Volcanoes

A volcano is a structure containing a beam or cluster fed by magma rising even out off from great depth within the earth. The level of hazardousness of a volcano can be determined by both(prenominal) human and physical factors. Physical factors include viscousness of lava, home margins and geek of materials ejected, whereas human factors argon proximity to population centres and predictions, forecasts and reactions. viscousness of lava determines the nature and index of volcano, which causes some volcanoes to be more hazardous. Temperature, te dioxide content and amount of gases can reckon the viscousness of lava. Temperature; the mel dis articulateeded the temperature, the cut back the density and the more easily it go out flow. silicon dioxide content; the broad(prenominal)er the silica content, the more viscous the lava give be. Amount of gases; the greater the amount of dissolved gases, the more limpid the lava. Two types of lava are basaltic (basic) and andesitic (acidic) lava. Basaltic lava which is produced by upwards journeyment of material from mantel is usually at divergent exfoliation boundaries and hotspots. It is low in silica content, has low viscosity and high fluidity. Andesitic lava is produced by the subduction of oceanic crust into asthenosphere, found at the rim of the oceanic plate. It has a higher silica content, high viscosity and flows slowly.

An good example of a basaltic lava volcano (shield volcano) is Mauna Loa in Hawaii. An example of andesitic lava volcano is Mt St Helens in USA. Thus, we know that the viscosity of lava affects the power of volcanoes and how hazardous it! can become. Plate margins can affect the type of eruption, thus, causing some volcanoes to be more hazardous. Volcanoes are more often than not found along two types of plate margins reconstructive and destructive. At constructive plate margins, upwelling of magma cause overlying plates to move away from one another. Basaltic lava is thus produced by the partial(p) melting of the mantle deep below the surface. Therefore, it has a low viscosity and is associated...If you call for to get a full essay, order it on our website: OrderCustomPaper.com

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