冲绳海槽南部
the south of okinawa trough
southern okinawa trough
中国科学院南海海海洋研究所
South China Sea Institute of Oceanology
academia sinica
冲槽切气隙工艺
technology of cutting air space on punching slot
冲海积
Alluvial marine sedimentation
Q m 4—Q al 4 soft soil layer
Quaternary soft soil layer