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A volcano tectonic earthquake or volcano earthquake is caused by the movement of magma beneath the surface of the Earth. [1] The movement results in pressure changes where the rock around the magma has a change in stress. At some point, this stress can cause the rock to break or move. This seismic activity is used by scientists to monitor ...
In explosive volcanic eruptions, the sudden release of gases from magma may cause rapid movements of the molten rock. When the magma encounters water, seawater, lake water or groundwater, it can be rapidly fragmented. The rapid expansion of gases is the driving mechanism of most explosive volcanic eruptions.
Vulcanian eruptions are a type of volcanic eruption named after the volcano Vulcano. [24] It was named so following Giuseppe Mercalli's observations of its 1888–1890 eruptions. [25] In Vulcanian eruptions, intermediate viscous magma within the volcano make it difficult for vesiculate gases to escape.
The resulting pressure eventually breaks through the surface, and the release of pressure causes more gas to exsolve, doing so explosively. The gas may expand at hundreds of metres per second, expanding upward and outward. As the eruption progresses, a chain reaction causes the magma to be ejected at higher and higher speeds. [3]
Before and during volcanic eruptions, volatiles such as CO 2 and H 2 O partially leave the melt through a process known as exsolution. Magma with low water content becomes increasingly viscous. If massive exsolution occurs when magma heads upwards during a volcanic eruption, the resulting eruption is usually explosive. [104]
The caldera is the enormous volcanic crater left from the last time Yellowstone experienced a giant eruption, 640,000 years ago. It covers an area about 30 by 45 miles .
Super volcano is the term used to describe volcanoes that have gradually over time built up immense amounts of magma and could wreak havoc if ejected onto the planet's surface. And in the heart of ...
In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens . Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent.