1D and quasi-2D joint inversion of TDEM and DCR data to evaluate seawater intrusion in coastal areas: a case of study in Algarve (South of Portugal)
- F. J. Martínez Moreno
- F.A. Monteiro-Santos
- I. Bernardo
- M. Farzamian
- C. Nascimento
- J. Fernandes
- B. Casal
- J.A. Ribeiro
Editorial: Editorial Universidad de Granada
ISBN: 978-84-338-6152-8
Año de publicación: 2017
Páginas: 333-338
Tipo: Capítulo de Libro
Resumen
Seawater intrusion is caused by sea-level rise, extreme phenomena like flooding and droughts, and overpumping near to the coastal line. Geophysical methods are the most appropriate tools to evaluate the seawater intrusion in a specific area. Electrical methods are able to detect seawater intrusions due to the high resistivity contrast between salt or freshwater and geological layers. Combining several methods is the most recommended and efficient way since both data are inverted jointly. The final model encompasses physical properties measured for each method. This study analyse seawater intrusion in an area within the Ferragudo-Albufeira aquifer system (Algarve, S Portugal). For this purpose a single profile combining direct current resistivity (DCR) and time domain electromagnetic (TDEM) methods was measured and compared with information from a drill performed near to the profiles. Three different inversion algorithms have been carried out: single inversion, 1D and quasi-2D joint inversion lateral constrained of the DCR and TDEM data. Single inversion shows seawater intrusion, although the sedimentary layers detected in the drill are not well differentiated. 1D-joint inversion improves the previous one due to more sedimentary layer are detected and the seawater intrusion is better highlighted. Finally, the quasi–2D inversion exposes a more fitted shape for the seawater intrusion and it is able to distinguish more sedimentary layer. This study demonstrate that the novelty in quasi–2D joint inversion technique improves the previous standard inversions methods in the detection of seawater intrusion.