Development and systematization of analytical methods for seismometer array records and expansion of seismometer array on campus

这项研究的目的是：(1)发展地震台阵记录的分析方法及其工程应用；(2)研究地面运动的空间特性；(3)为抗震设计提供时空地震动。(1)发展地震台阵记录的分析方法研究波的传播现象。从精度和数值稳定性的角度对这些方法进行了检验。然后，利用观测资料对方法进行了验证，并对非线性波在软土中的传播进行了讨论。这些结果发表在第11届欧洲地震工程、土壤动力学和地震工程会议论文集上。(1.b)利用地震检波器阵列的记录，研究了峰值地面加速度的空间变化。这项研究的结果在JSCE会议上进行了总结。(2)对地面运动的空间特征的调查在崎玉大学安装的地震仪阵列得到了扩展。对该系统的记录和其他已发表的记录进行了分析，以考察水平波的传播速度和相干值等地震动的空间特征。(3)为抗震设计提供时空地震动。对时空地震动的预测方法进行了检验和改进，以便更准确地反映实际的波传播。还发展了一种基于观测记录内插的新方法。对于不擅长波形分析的工程师来说，这种方法的数值稳定性已经得到了密切的研究。

The objectives of this study are (1) development of analytical methods for the records of seismometer array and their engineering application ; (2) investigation of the spatial characteristics of ground motions ; and (3) provision of space-time ground motions for earthquake resistant design.(1.a) Development of Analytical Methods for the Records of Seismometer ArraysNew methods both in time domain and frequency domain have been developed to investigate the phenomena of wave propagation. The methods have been examined from the viewpoints of precision and numerical stability. Then, the methods have been demonstrated by using observation records, and the nonliear wave propagation in soft soil has been discussed. These results were published in the proceedings of the 11th European Conference on Earthquake Engineering and Soil Dynamics and Earthquake Engineering.(1.b) Spatial variation of Peak Ground AccelerationIntra-event spatial variations have been investigated by using the records of seismometer arrays. The findings of this research were summarized in the proceedings of the JSCE.(2) Investigation of Spatial Characteristics of Ground MotionsSeismometer array installed at Saitama University has been expanded. The records of this system and other published records have been analyzed to examine the spatial claracteristics of ground motions such as the speed of horizontal wave propagation and coherence value.(3) Provision of Space-time Ground Motions for Earthquake Resistant DesignThe methods to predict space-time ground motions have been examined and improved for a more accurate representation of the actual wave propagation. A new method has also been developed based on the interpolation of observed records. The numerical stability of this method has been closely investigated for the engineers who are not specialized in waveform analyses.