New model of hazard potential index based on slope land disturbance and regional carrying capacity: a case study of Namaxia District in Kaohsiung City, Taiwan

In the last few decades, the economic activities have been growing fast in slope land of Taiwan. To investigate the effect of slope disturbance by slope utilization on the landslide potential, this study employed the concepts of regional carrying capacity, natural environment, and slope utilization to establish a hazard potential index based on slope land disturbance (I_HSD) to define the extent of slope development and utilization. Furthermore, combined with the product of the effective accumulated rainfall (EAR) and the maximum 3-h rolling rainfall intensity (I_3Rmax), logistic regression was used to establish a landslide potential model. The results revealed that the landslide grid ratio had a tendency to increase as the I_HSD interval value increased, when the I_HSD value reached approximately 350 and the rainfall index EAR × I_3Rmax exceeded 20,000 (mm²/3 h), landslide probability was high. Moreover, the overall accuracy of the landslide probability assessment model that was established using I_HSD combined with rainfall indicators was approximately 78%. As the average rainfall index of each rainfall event increased, the number of historical disaster points located in such areas also generally increased.