A ground subsidence study based on DInSAR data: calibration of soil parameters and subsidence prediction in Murcia City (Spain)

Abstract

Subsidence is a hazard that affects wide areas in the world causing important economic costs annually. The City of Murcia (SE Spain) is affected by this phenomenon since the 90s. In this work, ground subsidence caused by aquifer overexploitation is remotely monitored with Persistent Scatterer Interferometry (PSI). In particular, the so-called Coherent Pixels Technique (CPT) has been applied to SAR images from ERS and ENVISAT satellites. The CPT displacement time series corresponding to the 1993–1995 period have been used to calibrate a proposed one-dimensional subsidence model. Hence, the CPT time series have been successfully used to retrieve physical parameters of the soil. Then the model has been used to predict the deformations for the period 1993–2007. The comparison between the predictions of the model and the actual subsidence time series for the 1995–2007 period provides an average absolute difference of 3.2 ± 2.5 mm. Despite the simplicity of the adopted 1D model, these results show the usefulness of the CPT derived displacement information to calibrate and validate numerical models of ground subsidence due to aquifer overexploitation, which can be used to predict the aquifer's response for future piezometric falls.