Yanosuke Otsuka

Geologist. Born in Tokyo. Graduated from the Department of Geology at Tokyo Imperial University in 1929 (Showa 4). While still a student, he conducted thorough field surveys, and through his research into the stratigraphy and geomorphological development history of the Shonan region in the Tertiary and Quaternary periods, he elucidated the Cenozoic geological structure throughout Japan. Meanwhile, as a member of the Earthquake Research Institute at the University of Tokyo, he published many reports on earthquakes, volcanoes, and hot springs, and also made a name for himself in fossil research. His 1931 Iwanami Lectures: Quaternary Period was recognized as a groundbreaking achievement, and in 1938 he received a doctorate in science for his book Crustal Deformation in the Tertiary Period of Japan. He conducted four surveys of the continent from 1939 onwards, and in 1943 he became a professor at the University of Tokyo, teaching stratigraphy and East Asian geology, and also lectured on physical geography as a professor at Tokyo University of Literature and Science. In the same year, he contracted dengue fever during a survey trip to Indochina, which led to poor health, and he died at the age of 47. His main work was The Geological Structure of Japan, and he also wrote 250 papers. It also had a major impact on related fields such as geography and seismology.

[Hiroshi Ishiyama]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

地質学者。東京生まれ。1929年（昭和4）東京帝国大学地質学科を卒業。在学中から徹底した野外調査を重ねて、湘南(しょうなん)地方の第三紀・第四紀の層序、地形発達史の研究から、全国各地の新生代地質構造を解明した。一方、東大地震研究所員として地震、火山、温泉の調査報告も多く、化石研究でも一家を成した。1931年の『岩波講座・第四紀』は画期的業績と評価され、1938年『日本の第三紀の地殻変形』で理学博士となる。1939年から4回にわたって大陸の調査を行い、1943年東大の教授に進んで層位学と東亜地質を、兼任の東京文理科大学教授としては自然地理を講じた。同年インドシナの調査旅行でデング熱にかかってから健康を害し、47歳で死去した。主著『日本の地質構造』ほか著書論文250編。地理学、地震学などの関連分野にも大きな影響を与えた。

［石山　洋］

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