风暴及台风天气引起的微震现象分析

Analysis of microseisms caused by storm and typhoon

  • 摘要: 本文主要利用时频分析法,基于2016年以来山东省泰安台重力仪及宽频带地震仪观测到的资料,对风暴天气和台风天气引起的微震现象进行研究. 结果表明:这两种天气过程产生的微震信号的频率基本分布在2—20 s之间,能量集中在5—7 s,15 s附近存在一个能量平稳加强的频段;风暴天气产生的微震信号具有由高频向低频演化的动态特征;两种天气条件下产生的微震信号均具有连续、高频及持续时间长的性质,反映了微震信号激发源的移动特征。 结合泰安台微震与风暴和台风天气的一一对应情况,认为微震是一种与近海风暴或远海台风活动有关的微震动过程,而不是与地震有关的前兆异常。

     

    Abstract: We investigate the phenomenon of microseisms caused by storm and typhoon based on the data collected from gravimeter and broadband seismograph of Tai’an station in Shandong Province since 2016 by using the method of time-frequency analysis. The results show that the frequency of microseism signals produced by these two weather processes almost distribute in the range of 2−20 s, and their energy mainly concentrate on 5−7 s, and there is an energy steadily enhanced frequency band near 15 s. Microseism signals generated during storm have a dynamic characteristic of a decreasing frequency.In fact, the microseism signals generated under both weather conditions show a continuous, high frequency and long duration nature, which reflects the moving characteristic of the excitation source of microseisms signals. Considering the correspondence between the microseisms of Tai’an station and the storm and typhoon, it reveals that the microseism is a kind of micro vibration process, which is related to the offshore storm or typhoon in open sea, rather than a precursory anomaly associated with earthquakes.

     

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