青藏高原东部Love波偏振研究  

Off-great circle propagation of Love waves in eastern Qinghai-Xizang Plateau

作　　者：郑月军[1] 黄忠贤[1] 刘建华[2] 胥颐[2] 

机构地区：[1]中国地震局地壳应力研究所,北京100085 [2]中国科学院地质与地球物理研究所,北京100029

出　　处：《地球物理学报》2006年第4期1068-1073,共6页Chinese Journal of Geophysics

基　　金：国家自然科学基金(40034010;40274010);地震联合基金(105110)资助

摘　　要：利用布设在云南西部的50个流动观测台站记录的三分量数字面波资料,采用频率域奇异值分解法,分析了中短周期Love波在青藏高原东部传播中的偏振状况.结果显示Love波的传播呈现明显的有规律的偏离大圆路径的异常,地壳-上地幔速度结构显著的横向不均匀性可能是造成这些偏振异常的主要原因.同时利用以前研究中得到的剪切波速度模型计算了Love波到达台站的理论偏离情况,大多数理论计算与实际观测结果的偏离方向基本一致,但理论偏离角通常小于观测值.这样的结果在一定程度上验证了所采用的青藏高原速度结构模型是基本正确的,同时也说明了模型对研究区域复杂的速度结构的反映还不够精细.The data of three-component digital surface wave from 50 portable seismograph stations located in west Yunnan, China, were collected and analyzed in this study. A frequency domain singular value decomposition method was used for polarization analysis ; and the polarizations of intermediate period Love waves traveling through the Qinghai-Xizang Plateau were calculated and evaluated. The result shows that there are obvious polarization anomalies, which could be due to the lateral heterogeneity of the lower crust and uppermost mantle velocity structure in the wave propagation path. Besides, theoretical arrival azimuths were computed by using the velocity model from a previous tomographic study. There is general consistency between the theoretical result and the majority of the observations, though the theoretical anomalies are often smaller than the observations. The result of present study indicates the correctness of our velocity model, as well as the complexity of the lithosphere in this area which is not fully reflected in the model.

关 键 词：青藏高原 Love波偏振 地壳上地幔速度结构 

分 类 号：P315[天文地球—地震学]