Tsunami records of Showa, Ansei and Houei Nankai earthquakes in lake sediments.

湖泊沉积物中昭和、安政和丰永南海地震的海啸记录。

• 批准号: 13640464
• 负责人: MATSUOKA Hiromi
• 金额: $ 2.18万
• 依托单位: Kochi University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640464/
• 关键词: tunami sediments; Nankai earthquakes; piston coring; tunami; ピストンコアラー

The purpose of this study is to relate the tsunami traces in the lake sediment and the historical earthquake records. In order to achieve this purpose, we developed corers in which to surely collect the surface sediment is possible. Small piston corer, gravity corer and coring attachment for small vibration hammer were newly made for this study.Seven core samples were collected by using these core samplers in the Tadasuga-ike, Susaki City, Kochi prefecture. Tadasuga-ike is flesh water pond and was invaded by sea water of tsunami at the Shouwa Nankai earthquake. Remarkable colored layers ware observed at the 35-40cm, 40-45cm and 60cm beneath the bottom surface. The presence of marine calcareous nannofossils at the 60cm layer indicates that sea water flowed in the pond at that time.Pb210 method was used for determination of sedimentary rate of core samples. The sedimentary rate of core SS02-04 and 07 was 1.0 cm/yr and 0.9 cm/yr respectively. These rates mean that the remarkable 60cm layer accumulated about 60 years ago and correspond to the Shouwa Nankai earthquake.

本研究的目的是将湖泊沉积物中的海啸痕迹与历史地震记录联系起来。为了实现这一目的，我们开发了取芯器，可以确保收集表层沉积物。本研究新研制了小型活塞取样器、重力取样器和小型振动锤取样器，并利用这些取样器在高知县须崎市忠助池采集了7个岩心样品。Tadasuga池是肉水池，在Shouwa南海地震中被海啸的海水入侵。在35- 40 cm、40- 45 cm和60 cm处有明显的着色层。在60 cm处有海相钙质超微化石的存在，说明当时有海水流入该池塘。SS 02 -04和07孔的沉积速率分别为1.0cm/yr和0.9cm/yr。这些速率意味着60 cm层的显著积累大约在60年前，并对应于寿和南海地震。