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Japan, strong earthquake of magnitude 6.9 in Miyazaki prefecture

Today at 1.19pm (local time), a violent earthquake of magnitude 6.9 hit the southern coast of JapanMiyazaki Prefecture. The earthquake shock recorded a epicenter at sea, a few km away from the mainland, and a hypocenter rather superficial and equal to approximately 30km. The shock, in reality, was followed by a seismic sequence, with an earthquake from 3.9 (at 1.35pm) and one from 4.1 (at 1.42pm). At the moment we are not aware of damage to things and/or people but considering the country’s high anti-seismic preparation, it is probable that there were no particular inconveniences. The epicenter area is close to where two violent tremors of magnitude 7.1 and 6.9 were recorded last August, and for which the Japanese meteorological agency had issued a warning for an earthquake of magnitude 8.0 or higher (fortunately, this did not occur ).

At the same time it is important to highlight how the tsunami warning was issued, even if experts believe that earthquakes of this magnitude are not capable of generating tsunamis in that area.

As regards the intensity of the shock, the Japan Meteorological Agency gives it a maximum value of 5-on a local scale ranging from 1 (not intense at all) a 7 (maximum intensity). The image below shows the intensity map: Warmer colors correspond to areas where the shock was felt stronger waywhile the Red X indicates the epicenter.

Image
Credit: Japan Meteorological Agency

From a geological point of view we can say that the area is frequently subject to earthquakes. In fact, here the subduction of the occurs Philippine plate below that of Sunda, giving rise to a series of earthquakes and volcanoes throughout the Japanese archipelago. As also reported by the USGS, the subduction runs for over 3000 km and seismicity in some areas can even occur 600 km deep.