Long-offset Multi-Channel Seismic

Long-offset Multi-Channel Seismic (LMCS) System
In 2015, first Large-offset Multi-Channel Seismic (LMCS) system was operated by Taiwan Ocean Research Institute (TORI), NARLabs. In 2018, LMCS system, including G. Gun array with volume of 1,060 in3 (maximum volume of 3,200 in3) and 1.5-km-long (maximum of 6 km long) streamer, is built successfully on R/V Legend to collect a high-quality seismic data offshore SW Taiwan. In 2019, we also cooperated with National Central University to discover seamount Legend of South China Sea in the maiden cruise of R/V Legend. This LMCS system will be a new power of marine geophysical exploration for surveying natural resources (ex. petroleum and gas hydrate etc.) and geologic hazards (ex. faults, earthquake potential structures and landslide etc.) offshore Taiwan in future. For linking New Southbound Policy of Taiwan government, we hope that TORI will cooperate with island nations south of Taiwan (ex. Philippine and Indonesia etc.) to explore the South China Sea (SCS) and west Pacific. It will not only upgrade the security for avoiding marine geologic hazards from the SCS and west Pacific but also enhance the relationship between these island nations and Taiwan. There are three major equipment of LMCS system:
  • Seismic Source System:
  • A new type of air gun (G. Gun II) is light and easy to be disassembled, maintained and operated in a cruise. There are 16 air guns with volume of 150 and 250 cube inches. Therefore, data quality of seismic signals will be improved by mixing volumes of gun array.
  • Seismic Data Collecting System:
  • A solid streamer (maximum of 6 km long), made by SERCEL, was used to collect with 480 channels. Furthermore, the quality of seismic data will be controlled by SERCEL Seal system.
  • Navigation System:
  • The positions of air-gun array, birds and tail buoy will be monitored by SERCEL navigation system and SEAMAP tracking system. Thus, all information of the LMCS equiment is imported to a server of navigation system. Then, it will calculate the locations of the equipment and shooting points to shoot by distance and overcome the unstable sea situation offshore Taiwan. Also, the P1 and P2 format of navigation data can be outputted.
    Figure1、LMCS system on R/V Legend.
    Figure2、LMCS system on R/V Legend was used for marine experiment. (1) Seismic source system: Air-gun array undersea. (2) Seismic data collecting system: Streamer and winch. (3) Navigation system: Computer system in the control room.
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