Gravitational tug of Moon could trigger quakes

Submitted by Natalia Hall on Wed, 09/14/2016 - 13:20




The moon has been rotating around our planet for four and a half billion years. The slight tug of the moon’s gravity helps keep Earth steady on its axis and leads to the generation of fluctuation in ocean tides. But, there are times when the slight pull changes into a bit too much.

A study, published in Nature Geoscience this week, suggested that the same gravitational influence the moon has on our oceans could also prompt earthquakes along the most fragile faults of Earth.

The University of Tokyo researchers measured the levels of ‘tidal stress’ prior to huge earthquakes of the last some decades and discovered that high stress levels were often followed by massive earthquakes.

The scientists wrote, “This suggests that the probability of a tiny rock failure expanding to a gigantic rupture increases with increasing tidal stress levels. We conclude that large earthquakes are more probable during periods of high tidal stress”.

The scientists mentioned that the December 2004 earthquake of 9.1 magnitude in Sumatra, Indonesia, which led to a tsunami killing 230,000 people, was probably precipitated by the moon’s influence. Same was the case with the 2011 temblor in Japan, which took at least 15,000 lives and led to a meltdown at the Fukushima nuclear reactor.

The gravitational pull of the moon leads to Earth’s tides when it moves over the planet’s surface. When the satellite is directly over a specific spot, it attracts the water there in the direction of itself, making the ocean on that side of Earth (and the opposite side) to bulge.

The effect is highly evident when the Earth, sun and the moon are aligned, as the sun is able to contribute its bulk to strengthen the gravity of the moon. This is the reason people often link full moons and new moons with the most drastic high tides.

http://norcal.news/news/22974-gravit...trigger-quakes