Scientists have been somewhat disconcerted by the seismic waves that roam the world, because nobody is quite sure of what caused them.
As reported by National Geographic, these waves were detected on November 11 by sensors around the world. Believing to come from the French island of Mayotte between Madagascar and Africa, they were detected in Zambia and Kenya, then traveled to Canada, Chile, New Zealand and even Hawaii.
Despite waves lasting 20 minutes, no one felt them. Instead, their presence has been spotted on a real-time seismogram of the US Geological Survey. And the scientists were immediately confused as to what was causing them.
"I do not think I have seen anything like it," said Göran Ekström of Columbia University at National Geographic. "That's not to say that in the end, their cause is so exotic."
These waves were considered particularly slow and low frequencies, pulsing every 17 seconds during the event. However, what caused them is a little mysterious – although there are some ideas.
French geological surveyors (BRGM), who are investigating this event, say that this could be the result of a new volcanic activity off the coast of Mayotte. It is also possible that an earthquake triggered the rumblings, or perhaps some kind of rash in the water.
"According to one analysis, this move could be due to the emptying of a nearby magma reservoir, although additional research is needed to verify it," Science Alert noted.
It is interesting to note that six months before this event, scientists had detected a swarm of earthquakes on the east coast of Mayotte, which continued until this last event and caused a very slight displacement of the island. But that does not seem to have the same characteristics as an ordinary earthquake.
"These observations therefore support the hypothesis of a combination of tectonic and volcanic effects explaining a geological phenomenon involving a seismic sequence and a volcanic phenomenon," BRGM said in an article.
Future studies are planned to try to get to the bottom of the event, while scientists continue to explore available seismic data. Of course, it is always possible that this is also an error in detections. We will just have to wait to find out.
[H/T: National Geographic]