不同尺度地形的SH波频率域响应特征研究

地形是影响实际地震记录的一个重要因素，理论计算已证明地形影响地震波的走时、能量、震相、波形等特征，同时地形也是产生尾波信号的重要原因.复杂且具有多尺度成分的地形对地震波传播的影响不仅与地震信号的频率有关，与其自身尺度成分也表现出强烈的依赖关系. 本文利用局域离散波数法模拟计算了不同尺度地形SH波的频率响应，得到地形尺度与频率之间似共振的响应关系. 这一关系可以更好地解释复杂地形对不同频率地震波传播的影响方式，同时可以指导数值模拟模型的构建，在关注的频率范围内合理取舍构造尺度成分，达到以最小的计算量得到最大的计算效益.

A study on frequency responses of topography with different scales due to incident SH wave

Topography is a main factor affecting ground motion. Theoretical investigations proved that it affects arrival time, energy propagation, and waveform. Moreover, topography is also an important source to produce coda wave. It has been shown that the influence of complex topography on seismic waves not only depends on the spectral nature of seismic source, but also depends on the character of topographical scales. In this article, we simulate frequency responses of topography with multiple spatial scales due to incident SH wave by using the local discrete wave-number method, and obtain a resonance-like relationship and the frequency incident wave. This relationship can help between the scales of topography explanation of the phenomena that frequency frequency of incident wave. It is also useful in constructing the models for synthesizing seismograms. For example, we can ignore those spatial components of a structural model whose contribution to the total seismic response is too small to be accounted to achieve maximum computation efficiency.