GNGTS 2022 - Atti del 40° Convegno Nazionale

GNGTS 2022 Sessione 1.2 117 gradual thinning of the loose deposit at the foot of the slope, which completely disappears moving upwards (see elevation lines in the background). Moving southwards, the negative values reach the minimum roughly in correspondence of the anomaly suggested by Bruno and Castiello (2009) (Fig. 1). This trend is clearly recognizable in the section shown in Fig. 3 (see Fig.1 for the location) which extends even more southeastwards with respect the area displayed in Fig. 2. More to the south, the value of the total magnetic field increases and becomes positive. Again, this is in agreement with the other magnetic investigations previously mentioned. The map of the vertical gradient (Fig. 2) shows several small-scale peaks (either negative and positive), with wavelengths in the order of some tens of meters. They are especially concentrated in the southernmost part of the surveyed area and recognizable also in the section (Fig. 3). They appear as bipolar anomalies, with adjacent positive and negative peaks and could be the result of some near-surface features. The results coming from the other geophysical technique will represent the base for the modelling of the magnetic data. Moreover, the integration of all the available information will provide a robust interpretation of this key area of Vulcano Island. Fig. 3 - Filtered magnetic profile (40 samples running average) showing both the total field and the vertical gradient. See Fig. 1 for the location. Acknowledgements. The authors thank Vincenzo Sapia (Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2) who provided the magnetometer and supported the field activities. References Alparone S., Bonforte A., Gambino S., Guglielmino F., Obrizzo F. and Velardita R.; 2019: Dynamics of Vulcano Island (Tyrrhenian Sea, Italy) investigated by long-term (40 years) geophysical data . Earth-Sci. Rev., 190, 521-535. Alparone S., Cannata A., Gambino S., Gresta S., Milluzzo, V. and Montalto P.; 2010: Time-space variation of volcano- seismic events at La Fossa (Vulcano, Aeolian Islands, Italy): new insights into seismic sources in a hydrothermal system. Bull. Volcanol., 72(7), 803-816. Barberi F., Gandino A., Gioncada A., La Torre P., Sbrana A. and Zenucchini C.; 1994: The deep structure of the Eolian arc (Filicudi-Panarea-Vulcano sector) in light of gravity, magnetic and volcanological data . J. Volcanol. Geotherm. Res., 61(3-4), 189-206. Barreca G., Bruno V., Cultrera F., Mattia M., Monaco C. and Scarfì, L.; 2014: New insights in the geodynamics of the Lipari–Vulcano area (Aeolian Archipelago, southern Italy) from geological, geodetic and seismological data . Journal Geodyn., 82, 150-167. Barde-Cabusson S., Finizola A., Revil A., Ricci T., Piscitelli S., Rizzo E., Angeletti B., Balasco M., Bennati L., Byrdina S., Carzaniga N., Crespy A., Di Gangi F., Morin J., Perrone A., Rossi M., Roulleau E., Suski B. and Villeneuve N.; 2009: New geological insights and structural control on fluid circulation in La Fossa cone (Vulcano, Aeolian Islands, Italy) . J. Volcanol. Geotherm. Res., 185(3), 231-245. Blanco-Montenegro I., de Ritis R. and Chiappini M.; 2007: Imaging and modelling the subsurface structure of volcanic calderaswith high-resolution aeromagnetic data at Vulcano (Aeolian Islands, Italy). Bull. Volcanol., 69, 643-659, DOI 10.1007/ s00445-006-0100-7.