GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.2 - POSTER GNGTS 2023 An example of 2D resistivity section is reported in Fig. 2. Due to the strongly hydrothermalized environment, resistivity ranges between a few Ω m up to about 10000 Ω m, showing sharp contrasts, which are well consistent with the rock sequences inferred from the geological survey and the stratigraphic logs available in the neighbouring of the study area, and particularly with sequence of volcanic rocks deriving from debris flow mainly emplaced in relation to the resurgence of Mount Epomeo. Specifically, the lowest resistivity values (blue zones in Fig.2) are likely correlated to the occurrence of significant fluid circulation and/or highly fractured deposits, whilst the high resistive zones (red areas in Fig.2) are ascribable to the presence of a bedrock constituted of more cohesive tuffs and lavas. The net contrast between the resistive and conductive zones, observed approximately in all investigated sections, could be associated with the presence of differently oriented fault systems (red lines in Fig.2). Some of the detected discontinuities correlate with structural elements that develop up to the maximum investigated depth, reaching, in some cases, the proximity of the current ground level. A notable feature concerns a resistive substrate, displaced with different geometries, which gives rise to convex-shaped structures where anomalies of lower resistivity correlate to more heterogeneous and fluid-permeated materials. Furthermore, some of the identified anomalies are located below areas of thermal waters, suggesting the possibility that the associated structural features may be correlated with possible pathways of rising fluids. The presented results represent an element of knowledge which could be helpful to integrate the cartography of the structural features present in the investigated sector of Ischia territory and will contribute to a better definition of a reference geological model of the Ischia local volcano-tectonic and evolutionary context. Fig. 2 2D resistivity models of the study area.