Soufrière St. Vincent volcano: Eruption Update

Soufrière St. Vincent volcano update: vigorous eruption sent ash up to 35,000 ft this morning

The volcano produced another powerful eruption this morning at around 06:37 local time as confirmed by Volcanic Ash Advisory Center (VAAC) Washington and also by local observers in social media.
A spectacular dense and dark ash plume rose several kilometers above the summit crater up to troposphere boundary to an altitude of 35,000 ft (10,700 m).
The ash column was seen from the Jade Mountain Resort located on Saint Lucia Island about 60 km to the north as visible in the attached image.
Today's volcano explosion commemorates it's significant eruption exactly 42 years ago.

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Soufrière St. Vincent volcano update: eruption calms down a bit, but risk of new explosions remains high

Fortunately for the island, no new major explosions have occurred during the past 12 hours and the volcano has been a bit calmer, with "only" venting of small to moderate ash.
However, the risk of new large explosions remains high. The University of the West Indies (UWI) monitoring the situation detected a change in seismicity: "The pattern of seismic activity changed again, with the end of the episodes of high-amplitude tremor 2-8 hours apart."

From the latest update posted on Twitter:
"Three episodes of tremor have been recorded since 6am, two of them lower-amplitude and the third, at about 5pm, was high-amplitude.
"The episodes continue to coincide with periods of enhanced venting or explosive activity.
"Observations made indicate that pyroclastic density currents (PDCs) had descended several valleys on the southern and western flanks of the volcano and had reached the sea at Morne Ronde, Larikai and Trois Loupes Bay.
"Extensive damage to vegetation was noted in an area extending from Larikai Bay to Turner Bay on the west coast.
"No other areas along the coast had been affected by PDCs but villages located on the eastern flank of the volcano had been affected by heavy ashfall.
"Explosions and accompanying ashfall, of similar or larger magnitude, are likely to continue to occur over the next few days with the chance of PDCs occurring.

Link: Visit the International Volcanic Hazard Health Network for volcanic ash information resources: http://ivhhn.org/information10"

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Soufrière St. Vincent volcano: massive explosion at night, dangerous hot avalanches reported

Another huge explosion occurred from the volcano in the early morning hours at 4:15 am according to Civil Protection and the University of St. Vincent.
Pyroclastic flows were also reported - these are very dangerous, glowing turbulent avalanches of rock fragments and gas likely caused by collapsing parts of the eruption column that can travel many kilometers and destroy everything in their path. There is no data yet on how far and where exactly the pyroclastic flows traveled. We expect more information to come out in the near future, though.

The dome is confirmed completely destroyed. An important question to find out is whether the magma that has now erupted explosively is different from the one that had been building the dome during the past months, and how much of it is still left able to erupt in more explosions.
A speculation is that the previous magma that had been building the new (now gone) dome until recently was actually older, more or less degassed magma left in the conduit from the previous eruption in 1979, gradually pushed out by a new batch of gas-rich magma rising from depth, and erupting now.
The other possibility is that the dome had grown sufficiently to seal the conduit temporarily, causing magma underneath to form trapped gas bubbles, with increasing pressure, until it exploded, throwing the dome out like a champagne cork.
The sudden release of pressure would then open the upper conduit and allow gas-rich, foamy and viscous magma to rise quickly and erupt explosively.
A combination of both processes is a likely possibility as well.

Live updates from St. Vincent:

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Soufrière St. Vincent volcano (St. Vincent Island, West Indies): heavy ash fall covered entire island

A heavy ash fall has blanketed the Saint Vincent and the Grenadines and affecting the entire island by extremely poor visibility.
Strong ash and lapilli fall is occurring as far from the volcano as Argyle International Airport some 20 km away as National Emergency Management Organization (NEMO) reported.
A fresh scoria was also present in the ash collected at Rabacca river at about 7,4 km from the volcano.
More than 16,000 residents in "red zones" were urged to evacuate.

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Soufrière St. Vincent volcano (St. Vincent Island, West Indies): dramatic changes to crater

An amazing recent satellite image shows dramatic morphological changes in the volcano's summit crater: the first two powerful explosions on 9 April completely destroyed the 1979 and 2020-2021 lava domes and left a new deep vent.

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Soufrière St. Vincent volcano (St. Vincent Island, West Indies): powerful eruptions continue with huge ash clouds

An another vigorous explosive eruption occurred at 13:30 UTC yesterday detected by the satellite Copernicus.
The series of the massive eruptions continue at high levels and are characterized by impressive ash clouds that extended over the Atlantic Ocean advancing the Iberian Peninsula! Satellite-based measurements of SO2 concentrations in the atmosphere show the huge SO2 plumes ejected by Soufrière St. Vincent volcano.
A spectacular dense and dark ash plume reached up to 40,000 ft (12,000 m) altitude that drifted towards the Barbados and further spread about 3,000 km to the E-NE of the volcano.
The warning bulletin of the National Emergency Management Organization (NEMO) urge the residents with respiratory problems to take necessary precautions to remain safe and healthy.

Extending ash cloud over the Atlantic Ocean continues to advance the Iberian Peninsula (source: @m_parrington/twitter)

@CopernicusECMWF Atmosphere Monitoring Service @ECMWF total column SO2 forecast initialized 10 April 12 UTC with assimilated #Sentinel5P obs showing #LaSoufriere plume transport across Atlantic (assuming 500hPa injection height). Visualized by @Windycom https://t.co/WfAgw3vqA8 https://t.co/WvdpDM8U96 pic.twitter.com/34k0lAREux

— Mark Parrington (@m_parrington) April 10, 2021

Huge eruption column visible from satellite (source: @EdPiotrowski/twitter)

Another huge eruption of the #LaSoufriere #volcano this morning. You can see the massive plume of ash and the shock wave emanating from the crater. Incredible! Imagery via #GOES16 pic.twitter.com/Z63PnR2Oi6

— Ed Piotrowski (@EdPiotrowski) April 11, 2021

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Soufrière St. Vincent volcano (St. Vincent Island, West Indies): second strong explosion in the afternoon

A second strong explosion occurred this afternoon, around 2:45 pm, apparently similar in size as the one from the morning.
Volcanic Ash Advisory Center Washington reports an ash plume reaching 20,000 ft (7 km) altitude and moving SE. Images taken from the island confirm a tall ash column rising at least 4 km according to estimates from the volcano observatory.

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Soufrière St. Vincent volcano (St. Vincent Island, West Indies): massive eruption sends ash to 20,000 ft

A strong explosion occurred this morning at the volcano at 08:40 am local time. The eruption produced an ash column that rose several km above the active lava dome.
The Belmont volcano observatory indicated the height of the ash plume as high as 8 km (24,000 ft), while the Volcanic Ash Advisory Center of Washington issued alerts of ash to 20,000 ft. The plume drifted east from the island.
Ash fall occurred at the Argyle International Airport and all persons in the red hazard zone, which comprises the northern third of the island, were asked to evacuate immediately. In Georgetown alone, 1,700 people needed to leave their homes.
Video of the eruption:


Change in eruptive behavior
This marks a change in the eruptive style of the young lava dome, from growing rather calmly by effusion of viscous lava towards a much more dangerous mix of effusive and explosive eruptions.
Explosive activity so far had only been minor only, even though videos and images taken the day before (attached) show an increase in degassing, moderate ash venting and glowing rockfalls from the dome, suggesting that something was changing. In any case, the interesting question is what caused this apparent relatively sudden (if not brutal) change. It is not easy to answer this without closer investigation of the eruption products and other parameters only scientists on location have access to, but could help reveal the cause of today's explosion.
One obvious possible reason could be the arrival of more gas-rich magma, which should reflect in a different composition of the eruptive products. Or was it simply that gas-rich parts of the dome's interior, or even trapped pockets of gas had slowly grown beyond a threshold, literally blowing off the cork today?
Certainly, the fact that volume of the accumulated lava in the dome has continued to grow facilitates the process of trapping pockets of gas or gas-charged hot rocks inside. In fact, both explanations can be at work, but we can so far only speculate on this.
It also follows a pattern frequently observed at dome-building volcanic eruptions, such as at Sinabung since 2013, or as a geographically very close example, Soufrière Hills on Montserrat during 1995-2000, but also many others. In the first stage, the eruption is mainly effusive and often brusquely turns to a mix of effusive and explosive activity.

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Soufrière St. Vincent volcano (West Indies, St. Vincent): effusive eruption continues with series of seismic swarm

The effusive eruption of the volcano continues characterized by the actively growing lava dome.
On 5 April at 06:38 local time a swarm of small volcano-tectonic earthquakes began to occur as the West Indies Seismic Research Centre's (UWI-SRC) seismic station recorded. The quakes increased gradually until about 08:30 local time as continued at steady rate after. The earthquakes were located beneath the volcano's summit at 6 km depth. The largest event reached the magnitude of 3.5 that was felt by residents living close to the volcano. The swarm is related with an elevated seismic activity at the volcano occurred during 23-26 March as a period of volcano-tectonic earthquakes was detected.
The Volcano Alert Level remains at Orange.
Source: University of the West Indies Seismic Research Centre volcano activity update 7 April 2021

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Soufrière St Vincent volcano (West Indies): lava dome continues to grow slowly

The lava dome continued to slowly grow during 17-23 March, expanding to the N and S. A team visited the dome on 19 and 23 March to make observations, take measurements, and maintain monitoring equipment.
Gas-and-steam continued to rise from the top of the dome as well as along the contact between the old and new domes.
As of 19 March the dome was 105 m tall, 912 m long, 243 m wide, and had an estimated volume of 13.13 million cubic meters. The Alert Level remained at Orange (the second highest level on a four-color scale).

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Soufrière St. Vincent volcano (West Indies, St. Vincent): twice length and volume of new lava dome since last update

The effusive eruption of the volcano continues characterized by the actively growing lava dome.
On 19 March the University of the West Indies Seismic Research Centre (UWI-SRC) monitored the volcano by drone to detect of physical changes of the new lava dome.
The central active vent continues to feed the growing lava dome in north-west and south-east direction. The extruded lava dome is currently about 105 m tall, 243 m wide and 921 long (511 m on 4 Feb) with a volume of 13.13 million cubic meters (5.93 million cubic meters on 4 Feb). Its length and volume is almost twice since the last update on 4 February.
The observations confirmed ongoing sulfur dioxide (SO2) emissions concentrated on the top of the new dome as well as at the contact with the 1979 lava dome.
Source: University of the West Indies Seismic Research Centre volcano activity update 22 March 2021

Latest drone video taken of the new dome at La Soufrière, SVG on March 19th, 2021. Its approximate dimensions are 921m in length x 243m width and 105m in height. The volume of material ejected is now estimated to be 13.13 million m3. The Centre and NEMO SVG continues to monitor. pic.twitter.com/BkGJ1olq96

— UWISeismic Research (@uwiseismic) March 21, 2021

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