[S-CG71] [EJ] Ocean Floor Geoscience

[SCG71-18] Challenge to monitor the nearby hydrological response to the drilling into hydrothermal venting area: A case for mid-Okinawa Trough Noho hydrothermal site

*Masataka Kinoshita^1,2, Yuka Masaki², Wataru Tanikawa², Yohei Hamada², Tatsuo Nozaki², Hidenori Kumagai², Hiroyuki Yamamoto² (1.Earthquake Research Institute, University of Tokyo, 2.JAMSTEC)

Keywords:heat flow, Okinawa Trough, hydrothermal circulation

Thermal and hydrological properties within a hydrothermal system are obviously key factors to constrain the size, flux and lifetime of a hydrothermal reservoir. During the Expedition 908 conducted with JAMSTEC drilling platform Chikyu , heat flow and pressure monitorin were carried out using SAHF (Stand Alone Heat Flow meter) and POODLE (Pressure and "Ondo” On Deep-seafloor for Long-term monitoring Equipment). The main purpose of these observatories is to detect, if any, a thermal and hydrological response to the nearby drilling into a hydrothermal ventins site. Such signals should provide critical information about thermal and hydrological properties in a system. We deployed SAHF and POODLE 7 hours before drilling SIP NH-01(site C9017) and recovered them in November 2016 by using the ROV.

We present here a quick-look report on the monitoring of sub-seafloor temperature and pressure data, recorded in the period of nearby drilling into the Noho hydrothermal venting area in mid-Okinawa Trough.