THE SEISMIC RISK ASSESSMENT AND SEISMIC ZONING OF HONG KONH REGION

The Hong Kong Kowloon Block which have been uplifted continually and stable since late Cretaceous Paleogene period is identified and determined as a potential source with maximum credible magnitude M=5.5, while the late Cretaceous Paleogene fault basins which are located around the Hong Kong Kowloon Block are determinated as potential source with maximum credible magnitude more or equal 6.0 based on the characteristics of seismo geology tectonic activities in the Hong Kong and its adjacent regions. The attenuation law of peak ground acceleration (PGA) and standard response spectra of acceleration () with damping 5% underlain by rock ground were determined by comparing Chinese continent with Westen of USA in the similarity of tectonic environment of continental earthquaks, potential source with credible seismic magnitude 5.0～7.5, and considering ground motion saturation at near source. The near source attenuation model of acceleration and response spectrum also reflect the field of Intensity distribution in East China and the dimension of source faulting in Chinese continent. The seismic hazard analysis and calculating of bedrock ground motion were completed by considering the ground motion attenuation model with near source saturation and using ordinary method of seismic hazard analysis based on Poisson probability model for the Hong Kong region. In this paper the seismic design parameters underlain by rock ground and its zoning which contain peak ground acceleration and acceleration response spectra with annual exceedance probability level p= 0.02, 0.002 and 0.0004 are also was given. The seismic parameters and the corresponding zoning maps could be satisfied for the two level seismic design of many engineering structures.