Proceedings of the
9th International Symposium for Geotechnical Safety and Risk (ISGSR)
25 – 28 August 2025, Oslo, Norway
Editors: Zhongqiang Liu, Jian Dai and Kate Robinson

Rapid Assessment of Earthquake-Induced Landslide Counts

Shihao Xiao1,a, Limin Zhang1,2,b, Jian He1,c, Ruochen Jiang1,d, Xin He1,e and Yingyue Han1,f

1Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.

asxiaoai@connect.ust.hk

bcezhangl@ust.hk

cjhebl@connect.ust.hk

drjiangad@connect.ust.hk

exhebb@connect.ust.hk

fyhanbl@connect.ust.hk

2HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute, Futian, Shenzhen, China

ABSTRACT

Earthquake-induced landslides can lead to catastrophic consequences. Rapid assessments of such landslides provide first-order estimates of the spatial distribution of co-seismic landslides, informing emergency response and resource allocation. Existing methods for evaluating earthquake-induced landslides primarily focus on landslide susceptibility, which offers qualitative information rather than quantitative predictions.Susceptibility assessments are influenced by the sampling ratiosof landslide and non-landslide samples, yielding relativeprobabilities rather thanthe exactprobabilities of landsliding. Therefore, this study proposes a shift from qualitative (i.e., landslide susceptibility) to quantitative (i.e., landslide counts) assessments. Modelling landslide counts offers more detailed information than landslide susceptibility. The proposed methodenables the estimation of landslide counts and their spatial locations, paving the way for subsequent runout simulations and quantitative risk assessments.

Keywords: Landslides, Earthquakes, Zero-inflated Poisson distribution, Landslide risk, Spatial analysis.


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