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Abstract:
The elastic strength of the lithosphere is commonly described by its effective elastic thickness (Te). Therefore, estimation of Te is essential in determining how the lithosphere may respond to loads related to tectonic processes. It is usually estimated either by forward/inverse modeling of gravity and topography or by thermo-rheological modeling. However, over the continental lithosphere, significant ambiguities exist in the Te estimates because of anomalies in the rheology, Bouguer gravity, brittle-ductile transition depth, etc. As a result, two opposing models addressing the distribution of elastic strength within the continental lithosphere emerged. According to the model known as the ‘Jelly sandwich,’ the mechanical strength of the lithosphere is distributed in the upper crust and the lithospheric mantle. According to the ‘Crème Brulee’ model, the lithospheric mantle is weak, and the mechanical strength of the lithosphere is limited to the upper crust. Joint modeling of seismological and gravity observations has recently gained prominence in this regime as they can provide better-constrained estimates of continental Te. We introduce joint modeling of Bouguer anomaly and topographic data along with teleseismic travel time residuals to delineate the lithosphere’s structural and elastic strength variation. We employed this new methodology to decipher the effective elastic thickness of the lithosphere and ascertain the contribution of the crust and the lithospheric mantle toward compensating for the topographic load over both active and passive regions of the Indian continental lithosphere.
