Prediction of maximum P- and S-wave amplitude distributions incorporating frequency- and distance-dependent characteristics of the observed apparent radiation patterns
Prediction of maximum P- and S-wave amplitude distributions incorporating frequency- and distance-dependent characteristics of the observed apparent radiation patterns
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DOI：
10.1186/s40623-016-0544-8
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发表时间：
2016-10-21
影响因子：
3
通讯作者：
Yoshimoto, Kazuo
中科院分区：
文献类型：
--
作者：
Takemura, Shunsuke;Kobayashi, Manabu;Yoshimoto, Kazuo
视辐射图的频率依赖模型已被广泛地应用于高频地震波的工程和科学应用中，但距离依赖特性尚未得到充分考虑。本文研究了局部地壳地震中P波和S波视辐射图象的频率和距离依赖性的统一特征。观察到的失真的明显的P-和S-波辐射图案可以简单地通过使用的归一化震源距离，这是一个产品的波数和震源距离的函数建模。这种现象表明，地震波在非均匀地壳中的散射和绕射是造成视辐射图畸变的主要原因。在观测到的归一化震源距离依赖性的基础上，我们提出了一种预测最大P波和S波振幅空间分布的方法。我们的方法结合归一化震源距离依赖的表观辐射图案再现了所观察到的最大P-和S-波振幅在很宽的频率和距离范围内的空间分布成功。
Frequency-dependent model of the apparent radiation pattern has been extensively incorporated into engineering and scientific applications for high-frequency seismic waves, but distance-dependent properties have not yet been fully taken into account. We investigated the unified characteristics of frequency and distance dependences in both apparent P- and S-wave radiation patterns during local crustal earthquakes. Observed distortions of the apparent P- and S-wave radiation patterns could be simply modeled by using a function of the normalized hypocentral distance, which is a product of the wave number and hypocentral distance. This behavior suggests that major cause of distortion of the apparent radiation pattern is seismic wave scattering and diffraction within the heterogeneous crust. On the basis of observed normalized hypocentral distance dependency, we proposed a method for prediction of spatial distributions of maximum P- and S-wave amplitudes. Our method incorporating normalized hypocentral distance dependence of the apparent radiation pattern reproduced the observed spatial distributions of maximum P- and S-wave amplitudes over a wide frequency and distance ranges successfully.