A strange seismic event shook the earth on the 11th of November, and so far, scientists have not been able to explain the phenomenon. The seismic waves started some 31 miles away from the island of Mayotte, situated between Madagascar and the African continent in the Indian ocean. It was picked up by earthquake sensors all over the world, including the ones in Hawaii, 11,000 miles away from the spot. They lasted for about twenty minutes, but no human being felt the impact. The waves were monotonous and in low frequency. The cause of the waves remains unknown, though many are trying to study the occurrence. Columbia University seismologist Göran Ekström told National Geographic that he has never seen anything like it.
One person, Twitter user @matarikipax noticed the signal on the US Geological Survey’s seismograms and posted images of reports from other countries including Kenya, Ethiopia, Spain and New Zealand. This alerted other experts and they started to speculate on the causes and significance of the strange occurrence. Even though the phenomenon was a strange one, Ekström observes, the causes leading to it need not be strange. Seismic activity has been going on in the Mayotte area since the middle of May. The tremors were minor and the largest had the magnitude if 5.8. The activity was on the decline in recent weeks and there were no quakes at the time of the strange event.
Though the area had been volcanic before, no volcano has erupted there for the past 4,000 years. Scientists at the French Geological Survey (BRGM) suggest that the occurrence is caused possibly by a huge magmatic movement under the Indian ocean. (Magma is the molten or semi-molten material found beneath the surface of the earth.) If this is the case, it will explain the changes in the island’s geographical position as well: Mayotte has moved 2.4 inches to the east and 1.2 inches towards the south recently. At present this is only a hypothesis, but further investigations will clarify the matter. The BRGM scientists, along with others, are exploring the possibility now.