HFB-1 borehole survey data collection

Miyakawa, Kazuya; Hayano, Akira; Sato, Naomi; Nakata, Kotaro*; Hasegawa, Takuma*

JAEA-Data/Code 2023-009, 103 Pages, 2023/09

JAEA-Data-Code-2023-009.pdf:9.29MB
JAEA-Data-Code-2023-009-appendix1(DVD-ROM).zip:271.51MB
JAEA-Data-Code-2023-009-appendix2(DVD-ROM).zip:883.78MB
JAEA-Data-Code-2023-009-appendix3(DVD-ROM).zip:10.29MB

This borehole investigation was carried out to confirm the validity of the distribution of low flow areas deep underground estimated based on the geophysical survey in FY 2020, as a part of an R&D supporting program titled "Research and development on Groundwater Flow Evaluation Technology in Bedrock" under contract to the Ministry of Economy, Trade and Industry (2021, 2022 FY, Grant Number: JPJ007597). The borehole name is Horonobe Fossil seawater Boring-1 and is referred to as HFB-1 borehole. HFB-1 is a vertical borehole drilled adjacent to the Horonobe Underground Research Laboratory (URL), which was drilled from the surface to a depth of 200 m in FY2021 and from a depth of 200 m to 500 m in FY2022. This report summarizes information related to the drilling of HFB-1 and various data (rock core description, geophysical logging, chemical analysis, etc.) obtained from the borehole investigation.

Evaluation of borehole siting for assessing the 3D distribution of paleo-saline water using collocated cokriging

Sato, Naomi; Hayano, Akira; Kashihara, Koji*; Teshima, Minoru*; Negi, Tateyuki*

no journal, , 

The objective of this study was to assess the effect of borehole siting on collocated cokriging (COK) for estimating the three-dimensional distribution of chloride ion concentration (Cl) and stable isotope (O, D) compositions of groundwater in the Horonobe area, which are indicators of paleo-saline water. When compared to the full model consisting of ten borehole surveys, COK with a partial dataset consisting of 1-3 borehole surveys covering the entire range of resistivity from the electromagnetic survey in the study area performed better than other datasets. The results suggested that a borehole survey at a site with the representative geochemical feature in the region could yield adequate coefficients in the COK and, as a result, produce reasonable estimates with a cost-effective procedure. This survey was funded by the Ministry of Environment, Trade and Industry.