Back on November 11, 2018, a planetwide rumble emanated from somewhere between eastern Africa and Madagascar. This strange signal, thought by scientists at the time to be related to a colossal but hard-to-identify magmatic process, was pinpointed to have come from 30 miles east of the island of Mayotte, beneath the waves.
It quickly became apparent that this low-frequency tremor took place in the midst of a complex sequence of other, more “ordinary” seismic shakes. This caught the attention of the French government that administers the isle, which was already keeping an eye on what was going on. Now, after some geological detective work, they know what’s been causing at least some of these quakes: the world’s newest volcano.