Physical characteristics of Shionohira fault damage zone and kuruma fault damage zone based on laboratory tests

Nishiwaki, Takafumi*; Ogawa, Koji*; Aoki, Kazuhiro ; Yoshida, Takumi

Various physical and mechanical tests were performed on shallow borehole cores ( 30 m) taken from the activated Shionohira and the non-activated Kuruma faults associated with the April 2011 Fukushima-ken Hamadori earthquake. The results showed (1) low strength constants and elastic constants for the fault damage zone samples compared to the host rocks; (2) different physical properties for fault gouge, fault breccia, and Cataclasite of the fault damage zone; and (3) for fault gouge, the importance of considering the stress factor on the fault plane. Data accumulation from various fault damage zones is needed to gain better understanding of the physical properties of the fault damage zone.