A scar across a nation
The Sagaing Fault is a massive, 1,400-kilometer-long right-lateral strike-slip fault that runs the length of Myanmar. It marks the boundary between the Indian Plate and the Sunda Plate, taking up about half of their relative motion. This geological feature connects the Andaman Sea spreading center in the south with the Himalayan continental collision zone to the north. Modern GPS measurements show the two sides of the fault are slipping past each other at a rate of approximately 18 to 20 millimeters per year. This constant, slow movement builds up strain that is released in periodic earthquakes. The fault passes directly through some of Myanmar's most populated areas, including the cities of Sagaing, Mandalay, and the nation's capital, Naypyidaw.
The fault's geomorphology is visible on the landscape. It creates linear valleys, fault scarps, and offset stream channels. In some locations, streams have been displaced laterally by as much as 2.4 kilometers over time. The total displacement along the fault since its inception is estimated to be between 360 and 400 kilometers. The fault is not a single, simple line but has several segments. For instance, the Naypyidaw segment consists of two parallel fault traces running for about 70 kilometers directly beneath the capital city.