Large earthquakes rupture faults over hundreds of kilometers within minutes. Finite-fault models image these processes and provide observational constraints for understanding earthquake physics. However, finite-fault inversions are subject to non-uniqueness and uncertainties. The diverse range of published models for the well-recorded 2011 $M_w$ 9.0 Tohoku-Oki earthquake illustrates this challenge, and its rupture process remains under debate. Here, we comprehensively compare 32 published finite-fault models of the Tohoku-Oki earthquake. We aim to identify the most coherent slip features of the Tohoku-Oki earthquake from these slip models and develop a new method for quantitatively analyzing their variations. We find that the models correlate poorly at 1-km subfault size, irrespective of the data type. In contrast, model agreement improves significantly with increasing subfault sizes, consistently showing that the largest slip occurs up-dip of the hypocenter near the trench. We use the set of models to test the sensitivity of available teleseismic, regional seismic, and geodetic observations. For the large Tohoku-Oki earthquake, we find that the analyzed finite-fault models are less sensitive to slip features smaller than 64 km. When we use the models to compute synthetic seafloor deformation, we observe strong variations in the synthetics, suggesting their sensitivity to small-scale slip features. Our newly developed approach offers a quantitative framework to identify common features in distinct finite-fault slip models and to analyze their robustness using regional and global geophysical observations for megathrust earthquakes. Our results indicate that dense offshore instrumentation is critical for resolving the rupture complexities of megathrust earthquakes.

中文翻译：

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有限断层模型的定量比较和验证：2011 年东北冲地震


大地震会在几分钟内使数百公里的断层破裂。有限断层模型对这些过程进行成像，并为理解地震物理学提供观测约束。然而，有限断层反演受制于非唯一性和不确定性。2011 年 $M_w$ 9.0 东北隐岐地震的多种已发布模型说明了这一挑战，其破裂过程仍在争论中。在这里，我们全面比较了 32 个已发表的东北隐岐地震有限断层模型。我们的目标是从这些滑移模型中确定东北隐岐地震最连贯的滑移特征，并开发一种定量分析其变化的新方法。我们发现，无论数据类型如何，模型在 1 km 亚断层大小时相关性很差。相比之下，模型一致性随着子断层大小的增加而显著提高，一致表明最大的滑移发生在海沟附近震源的上倾。我们使用这组模型来测试可用的远程地震、区域地震和大地测量观测的灵敏度。对于大型东北隐岐地震，我们发现所分析的有限断层模型对小于 64 km 的滑移特征不太敏感。当我们使用这些模型计算合成海底变形时，我们观察到合成模型的强烈变化，这表明它们对小尺度滑移特征很敏感。我们新开发的方法提供了一个定量框架，用于识别不同的有限断层滑移模型中的共同特征，并使用区域和全球地球物理观测来分析其对大推力地震的稳健性。我们的结果表明，密集的海上仪器对于解决大推力地震的破裂复杂性至关重要。