Seismic ripples were detected 15 miles off the coast of Mayotte, an island between Mozambique and Madagascar in the Indian Ocean in mid November. Some have speculated the strange waves could be related to volcanic activity, but no one really knows.
The waves then travelled through Africa, and crossed oceans to Spain, Chile, New Zealand, Canada, and Hawaii. The waves pulsed for 20 minutes and were not felt by humans. No damages have been reported as a result of the seismic activity.
The event was first noticed by Twitter user @matarikipax who shared a seismogram display from Kilima Mbogo, Kenya, adding, “This is a most odd and unusual seismic signal.”
Speculation about the source of the activity ranges from submarine volcanic eruptions and tectonic earthquakes to an extraterrestrial origin.