福州盆地强地面运动特征的有限元数值模拟

Finite element analysis of seismic wave propagation characteristics in Fuzhou basin

区域性地震波强地面运动的量化数值模拟分析结果可以用来指导城市规划建设,并在防震减灾中发挥重要作用.本文采用有限元数值模拟方法来模拟由地震激发的区域地震波强地面运动过程,并得到地表峰值速度和加速度的分布特征.考虑到福州是东南沿海的重要省会城市,其明显的盆地结构特征使它很容易遭受强地震灾害的影响.因此本文以福州盆地为主要研究对象,假定盆地的主要断层某一位置在未来可能发生灾害性地震,则该地震会激发地震波的强地面运动,并由于地形、沉积层等主要影响,在盆地内部发生放大.通过对地震波传播过程的数值模拟和后处理分析,给出了该盆地的地表峰值位移、峰值速度和峰值加速度分布图谱.该图谱可为未来的福州城市规划和抗震减灾提供定量科学参考依据.

Quantitative results of numerical simulation on the strong ground motion triggered by the local earthquakes can be used to guide the urban planning and construction. It also plays an important role in the earthquake disaster assessment. We propose a finite element model to simulate the strong ground motion excited by local earthquake. Then the peak ground acceleration （PGA） as well as the peak ground velocities are calculated accordingly with the displacement distribution with the respect of time. Fuzhou is the capital city of Fujian province, which locates in the coastal area of southeast China. It is characterized by the conspicuous basin structures with major fault zones. It is very easy to be subjected to hazards from the local strong earthquakes. This makes Fuzhou as an ideal test-bed to investigate the behaviors of the strong ground motion triggered by the possible future earthquakes. By taking advantage of large-scale finite element simulation, the peak ground displacements, peak ground acceleration and peak ground velocity patterns are put forward by elaborately designed post-processing routines. These quantitative results can provide critical elements for the future urban planning, and future earthquake hazards prediction.