Comparison of Electrical Resistivity Tomography and Frequency Domain Electromagnetic Methods for Mapping Seawater Intrusion in Shallow Aquifers

This dataset supports a comparative geophysical study of seawater intrusion in shallow coastal aquifers using Electrical Resistivity Tomography (ERT) and two Frequency Domain Electromagnetic (FDEM) instruments: GEM-2 (multi-frequency, variable induction number) and CMD Explorer (multi-offset, constant frequency, constant induction number). The study was conducted at four test sites near the Grado Lagoon in Northeastern Italy—called Belvedere, Tiel, Duna, and Fossalon—chosen for their varying hydrological, morphological, and salinity characteristics. At each site, apparent electrical conductivity (ECa) measurements were collected with both FDEM instruments and benchmarked against ERT survey results through statistical cross-correlation. Calibration equations derived from the regression analysis were used to normalize the FDEM datasets. Borehole data were also used for validation. The dataset includes: Raw ECa data from ERT, GEM-2 and CMD Explorer instruments (.xlsx, .csv, .dat formats) for each test site A MATLAB script (CROSS_PLOTS.m) used for statistical cross-correlation and calibration between FDEM and ERT datasets Areal coverage of test site TIEL to evaluate the scalability and performance of calibration techniques for regional-scale salinity mapping. This study was funded by the European Union - NextGenerationEU, in the framework of the iNEST - Interconnected Nord-Est Innovation Ecosystem (iNEST ECS00000043 – CUP J43C22000320006). The views and opinions expressed are solely those of the authors and do not necessarily reflect those of the European Union, nor can the European Union be held responsible for them. The dataset was developed as part of the activities carried out by Spoke 8, Research Topic 2 (Physical chemical risks and impact on the hydrosphere), Task S3_4 (Risks and impacts on the coastal zone due to episodic events and sea-level rise).