Ground subsidence monitoring in India using InSAR: A review of current status and future prospects

This review provides a brief overview of various types of synthetic aperture radar (SAR) techniques, their working mechanisms and applicability to detect ground subsidence. It addresses the development of advanced remote sensing techniques and algorithms for accurately determining subsidence rates. Ground subsidence is one of the major factors that has raised serious concerns globally, particularly for urban planning and infrastructure development. On a global scale, the study of ground subsidence with the aid of ground and RADAR-based geodetic techniques is growing rapidly. The SAR technique is used to monitor ground subsidence across different zones of India viz. the eastern, northeastern, northern, southern, western, and central zones. By synthesising the published records, this review provides the key research gaps and potential future directions for effective and widespread adaptation of InSAR-based studies in India. Future research may explore the integration of several data sources, including satellite and ground-based geodetic data, alongside the estimation of subsurface deformation rates, to provide a more comprehensive understanding of the subsidence mechanism. Future studies will focus on finding the elements that cause ground subsidence at finer local and regional scales, specifically in mountainous, desert, and rural areas. Moreover, we would like to highlight that the InSAR technique might be useful for monitoring glacier loading and unloading velocities, together with alterations included by regional tectonic deformation.