Volcanoes have existed since the bi

Volcanoes have existed since the birth of the earth, and they have helped shape the continents as we know them. The word volcano is thought to have come from Roman mythology, specifically derived from Vulcan, the Roman god of fire who was thought to be Jupiter’s blacksmith and responsible for making arrows and shields. Vulcan also had a Greek equivalent, known as Hephaestus, whose name means “burning” or “flaming.” Volcanoes were featured in ancient poetry, where they are described as the blacksmith’s workshop. When a mountain erupted, the ancients thought it was caused by smoke escaping through the chimney of Vulcan’s workshop when he was at work.

But what are volcanoes, really? A volcano is an opening in the Earth’s surface which allows hot magma, volcanic ash and gases to escape from the magma chamber below the surface. Volcanic eruptions can cause destruction and consequent disaster in several different ways. One is the volcanic eruption itself, causing harm from the explosion of the volcano or the immediate fall of rock. Then there is lava - molten rock or liquid rock - that may be produced during the eruption of a volcano. As it leaves the volcano, the hot lava destroys any buildings and plants in its path. Third, there is volcanic ash, consisting of fragments of pulverized rock, minerals and volcanic glass, which may form a cloud and settle thickly in nearby locations. When volcanic ash is mixed with water it forms a concrete-like material, and in sufficient quantity, ash may cause roofs to collapse under its weight. Small quantities of volcanic ash will also harm humans if inhaled.

However, the main danger to humans in the immediate surroundings of a volcanic eruption is pyroclastic flows. These are currents of hot gas and rock which can reach speeds of up to 700 kmh (450 mph) and temperatures of about 1,000 °C (1,830 °F). It is believed that the Roman town of Pompeii near Naples was destroyed by a pyroclastic flow in the eruption of Mount Vesuvius in AD 79, and that heat was the main cause of death of people and not, as previously believed, the inhalation of ash.

One recent volcanic eruption causing chaos and disaster was the Puyehue-Cordón Caulle eruption in Chile in 2011. At least 3,500 people were evacuated from nearby areas, while the ash cloud was blown across cities all around the Southern hemisphere, creating travel chaos when airlines were forced to cancel hundreds of flights. Ash poses a threat to aircrafts because once sucked into engines, it can be transformed into molten glass by the high engine temperatures and can cause an engine to fail. Further, ski resorts in Argentina had to be closed, a nearby river was contaminated and its temperature rose to 45 °C (113 °F) and pastureland in Southern Argentina was destroyed.

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Volcanoes have existed since the birth of the earth, and they have helped shape the continents as we know them. The word volcano is thought to have come from Roman mythology, specifically derived from Vulcan, the Roman god of fire who was thought to be Jupiter’s blacksmith and responsible for making arrows and shields. Vulcan also had a Greek equivalent, known as Hephaestus, whose name means “burning” or “flaming.” Volcanoes were featured in ancient poetry, where they are described as the blacksmith’s workshop. When a mountain erupted, the ancients thought it was caused by smoke escaping through the chimney of Vulcan’s workshop when he was at work.Mas o que são vulcões, realmente? Um vulcão é uma abertura na superfície da terra, que permite que o magma quente, cinzas vulcânicas e dos gases de escape da câmara de magma abaixo da superfície. Erupções vulcânicas podem causar destruição e consequente catástrofe de várias maneiras diferentes. Uma é a erupção vulcânica em si, causando danos da explosão do vulcão, ou a imediata queda de rocha. Então há lava - rocha fundida ou rocha líquida - que pode ser produzido durante a erupção de um vulcão. Assim que sai do vulcão, a lava quente destrói qualquer edifícios e plantas em seu caminho. Em terceiro lugar, há cinzas vulcânicas, constituído por fragmentos de rocha pulverizada, minerais e vidro vulcânico, que podem formar uma nuvem e resolver grossa em locais próximos. Quando cinzas vulcânicas é misturada com água dá forma a um material concreto, e em quantidade suficiente, ash pode causar telhados a desmoronar sob seu peso. Pequenas quantidades de cinzas vulcânicas também irão prejudicar os seres humanos se inalado.No entanto, o principal perigo para os seres humanos nas imediações de uma erupção vulcânica é um fluxo piroclástico. Estas são as correntes de gás quente e rock que pode atingir velocidades de até 700 kmh (450 mph) e temperaturas de cerca de 1.000 ° C (1.830 ° F). Acredita-se que a cidade romana de Pompéia, perto de Nápoles foi destruída por um fluxo piroclástico na erupção do Vesúvio em 79 D.C., e que o calor foi a principal causa de morte de pessoas e não, como anteriormente se acredita, a inalação de cinzas.Uma erupção vulcânica recente, causando o caos e o desastre foi a erupção do Puyehue-Cordón Caulle no Chile em 2011. Pelo menos 3.500 pessoas foram evacuadas de áreas próximas, enquanto a nuvem de cinzas foi soprada através de cidades ao redor do hemisfério sul, criando o caos de viagem quando as companhias aéreas foram obrigadas a cancelar centenas de vôos. Cinza representa uma ameaça para aeronaves, porque uma vez sugada por motores, pode ser transformado em vidro derretido pelas temperaturas elevadas do motor e pode causar um motor falhar. Além disso, estâncias de esqui na Argentina tiveram que ser fechados, um rio próximo estava contaminado e sua temperatura subiu para 45 ° C (113 ° F) e pastagens no sul da Argentina foi destruída.