[Rockhounds] Geologists Discover Largest Underwater Volcano, Explain Weird Hum Heard Around the World

[Kreigh Tomaszewski]

A strange seismic event off the coast of Africa has led scientists to a
mighty finding: the discovery of the largest underwater volcanic eruption
ever recorded.

The eruption also may explain a weird seismic event recorded in November
2018 just off the island of Mayotte, located between Madagascar and
Mozambique in the Indian Ocean. Researchers described that event as a
seismic hum that circled the world, but no one could figure out what
sparked it.
https://www.livescience.com/65545-largest-underwater-volcano-seismic-hum.html