By: Staff Writer
April 6, 2021
The top geologist on the ground in St Vincent and the Grenadines (SVG) warns residents around the La Soufriere volcano to be prepared for something “nastier” to happen other than the mild earthquakes and effusive eruption ongoing now.
Dr Richard Robertson, professor of geology and past director of the University of the West Indies Seismic Research Centre (UWISRC), speaking on a YouTube broadcast, said: “Since about 6:30am, April 5, we had a swarm of volcano tectonic earthquakes started at the volcano, the numbers and managers have increased until about until about 830, and they’re continuing, it’s continuing at a fairly steady rate.”
Despite the increase in earthquakes, the National Emergency Organisation (NEMO) have still not implemented its evacuation plan and has not elevated its warning level to red from orange.
The last time the La Soufriere volcano erupted was on April 13 Good Friday, 1979. That eruption resulted in no casualties due to advanced warning. However, some are now believing history will repeat itself with another April 13 eruption, since the Good Friday prediction did not come through thankfully.
The 1979 eruption happened after 10 months of mild premonitory activity. A series of strong vertical explosions between 13 and 26 April generated ash falls, pyroclastic flows and mudflows.
The current effusive eruption has been monitored since last year November for increased volcanic activity.
Dr Robertson also said: “The largest earthquakes so far in the swarm occurred at 9:20am, which had a magnitude of 3.5 and it was felt by people living close to the volcano.”
“Now, this swarm of VT (volcano-tectonic) quakes having been located at a depth of around six kilometres below the summit of the volcano, this is slightly deeper than the VT activity, which was recorded between the March 22 and 25- These were located at depths of about three to five kilometres, which is slightly deeper.”
He further went on to explain that VT earthquakes are indicative of magma trying to get up to the surface and that and this push increases the frequency of the earthquakes and may raise the likelihood of an explosive eruption.
Dr Robertson also said that since these VT earthquakes are happening “deeper” than previous ones earlier in March, this indicates that there is pool of magma right at the top trying to get out. He added: “Now, why that is important is because we know that diffusive activity that’s happening and the magma that’s there obviously doesn’t have enough energy to become explosive, just simply oozing out more at the surface at the top.”
He went on to say that if anything causes that pressure to increase around the magma at the top there is a “possibility” that it could cause explosions of magma to come out of the volcano.
Dr Robertson also said: “VT earthquake activity is one of the signs we look for, for an indication that this volcano is wanting to go to an explosive activity.”
Dr Robertson further warned that people in the orange zone and the immediate red zone of the earthquake should be seriously considering their evacuation plans in the event an eruption happens. He said: If it goes explosive they would have to move south. If they don’t know by now they should start finding out where are the shelters, or do you have a plan individually to go and stay with someone.
“So what people should be doing, educate yourself, listen out to the sources of information, know what to do, when to do it, know who you are, to listen to where you have to go all of those kinds of things, plans readiness heightened state of alert. Other than that go about your life as you as you would normal in given that you live on a volcano on a volcanic island that could be explosive. Other than that you need to be aware, you need to be prepared in case something nastier than what was happening.”