West Indies - Volcano risk
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Actual volcanic disasters in the Eastern Caribbean over the past 300 years
RECENT ACTIVE VOLCANOES
Sixteen Holocene volcanoes are located in the Lesser Antilles, from the southernmost island of
Grenada to the northern island of Saba, of the Dutch Antilles. Of these, nearly 90% are andesitic
Activity here is dominantly explosive with most eruptions recorded with explosive elements.
Whereas the most common eruption size in most regions is VEI 2, here nearly half of all eruptions
with a given size have been VEI 4. Nearly 70% of the volcanoes have Holocene records of producing
pyroclastic flows, and about three quarters of all recorded eruptions here produced pyroclastic
flows. Pyroclastic flows are recorded in about half of all historical eruptions, whilst only 2% of historical events have recorded lava flows. About a third of historical eruptions have resulted in lahars. Four historical eruptions have generated tsunamis.
Soufriere de St Vincent
The Soufriere volcano is a 1220 m high stratovolcano which occupies the northern part of the island of St. Vincent. It is one of the most active centres of volcanism in the Caribbean and has a record of activity dating back to the Pleistocene. This stratovolcano has developed as a result of the subduction of the Atlantic Ocean crust beneath the Caribbean Plate. Twenty-one Holocene eruptions are confirmed at Soufrière St. Vincent, between 2380 BC and 1979 AD. These eruptions have varied in size from VEI 0 to 4, however all eruptions prior to the 1700s are of unknown magnitude. These eruptions however, all have records of producing explosive products including pyroclastic flows. Petrochemical work has shown that magmas involved in the explosive eruptions were quite narrow in compositional range, mainly comprising basaltic andesites. The 1902–03 eruption involved a late stage basaltic component in March 1903. However, activity in the last 1000 years generated notably more homogeneous magmas with a narrower range than the older eruptive periods previously reported in the literature, suggesting a significant variation in the magmatic reservoir feeding system with time.
Montagne Pelée ( Martinique)
Montagne Pelée (1394 m), forming the northern end of the island of Martinique, is the most active volcano of the Lesser Antilles arc. Historical eruptions date back to the 18th century; only two modest phreatic or phreatomagmatic eruptions took place prior to 1902. Five historical eruptions are recorded at Montagne Pelée.
Being small islands, relatively high proportions of the population live within 10 km of the volcanoes
here, with about 5% of the population of Martinique living
within this distance. The whole population lives within 100 km of these volcanic centres.
Boudon et al. (2005) present possible future eruption scenarios for Martinique and suggest that the
most probable activity is phreatic events, dome-forming eruptions or open-vent pumiceous
eruptions. They also suggest that collapse of the south-western flank of the volcano is of low
probability, but consider it due to the devastating effects it could have, including potential for
directed blasts and tsunami generation. They present a hazard map for Martinique based on a
quantitative assessment of volcanic hazard, showing hazard concentrated around Montagne Pelée
and St. Pierre, with much of the southern half of the island being of low hazard. Pelée is monitored by the Observatoire Volcanologique et
Eight eruptions occurred at the Soufriere during historic time. Latest phreatic activity occurred in 1975-76. As of the Martinique, relatively high proportions of the population live within 10km of the volcano. On the Guadeloupe island about 17% of the population living within this distance. Komorowski et al., (2005) suggest future eruption scenarios for Guadeloupe in order of decreasing
probability of occurrence of: intense prolonged fumarolic activity, phreatic eruptions, edifice
collapse eruptions, effusive and explosive dome-forming eruptions and large explosive eruptions.
They present an integrated hazard map for these scenarios with the area of highest hazard being
located around the summit of La Soufrière of Guadeloupe and to the south-west, with additional
high hazard in the valleys radiating from the volcano. The volcano is monitored by the Observatory volcanologique and sismologique de Guadeloupe (OVSG/IPGP)
Soufriere de Monserrat
The Soufriere Hills volcano is situated to the south of central Montserrat. Being a small island, all
infrastructure and population here lies within 20 km of the volcano. Indeed the 100 km radius of Soufriere Hills extends to encompass much of Guadeloupe, St. Kitts and Nevis and Antigua and
Barbuda, exposing much of the infrastructure here. Soufrière Hills volcano is currently active. Historic activity in the 17 th Century produced the Castle
Peak lava dome and seismic activity has occurred in swarms at 30 year intervals in the 20 th Century.
No other eruptions are recorded until the ongoing eruptions which started in August 1995. Eruptive
The 5 volcanoes in Dominica form a chain across the island. Two volcanoes have no confirmed Holocene activity on record. Morne Trois Pitons, Morne Plat Pays and Morne Watt have a Holocene eruption record, including historical activity at the latter. Unrest has been described at Morne aux Diables and Morne Trois Pitons since 1900 AD. Being only a small island, measuring no more than 50 km across the country in its entirety lies within a short distance from Holocene volcanoes. Indeed the 100 km radius of the Dominican volcanoes extends beyond Dominica to encompass Guadeloupe and much of Martinique, exposing much of the critical infrastructure on these islands. The whole population of the island resides within 30 km of one or more Holocene volcanoes. Indeed, about 84% of the population live within 10 km. The highest proximal population is at Morne Plat Pays, where several towns lie in the valleys radiating from the volcano and the capital, Roseau, lies within 10 km.
Carte des Risques - Montagne Pelée
Soufriere Hills eruption 1997 -(H.Gaudru)