The Sagaing Fault is a major continental transform running some 1,400 kilometres north to south through the heart of Myanmar, passing close to the cities of Mandalay, Naypyidaw and Yangon. It accommodates most of the horizontal motion between the India Plate and the Sunda Plate, a boundary that plate convergence has partitioned into strike-slip along this fault and thrusting to the west.
It is a right-lateral strike-slip fault slipping at roughly 18 to 20 millimetres per year, one of the fastest-moving continental faults in Asia. Because it runs almost dead straight beneath the densely populated Irrawaddy corridor, ruptures here expose millions of people to intense shaking.
The fault has generated numerous large earthquakes, including a magnitude 7.7 event in 1946 and the devastating magnitude 7.7 Mandalay earthquake of March 2025, which ruptured a long segment near the fault's centre and caused widespread destruction and heavy casualties across central Myanmar.