2016年门源MS6.4地震前兆异常演化特征

Evolution characteristics of precursory anomalies before the MS6.4 Menyuan,Qinghai,earthquake in 2016

  • 摘要: 本文对2016年青海门源MS6.4地震之前震中周边前兆台站的观测资料进行了回顾性分析,结果显示有15项定点前兆测项震前呈异常,主要集中在距震中300 km的范围内,其中形变类异常最先出现,之后以流体类异常为主,临震阶段以电磁类异常为主。震前前兆异常的演化在时空上具有阶段性和迁移性,震前异常出现时间随震中距的变化划分为三个阶段:α阶段为远源场前兆异常从震中向外围扩散的过程,异常主要出现在震前390—630天;β阶段为前兆异常大范围分布,主要出现在震前100—200天;γ阶段主要为近源场异常向外扩散。

     

    Abstract: By retrospectively analyzing and sorting out the anomalies before the 2016 Menyuan MS6.4 earthquake, this paper discusses the spatio-temporal evolution characteristics of precursory anomalies before the earthquake. The results show that the anomalies are mainly concentrated in the region within 300 km around the epicenter. Among all kinds of the anomalies, deformation anomalies appeared first, followed by medium- and short-term fluid anomalies, and electromagnetic anomalies in the impending earthquake stage. The evolution of precursory anomalies appears as stage and migration characteristics in space-time. The variation of pre-earthquake anomalies can be divided into α, β, γ three stages. During the α stage, the precursory anomalies spread from the epicenter to the periphery in the far source field mainly 390−630 days before earthquakes. During the β stage, the precursory anomalies are widely distributed in 100−200 days before earthquakes. During the γ stage, the precursory anomalies of the near-field source spread outwards.

     

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