The surveys are being conducted at the Kurikoma national park in Akita prefecture and the Amemasudake area in Hokkaido, the companies said in a statement today.
The partners will continue the study through November, according to the statement. The companies plan to drill more exploratory wells at both sites until March 2016 before deciding whether to move on to the next phase of the study.
The next stage includes the drilling of production pilot wells, tests for steam production and hot water re-injection, the companies said in the statement.