Japan Geoscience Union Meeting 2025

Presentation information

[J] Poster

H (Human Geosciences ) » H-CG Complex & General

[H-CG20] Nuclear Energy and Geoscience

Sun. May 25, 2025 5:15 PM - 7:15 PM Poster Hall (Exhibition Hall 7&8, Makuhari Messe)

convener:Shinji Takeuchi(Department of Earth and Environmental Sciences, College of Humanities & Sciences, Nihon University), Takaomi Hamada(Central Research Institute of Electric Power Industry), Eiji Sasao(Japan Atomic Energy Agency)

5:15 PM - 7:15 PM

[HCG20-P02] Searching for effective combinations of methods and data sets for fault activity evaluation: the first-year results of a case study focusing on the Iga fault

*Tetsuya Komatsu1, Koji Shimada1, Takanori Ishihara1, Hiroaki Hakoiwa1, Takashi Hosoya2, Nayuta Matsumoto2, Tatsuya Terada2, Satoshi Goto2, Shigeru Okamoto3 (1.Japan Atomic Energy Agency, 2.Chuo Kaihatsu, 3.Hanshin Consultants)

Keywords:Fault, Fault core, Boring, Kizugawa fault zone, Iga fault

JAEA, Tono Geoscience Center, is currently planning to conduct research and development of activity evaluation methods for the faults without overlying strata for the period from FY2024 to FY2027. This R&D includes searching for and presenting effective combinations of methods and data sets for fault activity evaluation through some case studies. To this end, we will obtain and utilize boring cores that penetrate the fault cores of an active fault at near the surface and 100-200 m below the surface. We selected the Iga fault in the Kizugawa fault zone as an active fault suitable for the R&D, based on a literature review of active faults in Japan; historical materials and previous studies indicate the last activity of the fault occurred in 1854.

In FY2024, we carried out a boring survey to a depth of 25 m below the surface, successfully obtaining samples including a granite-sedimentary rock boundary believed to be the Iga fault. Additionally, we conducted unmanned aerial vehicle (UAV) laser scanning and seismic reflection surveys to understand the topography and subsurface structure at and around the site of the boring survey. We will present the results of these surveys, along with the R&D plan for FY2025.

Acknowledgments: This study was partly funded by the Ministry of Economy, Trade and Industry, Japan, as part of its R&D supporting program titled “Establishment of Technology for Comprehensive Evaluation of the Long-term Geosphere Stability on Geological Disposal Project of Radioactive Waste” (grant no. JPJ007597; fiscal year 2024).