Volcanoe Erupting

A Graph Of A Volcanoes

How do Volcanoes erupt?

Volcanoes are formed when there is a great stress inside the earth’s crust and the pressure of magma reaches so high that it finds its way upward causing an eruption. Sometimes the magma chamber breaks its sides and only reaches to the flank or summit of volcano and sometimes reaches to the surface causing an eruption. In the volcanoes which are not much active supply the magma from the deeper parts of the earth is not sufficient to cause eruption so most of the times crystals forms and they go down at the bottom releasing gas in the form of bubbles which come to the top of chamber and sometimes the pressure created by these gas bubbles are enough to erupt a volcano or just wait there for a little more push which they get from the next new magma formed within the earth. The heat just triggers the magma for eruption which was there for a long time.Magma chambers are located very close to the surface and usually just under the volcano. The pressure of the cooler earth at the crust keeps it there, but the magma is still hot. As mentioned before, some of what makes up magma are gasses. These gasses are constantly expanding, and since they are the least dense part of magma, they contribute the most pressure that presses against the earth. The gas forms bubbles that expand and rise to the top of a magma chamber. When the pressure from them gets to be more than that of the earth around the magma, cracks form and the magma is able to escape, causing an eruption. If the earth is very weak or thin, the pressure can cause it to explode, sending magma--called lava above ground--and rocks into the air. These are the more powerful eruptions that are seen. The magma dries quickly when exposed to the cool air, hardening and eventually stopping more magma from spewing out.

What are the effects of volcanoes?

A volcano is actually an opening or a fissure, in the earth' crust , through which lava or molten rocks, ash and toxic gases present below the surface of Earth, are discharged by a sudden, violent eruption. Sometimes, it can be a mountain like structure with a bowl shaped depression at the top, through which these substances are expelled. The term volcano, is derived from the name of the Roman God of fire, Vulcan. Volcanic structures are usually formed at places where the tectonic plates are either converging or diverging. A stretching or thinning of the Earth's crust, can also lead to the formation of volcanoes. They are often classified into three types, on the basis of their frequency of eruptions, i.e. active, dormant and extinct. The active volcanoes are characterized by regular eruptions, while the dormant volcanoes are those that erupted in the past, but are silent now. On the other hand, an extinct volcano is the one that erupted in the remote past and is unlikely to erupt again.

Why Do Volcanoes Erupt?

When rock inside the earth becomes hot enough it melts. This molten rock,or magma,is less dense than water will float on water, the relatively low density of the magma causes it ti rise to the surface of the earth. If the magma contains water and dissolved gasses, when the magma reaches the surface the water and dissolved gasses will suddenly expand into stream and gas,causing a violent eruption. Volcanic eruption are among  the Earth's most powerful and destructive forces. The Earth's first ocean and atmosphere formed from the gases given off by volcanoes. Volcanoes have also shaped the Earth's landscape. Many of our mountains,island, and plains have been built by volcanic eruption.