Multifrequency inversion of global ambient seismic sources
Multifrequency inversion of global ambient seismic sources
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DOI：
10.1093/gji/ggab050
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发表时间：
2021-03
影响因子：
2.8
通讯作者：
L. Ermert;K. Sager;T. Nissen‐Meyer;A. Fichtner
中科院分区：
文献类型：
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作者：
L. Ermert;K. Sager;T. Nissen‐Meyer;A. Fichtner
我们开发并应用一种方法来约束环境噪声源的空间和频率相关的位置。这是基于使用数值波场模拟的环境噪声互相关反演，其中尊重三维地壳和地幔结构，海洋负荷和有限频率效应。在3到20兆赫的频率范围内，我们的结果限制了全球源分布的地球的嗡嗡声，平均在南半球冬季的9年。在南半球冬季，主要的源主要局限于南半球，最突出的例外是伊豆-小笠原-马里亚纳弧，这是12和20兆赫之间最活跃的源区域。一般来说，强烈的嗡嗡声源似乎与海岸线或水深高点有关。相比之下，深海盆地没有嗡嗡声源。虽然是基于相对较少的STS-1宽带站已连续记录从2004年至2013年，我们的研究结果表明，占3-D波传播的复杂性的频率相关的噪声源反演的实际可行性。因此，它可以改善全波形环境噪声反转和我们对噪声产生的物理学的理解。
We develop and apply a method to constrain the space- and frequency-dependent location of ambient noise sources. This is based on ambient noise cross-correlation inversion using numerical wavefield simulations, which honour 3-D crustal and mantle structure, ocean loading and finite-frequency effects. In the frequency range from 3 to 20 mHz, our results constrain the global source distribution of the Earth’s hum, averaged over the Southern Hemisphere winter season of 9 yr. During Southern Hemisphere winter, the dominant sources are largely confined to the Southern Hemisphere, the most prominent exception being the Izu-Bonin-Mariana arc, which is the most active source region between 12 and 20 mHz. Generally, strong hum sources seem to be associated with either coastlines or bathymetric highs. In contrast, deep ocean basins are devoid of hum sources. While being based on the relatively small number of STS-1 broad-band stations that have been recording continuously from 2004 to 2013, our results demonstrate the practical feasibility of a frequency-dependent noise source inversion that accounts for the complexities of 3-D wave propagation. It may thereby improve full-waveform ambient noise inversions and our understanding of the physics of noise generation.