Formation of Volcanoes on Earth and Other Planets - Report Example

Introduction When the earth crust is ruptured because of several reasons, it forms a volcano; this rapture allows hot lava and volcanic ash from the inner part of the earth to escape out. Volcanic eruption takes place on the earth because the crust of the earth is divided into seventeen main rigid tectonic plates believed to be floating on hot soft layer in the mantle. That is the reason why volcanoes on earth are mainly found where tectonic plates are divergent or convergent. An example is that, in the Atlantic Ocean, there is a mid-oceanic ridge which has caused the formation of volcanoes as a result of divergent tectonic plates moving away from each other (Edmond and James 4). In the Pacific Ocean, the inner earth forces cause divergence of pacific ring of fire resulting in the formation of volcanoes in the Pacific Ocean. In places where crust interior plates stretches and compress, it results in the formation of volcanoes. An example is in east Africa rift. Volcanoes are formed as a result of movement of tectonic plates on the earth crust and extrusion of magma from the inner part of the earth. Inner part of the earth The inner part of the earth is made up of two cores, inner and outer core, after the core is a highly viscous mantle and the solid crust. The outer core is liquid while the inner is solid. The high temperatures and pressure inside the earth make the mantle to be in viscous state. Inside the earth, the rocks found in the mantle and core are still hot after the earth was formed billion of years ago. According to the scientist, as the earth was being formed, the materials that make up the earth collided at high speed, the high speed collision generated heat and it remains trapped inside the earth while the surface cooled (Haraldur and BHoughton 36). Apart from that, radioactive elements within the earth produce heat through radioactive decaying. Since the earth is large, the radioactive elements produce a lot of heat and it is shielded from reaching the earth surface by rocks, rocks are well known to be good insulators. The heat is capable of melting certain rocks found at the upper mantle. Rocks at that layer are made up of several minerals and each mineral has its own boiling point that means when a rock starts to melt, some minerals melts faster than others (Haraldur and BHoughton 36). Formation through volcanic eruption When a rock melts and forms liquid or semi-liquid, its density becomes less as compared to the surrounding rocks. Due to the difference in density, the magma is pushed upward by pressure, the heat resulting from this pressure melt some rocks on the way. The molten material look for a way into the earth surface through cracks resulting from weak points, it exert pressure on the cracks so as to escape (Haraldur and BHoughton 36). As it moves upward, sometimes the downward pressure exceeds the downward pressure forcing the magma to collects forming magma chambers. If a crack opens up or pressure becomes too much in the chambers, the magma spew out of the chambers. When it reaches the earth surface, the magma is then referred to as larva; the larva will then form volcanic mountains after cooling. The mountains may grow bigger because some volcanoes erupt severally after a certain period of time forming different layers. Weak points between the magma and the earth surface enable eruption; the outburst of magma is sometimes accompanied by strong earthquakes. The flow of magma is determined by things such as pressure, amount of gas, and mineral content. When there is an eruption, large chunks of rocks, red-hot ash, and large fiery clouds is seen on the mountains. They normally come through the central vent and in some occasions the central branch may form branches and it eject the larvae through the sides of the mountain. The structure of the formed volcanoes and the eruption intensity rely on several things such as the composition of the magma. (Gillian and Donna 9) Eruption of magma The eruption power of volcanoes varies greatly, some erupt violently causing a lot of destructions while others erupt silently by sipping out larva safely, and this diversity depends on the type of magma. Magma is made up of many dissolved gases that are suspended in the solution. The gases remain dissolved in that state so long as the pressure exerted by the surrounding rocks is higher than the vapor pressure of the magma (Gillian and Donna 9). When the pressure changes and vapor pressure becomes greater than the confining pressure, the gas will then expand and it forms small gas bubbles known as vesicles in magma. This bubbles is what causes eruption, an example is soda when it is opened. As this bubbles escape to space from the ground, they push magma out causing a spewing eruption. The strength of the eruption depends on the viscosity and content of the bubbles. When the magma has high viscosity, it will resist the flow and it will make it hard for the gas bubbles to escape, which means it is going to push more materials causing a violent eruption (Gillian and Donna 9). If less gas bubbles are contain in the magma, it will erupt calmly but if it contains a lot of gas bubbles it will erupt violently. When the magma viscosity and amount of gas it contains are low, the eruption will be calm. The areas that are formed by mantle plumes is normally called hotspots, this are areas that contain hot material that originates from core mantle boundary. The earth tectonic plate’s moves across this columns, when it passes it, the volcano becomes dormant and when a volcano reaches again this place it is reformed and it then becomes active volcano (Anita 24). (Neil and Moretti 94) Types of eruption There are many types of eruptions and the main ones are; Plinian eruption. This is a violent eruption and it can cause a lot of damages to the surrounding community (Anita 24). Hawaii eruptions are not destructive; they produce sluggish flow of magma. Strombolian eruption is impressive but not dangerous. They spew lava in short bursts. They do not produce lava flows and they produce a small amount of ashy tephra. Formation through plate tectonics Tectonic plates are always in motion because they sit on top of liquid or semi liquid materials. The movement is very slow it takes long time before being noticed, though they are in constant motion (Neil and Moretti 94). The formation of volcanoes takes place irrespective of the direction in which the plates is moving to, whether they are moving towards each other or moving away from each other. The plates are always in collision and due to extreme pressure, one plate may slide over the other and stays at the top, the other plate will then be forced into the mantle. In this case of convergence, the places where the two plates meet is called subduction zone. When two oceanic plates collide, one will submerge under continental plate hence creating a deep ocean trench on offshore (Neil and Moretti 94). Through a process known as flux melting, the water that comes out of the subducting plate will then bring down the melting temperatures of the overlying mantle, this will create magma. The magma created is very viscous as a result of high content of silica. When this magma reaches the surface, it forms volcano. The mountains formed as a result of this process is Mount Etna. In the middle of the oceans, tectonic plates move away from one another and a new ocean crust is formed through cooling and solidifying of lava (Neil and Moretti 94). Since the ocean crust is thin at the ridges because of the bull in tectonic plates, when the pressure is released, it leads to adiabatic expansion and incomplete melting of the mantle, and this will cause volcanism. Divergent plate boundaries are normally found at the bottom of the ocean which means most of the volcanoes formed as a result of this process are submarine. Conclusions The inner part of the earth is made up of two cores, inner and outer core, after the core is a highly viscous mantle and the solid crust. The outer core is liquid while the inner is solid. The high temperatures and pressure inside the earth make the mantle to be in viscous state. The heat inside the earth is capable of melting certain rocks found at the upper mantle. The earth crust is made up of seventeen main rigid tectonic plates that are floating on solid and semi-solid layers. The volcanoes are formed through volcanic eruption and movement of tectonic plates. In volcanic formation, the rocks melt and form liquid or semi-liquid materials know as magma, its density becomes less as compared to the surrounding rocks. Due to the difference in density, the magma is pushed upward by pressure, when it reaches the surface of the earth it forms volcanoes. In the formation through movement of tectonic plates, the plates are always in collision and due to extreme pressure, one plate may slide over the other and stays at the top, the other plate will then be forced into the mantle hence forming volcanoes. Works cited Foulger, Gillian R.,Jurdy, Donna M.,eds. Plates, Plumes, And Planetary Processes. Boulder, Colo.: Geological Society Of America, 2007. Print Mahony, S. H., et al. "Volcano-Tectonic Interactions During Rapid Plate-Boundary Evolution In The Kyushu Region, SW Japan." Geological Society Of America Bulletin 123.11-12 (2011): 2201-2223. GeoRef. Web. 15 Sept. 2014. Mathez, Edmond and A.Webster, James D.The Earth Machine: The Science Of A Dynamic Planet. New York: Columbia University Press, 2004. Print. Sigurdsson, Haraldur, and Bruce Houghton. Encyclopedia of Volcanoes. San Diego: Academic, 2000. Print. Earthquakes, Volcanoes, and Tsunamis: Resources for Environmental Literacy. Arlington, Va: NSTA Press, 2007. Print. KOYAGUCHI, T, and A.W WOODS. "On the Formation of Eruption Columns Following Explosive Mixing of Magma and Surface-Water." (1996). Print. TURNER, S.P, R.M.M GEORGE, P.J EVANS, C.J Hawkesworth, and G.F ZELLMER. "Time- scales of Magma Formation, Ascent and Storage Beneath Subduction-Zone Volcanoes." (2000). Print. van, Wyk V. B, A Márquez, R Herrera, J L. G. Bruña, P Llanes, and A Delcamp. "Craters of Elevation Revisited: Forced-Folds, Bulging and Uplift of Volcanoes." Bulletin of Volcanology : Official Journal of the International Association of Volcanology and Chemistry of the Earth`s Interior. 76.11 (2014): 1-20. Print. Ganeri, Anita. Eruption! The Story of Volcanoes. New York: Dorling Kindersley Pub, 2000. Print. Lewis, Neil, and Antonio Moretti. Volcanoes: Formation, Eruptions and Modelling. New York: Nova Science Publishers, 2009. Internet resource. Read More