The largest underwater eruption ever recorded has produced a massive new underwater volcano near the French island of Mayotte in the Indian Ocean.
French scientists recently discovered the new feature rising on the ocean floor between Africa and Madagascar. The volcano, according to their assessment, is about 800 meters high and 5 kilometers across.
"This thing was built from zero in 6 months," said Marc Chaussidon, the director of the Institute of Geophysics in Paris, in a story published by Science.
Finding A Newborn Volcano Under The Ocean
According to scientists, since the middle of last year, the island of Mayotte, a part of the Comoros archipelago, has been experiencing small earthquakes almost every day. To investigate, last February, scientists placed six seismometers at the bottom of the ocean close to the activity.
The team finally retrieved the seismometers earlier this month. They released initial results last week.
The seismometers reported a tightly clustered region of earthquake activity from 20 to 50 kilometers deep in the crust. GPS measurements of Mayotte, meanwhile, revealed that the island has sunk by about 13 centimeters and moved 10 centimeters to the east in the past year, suggesting a shrinking magma chamber.
A survey of the seafloor using a multibeam sonar showed that as much as 5 cubic kilometers of magma have erupted into the sea floor. They also detected plumes of bubble-rich water coming from the center and flanks of the volcano.
The scientists noted that fishermen have reported shoals of dead fish. The team collected water samples from the plumes and dredged up rocks from the flanks of the volcano for analysis.
A Hum Spreads Around The World
The Comoro archipelago is not a stranger to volcanic activity. Mount Karthala, located at the west end of the island chain, last erupted in 2007. However, the volcano nearest to Mayotte has been inactive for 7,000 years.
Since May last year, more than 1,800 earthquakes greater than magnitude 3.5 has been recorded in Mayotte, according to the National Geographic. Then, in November, low-frequency rumbles spread around the world, lasting for more than 20 minutes.
The researchers are yet to publish a peer-reviewed study of the events. Many questions about the curious phenomenon remain unanswered, including how old exactly the underwater volcano is. It did not show up in the previous seafloor map drawn up in 2015. The team believes that it did not exist before the earthquake activities in Mayotte started in May 2018.
It is also unclear how the volcano is related to the low-frequency signal detected in November.
Nathalie Feuillet, the leader of the scientific expedition that investigated the submarine volcano, is reserving judgment until she and her team have carried out a complete analysis. They hope to extend their mission by an additional several months to continue to monitor the newly formed underwater volcano.