Soufriere is resting, but remain on the alert! – Scientist
The Soufriere volcano is not showing signs of unrest at the moment, but persons must remain alert as nature sometimes throws curved balls.
Lloyd Lynch, lead Scientist monitoring the volcano made the point this week while speaking on NBC Radio’s Eyeing La Soufriere program.
Lynch, who is attached to the University of the West Indies Seismic Research Unit (UWI-SRC), said volcano unrest means increasing activity above background activity, and that has not been the case in the last few weeks.
He said that when a volcano is in a state of dormancy, there would sometimes be two to three earthquakes a month (background activity) and unrest looks like 10 to 100 earthquakes a day and degassing at the crater.
Lynch said that the volcano is showing declining trends with the odd seismic event only strong enough to get to the Wallibou station. He however noted that last weekend “was a very busy weekend for lahars with 11 lahar signals on both east and west side.”
He said they need helicopter support as safety is their primary concern and it would be useful to fly over the top of the volcano, something they plan to do over the weekend of June 21.
Lynch also noted that persons a greater than usual discharge of steam from the volcano last weekend need not worry as that was because rainfall had penetrated certain points at the top of the volcano that were still hot.
He said the water touching these points created explosions of steam as the areas below the surface are hotter than the boiling point of water.
“In the aftermath of the eruption, a lot of hot debris spewed over various locations inside the crater and the rainfall, remember this is material that is very hot, it may be cool at the surface at the first few inches, then you need to go down about six to nine inches and it is hotter than the boiling point of water.
“So excess water will get down and is converted to steam. So it is just a matter that the rain fall is converted to steam by very hot material that has been precipitated inside and outside the crater,” Lynch explained of the gas people said they saw over the weekend.
He said this is “very normal” and people must not be fearful.
Lynch said they met persons in Richmond who were expressing concerns about new vents opening up “…but that is not the case…”.
The lead scientist said that in the early stages of the eruption, they lost monitoring capacity at the summit of the volcano so they have not been able to monitor activity that is taking place inside the crater.
They also lost the monitoring stations at Wallibou, Fancy and Owia and that has compromised their ability to properly monitor earthquakes but the scientists are working on setting up new sites.
Lynch however noted that they have some monitoring capabilities and can locate some earthquakes and they do not expect any large eruptions that can affect the populated areas.
Lynch noted that before the actual explosive eruption on April 9, there were a number of earthquake swarms on April 5th, March 24th and also in November 2020 and that has not happened since.
But he added, “nature can throw curved balls and we need to be very careful and look at the risk associated with the deposits and damage to the electrical grid and so on,” he stressed, adding that La Soufriere is a lot less dangerous that when it was in its explosive phase and he is of the view that the eruption may have ended, but there is some element of uncertainty.