Due to the absence of federal criteria, seismic design and performance criteria for mixed and hazardous waste landfills are generally developed on a project-specific basis, supplemented by state and project-specific standards. In developing project-specific criteria, the federal Subtitle D standards for seismic design of municipal solid waste landfills are often used as a minimum standard for mixed and hazardous waste facilities. Seismic performance standards are also usually developed on a project-specific basis, employing either a “withstand without harmful discharge” or a “withstand without damage” performance standard, depending on the certainty of continuing aftercare. Quantitative criteria established to demonstrate compliance with these performance standards should consider the inherent conservatism in the type of analysis employed to evaluate the selected performance measure. Material properties for seismic design of mixed or hazardous waste landfills are also usually developed on a project-specific basis. Material property values are often subject to considerable uncertainties about waste composition, variability in the waste composition, and waste heterogeneity. Parametric and sensitivity studies are generally used to compensate for the uncertainty in waste properties and the variability and heterogeneity of the waste. Four case histories are presented to illustrate these issues
