Hi-resolution analysis of tsunami event from coastal area in Shikoku and Kyushu

本研究的主要目的是重建南海地震间隔记录海啸沉积物从海岸泻湖沿着九州和四国岛。在前人研究的基础上，从1300 ~ 4500 yBP的时间段内，共分离出14个海啸沉积物。这些海啸沉积物中还包括地壳沉降事件等海洋浮游生物产层。在这些海啸记录中，有8层3500年来的大地震，平均间隔为350年。通过对九州龙神池的进一步研究，我们确定了与Tadasu-ike同时对应的海啸事件的年龄。它们的年龄分别为1600 yBP、1900 yBP、2600 yBP、3000 yBP和3300 yBP。位于四国中部的神奈川池也发生了三次巨大的海啸事件，这三次海啸事件与过去1000年的历史记录相一致，被称为Hoei，Shohei和Tenmu Nankai地震。通过沿着Nanakai槽的九州和四国的两个长距离站点，可以确认Hoei型Nankai地震等巨大地震系列。

The main purpose of this study is reconstruction of the Nankai Earthquake interval recorded as tsunami sediment from shore-lagoon along the Kyushuu and Shikoku Island. Based on our previous study fourteen tsunami sediments were distinguished from 1300yBP to 4500yBP interval. These tsunami sediments are also included crustal subsidence events such as marine plankton yield interval layers. Among these tsunami records eight layers through 3500 years shows remarkable huge earthquake, which interval has 350 years in average.Additional work on Ryujin-ike in Kyushu, we determined the age of tsunami event which correspond to Tadasu-ike simultaneously. These age are 1600yBP, 1900yBP, 2600yBP, 3000yBP and 3300yBP respectably. Kaniga-ike situated in central Shikoku also yielded three huge tsunami events correlatable to historical records known as Hoei, Shohei and Tenmu Nankai Earthquakes for past 1000 years.Huge earthquake series such as Hoei-type Nankai Earthquake are determined confirmably through two long-distanced sites in Kyushu and Shikoku along the Nanakai Trough.