[M-IS11] 津波堆積物

[MIS11-P11] 浜名湖と富士五湖堆積物を用いた津波および古地震研究の展望

*中村 淳路¹、Boes Evelien²、Brückner Helmut³、De Batist Marc²、藤原 治¹、Garrett Edmund⁴、Heyvaert Vanessa⁴、Hubert-Ferrari Aurelia⁵、Lamair Laura⁵、宮入 陽介⁶、オブラクタ スティーブン⁷、宍倉 正展¹、山本 真也⁸、横山 祐典⁶、The QuakeRecNankai team (1.国立研究開発法人産業技術総合研究所、2.Ghent University、3.University of Cologne、4.Royal Belgian Institute of Natural Sciences、5.University of Liège、6.東京大学大気海洋研究所、7.秋田大学、8.山梨県富士山科学研究所)

キーワード：津波堆積物、古地震、浜名湖、富士五湖

Great earthquakes have repeatedly occurred along the Nankai Trough, the subduction zone that lies south of Japan’s heavily industrialized southern coastline. While historical records and geological evidence have revealed spatial distribution of paleo-earthquakes, the temporal variation of the rupture zone is still under debate, in part due to its segmented behavior. Here we explore the potential of the sediment records from Lake Hamana and Fuji Five Lakes as new coherent time series of great earthquakes within the framework of the QuakeRecNankai project.
We obtained pilot gravity cores form Lake Hamana and the Fuji lakes Motosu, Sai, Kawaguchi, and Yamanaka in 2014. In order to image the lateral changes of the event deposits, we also conducted reflection-seismic survey. Based on these results, potential coring sites were determined and then 3–10 m long piston cores were recovered from several sites in each lake in 2015. The cores consist of 2 m long sections with 1 m overlaps between the sections allowing us to reconstruct continuous records of tsunamis and paleo-earthquakes. In this presentation we introduce the progress of QuakeRecNankai project and discuss the potential of the lakes as Late Pleistocene and Holocene archives of tsunamis and paleo-earthquakes.