Site conditions and earthquake ground motion - A review

Studies of the effects of local site conditions on the amplitudes and duration of strong earthquake ground motion have evolved from observations of earthquake damage to buildings. Such studies have involved different degrees of detail and sophistication in how scaling parameters are defined and used. We review the frequently used scaling parameters with an emphasis on the volume of site geology and site soil they represent, the assumptions of one-, two-, or three-dimensional modeling of the associated wave motions, and a linear versus nonlinear site response. We describe the limitations of using only one site parameter, based on the soil properties in the top 30 m, and discuss how the description of site effects could be refined by increasing the number of descriptive parameters and the extent to which those describe deeper geologic structure.