中国东部烈度衰减关系模型研究

Relational Intensity Attenuation Model of Eastern China

摘要:

本文收集了1990—2021年我国东部地区180次地震等震线数据,采用长、短轴椭圆模型,应用Levenberg-Marquardt法和最小二乘法重新拟合了东部地区的分区地震烈度衰减关系。结果表明,两种回归模型结果保持较好的一致性,在2个分区统计单元内(东北、华北地区与华中、华南地区)地震烈度衰减关系有明显不同,故而应进行不同的分区对待。同时,在我国东部地区,通过与其他学者的地震烈度衰减关系研究成果进行对比,显示本文两种方法的结果可较好地反映烈度衰减的区域特征。选取吉林宁江M5.7、湖北巴东M5.1地震和河北唐山M7.8地震的长、短轴及面积进行计算,通过对比结果可以看出,本文烈度衰减关系计算的结果较同一区域或大区域的计算结果更精准,说明本文结果能反映出东部地区地震震级小而破坏大的特征,适合用于该地区的工程地震研究和应用。本文给出的我国东部地区分区地震烈度衰减关系适用震级范围为面波震级3.0～8.0,距离为0～660km。

Abstract:

In this paper we collect the isoseismal data of 180 earthquakes from 1990 to 2021 in eastern China,adopt the long- and short-axis ellipse model,and apply the Levenberg-Marquardt method and the least squares method to re-fit the regional seismic intensity attenuation relationship in the study region. The results show that the two regression models maintain a good consistency,and the seismic intensity attenuation relationships in the two regional statistical units(Northeast China and North China and Central China and South China) are significantly different,so different partitions should be treated. Moreover,the comparison with the previous results of earthquake intensity attenuation relationship shows that the results of the two methods in this paper better reflect the regional characteristics of intensity attenuation. Taking long,short axis and area calculations of the Ningjiang M5.7 earthquake in Jilin,the Badong M5.1 earthquake in Hubei and the M7.8 earthquake in Hebei Tangshan,we found that the calculation results of the intensity attenuation relationship in this paper are slightly more accurate than that of previous studies. So that the results of this paper can reflect the characteristics of small earthquakes and large damages in the eastern region,and are suitable for engineering earthquake research and applications in this region. The applicable magnitude range of the regional earthquake intensity attenuation relationship in eastern China given in this paper is M3.0～8.0,with the distance of 0～660km.