Monday, February 13, 2012

Island beginnings

Maui exemplifies many of the geographic features we've talked about so far, beginning with the actual formation of the island. Maui, like all the Hawaiian islands, was formed as a result of a volcano. Haleakala (dormant since 1790) (1) was produced by the Hawaiian hotspot. Because Hawaii is not located on the boundary between tectonic plates, the hotspot is particularly unique. As magma located close to the sea floor rises through a conduit, it cools and layers, resulting in an island. While the hot spot remains stationary, the plate above it moves, resulting in a chain of islands that were carried off the hotspot by top-layer drift. (2)



(4)

Currently the hot spot is facilitating the activity of Kilauea on/under the Big Island, some 113 miles away from Maui's current location.

As the second oldest of the islands it is smaller than the Big Island due to longer drift and therefore longer exposure to erosion and weathering. In addition to mere drift erosion, volcanic activity around the Pacific rim results often in earthquakes and tsunamis, such as the Tsunami that hit South East Asia after Christmas of 2004. Presently Maui is not as susceptible to tsunamis as it once was due to protection from outlying minor islands, however historically Maui had no defense, particularly at the island's creation 1.1 million years ago. (3)



As an extrusive formation Haleakala is a typical shield volcano composing the majority of the island. The particularly fluid magma that resulted from its eruptions traveled farther before cooling, creating a mound that is particularly wide but not necessarily steep (12,000ft elv, 30,183 acres). Basalt, the foundation of the island, is the most common rock type outside the main continents and is rich in oxidized minerals. The mineral grain in basalt is so fine that it cannot be seen by the naked eye, however it is highly porous due to escaping gas as it reaches the surface and cools.