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摘要
The current independent operating mechanism of regional seismic networks in China makes it possible that there are multiple versions of earthquake catalogs and seismic phase observations at the border areas of adjacent networks, which affects the analysis of seismicity. To solve this problem, we propose a joint probabilistic approach to find out the same events among seismic networks, merging their phase data and relocating the events, and re-yielding the unified catalog in the border region of adjacent networks. The procedures of this approach are presented below. First, we calculate the temporal, spatial and magnitude differences by pairwise comparison of the events among various networks which have the minimum occurrence time difference to obtain the difference distribution of the three source parameters. Second, we find the outlier and ticking out the isolate events. Third, the joint probability is evaluated from the distributions after these steps. Finally, we merge catalogs and phase reports based on the joint probabilistic analysis, relocate and analyze errors. The completeness of the re-yielded catalog can be checked by G-R relationship. We apply this method to the Ludian earthquake sequence. The results show that the phase-merged hypocenter precision is improved significantly compared with that before they are merged, particularly compared with the Sichuan catalog. The merged catalog is similar to the relatively complete Yunnan's catalog, and more precise than that from simple combination of two catalogs. Meanwhile, in the process of catalog merging, M-s rather than M-L magnitude type should be chosen for M-L >= 4. The arrival time information reported by the repeatedly used stations in the merged events can be employed to detect whether there is system bias between different networks. The method presented in this paper makes it possible to form a unified and reliable seismic catalog in the transition region of adjacent networks.
- 出版日期2018-7
- 单位中国地震局
