Gravity study of the Casamicciola area (Ischia Island, Southern Italy)
Lorenzo Ricciardi 1; Tommaso Pivetta2; Stefano Carlino2; Umberto Riccardi1; Valeria Paoletti1; Nicola Alessandro Pino2; Giovanni Florio1
Affiliations: 1Dipartimento di Scienze della Terra, dell\'Ambiente e delle Risorse (DiSTAR), Università degli Studi di Napoli Federico II, Naples, Italy; 2Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano (INGV - OV), Naples, Italy
Presentation type: Poster
Presentation time: Thursday 16:30 - 18:30, Room Poster Hall
Poster Board Number: 141
Programme No: 2.1.51
Abstract
Ischia Island, in the Gulf of Naples, is a key site for studying the interplay between volcano-tectonic processes, seismicity, and geothermal systems. Its geodynamic evolution, driven by the resurgence of Mt. Epomeo following to the Green Tuff eruption (60-56 ka), is characterized by magmatic intrusions, about 900 m of uplift, and an active geothermal system. The island's northern sector, however, faces high seismic risk, highlighted by the destructive 1883 and 2017 (Mw 3.9) earthquakes linked to the Casamicciola fault. This fault, with its shallow seismogenic sources and complex geometry, is central to local seismic hazard. A new gravity survey added 78 stations to the historical data, yielding a high-resolution dataset of ~16 sites/km² around the fault. Free-Air and Bouguer anomaly maps reveal significant horizontal density variations associated with subsurface structures. Edge analysis techniques, (e.g., Enhanced Horizontal Derivative, EHD), allowed the detection of structural features and the localization of horizontal density contrasts. A constrained 3D inversion, incorporating borehole data, geophysical models, and results of gravity data analyses, was applied to develop detailed density models of the fault system. Preliminary results constrain the fault's geometry and provide knowledge to study its interactions with geological and geothermal processes.