倾斜界面和各向异性对谐波分解方法的影响研究

doi:10.12196/j.issn.1000-3274.2022.01.007

摘要/Abstract

摘要： 利用接收函数谐波分解方法可以提取地壳下方的不均匀信息, 但当多种不均匀性同时存在时, 该方法反演结果的准确性目前尚不十分清楚。基于5组20个理论模型, 研究了倾斜界面和各向异性对谐波分解方法的影响。结果表明, 对于只存在倾斜界面的情况, 利用谐波分解方法可以很好地得到模型参数。在各向异性和倾斜界面同时存在的情况下, 各向异性的存在会影响谐波分解得到的倾斜界面振幅信息, 而且这种影响还和倾斜界面的走向有关。倾斜轴各向异性谐波分解得到的各向异性强度与倾斜轴倾角大小有关, 与快轴方向关系不大。使用谐波分解方法对江西九江台进行分析, 结果表明, 台站下方倾斜和各向异性共存, 快轴方向约为86°, 时间延迟约为0.46 s。

关键词: 各向异性, 倾斜界面, 谐波分解, 接收函数

Abstract: The receiver function harmonic decomposition method can extract the inhomogeneous information under the crust, but when many kinds of inhomogeneities exist at the same time, the accuracy of the inversion results of this method is not very clear at present. Based on five groups of 20 theoretical models, the influence of inclined interface and anisotropy on the method of harmonic decomposition is studied. The results show that the harmonic decomposition method can get the model parameters well for the case of inclined interface only. When anisotropy and inclined interface exist at the same time, the existence of anisotropy will affect the amplitude information of inclined interface obtained by harmonic decomposition, and the influence is also related to the direction of inclined interface. The strength of anisotropy obtained by anisotropic harmonic decomposition of tilt axis is related to the dip angle of tilt axis, while the direction of fast axis has little effect. The harmonic decomposition method is used to analyze the Jiujiang station, Jiangxi, China. The results show that dipping interface and anisotropy coexist under the station, the fast axis direction is about 86 ° and the time delay is about 0.46 s.

Key words: Anisotropy, Dipping interface, Harmonic decomposition, Receiver function

中图分类号:

P315.7

查小惠. 倾斜界面和各向异性对谐波分解方法的影响研究[J]. 地震, 2022, 42(1): 99-110.

ZHA Xiao-hui. Study on the Influence of Inclined Interface and Anisotropy on the Method of Harmonic Decomposition[J]. EARTHQUAKE, 2022, 42(1): 99-110.

参考文献

[1] Owens T J, Zandt G, Taylor S R. Seismic evidence for an ancient rift beneath the Cumberland plateau, Tennessee: A detailed analysis of broadband teleseismic P waveforms[J]. Journal of Geophysical Research: Solid Earth, 1984, 89(B9): 7783-7795.
[2] 徐震, 徐鸣洁, 王良书, 等. 用接收函数Ps转换波研究地壳各向异性以哀牢山—红河断裂带为例[J]. 地球物理学报, 2006, 49(2): 438-448.
XU Zhen, XU Ming-jie, WANG Liang-shu, et al. A study on crustal anisotropy using P to S converted phase of the receiver function: Application to Ailaoshan—Red River fault zone[J]. Chinese Journal of Geophysics, 2006, 49(2): 438-448 (in Chinese).
[3] 强正阳, 吴庆举, 何静, 等. 内蒙古阿巴嘎地区地壳方位各向异性研究[J]. 地球物理学报, 2019, 62(8): 2946-2958.
QIANG Zheng-yang, WU Qing-ju, HE Jing, et al. Crustal azimuthal anisotropy beneath Abag area in Inner Mongolia, China[J]. Chinese Journal of Geophysics, 2019, 62(8): 2946-2958 (in Chinese).
[4] 杨妍, 姚华建, 张萍, 等. 用接收函数方法研究华北克拉通中部造山带及其邻域地壳方位各向异性[J]. 中国科学: 地球科学, 2018, 48(7): 912-923.
YANG Yan, YAO Hua-Jian, ZHANG Ping, et al. Crustal azimuthal anisotropy in the trans-North China orogen and adjacent regions from receiver functions[J]. Science China: Earth Sciences, 2018, 48(7): 912-923 (in Chinese).
[5] 韩明, 李建有, 徐晓雅, 等. 按方位叠加接收函数分析青藏高原东南缘的地壳各向异性[J]. 地球物理学报, 2017, 60(12): 4537-4556.
HAN Ming, LI Jian-you, XU Xiao-ya, et al. Analysis for crustal anisotropy beneath the southeastern margin of Tibet by stacking azimuthal receiver functions[J]. Chinese Journal of Geophysics, 2017, 60(12): 4537-4556 (in Chinese).
[6] Bianchi I, Park J, Piana Agostinetti N, et al. Mapping seismic anisotropy using harmonic decomposition of receiver functions: An application to Northern Apennines, Italy[J]. Journal Geophysical Research, 2010, 115: B12317.
[7] Rümpker G, Kaviani A, Latifi K. Ps-splitting analysis for multilayered anisotropic media by azimuthal stacking and layer stripping[J]. Geophysical Journal International, 2014, 199(1): 146-163.
[8] Liu H F, Niu F L. Estimating crustal seismic anisotropy with a joint analysis of radial and transverse receiver function data[J]. Geophysical Journal International, 2012, 188(1): 144-164.
[9] 王琼, 高原, 钮凤林, 等. 利用接收函数计算地壳各向异性的可靠性分析及倾斜界面的影响[J]. 地震, 2016, 36(2): 14-25.
WANG Qiong, GAO Yuan, NIU Feng-lin, et al. Reliability analysis of crustal anisotropy from receiver functions and effect of dipping interface[J]. Earthquake, 2016, 36(2): 14-25 (in Chinese).
[10] Sun Y, Niu F L, Liu H F, et al. Crustal structure and deformation of the SE Tibetan plateau revealed by receiver function data[J]. Earth and Planetary Science Letters, 2012, 349-350: 186-197.
[11] Frederiksen A W, Bostock M G. Modeling teleseismic waves in dipping anisotropic structure[J]. Geophysical Journal International, 2000, 141(2): 401-412.
[12] 查小惠, 孙长青, 李聪. 倾斜界面和各向异性地层对H-κ搜索结果的影响[J]. 地球物理学进展, 2013, 28(1): 121-131.
ZHA Xiao-hui, SUN Chang-qing, LI Cong. The effects of dipping interface and anisotropic layer on the result of H-κ method[J]. Progress in Geophysics, 2013, 28(1): 121-131 (in Chinese).
[13] Ligorría J P, Ammon C J. Iterative deconvolution and receiver-function estimation[J]. Bulletin of the Seismological Society of America, 1999, 89(5): 1395-1400.
[14] 杨晓瑜. 长江中下游成矿带及邻区上地幔各向异性研究[D]. 北京: 中国地质大学(北京), 2017.
YANG Xiao-yu. The upper mantle anisotropy beneath the middle-lower Yangtze metallogenic belt and adjacent regions[D]. Beijing: China University of Geosciences (Beijing), 2017 (in Chinese).
[15] 石玉燕, 郑斯华, 颜启, 等. 华东地区SKS波分裂研究[J]. 地震, 2012, 32(4): 33-43.
SHI Yu-yan, ZHENG Si-hua, YAN Qi, et al. SKS wave splitting in east China[J]. Earthquake, 2012, 32(4): 33-43 (in Chinese).