华南地震

基于各向异性介质下 Pms震相到时的理论公式和理论地层模型 ,验证了谐波分解方法求取地壳各向异性参数的可行性和可靠性。将该方法应用到余干地震台 ,发现余干地震台不同方位角接收函数 Pms震相存在明显的到时差,谐波分解结果表明台站下方各向异性快波方向约为 83°,时间延迟约为 0.28 s。快波方向和前人研究余干台的 SKS分裂结果较为一致 ,支持华南地区壳幔耦合变形的观点。水平轴各向异性模型参数只能部分解释 Pms到时差异完整的解释需要进一步考虑界面倾斜和倾斜轴各向异性等情况。

Based on the theoretical formula of the arrival time of the seismic phase of Pms in anisotropic medium and the theoretical stratigraphic model,the feasibility and reliability of the harmonic decomposition method to obtain the anisotropic parameters of the crust are verified. Applying this method to Yugan seismic station,it is found that there is obvious arrival time difference in different azimuth receiver functions of Pms phase in Yugan seismic station. The results of harmonic decomposition show that the direction of anisotropic fast wave under the station is about 83 ° and the time delay is about 0.28 s. The direction of the fast wave is consistent with the SKS splitting results of previous studies, which supports the viewpoint of crust mantle coupling deformation in South China. The parameters of horizontal axis anisotropic model can only partially explain the time difference of Pms, and the complete interpretation needs to further consider the interface tilt and tilt axis anisotropy.

引言
1 方法及理论测试
2 实际台站处理
3 结论和讨论

表1 harmfit函数4阶谐波分析结果<br/>Table 1 The fourth order harmonic analysis results of harmfit function

表1 harmfit函数4阶谐波分析结果
Table 1 The fourth order harmonic analysis results of harmfit function

图1 YUG地震台位置图<br/>Fig.1 Location map of YUG station

图1 YUG地震台位置图
Fig.1 Location map of YUG station

图2 理论和谐波拟合的Pms震相走时图<br/>Fig.2 Pms phase travel time diagram fitted with harmonics

图2 理论和谐波拟合的Pms震相走时图
Fig.2 Pms phase travel time diagram fitted with harmonics

表2 计算接收函数的地层模型<br/>Table 2 Strata models used for receiver function modeling

表2 计算接收函数的地层模型
Table 2 Strata models used for receiver function modeling

图3 A1模型Ps震相<br/>Fig.3 Ps phase of A1 model

图3 A1模型Ps震相
Fig.3 Ps phase of A1 model

图4 A1模型Ps震相对齐时差曲线<br/>Fig.4 Ps phase alignment time difference curve of A1 model

图4 A1模型Ps震相对齐时差曲线
Fig.4 Ps phase alignment time difference curve of A1 model

表3 模型A1和A2谐波分解结果<br/>Table 3 Harmonic decomposition results of model A1 and A2

表3 模型A1和A2谐波分解结果
Table 3 Harmonic decomposition results of model A1 and A2

表4 YUG台 2011—2019不同方位角接收函数数量<br/>Table 4 Number of receiver functions in different azimuths of YUG station from 2011 to 2019 bazF bazT NUM bazF bazT NUM bazF bazT NUM

表4 YUG台 2011—2019不同方位角接收函数数量
Table 4 Number of receiver functions in different azimuths of YUG station from 2011 to 2019 bazF bazT NUM bazF bazT NUM bazF bazT NUM

图5 2011—2019年远震震中分布图<br/>Fig.5 Epicenter distribution of teleseismic from 2011 to 2019

图5 2011—2019年远震震中分布图
Fig.5 Epicenter distribution of teleseismic from 2011 to 2019

图6 使用的地震事件震中分布图<br/>Fig.6 Epicenter distribution map of earthquakes used

图6 使用的地震事件震中分布图
Fig.6 Epicenter distribution map of earthquakes used

图7 余干台Ps震相<br/>Fig.7 Ps phase of YUG station

图7 余干台Ps震相
Fig.7 Ps phase of YUG station

图8 余干台Ps震相对齐时差曲线<br/>Fig.8 Ps phase alignment time difference curve of YUG station

图8 余干台Ps震相对齐时差曲线
Fig.8 Ps phase alignment time difference curve of YUG station

表5 余干台4阶谐波分解结果<br/>Table 5 The fourth order harmonic decomposition results of Yugan station

表5 余干台4阶谐波分解结果
Table 5 The fourth order harmonic decomposition results of Yugan station

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备注

引言

1 方法及理论测试

2 实际台站处理

3 结论和讨论

期刊信息