POPULAR SCIENCE 



THE ERUPTION OF SAKURA-JIMA ON 



JANUARY 12, 1914 



By Charles Davison, Sc.D., F.G.S. 



On January 12, 1914, a violent eruption occurred in the volcano 

 of Sakura-jima near the southern extremity of Japan. The 

 eruption is remarkable for the vast amount of material ejected 

 within a brief interval of time, for the extraordinary crustal 

 movements within and near the volcano, for the close connection 

 of the eruption with a strong tectonic earthquake, and for the 

 anomalous forms of the areas within which the loud detonations 

 were heard. The various phenomena of the eruption have 

 been examined by Prof. F. Omori, the well-known director of 

 the Seismological Institute at Tokyo. The memoirs * in which 

 his investigations are described are among the most important 

 of recent contributions to our knowledge of volcanic action, 

 and are of sufficient importance to justify the somewhat lengthy 

 abstract which is contained in the following pages. 



Topography. — From the south coast of Kyushu, the most 

 southerly of the main islands of the Japanese empire, the Bay of 

 Kagoshima runs in a northerly direction for more than forty 

 miles inland (fig. 1). Sakura-jima, until 1914 an island but 

 now a peninsula, rises from the northern portion of the bay. 

 It was separated from the main island by channels, that on the 

 west side varying in width from i| to 2\ miles and in depth 

 from 38 to 77 fathoms, that on the east side (the Straits of Seto) 

 being less than half a mile wide and 45 fathoms in maximum 

 depth. In the northern portion of the bay, which is surrounded 

 as a rule by a steep coast, the depth of water is nearly uniform, 

 ranging from about 70 to 107 fathoms. It is a basin similar, 

 perhaps, in origin to the deep lakes which lie behind the coastal 

 volcanoes of Usu-san and Tarumai-san in the northern islands 

 of Hokkaido. 



1 " The Sakura-jima Eruptions and Earthquakes," Bulletin of the Imperial 

 Earthquake Investigation Committee (Tokyo), vol. viii. pp. 1-34 (1914X 3 D_I 79> 

 181-321 (1916). 



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