S‐to‐Rayleigh Wave Scattering From the Continental Margin Observed at USArray
S‐to‐Rayleigh Wave Scattering From the Continental Margin Observed at USArray
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USArray 观测到的大陆边缘 S 至瑞利波散射
DOI：
10.1029/2017gl076812
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发表时间：
2018
影响因子：
5.2
通讯作者：
P. Shearer
中科院分区：
文献类型：
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作者：
J. Buehler;N. Mancinelli;P. Shearer
我们展示了西太平洋地震产生的S波在美国西部海岸线附近转换为表面波的例子。其中许多事件起源于汤加-萨摩亚地区。我们观察到这些表面波转换在USAray站在相对较长的周期（>10秒）。不同观测站的振幅差异很大，在黄石地区出现了高度放大。二维谱元模拟成功地从入射SV波和具有海岸线表面地形和边缘地壳厚度变化的模型生成了散射瑞利波，尽管简单模型无法解释在某些地区观察到的大瑞利波振幅（大于直接S波振幅），这表明波列被局部结构或三维聚焦效应放大。
We show examples of teleseismic S waves from western Pacific earthquakes converting to surface waves near the western U.S. coastline. Many of these events originate in the Tonga‐Samoa region. We observe these surface wave conversions at USArray stations at relatively long periods (>10 s). The amplitudes vary considerably from station to station and appear highly amplified in the Yellowstone region. Two‐dimensional spectral element simulations successfully generate scattered Rayleigh waves from incident SV waves and models with surface topography at the coastline and crustal thickness variations across the margin, although simple models cannot explain the large Rayleigh wave amplitudes (greater than the direct S wave amplitude) observed in some regions, suggesting that the wave train is amplified by local structure or 3‐D focusing effects.