JAMSTEC

Center for Deep Earth Exploration (CDEX)

menu
HOME > Technology Development > LTBMS(Long Term Borehole Monitoring System) > JFAST Observatory

JFAST Observatory

CDEX installed a temporary LTBMS for the Japan Trench Fast Drilling Project (JFAST). This was to measure the residual heat signature from the friction caused by the slip during the huge earthquake and tsunami of the 11 March 2011 Tohoku-oki mega-earthquake.

The JFAST Expedition had two main goals: collect geophysical data and core samples from the earthquake slip zone or fault, and deploy the LTBMS to measure the residual frictional heat produced by the earthquake.

CDEX helped develop the LTBMS measuring temperature, deployed in water 6897.5 m deep, installed in a borehole 854.8 m below the sea floor. This project successfully deployed and recovered the LTBMS, holding temperature data, including data from across the fault.

Results

  • Summary of the JFAST project (above fig.) and LTBMS re-entry (right photo).

    Summary of the JFAST project (above fig.) and LTBMS re-entry (right photo).

  • LTBMS for JFAST and on board assembling work (July 2012)

    LTBMS for JFAST and on board assembling work (July 2012)

  • KAIKO7000II recovering the LTBMS (April 2013). Scientists marked the wellhead with the message "WASURENAI 3.11" (Never forget 3.11).

    JKAIKO7000II recovering the LTBMS (April 2013). Scientists marked the wellhead with the message "WASURENAI 3.11" (Never forget 3.11).

  • Subseafloor residual temperature field. A) Time/space map of data >650 mbsf. B) Depth profile of residual temperature from 29 October 2012 (Fluton et al., 2013).

    Subseafloor residual temperature field. A) Time/space map of data >650 mbsf. B) Depth profile of residual temperature from 29 October 2012 (Fluton et al., 2013).

to top