日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 M (領域外・複数領域) » M-IS ジョイント

[M-IS02] 地球掘削科学

2019年5月27日(月) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:山田 泰広(海洋研究開発機構 海洋掘削科学研究開発センター)、針金 由美子(産業技術総合研究所)、黒柳 あずみ(東北大学学術資源研究公開センター東北大学総合学術博物館)、山口 耕生(東邦大学, NASA Astrobiology Institute.)

[MIS02-P09] ICDP DSeis 6: Deformation Rate Analysis of the M5.5 aftershock zone core - stress concentration at reflective intrusives

*兼松 慎1東 充也1矢部 康男2阿部 周平2Watson Bryan3Durrheim Ray3小笠原 宏1 (1.立命館大学 理工学部 物理科学科、2.東北大学理学研究科、3.Witwatersrand大)

キーワード:地震発生場、応力測定、DRA

ICDP drilling into the aftershock zone of the 2014 M5.5 earthquake near Orkney, South Africa commenced on 2017 and was completed in 2018. Ishida et al. (2018) and Sugimura et al. (2019; ICDP DSeis 5) report on spatial variation of differential stress in a plane perpendicular to the borehole axis. It is ideal to have different stress component especially at critical location where significant characteristics were found. Deformation Rate Analysis (Yamamoto, 2009) can measure stress in any direction although the method takes time and the specimen are not reusable for other test. So, we planned to selected samples where characteristic spatial variation was found by DCDA method (Ishida et al. 2018 and Sugimura et al. 2019). It was confirmed also in normal stress component along the borehole axis that stress was concentrated at the intrusive at about 400m.



This is one of nine ICDP DSeis papers (ICDP DSeis 1-9) presented in JpGU 2019. Refer other papers for other topics on drilling, logging, other stress measurement, fault materials, comparison with calculated stress, legacy 3D seismic reflection data, and relocated aftershocks.



Acknowledgement: The DSeis team includes co-authors of the papers ICDP DSeis 2-9 and members shown at https://www.icdp-online.org/projects/world/africa/orkney-s-africa/details/. We thank Harmony Gold, Anglogold Ashanthi, Lesedi, Digital Surveying, OHMS, Seismogen, 3D Geoscience. ICDP, JSPS, SA NRF, MEXT Japan, US NSF, German DRF, and Ritsumeikan Univ. financially support the project.