Three‐Dimensional Modeling of Mount Etna Volcano: Volume Assessment, Trend of Eruption Rates, and Geodynamic Significance

Abstract

3‐D modeling of Mount Etna, the largest and most active volcano in Europe, has for the first time enabled acquiring new information on the volumes of products emitted during the volcanic phases that have formed Mount Etna and particularly during the last 60 ka, an issue previously not fully addressed. Volumes emitted over time allow determining the trend of eruption rates during the volcano's lifetime, also highlighting a drastic increase of emitted products in the last 15 ka. The comparison of Mount Etna's eruption rates with those of other volcanic systems in different geodynamic frameworks worldwide revealed that since 60 ka ago, eruption rates have reached a value near to that of oceanic‐arc volcanic systems, although Mount Etna is considered a continental rift strato‐volcano. This finding agrees well with previous studies on a possible transition of Mount Etna's magmatic source from plume‐related to island‐arc related. As suggested by tomographic studies, trench‐parallel breakoff of the Ionian slab has occurred north of Mount Etna. Slab gateway formation right between the Aeolian magmatic province and the Mount Etna area probably induced a previously softened and fluid‐enriched suprasubduction mantle wedge to flow toward the volcano with consequent magmatic source mixing.

Slab Detachment, Mantle Flow, and Crustal Collision in Eastern Sicily (Southern Italy): Implications on Mount Etna Volcanism

“…Furthermore, about 50° horizontal‐axis clockwise rotation (from its original position) of the uppermost slab fragment (Figure 7b‐1) suggests that, after being detached, it was pushed and rotated by the advancing fore‐arc mantle (Figure 7b‐2). A low‐velocity zone recently found through tomographic images (Scarfi et al, 2018), together with a local gravity anomaly minimum and relative maxima of heat flow just north of Mount Etna (see Barreca, Branca, & Monaco, 2018, and Figure 9c) support penetration of less dense material in the Etnean region.…”

“…Variations in the ratios suggest that the (depleted) mantle wedge initially feeding the western Eolian Arc volcanic system might have been pushed and replaced by primary mantle coming from the north in line with slab‐hinge retreat toward the south. The transition of Mount Etna lavas from a mantle‐plume (Peccerillo, 2017) to an island arc magmatic source, based on petrologic data (Corsaro & Pompilio, 2004; Peccerillo, 2017; Schiano et al, 2001), confirms that mantle has flowed from the nearby Eolian sector, also leading Mount Etna to reach eruption rates near to that of oceanic arc volcanic systems in the last 60 ka (Barreca, Branca, & Monaco, 2018). Following the southward mantle migration, the intraplate (Africa/Ionian) crustal shortening below Mount Etna is here interpreted as the result of a far‐field geodynamic process triggered by the trench‐parallel breakoff of the Ionian slab (see above).…”

“…The different phases in the evolution of Mount Etna have been marked by significant compositional variations of magmas (Corsaro & Pompilio, 2004, and references therein; Peccerillo, 2017, and references therein), in the eruptive style (Del Carlo et al, 2004), and in the emitted volume (Barreca, Branca, & Monaco, 2018; Branca & Ferrara, 2013) of volcanic products. In this section, we retrace the Mount Etna evolution focusing on major variations that have conditioned the geologic evolution of the volcano.…”

Geometry of the Deep Calabrian Subduction (Central Mediterranean Sea) From Wide‐Angle Seismic Data and 3‐D Gravity Modeling

“…Recent geodetic work provided evidence for toroidal flow around the retreating slab edges of the Calabrian subduction system expressed by counterclockwise rotations at the northern and clockwise rotations at the southern edge of the slab corresponding to movements predicted by STEP faults (Palano et al, ). Recent tomographic studies imaged a trench‐parallel slab break‐off on both sides of the slab, which might be still propagating, narrowing the slab (Barreca et al, , ; Scarfì et al, , ). Horizontal tearing affecting both sides of the slab was proposed to result in a narrowing of the subduction system and enhanced subsidence along the still‐intact segment of the slab (Scarfì et al, ).…”

Vascular plant species diversity of Mt. Etna (Sicily): endemicity, insularity and spatial patterns along the altitudinal gradient of the highest active volcano in Europe

“…Etna region was concentrated along the Ionian Sea coast between 220 and 121 ka ago De Beni et al, 2011). According to Branca & Ferrara (2013), about 80% of the volcanic products were erupted only in the past 110 ka due to the stabilization of the magma source and from 15,000 years ago, the younger volcanics mantled most of the previous edifice (88% of the area) with a widespread cover of lava flow fields and pyroclastc deposits (Branca et al, 2011a;Barreca, Branca & Monaco, 2018). This, joined to a general process of tectonic uplifting, sometimes broken by the subsidence related to flank sliding of this volcanic edifice (Branca et al, 2014), contributes to understand the present structure of Etna volcano but also to highlights relevant constraints and evolutionary chances for the plants colonizing this mountain in which soils are rejuvenated quite frequently, especially at higher elevations, not only with lava flows but above all with falls of volcanic ash and tephra.…”