Seismic Anisotropy and Splitting Intensity Beneath the South Indian Shield: Evidence for Archean Lithospheric Fabric and Post-Archean Deformation

We estimated shear-wave splitting parameters and splitting intensity using core-refracted phases (SKS and SKKS) recorded at 90 digital broadband seismic stations across the South Indian Shield, encompassing the Western Dharwar Craton (WDC), Eastern Dharwar Craton (EDC), and Southern Granulite Terrain (SGT). Observed delay times range from 0.4 to 1.5 s, with a mean of ~0.9 s, while fast polarization directions vary from NW to NE–NNE. Although delay times show no significant variation among the three tectonic domains, fast polarization directions exhibit pronounced spatial differences. The EDC is characterized predominantly by NE–NNE orientations, the WDC by N–S to NW directions, and the SGT by a mixed pattern ranging from NW to NE. The splitting intensity varies smoothly across the region, with values ranging from 0.8 to 1.0. These observations suggest that seismic anisotropy beneath the South Indian Shield reflects a complex interplay between the Archean lithospheric architecture and subsequent domain-specific deformation driven by deep Earth processes.