Comparing Sensitivities of Geodetic Processing Methods for Rapid Earthquake Magnitude Estimation
Comparing Sensitivities of Geodetic Processing Methods for Rapid Earthquake Magnitude Estimation
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DOI：
10.1785/0220210265
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发表时间：
2022-05-01
影响因子：
3.3
通讯作者：
Mattioli, Glen S.
中科院分区：
文献类型：
--
作者：
Dittmann, Tim;Hodgkinson, Kathleen;Mattioli, Glen S.
根据实时天基大地测量观测数据流快速估计地震震级，提供了一个机会，通过在任何重大和破坏性震动之前发出低延迟警报，减轻大规模和潜在破坏性地震的影响。在过去20年中，大地测量对地震定性和快速震级估计的贡献有所发展，从后处理地震波形到最近提高区域大地测量网络的能力，使全球导航卫星系统能够利用精确单点定位位移估计进行实时地震学研究。此外，在给定震源距离处，地震震级与峰值地面位移（PGD）相关的经验标度律已被证明在快速地震震级估计中是有效的，重点是在大于M-w 6.5的地震中的性能，其中近场地震仪通常饱和。虽然主要的大地测量的贡献，到目前为止，在地震预警的重点是使用三维位置估计和位移，同时努力在时间差分载波相位（TDCP）派生的速度估计也表明，这种方法具有实用性，包括类似的经验得出的比例关系。这项研究建立在以前的努力，在量化的三个组成部分的地面位移和地面速度估计的环境噪声。我们将这些噪声阈值与基于已公布的标度律的预期信号相关联。最后，我们比较了PPP衍生的PGD的性能TDCP衍生的峰值地面速度（PGV），给出了几个丰富的事件数据集。我们的研究结果表明，TDCP-PGV比PPP-PGD更有可能检测到中等震级（类似于M-W 5.0-6.0）地震，尽管震级估计的不确定性更大，震中距离更小。我们的结论是，计算轻量级TDCP派生PGV震级估计是互补的PPP派生PGD震级估计，这可能会产生在网络边缘在高速率和地面运动的敏感性比目前的PPP估计。
Rapid earthquake magnitude estimation from real-time space-based geodetic observation streams provides an opportunity to mitigate the impact of large and potentially damaging earthquakes by issuing low-latency warnings prior to any significant and destructive shaking. Geodetic contributions to earthquake characterization and rapid magnitude estimation have evolved in the last 20 yr, from post-processed seismic waveforms to, more recently, improved capacity of regional geodetic networks enabled real-time Global Navigation Satellite System seismology using precise point positioning (PPP) displacement estimates. In addition, empirical scaling laws relating earthquake magnitude to peak ground displacement (PGD) at a given hypocentral distance have proven effective in rapid earthquake magnitude estimation, with an emphasis on performance in earthquakes larger than similar to M-w 6.5 in which near-field seismometers generally saturate. Although the primary geodetic contributions to date in earthquake early warning have focused on the use of 3D position estimates and displacements, concurrent efforts in time-differenced carrier phase (TDCP)-derived velocity estimates also have demonstrated that this methodology has utility, including similarly derived empirical scaling relationships. This study builds upon previous efforts in quantifying the ambient noise of three-component ground-displacement and ground-velocity estimates. We relate these noise thresholds to expected signals based on published scaling laws. Finally, we compare the performance of PPP-derived PGD to TDCP-derived peak ground velocity (PGV), given several rich event datasets. Our results indicate that TDCP-PGV is more likely than PPP-PGD to detect intermediate magnitude (similar to M-w 5.0-6.0) earthquakes, albeit with greater magnitude estimate uncertainty and across smaller epicentral distances. We conclude that the computationally lightweight TDCP-derived PGV magnitude estimation is complementary to PPP-derived PGD magnitude estimates, which could be produced at the network edge at high rates and with increased sensitivity to ground motion than current PPP estimates.