四川及邻区地震动衰减关系

SEISMIC MOTION ATTENUATION RELATIONS IN SICHUAN AND ADJACENT AREAS

根据地震构造环境和震害分布特点,将四川及邻区划分为西南地区和四川盆地地区.收集了西南地区96次、四川盆地地区40次近代破坏性地震资料,并对各次地震的震级参数进行了统一校核.按照该地区震中烈度与震级、有感半径与震级的统计关系,对地震烈度衰减进行了近场与远场特征控制,建立了地震烈度沿长轴、短轴和平均轴的衰减关系.统一了中国与美国面波震级的震级标度,利用最新得出的美国西部基岩水平向地震加速度反应谱衰减关系,采用考虑地震加速度的近场距离饱和与震级饱和特征的衰减模型,转换得到了该地区的基岩水平向地震加速度反应谱衰减关系.

The Sichuan and adjacent areas is divided into southwest China region （SWCR） and Sichuan Basin region （SCBR） according to tectonic backgrounds and seismic damage distribution features. 96 modern destructive earthquakes in SWCR and 40 in SCBR are gathered respectively. All their magnitude parameters are checked. Based on the statistic relations between epicentral intensity and magnitude as well as relation between sensible radius and magnitude, the near and far field seismic intensity attenuation features are represented and controlled. And then the seismic intensity attenuation relations along major axis, minor axis and mean axis are established separately. The systematic deviations of surface wave magnitude between China seismograph network and U.S. seismograph network are considered in this paper. By making use of the new attenuation relations of bedrock horizontal ground acceleration response spectrum in west U. S. , the attenuation relations of bedrock horizontal ground acceleration response spectrum in SWCR and SCBR are digital transformed based on the attenuation model considering acceleration saturation of distance and magnitude in near field.