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A volcanic eruption is the expulsion of magma and gas from the Earth's interior. Most current volcanic eruptions are the result of one of three eruption mechanisms.


Both the Smithsonian website and the website for VolcanoDiscovery post details on recent volcanic eruptions worldwide, while the U.S. Geologic Survey's Volcano Hazards website details eruptions within the United States. There are also several volcano observatories that ...


Volcanic eruptions occur when magma builds up beneath the Earth's crust and forces its way to the surface. Natural vents in the crust allow magma passage to the surface, and eruptions occur when the magma that forms is less dense than the material above it, causing it t...


The two basic types of volcanic eruptions are effusive and explosive eruptions. In effusive eruptions, magma flows to the surface and down the sides of the volcano as lava. In explosive eruptions, magma violently rips through the top portion of the volcano and reaches t...


According to the United States Geological Survey, before a volcanic eruption, magma must travel upwards through rock. The travelling magma produces these precursors to an eruption: an increase in earthquakes beneath a volcano, volcanic tremors, disturbance of ground fea...


Various factors trigger a volcanic eruption. The three predominant factors are the magma's buoyancy, the pressure from the gases that separate in the magma and the merger of a new batch of magma with a chamber already filled with magma.


The most violent type of volcanic eruption is a Plinian eruption. This type can produce plumes of ash that are more than 30 miles high.


Volcanic eruptions mainly produce steam (H2 0 ), sulfur dioxide (SO 2 ) and carbon dioxide (CO 2 ). They do release other gases in lesser amounts, such as carbon monoxide (CO), helium (He), hydrogen (H 2 ), hydrogen chloride (HCL), hydrogen fluoride (HF) and hydrogen su...


According to the Oregon State University Department of Geosciences, a volcanic eruption may become violent if pressure builds up inside the volcano for any reason. An explosive eruption is much more dangerous than a steady flow of magma and can spread ash and pyroclasti...


The nature of a volcanic eruption is determined by the temperature, viscosity and the amount of dissolved gases in the magma, according to San Diego State University. These factors determine whether an eruption is calm and nonviolent or explosive.