ISSN 0917-057X

The National Research Institute for Earth Science and Disaster Prevention (NIED) has drilled fourteen boreholes in Central Japan, twelve of which (excluding the boreholes at Ashio and Shingu) were drilled as part of the “Active Fault Zone Drilling Project”. Ashio borehole was drilled to examine the stress state, pore water pressure, and heat flow within a seismogenic region, while Shingu borehole was drilled to monitor temporal changes in in situ stress and strain and to reveal their accumulation processes in relation to a great inter-plate earthquake. In this note, we present geologic columns and geophysical logging data for the boreholes, including spontaneous potential, resistivity, sonic velocity, bulk density, neutron porosity, total gamma ray, spectro-gamma ray, caliper, and temperature. The geophysical data and columns are presented at a scale of 1/2900. We hope that the data included in this note will contribute to the analysis of the crustal structure of these regions