Application of a relief-optimized method for target space exteriorization sampling in landslide susceptibility assessment

Selection of negative samples significantly influences landslide susceptibility assessment, especially when establishing the relationship between landslides and environmental factors in regions with complex geological conditions. Traditional sampling strategies commonly used in landslide susceptibility models can lead to a misrepresentation of the distribution of negative samples, causing a deviation from actual geological conditions. This, in turn, negatively affects the discriminative ability and generalization performance of the models. To address this issue, we propose a novel approach for selecting negative samples to enhance the quality of machine learning models. We choose the Liangshan Yi Autonomous Prefecture, located in southwestern Sichuan, China, as the case study. This area, characterized by complex terrain, frequent tectonic activities, and steep slope erosion, experiences recurrent landslides, making it an ideal setting for validating our proposed method. We calculate the contribution values of environmental factors using the relief algorithm to construct the feature space, apply the Target Space Exteriorization Sampling (TSES) method to select negative samples, calculate landslide probability values by Random Forest (RF) modeling, and then create regional landslide susceptibility maps. We evaluate the performance of the RF model optimized by the Environmental Factor Selection-based TSES (EFSTSES) method using standard performance metrics. The results indicated that the model achieved an accuracy (ACC) of 0.962, precision (PRE) of 0.961, and an area under the curve (AUC) of 0.962. These findings demonstrate that the EFSTSES-based model effectively mitigates the negative sample imbalance issue, enhances the differentiation between landslide and non-landslide samples, and reduces misclassification, particularly in geologically complex areas. These improvements offer valuable insights for disaster prevention, land use planning, and risk mitigation strategies.