＂霍山窗＂地区现代构造应力场研究

Study on recent tectonic stress field in the ＂ Huoshan Seismic Window＂ region

摘要:

应用Snoke于2009年提出的利用P、SV和SH波的初动和振幅比联合计算震源机制解的方法，得到“霍山窗”地区1980年以来62次中小地震的震源机制解。基于大量的震源机制解资料，根据应力张量平均法反演得到“霍山窗”地区的平均构造应力场；结果表明，其与震源机制参数统计结果一致，表现为近EW向的水平挤压和近NS向的水平拉张作用。计算单个震源机制解力轴与平均应力场主应力轴的差异，即震源机制的一致性参数日，进而分析0随时间变化特征及其与华东地区中强震的关系；结果表明，“霍山窗”地区震源机制的一致性参数0对华东地区相应中强震似有一定的指示意义。

Abstract:

The focal mechanisms of 62 moderate-small earthquakes since 1980 in the ＂Huoshan Seismic Window＂ region are calculated with the method developed recently by Snoke which combines the first motion of P, SV and SH waves with their amplitude ratios. Based on these abundant focal mechanisms, mean tectonic stress field in the ＂Huoshan Seismic Window＂ region is inverted with the method of average stress tensor. The result shows that the ＂Huoshan Seismic Window＂ region is horizontally compressed nearly in EW direction and horizontally dilated nearly in NS direction, which is in accordance with statistical results of focal mechanism parameters. We estimate the difference （also referred to as consistency parameter 0） between the force axis direction of focal mechanism solution and the mean stress tensor, then further analyze the variation characteristics of/9 versus time, and the relationship with moderately strong earthquakes in the Eastern China region. The result indicates that 0 in the ＂Huoshan Seismic Window＂ region are in good correspondence with moderately strong earthquakes in the Eastern China region. When 0 is lower than the mean value, corresponding moderately strong earthquakes may occur in the Eastern China region.[著者文摘]