Geoscientists were wrong on the "biggest volcano in the world"

In 2013, Tamu Massif – a giant submarine volcano off the coast of Japan – stole the Hawaii crown as the world's largest volcano. But it's not a real volcano at all.

The researchers published an article in 2013 in the journal Nature Geoscience, concluding that Tamu Massif was a giant "shield volcano", even bigger than the Mauna Loa in Hawaii, which stands at 9,500 meters from the bottom of the island. Ocean and covers thousands of kilometers old and solidified magma flows. Now, in a new article, the researchers conclude that the 2013 article was fake and that Tamu Massif is not a shield volcano. The crown, according to this new research, returns to Mauna Loa.

Shield volcanoes form when only one volcanic plume spills enough lava over time, and that lava spreads far enough to form a bulging mountain around the opening of the volcano. Mauna Loa is a shield volcano. The same goes for most of the much smaller volcanoes of Iceland. (Cone-shaped volcanoes, such as Mount St. Helens, are not shields, but "stratovolcans".) In 2013, researchers thought that Tamu Massif was formed in the same way. But the new document suggests that they are wrong. [5 Colossal Cones: Biggest Volcanoes on Earth]

Tamu Massif is a shallow volcanic system, with gently sloping sides; it extends about 650 km wide and 4 km high. The huge submarine volcano lies along a part of the mid-oceanic backbone system, the series of boundaries that surrounds the world between different tectonic plates. This huge system is somehow the largest volcano in the world, because the magma can swell upward and spread as lava on the entire surface of the crust. But this volcanism does not look like volcanism that forms a shield volcano.

Although Tamu Massif is sitting along the ridge, the researchers thought that it had formed when a plume of magma had burst from its center and had elapsed under it. form of lava to cool. That's why they claimed in 2013 that it was a single shielded volcano. The researchers now think that this is formed when, as part of the ongoing volcanism on the dorsal, the magma has pioneered into the crust, causing the swelling and swelling of materials already on the seabed.

The proof is magnetic anomalies – the magnetic field lines detected by the researchers in the Tamu Massif follow the arrangement of the other field lines of the ridge, not the magnetism you expect from a shield volcano.

This means that rather than being a single self-generated volcano placed along the ridge, the Tamu Massif is only one element of the ridge system, which forms sub-mountains. marines all over the world. Mauna Loa reigns supreme.

The document documenting this work was published on July 8 in Nature Geoscience.

Originally published on Science live.