Displacement field in Lorca (Murcia, Spain) subsidence area: Observation and modeling
Abstract
The Lorca area, Alto Guadalentín Basin, located in southern Spain, is affected by the highest subsidence rates measured in Europe (about 10 cm/yr) produced by a long-term aquifer exploitation (González and Fernández, 2011). This subsidence has been studied using satellite radar interferometry (InSAR) using images from different satellites (ERS and ENVISAT radar data spanning the 1992 - 2007 period; ALOS PALSAR data for the period 2007-2010; and COSMO-SkyMed data for the period 2011-2012). González et al. (2012) found a relationship between the crust unloading produced by the groundwater overexploitation and the stress change on the regional active tectonic faults in relation with the May 2008 Lorca earthquake. The InSAR results have been compared with measurements acquired by two permanent GNSS stations located in the study area, and with geological and hydrogeological data collected and analyzed in order to assess aquifer system compressibility and groundwater level changes in the past 50 years. All the previous studies of the area were based on satellite radar interferometry using just ascending or descending acquisitions, without any combination among them, to obtain vertical and horizontal (E-W) components. However, it is important to obtain the 3D motion field in order to perform a correct interpretation of the observations, as well as to carry out an advanced numerical model of the aquifer evolution, to be consider for sustainable management plans of groundwater resources and hazard assessments. To solve this problem, we defined a GNSS network, and various surveys have been carried out, from November 2015, showing the regional 3D displacement field associated to the exploitation of the aquifer. GNSS and InSAR results has been compared, obtaining a good agreement. We present the results obtained from both techniques, the comparison between them, and interpretation results using different inversion techniques. REFERENCESGonzález, P.J., Fernández, J., 2011. Geology, 39/6, 551-554; doi: 10.1130/G31900.1.González, P.J.; et al., 2012. Nature Geoscience, 5/11, 755-834. doi: 10.1038/NGEO1610.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMNH32A..03F
- Keywords:
-
- 1209 Tectonic deformation;
- GEODESY AND GRAVITY;
- 1812 Drought;
- HYDROLOGY;
- 4302 Geological;
- NATURAL HAZARDS;
- 4303 Hydrological;
- NATURAL HAZARDS