Japan, situated on the “Ring of Fire” arc of volcanoes and oceanic trenches which partly encircles the Pacific Basin, accounts for about 20 percent of the world's earthquakes of magnitude six or greater. Tokyo sits on the junction of four tectonic plates: the Eurasian, North American, Philippine and Pacific. The sudden bending or breaking of any plate can trigger an earthquake. A tremor occurs in Japan at least every five minutes.
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