Empirical Near-Source Attenuation Relationships for Horizontal and Vertical Components of Peak Ground Acceleration, Peak Ground Velocity, and Pseudo-Absolute Acceleration Response Spectra

Near-field horizontal and vertical earthquake ground motions

“…[7] is probably due to the large number of weak ground motions in the records used. The new equation predicts similar horizontal PGA to those predicted by the equations of Boore et al [9] and Campbell [14] reflecting the large number of records from large magnitudes and short distances in their sets. The new equation predicts slightly larger horizontal PGA than the equation of Spudich et al [28] for extensional regimes, again confirming the finding of Spudich et al [28] that the strong ground motion in extensional regimes is smaller than that in other tectonic regimes.…”

“…This can be seen in Figure 2 because the predicted PGAs for all three local site conditions are almost identical (because the site coefficients are small) whereas the predicted PGAs using the equations of Boore et al [9], Ambraseys et al [7] and Spudich et al [28] for different local site conditions vary significantly (because the site coefficients are much larger). The site dependence is also lower than that predicted by the equation of Campbell [14] which allows for site amplifications which are dependent on magnitude and distance. The negligible dependence of near-field horizontal PGA on site conditions shows, as pointed out by Faccioli and Reseńdiz [19], that close to the source, site conditions are less important in determining ground motions than source and path.…”

“…The magnitude dependence however, is almost identical to that in the equations of Boore et al [9] and Spudich et al [28] showing that these equations can be used for ground motion estimation in the near-field. The magnitude dependence of the new equation is larger than that of the equation of Campbell [14] possibly due to the form of the equation adopted by Campbell [14] which allows for distance saturation or because of the distance measure used by Campbell [14] (seismogenic distance) differs from that used here (distance to the surface projection of the rupture plane).…”

“…In this article, the estimated ground motions using the equations derived in this study are compared with estimated ground motions using the equations from some commonly cited studies, Boore et al [9], Campbell and Bozorgnia [15], Ambraseys et al [7], Ambraseys and Simpson [5], Campbell [14], Chapman [16] and Spudich et al [28]. As in this study, the comparisons studies mainly use strong-motion records from active tectonic regions, therefore the estimated ground motions from this study and the comparison studies can be directly compared.…”

“…Campbell [14] showing that the attenuation mechanism that is dominant in the nearfield cannot be determined. This can be seen in Figure 2 because the new curves are almost parallel to the curves derived in the other studies.…”