Ebro Delta Geometry and Structure Characterization Using the Electrical Resistivity Imaging Method
F. Bellmunt, A. Gabàs, A. Macau, B. Benjumea and S. Figueras
Event name: 24th European Meeting of Environmental and Engineering Geophysics
Session: Geophysics in Engineering Geology and Geotechnical A
Publication date: 09 September 2018
Info: Extended abstract, PDF ( 532.26Kb )
Price: € 20
The Ebro Delta is currently a place of interest due to the presence of zones vulnerable to subsidence. Determining the type of sediment that favours the subsidence and its identification in the subsoil is a critical task for planning protection actions in the Ebro Delta. In this point the geophysical methods can help providing subsoil information. The subsidence mainly relies on Holocene sediments (clays, silts, sands and organic deposits). All these materials are affected by salty, fresh or brackish water. For this reason, one of the best geophysical techniques to describe the geometrical structure of complex lithologies, and its spatial variation, is the electrical resistivity tomography (ERT). The used geophysical parameter is really sensitivity to the presence of ions, and efficiently detects fresh water and saline water zones. The application of ten ERT long profiles (355 m - 1km) distributed around the studied area are a well-suited way to study the different environments inside the delta and to understand its evolution, from coast to margin side. In addition, the established geoelectrical boundaries have been used as a reference to build the 3D geological model surfaces, which will be used to assess the subsidence of the whole delta plain.