Relationships between natural terrain landslide magnitudes and triggering rainfall based on a large landslide inventory in Hong Kong
Citation
Gao, L., Zhang, L.M., Cheung, R.W.M. (2018). Relationships between natural terrain landslide magnitudes and triggering rainfall based on a large landslide inventory in Hong Kong. Landslides, 15: 727-740. Link to paper
Abstract
Rain-induced landslides are recognized as catastrophic hazards on steep terrain, yet hazard studies often emphasize initiation thresholds without quantifying likely landslide magnitudes. Using the Enhanced Natural Terrain Landslide Inventory (ENTLI) with 19,763 records in Hong Kong, this study established magnitude-frequency relationships for open hillslope landslides and channelized debris flows in terms of number, scar area, volume, and density. Empirical correlations were derived between landslide magnitude metrics and maximum rolling rainfall intensities over multiple durations. Results show that maximum rolling 4- to 24-hour rainfall better predicts landslide magnitude than 1-hour rainfall alone. The paper also proposes intensity-duration thresholds for different magnitude levels and reports initiation thresholds of 75, 90, 100, 120, 150, 180, and 200 mm for rolling 1-, 2-, 4-, 6-, 8-, 12-, and 24-hour rainfall, respectively.