Seismic sensors first picked up the event originating near an island between Madagascar and Africa. Then, alarm bells started ringing as far away as Chile, New Zealand and Canada.
The event that seismologists recorded on 11/11/2018 was unusual in many ways. To begin with, two of the three main waveforms that always accompany earthquakes were noticeably absent. Second, this event also lacked the short, sharp cracks that are common in most all earthquakes. But the thing that is puzzling scientists the most is that, instead of the low rumble you get with earthquakes, this event produced an even, low-frequency musical sound [READ MORE HERE]