GEOLOGY OF JAP A IV 69 



Japan is 165, of which 54 are active. Mount Aso in Kyfisim has 

 the largest crater in the world, its diameter measuring 22 km. Mount 

 Fuji is the loftiest of all tlie volcanoes of Japan and attains a height 

 of 3,778 m. above the sea level. They are all built up of andesites 

 and their derivatives, which are often basaltic. 



The volcanoes of Japan can be grouped into several V'.)lc;iiiic zones 

 or chains. Of these the most conspicuous is the '' Fuji zone " which, 

 running across the middle of Honshu Island from the Sea of Japan 

 to the Pacific Ocean, divides North and South Japan. Beginning from 

 the north, we have such volcanoes as My5ko-zan, Togaknshi-yama, 

 Tateshiua-yama, Yatsuga-take, Fuji-san, Hakone-yama, Amagi-san, 

 etc., all belonging to this zone which continues into the Pacitic Ocean 

 through Izu Shichito (the Seven Islands), Ogasawara-jima (Bonin 

 Islands) and Iwo-jima (Sulphur Islands) and even further south to the 

 Mariana and Caroline Islands. 



The " Nasu chain " which forms the backbone or meridional 

 mountain range of North Japan, comprises the cones of Osore-zan, 

 Iwate-yama, Nasu-san, Nantai-san, Akagi-san, Haruna-san, Asama-yama, 

 etc. The continuation of the "Nasu chain " is found in Hokkaido, 

 giving rise to Komaga-take and the group of volcanoes in Iburi and 

 Shiribeshi. 



The " Chokai chain " also in North Japan, runs parallel to the 

 " Nasu chain " along the coast of the Sea of Japan and contains such 

 volcanoes as Ivvaki-san, Chokai-san, Gassan, etc. 



The '■' Chishima chain " extends from Tokachi-dake in the middle 

 of Hokkaido, through Meakan-dake and Oakan-dake in Kushiro, to 

 the volcanic islands of Chishima, and continues into the peninsula of 

 Kamtschatka. 



The " Hakusan chain " in South Japan runs along the coast of 

 the Sea of Japan, and contains several volcanoes such as Haku-san, 

 Dai-sen, Sambe-yama, etc. 



The '' Kirishima chain " is found near the western margin of the 

 island of Kyushu, having Kirisiiima-yama at its center. On the north, 

 it extends to Unzen-dake, while on the south it continues to the 

 volcanic islands of Krchinoerabu-jima, Suwanose-j ima, Takara-jima, 

 etc., in the Ryilkyu ai-c. 



A group of volcanoes near Aso-zan forms another zone with the 

 volcanoes of Unzen-dake and Tara-dake, v/here it meets the " Kiri- 

 shima chain " and continues eastwards in the dei^ressed area of the 



