300 JAPAN Figure Map showing the distribution of deep focus earthquakes and Quaternary volcanoes, overprinted on Figure (After Editorial Committee for the Geology of the Japanese Islands (2002).) Japan Systems Occasionally, shallow submarine earthquakes generate large tsunamis along both the Pacific and Japan Sea sides, particularly in northern Honshu and the Ryukyus The Great Kanto Earthquake (M 8.2; September 1923) killed over 140 000 people and destroyed a third of Tokyo and most of Yokohama The Meiji Sanrikuoki Earthquake (M 8.6; 15 June, 1896) caused a great tsunami of 38 m high, and killed about 22 000 people in the Sanriku coast of Iwate Prefecture, Pacific side of northern Honshu In the NE Japan System, the distribution of hypocentres along the seismic plane is smooth and continuous However, the dipping angle of the seismic plane, i.e., the boundary between the Eurasian Plate and the subducting Pacific Plate varies from place to place The average angle is about 30 under northern Honshu, but it is steeper under Hokkaido and the Izu-Ogasawara Islands The maximum depth of deep-focus earthquakes is estimated to be about 700 km The distribution of hypocentres in the SW Japan System is irregular and they are intermittently distributed beneath central Honshu and Shikoku The maximum depth in Kyushu is estimated to be about 200 km Geological Outline The geology of Japan (Figure 5) has been complicated by long-ranging subduction-related tectonic movement since the Early Ordovician The tectonic framework of the Japanese Islands is difficult to recognize owing to the thick covering of the Neogene and Quaternary sediments, which include volcanic rocks The Pre-Neogene rocks of the Japanese Islands are divided into the following four terranes: (i) the South Kitakami Terrane (Early Ordovician to Late Devonian accretionary terrane, comprising the Hida Gaien, South Kitakami, and Kurosegawa Belts); (ii) the Akiyoshi Terrane (Middle to Late Permian accretionary terrane, comprising the Akiyoshi, Maizuru, Suo, Ultra Tanba, and Joetsu Belts); (iii) the Mino Terrane (Early Jurassic to Early Cretaceous accretionary terrane, comprising the