Puig d’Àdri is a complex volcano in the Garrotxa Volcanic Field (0.7–0.01 Ma), the youngest part of the Catalan Volcanic Zone (NE Iberian Peninsula). The construction of this volcano involved the superimposition of three volcanic edifices with five lithostratigraphic units, in which several Strombolian and phreatomagmatic episodes alternated. Geological and geophysical surveys performed using electrical resistivity tomography and self-potential have contributed to revealing the internal structure of the volcano and the succession of deposits. The ring–cone morphology of the phreatomagmatic part of the structure shows how a number of variables including the way in which magma and water interacted greatly influenced the eruptive dynamics and the mechanisms of formation. A further major issue reflected in the final structure of the edifice is the process of vent migration, which was controlled by the characteristics of the substrate and its interaction with the magma as it rose.
Supplementary material: Granulometric and component histograms of the samples not shown in Figure 4 are available at http://doi.org/10.6084/m9.figshare.c.3262498