Scattered waves from low‐frequency earthquakes and plate boundary structure in northern Cascadia
Scattered waves from low‐frequency earthquakes and plate boundary structure in northern Cascadia
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卡斯卡迪亚北部低频地震的散射波和板块边界结构
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
M. Bostock
中科院分区：
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作者：
R. Nowack;M. Bostock
我们使用低频地震（LFE）的3-D波形模拟来研究它们与沿着卡斯卡迪亚北方线性断面的板块边界结构的关系。考虑到地壳速度的不均匀性，一个平滑的俯冲带结构的3-D模型组装，结合区域层析成像和板块边界模型的约束。LFE波形中的散射相是基于合成预测来识别的，该合成预测结合了与高Vp/Vs低速区（LVZ）顶部的倾斜板边界平行对齐的推力机制。近垂直路径的散射主要由来自LVZ的S至P/S至S反射/转换决定。模拟表明，LFEs位于或非常接近板块边界，LVZ结构横向不均匀，但大致符合从地球物理学分析的结果。
We use 3‐D waveform modeling of LFEs (low‐frequency earthquakes) to investigate their relation to plate boundary structure along a linear transect in northern Cascadia. To account for crustal velocity heterogeneity, a smoothed 3‐D model of subduction zone structure is assembled that incorporates constraints from regional tomographic and plate boundary models. Scattered phases within LFE waveforms are identified based on synthetic predictions that incorporate thrust mechanisms aligned parallel to a dipping plate boundary atop a high‐Vp/Vs low‐velocity zone (LVZ). Scattering for near‐vertical paths is dominated by S‐to‐P/S‐to‐S reflections/conversions from the LVZ. The modeling suggests that LFEs lie at or very close to the plate boundary and that the LVZ structure is laterally heterogeneous but broadly consistent with results from teleseismic analysis.