The Instituto Nacional de Sismologia, Vulcanologia, Meteorologia, e Hidrologia in Guatemala has reported a new eruptive episode on Mount Fuego, a stratovolcano (cone shaped volcano made up of layers of ash and lava) that forms part of La Horqueta volcanic complex in the southern part of the country, the first such event in 2018. The eruption began on Wednesday 31 January, with a series of explosions that produced an ash column that rose 1.5 km above the summit of the volcano, and drifted 20 km to the southwest. This was accompanied by a series of lava fountains that rose 300-500 m above the summit, and which fed lave flows that descended 800 m down the west flank of the volcano and 600 m down the southeast and east flanks. On Thursday 1 February these eruptions continued, producing a series of ash columns that rose as high as 3.2 km above the volcano and drifted to the northeast, southwest and west, with ash falls recorded in communities up to 18 km from the volcano, prompting the evacuation of 2800 people from communities close to Fuego. This activity fell off sharply at about 4.30 pm local time, though the volcano continued to undergo smaller eruptions for the next five days, producing ash columns up to 750 m high and showers of incandescent material that rose up to 200 m above the summit.
Eruption on Mount Fuego, Guatemala, on 1 February 2018. Jiuwit Rosas.
Fuego has been more-or-less constantly active at some level since records in the area began (circa 1524). It forms part of La Horqueta volcanic complex, which also includes the Acatenango volcano to the north, a complex volcano with at least five separate vents, the complex siting on the site of the ancient Meseta volcano, which is thought to have collapsed following a major volcanic episode about 8500 years ago, causing a debris flow that reached the sea, 50 km away.
The approximate location of Mount Fuego. Google Maps.
The volcanoes of Guatemala, and Central America in general, are fed by the subduction of the Cocos Plate beneath the Caribbean Plate along the Middle American Trench, which runs roughly parallel to the southwest coast of the isthmus. As the Cocos Plate sinks into the Earth, it passes under Central America, which lies on the western margin of the Caribbean Plate. As this happens it is heated by the friction and the heat of the planet's interior, causing the sinking plate to partially melt. Some of the melted material then rises through the overlying Caribbean Plate as magma, fuelling the volcanoes of Central America.
Diagrammatic representation of the subduction of the Cocos Plate beneath the Caribbean Plate along the Middle American Trench. VCS Mining.
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