Recurrence records of Nankai Trough Tsunamis found in lacustrine deposits during last 6000 years

2015 Fiscal Year Final Research Report

• Project/Area Number: 25282112
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: Kochi University
• Principal Investigator: OKAMURA Makoto 高知大学, 防災推進センター, 教授 (10112385)
• Co-Investigator(Kenkyū-buntansha): MATSUOKA Hiromi 高知大学, 教育研究部自然科学系, 准教授 (60222296)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 津波堆積物 / 南海トラフ地震 / 地震履歴 / 古地震

Outline of Final Research Achievements

We continue paleo-seismic studies through Late Holocene-time in coastal marsh ponds along the Nankai Trough. These ponds which situate co-seismic subsidence areas have continuous muddy sediment stratigraphy and sporadic tsunami sediment composed of coarse material. Total 13 cores collected from a coastal pond Zasa-ike which locate behind beach-ridge along southeastern coast of Kii Peninsula. The remarkable event found in sediment, which are 2000-2300yBP (=2K event). 2K event consists thick sand, well rounded gravel in chaotic mud with wood fragment derived from forests surrounding the lakes. The 2K events have also found widely, not only Kii Peninsula but southern Shikoku through the Nankai Trough.

Free Research Field

地震地質学