SummaryThe 21st paroxysmal eruption of Etna's New SE crater started early on 4 March, following a week of intermittent strombolian activity and accompanied by a steep rise of volcanic tremor. Lava fountains several 100 m tall were rising from the summit crater during the peak phase of the eruption, generating a 2-3 km tall tephra and steam plume, which rose almost vertically due to the absence of strong winds, and drifted SE.
A lava flow was erupted from the SE trending fissure and went towards and partly into the Valle del Bove.
Episodes of violent, explosive lava-snow interaction were observed producing large billowing steam plumes and probably generating small pyroclastic flows, similar to such events during previous paroxysms.
Etna New SE crater paroxsym nr 21 on 4 March 2012
Update Sun 11 Mar 23:33Almost a week has passed since the last paroxysm and Etna has been quiet. It will be interesting to see whether a new eruption is going to happen in the next weeks.
Changes to the SE crater complex
Update Tue 06 Mar 12:29
"For the first time since the violent episode of lava fountaining (paroxysm) on 4 March 2012, we had a crystal-clear view of the summit of Mount Etna on the morning of 6 March 2012.
... The most interesting detail to be revealed was the new fissure on the southwestern flank of the New Southeast Crater cone, seen here pretty much vertically below the steaming summit of the old Southeast Crater cone (in the left half of the picture).
The fissure ripped open at the climax of the 4 March paroxysm, around 07:50 GMT (= local time -1), and released a lava flow that mixed with thick snow at the base of the cone, generating a pyroclastic flow and a lahar (a volcanic mudflow). The dark streak cutting diagonally across the lower half of the image is the path of that lahar; some of it was later covered by a small lava flow that oozed from the lower end of the fissure for many hours after the cessation of lava fountaining.
All is quiet again, with only some wisps of gas coming from numerous fumaroles (gas vents) on the crater rim, which are incandescent at night. Who knows how long it will take until the next lava fountain, and whether that fissure on the southwest flank of the new cone will open again?"
Eruption has ended
Update Sun 04 Mar 10:50The eruption has ended, this time very quickly as often during paroxysms of Etna. Tremor is back to near zero, and the eruption column and lava fountains have disappeared, as the magma column inside the conduit has dropped.
The wait for the next eruption can begin!
Eruption decreases - probably the near end of the paroxysm
Update Sun 04 Mar 10:19
Steam and dust obscure views, but it seems that there is either a lava flow on the SW or western side, or another pyroclastic flow reached the S-SW flat area beneath the summit cones, near Torre del Filosofo, and far from the erupting vent (see webcam images).
Update Sun 04 Mar 09:56
This would make it a relatively short paroxysm, especially when compared to the previous one on 8 Feb, which lasted about 6 hours.
Update Sun 04 Mar 23:27The following video shows the pyroclastic flow we mentioned earlier during the probably most spectacular phase of the eruption, when a new vent opened on the SW flank in the saddle between the old SE and the New SE cone, generating a pyroclastic flow caused by violent mixing of ejected lava and debris with rapidly evaporating snow.
Update Sun 04 Mar 09:40
Update Sun 04 Mar 09:14
New paroxysm of SE crater (nr 21)
Update Sun 04 Mar 08:49
Lava fountains are now rising from the crater along with a dense column of tephra and steam reaching about 2 km and drifting SE. A lava flow can be seen flowing from the southeasterly aligned fissure taking the normal path towards the Valle del Bove.
The eruption is still increasing in strength, but is probably already near its peak.
Update Sat 03 Mar 22:17
Weak strombolian activity continues from New SE crater
Update Sat 03 Mar 19:12
Update Fri 02 Mar 21:38Sporadic small strombolian explosions from the New SE crater have been observed tonight again, occurring at irregular intervals during more active phases with 10-15 explosions per hour alternating with phases of quiet of sometimes several hours.
Update Fri 02 Mar 09:25It seems that the activity has gone down, as there seem not to have been new eruptions over the night. Tremor as well is at low levels, but that can all change quickly.
New strombolian activity from New SE crater
Update Thu 01 Mar 17:56
Elevated volcanic tremor could be from deep explosive activity within North-East crater
Update Tue 28 Feb 09:47
"The rising volcanic tremor amplitude is not a true increase in the volcanic tremor, but an effect of numerous (and increasingly frequent) explosive events within the Northeast Crater.
The constant ground vibration (the true volcanic tremor) is rather weak, but for the calculation of the RMS tremor amplitude graph, 5-minute intervals are averaged, and these include many of the explosion signals, so the tremor amplitude appears elevated.
In any case, Etna is a bit restless, but the situation is currently different from the typical "prelude" of a new lava fountaining episode ..."
New weak strombolian activity from New SE crater
Update Sat 25 Feb 00:57
Volcanic tremor is still at low levels, but has recovered from the drop after the rise observed over the last weekend.
Update Thu 23 Feb 07:59After a few days of bad weather and heavy snowing, the upper parts of Etna are now white except the still warm recent lava flows. Whatever has caused the gradually rising tremor signal up to Tuesday, possibly (but speculation) a rise in the magma column inside the conduit feeding the New SE crater, and triggering expectations to see the 21st paroxysm soon, seems to have ended - the signal is now back down at normal background levels.
Update Wed 22 Feb 19:08
Update Tue 21 Feb 22:57Etna is unpredictable. Just after our previous update, the tremor signal (currently the only available indicator) dropped sharply to almost half its value. Probably, no "show" tonight!
Update Tue 21 Feb 21:32The tremor is still rising, and the signal looks very similar to the initial stages of most paroxysms during the past 13 months. Unless Etna is doing something quite different (which is very possible, too), it seems more and more as if the next eruption could happen very soon.
Tremor continues to rise slowly, but bad visibility
Update Tue 21 Feb 16:33
No explosions were noted during the previous 3 days, but an incandescent spot on the southern rim of the New SEC was visible, suggesting that temperatures there were increasing. Something might be in the making...
Update Sun 20 Feb 13:30
At night, no glow was visible either. A possibility is that the rising tremor is from activity beneath the NE crater. Visibility is probably going to be reduced in the next few days as the weather forecast is deteriorating.
Another build-up towards a paroxysm?
Update Sat 18 Feb 10:11Over the past days, there have been sporadic ash emissions from the New SE crater, and the tremor signal is showing a fluctuating, but overall increasing trend, very much like in the 10 days prior to the last paroxysm on 8-9 February.
If another eruption occurs in the next days, it would mean that the intervals between eruptions are becoming again shorter.
4 March 2012 paroxysm