HR: 1340h
AN: S23A-1099    [Abstracts]
TI: Development of Real-time Seismic Cable System
AU: * Takahashi, H
EM: h-takahashi@occ.ne.jp
AF: OCC Corporation, 2-3-5, Minato-Mirai, Nishi-ku, Yokohama, 220-6215, Japan
AU: Asakawa, E
EM: asakawa@jgi.co.jp
AF: JGI, Inc., 1-5-21, Otsuka, Bunkyo-ku, Tokyo, 112-0012, Japan
AU: Kawai, Y
EM: yuji.kawai@nipponsalvage.co.jp
AF: THE NIPPON SALVAGE CO., LTD., 1-5-1, Ohmorikita, Ohta-ku, Tokyo, 143-0016, Japan
AU: Ogasawara, Y
EM: ogasawar@k-kcs.co.jp
AF: KOKUSAI CABLE SHIP CO., LTD., Shinagawa East One Tower, 2-16-1,Konan, Minato-ku, Tokyo, 108-0075, Japan
AU: Saeki, T
EM: saeki-tatsuo@jogmec.go.jp
AF: Japan Oil, Gas and Metals National Corporation, 1-2-2 Hamada, Mihama-ku, Chiba, 261- 0025, Japan
AB: RSCS (Real-time seismic Cable System) is a new real-time seafloor reflection seismic observation system. It is a series of 3-component geophones and telemetry opto-electronics equipped into a high pressure resistant housing, which enables real-time seismic data acquisition at ultra deep sea. The first reflection seismic survey was carried out in March 2006. The geophone data show the high quality with the advantage such as precise timing with GPS link on board and superior sensor directivity. It is worthwhile for P- S converted wave processing as well as for P-P processing. The data processing is different from the conventional reflection seismic such as CDP method in the viewpoint of its geometry and P-S conversion. Precise velocity analysis and prestack migration solve the problem of its elevation difference between shot (sea surface) and receiver (sea bottom) point. The second seismic survey has been carried out in December 2006, equipped with accelerometer and hydrophone. These data was also very high quality as same as the geophone data. The accelerometer implies that the geophone will be replaceable with accelerometer. It means that there is a possibility to reduce the sensor size without gimbals mechanism. The hydrophone data is similar to the geophone data except the polarity change. This characteristic enables us to separate upgoing reflection from downgoing wave which includes only direct water waves and multiple reflections. The total data quality so far is very good compared to the conventional OBS systems. The RSCS has a great potential as a seabed observation system at deep sea.
DE: 7294 Seismic instruments and networks (0935, 3025)
SC: Seismology [S]
MN: 2007 Fall Meeting