【摘要】 基于《中国地震动参数区划图》(GB18306-2001)中的5套潜在震源区划分及地震活动性参数方案,计算了中国大陆地区所对应的50年超越概率10%和2%的基岩峰值加速度标准差和变异系数.分析了峰值加速度标准差和变异系数的空间分布特征,统计了省级、地级及县级城市峰值加速度的不确定性.结果表明,潜在震源区划分及地震活动性参数方案的不确定性对峰值加速度影响显著.标准差较大的地区与7.0级以上地震及大型活动断裂具有很强的相关性;峰值加速度变异系数较大的地区主要集中分布在我国的弱震活动地区,其次在塔克拉玛干沙漠及阿拉善高原地区.我国绝大部分城市峰值加速度标准差小于80×10-2m/s2;峰值加速度变异系数小于0.4.此外,经分析,峰值加速度的变异系数比标准差更适合表达区划图的不确定性.这些研究结果可为下一代区划图的编制工作提供一些有价值的参考.更多还原

【Abstract】 Based on the 5 schemes for potential seismic source delineation and seismicity parameter design presented in the National Seismic Zoning Map of China(GB 18306-2001),we calculated standard deviation and variation coefficient of peak ground acceleration(PGA) for 10-percent and 2-percent exceedance probability in 50 years at bedrock level on the Chinese mainland.The spatial distribution of standard deviation and variation coefficient of PGA is analyzed,and uncertainty of PGA for province-,prefecture-and county-level cities in China is also studied.The result shows that the uncertainty in the schemes for potential seismic source delineation and seismicity parameter design has a significant impact on peak ground acceleration.The areas with large standard deviation are closely related with earthquakes of magnitude 7.0 or greater and large-scale active faults,while the areas with large variation coefficient of PGA are mainly located in regions with weak seismicity,the Taklimakan desert in the west and the Alxa plateau.Standard deviation of PGA is lower than 80×10-2 m/s2,and variation coefficient is smaller than 0.4 in most cities in China.After analysis we found that,as compared with standard deviation,variation coefficient of PGA is more suitable for representing uncertainty in the zoning map.The results can provide valuable references for the compilation of next version of the zonation map.更多还原