The largest-ever documented active submarine eruption forms a massive new volcano
The largest-ever documented active submarine/underwater eruption has formed a massive new volcano off the eastern coast of the island of Mayotte.
The new volcanic feature is thought to be part of tectonic structures between the East African and Madagascar fissures. The new underwater volcano has been formed as a result of the May 2018 seismic event that was felt across the entire globe.
The underwater feature is helping scientists understand deep Earth processes with little known about them. The volcano formed rises 820 meters (2,690 feet) from the seafloor and had never existed prior to the earthquake that rocked the island in May 2018.
“This is the largest active submarine eruption ever documented,” the researchers wrote on a paper published in Nature Geoscience.
“The volumes and flux of emitted lava during the Mayotte magmatic event are comparable to those observed during eruptions at Earth’s largest hotspots,” the researchers said.
The seismic reverberations started on 10 May 2018 a few days later, a magnitude 5.8 quake struck, rocking the nearby island.
The signals pointed to a location around 50 kilometers from the East coast of Mayotte, a French territory and part of the volcanic Comoros archipelago sandwiched between the Eastern coast of Africa and the Northern tip of Madagascar.
The French research team, led by geophysicist Nathalie Feuillet of the University of Paris in France, was sent to investigate the volcanic event and found there was an undersea mountain that hadn’t been there before.
The team detected 17,000 seismic events, from a depth of around 20 to 50 kilometers below the ocean floor – a highly unusual finding, since most earthquakes are much shallower.
An additional 84 incidents were also highly unusual, detected at very low frequencies.
The researchers were able to figure out how the formation of the new volcano occurred using the data.
According to their findings, it started with a magma reservoir deep in the asthenosphere (the molten mantle layer located directly below Earth’s lithosphere).
The tectonic processes caused damage to the lithosphere, resulting in dykes that drained magma from a reservoir up through the crust, producing multitudes of earthquakes.
The material made its way to the seafloor, where it erupted, producing 5 cubic kilometers of lava and building the new volcano.
The new volcanic feature is between 30 and 1,000 times larger than any other deep-sea eruption. This makes it the most significant undersea volcanic eruption ever recorded.