Abstract

The full magnetotelluric (MT) spectrum, ranging from passive MT to Radio-MT (RMT) - passive and controlled-source, provides a powerful framework for imaging fluid- and melt-related structures in tectonically and volcanically active regions. Case studies from the Eger Rift and the Eastern Eifel volcanic field (Laacher See area) demonstrate how combined deep and shallow EM data resolve multiscale fluid pathways linking the lower crust to near-surface degassing and aquifer systems. Particular emphasis is placed on advanced data processing strategies required to mitigate strong anthropogenic electromagnetic noise. The approach is further extended to the Chilean Coastal Cordillera, where active RMT measurements using a magnetic transmitter highlight the potential of controlled-source EM techniques for high-resolution shallow imaging in the context of Earth Surface processes.