When a Full Moon coincides with its closest approach to Earth, it is called a Super Full Moon. There is a clear view of the moon, appearing 14 per cent bigger and up to 30 per cent brighter than usual. Last November 14, people from across the globe waited until nightfall to view the stunning ‘Supermoon’, which was set to the closest it has been to Earth since January 26, 1948.
A powerful 7.8 magnitude earthquake hit the South Island of New Zealand early morning of November 14 triggering hundreds of aftershocks. People had to wonder if there was a connection between the ‘supermoon’ and this mega-earthquake. In the Philippines Lady Caycay earthquake, magnitude 8.2 in Panay Island, occurred on January 25, 1948, one day prior the Supermoon, 68 years ago.
According to a study published in Nature Geoscience in September this year, a seismologist at the University of Tokyo and his colleagues investigated on large earthquakes – magnitude 5.5 or greater – around the world over the last two decades. His team reconstructed the strength of gravitational pull, known as “tidal stress,” in the two weeks prior to each tremor.
They found no clear correlation with smaller quakes, but many of the largest earthquakes like the quake in Sumatra in December 2004, the 2010 temblor in Chile, the magnitude-9.0 quake on March 11, 2011 in Japan occurred during periods when the pull of the moon and sun were particularly forceful (during full and new moon, the two times each month when tidal stresses are highest).
Statistically significant correlations between seismicity and tidal stress have been discovered using large data sets, but the correlations are generally limited to special regions or circumstances. Better understanding of this mechanism could help predict when known faults are more likely to produce killer quakes, the researchers said.
(Floro Mercene)