Holocene vertical deformation along the coastal sector of Mt. Etna volcano (eastern Sicily, Italy): Implications on the time–space constrains of the volcano lateral sliding

A comprehensive interpretative model of slow slip events on Mt. Etna's eastern flank

“…To the north, the boundary is well constrained, being represented by the Pernicana fault that shows a tectonic origin only in its western sector. However, the lack of significant and well‐defined deformation belts along the southern sliding boundary [ Azzaro et al ., ; Branca et al ., ] and the occurrence of distinct blocks characterized by different motion interacting and rotating between each other [ Solaro et al ., ; Bonforte et al ., ; Bruno et al ., ] suggest that the process is much more complex and younger than is generally stated.…”

“…The sliding sector is confined to the west by the NE and S Rift zones passing through the summit craters, and to the north and to the south by the left‐lateral Pernicana fault and by the right‐lateral Tremestieri‐ Aci Trezza fault zone, respectively (Figure ), that transfer the extensions to the east [see Acocella et al ., , and references therein]. Slope movements have been considered active for a very long time (14 ka) [ Tibaldi and Groppelli , ] and with velocities of several cm/yr, but these very significant motions do not match with clear morphological, tectonic and geological evidences, especially along the southern release of the sliding area [ Branca et al ., ]. In particular, the Tremestieri‐Aci Trezza fault zone, even though clearly evidenced by SAR and PSInSAR data [ Bonforte et al ., ], is only constituted by an alignment of discontinuous fractures that have been unable to define a discrete line of active dislocation [ Azzaro et al ., ].…”

“…According to Branca et al . [], the different behavior of distinct coastal sectors can only be explained if it is assumed that the flank sliding process has only recently been superimposed on to the long‐term volcano‐tectonic and regional uplifting. Three main contrasting models have been proposed to explain the flank sliding: deep‐seated spreading, shallow sliding and tectonic block movements [see Firth et al ., for a complete review].…”

“…However, morpho‐structural studies and geomechanical considerations seem to exclude magma intrusion as the driving force of thrust faulting. In fact, the continuity of coastal emergence between the volcanic edifice and its basement [ Firth et al ., ; Branca et al ., ], is incompatible with the differential uplift predicted by the deep‐seated spreading model, which emphasizes the independent nature of Mt. Etna's mobile flank.…”

Modelling the long‐term deformation of the sedimentary substrate of Mt. Etna volcano (Italy)

“…Recent GPS measurements, interferometric images and palaeo‐shoreline surveys show that the eastern and southern flanks of the volcano are being affected by a recent, rapid seawards motion, and some coastal areas are subsiding (Bonforte et al ., ; Branca et al ., ). Many authors have linked this deformation with a potential instability of the whole sector, induced by gravity, the load of magmatic intrusions, tectonic forcing or a combination of these (see Azzaro et al .…”