Intraplate stress distribution within the Indian Plate: Insights from finite element modelling

Abstract

The Indian Plate is bounded by different types of plate boundaries like divergent, convergent/collisional, transform and consists of oceanic and continental lithosphere. Due to such tectonic settings, the intraplate tectonic stress distribution across the Indian Plate is very complex. Further, available in-situ stress information over the Indian Plate is relatively sparse; therefore, numerical modelling of maximum horizontal compressive stress (SHmax) is needed to comprehend regional stress patterns. In the present work, stress simulations are carried out to explore the effects of rigidity, lithospheric thickness, and boundary forces on the distribution of intraplate stress across the Indian Plate. The rigidity is derived from effective elastic plate thickness (Te), which is estimated through joint inversion of admittance and coherence using the wavelet transform approach. The stress field is simulated for four cases for different combinations of Te, lithospheric thickness and tectonic forces and compared with in-situ stress observations. The analysis of models shows that the magnitude of SHmax is primarily controlled by boundary forces, Te and scaled by lithospheric thickness; and its orientations are mostly governed by the applied tectonic forces and rigidity. Spatial distribution of earthquakes correlated well with the von-Mises stress and high von-Mises stresses are accumulated at earthquake prone regions. The stress field and von-Mises stress over major geological features are also analyzed and discussed. Apart from boundary forces, it is inferred that Te is one of the most significant factors which controls the stress field distribution.