EPOLLS Model for Predicting Average Displacements on Lateral Spreads

A new empirical method, called the EPOLLS model, is developed for predicting ground surface displacements due to liquefaction-induced lateral spreading. Lateral spreading is defined as the mostly horizontal deformation of gently sloping ground as a result of soil liquefaction. In strong earthquakes, lateral spreads often cause considerable damage. The EPOLLS (Empirical Prediction Of Liquefaction-induced Lateral Spreading) model can be used to predict the average horizontal surface displacement that can occur on a potential lateral spread. The model is presented in three parts (designated as the Regional-EPOLLS, Site-EPOLLS, and GeotechnicalEPOLLS components) that allow for progressively better predictions with the addition of more site parameters. The model consists of simple algebraic equations with four to nine parameters that represent the seismic input, site topography, and subsurface conditions. The EPOLLS model was developed from a multiple linear regression analysis of data from 71 lateral spread case studies. The EPOLLS database, regression modeling, quality of the fit, and limitations on the use of the EPOLLS model are discussed.