Development of a Geodetic Component for the U.S. West Coast Earthquake Early Warning System
Development of a Geodetic Component for the U.S. West Coast Earthquake Early Warning System
复制标题
为美国西海岸地震早期预警系统开发大地测量组件
DOI：
10.1785/0220180162
复制
发表时间：
2018
影响因子：
3.3
通讯作者：
D. Schmidt
中科院分区：
文献类型：
--
作者：
J. Murray;B. Crowell;R. Grapenthin;K. Hodgkinson;J. Langbein;T. Melbourne;D. Melgar;S. Minson;D. Schmidt
美国西海岸正在开发地震预警 (EEW) 系统 ShakeAlert。该系统目前使用地震仪器记录的前几秒波形来快速表征地震震级、位置和起源时间； ShakeAlert 最近添加了地震线源算法。对于大地震，仅根据最早的地震数据估计的震级通常会饱和。实时全球导航卫星系统 (GNSS) 数据可以直接测量大位移，从而能够在破裂终止之前准确估计 M w 7 (cid:1) 事件的震级。 GNSS 测量的位移还跟踪不断变化的滑动，并单独或与地震数据结合，约束有限断层模型。特别是对于大规模、长时间的破裂事件，基于 GNSS 的震级和破裂程度估计可以改进对预测震动的更新，从而提高警报准确性。 ShakeAlert 合作伙伴机构的 GNSS 数据处理中心向 EEW 系统提供实时数据流，并且通过 ShakeAlert 合作开发了三种大地测量 EEW 算法。这些算法将在 ShakeAlert 的计算架构中使用一套输入数据进行初步测试，其中包括合成地震的模拟实时位移和全球最近地震的 GNSS 记录。将使用与 ShakeAlert 整体采用的指标和标准一致的指标和标准来评估性能。该初步评估将指导方法细化，并将最成功的特征合成为 ShakeAlert 生产系统的候选大地测量算法。与此同时，大地测量网络的改进以及简化数据处理和交换方法将确保发生地震时可靠的大地测量数据可用性。 ( ≥ 1 Hz ) 处理后的全球定位系统数据和地震数据已收集用于测试大地地震早期预警算法，并总结了美国西海岸 EEW 系统 ShakeAlert 采用的地面运动指标，用于在生产系统中采用之前评估新的或更新的组件，以及 ShakeAlert 的实时全球导航卫星系统数据流的示意图。
An earthquake early warning (EEW) system, ShakeAlert, is under development for the West Coast of the United States. This system currently uses the first few seconds of waveforms recorded by seismic instrumentation to rapidly characterize earthquake magnitude, location, and origin time; ShakeAlert recently added a seismic line source algorithm. For large to great earthquakes, magnitudes estimated from the earliest seismic data alone generally saturate. Real-time Global Navigation Satellite System (GNSS) data can directly measure large displacements, enabling accurate magnitude estimates for M w 7 (cid:1) events, possibly before rupture termination. GNSS-measured displacements also track evolving slip and, alone or in combi-nation with seismic data, constrain finite-fault models. Particularly for large-magnitude, long-rupture events, GNSS-based magnitude and rupture extent estimates can improve updates to predicted shaking and thus alert accuracy. GNSS data processing centers at ShakeAlert partner institutions provide real-time streams to the EEWsystem, and three geodetic EEW algorithms have been developed through the ShakeAlert collaboration. These algorithms will undergo initial testing within ShakeAlert ’ s computational architecture using a suite of input data that includes simulated real-time displacements from synthetic earthquakes and GNSS recordings from recent earthquakes worldwide. Performance will be evaluated using metrics and standards consistent with those adopted for ShakeAlert overall. This initial assessment will guide method refinement and synthesis of the most successful features into a candidate geodetic algorithm for the ShakeAlert production system. In parallel, improvements to geodetic networks and streamlining approaches to data processing and exchange will ensure robust geodetic data availability in the event of an earthquake. ( ≥ 1 Hz ) processed Global Positioning System data and seismic data have been gathered for use in testing geodetic earthquake early warning algorithms and a summary of ground-motion metrics adopted by ShakeAlert, the U.S. West Coast EEW system, for evaluating new or updated components before adoption in the production system, and a schematic diagram of the real-time Global Navigation Satellite Systems data flow for ShakeAlert.