Geophysical research in subduction zones is based on bathymetric, seismic, magnetic, gravimetric measurement as well as numerical and analog modeling. Their combined interpretation leads to an image of the sub-surface and the dynamic processes related with subduction type and to estimate fluid and mass transfer within the subduction complex. The top of the subducting oceanic plate can be imaged seismically, which could have pracical implications for more precise earthquake hazard analysis in the areas investigate