Submarine mass-movements on volcanic islands: Examples from the aeolian archipelago (Italy)

Abstract

High-resolution bathymetry collected around the Aeolian islands allowed the recognition of a large spectrum of geomorphic features referable to mass-movements. Besides large-scale sector collapse scars (recognized only at Stromboli), two main groups of medium-scale submarine slides are distinguished based on their size, geometry and location. The first group is defined by semi-circular slide scars at hundred-meter scale, indenting the outer edges of insular shelves and overlying sedimentary deposits in the first hundred(s) m of water depth (wd). The second group is defined by downslope-elongated scars carving the steep submarine flanks of volcanic edifices and interpreted as retrogressive slope failures. Within this latter group, particular attention has been devoted to the frequent slope failures affecting the submarine portion of the Sciara del Fuoco at Stromboli, and to the nested slide scars affecting the old and extinct Banco del Bagno submarine volcanic center at Lipari. The main predisposing and triggering factors, recurrence times and tsunamigenic potential of the recognized mass-movements are briefly discussed to provide some insights into geohazard assessment of the area.