On the morning of November 11, shortly before 9:30 UT, a mysterious seismic rumble swept across the world. Seismic waves emanated from a point about 15 miles off the coast of Mayotte, a French island sandwiched between Africa and the northern tip of Madagascar.
The first incomprehensible lithospheric waves were registered by seismographs in Africa - sensors located in Zambia, Kenya and Ethiopia. But waves continued to spread across continents and oceans until they were recorded in Chile, New Zealand, Canada, and even Hawaii - more than 11,000 miles away!
The waves made the Earth buzz like a bell, however, despite the fact that they lasted for 20 minutes, no one practically noticed them, since people did not feel these waves.
The event became known to geologists solely thanks to the work of the attentive enthusiast @matarikipax, who first saw them on the seismic sensors and posted a message on Twitter. And when geologists from all over the world turned to the readings of seismometers, what they saw put them all to a standstill.
“I've never seen anything like it in my life,” admits Geran Ekström, a professor of seismology at Columbia University who specializes in unusual earthquakes.
So what has put the global geological community at a standstill? The fact is that, as Stephen Hicks, a seismologist at the University of Southampton, explains, during a normal earthquake, the increase in tension in the earth's crust occurs in a shock lasting only a second. This event sends out a series of waves known as the "wave train".
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The fastest signals are primary waves, or P-waves, which are compression waves traveling through the lithosphere. Then there are secondary waves, or S-waves, which move in the direction perpendicular to the wave. And only after that, slow, long-period, low-frequency surface waves come, which appeared in Mayotte and made the arrows of seismographs all over the world dance. But the problem is that there was NO EARTHQUAKE in Mayotte. That is, there was no shock, no subsequent P and S waves. Slow waves of tremendous force came as if from nowhere.
However, what even more surprised all world seismologists - these strange waves were as if very correct mathematically, as if some artificial object caused vibrations in the mantle, where waves of the correct period and size appeared. But at the disposal of mankind there are no such huge objects that could cause waves of such force.
What was it then? A spontaneous meteorite strike? Eruption of an underwater supervolcano? Cthulhu awakened from sleep and now rises from the depths? Seismologists even put forward such versions, since no theories can answer the question posed by seismographs.
In addition, the problem is that, unlike the territory of the United States, for example, in the Mayotte region there are practically no modern sensors and no one knows what is happening on the ocean floor.
According to recent work by the French Geological Survey (BRGM), which has long been observing a seismic swarm in the vicinity of Mayotte, we are most likely talking about the birth of a new island, which is currently an underwater volcano.
Geran Ekström, professor of seismology at Columbia University, suggests that this unusually clear seismic signal could have been caused by magma squeezing through an existing crevice in the subsurface. However, he is not sure of this.
Helen Robinson, an applied volcanologist at the University of Glasgow, fully agrees with Ekström: “Such elastic waves are absolutely characteristic of magma injecting itself through the rock. But the problem is that these waves are too good, too perfect, to be natural. Maybe it's Cthulhu,”Helen jokes, but shrugs.
The fact is that no drilling operations take place off the coast of Mayotte. Moreover, even if such works were traced to create a wave that would be recorded by seismographs on Gaia, the diameter of the drill should have been several kilometers. So for now, geologists do not know anything about the source of these signals, and BRGM plans to send either a bathyscaphe or a special research boat to the place of an underwater volcano.