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Wakahama, Hiroshi*; Nojo, Haruka*; Aoki, Kazuhiro; Imai, Hirotaro; Guglielmi, Y.*; Cook, P.*; Soom, F.*
Oyo Chishitsu, 64(5), p.236 - 254, 2023/12
Upon the Hamadori earthquake (Mw 6.7) of 11 April 2011, coseismic surface deformation of 14 km running NNW to SSE in southeast Fukushima Prefecture occurred and was newly named the Shionohira Fault. However, no surface deformation was observed along the Kuruma Fault which is a southern extension of the Shionohira Fault. Fault injection tests using SIMFIP method at the Shionohira site on the former active segment and the Minakamikita site on the latter inactive segment were conducted to evaluate the activity of the two faults. Based on hydraulic responses to water injection into the fault rupture zone in the monitoring boreholes at the two sites, hydraulic properties of the area across the fault zone were estimated using the GRF model (Barker, 1988). The results obtained on hydraulic conductivity, specific storage and flow dimension were consistent with those in the domestic and international literature. The hydraulic conductivity and specific storage were larger in Shionohira than in Minakamikita. The flow dimension of Shionohira was three-dimensional, while that of Minakamikita was found to be a two-dimensional fractional flow. In addition, it is understood that the volumetric expansion occurs in the former site in the triaxial direction and the latter in the uniaxial with the comparison between the uniaxial expansion coefficient calculated from the results of SIMFIP displacement measurements and the specific storage in the hydraulic analysis. The difference in the hydraulic parameters between the two sites corresponded to the difference in the spatial development of fractures considered to be the "water passway," indicating the possibility of a correlation between the parameters and the different possible causes for fault activity at the two sites.
Wakahama, Hiroshi*; Nakata, Mitsuhiko*; Hiroki, Minenari*; Futakuchi, Katsuhito*; Okada, Akio*
JNC TJ7440 2003-004, 128 Pages, 2003/03
JNC-TJ7440-2003-004.pdf:15.57MB
This report describes the results of installation of the long-term groundwater monitoring system into borehole DH-2 as a part of the Regional Hydrogeological Study and Mizunami Underground Research Laboratory Project. DH-2 was driglled with 100mm diameter through Toki-granite to the depth of 501meter below the ground level, in which 5inch-steel-casing pipe was inserted to the depth of 171m. The monitoring system was composed of concentrically arranged seven open PVC(polyvinyl chloride)-stand-pipes("Piezo-pipes"), housed within outer 4inch PVC-casings, followed by 3inch PVC-casings, packers and several stainless steel units. In the system, seven monitoring zones were isolated by expandable rubber type packers inflating with water. From the view point of quality assessment, leak-off tests were conducted for all of 7 packers before the shipment and the installation at the site. In terms of individual casing joints, air-tight inspections were carried out ...
Watanabe, Takahiro*; Tanaka, Yukumo; Aoki, Kazuhiro; Guglielmi, Y.*; Cook, P.*; Soom, F.*; Wakahama, Hiroshi*; Nojo, Haruka*; Iwasaki, Etsuo*; Kametaka, Masao*; et al.
no journal, ,
no abstracts in English
Nanjo, Isao; Mizuno, Takashi; Murakami, Hiroaki; Amano, Yuki; Hosoya, Shinichi*; Wakahama, Hiroshi*; Yamashita, Riyo*
no journal, ,
This study aimed to develop a hydrochemical monitoring system for in-situ groundwater. JAEA has developed the hydrochemical monitoring system which is available at underground facility focused on low-permeable sedimentary rocks. After performance test, it can be demonstrated that the monitoring system is workable completely at 350m depth research gallery.
Aoki, Kazuhiro; Wakahama, Hiroshi*; Nojo, Haruka*; Iwasaki, Etsuo*; Kametaka, Masao*; Tanaka, Yukumo; Yoshida, Takumi; Seshimo, Kazuyoshi
no journal, ,
no abstracts in English
