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Volcanoes Natural processes & factors that create volcanic environments Volcanoes can be classified by the severity of their eruptions, which are usually.

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Presentation on theme: "Volcanoes Natural processes & factors that create volcanic environments Volcanoes can be classified by the severity of their eruptions, which are usually."— Presentation transcript:

1 Volcanoes Natural processes & factors that create volcanic environments Volcanoes can be classified by the severity of their eruptions, which are usually named after famous volcanic explosions from the past or by the region they are usually associated with, or by their physical attributes. Several classifications by severity are:

2 Hawaiian Volcanoes little lava flows from small vent

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11 Icelandic Volcano-lava gently flows on generally flat surface

12 Krakatoan Volcano- extremely violent, often causes its peak to detach

13 Strombolian: small, frequent eruptions

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15 Volcanian: less frequent, more violent Strombolian eruptions

16 Vesuvian: violent eruptions after long periods of inactivity

17 Pelean: powerful eruptions followed by flowing glowing lava

18 Plinian: large amounts of lava and pyroclastic are ejected

19 VOLCANIC LANDFORMS In addition to the first classification, volcanologists also group them into five major categories: Basic or shield volcanoes Basic or shield volcanoes have broad, gentle slopes, similar to a warrior's shield, built from the buildup of cooled basaltic lava over thousands of years. They usually have nonviolent eruptions, letting its fluidic lava flow out in all directions from its vent or vents.

20 Acid or dome volcanoes Acid or dome volcanoes tend to have craggy, steep- sloped sides covered with rock debris. Its eruptions are characterized by viscous lava explosions, which allow its lava to flow for great distances and to spill over and around its vent. The increase in temperature causes the dome to expand while its outer lava cools. This growth causes the newly hardened surface to splinter, causing loose debris to fall from its sides, the reason for its appearance. These volcanoes are typically found near large composite volcanoes.

21 Cinder and scoria volcanoes The cinder and scoria volcano, also called ash and cinder, is the most basic type of volcano, with a round crater at its summit. The cinder or scoria is the result of gas- charged lava cooling in the air during an eruption. Such volcanoes usually never surpass a height of 1000 ft.

22 Composite volcanoes or stratovolcanoes Composite volcanoes or stratovolcanoes are one of the most majestic mountains in the world. At a staggering height of 8,000 feet above sea level, no other volcano can tower over these beauties. However, a rose does have its thorns. These volcanoes have explosive eruptions, with lava flowing from a crater in its summit, enough to damage whole cities. Composite volcanoes are known for its unique system of tunnels through which magma flows to the crater.

23 Caldera volcanoes Caldera is a bowl-shaped volcano depression, usually at least a mile in diameter. Despite its meek appearance, calderas are actually the most explosive of them all, having the force of several nuclear explosions. Hot springs, geysers, and such can be found near a caldera.


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