مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

The significance of near-surface attenuation in bedrock, as distinct from attenuation in unconsolidated soft soil sediments, has been identified. The Kappa parameter, which characterizes the extent of this attenuation mechanism, is generally difficult to measure, particularly in regions of low and moderate seismicity. Empirical correlation of Kappa with the near-surface shear wave velocity parameter in rock has been developed using global information obtained from limited independent studies. The influence of shaking intensity on the value of Kappa has been found to be negligible in conditions that are consistent with the average seismicity of Australia (as also for other intraplate regions). Thus, adjustment in the value of Kappa to account for variations in earthquake magnitude, or the intensity of ground shaking, has not been recommended for intraplate conditions. In parallel with the empirical correlations, values of Kappa have also been obtained from calibration analyses employing stochastic simulations of the seismological model, along with onedimensional non-linear shear wave analyses ofthe rock layers. Good agreement in the values of Kappa obtained from the different approaches has been demonstrated. The correlation of Kappa with the near-surface shear wave velocity ofrock, as recommended in this paper, has thereby been reaffirmed.