Comparison of waterlevel, extensometric, DInSAR and simulation data for quantification of subsidence in Murcia City (SE Spain)
Tessitore Serena1,2,3, Fernández-Merodo Josè A.2,4,5, Herrera Gerardo2,4,5 , Tomás Roberto2,4,5,6, Ramondini Massimo3, Sanabria Margarita2,4,5 , Duro Javier7, Mulas Joaquín2,4,5 ,Calcaterra Domenico1.
1 Dipartimento di Scienze della Terra, dell’Ambiente e delle Risorse, Università degli Studi di Napoli Federico II, Largo San Marcellino 10, 80138 Napoli, Italy
2 Geohazards InSAR laboratory (InSARlab). Geoscience Research Department, Geological Survey of Spain (IGME), C/. Alenza 1,28003 Madrid, Spain
3 Dipartimento di Ingegneria Civile, Edile e Ambientale, Università degli Studi di Napoli Federico II, via Claudio 21, 80125 Naples, Italy
4 Grupo español de trabajo en subsidencia del terreno (SUBTER) de la UNESCO, Madrid, Spain
5 UNIRAD: Unidad Asociada de Interferometría Radar y Movimientos del Terreno de la Universidad de Alicante y el Instituto Geológico y Minero de España, Madrid, Spain
6 Departamento de Ingeniería Civil. Escuela Politécnica Superior, Universidad de Alicante, P.O. Box 99, E-03080 Alicante, Spain
7 Altamira Information, C/. Còrsega 381-387, 08037 Barcelona, Spain
Pages 1–21, 03 February 2016
Subsidence due to groundwater overexploitation has been recognized in the metropolitan area of Murcia (25 km2) in south-eastern Spain since the early 1990s. Previous published works have focused their attention on land subsidence that occurred during the drought period between 1995 and 2008. This work first analyzes the groundwater recovery that has occurred since 2008 and then determines the kind of associated ground deformation detected by the new extensometric data. Subsequently, subsidence time series are computed on 24 geotechnical boreholes scattered throughout the study area by means of a hydro-mechanical finite element code and a linear-elastic constitutive law. A spatio-temporal interpolation of the numerically modeled surface displacements is performed over the whole domain and compared with extensometers and DInSAR-derived displacement maps in two different periods: the drought period from 2004 to 2008, and the recovery period from 2008 to 2012. In spite of the limited information on the geomechanical parameters characterizing the modelled geological formations, the proposed approach is able to discriminate areas where the soils have an elastic behavior (small differences in the comparisons) or an elasto-plastic behavior (large differences in the comparisons). This zonation enhances the understanding of the subsidence phenomenon in Murcia City and could prevent, from a quantitatively point of view, future severe subsidence due to aquifer overexploitation.
Keywords: Subsidence; Numerical modeling; Aquifer exploitation; Geohazards; Spain
Published in the theme issue “Land Subsidence Processes”