(Montserrat)
How it started? Eruptive activity began on 18 July 1995 from several steam vents forming a NNW line across the NW side of Castle Peak Dome. These vents later coalesced to form a single, large vent and a second major vent opened on the SE side of the crater floor on 28 July.
Phreatic explosions with associated steam and ash columns to 3 km height continued for 4 months, with cold base surge ash clouds from the largest explosions on 21 August, 31 October, 4 and 9 November engulfing the island's capital, Plymouth, causing darkness for up to 30 minutes on each occasion and producing ashfalls of a few mm 5 km downwind. The erupted ash was andesitic in composition. Sulphur dioxode production averaged 300 tonnes per/day, with maxima associated with vigorous steam emission events. Volcano-tectonic earthquakes dominated seismicity.
Major events:
a) The onset of phreatic volcanic activity at the Soufriere Hills volcano, Montserrat, on 18 July 1995 followed a three-year period of heightened volcano-seismic activity beneath the island.
b) Phreatic explosions gave way to continuous eruption of juvenile andesitic magma in the form of a lava dome on or around 15 November 1995. Magma production rate has varied, leading to changes in eruptive style.
c) An explosive eruption on 17 September 1996 followed a period of enhanced dome growth and large-scale gravitational collapses from its eastern flank.
d) Increasing dome volume during early 1997.
e) Sustained high magma production rate since June 1997 has led to three periods of major gravitational dome collapses followed by explosive eruptions.
f) Dome growth restarted in October 1997 and continued as of December 1997.
g) A total of 9242 seismic events recorded since 1995; hypocentre distributions suggest a minimum depth of about 5km for any substantial magma body
h) From November 1995 to December 1997 a total volume of 246 x 10 6 m3 of andesitic magma erupted, partitioned into 93 x 10 6 m3 of the dome, 125 x 10 6 m3 of pyroclastic flow deposits and 28 x 10 6 m3 of explosive ejecta.