Southwest Indian Ridge (SWIR) is a typical ultra-slow spreading ridge which has been extensively studied based on geophysical survey, geochemical sampling and morphological feature extraction. In this paper, based on the high-resolution multibeam bathymetric data, we extract seven types of topography, including fault, axial rift, axial volcanic ridge (AVR), axial trough, AVR's remnant, volcanic cone and oceanic core complex (OCC). We perform quantitative morphotectonic statistic, verifying the relations between the topography and magmato-tectonic mechanism of SWIR 49–50°E. The analyzed results of flank topography show that the average seafloor depth of the southern flank is shallower than that of the northern flank. The Total Cumulative Length of the faults in the northern and southern flank is 624.6 km and 948.2 km. The number, Total density, Average Length and Maximum Length of the faults in the southern flank are higher than those in the northern flank. An OCC and detachment faults locate in the southern flank. The asymmetry in flank topography indicates the asymmetric spreading mode of the study area. The analyzed results of the axial topography show that AVRs and troughs develop in the rift. The rift is narrower and shallower in the AVR regions, and wider and deeper in the trough regions. These observations support the partition of magmatic and less-magmatic stretching in the study area, and indicate the relation between the variation of rift's depth-width and the magmato-tectonic accretion.

西南印第安海岭（SWIR）是典型的超慢扩散海岭，已在地球物理调查，地球化学采样和形态特征提取的基础上进行了广泛研究。本文基于高分辨率的多波束测深数据，提取了七种类型的地形，包括断层，轴向裂谷，轴向火山脊（AVR），轴向槽，AVR的残余，火山锥和大洋核心复合体（OCC）。我们进行定量的构造构造统计，验证了SWIR 49–50°E的地形与岩浆构造机制之间的关系。侧面地形的分析结果表明，南部侧面的平均海底深度要比北部侧面的浅。北部和南部侧面断层的总累积长度分别为624.6 km和948.2 km。数量，总密度，南部侧面断层的平均长度和最大长度高于北部侧面。OCC和分离断层位于南部侧面。侧面地形的不对称性表明研究区域的不对称扩展方式。轴向形貌的分析结果表明，裂谷发育了AVR和谷。在AVR地区，裂谷较窄而较浅，在低谷区域则较宽且较深。这些观察结果支持了研究区域内岩浆和低岩浆伸展的划分，并表​​明了裂谷的深度宽度变化与岩浆构造增生之间的关系。侧面地形的不对称性表明研究区域的不对称扩展方式。轴向形貌的分析结果表明，裂谷发育了AVR和谷。在AVR地区，裂谷较窄而较浅，在低谷区域则较宽且较深。这些观察结果支持了研究区域内岩浆和低岩浆伸展的划分，并表​​明了裂谷的深度宽度变化与岩浆构造增生之间的关系。侧面地形的不对称性表明研究区域的不对称扩展方式。轴向形貌的分析结果表明，裂谷发育了AVR和谷。在AVR地区，裂谷较窄而较浅，在低谷区域则较宽且较深。这些观察结果支持了研究区域内岩浆和低岩浆伸展的划分，并表​​明了裂谷的深度宽度变化与岩浆构造增生之间的关系。