GEODETIC DATA INVERSION USING A BAYESIAN INFORMATION CRITERION FOR SPATIAL-DISTRIBUTION OF FAULT SLIP
GEODETIC DATA INVERSION USING A BAYESIAN INFORMATION CRITERION FOR SPATIAL-DISTRIBUTION OF FAULT SLIP
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DOI：
10.1111/j.1365-246x.1992.tb00102.x
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发表时间：
1992-05-01
影响因子：
2.8
通讯作者：
MATSUURA, M
中科院分区：
文献类型：
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作者：
YABUKI, T;MATSUURA, M
我们开发了一种新的反演方法，使用 Akaike 贝叶斯信息准则 (ABIC) 从大地测量数据重建震源静态图像。同震表面位移通常通过线性积分方程与断层表面上的滑移分布相关。通过有限数量的已知基函数对断层滑移分布进行参数展开，产生一组以简单矢量形式表示的观测方程。将滑移分布平滑度的先验约束与观测方程结合起来，我们构建了具有未知超参数的贝叶斯模型。控制贝叶斯模型结构的超参数的最佳值是使用 ABIC 根据观测数据客观确定的。一旦确定了超参数的值，我们就可以使用最大似然法来寻找断层滑移的最优分布。我们通过使用具有随机噪声的理论数据的数值实验检验了该方法的有效性。我们使用这种方法分析了与 1946 年南海道地震 (M(s) = 8.2) 相关的大地测量数据。结果表明，本次地震的断层滑动分布有4、6 m两个主峰，分别位于纪伊半岛和室户岬附近。这两个高滑移区被沿着纪伊海峡延伸的低滑移区明显分开。这样的滑移分布与本次地震西部地区的破裂过程与东部地区明显不同的事实相对应。
We developed a new inversion method to reconstruct static images of seismic sources from geodetic data, using Akaike's Bayesian Information Criterion (ABIC). Coseismic surface displacements are generally related with a slip distribution on a fault surface by linear integral equations. Parametric expansion of the fault slip distribution by a finite number of known basis functions yields a set of observation equations expressed in a simple vector form. Incorporating prior constraints on the smoothness of slip distribution with the observation equations, we construct a Bayesian model with unknown hyperparameters. The optimal values of the hyperparameters, which control the structure of the Bayesian model, are objectively determined from observed data by using ABIC. Once the values of hyperparameters are determined, we can use the maximum likelihood method to find the optimal distribution of fault slip. We examined the validity of this method through a numerical experiment using theoretical data with random noise. We analysed geodetic data associated with the 1946 Nankaido earthquake (M(s) = 8.2) by using this method. The result shows that the fault slip distribution of this earthquake has two main peaks of 4 and 6 m, located off Kii Peninsula and Muroto Promontory. These two high-slip areas are clearly separated by a low-slip zone extending along Kii Strait. Such a slip distribution corresponds with the fact that the rupture process of this earthquake in the western part is notably different from that in the eastern part.