Tsunamis from prospected mass failure on the Marsili submarine volcano flanks and hints for tsunami hazard evaluation

Abstract

The Marsili Seamount (Tyrrhenian Sea, Italy) is the largest submarine volcano in the Mediterranean Sea, located in the middle of the Marsili Basin, facing the Calabrian and Sicilian coasts on its eastern side, and the coasts of Sardinia on the opposite side. It has erupted in historical times, and its summit crest is affected by widespread hydrothermal activity. This study looks at mass failures taking place at different depths on the flanks of the volcano and estimates their associated tsunamigenic potential. Mass failure, tsunami generation, and propagation have been simulated by means of numerical models developed by the Tsunami Research Team of the University of Bologna. In all, we consider five cases. Of these, three scenarios, one regarding a very small detachment and two medium-sized ones (between 2 and 3 km3 failure volume), have been suggested as possible failure occurrences in the published literature on a morphological basis and involve the north-eastern and north-western sectors of the volcano. The two additional cases, one medium-sized and one extreme, intended as a possible worst-case scenario (volume 17.6 km3), affecting the eastern flank. Results indicate that small-volume failures are not able to produce significant tsunamis; medium-size failures can produce tsunamis which dangerously affect the coasts if their detachment occurs in shallow water, i.e., involves the volcano crest; and extreme volume failures have the potential to create disastrous tsunamis. In all the simulations, tsunami waves appear to reach the Aeolian Islands in around 10 min and the coasts of Calabria and Sicily in 20 min. This study highlights that there is a potential for dangerous tsunamis generation from collapses of the Marsili volcano and as a consequence a need to intensify research on its status and stability conditions. More broadly, this investigation should also be extended to the other volcanic seamounts of the Tyrrhenian Sea, since their eruptive style, evolution, and tsunamigenic potential are still poorly known.

The tsunamigenic potential of landslide-generated tsunamis on the Vavilov seamount

“…The landslide-tsunami scenarios are reproduced by means of a set of numerical models developed by the tsunami research team of the Bologna University and already applied to several published scenarios and historical cases (e.g., Zaniboni et al, 2013;Zaniboni et al, 2014;Gallotti et al, 2020;Gallotti et al, 2021;Zaniboni et al, 2021). Firstly, the model UBO-BLOCK2 divides the sliding mass into a series of blocks passible of deformation but not of changing volume during the motion.…”

“…Simulations' parameters (basal friction, drag coefficients, etc.) are chosen following the work by Gallotti et al (2021) on the Marsili volcano, in virtue of the similar geological framework. Landslides on volcanic environments cover a wide range of movements, requiring distinct modelling efforts (see Schaefer et al, 2019 for a recent review).…”

“…In this study, we focus our attention on the Vavilov submarine volcano, located in the central part of the Tyrrhenian basin, Italy. In the past years, a series of works have been devoted to the investigation of the numerous submarine structures of the Tyrrhenian Sea (Rovere et al, 2016;Cocchi et al, 2017) also in a landslidegenerated tsunami perspective (Fornaciai et al, 2019;Esposti Ongaro et al, 2021;Gallotti et al, 2020;Gallotti et al, 2021). This latter aspect is an arduous task on this kind of remote and poorly investigated structures due to the lack of specific information about the volcano and its characteristics.…”

Tsunami potential source in the eastern Sea of Marmara (NW Turkey), along the North Anatolian Fault system

“…Indeed, the code can handle such grid densification at specific sites by implementing a nested-grid technique. More details about the code and applications to real cases can be found in Tinti and Tonini (2013), Tinti et al (2011), Zaniboni et al (2014, and Gallotti et al (2020Gallotti et al ( , 2021.…”

Unraveling Past Submarine Eruptions by Dating Lapilli Tuff-Encrusting Coralligenous (Actea Volcano, NW Sicilian Channel)

“…On the basis of geoarchaeological studies and investigation of tsunamigenic deposits in Stromboli Island, a medieval age tsunami in southern Tyrrhenian Sea, due to volcanic paroxysm eruption and landslides along the Sciara del Fuoco flank, was matched with historic documents describing destruction in Naples harbor, about 200 km from the volcano (Rosi et al, 2019). Recent studies are trying to evaluate the tsunamigenic potential of considerable submarine volcanic complexes, as the Marsili seamount (Tyrrhenian Sea), the largest active submarine volcano in the Mediterranean Sea (Gallotti et al, 2021), and the submerged part of Campi Flegrei caldera, located on the western part of the densely inhabited area of Naples (Paris et al, 2019).…”