HONOLULUHAWAI'I

When the volcano on Oahu was erupting and forming the island, the lava that flowed was heavily composed of Basalt.  Basalt lava is formed only under uniquely high temperatures (2000 degrees farenheit or more).  This high temperature, unique to the Hawaiian hot spot, creates a lava that has a runny consistency and can move at up to 10 kilometers per hour.  This combination tends to form what is refered to as "shield volcanoes".  A shield volcano is one without a dramatic slope, unlike its pacific neighbors along the ring of fire that have much steeper slopes due to a much slower running lava (Glenn 2009).  

The low sloping ridges formed by the Basalt Lava give Oahu the distint valleys and ridges that form the geologic boundary of the City of Honolulu. These ridges and valleys are important becuase of the difference in weather and temperature between the two.  The ridges, which are more exposed to the trade winds experience a more temperate climate, as opposed to the valleys which experience much hotter and less desirable conditions.

The forces that created the island of Oahu are also taking part in its eventual distruction.  As the Pacific Plate moves Oahu off of the underwater buldge created by the  Hawaiian hot spot, this action results in the eventual sinking of the island. Oahu, and its neighboring islands (especially Kuaui) are also very vulnerable to the effects of erosion.  Basalt lava is particulary vulnerable to oxidation through exposure to water and wind.  This oxidation weakens the rock, and eventually allows it to crumble.  The island of Kuaui is losing up to 2400 sq. ft per year from erosion, and geologically soon, so will Oahu (Volcano World).