f Recent advances in engineering geophysics Spectral IP and Multifrequency EM

There are two main needs to improve the usability of geophysical methods for geotechnical and environmental investigations: the speed has to be increased to optimize costs and better correlation is needed between geophysical results and true subsurface parameters. Two methods - multifrequency EM and Spectral IP - are presented. None of them is entirely new, but they are going to be used in practise now. Measurements from different sites are shown.