Through the Earth, recorded seismic waves. Nobody knows where they come from

On the morning of November 11, unusual seismic waves were recorded at various places on the planet. The experts can not yet explain their nature, but the source is known: the waters near a small island in the Indian Ocean. About this, says National Geographic.

For the first time, seismic waves were recorded about 24 kilometers off the coast of the island of Mayotte in the Indian Ocean. Oscillations were repeated approximately every 17 seconds for 20 minutes.

After they were registered in Zambia, Kenya and Ethiopia. They crossed the oceans, "hitting" Chile, New Zealand, Canada and Hawaii. As a result, they traveled about 17,000 kilometers.

The waves were weak, no one felt them. An enthusiast, nicknamed matarikipax, noticed the fluctuations on the seismograms in real time and posted screenshots on Twitter. Users began to wonder what had caused them: the fall of a meteorite, the eruption of an underwater volcano or something else?

It is a very strange and unusual seismic signal.
Recorded at Kilima Mbogo, Kenya …# earthquakehttps://t.co/GIHQWSXShd pic.twitter.com/FTSpNVTJ9B

– ******* Pax (@matarikipax) November 11, 2018

"I did not think I had seen anything like it before," said Geran Ekström, a seismologist at Columbia University who specializes in unusual earthquakes.

The peculiarity of the waves is that they appear as coming from nowhere.

Usually, during earthquakes, primary waves or P are first recorded. They rock the rock particles in the direction of the propagation of the wave. After coming secondary, or S-waves. They rock the rock particles perpendicular to the wave propagation direction.

And only then, surface elastic waves (L waves) are released. They usually cause the most severe damage and spread to the surface of the Earth. They resembled the unusual fluctuations that began in Mayotte. With one difference: they were not preceded by primary or secondary waves.

Another special feature: the waves of the Indian Ocean were monochrome. Usually, during earthquakes, oscillations at different frequencies are released. The waves of Mayotte were dominated by a frequency.

Most likely, the waves were related to a series of earthquakes that occurred near Mayotta since May of last year. Meanwhile, hundreds of weak shocks have occurred near the island. True, November 11 – day of mysterious fluctuations – there was no earthquake.

French Geological Survey officials estimate that a new center of volcanic activity could form off Mayotte. From mid-July, the island itself shifted from 6 centimeters to the east and 3 centimeters to the south. Experts believe that a magmatic body of more than one cubic kilometer moves beneath the seafloor. On November 11, French geologists defined the wave as "something new".

Seismologist Geran Ekström has another suggestion. He believes that the mysterious waves were the result of a "slow earthquake" of magnitude about 5 points. Under such an earthquake, the underground energy is not released immediately, but over several hours or even days. Experts plan to continue to monitor the unusual area of ​​activity.