Land subsidence hazards in Hanoi, Vietnam

The study area is located in the southwest of Hanoi, the capital of Vietnam, encompassing the districts of Quoc Oai, Chuong My, My Duc, and Ung Hoa. This region is densely populated and has experienced frequent collapses and land subsidence over the years. Notably, these phenomena have persisted into 2023. The foundation structures in the southwestern part of Hanoi are categorized into five types, with Quaternary sediments forming the upper layer and limestone constituting the base. The formation of Quaternary sediments over the Dong Giao Formation limestone is closely linked to the transgressive and regressive processes that occurred during the Quaternary period. Based on geological research, geophysical studies, and wellbore analysis, the authors have drawn the following conclusions: 1. The collapses are associated with underground karst activity, and 2. Urbanization and underground exploitation are key factors contributing to the increasing frequency of collapses. These research findings are scientifically significant and serve as a valuable resource for identifying and warning about geohazards in areas with similar geological conditions. They also support efforts toward achieving the Sustainable Development Goals.