The evolution of volcanic edifices is the result of the interplay of several types of constructive and destructive processes. We approach the study of this evolution by means of the combination of remote sensing, geological fieldwork and petrological-geochemical studies (including radiometric dating) integrating those multiple data sets using Geographic Information Systems (GIS). We are interested both in the volcanological and structural histories of the volcanoes, combining therefore the mapping of volcanic units and structures (e.g., dykes) with their sampling for laboratory work. Our current fieldwork is focussed in Canary Islands, mainly at volcanic edifices of Tenerife and La Gomera. We perform part of this geological work inside the galleries drilled there for groundwater extraction, obtaining an unusual data set of geological structures at 3D inside the volcanic edifices.