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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 ...
Magma that cools slowly within a magma chamber usually ends up forming bodies of plutonic rocks such as gabbro, diorite and granite, depending upon the composition of the magma. Alternatively, if the magma is erupted it forms volcanic rocks such as basalt , andesite and rhyolite (the extrusive equivalents of gabbro, diorite and granite ...
454 million-year-old volcanic ash between layers of limestone in the catacombs of Peter the Great's Naval Fortress in Estonia near Laagri. This is a remnant of one of the oldest large eruptions preserved. The diameter of the black camera lens cover is 58 mm (2.3 in). Volcanic ash is formed during explosive volcanic eruptions and phreatomagmatic ...
In essence, fractional crystallization is the removal of early formed crystals from an originally homogeneous magma (for example, by gravity settling) so that these crystals are prevented from further reaction with the residual melt. [3] The composition of the remaining melt becomes relatively depleted in some components and enriched in others ...
Pyroclasts include juvenile pyroclasts derived from chilled magma, mixed with accidental pyroclasts, which are fragments of country rock.Pyroclasts of different sizes are classified (from smallest to largest) as volcanic ash, lapilli, or volcanic blocks (or, if they exhibit evidence of having been hot and molten during emplacement, volcanic bombs).
Before the eruption, Aniakchak was a 2,300 meters (7,500 ft) high [117] deeply eroded stratovolcano [118] with two separate magma bodies, one andesitic and the other rhyodacitic, under Aniakchak at least 4.1–5.5 kilometers (2.5–3.4 mi) in depth. [63] These two magma bodies had evolved independently in the time before the eruption. [119]
A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upwards. [1] If the magma finds a path to the surface, then the result will be a volcanic eruption ...
VEI. 5. Impact. Buried the Roman settlements of Pompeii, Herculaneum, Oplontis, and Stabiae. Deaths. 1,500–3,500, possibly up to 16,000 [1][note 1] Of the many eruptions of Mount Vesuvius, a major stratovolcano in Southern Italy, the best-known is its eruption in 79 AD, [2][3] which was one of the deadliest in history.