By Demion McTair. Updated 5:55 a.m. Tuesday, April 27, 2021, Atlantic Standard Time (GMT-4).
Many people believe that the islands of The Grenadines are made up of limestone, while mainland, St. Vincent is volcanic.
One expert is saying, however, that The Grenadine islands are in fact of volcanic origin.
“The whole of the Lesser Antilles, the Eastern Caribbean, was originally volcanic,” Professor – Geologist, Dr. Richard Robertson said on NBC radio on Monday, while responding to a question from a caller.
“In some cases, like in The Grenadines, the volcanism is so old that it has been covered over, in a sense, by marine deposits because of sea-level change,” Professor Robertson said.
The Grenadines is an area comprising of several islands which are part of the multi-island State of Saint Vincent and the Grenadines.
A small part of the island chain belongs to Grenada and comprises mainly Carriacou and Petite Martinique.
The islands of The Grenadines are located to the south of mainland, St. Vincent.
Mainland, St. Vincent (the largest island belonging to the State of St. Vincent and The Grenadines), where the La Soufriere volcano is erupting is known for its volcanic black sand beaches (though brown sand beaches are found on the southern tip of St. Vincent).
But, The Grenadines area has been known for its turquoise waters and white-sand beaches, a feature often attributed to corals.
Due to that contrast between the beaches on St. Vincent and those of The Grenadines, the latter is often thought of as having no volcanism.
“At one point, the sea level around the Caribbean was much higher than it is now, so then corals developed from that,” Professor Robertson said.
He said that even the islands that appear to be limestone, “they have at their core volcanic materials”.
Even though there are no active volcanos in The Grenadines and the furthest inhabited Grenadine island belonging to the State of St. Vincent and The Grenadines (Petite St. Vincent island) is located some 56.4 miles (90.7 kilometers) away from the La Soufriere volcano on mainland, St. Vincent, some of the grenadine islands have another potential volcanic threat near them.
There is an underwater volcano in the waters north of Grenada called Kick-’em-Jenny, which last erupted in 2015.
This submarine volcano, when erupting, can pose a threat to ships if they get too close to it. Experts say it has the potential to generate tsunamis.
But, the UWI Seismic Research Center says on its website that “While it is probable that large explosions or landslides at Kick ’em Jenny could generate tsunamis, the threat from tsunamis has been largely over exaggerated”.
“Not all eruptions at Kick ’em Jenny will generate tsunamis and not all tsunamis will be large,” UWISRC said.
The Center said:
“Studies show that the worst eruption that Kick ’em Jenny is capable of under any circumstances might generate a wave with an amplitude of 10m in open waters at a distance of 10km from the vent. Waves of this amplitude could be generated only if the volcano began to erupt in water depths of less than about 130m. Currently, the depth to the vent is 268m.”
Meanwhile, Professor Robertson reiterated that all the volcanos on mainland, St. Vincent, south of La Soufriere are dead.