The most adopted definition of landslide hazard combines spatial information about landslide location (susceptibility), threat (intensity), and frequency (return period). Only the first two elements are usually considered and estimated when working over vast areas. Even then, separate models constitute the standard, with frequency being rarely investigated. Frequency and intensity are intertwined and depend on each other because larger events occur less frequently and vice versa. However, due to the lack of multi-temporal inventories and joint statistical models, modelling such properties via a unified hazard model has always been challenging and has yet to be attempted. Here, we develop a unified model to estimate landslide hazard at the slope unit level to address such gaps. We employed deep learning, combined with a model motivated by extreme-value theory to analyse an inventory of 30 years of observed rainfall-triggered landslides in Nepal and assess landslide hazard for multiple return periods. We also use our model to further explore landslide hazard for the same return periods under different climate change scenarios up to the end of the century. Our results show that the proposed model performs excellently and can be used to model landslide hazard in a unified manner. Geomorphologically, we find that under both climate change scenarios (SSP245 and SSP885), landslide hazard is likely to increase up to two times on average in the lower Himalayan regions while remaining the same in the middle Himalayan region whilst decreasing slightly in the upper Himalayan region areas.

本研究通过深度学习和极值理论模型，使用观测降雨诱发滑坡的30年清单数据，以及不同气候变化情景下多个回程期的数据，开发了一个统一模型来估计山体滑坡的灾害风险，结果显示该模型性能优异，能够以统一的方式建模滑坡灾害风险。在地貌上，我们发现在两个气候变化情景（SSP245和SSP885）下，喜马拉雅山脉下部地区的山体滑坡风险平均增加了两倍，中部地区保持不变，而上部地区略有减少。

深度学习与极值统计交叉路口：定义滑坡灾害的规范化