Orientation‐Dependent Prediction of Seismic Slope Displacement in Strike‐Slip Earthquakes

ABSTRACT The Newmark sliding‐block displacement ( D ) has been widely used to evaluate the seismic performance of slopes in both site‐specific and regional scales. Current predictive models for D of slopes are generally developed without consideration of the specific slope orientation. This study presents the directionality analysis of preferential polarization for D and a model to predict the D considering the specific slope orientation in strike‐slip earthquakes. Based on a database of 817 ground motion records with strike‐slip faulting, it is shown that the orientation of maximum D tends to occur close to the transverse orientation (perpendicular to the orientation at a given site pointing to the epicenter). There is a significantly larger probability of exceeding the median displacement ( D 50 ) over all orientations in the transverse orientation. The orientational D is strongly correlated with the angular difference with respect to the transverse orientation. The orientation‐dependent model is developed to estimate D at specific orientations by combining with an existing D 50 predictive relationship. The model enables the transformation of D 50 to D in any specific orientation, and hence allowing for the site‐specific and regional landslide hazard assessment with consideration of specific slope orientation in strike‐slip earthquakes.