Etna volcano - eruption update (28 Feb-30 April 2021)

Aktualisiert: 28. Sep. 2021 01:53 GMT

Etna volcano (Italy): swarm of tiny earthquakes under eastern flank

Fr, 30. Apr 2021, 16:37
16:37 PM | VON: T
Epicenters and depth of recent earthquakes at Etna volcano
Epicenters and depth of recent earthquakes at Etna volcano
Ash emission from the New SE crater this morning (image: LAVE webcam)
Ash emission from the New SE crater this morning (image: LAVE webcam)
Weak glow visible during a weak emission of the vent at night
Weak glow visible during a weak emission of the vent at night
A swarm of small earthquakes has been occurring under the volcano since yesterday: about 50 tiny quakes with magnitudes between 1.0 and 2.2 were detected over the past 24 hours in an area on the lower eastern flank, roughly between the towns of Milo, Mascali and Giarre.
The depths of the quakes are mostly between 10-20 km in the lower crust where they might - or might not - indicate small events related to magma storage at lower reservoirs. It seems unlikely this will directly affect or translate into changes of the surface activity of the volcano in any near future. This is, at least, as long as the earthquakes are small as they are and don't approach shallower levels.

New SE crater calms down again, remains weakly active
At the surface, the volcano has remained quite calm. The recently observed trend of increasing activity at the New SE crater has reversed again. During the past 36 hours, there were only sporadic ash emissions with weak glow visible sometimes at night, suggesting that explosions are only small and occurring deep inside the vent, without ejecting glowing material above the crater rim.

After almost 4 weeks of calm, New SE crater is showing signs of life again!

Update Tue 27 Apr 2021 16:37
Strombolian explosion at Etna's New SE crater late on 26 April 2021 (image: Boris Behncke / facebook)
Strombolian explosion at Etna's New SE crater late on 26 April 2021 (image: Boris Behncke / facebook)
Current tremor signal (image: INGV Catania)
Current tremor signal (image: INGV Catania)
After almost 4 weeks of calm since the last paroxysm (during 31 Mar-1 Apr), the New SE crater is again showing signs of coming back to life:
Two strong strombolian explosions occurred in the night of 24-25 April and in the morning of 26 April at the Southeast Crater, followed by weak glow and smaller occasional explosions since last evening.
It is too early to predict whether this activity will continue and possibly increase towards another strong eruptive phase with lava fountaining (or paroxysm), but it might very well do so. Volcanic tremor has been showing a gradual slow increase during the past two days.
According to volcanologist Dr. Boris Behncke from INGV Catania, ground deformation is still extremely low, compared to what was seen between the period of inflation (reflecting magma charging) during last autumn-winter and the deflation caused by the series of paroxysms in February-March.
Only Etna will know what is coming up next!

17th paroxysm of Etna - spectacular video

Update Fri 02 Apr 2021 09:27
Etna's new effusive vent at the southern base of the SE crater active during 31 Mar - 1 April (image: Michele Mammino)
Etna's new effusive vent at the southern base of the SE crater active during 31 Mar - 1 April (image: Michele Mammino)
The latest lava fountain episode or paroxysm, counting number 17 since 16 Feb 2021, has ended. Volcanic activity at the New SE crater gradually and very slowly declined since the afternoon to finally ceased at some point in the late (?) evening.
This eruptive episode had been very remarkable, even for Etna standards, and for several reasons:
First, while its intensity at peak phase may not have quite reached the same values as many of the previous 16 episodes since mid February, it lasted significantly longer than any other, with about 12 hours of lava fountaining, and a very long build-up and declining phases, making the whole episode lasting almost two days!
Secondly, the opening of a new effusive vent at the southern base of the cone in the morning of 31 March also marked a significantly different behavior than observed previously. As to its causes, we can only speculate that the uppermost parts of the conduit system had become sufficiently unstable by now, so that when pressure in the upper conduit increased, it opened a fracture at a lower point, at the southern base of the cone, and allowed some of the magma to find an easier there.
This would explain why the intensity of the eruption later at the summit vent was a bit lower,- some of the magma was "diverted" just before reaching the summit.

Local Etna specialist filmmaker Michele Mammino took some of the most remarkable videos of this eruption, in particular close-up shots of the new fissure vent that was active at the southern base of the New SE crater. Enjoy:


It is worth mentioning that during the whole time of the eruptive phase at the New SE crater, the other summit vents continued their intermittent mild strombolian activity.

Eruptive episode still going on strong

Update Thu 01 Apr 2021 07:15
Activity from Etna's New SE crater with two lava flows into Valle del Bove (image: INGV themal webcam on east flank)
Activity from Etna's New SE crater with two lava flows into Valle del Bove (image: INGV themal webcam on east flank)
Current tremor signal (image: INGV Catania)
Current tremor signal (image: INGV Catania)
The 17th paroxysm (lava fountain episode) from the New SE crater in a row has been going on all night, and is still increasing as of 9 am this morning local time, making it a record-breaker in terms of duration.
The National Institute of Geophysics and Volcanology (INGV) in Catania reported that strombolian activity at the SE Crater passed to sustained lava fountains from around midnight, meaning that these now have been continuing for more than 9 hours! The eruption column has been rising to an altitude of approx. 7 km (20,000 ft) and dispersing towards the SSW, where it is raining black lapilli and volcanic sand now.
The effusive activity from the new fissure vent at the southern base, which had been active since yesterday morning continues to produce weak explosive activity and to feed a lava flow that flows SSE into the western sector of the Valle del Bove.
A second lava flow began as overflow from the eastern summit vent of the crater shortly after midnight, in tandem with the onset of lava fountains at the summit, and is traveling eastward down into the upper part of the Valle del Bove.
Finally, while all this action is happening at the SE crater, the eruptive activity at the other summit craters remains unchanged as if their conduits were completely independent from the one SE crater's.

17th lava fountaining episode at New SE crater started

Update Wed 31 Mar 2021 21:54
Strong activity from the new effusive vent (glow in center of image) and lava fountains from the summit vent of Etna's New SE crater (center right) (image: INGV webcam)
Strong activity from the new effusive vent (glow in center of image) and lava fountains from the summit vent of Etna's New SE crater (center right) (image: INGV webcam)
Same view on the thermal webcam (INGV)
Same view on the thermal webcam (INGV)
Thermal view from the east side at Monte Cagliato showing the advancing lava flow from the southern vent and the lava fountains of the summit vent (image: INGV webcam)
Thermal view from the east side at Monte Cagliato showing the advancing lava flow from the southern vent and the lava fountains of the summit vent (image: INGV webcam)
Current tremor signal (image: INGV Catania)
Current tremor signal (image: INGV Catania)
During the past hours, activity has gradually been (and still is) increasing at the New SE crater, and it has entered the lava fountaining or paroxysmal phase.
While activity from the the new eruptive vent that opened this morning at the southern base of the SE crater continued to increase, feeding lava flows, in particular one directed south and southwest towards the Valle del Bove, the summit vent has been activated again to join the action. Its activity began with smaller explosions that quickly grew in intensity and now started to generate lava fountains, constantly increasing in height and likely already surpassing 200 meters as of now.
Resulting from this, a significant ash plume began to rise above the crater and is drifting in southerly directions. The volcano observatory in Catania raised the aviation color code to RED due to these strong ash emissions, likely to increase further in the coming hours.
The 17th paroxysm of Etna's New SE crater since mid February has started. How long it might last could range from few to many hours.

New lava flow from southern base of SE crater

Update Wed 31 Mar 2021 18:36
View of the New SE crater from Schiena dell'Asino (image: LAVE webcam)
View of the New SE crater from Schiena dell'Asino (image: LAVE webcam)
Rising tremor signal (image: INGV Catania)
Rising tremor signal (image: INGV Catania)
While activity and volcanic tremor at the SE crater complex overall continue to increase, the action seems to be been taking a different path this time, when compared to what happened in the build-up phases before the previous 16 paroxysms:
Already early this morning, around 3:30 am local time, a new effusive vent opened on the southern base of the crater complex at approx. 3000 m elevation and began to feed several small lava flows towards the SSW, S and SSE.
The volcano observatory reported that the SSW and S lava flows appeared poorly fed and their fronts were confined between 2800 - 2900 m asl. The SSE flow was more voluminous and had almost reached the edge of the Valle del Bove by early evening. This activity is strongly increasing at the time of update and it is still unclear whether it will produce lava fountains.
In any case, today marks a significant change in the behavior of the New SE crater, at least when it comes to its manifestation at the surface. Activity essentially has moved back to a location more to the S or SW of the cone, rather than continuing to propagate towards the eastern end of the feeding conduit. In addition, a vent at a lower location might mean that the summit vents have become more difficult for the magma column to reach.
Usually, before the onset of lava fountaining, activity had almost always begun at the summit vents of the SE cone complex, followed by a lava flow emerging from the eastern end of the eruptive fracture, which cuts through the upper parts of the cone.
Eventually, especially during the first paroxysms, other vents along the S and SW parts of the fracture activated as well, also feeding fountains and often a smaller lava flow to the S or SW. During March, activity gradually had moved more and more to the eastern end, with no activity at the southern and western end any more. This clearly has changed now.
What happens on Europe's most active volcano remains fascinating to follow!
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