KINGSTOWN, St Vincent (CMC) — The Argyle International Airport (AIA) is scheduled to be reopened on Monday even as the scientists monitoring the La Soufrière volcano said that explosions with accompanying ashfall, of similar or larger magnitude, could restart in the future, impacting St Vincent and neighbouring Caribbean islands.

The airport was forced to close because of ash generated from the April 9 eruption of the volcano and the chief executive officer, Corsel Robertson, said that due to significant ash deposits all operations at the Argyle International Airport, have been suspended, until 4:00 pm (local time) on Monday.

 “The facility is undergoing rigorous cleanup of runways and apron to accommodate humanitarian flights as a priority,” Robertson said and the civil aviation authorities here said that the James Mitchell Airport, on the grenadine island of Bequia, will remain closed until April 19.

They said the Canouan, Union Island and Mustique airports will remain operational from 9.00 am to 5.00 pm only to accommodate special flights with prior permission.

Meanwhile, the Seismic Research Centre (SRC) of the University of the West Indies (UWI) says the swarm of long-period and hybrid earthquakes continued at La Soufrière and that the rate of occurrence of these earthquakes dropped significantly on Friday night “and has remained near-constant since”.

“No episodes of tremor have been recorded in the last 12 hours,” the SRC said, adding that a new crater, measuring approximately 900 metres north to south and at least 750 metres east to west, has been formed.

“The crater is thought to be at least 100 metres deep and is centred in the south west sector of the Summit Crater. Within the new crater, there are several vents, but only one can be identified clearly.  Other vents, as indicated by the ash and steam plumes are located in the northern part of the new crater,” the SRC added.

It warned that the volcano “continues to erupt although explosive activity appears to have ended at this time”.

“Its current pattern of seismic activity may indicate growth of a lava dome, but this has not yet been confirmed.  Explosions with accompanying ashfall, of similar or larger magnitude, could restart in the future impacting St Vincent and neighbouring islands,” the SRC said in its early bulletin on Saturday.

Volcanologist, Professor Richard Robertson has said that the ongoing eruption of La Soufriere is expected to be bigger than in 1979 but has only so far produced about one-third of the new material that the volcano did 42 years ago.

“Even if we have a week of nothing happening, and just earthquakes, just VT (volcano tectonic) earthquakes that we are having now, I don’t think we would say that it is finished, for a number of reasons,” he said.

Speaking on the state-owned NBC Radio on Friday, Robertson, the lead scientist, said that persons being affected by the eruption must bear in mind that, historically, the volcano has always erupted for longer than a week.

Further, the current eruption is expected to be more like 1902, which was bigger than in 1979, even as the on-going eruption has only produced one-third of the “new material” the volcano did four decades ago.

Second, the amount of energy that this volcano had at the beginning suggests “it has a lot more down there to come out,” he said.

Robertson said that excluding the 1979 and 2020-2021domes — both of which the volcano has already destroyed — his team estimates that the volcano has only released a small portion of the fresh magma inside.

“It is only about 20 million cubic metres, if any that has come out as fresh material,” Robertson said, noting that in 1979, the volcano put out upwards of 60 million cubic metres of material. In 1971, when the volcano erupted effusively, it put out something around 60 million cubic metres.

“So past eruptions which started less vigorously have produced new material that was much more, so to think now, when we have only had a small amount of new material put out that it is finished, I think we would be totally wrong,” Robertson said.

“So we have a little time yet. I know people would love it — I would love it to finish, too. But the reality is that we will have to deal with this thing for a little while. It might be that the way we would have to deal with it is by having to get accustomed to periodic explosions. I hope that is what it is, and explosions that produce ash that goes towards the coast, that goes off coast and drop the ash in the sea, but there is no guarantee that that would happen.

“At the very least, what is going to happen, if it does that, it is really going to damage and destroy a lot of the property and land on the volcano itself,” Robertson said.

La Soufriere erupted explosively on April 9, after three months of effusive eruptions.