三峡工程水库重点监视区不同蓄水阶段地震波Q值分析

摘要

利用2001～2015年三峡数字遥测地震台网记录到的数字地震观测资料,结合三峡工程水库蓄水情况,采用Atkinson方法分析该地区的地震波衰减特征,得到不同蓄水阶段、不同库段的非弹性衰减结果.结果显示,Q值与频率变化的线性关系较好,各频点在拟合线附近波动;3个库段在不同蓄水阶段均具有较小的Q0值和中等的η值,表明三峡工程水库重点监视区构造复杂,且介质的均匀程度较低;仙女山-九畹溪断裂附近地区Q值较大,表明该地区构造运动比较稳定;巴东高桥断裂附近地区Q值较小,表明该地区构造运动比较强烈;泄滩地区随着水位的升高,Q0值增大,表明该地区介质均匀程度有所提高.%With seismic waveform data from 2001 to 2015 recorded by the Three Gorges digital earthquake network,the inelastic attenuation coefficients in different water impoundment phases are calculated.The well-fitting results suggest that the linear relationship between the Q value and the frequency is significant.In general,the Q0 value and η value at different impoundment stages are similar,and relatively not so large.This indicates that the tectonic structures in the study area are very complex and the frequency of the mirco small earthquakes is high.In addition,the medium in this region is very heterogeneous.The Q value near the Xiannvshan-Jiuwanxi fault is large,which shows that the region is relatively tectonically stable.While the Q value in Badong region is small,it might denote that tectonic activity is stronger.For the Xietan region,the Q value becomes larger with the water level increasing,showing that the medium becomes more and more homogeneous.