Identifying Land Subsidence Using Global Digital Elevation Models

Recent developments in space-based surveying methods of the Earth's topography, including the differential interferometric synthetic aperture radar (DInSAR), have increased the availability of options for monitoring land subsidence. However, DInSAR methods require expert knowledge and specialized software, and they are time-consuming. Here, we demonstrate that a land subsidence signal can be identified in the differences in the freely available global digital elevation models (e.g., SRTM and TanDEM-X) using a simple statistical method. This finding opens up a venue to develop a computer application to identify land subsidence or uplift of a few decimeters per at least a decade order. Such an application enables monitoring the effects of underground mining, seismic/tectonic movements, landslides, volcanic activities, and similar effects on the Earth's topography. It can also provide a valuable and cost-effective tool for studying land deformation.