After destructive earthquakes, it is a challenge to estimate magnitude rapidly and accurately for dissemination to emergency responders and the public. Here, we propose criteria to calculate peak ground displacement (PGD) from strong‐motion records, which can be used to calculate unsaturated event magnitude. Using collocated strong‐motion and Global Navigation Satellite Systems observations of five major earthquakes in Japan, we demonstrate the effectiveness and accuracy of our strategy. Our results show that, with the right filtering criteria, PGD estimated from strong‐motion acceleration waveforms is consistent with geodetic estimates. The methodology, however, does not allow for calculation of reliable estimates of coseismic deformation or other ground displacement metrics. We demonstrate a simulated real‐time magnitude estimation that suggests it is feasible to generate an unsaturated magnitude estimate in real time from near‐field strong‐motion records. These findings have important implications for early warning and emergency response in seismically active areas, especially where real‐time strong‐motion data are more widely available than geodetic measurements.

中文翻译：

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强运动波形不饱和的幅度计算

在破坏性地震发生后，如何快速准确地估计震级以向应急人员和公众传播是一个挑战。在此，我们提出了根据强运动记录计算峰值地面位移（PGD）的标准，该标准可用于计算非饱和事件的大小。通过使用强动和全球导航卫星系统对日本五场大地震的并置观测，我们证明了该策略的有效性和准确性。我们的结果表明，使用正确的过滤标准，从强运动加速度波形估计的PGD与大地测量的估计是一致的。然而，该方法不允许计算同震变形或其他地面位移度量的可靠估计。我们演示了模拟的实时震级估计，这表明从近场强运动记录实时生成非饱和震级估计是可行的。这些发现对地震活跃地区的预警和紧急响应具有重要意义，尤其是在实时强运动数据比大地测量更为广泛的地方。