用随机有限断层方法模拟2016-11-13新西兰Mw7.8地震

在未来大地震发震构造已知的前提下，提出用经验公式确定大地震断层长度、宽度、地震矩和滑动分布等参数，并用随机有限断层方法预测未来大地震。用随机有限断层方法模拟2016-11-13新西兰M_W7.8地震的12个基岩台站地震动时程和反应谱，并用模拟的频谱幅值与记录频谱幅值平均比值确定模拟误差。结果表明，在周期为0~10 s的范围内，模拟误差在0.92~1.08之间，不同频率模拟误差的标准差变化范围不超过1。95%的置信区间宽度随频率无明显变化，模拟结果反映了地震动记录的平均效果。用准随机方法重新获取新西兰大地震断层初始破裂点和位错滑动分布，模拟地震动并计算模拟误差随频率的变化，得到与最初模型相似的结论，从而进一步证实了本文提出的获取震源参数并用随机有限断层方法预测未来大地震的可靠性，且其特别适用于大地震远场模拟。

Simulation of Amberley New Zealand November 13, 2016 MW7.8 Earthquake Using Stochastic Finite Fault Method

Drawing on the known seismogenic structures of future large earthquakes, we propose to use empirical formulas to determine the parameters of length, width, seismic moment and sliding distribution of the large earthquake faults, and use the random finite fault method to predict future large earthquakes. Considering the M_W7.8 earthquake that occurred in New Zealand on November 13, 2016, the ground motion time history and response spectrum of 12 bedrock stations, are simulated by stochastic finite fault method. The simulation error is determined by the average ratio of the simulated spectrum amplitude to the recorded spectrum amplitude. The results show that the period is in the range of 0-10 s and the simulation error is between 0.92-1.08. The standard deviation of the simulated error of different frequencies is not more than 1, and the width of 95% confidence interval has not changed significantly with the frequency. The simulation results reflect the average effect of ground motion records. Although a specific simulation may differ greatly from records, for engineering purposes we are interested in whether the simulation results are equivalent to the average results of seismic records. The quasi-random method is used to retrieve the initial rupture point and dislocation slip distribution of the New Zealand earthquake fault, simulate the ground motion, calculate the variation of simulation error with frequency, and obtain conclusions similar to those of the original model. This further confirms our proposed method of obtaining the seismic source parameters and the use of stochastic finite fault methods for the prediction of future large earthquakes is reliable, especially for the far-field simulation of large earthquakes.