On November 11, 2018 there was a strange rumble that echoed through the entire planet (see it here if you missed it - Strange Seismic Waves Picked up Circling the Earth on November 11, Seismologists Stumped) and was picked up by seismic instruments all over the world leaving scientist baffled for the moment. It is now being claimed that they have discovered the source... via sputniknews: The seismic signal which initially puzzled scientists was apparently a product of undersea volcanic activity, such as the inflation or deflation of calderas or simply the movement of magma below the sea floor. A dedicated seismologist has apparently managed to uncover the nature of strange seismic event that recently occurred in the vicinity of Mayotte, a French island situated between mainland Africa and Madagascar in the Mozambique Channel Earlier in November, scientists were left baffled by the discovery of low-frequency tremor which sent "seismic rumblings around the surface of much of the planet."