Structural features of the shallow plumbing system of Vulcano Island Italy

Abstract

Abstract In this study, we integrate information gathered from surface geology and tectonics with the results of a shallow (0–2 km b.s.l.) seismic tomography of Vulcano Island (Italy), obtained from the analysis of local earthquakes. The observed low Vp regions correspond to caldera filling products, mainly consisting of pyroclastics, tuffs, lava flows and hyaloclastites. High-velocity anomalies represent intrusive bodies. The striking correspondence between the stratigraphy from deep wells and the calculated velocity structure allows us to reconstruct the geometry and distribution of a main intrusion and to recognize some intra-caldera depressions. The shape and location of the high and low Vp anomalies are consistent with NW–SE and N–S strikes. Eruptive centres younger than 42 kyr, as well as the structural depressions of Vulcano and of the neighbour Lipari Island, align along a N–S direction. The combined interpretation of the available structural data and of the results from the tomography suggests that magmatic reservoirs of Vulcano at shallow depth (>0.5 km) align along a NW–SE strike but their shape is controlled by N–S striking normal faults and/or cracks that accommodate the right-lateral movements of the NW–SE strike-slip fault system.