallel to the older Main Zagros Thrust. It accommodates the sideways component of the oblique collision between Arabia and central Iran.
While the surrounding Zagros belt shortens by thrusting, the Main Recent Fault takes up horizontal motion, sliding the northwestern Zagros toward the northwest. It is one of the few clearly defined strike-slip faults in a region otherwise dominated by folding, and its trace can be followed for hundreds of kilometres.
The fault has produced destructive historical and modern earthquakes, including the 1909 Silakhor (Dorud) earthquake (magnitude about 7.4), which killed some 6,000 people in Lorestan province. Its persistent activity confirms that horizontal slip, not only crustal shortening, shapes the seismic hazard of northwestern Iran.