Japan Geoscience Union Meeting 2019

Presentation information

[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS02] Drilling Earth Science

Mon. May 27, 2019 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall8, Makuhari Messe)

convener:Yasuhiro Yamada(Japan Agency for Marine-Earth Science and Technology (JAMSTEC), R&D Center for Ocean Drilling Science (ODS)), Yumiko Harigane(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Azumi Kuroyanagi(Tohoku University Museum, The Center for Academic Resources and Archives, Tohoku University), Kosei E. Yamaguchi(Toho University and NASA Astrobiology Institute)

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

*Kanematsu Makoto1, Mitsuya Higashi1, Yasuo Yabe2, Shuhei Abe2, Bryan Watson3, Ray Durrheim3, Hiroshi Ogasawara1 (1.Ritsumeikan Univ., 2.Tohoku Univ., 3.Univ. Witwatersrand)

Keywords:Seismogenic zone, Stress Measurement, 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.