2026-11-09 東京大学
南海トラフ近海の歴史地震震央と今回の試料採取地点
＜関連情報＞
- https://www.aori.u-tokyo.ac.jp/research/news/2026/20261109.html
- https://www.cambridge.org/core/journals/radiocarbon/article/sequential-highdensity-radiocarbon-dating-to-detect-invisible-event-layers-in-marine-sediments/E11AED48E35794E40D7297F81730DE21
海洋堆積物中の目に見えないイベント層を検出するための連続高密度放射性炭素年代測定 Sequential high-density radiocarbon dating to detect invisible event layers in marine sediments
Akiko Omura,Yusuke Yokoyama,Shoko Hirabayashi,Yosuke Miyairi and Juichiro Ashi
Radiocarbon Published:09 November 2026
DOI:https://doi.org/10.1017/RDC.2026.10255
Abstract
We present a unique application of radiocarbon measurements on hemipelagic sediments that uses continuous radiocarbon dating of total organic carbon (14CTOC age) to recognize event deposits. The 14CTOC age of sediments is not commonly used for age determination because total organic carbon includes various origins, such as marine, terrestrial, and reworked old fragments. In this study, the 14CTOC ages of some horizons were found to be older than those of the deeper ones through continuous 14CTOC measurements at 0.5- to 1.0-cm intervals. The reversal 14CTOC ages resulted not from the settlement of organic particles from the terrestrial environments, such as floodings, but from the submarine slope failures. Therefore, we can regard the reversal 14CTOC layers as event layers due to geohazards. After reconstruction of the age model using foraminiferal tests obtained from the sediment core used in this study, depositional ages of event layers were identified. Well correlation with historical natural disasters after the 15th century suggest validity of the method proposed by the current study.
