用叠加谱比法研究四川地区Lg尾波Q值的区域性变化

 运用单台叠加谱比法,分析了成都台网4个台站的29个地震记录的垂直分量,反演得出与各射线路径相对应的Lg尾波的Q₀值.结果表明:Q₀值的分布特征与构造活动性密切相关.在构造活动剧烈的龙门山断裂、鲜水河断裂和安宁河断裂,尤其是在这三大断裂的交汇处,Q₀值呈现出相当低的值,约在150～210的范围内.在四川盆地的大部分地区,随着构造活动的减弱,Q₀值有所抬升,约为240～270.在四川盆地的东部,Q₀值可达300.在离开断裂区的四川北部,Q₀值在250～300的范围内变化.

Regional variation of Lg coda Q in Sichuan region using stack spectral ratio method

The vertical components of 29 earthquake records received by 4 stations of Chengdu Network were analyzed with the single station stack spectral ratio method,and inverted the Lg coda Q₀ for each path.Results indicate that the distribution characteristics of Q₀ correlates with geotectonics closely.In tectonical active regions including Longmenshan fault,Xianshuihe fault,and Anninghe fault,especially in the junction of the three faults,Q₀ exhibits very low values varying from 150-210.In most areas of Sichuan Basin,Q₀ somewhat increases,with the decreasing of tectonics whose values being from 240-270.In the east part of Sichuan Basin,Q₀ can arrive at 300.In the north part of Sichuan away from fault regions,Q₀ varies from 250 to 300.