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Persons in south of St Vincent are safe and likely only to experience ash falls

Persons in south of St Vincent are safe and likely only to experience ash falls
Professor Richard Robertson

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Residents of the southern half of St Vincent and those who have evacuated out of the danger zones are safe and expected to mainly be affected by ash falls from the erupting La Soufriere. However, those who remain close to the volcano are endangering their lives.

Lead scientist monitoring the volcano, Professor Richard Robertson of the University of the West Indies Seismic Research Centre (UWI-SRC) gave this assurance today, while addressing a press conference, shortly after explosive eruptions began at La Soufriere.

“It is mainly the ash that will affect the green and yellow areas, not the things that will kill people like on the volcano itself, like the pyroclastic flows and surges,” he said.

The explosive phase of this eruption of La Soufriere began at 8:41 am and a vertical explosion plume which went up an estimated 10 kilometers (32,800 feet) was given off, Robertson said.

A second explosion at the volcano took place at about 3 pm, with the ash plume going about 4 km (13,000 feet) into the atmosphere.

“The batch of magma that had been trying to come up for the longest while is either right at the surface or quite close to the surface and overnight it punched through. And it has cleared the throat of the volcano. After the explosion, the tremoring and shaking went on for about 40 minutes or so…. It continued roaring for a little while…. After that, within an hour, it has got a bit quiet,” the Vincentian volcanologist said.

He however warned that this explosive phase of the eruption is likely to go on for days or weeks.

“We would not be surprised if this continues for the next few days, next few weeks. We hope it is one of the smaller eruptions and does not go on for longer than that.”

“…It is possible that we can have more explosions like these. There is fresh magma, fresh material, gas-rich enough to cause an explosion, right, close at the surface. Once that is there, it could generate another explosion.”

He said it is possible that subsequent explosions could go higher and carry plumes higher in the atmosphere than the first one did.

“The areas that would be most affected would be the volcano itself – possibility for pyroclastic flows and surges on the volcano itself; the red areas, the peripheral orange areas in terms of pyroclastic flows. But the rest of St Vincent is probably going to be mainly affected only by ash. Most of the ash is going to stay in the northern part of the country, so I would be surprised if a lot of ash gets to the green and yellow areas even. But that mainly depends on the wind direction,” Robertson said.

“Wherever the wind takes it, it goes,” he said.

“Most of the times, luckily, the winds go either to the east or the west. The upper level winds go off to the west and the lower level winds to the east. But sometimes, the wind comes to the south. If that happens when you have one of these explosions, the wind comes to the south. If you have a really big explosion, and the spread (ash plume) is big enough over the volcano, the spread can be wide enough that the ash gets to the south. Those are the two ways in which the ash gets to the south,” the volcanologist explained.

“But we are into an explosive phase so it is necessary for us to watch, monitor it, see what it is indicating….”

He said his team will be collecting more data and trying to analyse them, and trying to track this explosive eruption.

“Residents of the south should expect some ash every now and then, but once you are off the mountain, you should be good. If you are one of those persons who are still on the mountain. The first bang is not necessarily the biggest bang this volcano will give.  You would have experienced the first one if you were there still… but I would suggest that you move south,” Robertson warned.