The alert level associated with La Soufriere in St. Vincent was on Tuesday raised to orange, the third highest on the four-colour scheme, as the volcano entered an effusive eruption stage.
This means that magma is oozing from the volcano and is distinct from the explosive eruption such as that of 1979, although one could follow the other.
With the orange alert, residents of the northern third of St. Vincent — from Georgetown to Fancy, in the east, and north of Belle Isle, in the west — have been told to prepare to evacuate at short notice, should such an order be given.
“What is happening now is a serious thing. The volcano is erupting,” Professor Richard Robertson of the University of the West Indies Seismic Research Centre, in Trinidad, told the media by video link.
He said that scientists would try their best to give at least 48 hours warning in the case of an explosive volcano.
“We are trying to make sure you have whatever the time you need to move people out of harm’s way — whether it is 48 hours, 24 hours, whatever time that is. We want to be in a position to give you that and we’ll try as hard as we can to do that,” said Robertson, whose team could be in St. Vincent, bringing additional equipment as soon as Wednesday evening.
“I think you have to prepare for a rocky road for the next couple of months, unfortunately. Prime Minister, I think St. Vincent dodge COVID, but I am not sure you are dodging the volcano, unfortunately,” Robertson said.
Speaking at the same press conference, Prime Minister Ralph Gonsalves urged residents in the red zone to be ready to evacuate at short notice, but emphasised that the alert was not an order to evacuate.
Robertson said that increased activity had been noted at La Soufriere since Nov. 16.
He said that while notifying the public of this is a decision for Kingstown, there had been similar levels of activity at the volcano, in the past, which were not followed by an eruption.
However, there were eight activities on Dec. 23, followed by a quiet period during which no activity was recorded.
Then on Sunday, Dec. 27, the centre’s staff was made aware that a NASA satellite had detected a hotspot in the crater of the volcano.
Therefore, the centre arranged with the National Emergency Management Organisation (NEMO) in Kingstown to visually investigate what was happening.
When the La Soufriere Monitoring Unit, in Kingstown, visited the 4048-feet high volcano on Tuesday, they discovered that there is a diffusive emission of magma extruding out of the volcano.
“What the guys discovered when they went up there today is that just north of where you have the fumarolic activity … where there was a pre-existing lake, there was an explosion and a black mass of rock formed that area. And from what we have seen of it, it’s steaming,” Robertson explained.
“And from what we are seeing, there is currently, in our conclusion, an effusive eruption ongoing at Soufriere where, essentially, magna is coming slowly out of the earth and building another dome,” he said.
The specialist said that this dome, called a satellite dome, is growing next to the dome that formed after the 1979 eruption of the volcano.
He said that scientists at the centre were working with NEMO to augment the monitoring system.
“What is happening now is similar to what was happening in 1971-1972,” he said, adding that unlike then, there is no lake in the volcano.
“But you have the same kind of mass growing on the side. The mass is currently confined in the crater of the volcano. Because of the configuration of the crater, a lot of the hazards, as it presently stands, are in the crater itself and on the immediate rim of the crater. So the hazard would be from the rock itself, that is simply coming out and the rock is gonna be [hundreds of degrees Celsius] hot, so you don’t want to be close to it when it’s growing.
“If you think of it as a big truck dumping a set of stone and is just dumping the stone but the stone is coming from below … and as it comes out, it is bringing with it the gases that come out and the steam that you are seeing is the gasses that are coming out.”
Robertson said that a lot of the gas is sulphur-rich and most of it, when it mixes with the atmosphere is not going to cause as much harm.
“It’s probably if you’re on the crater rim it’s going to be really difficult to breathe because some of the sulphur, some of the constituents of that gas … is smelly, but also, it dries out your respiratory system, makes it difficult to breathe.
“So the point is, on the crater rim, not a good place to be, but as far as this mass stays in the crater, it is fairly a contained threat to the people of the flanks of the volcano.”
Robertson said that his centre would want to monitor the rate at which the mass is increasing in size.
“Because as it expands and increases in size … it can spill over into surrounding valleys,” he said, adding that the closest valley is Larikai, an uninhabited area of the country, north of Chateaubelair.
He said that the other threat is the possibility of something else happening.
The scientist warned against unofficial persons visiting the dome of the volcano, saying that in addition to the dangerous emissions, rapid change at the crater is a serious threat.
Robertson said that he knows that everyone would want to visit the crater now.
“Don’t do it. It’s a bad idea… I’ll say this about volcanoes, no matter what people think, and La Soufriere is one of them: whatever you like, the volcano, when it does what it does, you take action, otherwise it is too late for you. So those who go on the mountain and want to look in and get overcome by gasses – I hope they are just sensible enough to not put themselves in harm’s way. So I suspect that anybody that is sensible, when they go and see what they want to see, they would quickly realise that it’s a bad idea and turn back, at the very least.”
He said the volcano either erupts effusively as is happening now, or explosively, as in 1979.
Monitoring is important because while in 1971 there was an effusive eruption followed by years of quiet then the explosive eruption in 1979, it is possible for both to happen closer to each other.
“So that is one of the things we have to look at — if it is going to move from effusive to explosive, which makes it a bit more dangerous.”
He said that a lot more data is needed to reasonably predict if the eruption will progress from effusive to explosive.
“What people need to understand is that once an eruption starts at Soufriere or anywhere else, one of the things that scientific groups would try to do is to collect more information, look at it even more closely. So we put more instruments on, we use all kinds of techniques, because what we’re trying to look at is to see how it moves from where it is now to the next stage.”
He said that in the coming weeks or months, scientists will evaluate whether the volcano is moving from one stage to the next and try to give enough warning so that residents could take action that they might need to.
“And we are hoping that within the time you have before it goes to explosive we will give you enough warning to take the action that you need to, which is essentially getting people out of harm’s way, which is the main thing.”
Robertson, however, said that the eruption could remain just effusive.
“And in the best case scenario [one hopes] that it oozes out and eventually it stops and it goes to sleep for the next — of course, it is going to wake up at some point in time again, but still, we wouldn’t have to deal with it immediately,” he said.
The centre is expected to deploy a team to St. Vincent and the team could arrive as soon as Wednesday, Gonsalves said.