An earthquake early warning (EEW) system rapidly analyzes seismic data to report the occurrence of an earthquake before strong shaking is felt at a site. In Japan, the integrated particle filter (IPF) method, a new source‐estimation algorithm, was recently incorporated into the EEW system to improve the source‐estimation accuracy during active seismicity. The problem of the current IPF method is that it uses the trigger information computed at each station in a specific format as the input and is therefore applicable to only limited seismic networks. This study proposes the extended IPF (IPFx) method to deal with continuous waveforms and merge all Japanese real‐time seismic networks into a single framework. The new source determination algorithm processes seismic waveforms in two stages. The first stage (single‐station processing) extracts trigger and amplitude information from continuous waveforms. The second stage (network processing) accumulates information from multiple stations and estimates the location and magnitude of ongoing earthquakes based on Bayesian inference. In 10 months of continuous online experiments, the IPFx method showed good performance in detecting earthquakes with maximum seismic intensity ≥3 in the Japan Meteorological Agency (JMA) catalog. By merging multiple seismic networks into a single EEW system, the warning time of the current EEW system can be improved further. The IPFx method provides accurate shaking estimation even at the beginning of event detection and achieves seismic intensity error <0.25 s after detecting an event. This method correctly avoided two major false alarms on 5 January 2018 and 30 July 2020. The IPFx method offers the potential of expanding the JMA IPF method to global seismic networks.

中文翻译：

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作为高性能地震预警系统的扩展集成粒子滤波器方法 (IPFx)

地震预警 (EEW) 系统可快速分析地震数据，以便在现场感受到强烈震动之前报告地震的发生。在日本，集成粒子滤波器 (IPF) 方法是一种新的震源估计算法，最近被纳入 EEW 系统，以提高活跃地震活动期间的震源估计精度。当前IPF方法的问题在于，它使用在每个站点以特定格式计算的触发信息作为输入，因此仅适用于有限的地震网络。本研究提出了扩展 IPF (IPFx) 方法来处理连续波形并将所有日本实时地震网络合并到一个框架中。新的震源确定算法分两个阶段处理地震波形。第一阶段（单站处理）从连续波形中提取触发和幅度信息。第二阶段（网络处理）积累来自多个站点的信息，并基于贝叶斯推理估计正在进行的地震的位置和震级。在连续10个月的在线实验中，IPFx方法在检测日本气象厅（JMA）目录中最大地震烈度≥3级的地震中表现出良好的性能。通过将多个地震台网合并为一个EEW系统，可以进一步提高当前EEW系统的预警时间。IPFx 方法即使在事件检测开始时也能提供准确的振动估计，并在检测到事件后实现 <0.25 秒的地震强度误差。