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Otani, Tomoyuki*; Yokoi, Kosuke*; Okazaki, Kazunari*; Nishimura, Yuki*; Kojima, Satoru*; Kuboshima, Koji*; Sasao, Eiji
no journal, ,
The orientation of microcracks was measured using the MIU-3 core penetrating the Tsukiyoshi fault to clarify the relation of the microcrack distribution near the fault. Attitude of microcracks in quartz grains in granite are measured under the optical microscope with the universal stage using three perpendicular thin sections. The healed microcracks was probably formed prior to the sealed microcracks. Both healed and sealed microcracks with moderate dip appears near the fault. The distribution of microcracks with moderate dip shows that the preferred orientation of microcracks near the fault is different from that far from the fault. The distribution of the sealed microcracks with moderate dip is narrower than that of the healed microcracks. This shows that the healed microcracks with moderate dip was developed in the intact granite at the earlier stage of the faulting history, and the sealed microcracks was in the weak fault zone which has repeated rupturing and healing at the later.
Shimo, Michito*; Yokoi, Satoru*; Miyakawa, Kazuya; Niwa, Masakazu; Matsuoka, Toshifumi*; Tokunaga, Tomochika*
no journal, ,
In this presentation, we report several preliminary studies to detect methane seepage using a portable gas analyzer by cavity ringdown spectroscopy.
Yokoi, Satoru*; Shimo, Michito*; Miyakawa, Kazuya; Niwa, Masakazu; Matsuoka, Toshifumi*; Tokunaga, Tomochika*
no journal, ,
In this presentation, we report methane gas seepages along an anticlinal axis in the Horonobe area, northern Hokkaido, and discuss migration paths from an underground reservoir.