Estimation of an ultra-high-temperature geothermal reservoir model in the Kakkonda geothermal field, northeastern Japan

•A supercritical geothermal reservoir was modeled under varying conditions integrating geophysical and well data.•The supercritical geothermal reservoir in Kakkonda, Japan, is at a depth of ≤ 4 km.•The center of the supercritical geothermal reservoir is likely within the Kakkonda granite.•The supercritical geothermal resources may exist about 2 km east of the WD-1a well. The probable locations of ultra-high-temperature geothermal reservoirs in the Kakkonda geothermal field were modeled under varying conditions using resistivity and temperature data. The results indicate that ultra-high-temperature geothermal reservoirs are likely present at elevations of ≥ –4000 m. The centers of these reservoirs, characterized by low-resistivity and high-permeability values, are approximately in the Kakkonda granite (0.09 ± 0.01 Ma). The area covered by the modeled reservoirs is consistent with estimates from other approaches, such as the microseismic event distribution. This study suggests that an ultra-high-temperature geothermal reservoir is present in the area.