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The researchers used remote-controlled vehicles to explore the deep waters of the Marianas Trench. Image via Oregon State University.
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A team of researchers has documented a recent volcanic eruption in the western Pacific Ocean about 4.5 km from the surface of the ocean, which it describes as the deepest known eruption on Earth, deeper than Mount Rainier.
According to the researchers, the eruption would probably have occurred between 2013 and 2015 in the background of the Mariana Islands, an area of the seabed with active volcanoes in the Marianas trench of the Pacific Ocean. The Mariana Trench is the deepest part of the Earth's oceans and the deepest part of the Earth itself. It is located just east of the 14 Mariana Islands, near Japan. It was created by ocean-to-ocean subduction, a phenomenon in which a tectonic plate surmounted by an oceanic crust is subducted under another plate also surmounted by an oceanic crust.
Location of the Mariana Trench. Image via Wikipedia.
Bill Chadwick is a marine geologist at Oregon State University and lead author of the study, published Oct. 23, 2018 in a peer-reviewed journal. Frontiers in Earth Science. Chadwick said in a statement:
We know that most of the volcanic activity in the world takes place in the ocean, but remains largely invisible and undetected. This is because underwater tremors associated with volcanism are generally weak and most instruments are far from the earth.
Many of these areas are deep and leave no clue to the surface. This makes the underwater eruptions very elusive.
The Mariana back-arch eruption was first discovered in December 2015 by on-board cameras aboard an autonomous underwater vehicle. The photos revealed the presence of a dark, glassy immaculate lava flow on the seabed with no sediment cover. Ventilation of the hydrothermal ventilation fluid indicated that the lava flow was still hot, and therefore very young.
Fresh lava from the bottom of the sea. Image via Oregon State University.
The data indicated that there had been significant changes in depth in the area between the 2013 and 2015 surveys, the researchers said, which corresponds to an eruption. The new lava flow extended over an area about 7.2 km long and was between 40 and 137 meters thick.
Scientists returned in April and December 2016 and used two remotely operated vehicles to explore the site. New observations showed a rapidly declining hydrothermal system on the lava flows, suggesting that the eruption had occurred only a few months before its discovery the previous year. Chadwick said:
Generally, after an eruption, heat is released and evacuated for a few years and organisms colonize the vents, creating a new ecosystem. But after a while, the system cools and the mobile organisms go away. There was always a breakdown, but it had obviously dropped a lot.
In conclusion: an underwater volcanic eruption discovered in the Mariana Trench of the Pacific Ocean is the deepest possible.
Source: A recent volcanic eruption discovered in the center of the Central Mariana Islands backbone
Via Oregon State University
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