利用小震震源机制解研究太行山断裂带东南缘地区构造应力场

摘要

The focal mechanism solutions of 68 small and medium earthquakes,whichoccurred in the southeastern margin region of Taihang mountains fault zone (TMFZ),are determined by the amplitude ratio of PG and SG in vertical component records with clear initial motion.The parameters of focal mechanism solutions are analyzed using statistical and cluster analysis.The average stress field azimuth of area is calculated with the method of mechanical axis tensor.The results show that the main focal mechanism solutions arestrike-slip type in the research area,and the proportion is 57％.There are also normal and inverse fault types.The dips of both maximum and minimum stress axis are small,relatively close to level.The analysis indicates that the main characteristics of the tectonic stress field of research area are nearly NEE-SWW compression and nearly NNW-SSE expansion.%利用P波初动和垂直向记录Pg、Sg振幅比方法,计算得到在太行山断裂带东南缘地区68个中小地震的震源机制解.通过统计方法、系统聚类分析方法分析震源机制解参数,并利用力轴张量计算方法求取区域平均应力场.结果表明,研究区68个中小地震震源机制解走滑类占总数的57％,正断类与逆断类也都存在;最大、最小应力轴倾角都较小,接近水平.该区现今构造应力场的主要特征表现为北东东-南西西向的水平挤压与北北西-南南东向的水平拉伸.