The Dasht-e Bayaz Fault is an east-west trending left-lateral strike-slip fault in the Khorasan region of eastern Iran, part of the complex network of faults that accommodates deformation between the Central Iran and Afghan blocks. It cuts across arid highlands and small farming villages in a remote and tectonically active region.
The fault accommodates horizontal shear within the broad zone of continental collision between the Arabian and Eurasian plates. Its surface trace is well expressed in the landscape, with clear offsets of streams and other features recording repeated left-lateral movement over time.
The fault is best known for the catastrophic 1968 Dasht-e Bayaz earthquake of magnitude 7.1, which produced a surface rupture some 80 kilometres long and killed more than 12,000 people. A related segment ruptured again in the 1979 Khuli-Boniabad earthquake, making this fault one of the classic examples of continental strike-slip earthquakes.