中文摘要：

基于显式有限元方法和运动学震源模型并利用昆明盆地三维地下构造模型,本文研究了震源参数对断层附近长周期地震动的影响.结果表明,断层的破裂方式、埋藏深度、破裂速度以及断层面上位错的不均匀分布对断层附近长周期地震动有重要影响.不同破裂方式下,破裂的方向性强的区域分布不同,由于破裂的方向性效应和复杂场地条件的共同作用,导致不同破裂方式的断层附近地震动分布差别很大.随着破裂速度的增加,方向性效应更加明显,断层附近的长周期地震动也随之增大;对于浅源地震,随着断层埋深的增加,地震动明显下降.对于埋藏深度很浅的断层,当Asperity靠近断层上沿时,会显著增大其在地表投影附近的长周期地震动.能否合理地估计这些基本震源参数,是预测未来发震断层周围地震动场的关键.

英文摘要：

Using a 3-D structure model of Kunming basin, the effects of source parameters on long period ground motions are studied in this paper by the explicit finite element method and kinematic source model. The results show that the rupture mode, the rupture velocity, the fault depth and the distribution of the heterogeneous dislocations on the fault plane have great influence on near-fault long period ground motions. Different rupture mode can generate very different distribution of near-fault ground motion owing to the forwarddirectivity effect and the complex site conditions, since the areas with strong forward-directivity effect are very different in different rupture mode. As the rupture velocity increases, the forward-directivity effect become more obvious, and the long period ground motion increases. As the fault depth increases, the long period ground motions decrease rapidly. The long period ground motions will increase greatly as the asperity is located near the upper egde of the fault for very shallow earthquakes. So how to estimate these basic parameters reasonably is the most important problem for predication of near-fault strong ground motions.