摘要：南海的擴張、成因演化研究的成果主要基于深部速度研究及磁條帶研究的基礎上,但南海東北部邊界的研究相對薄弱.本次通過對南海東北部邊界的反射地震剖面973的綜合研究,結合前人的天然地震震源研究及地質研究成果,得到南海形成與擴張是單方向向菲律賓呂宋島弧-臺灣島地塊漂移的結果.南海各塊體處于一個統一的區域應力場作用之下,菲律賓呂宋島弧-臺灣島地塊限制了南海的擴張與發展;在此應力條件下,不同部位受力狀態不同,就南海東北部973剖面地震波場特征,可劃分為五個構造單元:AB段南海東北部大陸架張性盆地區;BC段大陸坡為伸展區,形成大量張性盆地;CD段中部深海沉積盆地為弱擠壓區,深海沉積盆地弱變形,大陸坡張性盆地淺俯沖其下,深海沉積盆地西部翹起,向東傾斜;DE段東部為強擠壓區,沉積盆地擠壓變形,越向東擠壓越強烈,深海沉積盆地淺俯沖其下,相對弱變形并西部翹起;E以東,菲律賓呂宋島弧-臺灣島構造帶為穩定地塊.南海東北部在東或南東方向統一的區域應力場作用下,處于張性、弱擠壓、強擠壓不同壓力狀態,形成南海特有的由北西向東呈現拉張-弱擠壓-強擠壓構造格局,反射地震削面上顯示兩個淺俯沖點.每個塊體構造層呈手風琴風箱式折曲并向東聚斂,近菲律賓呂宋島弧-臺灣島構造帶其折曲更為嚴重,沉積盆地由西向東,展現為不同階段的沉積盆地,發育、成長、結束、消亡,塊體俯沖方向以及各塊體的區域性傾伏方向均與區域應力場方向一致.%In this research,a comprehensive study of the 973 seismic profiles was conducted. Combined with previous studies of the geological and natural hypocenter,we proposed that the formation and expansion of the South China Sea is the result of the one-way drift to the Philippines Island of Luzon arc-Taiwan terrain. All the blocks of South China Sea are under the same regional stress field and its expansion and evolution were constrained by the Philippines island of Luzon arc-Taiwan terrain. Based on the stress conditions,and the characteristics of seismic wave field,five structural sections were distinguished in the 973 seismic profile of the northeastern South China Sea:AB section is a stretching area of the continental shelf;BC section is the expanded area of the continental slope,with many pull-apart basins;CD section is the deep sedimentary basin with weak compression and deformation. The extensional basins of the continental slope subducted underneath this section shallowly. The western deep-sea sedimentary basins was elevated,and inclined eastward; DE section is a strongly compressed sedimentary basin zone with stronger squeezing in the eastern part. The weak-deformed deep-sea sedimentary basins subducted shallowly underneath this section,and were lifted up in the western region. The east of E is the tectonic belt of Luzon-Taiwan island arc,and is a steady rigidity block. Under the eastern or southeastern uniform stress field,the northeastern part of the South China Sea underwent different stress state and formed unique structure patterns in South China Sea:extensional-weak compressive-strong compressive from north-west to east. Two shallow subduction zones were recognized in the seismic profiles. All the tectonic blocks have accordion-folds-style structures and converged in the east,with stronger folding near the Philippine island of Luzon arc-Taiwan Island. From west to east sedimentary basins showed different stages of the basins development:growth,mature and terminations. Block subduction and regional block inclining directions were all aligned with the directions of the regional stress field.