Kenji Tara

Wide-area vertical cable seismic survey: Repeated deployment using ROV in Iheya North Knoll, Okinawa-Trough

Vertical cable seismic (VCS) system has been developed to provide higher resolution structure under the seafloor than conventional surface seismic reflection survey. We have applied the VCS to delineate the Seafloor Massive Sulfides (SMS) which has complex structure since 2009. According to past surveys around SMS area, we have already demonstrated that the VCS is useful to detect the subseafloor layer of SMS. High resolution profile of the subseafloor structure helps us to detect the SMS and evaluate its volume.

Vertical Cable Seismic (VCS) Survey for SMS exploration in Izena Cauldron, Okinawa-Trough

In 2014, the Japanese government started the Cross-ministerial Strategic Innovation Promotion Program (SIP), which includes ‘New-generation Offshore Exploration Techniques’ as an area of interest. We proposed the Vertical Cable Seismic (VCS) survey technique for this program, especially for the exploration of Seafloor Massive Sulfides (SMS). VCS is a reflection seismic method that uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by various acoustic sources. This method is useful to delineate detailed structures in a spatially-limited area below the seabed in the deep sea where conventional surface seismic is not effective. We have been developing an autonomous VCS system with the financial support of the Japanese government since 2009. We have carried out several VCS surveys and completed our VCS system.