Researchers find gigantic volcano in the Pacific - Spiegel Online

from Tamu Massif has hardly anyone heard. Deep below the sea surface is the volcano in the Northwest Pacific east of Japan. But a new study in the journal “Nature Geoscience” now shows how gigantic the single volcano really is: Its dimensions were similar to those of Olympus Mons on Mars, the largest known volcano in the solar system. The well is 20 km though significantly higher than the Tamu Massif, takes to the researchers but only about 25 percent more volume one.

around 145 million year old formation is situated on the south-end of the Shatsky Rise plateau, whose size is about that of Japan. Many geologists believe that such plateaus – large, flat areas of the ocean floor that rise well above the surrounding terrain – back to massive eruptions

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far has been assumed that each of the outbreaks occurred in several places, so the rocks are massive volcanic chains, write study author William Sager of the University of Houston (Texas, USA) and his colleagues. But unlike some in the Hawaiian shield volcano chain there had been at Tamu Massif apparently mainly eruptions at a single site. It thus handle is probably a single volcano 650 kilometers long and 450 kilometers wide.

It differs also from tens of thousands of other underwater surveys at the bottom of the oceans. Because of the immensity, the flanks of the volcano fell off very gently. You could walk on them, Sager, it would probably be difficult to distinguish uphill and downhill. The average slope of the terrain lies at about one degree.

inactive after a few million years

Scientists rock samples were analyzed at Tamu Massif. These were collected in 2009 as part of the Integrated Ocean Drilling Program onboard the drillship “Joides Resolution”. It was found that the basalts found all come from a single source near the center. However, scientists drilled cores of up to 175 meters in length – and solid measures seen from the ocean floor up to four kilometers

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So the researchers also evaluated seismic data that had the research vessel “Marcus G. Langseth,” recorded in 2010 and 2012. The pictures look amazing, and the undersea volcano is easy to recognize, even for laymen. Thus, the shield-shaped undersea mountain could be formed when the immense Lavamengen leaked during cooling and created the flat, far-reaching connections. A few million years later, the volcano is extinct.

Perhaps there is on earth even larger volcanoes on the seabed. Interesting possibility could be to Ontong Java Plateau be. This is also in the Pacific, north of the archipelago of the Solomon Islands. Here, however, the researchers still do not know whether it possibly originated about 120 million years only by a volcano – or whether numerous magma vents for the formation of the plateau ensured

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