A major seismic event that began in May 2018 and was felt worldwide has led to the birth of a new underwater volcano.
Off the east coast of Mayotte, the giant new feature rises 820 meters (2,690 ft) from the seabed, a landmark that did not exist before the earthquake that rocked the island in May 2018.
“This is the largest active volcanic eruption ever documented,” The researchers wrote in their paper.
The new feature, thought to be part of the tectonic structure between the East African and Madagascar faults, is helping scientists understand processes inside Earth that we know relatively little about.
Seismic tremors from the ongoing event began on May 10, 2018. Just days later, on May 15, a magnitude 5.8 earthquake rocked the neighboring island. At first, scientists were confused. But it didn’t take long for a volcanic event to occur, which had never been seen before.
Signs point to the site some 50 kilometers off the east coast of the island of Mayotte, a French territory and part of a volcano. Comoros Islands It is located between the east coast of Africa and the northern tip of Madagascar.
So a number of French government agencies sent a research team to verify this; There, for sure, was a mountain under the sea like never before.
Led by geophysicist Nathalie Foyer of the University of Paris in France, the scientists describe their findings in a new research paper.
The team began observing the area in February 2019. They used multi-beam sonar to map an area of 8,600 square kilometers of seafloor. They also placed a network of seismographs on the seabed as deep as 3.5 kilometers, and combined them with seismic data from the island of Mayotte.
Between February 25 and May 6 2019, this network detected 17,000 seismic events, from depths of 20 to 50 kilometers below the seabed – a very unusual finding, as most earthquakes are very shallow. The additional 84 events were also very unusual, detected at a very low frequency.
Armed with this data, the researchers were able to reconstruct how the formation of the new volcano occurred. It begins, according to their findings, with a magma reservoir in the depths of the asthenosphere, the layer of molten mantle that lies directly beneath Earth’s lithosphere.
Kronologis letusan. (Feuillet et al., Nature Geoscience, 2021)
Beneath the new volcano, tectonic processes may have caused damage to the lithosphere, creating a dam that drained magma from the reservoir through the crust, generating a swarm of earthquakes in the process. Eventually, this material reaches the ocean floor, where it erupts, producing 5 cubic kilometers of lava and building a new volcano.
The low-frequency events likely result from shallow fluid-filled voids in the crust that will be repeatedly stimulated by seismic stress on faults close to the cavity.
In May 2019, the volume of new volcanic edifice extruded was between 30 and 1,000 times greater than would be expected for another deep-sea volcanic eruption, making it the most significant underwater volcanic eruption ever recorded.
“The volume and flow of lava released during the Mayotte magmatic event is comparable to that observed during eruptions at Earth’s largest hotspots,” Researchers write.
“Future scenarios could include a new caldera collapse, an upslope eruption or a coastal eruption. The massive lava flows and cones on the Mayotte upper slopes and coast suggest that this has happened in the past.”
“Since the discovery of new volcanic structures, an observatory has been established to monitor activity in real time, and return flights continue to follow the evolution of eruptions and structures.”
Search published in natural earth science.
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