Response spectrum modelling for rock sites in low and moderate seismicity regions combining velocity, displacement and acceleration predictions

Abstract

SUMMARYSeismic hazard modelling for regions of low and moderate seismicity is often hampered by the lack of indigenous strong motion data. Thus, empirical attenuation models developed for analogous &data rich' seismic regions have typically been used as the basis for de"ning the ground motion attenuation properties of the subject region. Alternatively, limited data recorded from small tremors, or aftershocks, have been used to extrapolate the attenuation relationships of potentially destructive but infrequent, large magnitude events. However, as explained and demonstrated in this paper, both approaches are prone to error in the absence of a rational and viable analytical framework to support their application. Addressing this, the methodology introduced herein combines the component attenuation model (CAM) (developed in the companion paper (Earthquake Engng Struct. Dyn. 2000; 29:1457}1489) with observations on local isolated earthquake events, to determine representative design response spectra for both force-and displacementbased seismic applications.In CAM, the acceleration and displacement response spectra may be constructed very conveniently, and with reasonable accuracy, using simpli"ed expressions for the spectrum corner periods and the response spectral velocity parameter, for regions of di!erent geological conditions. The comparison of the response spectra determined by CAM with similar response spectra described by numerous well known empirical models (derived in data rich high seismicity regions) provide very useful indications of the credibility and advantages, as well as the limitations, of CAM. The implied increasing stress drop with increasing moment magnitude is a signi"cant observation from the comparative study.

S wave inelastic attenuation and site effect in the northern Tianshan area

“…The Fourier amplitude spectrum of horizontal ground motion of stochastic method can be expressed as follows (Lam et al, 2000).…”

Prediction of response spectral parameters for Bhuj earthquake (26th January 2001) using a component attenuation modelling technique

“…CAM is the modified version of the stochastic simulation method which incorporate wave attenuation model developed by Boore [7]; it takes into account various effects that a wave undergoes during its travel from source to site to predict a Design Response Spectrum for direct use of engineering applications, Chandler and Lam [8], Lam and Wilson [9], Chandler et al [10] and Lam and Wilson [11]. The intrinsic philosophy of CAM is not new, as similar methodology was adopted by Newmark and Hall [12] to develop normalized response spectral model, based on the strong motion observations of Californian earthquakes.…”

Artificial Accelerograms Representative of the Damage Distribution on a Low-Rise Shear Wall

“…Two main fundamentally different modelling strategies can be distinguished. The first modelring strategy consists of modelling all the phenomena during an earthquake, including the fault rupture mechanism at the seismic source and the seismic wave propagation through the soil [Lam et al, 2000;Boore et al, 19861. The second modelling strategy is more orientated towards the computation of the response of a structure submitted to an earthquake excitation.…”