Research Projects

Despite the tectonic and seismogenic significance of the Northwest Himalaya, the region remains underexplored due to logistical constraints. While numerous studies have elucidated shallow crustal deformation, the seismic structure of shear wave velocity contrast across the Moho (δβM) remains inadequately constrained. Consequently, the detailed study regarding the crustal low-velocity zone (LVZ) is not well resolved. Furthermore, the potential relationship between LVL and the distribution of regional seismicity has received limited attention in existing studies. Recent seismic observations suggest the existence and geometry of intra-crustal LVZs, possibly indicative of weak, hydrated, or partially molten crustal materials, may provide critical information about crustal strength, seismicity, and long-term tectonic deformation. One of the most direct geophysical proxies for detecting all these features is δβM. In particular, the δβM, a key diagnostic of crust-mantle mechanical coupling, lower crustal rheology, and crustal LVZs, which may reflect partial melt or fluid accumulation, influencing earthquake generation, has not been investigated in the North-West Himalaya. However, such insights remain largely unexplored in the context of the Northwest Himalaya. In addition to crustal imaging, the mantle transition zone (MTZ), bounded by the 410 km and 660 km seismic discontinuities, is highly sensitive to variations in temperature, composition, and hydration. Imaging the topography and sharpness of these discontinuities beneath the Himalaya allows for the assessment of slab penetration depth, thermal anomalies, and potential stagnation of the subducting Indian lithosphere within the MTZ. Deviations in the depth or amplitude of these discontinuities can also signal hydration-induced buoyancy or compositional heterogeneities, which may exert significant influence on mantle convection and surface tectonics. With these motivations, the primary objectives of this proposal are: • To estimate, for the first time, the image of δβM and its lateral variability beneath the Northwest Himalaya, using a modified receiver function technique integrated with newly developed analysis tools. • To delineate the crustal low-velocity zone (LVZ) and investigate its correlation with regional seismicity. • To image the MTZ beneath the Northwest Himalaya, with a focus on resolving the 410 km and 660 km discontinuities. To achieve these objectives, the study will utilize P- and S-receiver function analysis, waveform inversion, and Common Conversion Point (CCP) migration. A recently developed computational tool will be employed to estimate the δβM. Ultimately, the proposed work aims to advance our understanding of the seismotectonic architecture of the Northwest Himalaya by elucidating the roles of Moho properties, intra-crustal LVZs, and upper mantle discontinuities in accommodating crustal deformation and localizing seismicity.