Experimental study of the interplay between magmatic rift intrusion and flank instability with application to the 2001 Mount Etna eruption

Abstract

Mount Etna volcano is subject to transient magmatic intrusions and flank movement. The east flank of the edifice, in particular, is moving eastward and is dissected by the Timpe Fault System. The relationship of this eastward motion with intrusions and tectonic fault motion, however, remains poorly constrained. Here we explore this relationship by using analogue experiments that are designed to simulate magmatic rift intrusion, flank movement, and fault activity before, during, and after a magmatic intrusion episode. Using particle image velocimetry allows for a precise temporal and spatial analysis of the development and activity of fault systems. The results show that the occurrence of rift intrusion episodes has a direct effect on fault activity. In such a situation, fault activity may occur or may be hindered, depending on the interplay of fault displacement and flank acceleration in response to dike intrusion. Our results demonstrate that a complex interplay may exist between an active tectonic fault system and magmatically induced flank instability. Episodes of magmatic intrusion change the intensity pattern of horizontal flank displacements and may hinder or activate associated faults. We further compare our results with the GPS data of the Mount Etna 2001 eruption and intrusion. We find that syneruptive displacement rates at the Timpe Fault System have differed from the preeruptive or posteruptive periods, which shows a good agreement of both the experimental and the GPS data. Therefore, understanding the flank instability and flank stability at Mount Etna requires consideration of both tectonic and magmatic forcing.

Large dyke intrusion and small eruption: The December 24, 2018 Mt. Etna eruption imaged by Sentinel‐1 data

“…This wide and intense deformation was accommodated by the slip on some faults on the volcano's flanks. It is noteworthy that the dynamics of the faults cutting the flanks of the volcano is often solicited by significant pressure increase in the plumbing system (Le Corvec, Walter, Ruch, Bonforte, & Puglisi, ; Bonforte, Bonaccorso, Guglielmino, Palano, & Puglisi, ). This is the case, for instance, of the SE fault activated during the 2001 (Bonforte, Guglielmino, Palano, & Puglisi, ; Bonforte et al., ) and 2008 eruptions (Bonforte et al., ) and of the PFS, activated in 1994 (Puglisi, Bonforte, & Maugeri, ; Neri et al., ; Bonforte, Branca, & Palano, ; Bonforte, Carbone, Greco, & Palano, ).…”

Gravitational collapse of Mount Etna’s southeastern flank

“…Inflation and dyke intrusions can thus favor episodic accelerations of flank movement in addition to large-scale continuous gravitational sliding. Both processes may well interact with and influence each other, as demonstrated by analog models ( 32 ).…”

Directional flank spreading at Mount Cameroon volcano: Evidence from analogue modeling

“…Deformation structures affecting the lower flanks at these other volcanoes are thus more difficult to map. Several of these volcanoes show strong evidence for continuous, usually asymmetric, flank spreading driven by gravity and/or repeated magmatic intrusions [see Le Corvec and Walter , ], sometimes in interaction with tectonic faulting (e.g., Etna) [ Le Corvec et al ., ]. Processes documented here—i.e., laterally constrained flank spreading, associated with summit subsidence, and shallow slumps affecting upper slopes due to differential spreading velocity of the lower flanks—are expected to similarly apply to some of these structures where both summit subsidence and flank slumping (e.g., Hilina Pali faults, Kilauea) [ Morgan et al ., ] or sector collapses are observed simultaneously [ Oehler et al ., ].…”