Land subsidence detection using sentinel-1 interferometer and its relation with environmental drivers: a case study for coastal Mumbai city

The study presents a comprehensive analysis of land subsidence for Mumbai region, employing interferometric synthetic aperture radar, and analyzing groundwater measurements, GPS observations, and population growth data simultaneously. Sentinel-1 SAR imagery spanning October 2014 to May 2019 revealed irregular subsidence patterns with annual subsidence rate peaking at − 93 mm yr⁻¹ and a mean value of − 28 mm yr⁻¹. Spatial analysis identified high subsidence areas, including Byculla dockyard, Colaba, and Andheri East. Groundwater exploitation emerged as a significant cause, evidenced by spatial deformation patterns. Further, the study also explored shared socio-economic pathways (SSPs) scenarios of sea-level rise (SLR) and potential impact on coastal inundation in low-lying areas. Projections suggest that under the SSP5-8.5 emission scenario, potential regional SLR is expected to reach + 0.49, + 1.5, and + 2.5 m by 2050, 2100, and 2150, potentially expanding flood-prone areas by 6.649, 10.401, and 14.912% respectively. Population growth data revealed Mumbai’s consistent expansion, with projections indicating sustained growth despite fluctuations in the growth rates. Study emphasized the importance of addressing land subsidence and interconnected factors, such as groundwater depletion, and sea level rise (SLR), to mitigate coastal hazards and protect vulnerable populations.