what are the three stages of volcanic activity?
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Scientists have categorized volcanoes into three main categories: active, dormant, and extinct. An active volcano is one which has recently erupted and there is a possibility that it may erupt soon. A dormant volcano is one which has not erupted in a long time but there is a possibility it can erupt in the future.
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A cross section of a composite volcano reveals alternating layers of rock and ash: (1) magma chamber, (2) bedrock, (3) pipe, (4) ash layers, (5) lava layers, (6) lava flow, (7) vent, (8) lava, (9) ash cloud.
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['Tephra. Tephra is a term used to describe igneous rocks that formed during a volcanic eruption that blew molten rock into the air. ... ', 'Lava rocks. ... ', 'Volcanic ash is a type of tephra. ... ', 'Lapilli. ... ', 'Lava bombs. ... ', 'Violent volcanic eruptions.']
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['Geophysical (e.g. Earthquakes, Landslides, Tsunamis and Volcanic Activity)', 'Hydrological (e.g. Avalanches and Floods)', 'Climatological (e.g. Extreme Temperatures, Drought and Wildfires)', 'Meteorological (e.g. Cyclones and Storms/Wave Surges)', 'Biological (e.g. Disease Epidemics and Insect/Animal Plagues)']
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['Pyroclastic Density Currents (pyroclastic flows and surges)', 'Lahars.', 'Structural Collapse: Debris flow-Avalanches.', 'Dome Collapse and the formation of pyroclastic flows and surges.', 'Lava flows.', 'Tephra fall and ballistic projectiles.', 'Volcanic gas.', 'Tsunamis.']
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['Lava. Lava (molten rock) can erupt as fire fountains or lava flows (when it is runny) or as steep-sided domes (when it is viscous). ... ', 'Pyroclastic flows. ... ', 'Phreatic explosions. ... ', 'Lahars. ... ', 'Jökulhlaups. ... ', 'Landslides. ... ', 'Volcanic earthquakes. ... ', 'Tsunamis.']
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Image courtesy of USGS. There are two predominant types of volcanic eruptions: Effusive eruptions – magma rises through the surface and flows out of the volcano as a viscous liquid called lava. Explosive eruptions – magma is torn apart as it rises and reaches the surface in pieces known as pyroclasts.
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['(i) Undersed earthquakes:', '(ii) Landslides:', '(iii) Volcanic Eruptions:', '(iv) Meteorites and Asteroids:']
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Principal Types of Volcanoes. Geologists generally group volcanoes into four main kinds--cinder cones, composite volcanoes, shield volcanoes, and lava domes.
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Volcanic eruptions pull materials up from deep within the earth to form various volcanic landforms, such as lava domes, lava plateaus, fissure eruptions, craters and calderas. Learn about these volcanic landforms and how they are created.
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Volcanoes are most common in these geologically active boundaries. The two types of plate boundaries that are most likely to produce volcanic activity are divergent plate boundaries and convergent plate boundaries. At a divergent boundary, tectonic plates move apart from one another.
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There are three kinds of rock: igneous, sedimentary, and metamorphic.
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The three main parts of a volcano are the chamber, the vent, and the crater. The chamber is where the magma is stored. Magma is the molten rock that...
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The primary factors that determine the nature of volcanic eruptions include the magma's temperature, its composition, and the amount of dissolved gases it contains.
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['Before an Eruption. Before a volcano erupts, there is normally an increase in earthquakes and tremors near and under the volcano. ... ', 'Volcanic Gas. During an eruption of a volcano, gases dissolved in the magma are released into the air. ... ', 'Lava. ... ', 'Volcanic Landslide. ... ', 'Pyroclastic Flows. ... ', 'Volcanic Ash.']
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Volcanic ash is formed during explosive volcanic eruptions. Explosive eruptions occur when gases dissolved in molten rock (magma) expand and escape violently into the air, and also when water is heated by magma and abruptly flashes into steam. The force of the escaping gas violently shatters solid rocks.
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Volcanic eruptions pull materials up from deep within the earth to form various volcanic landforms, such as lava domes, lava plateaus, fissure eruptions, craters and calderas.