中文摘要：

近十几年来，我国在南海琼东南陆坡区、西沙海槽区和神狐海域陆续开展了多个航次的天然气水合物资源调查工作。调查资料揭示南海西北陆坡海底滑坡较为发育。其成因复杂，因地形地貌、底质、沉积作用、构造活动的影响而发育规模不等、形态各异的滑坡带。利用近年来调查获得的高分辨率单道地震及多波束测深资料，在以往天然气水合物调查区内识别出3个滑坡带：神狐滑坡带、西沙海槽北坡滑坡带和琼东南陆坡滑坡带。神狐滑坡带位于神狐暗沙东南侧陆架坡折带，水深400--600m，长约100km，宽约25km，呈NE—sw向展布，其形成与天然气水合物分解密切相关，稳定性较好。西沙海槽北坡滑坡带位于西沙海槽北侧陆坡，水深约2000—3100m，长约90km，宽约15—20km，呈近EW走向，为巨厚沉积物在重力作用下发生整体性滑移，稳定性较好，但局部仍存在不稳定区域，极易发生滑坡扇。琼东南陆坡滑坡带位于琼东南陆坡陡坡处，水深约250--850m，呈NE—sw向展布，长约150km，宽约5—10km，其主要受活动断层及底流侵蚀影响，稳定性较差。本研究成果可为天然气水合物资源调查与勘探提供科学依据。

英文摘要：

Several cruises of gas hydrate resource survey have been carried out at Qiongdongnan continental slope, Xisha trough as well as Shenhu area since 1999. The geological data revealed that sub-marine slides were developed in the northwestern continental slope of the South China Sea. Three landslide zones were identified based on high-resolution single-channel seismic profiles and multi-beam echo sounding data. This paper discusses in detail the characters and formation mechanism of these landslide zones. Shenhu landslide zone is about 100 km long, 25km wide, and is oriented along the NE-SW direction at a water depth of 400-600m. It has close relationship with gas hydrate dissociation and stable geological engineering condition. Xisha trough northern slope landslide zone is about 90 km long, 15-20km wide, and has an EW trending at a water depth of 2000-3100m. It was formed by huge thickness sediment movement under process of gravity. Xisha trough slide has a better geological engineering condition, but its slide fan still can be seen in some unstable segments. Qiongdongnan continental slope landslide zone is about 150 km long, 5-10kin wide, and is oriented in a NE-SW direction at a water depth of 250-850m. It was affected by active faults and bottom current erosion, and has an unstable geological condition The results of this study can be a scientific base for gas hydrate survey and exploration.