The Volcanic Eruption Of Volcanoes

1984 WordsJun 10, 20178 Pages
Geologic Processes Volcanoes are one of the most beautiful and yet destructive forces naturally occurring on our planet. As the Earth’s population continues to grow, more people move closer and closer to volcanoes. Currently, an estimated 500 million people from Japan to Indonesia, and from Italy to Oregon, live near active volcanoes. Each year, approximately 70 volcanoes will erupt, and usually at least once every ten years, there will be a large volcanic eruption that puts the people living both near and far in danger (Lutgens & Tarbuck, 2005). As populations continue to increase and more people are attracted to the beauty surrounding these areas, the number of people choosing to beauty of an area over the known dangers of living…show more content…
While we typically think of the pressure being released in a dramatic eruption from a volcanic mountain that has been formed, the pressure can also be released as magma quietly escapes through fissures, or cracks within the ground near the volcano. This process is referred to as fissure eruption. Once the magma is released from the volcano, it is called lava. Fissure eruptions can occur over a wide area, but over a few hours or days, they typically become a central vent from which the pressure will continue to be released. Occasionally, lava will flow back into the ground by pouring into a crack or an open eruptive fissure, a process called drainback. Lava can also flow back into the same fissure from which it erupted (Krock, 2002). Regardless of where the lava flows, the change in the terrain is called a lava plateau. These lava plateaus can be relatively small or very large. For example, the Columbia plateau covers an area more than 150,000 square kilometers and extends over the states of Washington, Idaho and Oregon (Landscape America, n.d.). Two materials make up a volcanic eruption: lava and ash. However, each volcano can have different proportions of lava to ash. Volcanoes in Hawaii and the Galapagos are mostly lava (greater than 95%) with just a small (less than 5%) ash, typically in the form of cinder (Oregon State University, n.d.). Other volcanoes may have more cinder ash than lava. Are All Volcanoes the Same? Volcanoes come
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