The Survey with ROV on Tsuzuraozaki Underwater Sire in the Lake Biwa

2018 Fiscal Year Final Research Report

• Project/Area Number: 15H03271
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Archaeology
• Research Institution: Ritsumeikan University
• Principal Investigator: Yano Kenichi 立命館大学, 文学部, 教授 (10351313)
• Co-Investigator(Kenkyū-buntansha): 島田 伸敬 立命館大学, 情報理工学部, 教授 (10294034) ; 川村 貞夫 立命館大学, 理工学部, 教授 (20186141)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 水中考古学 / ROV / 湖成鉄 / 葛籠尾崎 / 湖底遺跡 / 水中ロボット / SSBL / 音響測位

Outline of Final Research Achievements

Tsuzuraozaki underwater site in the Lake Biwa has been known as a unique underwater site where a lot of pottery of Jomon,Yayoi,Kofun,Nara and Heian periods were recovered by local fishermen. The water depth of the site extends to about 80m. There are various theories as to the origin of the site, and it has not been decided. In order to clarify the origin of the site, we developed oliginal underwater robots for the survey of the site to get the GPS information and images of each ancient pot on the bottom of the lake. As a result, it was found that a large number of pottery dated after the 7th century had been submerged in the south waters of the Tsuzuraozaki Cape. Since the pottery of Jomon, Yayoi and Kofun periods dated before the 7th century had been discovered in the east waters of Tsuzuraozaki Cape, it turned out that the submersion areas of pottery moved from the east waters to the south waters after 7th century.

Free Research Field

考古学

Academic Significance and Societal Importance of the Research Achievements

葛籠尾崎湖底遺跡は水深が深いため、潜水調査が困難である。本研究は、水中ロボットを利用して湖底の土器画像と位置情報を取得する方法で、土器の分布を明らかにした。その結果、葛籠尾崎湖底遺跡では土器の水没している水域が大きく2か所にわかれ、しかもそれぞれで土器の年代が異なるという新しい事実が判明した。特に、新たに土器分布の実態が判明した葛籠尾崎南の水域は竹生島に面しており、7世紀以降の土師器皿（もしくは須恵器坏）が多いことは湖水に関係する儀礼で土器が水没した可能性がある。水中ロボットによる湖底調査が有意義であることが示されたので、今後、琵琶湖の他の水域でも行う必要がある。