地震研究

根据重庆及周边地区固定地震台站记录的远震资料提取了接收函数,并利用接收函数Pms相到时方差最小方法建立网格搜索,最终获得该区的地壳各向异性参数。结果表明:重庆及周边地区的地壳各向异性延迟时间为0.14～0.91 s,平均为0.4 s; 快波偏振方向主要有NEE、NNW和NWW向,并且大部分台站快波方向与所在区域的主压应力方向明显不一致; 重庆地区地壳各向异性具有横向不均匀性及分区特征,岩石圈形变特征主要来自地幔各向异性。

In this paper,a receiver function is extracted from the teleseismic data recorded by the seismic network and earthquake stations in Chongqing and its surrounding areas,and a grid search is established by using the minimum variance of arrival time of Pms phase of the receiver function.Finally anisotropic parameters of the crust are obtained.The results indicate that the delay time of the crustal anisotropic in Chongqing and its surrounding areas is ranges within 0.14～0.91 s,with an average of 0.4 s; The fast wave mainly polarizes in NEE,NNW,and NWW directions,and the direction of the fast wave at most of the stations is obviously different from the direction of the main compressive stress in the study area.And in this area the anisotropy of the crust features transverse heterogeneity and zoning; the characteristics of lithospheric deformation are mainly derived from mantle anisotropy.

引言
1 数据和方法
2 研究结果
3 讨论
4 结论

图1 重庆及周边地区断裂及地震台站分布<br/>Fig.1 Distribution of faults in Chongqing and its surrouding area and locations of the seismic stations used in study

图1 重庆及周边地区断裂及地震台站分布
Fig.1 Distribution of faults in Chongqing and its surrouding area and locations of the seismic stations used in study

图2 本文所选取的地震事件分布<br/>Fig.2 Locations of the earthquakes used in study

图2 本文所选取的地震事件分布
Fig.2 Locations of the earthquakes used in study

图3 利用远震波形计算ROC台的接收函数<br/>Fig.3 Calculation of receiver function at ROC station by using teleseismic waveform

图3 利用远震波形计算ROC台的接收函数
Fig.3 Calculation of receiver function at ROC station by using teleseismic waveform

图4 ROC台Pms震相到时拟合结果<br/>Fig.4 The fitting result of arrival time of Pms phase at ROC station

图4 ROC台Pms震相到时拟合结果
Fig.4 The fitting result of arrival time of Pms phase at ROC station

图5 WAS台Pms相到时拟合结果<br/>Fig.5 The fitting result of arrival time of Pms phase at ROC station[HT]

图5 WAS台Pms相到时拟合结果
Fig.5 The fitting result of arrival time of Pms phase at ROC station[HT]

图6 重庆及周边地区地壳各向异性和SKS分裂获取的各向异性结果对比(断裂同图1)<br/>Fig.6 Crustal anisotropy in Chongqing and its surrounding area and anisotropic results obtained by SKS phase splitting (faults is sameas in Fig.1)

图6 重庆及周边地区地壳各向异性和SKS分裂获取的各向异性结果对比(断裂同图1)
Fig.6 Crustal anisotropy in Chongqing and its surrounding area and anisotropic results obtained by SKS phase splitting (faults is sameas in Fig.1)

表1 重庆及周边地区地震台站下方地壳各向异性计算结果<br/>Tab.1 Calculated results of crustal anisotropy beneath seismic stations in Chongqing and its surrounding area

表1 重庆及周边地区地震台站下方地壳各向异性计算结果
Tab.1 Calculated results of crustal anisotropy beneath seismic stations in Chongqing and its surrounding area

图7 重庆不同构造分区快波方向等面积玫瑰投影图<br/>Fig.7 Equal-area rose projection of fast wave's direction of Chongqing structural block

图7 重庆不同构造分区快波方向等面积玫瑰投影图
Fig.7 Equal-area rose projection of fast wave's direction of Chongqing structural block

常利军,王椿镛,丁志峰.2008.四川及邻区上地幔各向异性研究[J].中国科学,38(12):1589-1599.
陈涛,张锐,黄世源.2018.三峡重庆地区形变场及构造应力场研究[J].大地测量与地球动力学,38(2):129-132.
丁仁杰,李克昌.2004.重庆地震研究[M].北京:地震出版社.
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.
韩明,李建有,徐晓雅,等.2017.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,60(12):4537-4556.
贺曼秋,魏红梅,章静,等.2008.荣昌台S波分裂研究[J].内陆地震,22(1):84-88.
李翠平,唐茂云,郭卫英,等.2019.2017年11月23日重庆武隆MS5.0地震序列重定位及发震断层分析[J].地震地质,41(3):603-618.
强正阳,吴庆举,李永华,等.2016.蒙古中南部地区地壳各向异性及其动力学意义[J].地球物理学报,59(5):1616-1628.
邵若潼,沈旭章,张元生.2019.青藏高原东北缘甘东南地区地壳各向异性特征及构造意义[J].地球物理学报,62(9):3340-3353.
孙长青,陈贇,高尔根.2011.青藏高原东缘强烈盆山相互作用区的地壳各向异性特征及其动力学意义探讨[J].地球物理学报,54(5):1205-1214.
孙长青,雷建设,李聪,等.2013.云南地区地壳各向异性及其动力学意义[J].地球物理学报,56(12):4095-4105.
姚陈,郝重涛,张广利.2016.SKS波对地壳裂隙各向异性的响应——理论地震图研究[J].地球物理学报,59(7):2498-2509.
佐佳卉,钮凤林.2019.利用多层横波各向异性测量方法计算两层介质的分裂参数[J].地球物理学报,62(8):2885-2898.
Chen Y,Zhang Z,Sun C,et al,2013.Crustal anisotropy from Moho converted Ps wave splitting analysis and geodynamic implications beneath the eastern margin of Tibet and surrounding regions[J].Gondwana Research,24(3-4):946-957.
Crampin S,Atkinson B K.1985.Microcracks in the Earth's crust[J].First Break,3(3):16-20.
Crampin S,Gao Y.2014.Two species of microcracks[J].Applied Geophysics,11(1):1-8.
Crampin S,Peacock S.2005.A review of shear-wave splitting in the compliant crack-critical anisotropic Earth[J].Wave Motion,41(1):59-77.
Kong F S,Wu J,Liu K H,et al.2016.Crustal anisotropy and ductile flow beneath the eastern Tibetan Plateau and adjacent areas[J].Earth and Planetary Science Letters,442(10):72-79.
Liu H,Niu F,2012.Estimating crustal seismic anisotropy with a joint analysis of radialand transverse receiver function data[J].Geophys J Int,188(1):144-164.
Rumpker G,Kaviani A,Latifi K.2014.Ps-splitting analysis for multilayered anisotropic media by azimuth al stacking and layer stripping[J].Geophys J Int,199(1):146-163.
Sun Y,Niu F,Liu H,et al.2012.Crustal structure and deformation of the SE Tibet an plateau revealed by receiver function data[J].Earth and Planetary Science Letters.349-350(17):186-197.
Vinnik L P,Montagner J P.1996.Shear wave splitting in the mantle Ps phases[J].Geophysical Research Letters,23(18):2449-2452.

备注

引言

1 数据和方法

2 研究结果

3 讨论

4 结论

期刊信息