India‐Sunda Plate Motion, Crustal Deformation, and Seismic Hazard in the Indo‐Burmese Arc

Plate motion along the Indo-Burmese Arc (IBA), strain accommodation in the Indo-Burmese wedge, status of active convergence and seismic vulnerability in the outer wedge, is a matter of concern due to the large population density in northeast India, Bangladesh, and Myanmar. In the present study, we have constrained the India-Sunda plate motion by estimating the Euler pole using updated GPS observations from the region. Our estimated India-Sunda relative plate motion at a point on the blind megathrust (24°N and 90°E) in Bangladesh constrains India-Sunda relative motion at ~37 mm/year oriented along N11°E. This motion is partitioned among three major active units, namely, the Sagaing Fault (~18 mm/year), Churachandpur-Mao Fault (~17 mm/year), and the blind megathrust (~7 mm/year), from west to east of the IBA, respectively. Our estimate of convergence across the blind megathrust is significantly lower than that estimated earlier. Due to large scatter in the data close to the updip edge of the blind megathrust, it is not certain whether it is accommodated through shallow creep or in stick-slip manner, thus leading to uncertainty in the seismic hazard in this densely populated region.