Articles | Volume 372
12 Nov 2015
 | 12 Nov 2015

Regional subsidence modelling in Murcia city (SE Spain) using 1-D vertical finite element analysis and 2-D interpolation of ground surface displacements

S. Tessitore, J. A. Fernández-Merodo, G. Herrera, R. Tomás, M. Ramondini, M. Sanabria, J. Duro, J. Mulas, and D. Calcaterra

Abstract. Subsidence is a hazard that may have natural or anthropogenic origin causing important economic losses. The area of Murcia city (SE Spain) has been affected by subsidence due to groundwater overexploitation since the year 1992. The main observed historical piezometric level declines occurred in the periods 1982–1984, 1992–1995 and 2004–2008 and showed a close correlation with the temporal evolution of ground displacements. Since 2008, the pressure recovery in the aquifer has led to an uplift of the ground surface that has been detected by the extensometers. In the present work an elastic hydro-mechanical finite element code has been used to compute the subsidence time series for 24 geotechnical boreholes, prescribing the measured groundwater table evolution. The achieved results have been compared with the displacements estimated through an advanced DInSAR technique and measured by the extensometers. These spatio-temporal comparisons have showed that, in spite of the limited geomechanical data available, the model has turned out to satisfactorily reproduce the subsidence phenomenon affecting Murcia City. The model will allow the prediction of future induced deformations and the consequences of any piezometric level variation in the study area.

Short summary
The implementation of FEM models permits to effectively analyse the cause-effect mechanism of a phenomenon.In the present work, in spite of the limited geotechnical and hydrogeological data available, the model has allowed to qualitatively and “quantitatively” reproduce the subsidence that affects Murcia city. The achieved results have been compared with the displacements estimated through A-DInSAR techniques and measured by the extensometers.This allows a better management of the exploitations.