Are we exceeding the limits of the Great Circle Approximation in global surface wave tomography?
Are we exceeding the limits of the Great Circle Approximation in global surface wave tomography?
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DOI：
10.1029/2000gl012691
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发表时间：
2001-06
影响因子：
5.2
通讯作者：
J. Spetzler;J. Trampert;R. Snieder
中科院分区：
文献类型：
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作者：
J. Spetzler;J. Trampert;R. Snieder
全球表面波层析成像中的射线理论大圆近似仅限于地球模型，在40秒时表面波的最大度为l≤30，在150秒时表面波的最大度为l≤20。这个结果对相速度图和群速度图都成立。目前全球表面波层析成像的最高分辨率接近射线理论的这些极限。为了在未来的表面波层析成像中获得更高程度分辨率的地球模型，有必要考虑表面波的散射。如果仍然采用射线理论，增加地震台网的数据覆盖范围并不能改善层析成像的细节。也必须包括有限频率效应。
The ray theoretical great circle approximation in global surface wave tomography is found to be limited to Earth models with a maximum degree l ≤ 30 for surface waves at 40 s and l ≤ 20 for surface waves at 150 s. This result holds for both phase velocity and group velocity maps. The highest resolution in present‐day global surface wave tomography is close to these limits of ray theory. In order to obtain higher degree resolution models of the Earth in future surface wave tomography, it is necessary to take the scattering of surface waves into account. Increasing the data coverage in seismological networks will not improve the details of tomographic images if ray theory is still applied. It is essential to include the finite‐frequency effects as well.