The Chaman Fault is a major left-lateral strike-slip fault about 850 kilometres long running along the border between Pakistan and Afghanistan, from near the Makran coast up past Quetta and Kabul. It marks the western transform boundary of the India Plate as it slides northward past the Eurasia Plate.
Moving at roughly 10 to 35 millimetres per year depending on the segment, it takes up the sideways component of India's collision with Asia, the mirror of the thrust-dominated Himalaya to the east. The fault passes very close to the crowded city of Quetta, placing large populations at risk.
The fault system is linked to some of the region's deadliest earthquakes, including the catastrophic magnitude 7.7 Quetta earthquake of 1935, which destroyed the city and killed tens of thousands of people. Ongoing creep and moderate quakes continue to remind the region of its active hazard.