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The twin Southeast Craters and that strange rock needle

As devoted followers of my photostream will have noted, there has been quite a lot of change to the shape of Etna's summit area this year. This is mostly the growth of a large new cone made of loose volcanic (pyroclastic) material, which is piling up around the New Southeast Crater - not long ago, it was still called "pit crater" - and had become more than 150 m tall before the latest two paroxysmal episodes on 29 August and 8 September 2011. The southern and northern rims of the crater have grown further during these latest two episodes, but the eastern and southeastern flanks of the cone have suffered from more destructive, mass wasting processes, involving landslides, opening of fissures, and entrainment of sections of the cone by lava flows.


The most peculiar effect of the latest paroxysm on 8 September is the formation of a rather conspicuous pinnacle of rock, or a "needle", on the lower southeast flank of the new cone. This thing is widely visible especially from northeast and north, even from Taormina, and there are already a few rather spectacular close-up views of it on Flickr (which I will link to in the comments below). Its height was initially about 25-30 m, though since then chunks of it have repeatedly fallen off, reducing both its height and width. This structure, which consists of an uplifted and rotated portion of the cone's flank (presumably entrained by lava flows and rotated when encountering an obstacle), composed of stratified scoriae, is certainly rather weak and might disintegrate even before the next paroxysmal episode will definitely cancel any trace of it.


This view was taken from the "Mareneve" road on Etna's northeast flank on the morning of 10 September; it shows the "old" (sulfur-coated) Southeast Crater cone at right, the "new" Southeast Crater cone in the center, and the rock needle at left. Furthermore, near the left margin of the image, a reddish-brown patch corresponds to the zone where lava was emitted and sporadic explosions took place during the 8 September paroxysm, presumably when new vents opened there. A similar, though much smaller brown spot lies a bit further upslope, just a little below the yellow sulfur patch, and this is the first of these vents that opened early during the paroxysm of 8 September.


Etna continues to surprise us, and this makes it more and more fascinating and intriguing.

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Taken on September 10, 2011