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Friday, September 27, 2019

Write a short article about a major volcanic eruption Essay

Write a short article about a major volcanic eruption - Essay Example Volcanoes are powerful forces of nature. According to Ritter et al., volcanism is simply the manifestation of processes that occur in earth’s mantle on the surface of the earth (1). Rocks and minerals are liquefied into magma in earth’s mantle due to heat produced by extreme pressure. Weaknesses in the earth’s crust allow vents to form that allow magma to escape. This magma can emerge through the crust under the sea or on dry land. These vents will create three possible types of volcanic landforms. The type of landform is dictated by the mineral make-up of the magma that is expelled through the vent (2). Shield volcanoes, such as the Hawaiian Islands are made of magma that has low viscosity. It is mostly basalt and runs like water. Cone volcanoes are made of magma that is high in silica. The magma is sticky so it builds up making the steep sides of a cone shaped mountain. Similar to these are composite cones that are made of magma and ash. They are irregularly sh aped volcanic mountains. A final landform created by volcanoes is called a caldera. This is a huge empty space in the volcanic mountain created by a massive eruption. This is a prominent feature that was created by the eruption of Thera. The Greek island of Thera is located in the Mediterranean Sea just northeast of the island of Crete. The island is known in modern times as Santorini. The geologic shape and structure of the island is typical for volcanic islands in the Aegean and Mediterranean seas. The island was a mixture of ash and silica based materials with gentle slopes near the shoreline rising to an inland, conical peak. Thera had been slowly building for at least a million years. The current arrangement of the small islands of Santorini did not happen with just one eruption. As many as twelve eruptions over the past million years have made Santorini what it is today (3). The eruption that occurred around 1600 BC was,

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