Origins of the World’s Largest Single VolcanoHawaii’s Mauna Loa was regarded as the larg

Origins of the World’s Largest Single VolcanoHawaii’s Mauna Loa was regarded as the largest volcano in the Earth until 2013, when William Sager who studied the Tamu Massif for 20 years was able to prove that it was one single volcano. About 1600kms east of Japan in the placid waters of the North-Pacific Ocean is a bump in the ocean floor that is the size of the state of New Mexico/British Isles. This bump is the world’s largest single volcano, the second largest in the solar system (behind Olympus Mons on Mars), and is named Tamu Massif (http://on.fb.me/1R2dma4). This is another significant discovery from surveying our uncharted oceans.So what made this volcano so big? Recently, Sager and his team revisited the Tamu Massif to try and understand its origins, and came up with two hypothesis – the plume head hypothesis and the fertile mantle hypothesis. Firstly, the plume head hypothesis suggests that the Tamu Massif erupted because of a huge plume (giant blob of hot magma) slowly rose from the boundary between the Earth’s core and mantle, erupting at the surface. This theory states that the eruptions were short and fast with the magma spreading out in all directions. On the other hand, the fertile mantle hypothesis suggests that lava was oozing out of cracks and fissures resulting in gradual eruptions with lava that do not go far from the ridges.To test out these theories, Sager and his team set out to map the Massif in more detail to figure out how it got so big. The Tamu Massif was formed 145 million years ago, and it was active for only a few million years. Tamu Massif was formed in the thin parts of the oceanic crust where three long mid-ocean ridges came together into a triple junction. Magnetic analysis of the Massif suggests that part of it formed through steady release of lava along the triple junction, while part of it (central peak) is harder to describe with the data available at the moment. However, a working theory suggests that a large plume of hot mantle rock may have contributed additional heat and material.The recent magnetic field research shows part of the volcano with magnetic stripes with different magnetic properties. This suggests that lava flowed out evenly from the mid-ocean ridges over time and changed in polarity each time the Earth’s magnetic field reversed its direction. However, the central part of the peak is more complicated and its formation is not well understood yet.NateImage Source: John Greene/Schmidt Ocean Institute, http://bit.ly/1I7AIZRSource:http://bit.ly/1YqL0IMhttp://bit.ly/1QEY7Vihttp://bit.ly/1Op070KVideos:http://bit.ly/1YqE26shttp://bit.ly/1S6CZVz -- source link

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