Which mountain range runs through Iran and Iraq and is a major source of earthquakes?

The Zagros Mountains run through Iran and Iraq and are a major source of earthquakes.

The Zagros form a long fold-and-thrust mountain belt across western Iran and northeastern Iraq, with extensions toward southeastern Turkey. They were created by the continuing collision of the Arabian Plate with the Eurasian Plate. That collision compresses and folds layers of sedimentary rock, producing both the mountains and their active faults.

Because the plate convergence is still underway, the Zagros remain one of the seismically active regions of the Middle East. Earthquakes occur on thrust and strike-slip faults throughout the range. The 2017 Iran–Iraq earthquake, which had a magnitude of about 7.3–7.4, occurred within the Zagros fold-and-thrust belt and caused severe damage near the border.

The Zagros are also important for human geography and natural resources. They contain extensive limestone formations, support oak forests and pastoral communities, and host major oil fields in western Iran. The Taurus Mountains are nearby in Turkey, while the Alborz lie farther north in Iran, so neither is the best answer to this question.