# Effect of Characteristics of Ground Motion on Seismically Induced Sliding Surface of Slopes
## 1 Introduction  
Catastrophic hazards produced by seismically induced slope failures have been widely observed in previous severe earthquakes [1, 2]. Therefore, a reliable prediction of the seismic performance of slopes is essential. Assessing the stability of the slope has been a difficult task for engineers because the factors controlling the dynamic response and failure mechanism of the slope are not yet fully understood. A wide range of approaches is available to predict the seismic stability of the natural and engineered slopes (e.g., dams and embankments). These include (a) pseudo-static method; (b) Newmark sliding block method; (c) stress deformation methods. The pseudo-static approach is the simplest and most widely used design method for the calculation of the factor of safety [3, 4, 5]. The pseudo-static method is recommended in many codes and design guidelines for conventional projects. However, the pseudo-static approach has been reported to have inherent drawbacks, which include the assumption of a rigid perfectly plastic behavior of soil and uncertainty in approximating the transient nature of earthquake loading as an equivalent force utilizing a horizontal seismic coefficient, \(k\), which represents the lateral acceleration normalized by the gravitational acceleration. The second most practiced design concept was presented by [PERSON] [6], which is termed as the Newmark sliding block model. In this method, the soil mass above the failure surface is assumed as a rigid block, which slides and produces a permanent displacement when yield acceleration (\(k_{y}\)) is exceeded. Many researchers have used the Newmark sliding blockconcept to calculate permanent downslope displacements. New equations and empirical charts were proposed to account for the effect of ground motion characteristics. [PERSON] (1978) proposed a regression model to estimate landslide displacement based on strong motion records. However, the model is only recommended for preliminary screening or regional scale hazard mapping. [PERSON] and [PERSON] [PERSON] and [PERSON] (2018) developed an empirical predictive model for predicting the earthquake induced displacements based on the Newmark sliding block procedure. In these studies, the soil mass was assumed as a rigid block. [PERSON] and [PERSON] [PERSON] and [PERSON] (2018) developed a unified predictive model to account for dynamic response of sliding mass. [PERSON] and [PERSON] [PERSON] and [PERSON] (2018) followed the same hypothesis and developed a displacement model for rigid and flexible slopes. In both pseudo-static and Newmark methods, it has been assumed that the critical sliding surface is independent on the frequency characteristics and amplitude of the input ground motion. The surface determined from a limit equilibrium analysis has been utilized. The dynamic analysis method has been used as an alternative procedure to evaluate the seismic performance of slopes [PERSON] et al. (2018); [PERSON] et al. (2018); [PERSON] et al. (2018). However, it should be noted that a majority of the studies still use the Newmark sliding block framework to extract the Newmark displacement. In this procedure, the stresses acting on a predefined failure surface are integrated to determine equivalent acceleration time history along the surface. It is used along with \(k_{y}\) to determine the Newmark displacement. Therefore, in a dynamic analysis, the definition of a predefined failure surface is necessary. [PERSON] et al. [PERSON] et al. (2018) performed a series of finite difference (FD) analysis to calculate the earthquake-induced displacements in mountain slopes. The sliding surfaces calculated from the limit equilibrium and FD analyses were revealed to be similar. It should be noted that the slopes considered were composed of thin soil layer over inclined bedrock, for which the variability of the sliding surface is constrained because of the limited depth of the layer.