黎明晓,刘杰,薛艳,姜祥华,苑争一,闫伟,于磊. 2024. 鲁东—黄海地块西部中强地震活动特征及周边地震对该地区的影响. 地震学报,46(3):377−393. doi: 10.11939/jass.20220150
引用本文: 黎明晓,刘杰,薛艳,姜祥华,苑争一,闫伟,于磊. 2024. 鲁东—黄海地块西部中强地震活动特征及周边地震对该地区的影响. 地震学报,46(3):377−393. doi: 10.11939/jass.20220150
Li M X,Liu J,Xue Y,Jiang X H,Yuan Z Y,Yan W,Yu L. 2024. Characteristics of moderate-strong seismicity in the western Ludong-Huanghai block and the influence from surrounding earthquakes. Acta Seismologica Sinica46(3):377−393. doi: 10.11939/jass.20220150
Citation: Li M X,Liu J,Xue Y,Jiang X H,Yuan Z Y,Yan W,Yu L. 2024. Characteristics of moderate-strong seismicity in the western Ludong-Huanghai block and the influence from surrounding earthquakes. Acta Seismologica Sinica46(3):377−393. doi: 10.11939/jass.20220150

鲁东—黄海地块西部中强地震活动特征及周边地震对该地区的影响

Characteristics of moderate-strong seismicity in the western Ludong-Huanghai block and the influence from surrounding earthquakes

  • 摘要: 鲁东—黄海地块西部为华北地块东侧的次级地块,其地震活动具有显著的周期特征,地块内部的中强地震活动特征和周边大震对该地区的影响对研究该地区地震活动状态有重要意义。采用小波分析方法定量计算了鲁东—黄海地块西部历史地震的活动周期,并结合中强地震活动的定性分析、时空演化、能量释放及周边大震等资料,探讨了该地区的地震活动特征。结果显示:① 鲁东—黄海地块西部M5.0以上地震活动存在着60.6—78.6 a的长周期,该周期反映了地震活跃—平静的韵律特征,据此M≥5.0地震可划分为活跃时段 Ⅰ (1844—1879年)、活跃时段 Ⅱ(1905—1949年)和活跃时段Ⅲ(1974年至今)。1997年以来,该地区处于活跃时段末期的弱释放阶段;② 在三个活跃时段,地震活动的主体地区不同,活跃时段 Ⅰ , Ⅱ以海域地震活动为主,并且地震活动水平海域强、陆域弱。活跃时段Ⅲ陆域、海域均有M≥6.0地震活动;③ 1815年以来,鲁东—黄海地块西部M≥5.0地震与华北M≥6.0地震活动大致同步,当鲁东—黄海地块西部中强地震恰好处于较强活跃时段时,华北地块M6.0地震显著平静后,M≥6.0地震先从鲁东—黄海地块西部开始活动,然后向华北地块中西部地区活动;④ 当太平洋板块西侧的俯冲带上MW≥5.0中深源地震活跃,并发生MW≥7.0地震时,鲁东—黄海地块西部易于发生MS≥6.0地震,这可能是太平洋板块西侧深部俯冲构造动力作用增强导致的结果。

     

    Abstract: The seismicity in the western Ludong-Huanghai block, a sub block in the eastern side of the North China block, has a significant periodic characteristic. Therefore, it is of great importance to study the seismicity in this area, the characteristics of its internal moderate strong seismicity and the influence from surrounding large earthquakes. In this paper, the wavelet analysis method is used to quantitatively calculate the activity period of historical earthquakes in the block. At the same time, in combination with the data on qualitative analysis of moderate-strong earthquakes, spatio-temporal evolution, energy release and the influence from surrounding large earthquakes, the state and characteristics of seismicity in the block are discussed. The results show that: ① There is a long periodicity of 60.6−78.6 years for M≥5.0 earthquakes in the western Ludong-Huanghai block, which reflects the rhythmic characteristics of seismic active-quiescence. Based on which, M≥5.0 earthquakes can be divided into active periods Ⅰ (1844−1879), Ⅱ (1905−1949), and Ⅲ (1974 to present). Since 1997, the seismicity in the western Ludong-Huanghai block has been in the weak release stage at the end of the active period; ② In the three active periods, the main seismic areas are different. In the first and second active periods, the seismicity in the sea is dominant, and the earthquakes in the sea are stronger than those in the land, while in the third active period, it is very different. In which, M≥6.0 earthquakes presented in both land and sea; ③ Since 1815, M≥5.0 earthquakes in the western Ludong-Huanghai block and those with M≥6.0 earthquakes in the North China block have roughly exhibited synchronous activity characteristics. In other words, when M≥5.0 earthquakes in the western Ludong-Huanghai block happen in a strong active period, it generally firstly broke the significant calm of M≥6.0 earthquakes in the North China block. Then, the seismicity moves towards the central and western areas of the North China block; ④ When intermediate and deep-focus earthquakes with MW≥5.0 in the subduction zone are active and those with MW≥7.0 happen at the same time on the western side of the Pacific plate, it may promote the occurrence of MS≥6.0 earthquakes in the western Ludong-Huanghai block, which may reflect the strengthening of deep subduction tectonic dynamic action.

     

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