Main Himalayan Thrust Imaging Beneath the Bhutan Himalaya: Evidence from Multiscale Surface Wave Tomography
The Research group of Dr. Ashwani Kant Tiwari [Department of Earth and Environmental Sciences] developed “a three-dimensional shear-wave velocity structure of the Bhutan Himalaya to 50 km depth by integrating ambient noise and teleseismic surface wave dispersion. The Bhutan Himalaya, located within the India-Eurasia collision zone, is characterized by active deformation and poses significant seismic hazards. The resulting model provides the first laterally continuous image of the Main Himalayan Thrust (MHT) across Bhutan, revealing pronounced along-strike variations in its geometry and segmentation. The MHT is imaged as a laterally continuous low-velocity layer (LVL) exhibiting a flat-ramp geometry: in western Bhutan a ramp emerges at approx. 10 km, whereas in eastern Bhutan, the structure dips more gently to approx. 20 km. In central Bhutan, disruption of the LVL, together with a concave-upward lower-crustal anomaly, suggest possible tear or segmentation of the thrust system. These features have important implications for how large earthquakes may rupture in Bhutan.”For more details, kindly visit https://doi.org/10.1029/2025JB033084
