海南岛及邻近地区潜在震源近期强震发生概率的研究

Studying of the probability of occuring strong earthguakes in Hainan Island and the surrounding area in the near future

海南岛及其邻近地区属于中国华南弱地震区，但它是该地震区内地震活动水平相对较高的东南沿海地震带的一部分，该地区经济发达，人口稠密，１９９４年９月１６日发生了台湾海峡７．４级地震，１９９４年１２月３１日和１９９５年１月１０日相继在北部湾发生了６．１级和６．２级地震，如何估计未来本区的地震趋势是一件十分重要和困难的事情．本文以地震地质、地震活动性和地壳形变为前兆特征，采用贝叶斯公式综合估计海南岛及其邻近地区Ｍ＞６的潜在震源区在今后１—３年内的发震概率，取本区发生６级地震的自然概率为本区的平稳无条件概率，结果表明，今后１─３年内，本区在新烈度区划图中给出的Ｍ＞６的５５个潜在震源区中发震概率值大于０．５的地区有９号、４９号和５５号３个潜源区，概率值在０．３—０．５的有６个潜源区，这两类潜源数占潜源总数的１６％，值得密切注意。

Hainan Island and the surrounding is an area where seismicity is weak. However,it is a part of seismic zone in the south-eastern of China.Because of economic develoment and dense population ,it is important and diffecult to evaluate the earthquake tend in the future.The reason is that some earthquakes occured round the area recently (Ms= 7.4,16sept.16,1994 in the Taiwan strait.Ms= 6.1, on Dec.31,1994 and Ms= 6.2,on Jan.10,1995 in Beibu Bay).In the paper, we evaluated theprobility of occuring strong earthquakes (M>6) in Hainan Island and the surrounding area in three years.We use Bayes method to analyse the character of seismo-geology,seismicity and crustal deformation.We suppose that the natural probability of occuring strong earthquakes in the area is steady non-condition probsbility.The result Shows that the probability exceeds 0.5 in 3 potential source areas with No.9,45,55, and others 6 areas have probability with 0.3 0.5.There areas occupy about 16 percent of total and should be pay more attention in the future.