The Volcano on the Island Ark Got Changed Again
The islands of the Eastern Caribbean or Lesser Antilles, form a curved chain of volcanic islands along the eastern margin of the Caribbean Sea that stretches ~850 km from Grenada in the south to Sombrero (north of Anguilla) in the northward. Such a curved chain of volcanic islands, which has formed every bit a result of magmatism associated with subduction, is referred to as an 'island arc'. Not all the islands of the Lesser Antilles, however, accept 'live' (likely to erupt again) volcanoes. Due north of Dominica the island arc splits into 2, and only the western arc of islands, known equally the 'Volcanic Caribbees' is agile. The eastern arc is referred to as the 'Limestone Caribbees'. Volcanism in the Limestone Caribbees died out many millions of years ago as the axis of volcanism migrated westwards due to changes in subduction geometry, and the old volcanic mural has since been eroded and covered by coral and limestone.
Volcanoes in the Eastern Caribbean
The Bottom Antilles includes 21 known, 'alive' (probable to erupt again) volcanoes spread beyond xi volcanically active islands, and volcanic eruptions are ane of the master hazards that threaten the Eastern Caribbean region. During the past 200 years over 30,000 people have been killed past volcanic activeness in this region and currently almost one million people are threatened by the straight effects of volcanic eruptions and about 2 and a one-half 1000000 more by related phenomena such as volcanic ash fall. Near of the islands of the Lesser Antilles have a single alive volcano that may erupt in the future (e.g. Nevis, Montserrat). The other islands are more complex, of which Commonwealth of dominica is the well-nigh extreme with no less than nine live volcanoes.
How are earthquakes and volcanoes formed in the Eastern Caribbean area
Historical volcanic activity in the Bottom Antilles
Historical eruptions in the Caribbean are by and large regarded as those that take occurred since Europeans settled the region and began producing written accounts of events. This period varies across the region; in most islands European settlement began in the early on 1600's, but was intermittent for most of the 17th Century, changing hands several times betwixt various European powers. Several early records of life in the islands include unsubstantiated reports of volcanic activity (east.g. in St. Kitts and St. Vincent). Conversely, radiocarbon dates of several eruptions (e.g. in Montserrat and Saba) imply that volcanoes in these islands were active during the historical period for the region, yet no written accounts have been found. There is, therefore, uncertainty both in defining the 'historical period' in the region and also with quantifying the actual number of historical eruptions. Best estimates, however, indicate that there take been at least 34 historical eruptions of volcanoes in the Lesser Antilles, 21 of these accept occurred since 1900; nine on land from volcanoes in Guadeloupe, Martinique, St. Vincent, Montserrat and Dominica, and fourteen from the submarine volcano Kick-'em-Jenny, ~9 km n of Grenada.
The 21 most recent eruptions accept shown a wide variety in both eruptive style and impact on the local population. Several accept been phreatic (steam) in nature, 1 a very small-scale phreatic eruption in Dominica in 1997 that went largely unnoticed and two much more serious phreatic eruptions in Guadeloupe in 1956 and 1976-1977, the latter resulted in a 3.v month evacuation of over 70,000 people.
Crest of the Half Style Ridge, 450 metres higher up sea level on 31st May 1902 showing the destructive bear on of heavy ashfall on vegetation following eruption of La Soufrière, St.Vincent in 1902. (Photo: T. Anderson, York Museum Collection)
The 1902 eruption of La Soufrière in St. Vincent was an explosive magmatic eruption that resulted in the deaths of at least ane,500 people; in dissimilarity, the 1971-1972 eruption at this volcano was wholly effusive, and resulted in the formation of a lava dome confined within the elevation crater. The 1979 eruption of La Soufrière was explosive followed past dome growth, and although there was some property damage no lives were lost. The 1902-1907 eruption of Montagne Pelée in Martinique is ranked among the earth's most devastating in terms of destruction of lives and property. This eruption was characterised by both effusive dome germination and explosive dome plummet, and led to the total destruction of the town of St. Pierre and the deaths of approximately thirty,000 people. A like eruption occurred from Montagne Pelée several years later, betwixt 1929 and 1932, this fourth dimension with no reported casualties.
The 15 submarine eruptions of Kick-'em-Jenny have been dominantly explosive, although in at least one case a lava dome was extruded. The Soufrière Hills Volcano in Montserrat has been in active eruption since 1995, and has had a major bear upon on the isle'due south population. The eruption is characterised past periods of dome-growth interspersed with dome collapse and minor explosions. The Soufrière Hills Volcano is the only volcano currently erupting in the Eastern Caribbean. In add-on to these volcanic eruptions, historical volcanic earthquake swarms have been observed in almost all of the Eastern Caribbean islands with live volcanic centres.
Pyroclastic flow at Soufrière Hills Volcano in Montserrat
While hurricanes are much more common in the Eastern Caribbean no hurricane has ever completely destroyed the capital of an Eastern Caribbean island (that is to say, made it completely uninhabitable) while volcanic eruptions have done so twice:
- to St. Pierre, Martinique in 1902 and
- to Plymouth, Montserrat in 1997
Additionally, while property destruction levels from astringent hurricanes mostly range from 10-25%, property destruction levels (and by extension, casualties) in the Eastern Caribbean caused by volcanic eruptions approach 100% in the near severely affected areas. Thus, the simply appropriate action that tin can be taken to prevent this is a total evacuation of the areas likely to be affected. For this reason, public teaching and awareness in advance is crucial to successful disaster preparedness and mitigation programmes in that it equips the public with the necessary data to exist able to make informed decisions and to facilitate (rather than obstruct) disaster response action in the event of a crunch.
In assessing the threat posed by volcanoes to Eastern Caribbean countries, it is useful to review data on actual volcanic disasters over the past 300 years (come across tables below). Keep in mind that at that place have been at least 15 other eruptions that have not resulted in large numbers of deaths or destroyed enough belongings to be ranked as disasters.
| Type of Event | No. of deaths caused |
|---|---|
| Volcanoes | > 30,000 |
| Earthquakes | Approx. 15,000 |
| Hurricanes | Approx. fifteen,000 |
| Tsunamis | Approx. l |
Bodily volcanic disasters in the Eastern Caribbean over the past 300 years
| Year | Volcano | Nature of Disaster (costs in twelvemonth 2000 dollars) * |
|---|---|---|
| 1718 | La Soufrière (St. Vincent) | Major explosive eruption. Unknown number of casualties amongst ethnic Caribs. |
| 1812 | La Soufrière (St. Vincent) | Major explosive eruption. About eighty deaths. Considerable damage to the carbohydrate manufacture. Economic toll unknown. |
| 1902 | La Soufrière (St. Vincent) | Major explosive eruption. About 1,600 deaths. Considerable harm to the saccharide industry. Economical cost estimated at US$200,000,000. |
| 1902 | Mt Pelé (Martinique) | Major explosive/effusive eruption. Over 30,000 deaths. Complete devastation of the city of St. Pierre. Other damage to agronomics considerable. Economic cost about U.s.a.$1,000,000,000. |
| 1976 – 77 | Soufrière (Guadeloupe) | Minor phreatic (steam) eruption. No casualties but economic cost estimated at US$1,000,000,000 |
| 1979 | La Soufrière (St. Vincent) | Moderate explosive eruption. No casualties but economic losses to the guild of US$100,000,000 |
| 1995 – present | Soufrière Hills (Montserrat) | Moderate explosive/effusive eruption. About xx deaths. Complete destruction of capital, Plymouth. Economical price not however estimated but in excess of U.s.$500,000,000. Complete devastation of the economy. |
| 2021 | La Soufrière (St. Vincent) | Major explosive/effusive eruption. Impairment to areas in the n of the isle. No deaths. ~18,000 persons evacuated |
Volcanic eruptions and earthquakes share the common feature that they happen adequately infrequently but when they exercise happen the consequences can be devastating. By unfortunate coincidence the mean interval betwixt such disasters is roughly comparable with ane homo lifetime so that the retention of the previous event would accept just most faded from public consciousness when the next one occurs. Maintaining public preparedness for geologic disasters through the long, quiescent periods, therefore, presents a significant challenge.
Related Resources
Volcanic Hazard Atlas of the Bottom Antilles
Source: https://uwiseismic.com/volcanoes/caribbean-volcanoes/
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