摘要
采用Ω平方模型来约束中小地震的震源位移振幅谱,从而实现对震源参数、介质的几何扩散特征、介质的非弹性衰减以及场地响应等参数的同时反演,数值模拟结果表明该方法是可靠的。江苏省苏南地区的几何扩散较好地符合三段衰减统计模型,该地区的品质因子与频率的依赖关系以频率3.0Hz为界分为低频、高频二部分,且均符合指数衰减关系,而全部频率点的品质因子频率依赖关系似乎与四元素流变模型的Q值理论频率特征曲线比较一致。该地区中小地震地震矩对数值与震级ML具有较好的线性关系;地震矩与拐角频率呈现出良好的双对数关系,且该地区的地震应力降与震源半径之间的关系在震源半径小于300m时与圆盘静态破裂模式理论关系较吻合。
By using Ω-square model restrain the source displacement amplitude spectrum of moderate-small earthquakes, the authors developed a simultaneous inversion method of site response, source parameters, geometrical attenuation factors and inelastic attenuation of medium. Numerical simulation shows that this inversion method is reliable. In the southern area of Jiangsu Province, the geometrical attenuation factors preferably accord with the statistical model of three segments attenuation, and the relation between the quality factor and frequency in this area is divided into two sects, one is high frequency segment that the frequency is more than 3.0 Hz and the other is low frequency segment, and the relation between two sects obeys the exponential law, but in the all frequencies, the relation seemly accords with the rheologic model of four elements. The relation between logarithmic moment and magnitude M_L accords with linear relation. The relation between the moment and corner frequency takes on double logarithmic law. When the source radius is smaller than 300 m, the relation between the stress drop and source radius tallies with the theoretical law of the disk static rupture model.
出处
《地震》
CSCD
北大核心
2004年第4期27-36,共10页
Earthquake
基金
地震联合基金课题(104047)
中国地震局分析预报中心地震图像与数字化地震观测资料应用实验室资助
关键词
震源参数
介质衰减
场地响应
同时反演
Source parameters
Medium attenuation
Site response
Simultaneous inversion
