Activity at the Soufrifère Volcano, St Vincent, West Indies, in October-November 1971

Abstract

THE Soufrière Volcano in the north of St Vincent last erupted in 1902–03 (refs. 1, 2). This eruption was extremely violent: an estimated 1.4 km³ of pyroclast flow and fall was emitted, devastating the northern third of the island and killing 1,565 people. After this eruption, a lake was re-established in the summit crater, and since 1910 the lake water seems to have remained constant in level to within a few metres and in temperature to within a few degrees. The presence of fumaroles on the lake bottom is postulated to account for the fact that the lake temperature, which was measured regularly from 1946–1952, remained at about 4° C above the expected from the ambient air temperature³. Apart from this and since the occurrence between November 1945 and February 1946 of a swarm of local earthquakes⁴, several tens of which were felt around the flanks of the volcano, the Soufrière remained dormant until October 1971.