Global oceanic microseism sources as seen by seismic arrays and predicted by wave action models
Global oceanic microseism sources as seen by seismic arrays and predicted by wave action models
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DOI：
10.1029/2011gc003875
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发表时间：
2010-12
期刊：
影响因子：
3.7
通讯作者：
G. Hillers;Nicholas E. Graham;Michel Campillo;Sharon Kedar;M. Landès;N. M. Shapiro
中科院分区：
文献类型：
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作者：
G. Hillers;Nicholas E. Graham;Michel Campillo;Sharon Kedar;M. Landès;N. M. Shapiro
我们分析了 2000 年 7 月至 2001 年 6 月期间的全球微震激发模式。将地震观测结果与建模结果进行比较，以隔离相关震源过程的稳健活动特征。首先，我们使用 Landès 等人估计的微震震源位置的观测结果。 (2010) 基于环境噪声相关性的阵列处理。其次，我们通过将从波浪作用模型得出的海况估计与微震激发理论相结合来构建合成活动模式。两种估计的总体时空演变都具有季节性特征，与冬季的强烈活动相关。陆地分布导致北半球（NH）的季节变化超过南半球（SH）的变化。我们对这两个估计值的系统比较揭示了沿海岸线和公海的显着微震激发。由于建模方法中没有考虑海岸反射，近海岸观测与预测之间的一致不匹配表明，到达网络的相关微震能量是在这些区域产生的。同时，远离海岸线的系统巧合验证了公海生成假说。这些结论对于 NH 上的地震台网位置而言具有普遍性和稳健性。我们的合成材料的空间均匀分辨率为评估全球微震天气提供了宝贵的资源。与之前确定的北大西洋热点区域类似，建模的分布假设了南太平洋上局部活动强烈的区域，但分析的数据集仅部分证实了这一点。
We analyze global microseism excitation patterns between July 2000 and June 2001. Seismological observations are compared with modeling results to isolate robust activity features of relevant source processes. First, we use observations of microseism source locations estimated by Landès et al. (2010) based on array processing of ambient noise correlations. Second, we construct synthetic activity patterns by coupling sea state estimates derived from wave action models to the excitation theory for microseisms. The overall spatiotemporal evolution of both estimates is characterized by a seasonal character that is associated with strong activity during winter months. The distribution of landmass causes seasonal changes on the Northern Hemisphere (NH) to exceed the variability on the Southern Hemisphere (SH). Our systematic comparison of the two estimates reveals significant microseism excitation along coastlines and in the open ocean. Since coastal reflections are not accounted for in the modeling approach, the consistent mismatch between near‐coastal observations and predictions suggests that relevant microseism energy arriving at the networks is generated in these areas. Simultaneously, systematic coincidence away from coastlines verifies the open ocean generation hypothesis. These conclusions are universal and robust with respect to the seismic network locations on the NH. The spatially homogeneous resolution of our synthetics provides a valuable resource for the assessment of the global microseism weather. Similar to previously identified hot spot areas in the North Atlantic, the modeled distributions hypothesize regions of strong localized activity on the SH, which are only partially confirmed by the analyzed data sets.