On Inversion of Frequency Domain Electromagnetic Data in Salt Water Problems - Sensitivity and Resolution

Frequency domain electromagnetics (FDEM) is a fast investigation method for large scales and can particularly be helpful in salt-water problems. Sensitivity studies and simple models show the dependence on geometric factors and noise levels. Methods of resolution analysis can be successfully applied to reveal uncertainties of the model parameters and interdependence of the data. A combination of electromagnetic and direct current data significantly improves the results and their reliability. The methods are demonstrated on synthetic data and field data from a coastal aquifer system.