Satellite Data Reveals Ground Subsidence in Multiple Global Cities

A comprehensive study utilizing high-resolution satellite data from 2014 to 2023 has identified widespread ground subsidence affecting 465 cities across 107 countries. Published in Nature Cities, the research highlights the extent of a phenomenon that can damage infrastructure and increase flood risks. Ground subsidence, the gradual sinking of the Earth's surface, poses significant threats to urban environments. The study, led by researchers including Shengli Tao and Xie Hu, found localized subsidence rates as high as 217 millimeters per year in parts of Mexico City, although the city's median rate was 8 millimeters per year. Torreón, also in Mexico, experienced subsidence of approximately 17 millimeters annually. Asia shows the most severe impacts, with Medan, Indonesia, experiencing a median subsidence of around 33 millimeters per year, followed by Bandung at 22 millimeters per year. Isfahan, Iran, also featured prominently with 11 millimeters per year. In contrast, cities such as Boston, New York, London, Beijing, Tokyo, and Sydney exhibited stable ground deformation, with estimated rates between 0.1 and 1.9 millimeters per year. The researchers caution that their nine-year study focused on relative subsidence within major cities and may not cover areas outside administrative boundaries. They emphasize that continuous monitoring is crucial to validate subsidence trends and inform targeted mitigation efforts.