Probabilistic seismic source inversion of the 1886 Charleston, South Carolina, earthquake from macroseismic evidence: A major updating
Probabilistic seismic source inversion of the 1886 Charleston, South Carolina, earthquake from macroseismic evidence: A major updating
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根据宏观地震证据对 1886 年南卡罗来纳州查尔斯顿地震进行概率震源反演：重大更新
DOI：
10.1016/j.enggeo.2022.106958
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发表时间：
2023
影响因子：
7.4
通讯作者：
Maurer, Brett W.
中科院分区：
文献类型：
--
作者：
Rasanen, Ryan A.;Maurer, Brett W.
1886年南卡罗来纳州查尔斯顿地震的震源影响了美国东南部的地震危险性计算，从而影响了公共政策和工程实践。然而，由于1886年的破裂早于地震仪器，它的来源是高度不确定的。这项研究提出了概率震源反演的查尔斯顿地震液化证据和历史烈度报告。使用最新的预测模型和一种新的反演方法，我们试图限制1886年破裂的大小，位置和方向。破裂震级的概率分布的条件下的“伍德斯托克故障”-一个共同推断的1886年事件的来源-和一个未知的来源，其中故障的位置和方向的不确定性被认为是。将这些分布与美国国家地震灾害模型项目（NSHMP）采用的Mw6.7-Mw7.5分布进行比较。总的来说，这些结果并没有为假设的伍德斯托克断层提供强有力的支持。这并不是说伍德斯托克断层不存在或不可能导致1886年的破裂，而是说，1886年震源模型的位置不能受到本文研究的数据和模型的约束，因为每个模型都有很大的不确定性。虽然这与先前研究的基本假设不一致，但结果通常支持NSHMP采用的震级分布。确定了这一分布所固有的最大不确定性，并可在今后予以减少。最后，我们注意到，这里使用的反演方法不是特定于任何地区，或某些类型的证据，但可以应用于任何地震带和任何同震响应。当从宏观地震数据反演震源参数时，这种方法允许以更完整和透明的方式考虑不确定性。当然，必须理解这些数据固有的任何限制、偏差或未建模的不确定性，并承认其含义，如本文进一步讨论的。
The source of the 1886 Charleston, South Carolina earthquake influences the computed seismic hazard of the Southeastern U.S. and thus impacts public policy and engineering practice. However, because the 1886 rupture predated seismic instruments, its source is highly uncertain. This study presents probabilistic seismic-source inversions of the Charleston earthquake from liquefaction evidence and historical intensity reports. Using the latest predictive models and a novel inversion approach, we seek to constrain the magnitude, location, and orientation of the 1886 rupture. Probability distributions of rupture magnitude are conditioned on both the “Woodstock Fault” – a commonly inferred source of the 1886 event – and on an unknown source, wherein the uncertainties of fault location and orientation are considered. These distributions are compared to the Mw6.7-Mw7.5 distribution adopted by the U.S. National Seismic Hazard Model Project (NSHMP). Collectively, the results do not provide strong support for the hypothesized Woodstock Fault. This is not to say the Woodstock Fault does not exist or could not have caused the 1886 rupture, but rather, that the position of the 1886 source model cannot be constrained by the data and models studied herein, given the large uncertainties inherent to each. While this is at odds with the underlying assumption of prior studies, the results nonetheless generally uphold the magnitude distribution adopted by the NSHMP. The largest uncertainties inherent to this distribution are identified and could be diminished in the future. Finally, we note that the inversion methodology used here is not specific to any region, or to certain types of evidence, but can be applied to any seismic zone and to any co-seismic response. This methodology allows for uncertainty to be accounted for in a more complete and transparent manner when inverting seismic source parameters from macroseismic data. Of course, any limitations, biases, or unmodeled uncertainties inherent to these data must be understood, and their implications acknowledged, as further discussed herein.