We present a database and analyze ground motions recorded during three events that occurred as part of the July 2019 Ridgecrest earthquake sequence: a moment magnitude (M) 6.5 foreshock on a left‐lateral cross fault in the Salt Wells Valley fault zone, an M 5.5 foreshock in the Paxton Ranch fault zone, and the M 7.1 mainshock, also occurring in the Paxton Ranch fault zone. We collected and uniformly processed 1483 three‐component recordings from an array of 824 sensors spanning 10 seismographic networks. We developed site metadata using available data and multiple models for the time‐averaged shear‐wave velocity in the upper 30 m (⁠VS30⁠) and for basin depth terms. We processed ground motions using Next Generation Attenuation (NGA) procedures and computed intensity measures including spectral acceleration at a number of oscillator periods and inelastic response spectra. We compared elastic and inelastic response spectra to seismic design spectra in building codes to evaluate the damage potential of the ground motions at spatially distributed sites. Residuals of the observed spectral accelerations relative to the NGA‐West2 ground‐motion models (GMMs) show good average agreement between observations and model predictions (event terms between about −0.3 and 0.5 for peak ground acceleration to 5 s). The average attenuation with distance is also well captured by the empirical NGA‐West2 GMMs, although azimuthal variations in attenuation were observed that are not captured by the GMMs. An analysis considering directivity and fault‐slip heterogeneity for the M 7.1 event demonstrates that the dispersion in the near‐source ground‐motion residuals can be reduced.

中文翻译：

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2019年Ridgecrest地震序列中记录的地震动的工程特征

我们提供了一个数据库并分析了在2019年7月Ridgecrest地震序列中发生的三个事件中记录的地面运动：盐井谷断层带左交叉断层的矩震级（M）6.5前震，M 5.5 Paxton Ranch断裂带发生前震，M 7.1主震也发生在Paxton Ranch断裂带。我们从824个跨越10个地震台网的传感器中收集并统一处理了1483个三分量记录。我们使用可用数据和多个模型开发了站点元数据，以用于30 m以内的时间平均剪切波速度（⁠VS30⁠）和盆地深度项。我们使用下一代衰减（NGA）程序处理了地面运动，并计算了强度测量值，包括多个振荡器周期的频谱加速度和非弹性响应频谱。我们在建筑规范中将弹性和非弹性响应谱与抗震设计谱进行了比较，以评估空间分布点处地震动的潜在破坏力。相对于NGA-West2地面运动模型（GMM）观察到的频谱加速度的残差显示，观测值与模型预测之间具有良好的平均一致性（对于峰值加速度5 s，事件项介于-0.3和0.5之间）。NGA-West2 GMM的经验值也可以很好地捕获带距离的平均衰减，尽管观察到衰减的方位角变化没有被GMM捕获。