Integrated study on the history of earthquake and tsunami, and the process of coastal uplift along the active tectonic zone of the eastern margin of the Japan Sea

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K01151
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 04010:Geography-related
• Research Institution: National Institute of Advanced Industrial Science and Technology
• Principal Investigator: Shishkura 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, 研究グループ長 (00357188)
• Co-Investigator(Kenkyū-buntansha): 前杢 英明 法政大学, 文学部, 教授 (50222287)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 日本海東縁 / 地震 / 隆起 / 海成段丘

Outline of Final Research Achievements

Traces of crustal movement (uplift and subsidence) mainly caused by past earthquakes were investigated along the eastern tectonic margin of the Sea of Japan in Yamagata, Niigata, and Ishikawa prefectures (Noto Peninsula) and south-west Hokkaido (Okushiri Island). As a result, the distribution of Holocene marine terraces was confirmed in each area. The uplifted terraces on the coast of Yamagata Prefecture and the Noto Peninsula were recorded only a few 10 cm uplift in the past millennium, while those in Okushiri Island subsided during the 1993 Hokkaido Nansei-oki Earthquake, and have not recovered even 30 years after the earthquake. Because the marine terrace was newly formed during the 2024 Noto Penisula earthquake due to a few meter uplift, future earthquakes with large uplift are anticipated in each region.

Free Research Field

古地震学，活断層

Academic Significance and Societal Importance of the Research Achievements

本研究では，日本海東縁変動帯沿岸での過去の地震による隆起や沈降の状況と長期的な変動を示す海成段丘の分布との関係を解明する上での貴重なデータを取得した．特に能登半島において2022年に海岸の測量調査を実施していたことで，翌2023年5月のM6.5の地震，そして2024年1月のM7.6の地震における地盤の隆起を正確に捉えることができたことは非常に大きな成果といえる．これは地震性地殻変動と断層活動の様式を解明する上での学術的な意義だけでなく，地震災害において隆起による社会的影響を評価するうえでも重要であり，社会的な意義も大きい．