Vertical Cable Seismic (VCS) Survey for Seafloor Massive Sulphide (SMS) Exploration

The VCS survey is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by seismic sources. Because the VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed it for the SMS survey tool development program started by Japanese government. In 2010, we manufactured the autonomous VCS data acquisition systems. Through several experimental surveys, our VCS is successfully completed.

In 2011 and 2013, we have carried out VCS surveys using GI gun and high-voltage sparker in the Izena Cauldron, which is one of the most promising SMS areas around Japan. But no seismic surveys have been conducted there because seismic is not proven to be effective for SMS exploration so far. The VCS data have been processed with VSP-CDP Mapping and Migration. By the survey with GI gun, we obtained a 3D PSDM volume which gives the large-scale information of the hydrothermal system. By using high-voltage sparker, significantly high resolution images were obtained. We can recognize reflections related to SMS. These survey results gave useful information to geologists and we can conclude VCS is a promising survey tool for the SMS exploration.