Volcanic and Associated Hazards in the Lesser Antilles
- Category I:
Events that occur every few decades and affect only the parent volcano’s immediate flanks.
- Category II:
Events that occur every few hundreds to thousands of years with effects extending beyond the flanks of the parent volcano, often over large parts of the island.
- Category III:
Events which occur every few tens to hundreds of thousands of years, and affect several islands; these may include non-volcanic activity such as sector collapse of the volcano’s flanks with associated earthquakes and tsunamis.
Category II hazards are typified by large Plinian-type eruptions which have generated widespread air falls, valley-fill pumice and ash flows (high aspect ratio ignimbrites, HARIs) and extensive ash hurricanes (low aspect ratio ignimbrites, LARIs). Examples of such activity were the eruption of Mt. Pelée around 2000 years ago, and the eruption that produced the Roseau tuff on Dominica approximately 30,000 years ago. Although this type of activity has not been witnessed by Europeans, several such eruptions occurred during the 3000-year occupation of the islands by pre-Columbian peoples. Category II hazard is also exemplified by the older geology of the Quill, St. Eustatius (Statia), where, some 30,000 years ago extrusion of rhyolitic magma onto a shallow marine shelf (about 3 km offshore from an older island) generated pyroclastic activity which became partially phreatomagmatic with increased energy release. The adjacent island was engulfed by surge deposits that eventually linked the early Quill to the older island.
Category III hazards involve major events during which, in addition to large new geological structures appearing on one island, associated seismic effects and tsunamis are likely to be experienced on adjacent islands. Examples of this type are illustrated by the geology of St. Lucia, Dominica and St. Vincent, where large arcuate depressions occur on the back-arc coasts. These structures have been interpreted as either calderas or as resulting from the gravity collapse of the steeper back-arc flanks of the islands. Whatever their origin, up to 12 km3 of land may be consumed.
At present the reactions of the governments of the many small islands to volcanic hazards vary considerably. Most are struggling with variable success (according to their level of affluence/impoverishment) to consider and plan for the short-term or category I hazard. For Saba and St. Eustatius where, and possibly because, we have prepared detailed category I and II hazard assessment reports, these reports are “lost” in the offices of the Netherlands Antilles government in Curaçao “awaiting approval” for publication and for 6 years have been unavailable to the administration and populations of these volcanic islands.
The mitigation of volcanic disasters requires not only hazard assessment reports but a wholehearted effort by the local government including education of the population at risk. Interaction between the international scientific community and local governments in developing countries is complicated by political-social-economic factors. The whole complex provides a new subject of geohazard management, without which the hazard assessment reports are unlikely to mitigate natural disaster.
KeywordsDepression Silicate Geochemistry Explosive Drilling
Unable to display preview. Download preview PDF.
- Anonymous (1986) Scientists call for volcano monitoring. Geotimes 32: 8–9Google Scholar
- Case J, Dengo G (eds) (in press) The geology of North America Vol. H: The Caribbean region. Geol Soc AmGoogle Scholar
- Cotner J (1975) A motoring guide to St. Kitts. Heidelberg Press USA, 42 ppGoogle Scholar
- Fiske RS (1981) Scientists and the news media: contrasting interaction during the two volcanic crises in the eastern Caribbean. Abstr IAVCEI Symp “Arc Volcanism ” Tokyo, 93 ppGoogle Scholar
- Goodwin RC (1978) The Lesser Antilles Archaic: new data from St. Kitts. J Virgin Islands Archaeolog Soc 5: 6–16Google Scholar
- Hartog J (1975) History of Saba. Van Guilder NV, Saba, 140 ppGoogle Scholar
- Heilprin A (1903) Mont Pelée and the tragedy of Martinique. Lippincott, Philadelphia London, 337 ppGoogle Scholar
- LaCroix A (1904) La Montagne Pelée et ses eruptions. Masson, Paris, 622 ppGoogle Scholar
- Robson GR, Tomblin JF (1966) Catalogue of active volcanoes of the world including solfatara fields. Part XX West Indies. Int Assoc Volcanol Naples, 56 ppGoogle Scholar
- Roobol MJ, Smith AL (1979) Archaeological implications of some radiocarbon dating on Saba and St. Kitts. Proc 8th Int Congress pre-Columbian cultures of the Lesser Antilles, pp 168–176Google Scholar
- Roobol MJ, Smith AL, Tomblin JF (unpubl a) An assessment of the volcanic hazard on the islands of Saba and St. Eustatius in the northern Lesser Antilles. Confidential Report Rijks Geologische Dienst, 205 ppGoogle Scholar
- Roobol MJ, Smith AL, Tomblin JF (unpubl b) Volcanology of the islands of Saba and St. Eustatius in the northern Lesser Antilles. Part I - Geology, pyroclastic stratigraphy and petrology. Confidential Report Rijks Geologische Dienst, 165 ppGoogle Scholar
- Roobol MJ, Smith AL, Tomblin JF (unpubl c) Volcanology of the islands of Saba and St. Eustatius in the northern Lesser Antilles. Part II - Volcanic hazard. Confidential Report Rijks Geologische Dienst, 62 ppGoogle Scholar
- Roobol MJ, Petitjean Roget H, Smith AL (1976) Mt. Pelée and the island population of Martinique. Proc VI Int Congress pre- Columbian cultures of the Lesser Antilles, pp 46–53Google Scholar
- Rowley KC (1978) Stratigraphy and geochemistry of the Soufrière volcano, St. Vincent, West Indies. Unpubl Ph.D thesis, Univ West Indies, St. Augustine, Trinidad, 282 ppGoogle Scholar
- Semet MP, Boudon G, Vincent PM (1986) Volcanological evolution of La Grande Découverte (La Soufrière), Guadeloupe, FWI Abstr Int Volcanological Congress, New Zealand, 73 ppGoogle Scholar
- Simkin T, Siebert L, McClelland L, Bridge D, Newhall C, Latter JH (1981) Volcanoes of the world. Smithsonian Institution, Hutchinson Ross, Stroudsburg; 232 ppGoogle Scholar
- Smith AL, Roobol MJ (1980) Late pre-historic and historic activity of Mt. Pelée, Martinique. Abstracts IX Carib Geol Conf, pp 68–69Google Scholar
- Smith AL, Roobol MJ (in prep.) Mt. Pelée, Martinique - a study of an active island arc volcano. Mem. Geol. Soc. America.Google Scholar
- Smith AL, Roobol MJ, Rowley K (1979) Pyroclastic character of the active volcanoes of the northern Lesser Antilles. Trans 4th Latin Am Geol Cong, pp 24–30Google Scholar
- Tomblin JF (1964) The volcanic history and petrology of the Soufrière region, St. Lucia. Unpubl Ph.D thesis, Oxford Univ, 213 ppGoogle Scholar
- UNDRO (1985) Volcanic emergency management. United Nations New York, 86 ppGoogle Scholar
- Wadge G (1985) Avoiding another St. Pierre. Volcano News 22: 4Google Scholar
- Westercamp D (1981) Assessment of volcanic hazards at Soufrière de Guadeloupe, FWI. Bull BRGM Sec IV (2): 187–197Google Scholar
- Westercamp D, Traineau H (1983b) Carte Géologigue de la Montagne Pelée à 1/20,000: Service Geol. Natl BRGM, OrleansGoogle Scholar
- Westermann JH, Keil H (1961) The geology of Saba and St. Eustatius. Uitg Natuurwet Studietering Suriname Ned Antillen 24: 1–175Google Scholar