The North Tabriz Fault is a major right-lateral strike-slip fault running about 150 kilometres across northwestern Iran, passing close to the historic city of Tabriz. It helps accommodate the northward push of Arabia into Eurasia by transferring motion across the Iranian Azerbaijan block.
Slipping at a few millimetres per year, the fault is clearly marked by offset streams, scarps and displaced landforms along the flank of the Sahand volcano. It is segmented, and different sections have ruptured in separate large earthquakes over the historical record.
The fault is notorious for repeatedly destroying Tabriz, most catastrophically in 1721 and 1780, when earthquakes each killed tens of thousands of people. Given the city's growth since then, the North Tabriz Fault is regarded as one of Iran's most dangerous seismic sources, with strain accumulated over more than two centuries of quiescence.