How was Hawaii Formed?


Image: Surveying in Hawaii

 

Hawaii’s tropical coral reefs are offering us a chance to capture and study reefs which are very different to others we have surveyed around the globe.  Hawaii and its volcanoes, that have provided a habitat for corals, reef life and more recently humans, are awe inspiring and truly worthy of myth creating.

 

 

The Legend of Maui

 

According to the rich Hawaiian culture and legend, Hawaii was formed by a trick one boy played on his older brothers. Maui (where the team are based at present) was a cheeky young boy with a short attention span, this made Maui a poor fisherman and lead to his older brothers teasing him about his inability to catch fish.

 

One day Maui came into possession of a great magical fishing hook called Manaiakalani that could catch anything. With his new hook in hand, Maui and his brothers went fishing and Maui cast his magical hook into the deep in an effort to catch the biggest fish, the hook though latches on to the sea floor. Maui tells his brothers that he has hooked the biggest fish and orders his brothers to row as hard as they can. The brothers, feeling the drag of the catch, put all their effort into rowing and pulling up the supposed massive fish that Maui has hooked and do not notice that they are pulling up the sea floor and creating the islands of Hawaii.

 

 

The Hot Spot

 

Geologists have another explanation to the forming of Hawaii. Geologists believe that the chain of islands that form Hawaii were created by a “hot spot” in the middle of the Pacific tectonic plate, where magma rises up and erupts through the tectonic plate and out onto the sea floor. This hot spot is located in a fixed position while the Pacific tectonic plate inches slowly northwest towards the Marianas Trench.

 

Different volcanoes are made up of different forms of magma that help shape the volcanoes. The Hawaiian volcanoes are made of basalt magma, which has a high fluidity and the ability to form lava flows. The fluidity of the molten basalt means that the Hawaiian volcanoes and islands form gentle sloping sides up to their craters. By comparison, volcanoes that are formed by magma with a high silica content are more viscous, or have lower fluidity. These silica volcanoes can grow up with higher internal pressure leading to steeper sides of the volcano and produce greater explosive eruptions.

 

 

Creating new islands

 

The Islands can be dated by their distance from the hot spot that is currently still building the island of Hawaii. The oldest land form in Hawaii is 28 million years, with the youngest, the Island of Hawaii or Big Island, approximately 400,000 years old. The next island is already being formed, Lo’ihi is presently 975 metres below the sea surface and is expected to break the surface sometime in the next 10,000 to 100,000 years, get your cameras ready.

 

The island of Hawaii is largest single structure on earth, coming up from the sea floor from 6,000m and rising 4,207m above sea level, to put that in perspective Australia’s tallest mountain, Mt Kosciuszko is 2,228m above sea level and our last scientific expedition in the Maldives is about 2.4m above sea level!

 

 

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