论文标题

观察站点选择物理模型参数估计对过程驱动的地震波场重建

Observation Site Selection for Physical Model Parameter Estimation toward Process-Driven Seismic Wavefield Reconstruction

论文作者

Nakai, Kumi, Nagata, Takayuki, Yamada, Keigo, Saito, Yuji, Nonomura, Taku, Kano, Masayuki, Ito, Shin-ichi, Nagao, Hiromichi

论文摘要

``大''地震数据不仅是通过地震仪获得的,而且还通过在智能手机中安装的建筑物,基础架构和加速度计中安装的激光仪获得的肯定会在不久的将来用于地震研究。由于在计算成本方面使用所有地震大数据是不切实际的,因此可以根据目的选择观察站点的方法是必不可少的。我们提出了一种通过过程驱动的方法准确重建地震波场的观察地点选择方法。所提出的方法选择适合准确估算物理模型参数(例如地下结构和源信息)的观察位点,以输入地震波场的数值模拟中。地震波场是通过数值模拟使用基于所观察到的观测位点估计的参数来重建的,该参数是根据所提出的方法选择的。提出的方法中的观察位点的选择基于每个观察地点候选物理模型参数的敏感性。与灵敏度相对应的矩阵是通过基于模拟计算衍生物来构建的,然后通过评估基于d-oftimative矩阵的数量来选择观察位点,以实验的最佳设计中提出的d-oftimalition标准。在本研究中,通过研究灵敏度矩阵的特征,获得了对参数敏感性(例如地震速度,层厚度和低中心位置)的敏感性的物理知识。此外,通过使用该方法选择的观测位点验证地震波场重建的准确性,显示了所提出方法的有效性。

The ``big'' seismic data not only acquired by seismometers but also acquired by vibrometers installed in buildings and infrastructure and accelerometers installed in smartphones will be certainly utilized for seismic research in the near future. Since it is impractical to utilize all the seismic big data in terms of the computational cost, methods which can select observation sites depending on the purpose are indispensable. We propose an observation site selection method for the accurate reconstruction of the seismic wavefield by process-driven approaches. The proposed method selects observation sites suitable for accurately estimating physical model parameters such as subsurface structures and source information to be input into a numerical simulation of the seismic wavefield. The seismic wavefield is reconstructed by the numerical simulation using the parameters estimated based on the observed signals at only observation sites selected by the proposed method. The observation site selection in the proposed method is based on the sensitivity of each observation site candidate to the physical model parameters; the matrix corresponding to the sensitivity is constructed by approximately calculating the derivatives based on the simulations, and then, observation sites are selected by evaluating the quantity of the sensitivity matrix based on the D-optimality criterion proposed in the optimal design of experiments. In the present study, physical knowledge on the sensitivity to the parameters such as seismic velocity, layer thickness, and hypocenter location was obtained by investigating the characteristics of the sensitivity matrix. Furthermore, the effectiveness of the proposed method was shown by verifying the accuracy of seismic wavefield reconstruction using the observation sites selected by the proposed method.

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