GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.2 GNGTS 2023 structures, whose absorption signature is likely caused by hot hydrothermal fluids stored within the first 2 km of the crust (Geyer et al., 2019; Luzon et al., 2011). The spatial correlations support the inference that the highest-absorption anomaly in the northern bay represents the top of a high-temperature reservoir, appearing as the primary source for the recent eruptions of the volcano. The NNW-SSE-striking highest-absorption anomaly in the eastern part of the bay shows a strong spatial correlation with the minimum magnetic anomaly found by Catalan et al. (2014) and Funaki et al. (2014) (Figure 2a, while lines). The magnetic maxima are instead parallel to and located NE of the Ba1 low-absorption feature (Figure 2a, black oval) and interpreted by Catalan et al. (2014) and Funaki et al. (2014) as a cooled magmatic body. The morpho-tectonic zoning projected on the cartographic traces carried out by Paredes et al. (2006) highlights the most superficial elements across the island. This study recognizes three zones (Figure 2b): the three high-absorption anomalies (Aa1-Aa3) fall within or are at the border of areas marked by the gray, mixed-deformation zone (Figure 2b), an expression of deep processes and high fumarole activity. Fig 1: (a) Absorption maps at different frequencies and node spacings. High absorption: Aa1—Pendulum Cove area; Aa2—Fumarole Bay; Aa3—Entrance Point. Low absorption: Ba1—Mount Pond; Ba2—Mount Kirkwood. The continuous white lines show the primary absorption trends, while dashed lines contour and zoom on of their crossing point at 2 km node spacing. (b) The absorption maps of Prudencio et al. (2013) and (c) the velocity tomography of Zandomeneghi et al. (2009) are reproduced with the same colorscale for comparison.