Editing Mount Etna (section)

===Geological history===
[[File:Etna storia geologica.png|thumb|upright=1.85|Simplified [[Cross section (geology)|geological cross section]] of the Mount Etna volcanic complex (not to scale), showing its evolution from an early stage of submarine fissural activity, producing pillow lavas and a first [[shield volcano]], to a subsequent mixed effusive and explosive activity building three main [[stratovolcano]] stages (Monte Calanna; Trifoglietto 1; Trifoglietto 2), then to the present Mongibello system (which has developed in two successive stages from about 15,000 years ago). The volcanic activity has gradually shifted from SE to NW (from offshore to onshore). The Valle del Bove is the former eastern flank of the volcano, which collapsed about 64,000 years ago and thus allows the older volcanic edifices to be recognized.]]
[[File:Mount Etna from the south 060313.JPG|thumb|Mount Etna from the south with the smoking peak in the upper left and a lateral crater in the centre]]
Volcanic activity first took place at Etna about 500,000 years ago, with eruptions occurring beneath the sea off the ancient coastline of Sicily.<ref>{{cite web|url=http://vulcan.wr.usgs.gov/Volcanoes/Italy/description_italy_volcanics.html|title=Mt. Etna|last=Martin-Schutz, Alicia}}</ref> About 300,000&nbsp;years ago, volcanism began occurring to the southwest of the summit (centre top of the volcano), then activity moved towards the present centre 170,000&nbsp;years ago. Eruptions at this time built up the first major volcanic edifice, forming a stratovolcano in alternating explosive and effusive eruptions. The growth of the mountain was occasionally interrupted by major eruptions, leading to the collapse of the summit to form [[caldera]]s.

From about 35,000 to 15,000&nbsp;years ago, Etna experienced some highly explosive eruptions, generating large [[pyroclastic flow]]s, which left extensive [[ignimbrite]] deposits. Ash from these eruptions has been found as far away as south of [[Rome]]'s border, {{convert|800|km|mi|0|abbr=on}} to the north.

Thousands of years ago, the eastern flank of the mountain experienced a catastrophic collapse, generating an enormous [[volcanic landslide|landslide]] in an event similar to that seen in the [[1980 eruption of Mount St. Helens]]. The landslide left a large depression in the side of the volcano, known as 'Valle del Bove' (Valley of the Ox). Research published in 2006 suggested this occurred around 8,000 years ago, and caused a huge [[tsunami]], which left its mark in several places in the eastern [[Mediterranean Sea|Mediterranean]].<ref>It has been suggested that this was the reason why the settlement of [[Atlit Yam]] ([[Israel]]), now below sea level, was suddenly abandoned around that time. See {{Citation |last1=Pareschi |first1=M. T. |first2=E. |last2=Boschi |name-list-style=amp |first3=M. |last3=Favalli |year=2007 |title=Holocene tsunamis from Mount Etna and the fate of Israeli Neolithic communities |journal=Geophysical Research Letters |volume=34 |issue= 16|pages=L16317 |doi=10.1029/2007GL030717 |bibcode=2007GeoRL..3416317P|s2cid=129407252 |doi-access=free }}. This claim has been contested, however, as "there is no evidence of tsunami deposits, nor of sudden and catastrophic changes such as damaged structures, whole animal carcases or evidence of traumatic injury, such as might be expected to result from a tsunami event" (Galili E., Rosen B., Evron M.W., Hershkovitz I., Eshed V., Horwitz L.K. (2020) [https://doi.org/10.1007/978-3-030-37367-2_23 Israel: Submerged Prehistoric Sites and Settlements on the Mediterranean Coastline—the Current State of the Art]. In: Bailey G., Galanidou N., Peeters H., Jöns H., Mennenga M. (eds) ''The Archaeology of Europe’s Drowned Landscapes. Coastal Research Library'', vol 35. Springer, Cham). See also, Galili, E., Horwitz, L. K., Hershkovitz, I., Eshed, V., Salamon, A., Zviely, D., Weinstein‐Evron, M., and Greenfield, H. (2008), [https://doi.org/10.1029/2008GL033445 Comment on "Holocene tsunamis from Mount Etna and the fate of Israeli Neolithic communities" by Maria Teresa Pareschi, Enzo Boschi, and Massimiliano Favalli], ''Geophysical Research Letters'', 35, L08311.</ref>

The steep walls of the valley have suffered subsequent collapses on numerous occasions. The [[stratum|strata]] exposed in the valley walls provide an important and easily accessible record of Etna's eruptive history.

The most recent collapse event at the summit of Etna is thought to have occurred about 2,000&nbsp;years ago, forming what is known as the Piano Caldera. This caldera has been almost entirely filled by subsequent lava eruptions but is still visible as a distinct break in the slope of the mountain near the base of the present-day summit cone.

Mount Etna is moving towards the Mediterranean Sea at an average rate of {{convert|14|mm|abbr=on}} per year, the massif sliding on an unconsolidated layer above the older sloping terrain.<ref>{{cite journal |last1=Murray |first1=J.B. |last2=van Wyk de Vries |first2=B. |last3=Pitty |first3=A. |date=April 2018 |title=Gravitational sliding of the Mt. Etna massif along a sloping basement |journal=[[Bulletin of Volcanology]] |volume=80 |issue=4 |page= 40|doi=10.1007/s00445-018-1209-1 |pmid=31258237 |pmc=6560784 |bibcode=2018BVol...80...40M |url=http://oro.open.ac.uk/54264/1/445_2018_Article_1209.pdf }}</ref><ref>[https://www.science.org/doi/10.1126/sciadv.aat9700 Gravitational collapse of Mount Etna’s southeastern flank]</ref>