Between a Rock and a Hard Place

Lesser Antilles

Science snaps (2): Soufrière Saint Vincent

Soufrière Saint Vincent is youngest volcanic centre on the Caribbean island of St Vincent. A stratovolcano some 1,230m in height, La Soufrière has erupted five times in the last three hundred years, most notably in 1902 when 1,680 people were killed. The explosive volcanism here is the surface manifestation of the slow, westwards subduction of the American plate beneath the Caribbean plate, and is part of the 750 km-long volcanic chain of the Lesser Antilles.

The image below shows two views of the summit crater either side of a VEI 3 eruption in 1979. The most striking difference between the two photos is the disappearance of the crater lake; prior to the 1979 eruption it was possible to row out to the lava dome to take samples! Although the blocky andesitic lava dome (~ 130m high and 840m wide) appears in both images, it was in fact destroyed in the 1979 eruption, with the current pile of lava representing new growth. Fumerolic activity was higher in 1972, though the present-day dome does show evidence of gas-venting on one side (aptly, La Soufrière is French for The Sulphurer). Monitoring of the volcanic system on St Vincent is carried out by the Seismic Research Unit of the University of the West Indies.

sourfriere

Soufrière Saint Vincent, Lesser Antilles. Two images taken either side of a VEI 3 eruption in 1979.