【摘要】 对湖南及其邻区7°×7°范围内的历史有感地震进行了分析,按照G-R关系推测,研究区自1509年起M≥321地震目录基本完整。研究区现代地震活动水平较弱,而破坏性地震不仅发生的周期较长,且频次较低,在地震活动性研究中很难将现代小震与历史破坏性地震合理地结合起来。考虑了较为完整的有感地震目录后,地震活动性参数统计样本量显著增加,b值拟和的相关系数提高了,拟和方差降低了,拟和结果也更加合理,年发生率ν4的计算也变得更为合理。同时发现,较强历史有感地震的空间分布与深部构造有密切关系。该研究成果对研究区地震安全性评价和地震区划具有参考价值。更多还原

【Abstract】 In this paper,historical felt earthquakes in Hunan Province and its 7°×7° neighborhood are analyzed.We form conjectures upon G-R relationship that the catalogue constituted by earthquakes of a magnitude more than M31/2 is complete grossly from 1509 in research region where modern seismicity is weaker,the intervals between any two stronger earthquakes are relatively longer,and earthquake frequency is lower.It is difficult to connect historical stronger earthquake with modern earthquakes in seismicity research.With historical felt earthquakes taken in account in our work,statistical samples with seismicity parameters increase significantly.Correlation coefficient of b-value fitting is raised,and variance is decreased.These make b-value fitting more reasonable,and make annual occurrence rate calculation more reasonable.Epicenter distribution of historical felt earthquakes is related to deep fault.These results give a significant reference to earthquake safety assessment and seismic zoning.更多还原