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
Q m 4—Q al 4 soft soil layer
Alluvial marine sedimentation
Quaternary soft soil layer