【摘要】 利用中国地震年报(1984~2004年)测定ML所用的54000余条区域地震最大振幅数据,采用二维层析成像方法反演中国大陆地壳介质品质因子Q0结构.反演结果表明,中国大陆地壳介质品质因子Q0平均为370,Q0横向变化量可达±200.在整个研究区解的分辨率能够达到3°×3°,大部分地区能够达到2°×2°.Q0的变化显示出与地质构造分区相关的特征:低衰减(高Q0值)异常区主要分布在塔里木盆地、四川盆地、鄂尔多斯高原及华南地区,鄂尔多斯高原北部Q0值最高;高衰减异常区(低Q0值)主要分布在青藏高原以东的川滇地区、华北平原、渤海湾,最低Q0值在渤海湾地区,天山、祁连山和汾渭地堑Q0也呈较低异常变化.总体看来,构造上稳定的克拉通地台的介质品质因子Q0较高,而构造上活动的地区往往Q0较低,显现出区域的衰减变化特征与地壳结构和区域构造之间的密切关系.更多还原

【Abstract】 Over 54000 S wave amplitude and period data reported in the Annual Bulletin of Chinese Earthquakes （1984-2004） for M_L determination were used to study the S wave attenuation and the regional variation of crustal attenuation in China. A two-dimensional tomography method is adopted to find regional attenuation variation. We obtained an average Q₀ （Q at 1 Hz） value of 370 for the entire studied region with regional fluctuations ±200. Features larger than 2 degrees in most parts of China are well resolved and map directly to geologic provinces. Regions with the lowest attenuation （high Q₀ values） are beneath the Tarim Basin, Sichuan Basin, Ordos Platform, and South China Block. These tend to be tectonically inactive regions that are generally dominated by intrusive and cratonic rocks in the upper crust. Regions with the highest attenuation （low Q₀ values） are beneath Bohai Basin, Sichuan-Yunnan, North China basin, and regions beneath the Tian Shan, Qilian Shan and Fenwei graben also have low Q₀ values. These are predominantly active basins and fold belts.更多还原