Main Boundary Thrust

The Main Boundary Thrust (MBT), also known as the Main Boundary Fault, is a discontinuous series of seismic faults in the Himalayas which form the structural boundary between the Outer Himalayas and Lower Himalayan Range. The MBT is itself part of a series of thrusts which helped to accommodate the deformation when the Indian Plate collided with the Eurasian Plate in the Cenozoic. The MBT fault system began forming in the Miocene. The MBT consists of multiple segments, and is composed from west to east of the Murree and Drang thrust faults, the Krol thrust fault, the Surkhet-Ghorahi thrust fault, the Kathmandu thrust, and the Gondwana/Garu thrust. Despite originating as a thrust fault in the collision of India and Eurasia, the MBT system has reactivated as a normal faulting system.