Predicting earthquake-induced landslide displacements using Newmark's sliding block analysis

A principal cause of earthquake damage is landsliding, and the ability to predict earthquake-triggered landslide displacements is important for many types of seismic-hazard analysis and for the design of engineered slopes. Newmark's method for modeling a landslide as a rigid-plastic block sliding on an inclined plane provides a workable means of predicting approximate landslide displacements; this method yields much more useful information than pseudostatic analysis and is far more practical than finite-element modeling. Applying Newmark's method requires knowing the yield or critical acceleration of the landslide (above which permanent displacement occurs), which can be determined from the static factor of safety and from the landslide geometry. Earthquake acceleration-time histories can be selected to represent the shaking conditions of interest, and those parts of the record that lie above the critical acceleration are double integrated to determine the permanent landslide displacement. For approximate results, a simplified Newmark method can be used, which estimates Newmark displacement as a function of landslide critical acceleration and earthquake shaking intensity.