A massive underwater volcano about 2,690 feet off the coast of Madagascar is believed to be the result of the largest underwater eruption on record.
(Photo: Getty Images)
In 2018, the volcanic island emerged unexpectedly, stretching from the seabed to the eastern part of the island of Mayotte which lies between the faults of Madagascar and East Africa.
Scientists don’t know much about the processes at work deep within the Earth, but these islands help uncover more information about structure and activity.
The seismic event that gave birth to the new volcano began on May 10, 2018 and within days an earthquake with a magnitude of 5.8 occurred. It rocked nearby islands and scientists then discovered it was the result of new underwater volcanic activity.
Several French government institutions, led by the University of Paris, have embarked on a trip to French African territory in order to deepen their knowledge. They discovered a mountain under the sea that was not there a few weeks ago and they discovered that it took 1.2 cubic miles of lava to form the volcano.
Read also: New sensors help detect and predict volcanic eruptions
A rare phenomenon
Researchers began monitoring the area closely in February 2019 with the use of multibeam sonar, which allowed them to map an area of the seabed of 3,320 square miles.
One action they have taken to help them better understand the nature and origin of the new volcano is to position an array of seismometers on the seabed about three miles deep. Between February and May 2019, their network spotted approximately 17,000 seismic events at a depth of about 30 miles below the ocean floor, which is “very unusual”.
Most earthquakes aren’t as deep as this one, and 84 other events have occurred at extremely low frequencies – another rare occurrence – which has added to the confusion.
The team explained: “The earthquakes have been much deeper than usual in a volcanic context and occur below the limit between the crust and the mantle. They indicate the existence of reservoirs and systems of very deep drainage distributed throughout the lithosphere, which had never before been clearly observed in volcanology.
(Photo: Getty Images)
Swarm of earthquakes
This allowed the researchers to piece together how the volcano formed, and they found it started with a reservoir of magma far below in the molten mantle layer.
Researchers say that below the new volcano, there is a chance that the tectonic processes damaged the rocky outer part of the planet called the lithosphere, which is made of brittle crust and rests on the upper mantle.
This damage caused dykes to empty magma from a reservoir just below the crust, pushing it up through the crust and producing an “earthquake swarm”.
Over time, the material made its way through the seabed and then erupted – at this point, it creates over 1.2 cubic miles of lava to form the new volcano.
Associated article: Earth could be left ‘uninhabitable’ if volcanoes under Antarctic ice erupt
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