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Ishii, Eiichi
no journal, ,
Major conductive fault-zone fractures already involve the network of flow paths developed by past shear-induced dilation, and therefore the transmissivities are inferred to no longer increase significantly even if shear failure newly occurs within those fractures. This study verifies this inference by injection tests for a fault-zone fracture in mudstone which was detected as a flow anomaly by flowing-fluids electric conductivity logging in a borehole at the Horonobe area, Japan. The tests applied a new method where shear displacement along the fault-zone fracture during injection is monitored by measuring pressures of conventional straddle-sliding-packers. For the fracture, the tests yielded a fast slip (
0.04-0.05 mm/s) following a slow slip ( 0.001 mm/s), reduction of shear strength and fracture normal stiffness after those slips, and irreversible shear displacement of 0.40-0.47 mm after injection. Comparing the transmissivities of the fracture before and after these shear slips shows no significant difference. These results suggest that the transmissivities of fully conductive fault-zone fractures are unlikely to significantly increase further even if the fractures reactivate, which supports the previous empirical model to estimate the highest potential transmissivities of fault-zone fractures from the rock strength and stress condition.
Yonaga, Yusuke; Sano, Naomi*; Amamiya, Hiroki*; Niwa, Masakazu; Yasue, Kenichi*
no journal, ,
no abstracts in English
Fukuda, Shoma*; Sueoka, Shigeru; Kohn, B.*; Tagami, Takahiro*
no journal, ,
no abstracts in English
Sueoka, Shigeru; Tagami, Takahiro*
no journal, ,
no abstracts in English
Kawakami, Tetsuo*; Sueoka, Shigeru; Tagami, Takahiro*
no journal, ,
no abstracts in English
Kajita, Yuya*; Sueoka, Shigeru; Fukuda, Shoma*; Hasebe, Noriko*; Tamura, Akihiro*; Morishita, Tomoaki*; Tagami, Takahiro*
no journal, ,
no abstracts in English
C ages of wood fragments from the Nashikonogawa Fromation in the Achi area, Nagano Prefecture, central JapanKojima, Satoru*; Miura, Chiaki*; Fujita, Natsuko
no journal, ,
no abstracts in English
Shimada, Koji; Goto, Akira; Sasaki, Akimichi*; Terusawa, Shuji*; Komatsu, Tetsuya
no journal, ,
We tried an objective expression of directional distribution of lineaments utilizing the directional statistics for the high interpretability. Directional statistics of lineaments at the shear zone in southern Kyushu indicate that the length weighted directional distribution of lineaments are decomposed into five von Mises distributions. An objective extraction of the East-West lineament concentration ereas was concordant with qualitative understanding by means of rule of thumb, judgement at a glance or rose-diagram.
Higa, Saki*; Terusawa, Shuji*; Niwa, Masakazu; Shimada, Koji; Komatsu, Tetsuya
no journal, ,
In the southern Kyushu shear zone, geological investigation along north-south ca.27 km area near aftershock distributions of the 1997 Kagoshima-ken hokubu earthquake depict striation and sense of shear of small faults. As a result of stress inversion analysis, it was found that the NE-SW compression and NW-SE tension stress fields, consistent with the left-lateral shear of the southern Kyushu shear zone, is localized within central 2 km north-south width zone.
Komatsu, Tetsuya; Sueoka, Shigeru; Hiura, Yuki; Kitamura, Yo*; Sanga, Tomoji*
no journal, ,
no abstracts in English
Komatsu, Tetsuya; Sueoka, Shigeru; Niwa, Masakazu; Ishimaru, Tsuneari
no journal, ,
no abstracts in English
Sasaki, Akimichi*; Komatsu, Tetsuya; Miwa, Atsushi*; Terusawa, Shuji*; Kagohara, Kyoko*; Higa, Saki*
no journal, ,
no abstracts in English
Matsuoka, Toshiyuki; Miyakawa, Kazuya; Hayano, Akira; Nakayasu, Akio*; Sasamoto, Hiroshi; Masuoka, Kentaro*; Yamamoto, Hajime*
no journal, ,
JAEA have been developing the investigation and the evaluation methods for understanding the spatial distribution of hydrogeological and geochemical condition and their long-term stabilities. This paper summarized the preliminary analyses of groundwater flow simulation focused on the meteoric water infiltration as a test case of Horonobe area.
Kametaka, Masao*; Tanaka, Yumiko*; Iwasaki, Etsuo*; Aoki, Kazuhiro; Tanaka, Yukumo; Yoshida, Takumi; Seshimo, Kazuyoshi
no journal, ,
no abstracts in English