Influence of local soil and geologic site conditions on pseudo relative velocity spectrum amplitudes of recorded strong motion accelerations, 1987

It is well recognized now that the soil and geologic site conditions modify the amplitudes and the duration of incident strong earthquake waves (Kanai, 1949,1957; Gutenberg, 1957; Duke, 1958; Medvedev, 1955; Tsai, 1969). This has been studied empirically (e.g. Trifunac 1971a,b; 1976a,b,c; 1978, 1979, 1980; Trifunac and Anderson 1977, 1978; Trifunac and Brady 1975a,b,c; Trifunac and Lee, 1978, 1979, 1987a,b; Trifunac and Udwadia, 1974; Trifuanc and Westenno, 1977, 1982; Udwadia and Trifunac, 1973 and Westenno and Trifunac, 1978) and theoretically (e.g. Moeen-Vaziri and Trifunac, 1987a,b; Trifunac, 1971, 1973; Wong and Trifunac, 1974 and Wong, et al. 1976). The overall effects of both soil and geological site conditions have been synthesized recently by Trifunac (1987).; One of the first studies which analyzed the effects of local soil conditions on the changes of the shape of the response spectrum has been carried out by Zhou (1965). This was followed by Seed et al. (1974, 1976), who analyzed. this effect quantitatively, by comparing the average spectrum shapes for four different classifications of the soil characteristics at the recording sites. The effects of the geological site characteristics were investigated by Gutenberg (1957) and by Trifunac (1976c).; The purpose of this report is to present an extension of the work of Trifunac (1987) to the scaling of the Pseudo Relative Velocity Spectra. Since the format of this work will follow closely that of Trifunac (1987), the reader may wish to peruse his results before proceeding to read this report. Furthermore, the reader will find many sections of this report to be repetitive in the format, style and details, as the reading progresses from Parts I into Parts II, III, IV and V. For completeness in presentation many equations and many plots have been repeated from one part of this work to the next. It was felt, however, that after the proper selection of the scaling models is done, some fine points, particularly some minor inconsistencies among different models might be "forgotten." Thus, every effort has been made to document all results, and to present all details as graphically as possible. The casual reader may wish, to glance over the end results, and to read the summary in Section V as well as the conclusions. The rest of this report should serve as a pictorial archive summary on the properties of our regression models for scaling the Pseudo Relative Velocity (PSV) response spectra, and may be helpful for the formulation of better regression models in future analyses.