Mapping and Monitoring to Spatial-Temporal Evolution of Land Subsidence Using DInSAR Method
Abstract
Monitoring of subsidence of the land surface provides information that can be used in flood
control, ground-water extraction regulation, spatial planning, infrastructure design, and
construction especially in urban areas such as Kampala. Traditionally, urban subsidence has been
monitored using Global Positioning System (GPS), leveling, hydrogeology methods, e.g. ground
water level observation, extensometer measurement and piezometer measurement. Although the
techniques provide reliable and accurate measurements, they are expensive and don’t provide
sufficient samples required for land subsidence mapping. This research explored the use of
Differential Interferometric Synthetic Aperture Radar (DInSAR) approach for mapping and
monitoring the spatial-temporal evolution of land subsidence over Kampala-central region.
This was implemented by measuring the change in phase of Sentinel-1A single look complex
images acquired between 2014 and 2020. Displacement estimates varied between -0.066m to
+0.062m while the mean displacements varied between -0.021m to 0.005m. High surface
displacement was detected in the central region of the study area. In general, analysis of sentinel 1A data using DInSAR approach provides a worthwhile option for mapping and monitoring the
spatial-temporal evolution of land subsidence over Kampala-Central division