One of the scientists monitoring the La Soufriere volcano in St. Vincent, which began erupting effusively one week ago, says residents should remain on high alert, but not panic about the situation.
“… in summary, you may have to remain at a high [alert] level for a long time. You need to keep listening out, you don’t have to get overly concerned … What you need to do is that if the volcano goes explosive, essentially, we need to move off the mountain for a certain period of time until it gets rid of all that explosion. And then at some point, you may be able to come back,” Richard Robertson, a geologist, said during an interview over the weekend.
Robertson is among a team of specialists from the Seismic Research Unit at the University of the West Indies (UWI), St. Augustine campus in Trinidad and Tobago that has been dispatched to help monitor the volcano.
Emergency management officials have been using aircraft to monitor the growth of a new dome, which was discovered last Tuesday in the volcano that last erupted in 1979.
The 1979 event, an explosive eruption that took place on April 13, Good Friday, is said to have resulted in the evacuation of 20,000 persons from North Leeward and North Windward. No lives were lost as a consequence of that eruption, which saw thousands of persons spending months in evacuation camps set up mainly in schools and other public buildings.
Robertson, who is a professor of geology at UWI, said that the team has been using information from the National Emergency Management Organisation (NEMO)’s observation flights to come up with estimates of how the dome is growing and basic estimates of its rate of growth.
The information collected so far has shown that there is a new dome growing next to the 1979 dome, located inside the huge crater at the 4,048 foot-high volcano.
“… the growth of the small dome has continued. It seems that it started out at a particular rate, and it’s slightly increased over the days since it started,” Robertson said.
Robertson said that the new equipment installed would help scientists to determine the implication of the rate of growth of the dome for persons living in the areas surrounding the volcano.
He said even if the volcano does not erupt explosively, effusion could continue to the point where the new dome gets so big that “it perhaps gets to the crater wall”.
He explained that the classic example of effusive eruptions is of those seen in Hawaii, where there is the long red lava flow.
Robertson said he did not have good news for Vincentians because given the history of La Soufriere and how it behaved in previous eruptions, an effusive eruption could go on for several weeks or months.
“… which is why we have to remain at the heightened state, which is getting ready for if it goes explosive is because of that — it can go from effusive to explosive in a very short time. And we are very uncertain of how long that time is.”
He said that his team is monitoring to give authorities as much time as possible, should an evacuation order be necessary.
According to NEMO, the alert level remains at orange – the second-highest on the four-color chart, with red, being the highest.
With an orange alert, residents north of Belle Isle and Georgetown have to be prepared to evacuate at a moment’s notice, as an explosive eruption could occur within 24 hours.