Formation of Oahu
Creation of Oahu by Volcanism
Karen Ta: 430
BOT 450
TR 10:30-11:20
Volcanoes are magnificent formations from an opening in a planet’s crust. They form when magma, volcanic ash, and gases escape from a magma chamber below the surface of the planet. Tectonic plates cover the surface of the planet and are constantly moving. Volcanoes are generally found where these plates converge or diverge. Not only are volcanoes found in these areas but also where the Earth’s crust is stretching or thinning. There are volcanoes that form away from plate boundaries in areas that are called “hot-spots”. An example of “hot-spot” volcano formation is the Hawaiian Islands.
Figure 1: (Kreger, 2010) The image above shows that volcanoes are created by hot magma that rises from the Earth’s core and expels through the cracks of the upper mantle and ocean crust. The movement of the Earth’s plates forms these cracks on the surface of the ocean crust.
Every Island is made of one or more volcanoes that have erupted many times and emerged above sea level. A seamount is a mountain that rises above the Ocean floor that is of volcanic origin and does not rise above sea level. Most seamounts are formed from extinct volcanoes that have been eroded and grounded back down by waves. Loihi is an example of an active seamount that is currently being studied because of its assumed Island formation. Because Loihi is located before the Island of Hawaii, it is believed that it will become an Island soon enough. Loihi is slowly moving across the hot spot and growing from its continuous eruptions. By observing the growth of Loihi and the patterns of eruptive activity of older seamounts, geologists can study the growth of the Hawaiian Islands more extensively. (Normark, 1982)
Figure 2: (Rowland) The image above shows a picture of Loihi, a volcanic seamount, that is currently sitting on the hot spot and growing. It is not yet classified as an Island because it is still submerged underwater.
Karen Ta: 430
BOT 450
TR 10:30-11:20
Volcanoes are magnificent formations from an opening in a planet’s crust. They form when magma, volcanic ash, and gases escape from a magma chamber below the surface of the planet. Tectonic plates cover the surface of the planet and are constantly moving. Volcanoes are generally found where these plates converge or diverge. Not only are volcanoes found in these areas but also where the Earth’s crust is stretching or thinning. There are volcanoes that form away from plate boundaries in areas that are called “hot-spots”. An example of “hot-spot” volcano formation is the Hawaiian Islands.
Figure 1: (Kreger, 2010) The image above shows that volcanoes are created by hot magma that rises from the Earth’s core and expels through the cracks of the upper mantle and ocean crust. The movement of the Earth’s plates forms these cracks on the surface of the ocean crust.
Every Island is made of one or more volcanoes that have erupted many times and emerged above sea level. A seamount is a mountain that rises above the Ocean floor that is of volcanic origin and does not rise above sea level. Most seamounts are formed from extinct volcanoes that have been eroded and grounded back down by waves. Loihi is an example of an active seamount that is currently being studied because of its assumed Island formation. Because Loihi is located before the Island of Hawaii, it is believed that it will become an Island soon enough. Loihi is slowly moving across the hot spot and growing from its continuous eruptions. By observing the growth of Loihi and the patterns of eruptive activity of older seamounts, geologists can study the growth of the Hawaiian Islands more extensively. (Normark, 1982)
Figure 2: (Rowland) The image above shows a picture of Loihi, a volcanic seamount, that is currently sitting on the hot spot and growing. It is not yet classified as an Island because it is still submerged underwater.