First geodetic mission for PAMELi on the slopes of Mount Etna to study the deformation of an underwater fault by combining GNSS and underwater acoustic signals (GNSS/A). This mission, FOCUS-G1, in which Thibault Coulombier and Denis Dausse took part, is being carried out on the N/O Tethys in collaboration with the LGO Brest, in the framework of the ERC FOCUS.