Volcanic Eruption Causes
Earth is very much hot inside, so that some rocks slowly melt and convert into a thick flowing substance, which is called magma. Magma is lighter than the solid rock, magma rises and some of the magma erupted through vents and fissures to the Earth's surface. Which is called volcanic eruption and erupted magma is called lava. there are several factors for triggering a volcanic eruption some of these are, the pressure from the dissolved gases in the magma, the injection of a new batch of magma into an already filled magma chamber and the tectonic plates are pushed down another tectonic plate.
Formation Of Lava Deposition Landforms
Volcanic landforms Formation are the geological processes, which is depends on the eruptive behavior of the volcano. After eruption of the volcano, the volcanic Lava cold down and formed the original landform. volcanic landforms modified according to lava materials. There are many different types of volcanic landforms like,
Shield Volcanic Landform
Shield volcanoes are formed by the lava flows over a central vent. shields contain low viscosity basaltic magma. Due to low viscosity of the magma, lava travel down in a gentle slope. shield volcanoes is in a roughly circular or oval shape. Hawaiian volcanoes, Kilauea and Mauna Loa are the example of Shield Volcanoes.
Strato Volcanic Landform
Strato Volcano Landform is in higher steeper slopes than shield volcanoes, with 6 to 10 degree slopes on the flanks and 30 degree near the top. 50% Pyroclastic material is in Strato Volcano Landform.
Cinder Cones Or Tephra Cones Volcanic Landform
Cinder cones are in small volume. They are from by strombolian eruptions and consist basaltic to andesitic material. Cinder Cones Slopes are between about 25 and 35 degree. Cinder cones occur in a groups of tens to hundreds of cones in one area. Paricutin Volcano in Mexico is the example of cinder cone.
Volcanic Domes Or Lava Domes Landform
Volcanic Domes occur due to the extrusion of highly viscous gas with poor andesitic and rhyolitic lava. Due to the high viscosity the lava does not flow away from the vent, and piles up near the vent. Volcanic Domes contain more gas rich magma, they can be extremely dangerous after eruption.
Craters and Calderas Volcanic Landform
Craters are circular depressions, due to volcanic explosions, within the range of 1 km in diameter. Calderas are circular to elliptical larger depressions in the diameters of 1 km to 50 km. Calderas form due to collapsing a volcanic structure. Calderas collect rain water and snow melt, and form lakes. 8 km diameter Crater Lake Caldera in southern Oregon is a example of Calderas. million years ago Larger calderas have formed in the western United States, including Yellowstone Caldera in Wyoming, in eastern California Long Valley Caldera, and Valles Caldera in New Mexico.
Plateau Or Flood Basalts Landform
Plateau or Flood basalts are made up of low viscosity basaltic magma from fissure vents, in extremely large volume and spread in huge areas with low slope and build Plateau Or Flood Basalts Landform. in Iceland the Laki basalt is the example of Plateau Or Flood Basalts.
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