Nontrivial decay of aftershock density with distance in Southern California
Nontrivial decay of aftershock density with distance in Southern California
复制标题
南加州余震密度随距离的非平凡衰减
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
J. Davidsen
中科院分区：
文献类型：
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作者：
Javad Moradpour;S. Hainzl;J. Davidsen
余震密度随距离的衰减在讨论地震触发的主导潜在原因中起着重要的作用。在这里，我们提供的证据表明，它的形式比通常假设的更复杂，特别是在幂律衰减的过渡发生在地壳厚度相当的长度尺度。这得到了最近对南加州（SC）高分辨率目录和流行型余震序列（ETAS）模型生成的替代目录的分析的支持，该模型考虑了不均匀的背景活动，短期余震不完整性，各向异性触发和观测震级阈值的变化。我们的研究结果特别表明，余震密度随距离的渐近衰减的特点是由一个指数大于2，这是远远大于观察到的指数约1.35观察到的距离较短，从主震破裂长度到长度尺度可比的地壳厚度。这对基于ETAS模型的时变地震危险性评估也有重要影响。
The decay of the aftershock density with distance plays an important role in the discussion of the dominant underlying cause of earthquake triggering. Here, we provide evidence that its form is more complicated than typically assumed and that in particular a transition in the power law decay occurs at length scales comparable to the thickness of the crust. This is supported by an analysis of a very recent high‐resolution catalog for Southern California (SC) and surrogate catalogs generated by the Epidemic‐Type Aftershock Sequence (ETAS) model, which take into account inhomogeneous background activity, short‐term aftershock incompleteness, anisotropic triggering, and variations in the observational magnitude threshold. Our findings indicate specifically that the asymptotic decay in the aftershock density with distance is characterized by an exponent larger than 2, which is much bigger than the observed exponent of approximately 1.35 observed for shorter distances ranging from the main shock rupture length up to a length scale comparable to the thickness of the crust. This has also important consequences for time‐dependent seismic hazard assessment based on the ETAS model.
影响因子：
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作者：
S. Hainzl;G. Brietzke;G. Zöller
通讯作者：
S. Hainzl;G. Brietzke;G. Zöller