An Application of Hydraulic Tomography to a Large-Scale Fractured Granite Site, Mizunami, Japan.
While hydraulic tomography (HT) is a mature aquifer characterization technology, its applications to characterize hydrogeology of kilometer-scale fault and fracture zones are rare. This paper sequentially analyzes datasets from two new pumping tests as well as those from two previous pumping tests analyzed by Illman et al. (2009) at a fractured granite site in Mizunami, Japan. Results of this analysis show that datasets from two previous pumping tests at one side of a fault zone as used in the previous study led to inaccurate mapping of fracture and fault zones. Inclusion of the datasets from the two new pumping tests (one of which was conducted on the other side of the fault) yields locations of the fault zone consistent with those based on geological mapping. The new datasets also produce a detailed image of the irregular fault zone, which is not available from geological investigation alone and the previous study. As a result, we conclude that if prior knowledge about geological structures at a field site is considered during the design of HT surveys, valuable non-redundant datasets about the fracture and fault zones can be collected. Only with these non-redundant data sets, can HT then be a viable and robust tool for delineating fracture and fault distributions over kilometer scales, even when only a limited number of boreholes are available. In essence, this paper proves that HT is a new tool for geologists, geophysicists, and engineers for mapping large-scale fracture and fault zone distributions.
State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, China.|Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ, USA.
Yuanyuan
Y
Zha
Department of Hydrology and Water Resources, University of Arizona, Tucson, AZ, USA.
Tian-Chyi J
TJ
Yeh
Department of Earth and Environmental Sciences, University of Waterloo, Waterloo, Ontario, Canada.
Walter A
WA
Illman
Obayashi Corporation, Tokyo, Japan.
Tatsuya
T
Tanaka
Obayashi Corporation, Tokyo, Japan.
Patrick
P
Bruines
Japan Atomic Energy Agency, Mizunami, Japan.
Hironori
H
Onoe
Japan Atomic Energy Agency, Mizunami, Japan.
Hiromitsu
H
Saegusa
Department of Geophysics, Colorado School of Mines, Golden, CO, USA.
Deqiang
D
Mao
Department of Geosystem Sciences, Nihon University, Tokyo, Japan.
Shinji
S
Takeuchi
Research Center for Soil and Water Resources and Natural Disaster Prevention, National Yunlin University of Science and Technology, Douliu, Taiwan.
Jet-Chau
JC
Wen
D055593:Geological Phenomena; D060587:Groundwater; D007564:Japan; D012822:Silicon Dioxide; D014054:Tomography; D014872:Water Movements
C007886:granite; D012822:Silicon Dioxide