Seismic sensors first caught the originating event nearby island between Madagascar and Africa. Then, the alarm bells started calling away like Chile, New Zealand and Canada.
Hawaii, almost exactly on the other side of the planet, also handed the "event".
Nobody knows x & # 39; was.
Meteorite? Submarine Volcano? The nuclear test?
"I do not think I have seen anything like it," the National Geographic reports say that seismologu of Columbia University Göran Ekström. "This does not mean, in the end, their case is exotic."
In the center of the mystery is the tiny island & # 39; Mayotte, placed about halfway between Africa and Madigascar. Was subject to a swarm of & # 39; earthquakes since May. Most of them were minor, but the largest – 8 & # 39; May – were the biggest in recorded history of the island, topping Magnitude 5.8.
But the blow of the earthquake was decreasing before found earlier this month mysterious blockage.
Ekström, who specializes in unusual earthquakes, indicates a lot about the event & # 39; November 11 was weird. It was as if the plant sits like a bell, and kept a monotonous & # 39; low frequency as spreads.
Earthquakes, by their very nature, usually register as "crack" short. As tensions in the Earth's crust in & # 39; suddenly release, pulses of & # 39; seismic waves may be identified by & # 39; clearly run & # 39; outside where crushing occurs.
The first sign is called primary wave: compression waves & # 39; frequency surrounding f & # 39; bunches.
Then comes a secondary wave: these waves & # 39; frequency tend to "wiggle" a little more.
Only then is the surface waves: these slowly rumbles, deep tend to last, and can surround the Earth several times.
The 11 event & # 39; November is marked by missing primary or secondary waves.
All that was registered was the wave of tread depth and resonance. And with "sounds" as the waves of the earthquake tends to surface. Instead, it kept much cleaner frequency – almost musical -.
National Geographic reports state that the French Geological Survey suspect that a new volcano can & # 39; develop off the coast of & # 39; Mayotte. While the island was created by & # 39; volcanic activity, has been in the eye for more than 4000 years.
The French believe that weird ringing can & # 39; has been generated by movement & # 39; Magma some 50km & # 39; the offshore and deep under water. This is supported by GPS sensors to identify Mayotte to move around 5cm in Southeast & # 39; less than five months.
But he badly placed region. Exactly what is under the ocean can & # 39; only be guessed at.
Ekström believes that non-pure usual signal can & # 39; caused by magma sloshing around inside a room, or be forced by a gap in the rock & # 39; below the surface.
But he is not sure.