11 November 2018 Mayotte seismic event

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The 11 November 2018 Mayotte seismic event is a seismic event of unknown origin that occurred about 24 kilometres (15 mi) off the coast of Mayotte, an overseas department and region of France in the Indian Ocean. It was recorded by seismograms in many countries, including Kenya, Chile, New Zealand, Canada, and Hawaii, almost 18,000 kilometres (11,000 mi) away.[1] Despite this, no one felt it. The seismic waves lasted for over 20 minutes.[2] Most earthquakes have P-waves and S-waves, which are later followed by long-period surface waves. The Mayotte event lacked P-waves and S-waves, but did cause a long-period surface wave[3][4] travelling at 14,000 km/h (9,000 mph) around the globe.[1] Additionally, the signal released by the earthquake was a clean "zigzag," while most earthquake waves have multiple frequencies.[2]

Cause[edit]

The cause of the event was initially unknown,[5][4] but scientists from the French Geological Survey believe it may have been caused by an underwater volcano, and also related to an earthquake swarm nearby.[2] The island of Mayotte had experienced hundreds of tremors since May 2018, including a magnitude 5.8 earthquake on 15 May. The quakes had been tapering off until the event occurred.[3]

Another possible explanation that was suggesed was that magma from a volcanic chamber approximately 16 km (10 mi) miles underneath the seafloor near Mayotte had suddenly drained which could have led to the roof of the chamber to collapse causing the vibrations.[6]

In May 2019, an 800 meter high undersea volcano was found that wasn't there before. This volcano is now assumed to have been the cause of the tremors.[7]

References[edit]

  1. ^ a b Trevor Nace (3 December 2018). "Strange Waves Rippled Across Earth And Only One Person Spotted Them". Forbes. Retrieved 26 January 2019.
  2. ^ a b c Maya Wei-Haas (28 November 2018). "Strange waves rippled around the world, and nobody knows why". National Geographic. Retrieved 30 November 2018.
  3. ^ a b Robber Berman (29 November 2018). "An unexplained seismic event 'rang' across the Earth in November". The Big Think Inc. Retrieved 26 January 2019.
  4. ^ a b "Strange seismic waves were picked up circling the globe on November 11. Now seismologists are trying to figure out why". News Limited. 29 November 2018. Retrieved 26 January 2019.
  5. ^ Lucia Peters (29 November 2018). "Unusual Seismic Waves Shook The Earth On Nov. 11 & Scientists Still Don't Completely Know Why". Bustle Digital Group. Retrieved 26 January 2019.
  6. ^ "'Magma shift' may have caused mysterious seismic wave event". The Guardian. 2018. Retrieved 26 January 2019.
  7. ^ Roland Pease (21 May 2019). "Ship spies largest underwater eruption ever". Science. Retrieved 22 May 2019.