Earth Science - Other

Hawaii Islands

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The Hawaiian Islands form an archipelago of nineteen islands and atolls, abundant smaller islets, and undersea areas making a way from the northwest by southeast in the North Pacific Ocean between latitudes 19 N and 29 N. The archipelago takes its name from the largest island in the group and goes over 1500 miles from the Island of Hawaii in the south to northernmost Atoll called Kure.

This archipelago presents the uncovered peaks of a undersea mountain range which is called the Hawaiian Emperor seamount chain. This seamount was formed by volcanic motion over a hotspot in the earth's layer. At 3,000 km from the nearest continent around, the Hawaiian Island archipelago is the most desolate group of islands on Earth.The Hawaiian Islands are also a habitat to a large number of species since they were formed. The plant and animal life of the Hawaiian Islands developed in nearly absolute isolation over 70 million years.

Polynesians were the first human contact to the islands and introduced new trees, plants and animals. The growing inhabitants also brought deforestation, forest degradation, and environmental degradation. As this was in effect many species that depended on forest and its nourishment went extinct. The formation of these islands is rather intricate and it takes one to think on how they were actually created. The chain of islands formed as the Pacific plate moves slowly northwestward over a hotspot in the Earth's layer at 32 miles per every million years.

Thus, the islands in the northwest of the archipelago are older and naturally smaller. This is possibly because of the longer exposure to corrosion.The only active volcanism in the last 200 years has been on the southeastern island of Hawaii and on the flooded but still growing volcano at the southeast.

The Hawaiian Volcano Observatory of the U. S. Geological Survey documents current volcanic activity and provides images and charts of the volcanism. Almost all of the magma created in the hotspot has the arrangement of basalt. And so the Hawaiian volcanoes are constructed almost entirely of this certain rock and its equivalents which are gabbro and diabase. A few igneous rock types with compositions unlike basalt, such as nephelinite, do arise on these islands but is does not happen often at all.

The bulk of eruptions have basaltic magma and is relatively flowing compared with magma that is usually involved in more unstable eruptions such as the andesitic magmas that construct some of the dangerous eruptions around the margins of the Pacific basin that also had a part in the formation. Hawaii is the largest and youngest island in the chain, built from five different volcanoes.

Mauna Loa, covering over half of the Big Island, is the largest shelter volcano on the planet. The measurement from the base starts at the sea floor and to its peak is about 56,000 feet. The climate of Hawaii has played a huge part in the growing of the islands. The islands receive most rainfall from the trade winds on their north and east areas on the islets.

This is a result of orographic rainfall. Coastal areas in general and especially the south and west flanks tend to be drier which caused these islands to be slightly larger. Because of the frequent build-up of Tradewind clouds and potential showers, most tourist areas have been built on the leeward coasts of the islands. In general, the Hawaiian Islands receive most of their precipitation during the winter months. Drier conditions generally prevail from May to September, but the warmer temperatures increase the risk of hurricanes.

Temperatures at sea level generally range from high temperatures of 85-90F (29-32C) during the summer months to low temperatures of 65-70F (18-21C) during the winter months. Very rarely does the temperature rise above 90F (32C) or drop below 60F (16C) at lower elevations.Temperatures are lower at higher altitudes; in fact, the three highest mountains of Mauna Kea, Mauna Loa, and Haleakala sometimes receive snowfall during the winter.

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