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Development of Vertical Cable Seismic System
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 74th EAGE Conference and Exhibition incorporating EUROPEC 2012, Jun 2012, cp-293-00299
- ISBN: 978-90-73834-27-9
Abstract
The vertical cable seismic is one of the reflection seismic methods. It uses hydrophone arrays vertically moored from the seafloor to record acoustic waves generated by surface, deep-towed or ocean bottom sources. Analyzing the reflections from the sub-seabed, we could look into the subsurface structure. Because the VCS is an efficient high-resolution 3D seismic survey method for a spatially-bounded area, we proposed it for the hydrothermal deposit survey tool development program by Japanese government. Our first experiment of the VCS surveys has been carried out in Lake Biwa, JAPAN in 2009 for a feasibility study. Prestack depth migration is applied to 3D data to obtain good quality 3D depth volume. Based on the results, we have developed four autonomous recording VCS systems. After a trial experiment, we carried out several survey cruises for hydrothermal deposit in Okinawa Trough. Through the data acquisition, we could confirm that our VCS system works well even in the severe circumstances around hydrothermal deposits. We have, however, also confirmed that the uncertainty in the positions of the source and the hydrophones could lower the quality of subsurface image. It is necessary to develop a total survey system that assures an accurate positioning and deployment techniques.