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

本研究的目标是：(1)发展地震仪阵列记录的分析方法及其工程应用；(2)地震动空间特征研究；(3)为抗震设计提供时空地震动。（一）地震仪阵列记录分析方法的发展在时域和频域都发展了新的方法来研究波的传播现象。从精度和数值稳定性的角度对这些方法进行了检验。在此基础上，利用实测资料对这些方法进行了验证，并对软土中的非线性波传播进行了讨论。这些结果发表在第11届欧洲地震工程和土壤动力学与地震工程会议论文集上。b)峰值地加速度的空间变化利用地震仪阵列记录研究了事件内空间变化。这项研究的结果在JSCE的会议记录中进行了总结。(2)地震动的空间特征的研究安装在埼玉大学的地震仪阵列已经扩大。对该系统的记录和其他已发表的记录进行了分析，以检验地面运动的空间特征，如水平波传播速度和相干值。(3)为抗震设计提供时空地震动研究和改进了预测时空地震动的方法，以便更准确地表示实际波的传播。此外，还提出了一种基于观测记录插值的新方法。对于不专门从事波形分析的工程师，已经仔细研究了这种方法的数值稳定性。

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.