- 著者
- Kuno Hisashi
- 出版者
- 東京帝国大学地震研究所
- 雑誌
- 東京帝国大学地震研究所彙報 (ISSN:00408972)
- 巻号頁・発行日
- vol.14, no.4, pp.619-631, 1936-12-21
Warping of the slopes of the Taga and Yugawara volcanoes (lower Pleistocene) caused subsidence of the Tanna and Tasiro basins and at the same time elevation of the area between Kuro-dake and Nirayama. Later, this district was affected by the Tanna fault. The block on the western side of the fault was displaced about 1 km horizontally southward for the greater part of the fault line, and was elevated about 100 meters or more in its southern part, relatively to the block on its east. The fault displacement that occurred at the time of the earthquake of 1930 is similar in character to the above-mentioned displacement that occurred in geological times. The fault displacement itself is not the sole cause of the origin of the Tanna basin. This basin was formed chiefly through down-warping of the volcanic slope. As a result of the fault displacement, the topography of the basin became somewhat more complex than it had been before.
- 著者
- Kuno Hisashi
- 出版者
- 東京帝国大学地震研究所
- 雑誌
- 東京帝国大学地震研究所彙報 (ISSN:00408972)
- 巻号頁・発行日
- vol.14, no.1, pp.92-103, 1936-03-20
丹那隧道内に於ける實際の岩石露出面の觀察,多数の岩石標本の採集,並びに隧道附近地表面の地質調査等の結果を基にこて,丹那隧道東半部の地質斷面圖(第1圖)を作製これ.本論文にては,此の斷面圖に就いて各部分に於ける諸種岩層の産状,相互關係,構造並びにその構成物質の岩石學的性質の大略等を記載した.本研究の結果,此の附近地域の地質構造が可なり明になつた.特に今まで多数の學者によつて議論されて來た丹那盆地の地下構造が判明した.丹那盆地は從來唱へられた如く火口跡でもなく單なる地溝でもなく,叉單に鍋状陷没のみによつて生じたものでもない.それは多賀火山の噴出物層が主として撓曲沈降して生じた構造盆地である事が分つた.尚本盆地の成因に關する詳しい議論は他の機會に譲る.