Analysis of Heterogeneous PS-InSAR Derived Subsidence Rates Using Categorized GIS Objects - A Case Study in the Mekong Delta

Land subsidence in urban areas is frequently characterized by high spatial heterogeneity, caused by variability in the local lithology, land-use history as well as different load and foundation depths of infrastructure. This effect can, for example, be observed in the Mekong Delta, which is subsiding on large scale with rates up to several centimeters per year. We estimated subsidence rates using PS-InSAR and systematically analyzed differential subsidence between bridges, which are usually built with pile foundations, and the surrounding land surface. We used GIS information on bridge locations from OpenStreetMap and automatically determined the differential subsidence rates at these GIS objects on a delta-wide scale. We show that most of the considered bridges are affected by lower subsidence rates than their surroundings. These results can help in future studies to constrain the depth of soil compaction and better understand the drivers of land subsidence.