有限单元法在首都圈地区跨断层水准测量监测能力初步评价中的应用

以首都圈地区布设在不同断层上的24处跨断层水准观测为研究对象, 建立了地壳分层结构、 含不同倾角断层的三维有限元模型, 模拟计算了断层倾角和走向对跨断层水准观测结果的影响, 并结合跨断层水准测量资料、 震例研究及R值预测评分, 对首都圈地区跨断层水准测量监测能力进行了初步评价。 结果表明: ① 跨断层水准观测能力一定程度上受倾角和走向因素的共同影响; ② 跨断层水准布设于倾角30°~70°且走向与地面水平最大位移方向近垂直时具有较好的映震效能; ③ 首都圈跨断层水准监测体系总体而言具备较强的监测能力。

Application of 3D Finite Element Numerical Simulation in Preliminary Evaluation of Cross-fault Leveling Monitoring Capacity in the Capital Area

With the purpose of establishing more effective cross-fault leveling station, we established three-dimensional finite element models that involve different fault angles and vertical inhomogeneity to study the impact patterns of fault dip and strike on cross-fault leveling monitoring, using the twenty-four cross-fault leveling stations scattered over different faults in the capital area as research objects. Based on cross-leveling data analysis, earthquake case study, and R-value assessment, we carried out preliminary evaluation of cross-fault level monitoring effectiveness in capital area. Result from finite element modeling, earthquake case study, R-value assessment show that: ① the monitoring effectiveness of cross-fault leveling are affected by both fault dip and strike; ② the station located across fault with dip between 30°~70° and strike perpendicular to crustal general motion has relatively stronger monitoring effectiveness in terms of earthquake prediction; ③ the cross-fault leveling in the capital area possesses satisfactory monitoring capacity in general.