Landslide Hazard Assessments of A Potential Earthquake-triggered in Central Taiwan Using Newmark's Model with the Stochastic Semi-Empirical Technique

Abstract

This research aims to evaluate the probability distribution of landslides triggered by a potential earthquake. Based on the evaluations, successive disaster prevention and mitigation can be well-prepared in advance. Deriving the critical acceleration value depends on the geometry and strength of the material on the slope. Thus, the Newmark's displacement of slope can be determined using the critical acceleration and strong motion recording of an earthquake. A threshold value of Newmark's displacement is assumed as 5cm, which means a landslide may occur if Newmark's displacement is greater than it. To identify the feasibility, we synthesize two waveforms of the 1999 Chi-Chi earthquake (M_w 7.6) and one for the 2013 Nantou earthquake (M_w 6.2) to compute the Newmark's displacements at Jiou-Jiou Peaks and Shinyi town in Nantou County, Taiwan by using the stochastic semi-empirical technique. The Newmark's displacements are 9.75 averaged and 6cm respectively, which are coincident with the earthquake-triggered landslides occurring actually. By counting accumulations of Coulomb's stress changes of Nantou earthquakes in 2013 in central Taiwan, we predict the epicenter of a potential earthquake. The regression relation between critical acceleration with Arias intensity of the seismic waveform is employed to calculate Newmark's displacements in the Nontou County. Accompanied by Newmark's displacement, the empirical probabilities of earthquake-induced landslides are derived. Accordingly, there are four populated densely areas with higher Newmark's displacements and probabilities, indicating that high landslide risk is existing potentially in these areas and the corresponding disaster prevention management and mitigation must be carefully regulated.