Eruptive activity of individual monogenetic volcanoes usually lasts a few days or weeks. However, their short lifetime does not always mean that their dynamics and structure are simple. Monogenetic cones construction is rarely witnessed from the beginning to the end, and conditions for observing their internal structure are hardly reached. We provide high-resolution electrical resistivity sections (10m electrode spacing) of three monogenetic cones from northeastern Spain, comparing our results to geological observations to interpret their underground continuation. The 100m maximum depth of exploration provides information on almost the entire edifices, highlighting the relationships between Strombolian and hydromagmatic deposits in two multiphase edifices. A main observation is a column of distinct resistivity centered on the Puig d"Adri volcano, which we interpret as the eruptive conduit. This method can provide valuable information on the past volcanic dynamics of monogenetic volcanic fields, which has real implications for the forecast of future activity.