Kilauea Volcano - Geography Paper Example

Kilauea volcano is a shield volcano located south along the shores of Hawaii Island. It towers 1940 feet above sea level and covers approximately 14 percent of Hawaii Island. It forms part of the five volcanoes that constitute the island and is touted as the most active among the five. It still is an active volcano that dates back three to six hundred thousand years. It formerly existed as a submarine volcano before surfacing one hundred thousand years ago. Kilauea is a product of the Hawaiian hotspot and is regarded as the center of the seamount chain in Hawaii. It is not topographically prominent as it appears as a bulge along the island's shores and consists of a caldera which was formed recently at its summit. Mount Kilauea is characterized by 35 kilometers and 125 kilometers rift zones that are active in nature. Most parts of the mountain are still submerged as the mountain was formed on the sea floor. Kilauea consists mostly of lava flows that have solidified over time with scattered tephra and volcanic ash. It has remained relatively active throughout the years that it has been in existence for the longest time that the eruptions showed a slow down or inactivity being between 1934 and 1952. Most of its eruptions have occurred near or at its caldera at the summit of the mountain with some eruptions recently occurring at the rift zone located south of the mountain.

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FORMATION

Different scientists and geologists have come up with multiple theories of how the mountain was formed. Like many volcanic mountains, Kilauea was formed as a result of the Pacific Tectonic Plate moving over the Hawaiian hotspot within the mantle of the earth. Subsequent movements within and around the localized hotspot resulted in the generation of immense pressure and heat that eventually led to the formation of magma. The magma rose as a thermal plume through the crust and mantle and finally erupted on the ocean floor to form a seamount. Following a series of subsequent eruptions over thousands of years, the height of the seamount continued increasing breaking the ocean surface approximately 100000 years ago as an island volcano.

1983 ERUPTION

The 1983 eruption is the most recent of the major eruptions to have taken place on the island. It is also by far the eruption that has taken the longest duration beginning on the third of January 1983 along the rift zone located on the eastern side of the mountain. It resulted in voluminous lava flows that led to the formation of a cone known as Pu'u' O'o. A series of 61 eruptions have occurred on the mountain since 1983.

MAGMATIC PLUMBING SYSTEM

Research conducted on the magmatic plumbing system indicates that the process consists of four stages namely the pre-shield stage, the shield stage, post-shield stage and the rejuvenated stage. In the pre-shield stage, the melting of the mantle is to a smaller degree leading to a smaller supply of magma. This phase is characterized by the eruption of basanite and basalt.

During the shield stage, the melting of the mantle occurs at a higher degree leading to the formation of voluminous magma. This stage leads to the formation of over 95 percent of volcanic ash and edifice. The amount of magma reduces during the post-shield stage due to a reduced degree of mantle melting. This stage is closely associated with compositions such as trachyte and mugearite. The final stage, also known as the post-erosional stage results in the formation of the least amount of magma with the lowest degree of melting mantle among the four stages. Nephelinite and alkalic basalt are the main constituents that constitute this stage.