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The West Indies Region
Of the broad region known as the West Indies, only the Lesser Antilles, an arc of small islands formed by subduction of oceanic crust moving westward from the Mid-Atlantic Ridge, are volcanically active, forming the smallest of the CAVW regions. The small size of the islands places its towns and cities in close proximity to volcanoes, however, and the West Indies exceeds four other regions in population residing within 100 km of a volcano
The northern islands were discovered by Columbus on his second voyage, in 1493, and other islands on his third in 1498, but they were passed over by settlers preferring the Greater Antilles to the west. It was not until the 1630s and the sugar trade that Europeans started to settle in the islands. On Saba they chose grassy flatlands that were apparently the newly vegetated tops of very recent valley-filling pyroclastic-flow deposits. And on Martinique settlers noticed that Mont Pelée was suspiciously bare of vegetation. The first historical eruption, though, was on Guadeloupe around 1690. Ownership of islands shifted among the French, British, and Dutch, with Carib Indians showing fierce resistance to colonization on some islands. Several islands retain formal ties to Europe, whereas others have achieved independence in recent decades. Monitoring of the volcanoes is by the Seismic Research Unit of the University of the West Indies, principally by seismic data telemetered to their base in Trinidad, and by French observatories in Guadeloupe and Martinique. For many years the Montserrat Volcano Observatory was operated by the British Geological Survey, but since April 2008, the Observatory has been managed through a partnership of the Eastern Caribbean's two major geo-hazard organizations, the UWI Seismic Research Centre (Trinidad and Tobago) and the Institut de Physique du Globe de Paris (France).
This region has the lowest number of volcanoes (18), and smallest area of affected nations. Stratovolcanoes dominate (67%) in the West Indies to a degree matched only by Alaska. More than 90% of its eruptions are explosive, and the West Indies has the highest proportion (87%) of any region with eruptions that are strictly explosive, with no accompanying lava flows or domes. No other region has had a lower proportion of its eruptions that produce lava flows (6 of 132, or 4.5%). However, a high proportion of its eruptions compared to other regions have produced lava domes (12%, second to Region 12's 20%). Dome growth is often accompanied by pyroclastic flows, and three West Indian volcanoes are in the top ten globally in percentage of eruptions (for volcanoes with at least 5 eruptions) producing pyroclastic flows. More than 90% of the 54 dated eruptions of Mont Pelée, including the devastating 1902 eruption, have produced these hazardous flows.
Many detailed tephra studies, largely by British and French volcanologists, have produced a regional high of 68% radiocarbon eruption dates. Only 28 historical dates have been recorded in the West Indies and, like the Western United States, a high percentage of its eruptions are dated by non-historical techniques. Two major eruptions in 1902 drew world-wide attention to volcanoes in this region. The eruption of Montagne Pelée destroyed the city of St. Pierre, causing 29,000 fatalities, but the comparably large eruption of Soufrière St. Vincent had lesser impact in a more sparsely populated island. Recent bathymetric studies have documented the widespread occurrence of massive submarine debris-avalanche deposits resulting from collapse of island volcanoes. This region has been relatively quiet in recent decades following the 1979 eruption of Soufrière St. Vincent volcano. The only eruption since then (aside from a small phreatic eruption at the Valley of Desolation on Dominica in 1997 and a submarine eruption from Kick-em-Jenney volcano north of Grenada in 2001) has been the long-term eruption at Soufrière Hills volcano on Montserrat. This eruption began with phreatic explosions in 1995, and soon intensified. Pyroclastic flows and mudflows accompanying growth and destruction of a new summit lava dome eventually entirely overran the capital city of Plymouth. The eruption continues at this writing, with long-term economic disruption resulting from evacuation of much of the southern half of the island.
List of Holocene volcanoes in the West Indies region.