【摘要】 选取2003年1月至2011年12月宁夏及邻区发生的201个ML2.0以上地震事件进行反演,用经验格林函数计算得到本区地震震源谱衰减模型。在已知非弹性衰减系数和场地响应的条件下,计算得到震源谱并研究了近震震级与拐角频率、地震矩、震源破裂半径及应力降之间的关系。详细分析了震源参数误差大小及各种误差影响因素。对剩余应力降时空演化特征分析研究结果表明:高剩余应力降集中分布在宁夏北部宁蒙交界地区、低剩余应力降分布在宁夏中部同心、中卫一带,银川盆地中南部的吴灵地区和宁夏南部海原断裂带中东段剩余应力降变化较为明显,在时间分布上这两个区域剩余应力降在中强地震前均有降低—增强的趋势。更多还原

【Abstract】 201 events of ML≥2.0 are selected from January 2003 to December 2011 in Ningxia and its adjacent areas for inversion.Seismic spectral attenuation models are calculated by empirical Green function.On the base of known inelastic attenuation coefficient and site response,the source spectra are calculated and the relationship between local magnitude and corner frequency,seismic moments,rupture radius and stress drop are studied.Magnitude of error of seismic source parameters and influence factors are analyzed in detail.Temporal evolution characteristics of residual stress drop analysis results show that high residual stress drop is concentrated in the northern Ningxia and Inner Mongolia border region,low in Tongxin and Zhongwei area of central Ningxia.Residual stress drop changes more obviously in the Wuling area of south-central Yinchuan basin and middle-east Haiyuan fault of southern Ningxia.On these two regions,residual stress drops have decrease-enhancement trend in temporal distribution before strong earthquakes.更多还原