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A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. [1] Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit ...
Types of volcanic eruptions. Some of the eruptive structures formed during volcanic activity (counterclockwise): a Plinian eruption column, Hawaiian pahoehoe flows, and a lava arc from a Strombolian eruption. Several types of volcanic eruptions —during which material is expelled from a volcanic vent or fissure —have been distinguished by ...
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth ...
Mount Semeru and Mount Bromo in East Java. Together, they form the Bromo Tengger Semeru National Park. Mount Agung and Mount Batur in Bali. Galunggung in West Java. Krakatoa. A violent eruption in August 1883 resulted in the obliteration of the three-peaked volcanic island. Anak Krakatoa.
The Cascade Arc includes nearly 20 major volcanoes, among a total of over 4,000 separate volcanic vents including numerous stratovolcanoes, shield volcanoes, lava domes, and cinder cones, along with a few isolated examples of rarer volcanic forms such as tuyas. Volcanism in the arc began about 37 million years ago; however, most of the present ...
Dacite (/ ˈdeɪsaɪt /) is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz.
Effusive eruptions are most common in basaltic magmas, but they also occur in intermediate and felsic magmas. These eruptions form lava flows and lava domes, each of which vary in shape, length, and width. [2] Deep in the crust, gasses are dissolved into the magma because of high pressures, but upon ascent and eruption, pressure drops rapidly ...
In volcanology, a Strombolian eruption is a type of volcanic eruption with relatively mild blasts, typically having a Volcanic Explosivity Index of 1 or 2. [1] Strombolian eruptions consist of ejection of incandescent cinders, lapilli, and volcanic bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in ...