Cross-section electrical resistance tomography of La Soufrière of Guadeloupe lava dome

SUMMARY The electrical resistivity distribution at the base of La Soufriof Guadeloupe lava dome is reconstructed by using transmission electrical resistivity data obtained by injecting an elec- trical current between two electrodes located on opposite sides of the volcano. Several pairs of injection electrodes are used in order to constitute a data set spanning the whole range of azimuths, and the electrical potential is measured along a cable covering an angular sector of ≈120 ◦ alongthebasisofthedome.Thedataareinvertedtoperformasliceelectricalresistivity tomography (SERT) with specific functions implemented in the EIDORS open source package dedicated to electrical impedance tomography applied to medicine and geophysics. The result- ing image shows the presence of highly conductive regions separated by resistive ridges. The conductive regions correspond to unconsolidated material saturated by hydrothermal fluids. Two of them are associated with partial flank collapses and may represent large reservoirs that could have played an important role during past eruptive events. The resistive ridges may represent massive andesite and are expected to constitute hydraulic barriers.