Sites for Leg 192 were selected on the basis of multichannel seismic (MCS), single-channel seismic (SCS), bathymetric, and sonobuoy data collected during several surveys aboard Japanese and United States ships, in addition to satellite-derived gravity data (Fig. F2). The type and quality of seismic site-survey data vary (see Table T1 for a summary of seismic parameters). One survey (Thomas Washington 88-11) was undertaken before the availability of full Global Positioning System (GPS) coverage and thus has less reliable navigation data.
Japanese, American, and Norwegian scientists aboard the Hakuho Maru (KH98-1 Leg 2) acquired ~315 km of 24-channel and ~1795 km of 48-channel seismic reflection data, together with sonobuoy, bathymetric, gravity, and magnetic data, over the Ontong Java Plateau and Nauru Basin in 1998 (Mochizuki et al., 1998; Araki et al., 1998). Portions of the KH98-1 Leg 2 MCS data were used to locate the primary and alternate OJ-3 (central high plateau crest), OJ-6 (eastern salient), OJ-11 (eastern flank of the central plateau), and OJ-12 (eastern slope of the central plateau) sites.
Japan's site survey aboard the Hakuho Maru was conducted by the Ocean Research Institute of the University of Tokyo (Principal Investigator/Chief Scientist Asahiko Taira), in collaboration with the Japan Marine Science and Technology Center (JAMSTEC); Chiba University; the Institute for Geophysics, the University of Texas at Austin (MCS data processing); the Department of Geology, University of Oslo, Norway; the Department of Geology and Geophysics, University of Hawaii at Manoa; Graduate School of Oceanography, the University of Rhode Island; and the Department of Earth Sciences, University of North Carolina, Wilmington. Financial support for U.S. scientist involvement was provided by the U.S. National Science Foundation (OCE-9714368; Principal Investigator Millard F. Coffin) and the U.S. Science Support Program (USSSP) of the Joint Oceanographic Institutions (JOI), Inc.
American and Japanese scientists aboard the Maurice Ewing (cruise EW95-11) examined the southwestern flank of the plateau in 1995, collecting ~2000 km of coincident 120-channel seismic reflection, bathymetric, gravity, and magnetic data (Mann et al., 1996; Phinney et al., 1999). The OJ-7 primary and alternate sites (Stewart Arch) are located on an EW95-11 MCS line. However, lack of necessary clearances to drill in the Exclusive Economic Zone of the Solomon Islands prevented drilling of any sites using the EW95-11 MCS data.
The Maurice Ewing geophysical program was funded by the U.S. National Science Foundation (OCE-9301608; Principal Investigators/Chief Scientists Paul Mann, Millard F. Coffin, and Thomas H. Shipley), in cooperation with the Ocean Research Institute, University of Tokyo (Principal Investigator/Chief Scientist Kiyoshi Suyehiro), and Chiba University (Principal Investigator Masanao Shinohara).
As part of ODP site surveys for Leg 130 in 1988, scientists aboard the Thomas Washington (cruise TW88-11) acquired ~1500 km of digital SCS, bathymetry, gravity, and magnetic data on the Ontong Java Plateau. ODP Sites 803, 804, 805, and 806 were located using the cruise TW88-11 SCS data (Mayer et al., 1991; Mosher et al., 1993). The OJ-14 site (at the foot of the eastern flank of the central plateau) also was located using the TW88-11 SCS data.
Support for the Thomas Washington work was provided by the U.S. Office of Naval Research (n00014-91-1213) and the U.S. National Science Foundation (Principal Investigator Edward L. Winterer), in collaboration with the Canadian Secretariat for the Ocean Drilling Program, the Canadian National Scientific and Engineering Research Council, Dalhousie University, and the Département de Géologie Dynamique, Université Pierre et Marie Curie.