The "Temperature limit of the Deep Biosphere off Muroto (T-Limit) " project required drilling and coring up to 1200 m below sea floor. This was to achieve the goal of investigating the sub-seafloor biosphere off Cape Muroto, where there is a geothermal gradient over 100℃/km, in the Nankai Trough.
An LTBMS was installed into the borehole, which had an estimated max temperature of 120℃ at the bottom, to examine the relationship between temperature and the biosphere limits. The key target of this LTBMS was to measure borehole temperature distribution in a high temperature environment.
- Developed miniature temperature loggers that can operate in high temperature (120℃) and high pressure (80MPa) environments underwater.
- Developed tough and heat resistant temperature sensors that are available in borehole with various external forces.
- Successful installation of the LTBMS in Nov. 2016.