Towards national risk-targeted seismic hazard maps for mainland China

The global adoption of risk-targeted hazard models as the basis for seismic design has significantly increased over the past decade. In contrast, the current Chinese National Seismic Design Code relies on a uniform hazard map, which does not ensure uniform risk level across the region. This study aimed to introduce a risk-targeted probabilistic model for seismic design mapping in mainland China. Initially, well-founded hazard curves were plotted based on the probabilistic model of the fifth-generation ground motion zoning map. The study examined methods for integrating regional variations in hazard to achieve a uniform target risk across the region. The analysis revealed that the collapse risk for typical buildings under uniform ground motion varied across different areas of mainland China. By adopting reasonable values for the free input parameters, the generated maps were found to be broadly consistent with those currently in use. Additionally, the ratio of ground motion corresponding to a uniform collapse risk to the peak ground acceleration with a 10% probability of exceedance in 50 years (referred to as the risk coefficient) was mapped. A strong correlation was found between the risk coefficient and the slope of the seismic hazard curve.