Gravimetric investigation of the structure of the Etna summit craters system

New gravimetric observations were carried out in the summit area of Mt. Etna in July 2021. Only the north-west half of the planned survey area was accessible to field work due to ongoing intense eruptive activity. The new gravimetric observation points (171 in number) were positioned using precise geodetic positioning based on GNSS technology. Due to rough conditions, unstable ground and wind, the gravity observations were collected with a precision of about 15 microGal using two relative gravimeters (CG5 and CG6). Complete Bouguer anomalies (CBA) were compiled. The computation of accurate topographic correction for CBA compilation poses a challenge because of the ever-changing topography around the summit craters due to intense eruptive activity. Precise topographic correction was computed using the Toposk software. The available high resolution (5 m) DEM released in 2016, and the reference constant topographic density of 2300 kg/m3, which resulted from our analysis as representative for the summit area, were adopted for the numerical evaluation of the topographic correction. These data will serve the 2D and 3D density modelling for determining the subsurface structural model of the summit area and the upper-most part of magma feeders of the summit craters on Etna.