Shallow shear wave velocity structure and azimuthal anisotropy in Yibin，Sichuan
-
摘要: 利用四川宜宾及周边地区布设的30个临时台站连续44天的波形记录，采用背景噪声互相关方法提取了周期为1—15 s的瑞雷面波相速度频散曲线，然后使用基于面波射线路径追踪的瑞雷面波直接成像方法得到0—10 km深度范围内三维S波速度模型，最后利用该模型作为初始模型采用相同的反演框架得到该地区的方位各向异性结构. 结果表明：浅层S波波速横向分布不均匀，随着深度增加呈不均一性减弱，在2 km深度左右，筠连—高县—珙县—长宁背斜一带的S波速度呈高速分布，可能与该区域地层经历褶皱、抬升和地表风化剥蚀有关；从5 km深度起，随着深度增加狮子滩—双河场—长宁背斜区域的S波速度在西北部较东南部相对较低，而低速的分布反映出区域内介质力学性质较弱，因此可能是2019年长宁地震序列沿近北西向破裂的原因之一。方位各向异性结果表明: 在孔滩背斜附近，快波方向与背斜走向近似平行，随着深度增加各向异性强度变弱，而且快波方向逐渐向北收敛向西南撒开，呈帚状分布；在区域地质构造作用、主压应力场等的共同影响下，局部区域的方位各向异性快波方向在不同深度处呈现出复杂的特征。Abstract: Based on the 44-day continuous waveform data recorded by 30 temporary stations in Yibin and its adjacent regions, Rayleigh wave phase velocity dispersion curves in the period range 1−15 s are extracted by using the ambient noise cross-correlation method. Then the direct surface wave tomographic method with period-dependent ray tracing is applied to obtain the 3-D shear-wave velocity structure. Finally, by taking the inverted shear-wave velocity model as the initial model, we obtained the azimuthal anisotropic structure in the same inversion framework. The results show that the distribution of shallow shear-wave velocity is heterogeneous, and the degree of heterogeneity decreases with the depth. At about 2 km depth, high velocity is distributed beneath the Junlian-Gaoxian-Gongxian-Changning anticline, which may be related to the folding, uplift, weathering and denudation of the strata in this area. The northwest of Shizitan-Shuanghechang-Changning anticline shows relatively low velocity compared with the southeast with a depth deeper than 5 km. As we known, the medium with relatively low wave velocity are usually weaker compared with high velocity, so it may be one of the reasons for the northwestward rupture of the Changning earthquake sequence in 2019. Our results of azimuthal anisotropy show that near the Kongtan anticline, the fast wave direction is approximately parallel to the strike of the anticline, and the anisotropic strength becomes weaker with the increase of depth.We also found that the fast wave direction gradually converges to the north and spreads to the south, showing a brush-type structure. Under the influence of regional geological structure and stress field, the fast wave directions in some local areas show complex characteristics at different depths.
-
-
![]()
图 1 四川宜宾地区构造及地震和台站分布
Figure 1. The topography of the Yibin area and distribution of earthquakes and stations
![]()
图 2 1—15 s周期的台站对之间的互相关函数（a）和基阶瑞雷面波相速度频散曲线（b）
Figure 2. nterstation cross-correlation function （a） and The fundamental Rayleigh wave phase velocity dispersion curves （b） in the 1−15 s period
![]()
图 3 基阶瑞雷面波相速度频散的深度敏感核
Figure 3. Depth sensitivity kernels for the fundamental Rayleigh wave phase velocity dispersion at different periods
![]()
图 4 2 km （a）和6 km （b）深度处的横向和纵向剪切波速棋盘测试结果
左图为初始模型，右图为对应的恢复结果。三角形为台站位置，灰色阴影为地形
Figure 4. Lateral and vertical shear-wave velocity checkerboard tests at the depths of 2 km （a） and 6 km （b）
The left panels are the initial models and the right ones are the corresponding recovery results. The location of the station and topography are shown as triangle and gray shadow，respectively
![]()
图 5 方位各向异性棋盘测试的输入（a）和输出（b）结果
Figure 5. Checkerboard tests input （a） and output （b） results of azimuthal anisotropy
![]()
图 6 研究区内深度为2 km （a），4 km （b），6 km （c）和10 km （d）的三维S波速度结构
Figure 6. 3D shear wave velocity structures at the depths of 2 km （a），4 km （b），6 km （c） and 10 km （d） beneath the study area
![]()
图 8 不同深度范围的三维S波速度模型及方位各向异性
Figure 8. Three-dimensional shear wave speed model and corresponding azimuthal anisotropy in different depth ranges
![]()
图 7 AA′和BB′剖面 0—10 km深度范围内的S波速度结构
（a） 5 km深度的S波速度图像，其中黑线剖面位置；（b） AA′剖面；（c） BB′剖面
Figure 7. Shear wave structures of the profiles AA′ and BB′ in the depth range of 0−10 km
（a） vS structure at the depth of 5 km，the black lines respent the location of profiles；（b） AA′ profile；（c） BB′ profile
-
高原,石玉涛,王琼. 2020. 青藏高原东南缘地震各向异性及其深部构造意义[J]. 地球物理学报,63(3):802–816. doi: 10.6038/cjg2020O0003 Gao Y,Shi Y T,Wang Q. 2020. Seismic anisotropy in the southeastern margin of the Tibetan Plateau and its deep tectonic significances[J]. Chinese Journal of Geophysics,63(3):802–816 (in Chinese).
何登发,鲁人齐,黄涵宇,王晓山,姜华,张伟康. 2019. 长宁页岩气开发区地震的构造地质背景[J]. 石油勘探与开发,46(5):993–1006. He D F,Lu R Q,Huang H Y,Wang X S,Jiang H,Zhang W K. 2019. Tectonic and geological background of the earthquake hazards in Changning shale gas development zone,Sichuan basin,SW China[J]. Petroleum Exploration and Development,46(5):993–1006 (in Chinese).
何玉林,韩小平,戈天勇,李军,何锡明,王辉. 2004. 2004年6月17日四川宜宾4.5级地震烈度考察及灾害损失评估[J]. 四川地震,(4):17–24. doi: 10.3969/j.issn.1001-8115.2004.04.004 He Y L,Han X P,Ge T Y,Li J,He X M,Wang H. 2004. Intensity distribution and earthquake disaster assessment of Yibin M4.5 earthquake on 17 June 2004[J]. Earthquake Research in Sichuan,(4):17–24 (in Chinese).
胡幸平,崔效锋,张广伟,王甘娇,Arno Zang,史丙新,姜大伟.胡幸平,崔效锋,张广伟,王甘娇,Arno Zang,史丙新,姜大伟 2021. 长宁地区复杂地震活动的力学成因分析[J]. 地球物理学报,64(1):1–17. Hu X P, Cui X F,Zhang G W,Wang G J,Arno Z,Shi B X, Jiang D W. 2021. Analysis on the mechanical causes of the complex seismicity in Changning area, China[J]. Chinese Journal of Geophysics,64(1):1–17 (in Chinese).
阚荣举,张四昌,晏凤桐,俞林胜. 1977. 我国西南地区现代构造应力场与现代构造活动特征的探讨[J]. 地球物理学报,20(2):96–109. Kan R J,Zhang S C,Yan F T,Yu L S. 1977. Present tectonic stress field and its relation to the characteristics of recent tectonic activity in southwestern China[J]. Acta Geophysica Sinica,20(2):96–109 (in Chinese).
雷霆. 2020. 济南市背景噪声成像: 地下水运移与地热水的形成[D]. 合肥: 中国科学技术大学: 39–45. Lei T. 2020. Ambient Noise Tomography of Ji’nan: The Migration of Groundwater and the Formation of Geothermal Water[D]. Hefei: University of Science and Technology of China: 39–45 （in Chinese）.
李大虎,詹艳,丁志峰,高家乙,吴萍萍,孟令媛,孙翔宇,张旭. 2021. 四川长宁MS6.0地震震区上地壳速度结构特征与孕震环境[J]. 地球物理学报,64(1):18–35. doi: 10.6038/cjg2021O0241 Li D H,Zhan Y,Ding Z F,Gao J Y,Wu P P,Meng L Y,Sun X Y,Zhang X. 2021. Upper crustal velocity and seismogenic environment of the Changning MS6.0 earthquake region in Sichuan,China[J]. Chinese Journal of Geophysics,64(1):18–35 (in Chinese).
刘成明. 2005. 宜宾北4.7级地震活动背景、特征及其与鲁甸5.6级强震呼应成因分析[J]. 地震地磁观测与研究,6(5):24–32. doi: 10.3969/j.issn.1003-3246.2005.05.004 Liu C M. 2005. The analysis to seismic activity background,features and its related to M5.6 Ludian strong earthquake for the M4.7 Yibin earthquake[J]. Seismological and Geomagnetic Observation and Research,6(5):24–32 (in Chinese).
商咏梅. 2018. 青藏高原东南缘岩石圈变形特征及各向异性成因分析[D]. 北京: 中国地震局地质研究所: 6–23. Shang Y M. 2018. Analysis of Deformation and Anisotropy of the Lithosphere in SE Tibetan Plateau[D]. Beijing: Institute of Geology, China Earthquake Administrator: 6–23 （in Chinese）.
宋晓东,李江涛,鲍学伟,李思田,王良书,任建业. 2015. 中国西部大型盆地的深部结构及对盆地形成和演化的意义[J]. 地学前缘,22(1):126–136. Song X D,Li J T,Bao X W,Li S T,Wang L S,Ren J Y. 2015. Deep structure of major basins in western China and implications for basin formation and evolution[J]. Earth Science Frontiers,22(1):126–136 (in Chinese).
孙权,裴顺平,苏金蓉,刘雁冰,薛晓添,李佳蔚,李磊,左洪. 2021. 2019年6月17日四川长宁MS6.0地震震源区三维速度结构[J]. 地球物理学报,64(1):36–53. doi: 10.6038/cjg2021O0246 Sun Q,Pei S P,Su J R,Liu Y B,Xue X T,Li J W,Li L,Zuo H. 2021. Three-dimensional seismic velocity structure across the 17 June 2019 Changning MS6.0 earthquake,Sichuan,China[J]. Chinese Journal of Geophysics,64(1):36–53 (in Chinese).
滕吉文,张永谦,阮小敏,胡国泽,闫雅芬. 2012. 地球内部壳幔介质地震各向异性与动力学响应[J]. 地球物理学报,55(11):3648–3670. doi: 10.6038/j.issn.0001-5733.2012.11.013 Teng J W,Zhang Y Q,Ruan X M,Hu G Z,Yan Y F. 2012. The seismic anisotropy of the crustal and mantle medium of the Earth interior and its dynamical response[J]. Chinese Journal of Geophysics,55(11):3648–3670 (in Chinese).
王琼,高原,石玉涛,吴晶. 2013. 青藏高原东北缘上地幔地震各向异性:来自SKS、PKS和SKKS震相分裂的证据[J]. 地球物理学报,56(3):892–905. doi: 10.6038/cjg20130318 Wang Q,Gao Y,Shi Y T,Wu J. 2013. Seismic anisotropy in the uppermost mantle beneath the northeastern margin of Qinghai-Tibet Plateau:Evidence from shear wave splitting of SKS,PKS and SKKS[J]. Chinese Journal of Geophysics,56(3):892–905 (in Chinese).
杨跃明,陈玉龙,刘燊阳,邓宾,徐浩,陈丽清,黎丁源,殷樱子,李怡. 2021. 四川盆地及其周缘页岩气勘探开发现状、潜力与展望[J]. 天然气工业,41(1):42–58. Yang Y M,Chen Y L,Liu S Y,Deng B,Xu H,Chen L Q,Li D Y,Yin Y Z,Li Y. 2021. Status,potential and prospect of shale gas exploration and development in the Sichuan Basin and its periphery[J]. Natural Gas Industry,41(1):42–58 (in Chinese).
易桂喜,龙锋,梁明剑,赵敏,王思维,宫悦,乔慧珍,苏金蓉. 2019. 2019年6月17日四川长宁MS6.0地震序列震源机制解与发震构造分析[J]. 地球物理学报,62(9):3432–3447. doi: 10.6038/cjg2019N0297 Yi G X,Long F,Liang M J,Zhao M,Wang S W,Gong Y,Qiao H Z,Su J R. 2019. Focal mechanism solutions and seismogenic structure of the 17 June 2019 MS6.0 Sichuan Changning earthquake sequence[J]. Chinese Journal of Geophysics,62(9):3432–3447 (in Chinese).
曾求,储日升,盛敏汉,危自根. 2020. 基于地震背景噪声的四川威远地区浅层速度结构成像研究[J]. 地球物理学报,63(3):944–955. doi: 10.6038/cjg2020N0177 Zeng Q,Chu R S,Sheng M H,Wei Z G. 2020. Seismic ambient noise tomography for shallow velocity structures beneath Weiyuan,Sichuan[J]. Chinese Journal of Geophysics,63(3):944–955 (in Chinese).
张国苓,杨晓松,陈建业,闫小兵. 2010. 中下地壳岩石弹性波各向异性的影响因素[J]. 地震地质,32(2):327–337. doi: 10.3969/j.issn.0253-4967.2010.02.016 Zhang G L,Yang X S,Chen J Y,Yan X B. 2010. The influencing factor of elastic anisotropy in middle to lower continental crust[J]. Seismology and Geology,32(2):327–337 (in Chinese).
张致伟,龙锋,王世元,宫悦,吴朋,王辉,汪国茂. 2019. 四川宜宾地区地震定位及速度结构[J]. 地震地质,41(4):913–926. doi: 10.3969/j.issn.0253-4967.2019.04.007 Zhang Z W,Long F,Wang S Y,Gong Y,Wu P,Wang H,Wang G M. 2019. Earthquake location and velocity structure in Yibin area,Sichuan[J]. Seismology and Geology,41(4):913–926 (in Chinese).
Bao X W,Eaton D W. 2016. Fault activation by hydraulic fracturing in western Canada[J]. Science,354(6318):1406–1409. doi: 10.1126/science.aag2583
Bensen G D,Ritzwoller M H,Barmin M P,Levshin A L,Lin F,Moschetti M P,Shapiro N M,Yang Y. 2007. Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements[J]. Geophys J Int,169(3):1239–1260. doi: 10.1111/j.1365-246X.2007.03374.x
Boness N L,Zoback M D. 2004. Stress-induced seismic velocity anisotropy and physical properties in the SAFOD pilot hole in Parkfield,CA[J]. Geophys Res Lett,31(15):L15S17.
Boness N L,Zoback M D. 2006. A multiscale study of the mechanisms controlling shear velocity anisotropy in the San Andreas fault observatory at depth[J]. Geophysics,71(5):F131–F146. doi: 10.1190/1.2231107
Crampin S,Chastin S. 2003. A review of shear wave splitting in the crack-critical crust[J]. Geophys J Int,155(1):221–240. doi: 10.1046/j.1365-246X.2003.02037.x
Fang H J,Yao H J,Zhang H J,Huang Y C,van der Hilst R D. 2015. Direct inversion of surface wave dispersion for three-dimensional shallow crustal structure based on ray tracing:Methodology and application[J]. Geophys J Int,201(3):1251–1263. doi: 10.1093/gji/ggv080
Feng J K,Yao H J,Wang Y,Poli P,Mao Z. 2021. Segregated oceanic crust trapped at the bottom mantle transition zone revealed from ambient noise interferometry[J]. Nat Commun,12:2531. doi: 10.1038/s41467-021-22853-2
Gao Y,Wu J,Fukao Y,Shi Y T,Zhu A L. 2011. Shear wave splitting in the crust in North China:Stress,faults and tectonic implications[J]. Geophys J Int,187(2):642–654. doi: 10.1111/j.1365-246X.2011.05200.x
Lei X L,Wang Z W,Su J R. 2019a. The December 2018 ML5.7 and January 2019 ML5.3 earthquakes in South Sichuan basin induced by shale gas hydraulic fracturing[J]. Seismol Res Lett,90(3):1099–1110. doi: 10.1785/0220190029
Lei X L,Wang Z W,Su J R. 2019b. Possible link between long-term and short-term water injections and earthquakes in salt mine and shale gas site in Changning,south Sichuan Basin,China[J]. Earth Planet Phys,3(6):510–525. doi: 10.26464/epp2019052
Lei J S, Li Y, Xie F R, Teng J W, Zhang G W, Sun C Q, Zha X H. 2014. Pn anisotropic tomography and dynamics under eastern Tibetan Plateau[J]. J Geophy Res:Solid Earth,119(3):2174–2198.
Liang C T,Liu Z Q,Hua Q,Wang L,Jiang N B,Wu J. 2020. The 3D seismic azimuthal anisotropies and velocities in the eastern Tibetan Plateau extracted by an azimuth-dependent dispersion curve inversion method[J]. Tectonics,39(4):e2019TC005747.
Lin F C,Ritzwoller M H,Yang Y J,Moschetti M P,Fouch M J. 2011. Complex and variable crustal and uppermost mantle seismic anisotropy in the western United States[J]. Nat Geosci,4(1):55–61. doi: 10.1038/ngeo1036
Liu C M,Yao H J,Yang H Y,Shen W S,Fang H J,Hu S Q,Qiao L. 2019. Direct inversion for three-dimensional shear wave speed azimuthal anisotropy based on surface wave Ray-tracing:Methodology and application to Yunnan,Southwest China[J]. J Geophys Res:Solid Earth,124(11):11394–11413. doi: 10.1029/2018JB016920
Liu Q Y,Van Der Hilst R D,Li Y,Yao H J,Chen J H,Guo B,Qi S H,Wang J,Huang H,Li S C. 2014. Eastward expansion of the Tibetan Plateau by crustal flow and strain partitioning across faults[J]. Nat Geosci,7(5):361–365. doi: 10.1038/ngeo2130
Long F,Zhang Z W,Qi Y P,Liang M J,Ruan X,Wu W W,Jiang G M,Zhou L Q. 2020. Three dimensional velocity structure and accurate earthquake location in Changning-Gongxian area of southeast Sichuan[J]. Earth Planet Phys,4(2):163–177.
Luo S,Yao H J,Wang J N,Wang K D,Liu B. 2021. Direct inversion of surface wave dispersion data with multiple-grid parametrizations and its application to a dense array in Chao Lake,eastern China[J]. Geophys J Int,225(2):1432–1452. doi: 10.1093/gji/ggab036
Luo S,Yao H J. 2021. Multistage tectonic evolution of the Tanlu fault:Insights from upper crustal azimuthal anisotropy of the Chao Lake segment[J]. Tectonophysics,806:228795. doi: 10.1016/j.tecto.2021.228795
Moschetti M P,Ritzwoller M H,Lin F,Yang Y. 2010. Seismic evidence for widespread western-US deep-crustal deformation caused by extension[J]. Nature,464(7290):885–889. doi: 10.1038/nature08951
Rawlinson N, Sambridge M. 2004. Wave front evolution in strongly heterogeneous layered media using the fast marching method[J]. Geophys J Int,156(3).
Sayers C. M 1999. Stress-dependent seismic anisotropy of shales[J]. Geophysics,64(1):93–98. doi: 10.1190/1.1444535
Segall P. 1989. Earthquakes triggered by fluid extraction[J]. Geology,17(10):942–946. doi: 10.1130/0091-7613(1989)017<0942:ETBFE>2.3.CO;2
Shapiro N M,Campillo M,Stehly L,Ritzwoller M H. 2005. High-resolution surface-wave tomography from ambient seismic noise[J]. Science,307(5715):1615–1618. doi: 10.1126/science.1108339
Shen W S, Ritzwoller M H, Kang D, Kim Y H, Lin F C, Ning J Y, Wang W T, Zheng Y, Zhou L Q. 2016. A seismic reference model for the crust and uppermost mantle beneath China from surface wave dispersion[J]. Geophys J Int,206(2):954–979.
Tan Y Y,Hu J,Zhang H J,Chen Y K,Qian J W,Wang Q F,Zha H S,Tang P,Nie Z. 2020. Hydraulic fracturing induced seismicity in the southern Sichuan basin due to fluid diffusion inferred from seismic and injection data analysis[J]. Geophys Res Lett,47(4):e2019GL084885.
Wang Q,Niu F L,Gao Y,Chen Y T. 2016. Crustal structure and deformation beneath the NE margin of the Tibetan Plateau constrained by teleseismic receiver function data[J]. Geophys J Int,204(1):167–179. doi: 10.1093/gji/ggv420
Weiss T, Siegesmund S, Rabbel W, Bohlen T, Pohl M. 1999. Seismic velocities and anisotropy of the lower continental crust: A review[G]//Seismic Exploration of the Deep Continental Crust. Basel: Birkhäuser.
Yang X,Yao H J,Hang B S. 2021. Crustal footprint of mantle upwelling and plate amalgamation revealed by ambient noise tomography in northern Vietnam and the northern South China Sea[J]. J Geophys Res:Solid Earth,126(2):e2020JB020593.
Yao H J,van der Hilst R D,de Hoop M V. 2006. Surface-wave array tomography in SE Tibet from ambient seismic noise and two-station analysis: Ⅰ . Phase velocity maps[J]. Geophys J Int,166(2):732–744. doi: 10.1111/j.1365-246X.2006.03028.x
Yao H J,Beghein C,van der Hilst R D. 2008. Surface wave array tomography in SE Tibet from ambient seismic noise and two-station analysis: Ⅱ . Crustal and upper-mantle structure[J]. Geophys J Int,173(1):205–219. doi: 10.1111/j.1365-246X.2007.03696.x
Yao H J,van der Hilst R D,Montagner J P. 2010. Heterogeneity and anisotropy of the lithosphere of SE Tibet from surface wave array tomography[J]. J Geophy Res:Solid Earth,115(B12):B12307. doi: 10.1029/2009JB007142
Yao H J, Gouedard P,Collins J A, McGuire J J, van der Hilst R D. 2011. Structure of young East Pacific rise lithosphere from ambient noise correlation analysis of fundamental and higher-mode Scholte-Rayleigh waves[J]. Comptes Rendus Geosci,343:571–583.
Zang A,Zimmermann G,Hofmann H,Stephansson O,Min K B,Kim K Y. 2019. How to reduce fluid-injection-induced seismicity[J]. Rock Mech Rock Eng,52(2):475–493. doi: 10.1007/s00603-018-1467-4
Zhang H J,Thurber C H. 2003. Double-difference tomography:The method and its application to the Hayward fault,California[J]. Bull Seismol Soc Am,93(5):1875–1889. doi: 10.1785/0120020190
Zhang Z,Teng J,Badal J,Liu E. 2009. Construction of regional and local seismic anisotropic structures from wide-angle seismic data:Crustal deformation in the southeast of China[J]. J Seismol,13(2):241–252. doi: 10.1007/s10950-008-9124-0
下载:
计量
- 文章访问数: 777
- HTML全文浏览量: 355
- PDF下载量: 99
