Killer volcano warning
Scientist warns La Soufriere behaving more like 1902 eruptionMonday, April 12, 2021
KINGSTOWN, St Vincent (CMC) — A regional volcanologist yesterday warned that the ongoing eruption of La Soufriere volcano in St Vincent is in keeping with the events surrounding the 1902 eruption, which claimed 1,600 lives at a time when early warning systems and evacuation capabilities were not as advanced.
Speaking on the State-owned NBC Radio, Professor Richard Robertson, the lead scientist monitoring the volcano, said that while most people know of the 1979 eruption, what is currently happening at La Soufriere is more akin to a century ago.
“The activity pattern we have currently is more similar to a 1902 type of eruption of that kind of scale, rather than a 1979 scale. The people who lived through 1979 know the kind of eruption we have had,” Robertson said.
“What does that mean? It means, unfortunately, that it is likely going to cause more damage and destruction to St Vincent, but it also means that there will always be a safe place in the south of the country, which might have a lot of ash every now and then, but you can still sustain life and limb, and it would not — which is what we all worry about — get so big that it destroys the whole country. That currently doesn't seem to be the case.
Robertson's comment came as he warned that pyroclastic flows could become a major issue. Pyroclastic flows resulted in many of the death recorded in 1902. No one died as a result of the 1979 volcanic eruption.
The volcanologist, who is based at the Seismic Research Centre of the St Augustine Campus of The University of the West Indies (UWI) in Trinidad, said that the monitoring team now has evidence that there have been pyroclastic flows.
When a pyroclastic flow occurs, a mass of superheated air and volcanic material, rather than rising into the atmosphere, collapses on itself, rushes down valleys, and destroys everything in its path.
“So if you visualise that you have something is shooting down the mountainside, it is going faster than [Usain] Bolt, … sometimes 200 kilometres per hour… Fortunately, it stays in the valley, but sometimes it spreads out to the surrounding, higher paths,” Professor Robertson said.
“But when it meets anything in the valley, whether it is trees, cars, buildings, it has enough force that it pushes them out of the way, destroys them, and it keeps going. It has so much force, so much energy, and so much heat than when it gets to the coastline … it is so hot that it then boils the top of the sea … and it then creates a cushion of bullets that it then shoots across the sea even faster, and it only runs out eventually,” he explained.
Robertson said the flows that the team had observed might have been from one of the previous explosions that has occurred since La Soufriere erupted on Friday, and not necessarily the activities Saturday night.
“So far, it seems that we had not observed them from the observatory, but there is evidence that they have occurred,” he said, speaking from the monitoring station in Belmont, near Rose Hall, which offers a commanding view of the volcano.
“There is one on a video that we have access to that happened on the leeward side,” he said, speaking of his team's evidence that pyroclastic flows had occurred.
“That tells us that, in addition to the venting that's happening, these things can happen, and are beginning to happen, which means that the volcano itself, the mountain, Soufriere, and any communities there, not only they had to survive the heavy ash, but now they have the potential of being destroyed by these flows that go down the mountainside,” Robertson said.
“These things are not like the ash that damage things by the weight; these flows really are moving masses of destruction,” said Robertson, who warned that the roofs of even more buildings could collapse under the weight of volcanic ash.
“They destroy everything in their path,” Robertson said of the pyroclastic flows, adding “if you have the strongest house in the world, they will just bulldoze it off the ground.
“So, it means that the amount of devastation you are going to have on the volcano itself, when this thing has stopped and we go back and see, is going to be significant, not only because of the ash, but because of these flows that could go down the mountainside.”
The whole of St Vincent, some of the Grenadine islands, as well as neighbouring countries are blanketed in ash, and Robertson warned that the volcano is not showing signs of letting up.
“The activity that we are having now, there is no indication on the instrumentation that it is waning... that it is going towards the end.
“So, I would love to tell you that this is all we have to sustain, this last couple days, but I can't tell you that. It is likely that at some time it would quiet down and there will be a break so that we can recover a little bit more. But don't be surprised if after the break it picks up again, and then we have another period like this, and then there might be another break, and it picks up again,” he said.
Meanwhile, The UWI has described as “fake news” reports being posted on social media that it has issued an “Emergency Orange for Grenada, meaning that an underwater eruption is possible within the next 24 hours”.
Yesterday, the director of the Seismic Research Centre Dr Erouscilla Joseph said that Barbados should be prepared for ash emanating from the volcano “for days to weeks”, in the first instance.
“Unfortunately the worst-case scenario is that this can go on for weeks because of the changes in the dynamics of the system. We just have to kind of keep monitoring the seismicity associated with the volcano and advise based on that,” she told a news conference at which Prime Minister Mia Mottley urged Barbadians “not to panic” as a result of the tremendous amount of ash falling on the island since the volcano began explosive eruptions last week.
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