Seismic Hazard Determination for the Coastal Region of South China I: Generic Crustal Modelling
Nelson Lam,Adrian Chandler,John Wilson, and Graham Hutchinson
The objective of this paper is to describe and illustrate a rational seismological modelling approach for developing design earthquake response spectra for application in a moderate seismicity region. In the first stage a seismicity model is developed, using the Coastal Region of South China (CRSC) as an example. Combining this with a generic source model and an assumed generic crustal model, the ground motion parameters (representing acceleration,velocity and displacement properties) have been determined. Importantly, the generic crustal model is assumed to have properties which are identical to the continental shield region of Eastern North America (ENA). Subsequently, response spectrum modelling procedures are described and applied to the example region, to determine design-level spectral for rock sites. The response spectra predicted by theseismological model were found to be very consistent with current code provisions, and with design spectra proposed by other researchers, in the velocity-controlled medium period range. However, significant discrepancies have been identified in other period ranges. The ground motion parameters and response spectra derived in this study were based on the generic ENA crustal conditions. The effects which the regional crustal properties and the crustal thickness have upon the ground motion parameters have been described in the second part of the paper.