西部山区大量城镇处于滑坡-泥石流等灾害链的危害范围内，因而山区城镇的安全和灾害风险值得重点关注。以甘肃省舟曲县立节镇立节沟滑坡-泥石流灾害链为例，在实地考察和遥感分析的基础上，基于合成孔径雷达干涉测量（interferometric synthetic aperture radar, InSAR）技术对地表形变进行分析并确定灾害链物源，利用RAMMS软件进行泥石流过程和危险性分析，并进一步进行易损性和风险评价。研究结果表明：①流域内主要沉降范围位于立节沟上方北山滑坡的古滑坡区边缘及顶部等区域，形变主要原因为土体的季节性冻融；②依据形变结果与遥感影像分析，并利用RAMMS动力模型对立节沟泥石流在1%、2%和5% 3种降雨频率下进行危险性分析，综合评价结果表明高危险区面积占比为70.51%，大量分布于北山滑坡松散堆积面、沟道及沟道两岸和沟口堆积扇处；③基于危险性和易损性评价结果，立节沟泥石流高风险区面积占比为13.10%，主要分布于沟口及沟道两旁建筑处；④立节沟上方滑坡松散堆积体体积庞大，仍处于持续蠕动-变形-滑动的过程中，为泥石流的汇流提供大量物源，不同降雨频率下的风险分区结果为城镇泥石流风险减灾提供参考。

A large number of towns in the western mountainous areas are within the hazard range of disaster chains such as landslides and debris flows, making the safety and disaster risk of mountain towns a key focus. The landslide-debris flow disaster chain in Lijie Gully, Lijie Town, Zhouqu County, Gansu Province was taken as a case study. Based on field investigations and remote sensing analysis, surface deformation was analyzed using interferometric synthetic aperture radar (InSAR) technology to determine the source of the disaster chain. The RAMMS dynamic model was then employed for the process and risk analysis of debris flows, followed by vulnerability and risk assessment. The research results indicate these as follows. The main subsidence areas within the basin are located at the edge and top of the ancient landslide area above Lijie Gully on the North Mountain, with the main cause of deformation being the seasonal freezing and thawing of soil. Based on the deformation results and remote sensing image analysis, the RAMMS dynamic model is used to conduct risk analysis of the Lijie Gully debris flow under three rainfall frequencies of 1%, 2%, and 5%. The comprehensive evaluation results show that the high-risk area accounts for 70.51%, largely distributed in the loose accumulation surface of the North Mountain landslide, the gully, both banks of the gully, and the accumulation fan at the gully mouth. Based on the risk and vulnerability assessment results, the high-risk area of the Lijie Gully debris flow accounts for 13.10%, mainly distributed in the gully mouth and along both sides of the gully where buildings are located. The large volume of loose accumulation above Lijie Gully is still in a continuous process of creeping-deformation-sliding, providing a large amount of material source for debris flows. The risk zoning results under different rainfall frequencies provide a reference for the disaster reduction of urban debris flows.