Publication Date:
2023-08-09
Description:
Foreshocks could provide valuable information for seismogenic process. Similar to aftershocks and swarms, foreshocks are usually clustered in time and space, which could result in low magnitude earthquakes being overwhelmed by the coda waves of other earthquakes. In addition, the limited observation condition could result in the loss of small earthquakes in local catalog. The waveform correlation technique has been proved to be an effective method to detect missing small earthquakes and widely used in foreshock and aftershock sequence detection. On January 19, 2020, the M〈sub〉S〈/sub〉6.4 earthquake occurred in Jiashi, Xinjiang. About 45 hours before the earthquake, the M〈sub〉S〈/sub〉5.4 earthquake occurred in the focal area, which formed a typical foreshock sequence. In this study, we collected the continuous waveforms between December 1, 2019 and January 31, 2020 from 6 stations located within 100 km of the mainshock. With 791 relocated earthquakes (including 33 foreshocks) as templates, 4664 earthquakes (including 261 foreshocks) were detected and located by the Match Locate method. The complete magnitude of the catalog was reduced from M〈sub〉L〈/sub〉1.6 to M〈sub〉L〈/sub〉1.0. With the enhanced catalog, we observe that the foreshock sequence has lower b-value than aftershocks and lacks small-magnitude (M〈sub〉L〈/sub〉〈0.3) events, which are generally consistent with other studies. According to the spatial and temporal evolution of the earthquake sequence, seismicity becomes relative quiet within 26 days before the Jiashi M〈sub〉S〈/sub〉5.4 earthquake and 2 days before the mainshock. In addition, the earthquakes during the two days before the mainshock migrated to the mainshock epicenter.
Language:
English
Type:
info:eu-repo/semantics/conferenceObject
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