It’s no surprise to anyone at this point that volcanoes don’t really get pressured when it comes to where they pop up; we do, however, expect events like these to become events of spectacle, accompanied with huge eruptions, earthquakes, and explosions that echo far away.
However, this simply wasn’t the case for this particular volcanic birth—at least, not at first glance; back in 2018, the small French territory of Mayotte, an island off the coast of Madagascar and Mozambique, experienced a total of nearly 11,000 detectable earthquakes. This puzzled scientists interested in the area, since the area had only experienced a grand total of two earthquakes since 1972. Additionally, the last evidence of volcanic activity in the territory was left some 4,000 years ago.
This sent scientists scrambling to figure out just what happened at, or near, the territory that could have registered so many earthquakes in such a short period of time. The results of the findings of one particular team found something spectacular in one of their explorations near the territory: an 820-m (2,690-ft) tall underwater volcano that wasn’t really there before. Their findings were published in the journal Nature Geoscience.
Paris Institute of Earth Physics (IPGP) marine geoscientist Nathalie Feuillet served as lead researcher of the team, some members of which then proceeded to do some onsite study by boarding the maritime research vessel Marion Dufresne.
Feuillet and team found that the earthquakes detected by their equipment were localized not too far off the coast of Mayotte—in fact, it was only some 10 km (6 mi) east of the island. What’s striking to them, however, is its depth; the source of the earthquakes was somewhere between 20 and 50 km (12 to 31 mi) deep.
To truly find what caused the earthquakes under the waves, the team resorted to seeking the help of the multibeam echo sounder instrument onboard the research vessel. The device can “ping” the seafloor using soundwaves to map it—which revealed the true culprit behind it all: an underwater volcano shaped like a pyramid.
What’s striking to Feuillet and the team, however, is the fact that an earlier survey of the underwater area back in 2014 showed no such volcano in this location. To them, this meant that the volcano was new—likely very new, given the earthquakes that sounded its gradual arrival. The seafloor also originally measured out at around a roughly-uniform 3,300 m (10,827 ft) below sea level all throughout—and that the new volcano in the area measured out at around 2580 m (8,465 ft) below sea level at its peak by May of 2019.
Further analysis of the volcano revealed that its magma runs deep. “The source of the magma, the reservoir, is very deep [at 55 km (34 mi) underground]. […] This is the first time in volcanology that we can see such a deep reservoir at the base of the lithosphere,” Feuillet told the website Live Science in communications. This means that this new volcano sources its magma from the deepest-known reservoir known to scientists at the time of writing.
It also appears that the volcano isn’t necessarily done with its show, and is still erupting. Feuillet noted that the last-recorded lava flow underwater was only back in January 2021. Thus, Feuillet and team are constantly monitoring the new volcano for its earthquakes and volcanic activity.
(For more news on volcanoes, check out how their “super” versions remain active for far longer than what scientists once thought. After that, read up on how volcanic activity may have helped usher dinosaurs into the global spotlight, setting the stage for their domination on Earth that would last for hundreds of millions of years.)
References
- Feuillet, N., Jorry, S., Crawford, W. C., Deplus, C., Thinon, I., Jacques, E., Saurel, J. M., Lemoine, A., Paquet, F., Satriano, C., Aiken, C., Foix, O., Kowalski, P., Laurent, A., Rinnert, E., Cathalot, C., Donval, J.-P., Guyader, V., Gaillot, A., … Van der Woerd, J. (2021). Birth of a large volcanic edifice offshore Mayotte via lithosphere-scale dyke intrusion. Nature Geoscience, 14(10), 787–795. https://doi.org/10.1038/s41561-021-00809-x
- Geggel, L. (2021, October 20). World’s biggest underwater eruption birthed skyscraper-size volcano. Live Science. https://www.livescience.com/largest-underwater-volcanic-eruption-on-record
- Starr, M. (2021, September 30). Largest underwater eruption ever recorded gives birth to massive new volcano. ScienceAlert. https://www.sciencealert.com/the-largest-underwater-volcanic-eruption-ever-recorded-gave-birth-to-a-new-volcano
