Erdal Safak 1993 Methods alternative to spectral ratios are introduced to characterize site amplification. The methods are developed by using a range of models, from the simple constant amplification model to the time-varying filter model. Examples are given for each model by using a pair of rock- and soil-site recordings from the Loma Prieta earthquake. application/pdf en Publ by ASCE New methods to characterize site amplification text