双侧破裂模型对地震动空间相关性影响的远场分析

Far-field analysis of effects of bilateral rupture fault on space correlation of strong ground motion

根据震源理论，将由双侧破裂模型计算得到的场地Ｆｏｕｒｉｅｒ谱，等价表述为从初始破裂点沿两个相反方向破裂的单侧破裂模型独立计算得到的相同场地Ｆｏｕｒｉｅｒ谱，以相对长度为权重的线性组合。据此，在远场假定下，得到了双侧破裂模型刻画地震动场分布的两个重要复交参数α１和α２，以及由它们确定场的孔径的解析表达式．最后，以一次地震为例，计算了α１和α２的实部和虚部，以及孔径随震中距、方位角和频率变化的三维图像。

On the assumption that seismic source is simplified as bilateral rupture fault with finite length, this paper qualitatively studies the seismic source effects on space correlation of strong ground motion. Based on seismic source theory, this paper shows that the Fourier spectra of strong ground motion at the site caused by a bilateral rupture fault can be equivalent to a linear combination of the Fourier spectra caused by two independent single-lateral faults with opposite rupture direction with relative rupture length as weight number.