3D electrical imaging of the inner structure of a complex lava dome, Puy de Dôme volcano (French Massif Central, France)

Abstract

Lava domes result from extrusion of massive lava, frequent explosions and collapses. This contribution focuses on a complex trachytic lava dome, the Puy de Dôme volcano, located in the Chaîne des Puys volcanic field (French Massif Central, France). We performed Electrical Resistivity Tomography (ERT) acquisitions on the entire edifice in order to investigate its overall inner structure as well as to detail its summit area. The resulting large ERT dataset integrated a recently developed 3D inversion code based on an unstructured discretization of the geometrical model. The 3D inversion models obtained refine the existing geological model of the Puy de Dôme's inner structure obtained by previous geophysical studies. These results also highlight the strong fracturing and fumarolic alteration that affect the summit part of the volcano.