云南地区中强震丛集和连发研究

Mid-strong Earthquake Clustering and Continuously Occurring in the Yunnan Area

利用云南地震目录,分析了1900年以来云南地区所发生的中强地震连发事件,探讨了这些连发地震对未来地震活跃期首发强震的指示意义,并对云南地区第5活跃期的起始时间和地点进行了探讨。结果表明,云南地区5级以上中强地震有典型的丛集分布特性,显示出平静—活跃交替出现的现象,地震活动的优势周期约为19年;中强地震能量释放折合震级随时间的分布特征,对云南强震尤其是活跃期首发强震有较好的指示作用;地震平静期中连发地震释放的能量、地震丛数和地震个数对下一个地震活跃期首发强震的时间指示意义比较明显,连发地震能量释放主体地区及周边地区对发震地点也具有一定指示意义。

The continuous occurrences of the mid-strong earthquakes in the Yunnan area since 1900 have been analyzed by using the Yunnan earthquake catalogues. The results show that the M≥5 mid-strong earthquakes in the Yunnan area have typical characteristics of cluster distribution, indicating an alternate activity between quiet and active with a period of 19 years. The converted magnitude-time distribution from the energy release of mid-strong earthquakes is referential to predict the strong earthquake in Yunnan, especially the first strong earthquake in the following seismic active period. The energy release the number of clusters and the number of the earthquakes continuously occurring in the quiet period have obvious reference to the time of the first strong earthquake in the following active period; and the major energy release areas and nearby also have a certain reference to the location of the earthquake.