Monday, February 24, 2020
The Volcanic Island Arcs of the Pacific Term Paper
The Volcanic Island Arcs of the Pacific - Term Paper Example (Akusekijima) near Pacific. Iriomotejimi: In the north of Iriomotejimi Island, submarine volcano is present. This volcano is located 25 km north north east (NNE) at the tip of Iriomotejimi island. The estimated depth of the area where this island is located is about 200 to 300 meters. A major eruption took place at this volcanic island in 1924. The after effects of this eruption were terrible. The pumice rafts produced with this eruption had total volume about 1 cu km. This was carried away by water currents along the whole coast of Japan as far as Hokkaido situated in the north. The largest block formed by melted concrete also known as pumice blocks exceeded up to 1x2 meters in size. The volume of eruption proved to be the largest among all the historical eruption. The largest volume made this outbreak volcanic explosion as the largest in JapanÃ¢â¬â¢s history. Kikai Caldera Kikai Caldera is a massive volcano up to 12 miles in diameter. This volcano is located in Osumi islands in J apan. This volcano is the remain of ancient volcanic eruptions took place thousands years ago. Akahova eruption is directly connected to Kikai Caldera. This eruption is considered one among the largest volcanic eruptions took place during Holocene ten thousand years ago. The consequences of this volcanic eruption prolonged and about six thousand years ago, pyroclastic flows from that outbreak and the magma reached to the southern coast of Kyushu. This flow extended over an extensive area up to 62 miles away. The ash could be felt at distant areas. This eruption further produced round about 150 cubic kilometers of tephra. The Volcanic Explosivity Index was 7 due to this massive explosion. So, the ongoing conditions made this one of the most destructive and explosive in last 10, 000... The term paper "The Volcanic Island Arcs of the Pacific" talks about the Pacific tectonic plates all along the boundary situated in the West. These plates move under another and sink into the mantle of the Earth. As a result subduction zones establish in broad curves and island chains develop along these zones. These chains are known as island arcs. Islands are formed due to these volcanic activities but at the same time, there might be several other reasons. Flexing plates, sometimes, up to warp the floor of the sea, lifting it out and form islands. Moreover, if subducting plate has plentiful sediments then these sediments may be slipped off to overriding plates. This scrapped sediment portion builds up into a wedge which is called mÃ ©lange. Sometimes this wedge may put up so much that it converts into a ridge. This ridge further dominates the forearc. For arch is the region present in between the trench axis and island arc. When tectonic forces apply to these forearcs, they get uplift and the ridges are also uplifted and form islands. Examples of such types of islands include Yap, Guam, and Eua. The Kuril Islands formed volcanic arc composed of 45 volcanoes present on 20 islands. The Pacific Plate shifts with great velocity. This speed is about 90 mm per year. The Pacific plate subducts under Okhotsk Plate near Kuril trench. Here it goes deeper in a northwest direction. This area is seismically very active to a depth of about 680 km. the volcanoes present here are heated up with melted magma.