The negative impact / danger of volcanic eruptions are as follows: Impact of volcanic eruptions can influence directly or indirectly and nature can be destructive (negative) or a blessing (positive) to the surrounding community. Volcanic eruptions can cause various effects or results. Continental crust position is on top of the oceanic crust due to differences in specific gravity, and both floats on astenosphere. 7 km), is more dense and is not older than 200 million years. Continental crust has lk.35 km thick, low-density and age of 1-2 billion years, while the oceanic crust is thinner (lk. Astenosphere weaker section occurs at or near the temperature at which melting starts to happen, as the result some parts of astenosphere melt, although most are solid.
Litosphere moves pedestal above the zone of weak upper mantle, which is also called astenosfir. Plates move each other and also penetrate into the mantle convection. Lithosphere includes the crust, generally has a thickness of 70-120 km and split into several large fragments called tectonic plates.
In the upper mantle, about 7-35 km below the earth, these materials cools and becomes solid, then sinks again into the convection flow. Propagation of heat from the earth to the surface is in the form of convection, where the materials are heated on the base coat, the depths of 2,900 km below the earth, moves and narrowed spreads around. The cooling occurs due to the release of heat and intensity vulcanisme on the surface. Formed by the earth during hot temperature, but then cooled gradually in accordance with its historical development. The heat inside the earth is hot formed during the formation of the Earth about 4.5 billion years ago, along with the heat arising from natural radioactive elements, such as elements of the isotope K, U and Th with respect to time.
Both these factors greatly influence the formation and composition of the magma and the locations and volcanic events. Earth has a lot of fluids and water on the surface. Knowledge of plate tectonics is the beginning of solving the puzzle of natural phenomena including mountain ranges, continental, earthquakes, and volcanoes. Magma chamber is driven by rock resulting magma volume increases and is eventually emerged as the eruption. This happens under, in, and above the magma chamber. Volcano may erupt as a result of increased mobility bouyancy and magma body.
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