Improvement of air gun array's width for a quasi-3D multi-channel seismic survey by single streamer cable

摘要

In order to understand the deep structure of the Earth's crust Japan Marine Science and Technology Center (JAMSTEC) has been conducting site surveys in the adjacent seas of Japan using a multi-channel seismic survey system (MCS). Nippon Marine Enterprises Ltd. (NME), which was established in 1980, operates four research vessels, a deep submersible Shinkai 2000 and three deep ROVs owned by JAMSTEC. In 1997, JAMSTEC contracted NME to operate the MCS and in 1999 one hundred ocean bottom seismometers (OBSs) were added. The R/V Kairei has installed on board an air-gun system, the largest in the world, with a 200-litre capacity, and 5000-metre long streamer cables to carry out the MCS reflection surveys. Each gun has a capacity of 4.6 litres and pressure of 140 kgf/cm/sup 2/ with a total of 8 guns. An air-gun system is expanded by two paravanes, one paravane is towed from the starboard side while another is towed from the port side.