Source: Waking Times

Date: December 1, 2018

By: Emma Fiala

Something very unusual rumbled across planet Earth on November 11th, and scientists say they’ve never seen anything like it. For 20 minutes, instruments measured unusual seismic activity over 10,000 miles away from where it originated, yet not a single human felt them.

Seismic waves, originating from the French island of Mayotte, between Africa and Madagascar, traveled around the world. They were recorded throughout Africa and as far away as Chile, New Zealand, Canada and Hawaii, nearly 11,000 miles away.

Not only did no humans feel these bizarre seismic waves, only one human noticed the strange signal on the United States Geological Survey’s (USGS) seismograph displays:

Matarikipax also tweeted waves detected in Zambia, Ethiopia, Spain and New Zealand. Thanks to this social media savvy earthquake enthusiast, researchers around the world took note.

The French Geological Survey team (BRGM) working at the Geology Laboratory of the Ecole Normale Supérieure in Paris, reported that on November 11th “an atypical very low frequency signal was detected by the international networks.” Low frequency signals of this kind are characteristic of volcanic phenomena.

Göran Ekström, Columbia University seismologist, told National Geographic:

“I don’t think I’ve seen anything like it.”

Normally, an earthquake releases its energy in one big burst, resulting in the presence of three different waves – P-waves, S-waves, and surface waves. Typical P- or S- wave was recorded during the event.

The first type is a compressional wave (P-wave). These waves are the fastest of the three and they shake the ground back and forth. The next is a shear wave (S-wave). S-waves translate into large jolts and strong side-to-side shaking. Both P-waves and S-waves have high frequencies.

The third type is a surface wave. Surface waves occur near the earth’s surface and are felt as a rolling motion. Strong earthquakes can result in surface waves that travel the globe multiple times.

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