Ganesha Special Hindu Mythological Information Site Of Pictures,Online Worship Of Gods,Saints,Greeting-Cards & Audio
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Ganesha Special Hindu Mythological Information Site Of Pictures,Online Worship Of Gods,Saints,Greeting-Cards & Audio |
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Information The word volcano,is derived from Vulcano, a volcanic island in Italy whose name comes from the name of a god of fire,Vulcan, in Roman mythology. The study of volcanoes is called volcanology.A volcano is an eruption of molten rock blasting up from the planet's interior strata,throwing out the lava and poisonous gases.A volcano consists of a magma chamber,pipes and vents.The magma is deep within the planet ground,pipes are the channels leading to the surface vents ,through which lava is ejected during the volcanic eruption. The volcanoes those erupt regularly called active, wheras those erupted in olden times and are quet now,are called dormant.Those which have not erupted in ancient times are called extinct.The lifespan of a volcano can vary from months to several million years.Many of Earth's volcanoes have erupted dozens of times in the past few thousand years but are not currently showing any signs of eruption.The volcanoes which are suppressed and not getting errupted,become restless and cause earthquakes. Scientists usually consider a volcano active if it is currently erupting or showing signs of unrest, such as unusual earthquake activity or significant new gas emissions.The Yellowstone Caldera in Yellowstone National Park is at least 2 million years old and not yet erupted violently for approximately 640,000 years.For this reason, scientists do not consider the Yellowstone Caldera extinct. Since there are frequent earthquakes at Caldera and rapid rates of ground uplift,it is considered as an active volcano.
The Earth's Moon has no large volcanoes, but has many volcanic features.The planet Venus has a basalt surface which shows that volcanoes have played a major role in shaping its surface. Changes in the planet's atmosphere and observations of lightning, have been attributed to ongoing volcanic eruptions. Effects of volcanoesVolcanic activity is many times followed by earthquakes, hot springs,mud pots and geysers.Minor earthquakes often precede eruptions.
Shield volcanoeThe name comes because of the shield-like profiles, formed by the eruption of lava which can flow a great distance from a vent.Shield volcanoes are more common in oceanic than continental settings. SupervolcanoIt is a large and most dangerous volcano that causes devastation on continental, scale.The huge sulpher and ash produced in such volcanoes give rise to excesive cooling of eart temperature. Submarine volcanoThese volcanoes are common on the ocean floor which errupt steam and rocky debris high above the surface of the sea.These volcanoes when become very large, break the ocean surface as new islands.The Pillow lava is a common eruptive product of submarine volcanoes. Subglacial volcanoThis volcano develops under the icecaps which is made up of flat lava and flows on the top of extensive pillow lavas. When the icecap melts, the lavas on the top collapse, leaving a flat-topped mountain.Examples of this type of volcano can be seen in Iceland. Mud volcanoThis is a formed by the excreation liquids and gases from th eground.The largest structures are 10 kilometers in diameter and reach 600 meters high.
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