Geomorphological and Geological Study on Unknown Huge Tsunamis along the Nankai Trough

2014 Fiscal Year Final Research Report

• Project/Area Number: 24300319
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Geography
• Research Institution: Hosei University (2013-2014); Hiroshima University (2012)
• Principal Investigator: MAEMOKU Hideaki 法政大学, 文学部, 教授 (50222287)
• Co-Investigator(Kenkyū-buntansha): SHISHIKURA Masanobu 国立研究開発法人産業技術総合研究所, 地質調査総合センター(活断層・火山研究部門), 研究グループ長 (00357188) ; NAMEGAYA Yuichi 国立研究開発法人産業技術総合研究所, 地質調査総合センター(活断層・火山研究部門), 主任研究員 (90466235)
• Co-Investigator(Renkei-kenkyūsha): ECHIGO Tomoo 地域地盤環境研究所, 地球科学研究部門・地形, 地質グループ員 (60450904) ; YOKOYAMA Yusuke 東京大学, 大気海洋研究所, 教授 (10359648) ; MIYAIRI Yosuke 東京大学, 大気海洋研究所, 特任研究員 (30451800) ; FUJINO Shigehiro 筑波大学, 生命環境科学研究科, 助教 (80466234)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 津波 / 津波漂礫 / 完新世隆起石灰岩 / 津波堆積物 / 南海トラフ / 南海地震 / 笠嶋遺跡 / プレート境界

Outline of Final Research Achievements

This study aims to clarify the unknown huge tsunamis occurred along the Nankai Trough, pacific coast of southwestern Japan since mid Holocene. We surveyed and measured tsunami boulders scattered on the wave cut bench from the quartz porphyrite dyke, and heights and 14C ages of raised Holocene limestones around the southern tip of Kii Peninsula, Pacific coast of southwestern Japan. We also got some geological cores from sand bar where Kushimoto town spread over. The results of the study are 1) most boulders more than 1m in diameter could not be moved by typhoons or storm surges, most of the boulders could be possibly moved by more than Hoei class tsunami, 2) huge tsunamis which could move boulders have been occurred approximately every 500 years since 6000BP by tsunami sediments analysis from all core boring.

Free Research Field

自然地理学