Submarine and Subaerial Morphological Changes Associated with the 2014 Eruption at Stromboli Island

Abstract

Stromboli is an active insular volcano located in the Southern Tyrrhenian Sea and its recent volcanic activity is mostly confined within the Sciara del Fuoco (SdF, hereafter), a 2-km wide subaerial–submarine collapse scar, which morphologically dominates the NW flank of the edifice. In August-November 2014, an effusive eruption occurred along the steep SdF slope, with multiple lava flows reaching the sea. The integration of multisensor remote sensing data, including lidar, photogrammetric, bathymetric surveys coupled with SAR amplitude images collected before and after the 2014 eruption enabled to reconstruct the dynamics of the lava flows through the main morphological changes of the whole SdF slope. Well-defined and steep-sided ridges were created by lava flows during the early stages of the eruption, when effusion rates were high, favoring the penetration into the sea of lava flows as coherent bodies. Differently, fan-shaped features were emplaced during the declining stage of the eruption or in relation to lava overflows and associated gravel flows, suggesting the prevalence of volcaniclastic breccias with respect to coherent lava flows. The estimated volume of eruptive products emplaced on the SdF slope during the 2014 eruption, accounts for about 3.7 × 106 m3, 18% of which is in the submarine setting. This figure is different with respect to the previous 2007 eruption at Stromboli, when a large lava submarine delta formed. This discrepancy can be mainly related to the different elevation of the main vents feeding lava flows during the 2007 eruption (around 400 m) and the 2014 eruption (around 650 m). Besides slope accretion, instability processes were detected both in the subaerial and submarine SdF slope. Submarine slope failure mobilized at least 6 × 105 m3 of volcaniclastic material, representing the largest instability event detected since the 2007 lava delta emplacement.

Changes in the Eruptive Style of Stromboli Volcano before the 2019 Paroxysmal Phase Discovered through SOM Clustering of Seismo-Acoustic Features Compared with Camera Images and GBInSAR Data

“…Typically, an increase in Strombolian activity, in terms of the number of explosions per hour and amplitude of seismic signals associated with volcanic tremor and explosions, preceded the lava flow output [4]. They are generally caused by overflows [30] that originate from the eruptive vent regions, or by the opening of new eruptive fissures along the Sciara del Fuoco slope [31][32][33]. Fissure eruptions are also preceded by an intensification of landslides [8,34,35].…”

Landslides in the Upper Submarine Slopes of Volcanic Islands: The Central Azores

“…Sansone & Smith, 2006). Furthermore, varied effusion rates of lava flows and the pre-eruption seafloor morphology can also lead to uneven loading of slopes by lava flows, which ultimately affect slope stability (Bosman et al, 2014;Casalbore et al, 2021), so factors other than merely flow type likely affect landslide occurrences.…”

When the lava meets the sea: emplacement of the 2-4 ka San Bartolo lava flow field, Stromboli volcano (Italy)

“…Given that the base of the bench is made of unconsolidated rubble, wave action can easily erode the delta to cause sudden collapse and explosive activity (e.g., Obata and Umino 1999; Skilling 2002; Bosman et al 2014;Poland and Orr 2014). Deltas can also be formed during entry of 'a'ā lava into the sea, as was the case during the April 2007 eruption of Piton de la Fournaise (Staudacher et al 2009) or the [2002][2003]2007 and 2014 eruptions at Stromboli (Lodato et al 2007; Marsella et al 2012; Bosman et al 2014;Di Traglia et al 2018;Casalbore et al 2021). However, the case of 'a'ā lava ow entry into a lake, sea or ocean has been far less studied.…”