Lava dome madness continues, and perhaps my fascination of late with lump-headed volcanoes has made me easy to find? But that is alright, because seeking out lava domes has taken me (virtually) to some pretty exciting places. Jesper “Volcanomaniac” Sandberg spotted me first on Soufrière Hills on the Carribbean island of Montserrat, and Leslie “the Bloodhound” Gompf joined us the next day after taking a brief detour through Japan. (some gorgeous old domes there, but that’s another post for another day)
Soufrière Hills’ story is in a lot of ways similar to Pelee’s. Both are located in the West Indies, though Montserrat was settled by England instead of by France, as was Martinique. Both volcanoes are of the same basic rock composition..andesite and basaltic andesite; though Soufrière Hills also includes a higher percentage of dacite than Pelee. Dacite is a felsic extrusive rock that is intermediate between andesite and rhyolite and seems to be a common thread among volcanoes that form lava domes. Basalt and picrobasalt are also found in both, though more is present at Soufrière Hills. This suggests some interesting melting and mixing going on beneath both volcanoes The people of Montserrat and Martinique both had come to regard their local volcanoes as “mostly harmless” even though Pelee had experienced several periods of eruptive activity after Europeans settled there. The people of Montserrat had never seen Soufrière Hills blow its top…that is until 18 July, 1995.
Earthquakes seemed to have been occurring at thirty-year intervals throughout the 20th century, but then the mountani awoke with rumblings and smaller gas explosions at the summit. In August, activity increased with phreatic eruptions and lahars. By this time, Plymouth, the island’s capital city, had been evacuated, , and an influx of seismologists and volcanologists and their equipment had arrived at Montserrat’s behest to monitor the situation. The explosive eruptions continued for the next four months. By the end of November, a new lava dome was observed at the summit. Extrusion continued through the next year as the lava dome grew, sometimes sprouting a tall lava spine from its perimeter. Meanwhile, more ash, rockfall and lahars came down the volcano’s slopes. On 25 June, 1997 a large eruption event produced a northbound pyroclastic that killed 19 people and destroyed the island’s only airport. In October of ’97, a major collapse of the dome occurred, producing more pyroclastic flows to the northeast. This period of dome growth and collapse would continue throughout the eruptive phase which ended in 2003.
Before the eruption, Montserrat had been a green island and actually bore the nickname “Emerald Isle of the Carribean” because its coast resembled that of Ireland. It had become a popular tourist destination, and for about fifteen years preceding the unfortunate arrival of Hurricane Hugo, it was the tropical home of AIR (Associated Independent Recording) studio. This brought many famous popular recording artists to the island, including Pink Floyd, The Police, Duran Duran and also Jimmy Buffet, whose hit song Volcano is all about the then-dormant volcano of Montserrat.
After the volcano blew, many Montserratians left the island and moved to Great Britain, who made a special concession to allow the people of their overseas territory to gain full British citizenship. Other islanders stayed, but were relocated to the north of the island outside the large exclusion zone.
In the last twelve years, the volcano has had two more eruptive phases, one short one for two months in 2004, and the next one beginning in 2005 and lasting eight years. Intense monitoring and the exclusion zone remain in effect. The volcano is now tended by the Montserrat Volcano Observatory operated by the British Geological Survey.
Five points go to Jesper and three to Leslie for this week’s hunt. Thank you for playing. Check back here Tuesday 03:00 UTC (Iceland-time) for a new adventure at a new volcano.