Seismic hazard and risk assessments for Beijing-Tianjin-Tangshan area,China

This paper attempts to analyze seismic hazard and risk in Beijing-Tianjin-Tangshan, China, area from 500-year intensity observations, and to provide the basic parameters or intensities for seismic design and other mitigation considerations.First, we digitized the intensity observations (maps) using ArcGIS with a cell size of 0.1 degree ×0.1 degree.Second, we performed a statistical analysis on the digitized intensity data and derived intensity-frequency relationship (hazard curve) for each cell.Finally, we estimated seismic risk in terms of a probability that intensity exceeds Ⅶ , Ⅷ, or Ⅸ in a certain periods (i.e., 50years) based on the assumption of a Poisson distribution for earthquake occurrence.We also estimated the corresponding intensity with 10 percent probability of exceedance in 50 years.The results shows that the area has high seismic risk and the current design requirement for the area may be not adequate.