Following the closure of the Neo-Tethys ocean, the Indian plate began to collide with the Eurasian plate in the Eocene (e.g., Molnar & Stock, 2009). One of the profound consequences is the formation of the Himalayan mountain belt and the Tibetan plateau. The convergent boundary extends along the Himalayan arc and is terminated to the east at the eastern Himalayan syntaxis, where it bends to the south, continues along the Burma arc, and connects to the Andaman-Sumatra arc, a site of oceanic subduction. While many seismic experiments have demonstrated that the Indian lithosphere is underthrusting northwards under Tibet (e.g., Kind et al., 2002; Nábělek et al., 2009), the detailed subduction geometry