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Montserrat is a British Overseas Territory in the Caribbean. The island is in the Leeward Islands, which is part of the chain known as the Lesser Antilles, in the West Indies. Montserrat measures approximately 16 km (10 mi) in length and 11 km (7 mi) in width, with approximately 40 km (25 mi) of coastline. Montserrat is nicknamed "The Emerald Isle of the Caribbean" both for its resemblance to coastal Ireland and for the Irish ancestry of many of its inhabitants. Montserrat is the only non-fully sovereign full member of the Caribbean Community and the Organisation of Eastern Caribbean States.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica, with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as 15 km (9.3 mi).
A pyroclastic flow is a fast-moving current of hot gas and volcanic matter that flows along the ground away from a volcano at average speeds of 100 km/h (62 mph) but is capable of reaching speeds up to 700 km/h (430 mph). The gases and tephra can reach temperatures of about 1,000 °C (1,830 °F).
Mount Pelée or Mont Pelée is an active volcano at the northern end of Martinique, an island and French overseas department in the Lesser Antilles Volcanic Arc of the Caribbean. Its volcanic cone is composed of stratified layers of hardened ash and solidified lava. Its most recent eruption was in 1932.
Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption. Types of volcanic cones include stratocones, spatter cones, tuff cones, and cinder cones.
Plymouth is a ghost town and the de jure capital of the island of Montserrat, an overseas territory of the United Kingdom located in the Leeward Island chain of the Lesser Antilles, West Indies.
A pyroclastic surge is a fluidized mass of turbulent gas and rock fragments that is ejected during some volcanic eruptions. It is similar to a pyroclastic flow but it has a lower density or contains a much higher ratio of gas to rock, which makes it more turbulent and allows it to rise over ridges and hills rather than always travel downhill as pyroclastic flows do.
The Soufrière Hills are an active, complex stratovolcano with many lava domes forming its summit on the Caribbean island of Montserrat. After a long period of dormancy, the Soufrière Hills volcano became active in 1995 and has continued to erupt ever since. Its eruptions have rendered more than half of Montserrat uninhabitable, destroying the capital city, Plymouth, and causing widespread evacuations: about two-thirds of the population have left the island. Chances Peak in the Soufrière Hills was the highest summit on Montserrat until the mid-1990s, but it has since been eclipsed by various rising and falling volcanic domes during the recent volcanic activity.
In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on Earth are lava dome forming. The geochemistry of lava domes can vary from basalt to rhyolite although the majority are of intermediate composition The characteristic dome shape is attributed to high viscosity that prevents the lava from flowing very far. This high viscosity can be obtained in two ways: by high levels of silica in the magma, or by degassing of fluid magma. Since viscous basaltic and andesitic domes weather fast and easily break apart by further input of fluid lava, most of the preserved domes have high silica content and consist of rhyolite or dacite.
La Soufrière or Soufrière Saint Vincent is an active stratovolcano on the Caribbean island of Saint Vincent in Saint Vincent and the Grenadines. It is the highest peak in Saint Vincent, and has had five recorded explosive eruptions since 1718. The latest eruptive activity began in December 2020, with a series of explosive events beginning in April 2021.
A Vulcanian eruption is a type of volcanic eruption characterized by a dense cloud of ash-laden gas exploding from the crater and rising high above the peak. They usually commence with phreatomagmatic eruptions which can be extremely noisy due to the rising magma heating water in the ground. This is usually followed by the explosive clearing of the vent and the eruption column is dirty grey to black as old weathered rocks are blasted out of the vent. As the vent clears, further ash clouds become grey-white and creamy in colour, with convolutions of the ash similar to those of Plinian eruptions.
Peléan eruptions are a type of volcanic eruption. They can occur when viscous magma, typically of rhyolitic or andesitic type, is involved, and share some similarities with Vulcanian eruptions. The most important characteristic of a Peléan eruption is the presence of a glowing avalanche of hot volcanic ash, called a pyroclastic flow. Formation of lava domes is another characteristic. Short flows of ash or creation of pumice cones may be observed as well.
Radio Antilles was a radio station operated by the Antilles Radio Corporation which began broadcasting in 1963. It was located on the Caribbean island of Montserrat.
A lava spine is a vertical growth of solid lava that is forced from a volcanic vent. A lava spine can either be formed by viscous lava slowly being pushed out of the vent, or by magma that has solidified within the vent before being pushed out.
Chances Peak is a summit of the active complex stratovolcano named Soufrière Hills, the primary volcanic complex of Montserrat, a British overseas territory located in the Caribbean Sea. It was the highest point on the island until the mid-1990s, when fluctuating volcanic domes during the 1995–1999 Soufrière Hills eruptions eclipsed the peak in height.
The Bridge River Vent is a volcanic crater in the Pacific Ranges of the Coast Mountains in southwestern British Columbia, Canada. It is located 51 km (32 mi) west of Bralorne on the northeastern flank of the Mount Meager massif. With an elevation of 1,524 m (5,000 ft), it lies on the steep northern face of Plinth Peak, a 2,677 m (8,783 ft) high volcanic peak comprising the northern portion of Meager. The vent rises above the western shoulder of the Pemberton Valley and represents the northernmost volcanic feature of the Mount Meager massif.
Barry Voight is an American geologist, volcanologist, author, and engineer. After earning his Ph.D. at Columbia University, Voight worked as a professor of geology at several universities, including Pennsylvania State University, where he taught from 1964 until his retirement in 2005. He remains an emeritus professor there and still conducts research, focusing on rock mechanics, plate tectonics, disaster prevention, and geotechnical engineering.
A block and ash flow or block-and-ash flow is a flowing mixture of volcanic ash and large angular blocks commonly formed as a result of a gravitational collapse of a lava dome or lava flow. Block and ash flows are a type of pyroclastic flow and as such they form during volcanic eruptions. In contrast to other types of pyroclastic flows, block and ash flows do not contain pumice and the volume of block and ash flow deposits is usually small. Block and ash flow deposits have densities in the range of 1600 to 2000 kg/m3, two to five times greater than ash fall deposits. Some blocks in block and ash flow deposits may have thin and shiny coatings of carbon derived from charcoal formed from vegetation trapped by the flow.
La Soufrière, a stratovolcano on the Caribbean island of Saint Vincent in Saint Vincent and the Grenadines, began an effusive eruption on 27 December 2020. On 9 April 2021 there was an explosive eruption, and the volcano "continued to erupt explosively" over the following days, with pyroclastic flows. The activity pattern of the ongoing eruption is comparable to that of the event that occurred in 1902, which had a Volcanic Explosivity Index (VEI) of 4. The volcano is known to have erupted 23 times in the last 4,000 years, and had been dormant since 1979.
References
- ↑ "The volcanic geology and petrology of Montserrat, West Indies | Journal of the Geological Society". jgs.lyellcollection.org. Retrieved 2018-11-09.