After the rather surprising onset of a new intense phase of activity in the late afternoon, the New SE crater produced not only one, but two paroxysms during the night, marking them the 26th and 27th such episodes for 2021 so far.
Likely compensating the suddenly much shorter intervals, the eruptions were significantly weaker, though, when compared with earlier paroxysms observed in Feb-Mar and May this year.
Last night’s activity reached its peak between around 20:30-21:30 local time, when explosions from the New SE crater merged into lava fountains and the lava flow towards the SW was most strongly fed.
Activity abruptly ceased and volcanic tremor dropped sharply and returned to low levels by 22:30. The volcano remained calm until 02:40 am early this morning. Calm, this is except occasional glow hinting towards that strombolian explosions from Voragine central summit crater still go on as well. Like the other summit vents of Bocca Nova and NE crater, the Voragine seems to act almost completely unaffected by what is happening at the New SE crater.
The calm didn’t last very long, though: at 02:40, activity suddenly picked up again at the New SE crater and quickly developed a second paroxysm with lava fountaining that lasted until around 4am, before ceasing again. As during the preceding phase, yet another lava flow was erupted from the main vent of the New SE crater towards the southwestern base.
The following time-lapse shows the whole sequence of activity between yesterday afternoon and this morning:
How the activity likely will continue is uncertain – given that the volcano has broken the rather stable pattern of 40-48 hours between individual events, it hints that it is in a more unstable phase right now, and it can only be speculated upon what and when might come next.
Morphological changes to crater occurred after the latest effusive eruption from Nyiragongo volcano (image: @simoncarn/twitter)
New post-eruption satellite images of the volcano reveals morphological changes in the volcano’s summit crater. From the latest available imagery (25 May) and compared to the image from 13 May it seems to has partially collapsed. According to satellite image from Sentinel 1, lava flows that have stopped at in the village of Buhene in the outskirts of Goma City, erupted from Shaheru crater located on the south flank of Nyiragongo volcano.
GIF animation of partially collapse of the volcano’s summit crater (image: @simoncarn/twitter)
Stromboli (Eolian Islands, Italy): The lava flow has decreased significantly in intensity during last night, but according to the volcano observatory still remained weakly active today. Judging from webcam imagery, however, it appears it might more or less have stopped by this evening. No other significant changes in the activity at the summit craters – spattering and intermittent explosions from several vents – have been reported. …25 May: The effusive-explosive eruption of the volcano continues and remains essentially unchanged at moderate levels. The lava, keeping the flow active, continues to effuse from the NE crater onto the Sciara del Fuoco and slowly reaching about 400-500 m elevation, i.e. half way down to the sea. … [read more] … [show less] Strombolian-type explosions and spattering continue from several of the summit vents. Incandescent material from the margins and front of the flow slid down along the Sciara del Fuoco and reached the sea.
Etna (Sicily, Italy): Starting from 17:30 local time, volcanic tremor once again started to rise sharply and from around 18:20, intense strombolian activity started at the New SE crater, producing dense ash plumes that rose a few 100 meters and drifted into easterly directions. This activity seems to be still increasing and if continues might well lead up to yet another paroxysm, this time less than 24 hours since the previous one! …25 May: Like clockwork, approx. 48 hours after the previous one, Etna produced a 4th paroxysm in a row with near-identical time intervals from the New SE crater last night. It marked the 25th lava-fountaining episode during 2021. The eruption followed very much the style observed during the previous lava-fountaining episodes: first, from 20:58 local time, strombolian activity resumed at the New SE crater while volcanic tremor began again to rise and its source moved to the area of underneath the New SE crater. … [read more] … [show less] About 1 and a half hour later, activity had increased towards sustained lava fountains from 22:25 on. A tall plume of ash and scoria lapilli drifted ENE. The lava fountain lasted until midnight, when it rapidly ceased.
Lewotolo (Lesser Sunda Islands): (24 May) Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Darwin warned about a volcanic ash plume that rose up to estimated 7000 ft (2100 m) altitude or flight level 070 . The full report is as follows: VA TO FL070 MOV SW OBS VA DTG:24/2250Z to 7000 ft (2100 m)
Krakatau (Sunda Strait, Indonesia): (25 May) Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Darwin warned about a volcanic ash plume that rose up to estimated 6000 ft (1800 m) altitude or flight level 060 . The full report is as follows: VA TO FL060 MOV SW OBS VA DTG:25/0150Z to 6000 ft (1800 m)
Dukono (Halmahera): (24 May) Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Darwin warned about a volcanic ash plume that rose up to estimated 8000 ft (2400 m) altitude or flight level 080 . The full report is as follows: VA TO FL080 MOV NE OBS VA DTG:24/2230Z to 8000 ft (2400 m)
Fuego (Guatemala): Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Washington warned about a volcanic ash plume that rose up to estimated 14000 ft (4300 m) altitude or flight level 140 . The full report is as follows: VA EMS SEEN IN SAT. to 14000 ft (4300 m)
Sangay (Ecuador): Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Washington warned about a volcanic ash plume that rose up to estimated 18000 ft (5500 m) altitude or flight level 180 and is moving at 5 kts in SE direction. The full report is as follows: VA CLDS CONT OBS IN STLT IMAGERY to 18000 ft (5500 m)
Reventador (Ecuador): (25 May) Volcanic Ash Advisory Center Washington (VAAC) issued the following report: VA NOT OBS
Sabancaya (Peru): Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Buenos Aires warned about a volcanic ash plume that rose up to estimated 26000 ft (7900 m) altitude or flight level 260 . The full report is as follows: INTERMITTENT EMISSIONS to 26000 ft (7900 m)
Nevados de Chillán (Central Chile): Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Buenos Aires warned about a volcanic ash plume that rose up to estimated 14000 ft (4300 m) altitude or flight level 140 . The full report is as follows: INTERMITTENT EMISSIONS to 14000 ft (4300 m)
Soufrière St. Vincent (West Indies, St. Vincent): After little more than one month since the last eruption on 22 April, the volcano continues at seismic unrest. A volcanologist Dr. Adam Stinton from the Belmont observatory noted: „Since the morning of Friday 21st, there have been a handful of earthquakes, just around 20-25. None of the earthquakes are large enough to be felt at the moment; the average per day is about 10-15 since the last explosion on April 22nd“. … [read more] … [show less] A near-constant gas and steam venting continues from the summit crater. Satellite-based images confirmed that no actively growing lava dome appears within the summit crater at this moment and there is no indication that the volcano will return to a dome growing phase again. Judging from the attached image, an uplifted area in the inner summit crater may indicate either extruded magma towards the surface or tephra accumulation immediately after the last eruption.
Nyiragongo (DRCongo): Explosive activity continues. Volcanic Ash Advisory Center (VAAC) Toulouse warned about a volcanic ash plume that rose up to estimated 20000 ft (6100 m) altitude or flight level 200 and is moving at 10 kts in S direction. The full report is as follows: ERUPTION AT 20210522/1630Z ERUPTION STILL IN PROGRESS to 20000 ft (6100 m) …25 May: An amazing and first ultra-high resolution satellite image after the eruption shows visible changes at the summit crater.
…25 May: The seismic activity of the volcano quickly intensified after the eruption and continues at elevated levels although lava flows have stopped. The seismic network detected continuous volcanic tremor between midnight and 04:00 local time today indicating magma moving upwards through the volcanic conduits. This may be typical sign for an upcoming eruption. … [read more] … [show less] The strong volcanic tremor at roughly regular intervals has been felt in Goma city by local observers as huge cracks started to appear in the roads and buildings. Huge cracks in the roads and buildings caused by elevated tremor (source: @Melaniegouby/twitter)
…25 May: Sadly, the death toll from the recent eruption rose to at least 20, after 5 people were found choked to death from toxic fumes when they attempted to cross one of the recent and barely cooled down lava flows that had cut through their neighborhood in an area 13 km north of Goma. What gas exactly caused their death was not mentioned, but one speculation is it could odorless carbon dioxide trapped in depressions on the surface of the flow – the slopes of Nyiragongo are infamous for many fissures and ground vents emanating accumulating sometimes deadly concentrations of the highly toxic gas. … [read more] … [show less] Nature of eruption still unclear While the eruption is probably over or at least in a pause, it’s still not clear whether the lava erupted was from a sideways fissure connected with the central conduit that drained the lava lake from the volcano’s summit caldera, or from a new lateral conduit tapping a separate reservoir.
Stromboli’s Sciara del Fuoco this morning with the still weakly active lava flow (image: LGS webcam)
