EVS1001 T 5:30
March 26th 2013
In this essay I will describe how volcanoes affect our environment. They both positively and negatively impact our world. I lived on the big island of Hawaii for a while, and got to experience firsthand the power of the volcanoes. I walked through lava tubes, dormant craters, and even watched red hot lava slither down the side of Kilauea and into the Pacific Ocean. They have fascinated me ever since.
What is a volcano? “Volcanoes are awesome manifestations of the fiery power contained deep within the Earth.” (National Geographic) Earth has an inner temperature equal to the sun’s surface. A volcano is a vent or an opening on the surface of the earth’s crust that allows hot magma, volcanic ashes and gases to escape from below the earth’s surface. This usually happens where the tectonic plates are diverging or converging, but can also appear where the earth’s crust is thin and stretched. Tectonic plates are the large scale motion of earth’s lithosphere. An eruption happens when thick magma and large amounts of gas build up under the surface. During a volcanic eruption, lava, tephra (ash, lapilli, volcanic bombs and blocks), and various gases are expelled from a volcanic vent. “The mountain-like mounds that we associate with volcanoes are what remain after the material spewed during eruptions has collected and hardened around the vent.” (National Geographic) This can happen rather quickly over a few weeks, or it can happen very slowly over millions of years.
How does this affect our environment? Volcanoes in the populated area pose a serious threat to human lives because they are often associated with earthquakes. Flows of searing lava, which can reach 2,000 degrees Fahrenheit (1,250 degrees Celsius) or more, can be released, burning everything in its path, including whole towns. Boulders of hardening lava can rain down on villages. I got see the remains of a small town near Hilo, that had been...