Abstract
Abstract. Subsidence is a natural hazard that affects wide areas in the world causing important economic costs annually. This phenomenon has occurred in the metropolitan area of Murcia City (SE Spain) as a result of groundwater overexploitation. In this work aquifer system subsidence is investigated using an advanced differential SAR interferometry remote sensing technique (A-DInSAR) called Stable Point Network (SPN). The SPN derived displacement results, mainly the velocity displacement maps and the time series of the displacement, reveal that in the period 2004–2008 the rate of subsidence in Murcia metropolitan area doubled with respect to the previous period from 1995 to 2005. The acceleration of the deformation phenomenon is explained by the drought period started in 2006. The comparison of the temporal evolution of the displacements measured with the extensometers and the SPN technique shows an average absolute error of 3.9±3.8 mm. Finally, results from a finite element model developed to simulate the recorded time history subsidence from known water table height changes compares well with the SPN displacement time series estimations. This result demonstrates the potential of A-DInSAR techniques to validate subsidence prediction models as an alternative to using instrumental ground based techniques for validation.
Highlights
Ground subsidence is a natural hazard that affects wide areas causing important economic damages and a high social alarm
The acceleration of the deformation phenomenon is explained by the drought period started in 2006
The comparison of the temporal evolution of the displacements measured with the extensometers and the Stable Point Network (SPN) technique shows an average absolute error of 3.9±3.8 mm
Summary
Differential Interferometry with Synthetic Aperture Radar (DInSAR) has become over the last decade an important remote sensing tool for the estimation of the temporal evolution of ground surface displacements. The temporal evolution of the subsidence in Murcia city has been monitored by an extensometer network since 2001 (Mulas et al, 2001, 2005; Peral et al, 2002), and since 1975 groundwater table variations (Aragon et al, 2004) have been recorded through a spatially dense piezometric network. This phenomenon has been analysed through the application of different Advanced DInSAR techniques in previous works (Mulas et al, 2004; Tomas et al, 2005; Herrera et al, 2008). Results are compared and validated with the extensometer and SPN displacement time series estimations
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