Combined with the precipitation forecast based on the NCFP GFS model on July 31, 2025 and multi-source data such as lithology, DEM and hydrological conditions along the Karakoram Highway, the TRIGRS model was adopted to conduct the landslide risk assessment in the northern area that was greatly affected by rainfall. The NCEP GFS precipitation forecast indicates that on July 31st, the rainfall along the Karakoram Highway will be relatively low, mainly concentrated in the southern region in terms of spatial distribution, with less rainfall in the northern mountainous areas. At this time, the infiltration of rainfall further increases the pore water pressure of the slope body, significantly reducing the effective stress and shear strength, and is prone to form a local saturated weak layer. These factors will cause the slope to rapidly evolve from the critical stable state to the instability threshold in the TRIGRS model, and the triggering probability of shallow collapses, slides or small debris flows will increase significantly.
The assessment results show (Figure 2) that the extremely high and highly prone areas are mainly distributed in a band-like pattern along the main river valley corridors in the north, concentrated in mountainous areas with significant terrain undulations and deep rivers, especially in the sections around Chilas and Gilgit and north of Gulmit. These areas generally have steep slopes and high-density steep slopes, and the foot of the slope is close to major rivers and transportation arteries. Locally, they form clusters of high-risk values for landslides, constituting the core area of the landslide risk pattern in the northern region. In contrast, although the southern region experienced a stronger rainfall process during the concentrated rainfall period (multiple rainfages within five consecutive days), the overall susceptibility to landslides was still mainly at a medium level, with scattered spatial distribution and a patchy pattern. This difference may be related to the extensive glacier coverage in the area south of Chilas. The lagging response of glaciers to rainfall runoff and their impact on surface stability may, to a certain extent, suppress the rapid and concentrated manifestation of landslide risks. Overall, although the total amount of rainfall in the southern region was greater, the spatial range of extremely high and highly susceptible areas did not show a significant expansion. In the northern region, despite relatively low rainfall, the distribution of high-risk areas for landslides remains relatively stable, controlled by complex terrain and dense river valley networks, and the coverage area has not undergone significant changes.
From the results of susceptibility, it can be seen that the sections along the KKH such as the Chilas-Gilgit section and the section north of Gulmit, which are highly prone to occurrence, should be regarded as key risk areas. Special attention should be paid to disasters such as high and steep cutting slopes and mudslides during and after rainfall.
结合 2025 年 7 月 31日基于 NCFPGFS 模式的降水预报与喀喇昆仑公路沿线的岩性、DEM、水文条件等多源数据，采用TRIGRS模型，对受降雨影响较大的北部地区展开滑坡危险性评估。NCEPGFS降水预报显示，7 月 31日喀喇昆仑公路沿线降雨量较少，在空间分布上主要集中于南部地区，北部山区降雨较少，此时降雨入渗进一步提高了坡体孔隙水压力，显著降低了有效应力与抗剪强度，容易形成局部饱和薄弱层。这些因素在 TRIGRS模型中将使边坡从临界稳定状态快速向失稳阈值演化，浅层崩塌、滑塌或小型泥石流的触发概率大幅上升。
评估结果表明（图2），极高及高易发区主要沿北部主要河谷走廊呈带状分布，集中出现在地形起伏显著、河流深切的山地地带，尤以 Chilas、Gilgit 周边及 Gulmit 以北路段最为典型。这些区域普遍存在陡峭坡面、高密度陡坡，且坡脚邻近主要河流与交通干线，局部形成滑坡高风险值的聚集区，构成了北部地区滑坡风险格局的核心区域。相较之下，南部区域虽在降雨集中期内经历了更强的降雨过程（连续5天内多次降雨），但整体滑坡易发性仍以中等等级为主，空间分布零散，呈现斑块状格局。此差异可能与 Chilas 以南地区广泛分布的冰川覆盖有关，冰川对降雨径流的滞后响应及其对地表稳定性的影响可能在一定程度上抑制了滑坡风险的快速集中表现。总体而言，尽管南部区域降雨总量更大，但极高及高易发区的空间范围未出现明显扩展；而北部地区在降雨量相对较小的情况下，受控于复杂地形与密集河谷网络，滑坡高易发区分布仍保持相对稳定，覆盖范围亦未发生明显变化。
从易发性结果可以看出，沿 KKH 穿越的Chilas-Gilgit路段 、Gulmit以北段等高易发性路段应被视为重点风险区段，需重点关注在降雨过程中与雨后的高陡切坡、泥石流等灾害。
