Volcanoes what is a volcano the types
Examples of hotspots include Hawaii and the Portuguese island of Madeira, but for the most part, volcanoes lie at the edge of tectonic plates.
Most composite volcanoes have a crater at the summit which contains a central vent or a clustered group of vents.
Types of volcanoes wiki
Lava Domes: Volcanic or lava domes are created by small masses of lava which are too viscous thick to flow very far. Calderas range in form and size from roughly circular depressions 1 to 15 miles in diameter to huge elongated depressions as much as 60 miles long. They are usually large, steep-walled, basin-shaped depressions formed by the collapse of a large area over, and around, a volcanic vent or vents. Spectacular eruption from the Puyehue volcano in Chile. An interesting variation of a composite volcano can be seen at Crater Lake in Oregon. Lava domes are not just passive piles of rock; they can sometimes collapse and form pyroclastic density currents, extrude lava flows, or experience small and large explosive eruptions which may even destroy the domes! Geologists say it probably indicates that magma is again rising from below, and they suspect the area will erupt again. A spectacular eruption in Stromboli, Italy. Although the term is generally ascribed to basaltic shields it has at times been appended to rarer scutiform volcanoes of differing magmatic composition. They are caused by the fragmentation of gassy magma, and are usually associated with very viscous magmas dacite and rhyolite. This is the result of a stratovolcano collapsing into its magma chamber during a violent eruption. In northern California and Oregon, many shield volcanoes have diameters of 3 or 4 miles and heights of 1, to 2, feet. Let's take a look at how volcanoes form on Earth: Earth's crust is 3 to 37 miles 5 to 60 kilometers thick, according to the U. Lava domes, such as this example in the crater of Mount St. Helens , in Washington state, is a stratovolcano that erupted on May 18,
There can be active volcanoswhich are currently, or have recently erupted. The last explosive eruption left a funnel-shaped crater at the top of the cone. The essential feature of a composite volcano is a conduit system through which magma from a reservoir deep in the Earth's crust rises to the surface.
6 types of volcanoes
Volcanoes can and have existed on other worlds as well: although volcanoes on the moon and Mars have long been dormant, volcanoes are still very active on Jupiter's moon Io. Image adapted from cotf. Geological Survey. The floor of the ocean is more than 15, feet deep at the bases of the islands. Vulcanian eruptions may be repetitive and go on for days, months, or years, or they may precede even larger explosive eruptions. Calderas range in form and size from roughly circular depressions 1 to 15 miles in diameter to huge elongated depressions as much as 60 miles long. The cataclysmic ejected more than 1 cubic mile 5 cubic kilometers of material and buried a U. Here are some of the most common types of eruptions: Hawaiian Eruption In a Hawaiian eruption, fluid basaltic lava is thrown into the air in jets from a vent or line of vents a fissure at the summit or on the flank of a volcano. When a very large explosive eruption occurs which empties the magma chamber, the roof of the magma chamber can collapse forming a depression, or bowl on the surface which has very steep walls. Magma still feeds hot springs in the caldera.
Calderas: A caldera is a bowl-shaped depression formed when a volcano collapses into the void left when its magma chamber is emptied. As volcanic activity continues, perhaps over spans of hundreds of years, the cone is built to a great height and lava flows form an extensive plateau around its base.
Lava domes Volcanic or lava domes are formed by relatively small, bulbous masses of lava too viscous to flow any great distance; consequently, on extrusion, the lava piles over and around its vent.
They are usually large, steep-walled, basin-shaped depressions formed by the collapse of a large area over, and around, a volcanic vent or vents. Yellowstone caldera, sometimes called a "super volcano," is one example.
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