Types of Volcanoes
Let us understand about Volcanoes
- Volcanoes are the gap within the layer through which gases, melted rocks material (Lava), Ash, Stream, etc are emitted outward, is that the course of the outburst. Such vents or openings occur in those parts of the planet’s crust wherever the rock strata are comparatively weak.
- The word volcano is derived from Vulcano, a volcanic island in the Aeolian Islands of Italy whose name, in turn, comes from Vulcan, the god of fire in Roman mythology. the study of volcanoes is called Volcanology.
Let’s come on to classification-
- Volcanoes are classified based on their nature of eruption and the form developed at their surfaces.
Let’s take a look at the world’s most famous volcanoes and their locations-
- Shield volcanoes are the largest of all volcanoes on the earth these volcanoes are mostly made up of basalt which is the type of Lava that is very fluid when erupted.
- These volcanoes become explosive if somehow water gets into them otherwise, they are characterized by Low-explosivity.
- The upcoming Lava moves in the form of a foundation and throws out the cone at the top of the vent and develops into a cinder cone.
- The major examples of shield Volcanoes are- Hawaiian Volcanoes, Prospect Peak, Belknap Crater, Galapagos Islands, etc.
- These volcanoes are the most explosive of the earth’s volcanoes.
- They are usually so explosive that when they erupt they tend to collapse on themselves rather than Building any tall structure.
- Collapsed depressions are called calderas. Their explosiveness indicates that the magma chamber supplying the Lava is not only huge but is also in a closer vicinity.
- Since 1900, only seven calderas have occurred till now and the most recent occurred was at bardarbunga volcano in 2014.
- The major examples of Caldera Volcanoes are – Mount Meru, Mount Elgon, Long Valley Caldera, Yellow stone caldera, etc
- Composite volcanoes are characterized by eruptions of cooler and more vicious Lavas than basalt.
- These volcanoes result in explosive eruptions along with large quantities of pyroclastic material and ashes that find their way to the ground.
- These materials accumulated in the vicinity of the vent openings leading to the formation of layers and this makes the mounts appear as composite volcanoes.
- The Major composite volcanoes are- Mount Fuji in Japan, Mount Shasta in California, Mount St. Helens in Washington and the major volcano chains are Pacific Rim which known as the Rim of Fire.
The most volcanoes on earth are in the ocean.
Hawaii is the home of earth’s biggest volcano on land mauna loa.
Mid Ocean Ridge Volcanoes
- These volcanoes occur mostly in oceanic areas. There is a system of Mid-ocean ridges more than 70,000 km long that stretches through all the ocean basins.
- The central portion of this ridge experiences frequent eruptions.
Flood Basalt Provinces
- These volcanoes outpour highly fluid Lava that flows for long distances. they are the result of landmasses due to thick basalt lava flows for long-distance.
- There can be a series of floors with some flows attending thickness of more than 50m.
- Individual flows may extend for hundreds of kilometres.
- The major examples of flood basalt provinces are- Deccan Traps of India, Siberian traps, etc.
Major abundant volcanic gas -Water Vapour
Other important gases- CO2, SO2.
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Volcanoes can be Active, Dormant or Extinct depending upon the nature of eruption.
Active volcanoes erupt regularly or have erupted in the recent past or may erupt in the future, there are five hundred active volcanoes and the majority of them are in the Pacific Ocean which is called Pacific Ring of Fire. Mount Fuji in Japan and Mount Vesuvius in Italy are examples of active volcanoes.
Volcanoes that may erupt in future are called dormant volcanoes. for example- Trou aux Cerfs in Mauritius, Mount Edziza in Canada, Mauna Kea in Hawaii, the United States etc.
Volcanoes that have stopped erupting because they no longer have Lava supply are known as extinct volcanoes. for example- Ben Nevis, Waw- an-Namus in Lybia etc.
Source of materials like metals, precious germs, construction materials etc.
Power generation-Geothermal and hydroelectric opportunities.
Rich volcanic soils-The best coffee grows in volcanic soils.
Ash causes respiratory problems and triggers lightning.
H2O( Water vapour) largest contributor to greenhouse gas effect on earth.
CO2 (Carbon dioxide) Contributes to global warming.
SO2 (Sulfur Dioxide) Dissolves in water vapour to form damaging acid rain.
Parts of volcano
- Ash Cloud
- Parasitic Cone
During, eruption Ash and rock are thrown high. When Mt. Vesuvius erupted in 79AD the ash cloud was 20 miles high and it was entered the stratosphere.
The magma becomes lava once it reaches the surface of earth. Lava forms igneous rocks, such as granite as it cools.
A parasitic cone forms when magma breaks through the surface of volcano. Parasitic cone is cone-shaped accumulation of volanic material.
The Crater of the volcano is the opening caused by volcanic activity. At the time of eruption, magma rises out of the crater.
Every Volcano has a center vent. It is the opening that allows magma to travel from the earth’s crust to the crater.