A novel approach to probabilistic seismic landslide hazard mapping using Monte Carlo simulations

As a potential destructive secondary hazard initiated by earthquakes, earthquake-triggered landslides can cause significant losses. Seismic landslide hazard maps are important for land use planning and landslide hazard reduction in tectonically active areas. A comprehensive probabilistic seismic landslide hazard mapping approach incorporating the uncertainties of slope properties and displacement prediction is required to promote the application of hazard maps. Based on the definition of the critical slope angle, this paper proposes an alternative seismic landslide hazard category considering the uncertainty of geotechnical properties of soil using Monte Carlo simulations and incorporating the ground motion variability based on the displacement hazard curve. The proposed new hazard category is applied to the region of Anchorage, Alaska, for the seismic landslide hazard mapping process. Subsequently, parameter analyses are performed to explore the sensitivity among the factors that contributed to the seismic landslide hazard map. The results of seismic landslide hazard maps show that the area of hazardous zone of most geologic units in present study is smaller than that in the deterministic analysis. Comparing with the probabilistic method using logic tree analysis, the proposed approach using Monte Carlo simulations predicts different landslide hazardous zone due to the probabilistic distribution of geotechnical properties of soil. The predicted hazardous zone is also sensitive to the resolution of the digital elevation model and different coefficient of variation combinations.