Refined techniques for data processing and two-dimensional inversion in magnetotelluric (Ⅶ): Electrical structure and seismogenic environment of Yingjiang-Longling seismic area
-
摘要:
本文对一条布设在滇西盈江-龙陵地区的大地电磁剖面（苏典-中山剖面）数据进行了精细处理和二维反演解释，得到了测区较高置信度的二维电性结构.该电性模型纵向上表现为高阻-低阻-高阻的"三明治"式岩石圈电性结构，上地壳为平均厚度约为10 km的高阻地层，在约6~16 km地壳深度范围发育有电阻率为几欧姆米的显著高导层，下地壳底部和上地幔顶部表现为电性较为均匀的相对高阻层.横向上自西向东划分出以大盈江断裂带、龙陵-瑞丽断裂带为限的3个主要构造区域.壳内分布的高导层沿剖面表现出一定的横向不均匀性，其在龙陵-瑞丽断裂带下方消失，在该处形成了腾冲地块和保山地块的电性构造边界.电性结构表明，大盈江断裂附近高导层顶界面浅，两侧高阻体厚度小，因此难以形成较大规模的相互作用，致其附近浅震源、小震级的地震活跃；龙陵-瑞丽断裂两侧的高阻体较厚，易积累较大的应力，具有大震的深部孕震环境，故其附近发生过多次7级以上强震.
Abstract:A 2D Magnetotelluric (MT) profile (Sudian-Zhongshan MT profile) located at Yingjiang-Longling area, western Yunnan, has been interpreted in refined processing techniques, and results in a robust two-dimensional resistivity model. Characterized by an electrical "sandwich" structure, this model consists of a resistive layer with mean thickness of 10 km in the upper crust, and an obvious high conductive layer in the depth of 6~16 km, under which is the relative resistive and homogeneous lower crust and uppermost mantle. Deduced from the resistivity model, this region was divided into three micro-tectonic elements bounded by the Dayingjiang fault and the Longling-Ruili fault respectively from west to east along the MT profile. The distribution of mid-crustal conductive layer shows somehow lateral heterogeneity, which disappears beneath the Longling-Ruili fault. Therefore, the Longling-Ruili fault acts as the electrical tectonic boundary between the Tengchong block and Baoshan block. Our model shows that the top surface of the high conductive layer under the Dayingjiang fault is very shallow, where the bilateral resistive rock of the fault is too thin to accumulate tectonic stress of huge magnitude earthquake hence resulting in active seismicity of shallow and small magnitude earthquakes. However, the thick resistive rock on both sides of the Longling-Ruili fault, which could act as effective mechanical carrier and amass huge tectonic stress, indicates the seismogenic electrical structure of several large earthquakes above magnitude 7 occurred nearby.
-
-
图 2
观测坐标系下所有测点观测曲线的叠加显示图
Figure 2.
Superimposed display of observed apparent resistivity and impedance phase curves in the observed coordinate system
图 3
多测点-多频点的电性主轴统计成像结果
Figure 3.
Electrical strike statistic obtained from multi-sites and multi-frequencies imaging technique
图 4
不同频率范围的最佳主轴统计成像结果
Figure 4.
The geo-electric strikes statistic obtained from different frequency band and shown in both rose histogram (the uppers) and site-based cloud diagram (the lowers)
图 5
CCZ自由分解后得到的一维偏离度(左)、二维偏离度(中)、二维有效因子(右)
Figure 5.
The 1-D skew (left), 2D skew (middle) and 2D effective factor (right) obtained from CCZ method
图 6
沿剖面的Parkinson感应矢量分布图(上)及典型测点的倾子矢量幅度曲线(下)
Figure 6.
Parkinson induction vectors along MT profile (the uppers) and amplitude curves of Tipper data in typical sites (the lowers)
图 7
共主轴多测点多频点阻抗张量分解后的视电阻率和相位拟断面图
Figure 7.
Pseudo section of apparent resistivity (the uppers) and impedance phase (the lowers) after impedance tensor decomposition using a fixed strike
图 8
带地形的二维反演网格及质量评价参数
Figure 8.
The 2D inversion grid with topography and its corresponding evaluation parameters
图 9
TE(左)、TM(中)、TE+TM(右)极化模式的反演结果
Figure 9.
Inversion results using TE mode (left), TM mode (middle) and TE+TM mode (right)
图 10
(a) 关于正则化因子的Фd-Фm曲线交绘图(L曲线图)，曲线上的参数为反演正则化因子tau；(b)关于印模深度的Фd-Фm曲线交绘图，曲线上的参数为印模深度(单位km)；(c)、(d)、(e)分别是印模深度为65 km、50 km、25 km的反演结果，图件上方的标注见图 9所注，(c′)、(d′)、(e′)为对应的初始模型.
Figure 10.
(a) The L curve analysis, which is based on data object function (Фd) and model object function (Фm), is for selecting an optical regularization factor (tau). The numbers shown in the curve stand for the regularization factors used in inversions. (b) Фd-Фm cross graph, which is based on data object function (Фd) and model object function (Фm), is for selecting an optical impressed depth for constructing starting model. The numbers shown in the curve stand for the impressed depths (km) used in inversions. (c), (d), (e) represent the inversion results using the impressed depths of 65 km, 50 km, 25 km, respectively. Their corresponding starting model were shown in (c′), (d′), (e′), respectively.
图 11
观测数据与反演模型响应拟断面图
Figure 11.
Pseudo section of observed data (the uppers) and response (the lowers)
图 12
反演结果模型关键构造的正演验证
Figure 12.
Forward modelling test of critical electrical structures
图 13
反演模型的趋肤深度等值线图.等值线上的参数为频率的对数，背景图为反演结果模型
Figure 13.
Superimposed inversion model with contour map of skin depth and the label in contour map represents the logarithm of frequency. The back is the final model of inversion results
-
An X W, Chang Z F, Shi J F. 2009. Investigation of late quaternary activity along the south-western segment of the Dayingjiang fault. Journal of Seismological Research (in Chinese), 32(2):193-197. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzyj200902015
Bai D H, Meju M A, Liao Z J. 2001. Magnetotelluric images of deep crustal structure of the Rehai geothermal field near Tengchong, southern China. Geophysical Journal International, 147(3):677-687. doi: 10.1046/j.0956-540x.2001.01568.x
Bai D H, Meju M A. 2003. Deep structure of the Longling-Ruili fault underneath Ruili Basin near the eastern Himalayan Syntaxis:insights from Magnetotelluric imaging. Tectonophysics, 364(3-4):135-146. doi: 10.1016/S0040-1951(03)00054-4
Cai J T, Chen X B. 2010. Refined techniques for data processing and two-dimensional inversion in magnetotelluric Ⅱ:which data polarization mode should be used in 2D inversion. Chinese Journal of Geophysics (in Chinese), 53(11):2703-2714, doi:10.3969/j.issn.0001-5733.2010.11.018.
Cai J T, Chen X B, Zhao G Z. 2010. Refined techniques for data processing and two-dimensional inversion in magnetotelluric Ⅰ:tensor decomposition and dimensionality analysis. Chinese Journal of Geophysics (in Chinese), 53(10):2516-2526, doi:10.3969/j.issn.0001-5733.2010.10.025.
Cao L M, Xu Y, Wu S G. 2013. Finite difference tomography of the crustal velocity structure in Tengchong, Yunnan province. Chinese Journal of Geophysics (in Chinese), 56(4):1159-1167, doi:10.6038/cjg20130411.
Chang Z F, Chen G, Yu J Q. 2011. Geological evidence of activity along the Dayingjiang fault since late Pleistocene. Seismology and Geology (in Chinese), 33(4):877-888, doi:10.3969/j.issn.0253-4967.2011.04.012.
Chen L D, Zhao W C. 1979. The 1976 Longling Earthquakes (in Chinese). Beijing:Seismological Press.
Chen X B, Cai J T, Wang L F, et al. 2014. Refined techniques for magnetotelluric data processing and two-dimensional inversion (Ⅳ):statistical image method based on multi-site, multi-frequency tensor decomposition. Chinese Journal of Geophysics (in Chinese), 57(6):1946-1957, doi:10.6038/cjg20140625.
Chen X B, Guo C L. 2017. Refined techniques for magnetotelluric data processing and two-dimensional inversion (Ⅴ):Detecting the linear structures of the earth by impedance tensor. Chinese Journal of Geophysics (in Chinese), 60(2):766-777, doi:10.6038/cjg20170227.
Chen X B, Zhao G Z, Tang J, et al. 2005. An adaptive regularized inversion algorithm for magnetotelluric data.Chinese Journal of Geophysics (in Chinese), 48(4):937-946. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqwlxb200504029
Chen X B, Zhao G Z. 2009. Automatic construction of a Site-Centered Grid (SCG) for 2D magnetotelluric inversion. Chinese Journal of Geophysics (in Chinese), 52(6):1564-1572, doi:10.3969/j.issn.0001-5733.2009.06.018.
Chen X B, Zhao G Z, Zhan Y. 2004. Windows visual integrated system of MT data processing and interpreting. Oil Geophysical Prospecting (in Chinese), 39 (S1):11-16.
Chen X B, Zhao G Z, Zhan Y. 2007. A preliminary study on the effective detecting depth of magnetotelluric sounding under complex model (in Chinese). Chinese Geophysical Society. Collection of the 23rd Annual Meeting of the Chinese Geophysical Society.
China Earthquake Administration. 2005. History Strong Earthquake of China (2300 B.C-1911A.D) (in Chinese). Beijing:Seismological Press.
Egbert G D. 1997. Robust multiple-station magnetotelluric data processing. Geophysical Journal International, 130(2):475-496. doi: 10.1111/gji.1997.130.issue-2
Fang L H, Wu J P, Zhang T Z, et al. 2011. Relocation of mainshock and aftershocks of the 2011 Yingjiang MS5.8 earthquake in Yunnan. Acta Seismologica Sinica (in Chinese), 33(2):262-267.
Gamble T D, Goubau W M, Clarke J. 1979. Magnetotellurics with a remote magnetic reference. Geophysics, 44(1):53-68. doi: 10.1190/1.1440923
Guo C L, Chen X B. 2017. Refined processing and two-dimensional inversion of Magnetotelluric (MT) data (Ⅵ):Two-dimensional magnetotelluric inversion based on the staggered model. Chinese Journal of Geophysics (in Chinese), 60(6):2548-2559, doi:10.6038/cjg2018K0244.
Hansen P C. 1992. Analysis of discrete ill-posed problems by means of the L-curve. SIAM Review, 34(4):561-580. doi: 10.1137/1034115
Huang X M, Du Y, Shu S B, et al. 2010. Study of the late Quaternary slip rate along the northern segment on the south branch of Longling-Ruili fault. Seismology and Geology (in Chinese), 32(2):222-232.
Huangfu G, Chen Y, Qin J Z, et al. 2010. The Seismicity in Yunnan (in Chinese). Kunming:Yunnan Science and Technology Press.
Rodi W, Mackie R L. 2001. Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion. Geophysics, 66(1):174-187. doi: 10.1190/1.1444893
Sun J, Xu C F, Jiang Z, et al. 1989. The electrical structure of the crust and upper mantle in the west part of Yunnan province and its relation to crustal tectonics. Seismology and Geology (in Chinese), 11(1):35-45.
Sun Y. 2014. Seismic observation and analysis in Southwestern Yunnan[Ph.D.thesis] (in Chinese). Beijing: Chinese Academy of Geological Sciences.
Wang J Y, Huang S P. 1990. Heat flow in Chinese continent (2th). Seismology and Geology (in Chinese), 12(4):351-366.
Xu X W, Han Z J, Yang X P, et al. 2016. Seismotectonic Map of China and Adjacent Areas. Beijing:Seismological Press.
Xu Y, Li D N, Gao Y, et al. 2015. Relocations of five Yingjiang sequences (China-Myanmar Border):details of seismogenic faults. Bulletin of the Seismological Society of America, 105(1):314-329. doi: 10.1785/0120130326
Yang T, Wu J P, Fang L H, et al. 2011. Relocation of main shock and aftershocks of the 2014 Yingjiang MS5.6 and MS6.1 earthquakes in Yunnan. Seismology and Geology (in Chinese), 38(4):1047-1057. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzdz201604019
Ye T, Chen X B, Yan L J. 2013. Refined techniques for data processing and two-dimensional inversion in magnetotelluric (Ⅲ):using the Impressing Method to construct starting model of 2D magnetotelluric inversion. Chinese Journal of Geophysics (in Chinese), 56(10):3596-3606, doi:10.6038/cjg20131034.
Zhao G Z, Tang J, Zhan Y, et al. 2004. The relationship between crustal electrical structure and block deformation in the northeastern margin of Qinghai-Tibet plateau. Science China Series D:Earth Science (in Chinese), 34(10):908-918.
Zhao X Y, Han L B, Su Y J, et al. 2013. Relocation of MS5.8 event of the 2011 Yingjiang earthquake sequence. Earthquake Research in China (in Chinese), 29(4):438-447. http://d.old.wanfangdata.com.cn/Periodical/dzyj201804003
Zhong D L. 1998. West of the Yunnan-Sichuan Paleotethysides (in Chinese). Beijing:Science Press.
安晓文, 常祖峰, 石静芳. 2009.大盈江断裂西南段晚第四纪活动研究.地震研究, 32(2):193-197. doi: 10.3969/j.issn.1000-0666.2009.02.015
蔡军涛, 陈小斌. 2010.大地电磁资料精细处理和二维反演解释技术研究(二)——反演数据极化模式选择.地球物理学报, 53(11):2703-2714, doi:10.3969/j.issn.0001-5733.2010.11.018. http://www.geophy.cn/CN/abstract/abstract3423.shtml
蔡军涛, 陈小斌, 赵国泽. 2010.大地电磁资料精细处理和二维反演解释技术研究(一)——阻抗张量分解与构造维性分析.地球物理学报, 53(10):2516-2526, doi:10.3969/j.issn.0001-5733.2010.10.025. http://www.geophy.cn/CN/abstract/abstract3351.shtml
陈立德, 赵维城. 1979.一九七六年龙陵地震.北京:地震出版社.
常祖峰, 陈刚, 余建强. 2011.大盈江断裂晚更新世以来活动的地质证据.地震地质, 33(4):877-888, doi:10.3969/j.issn.0253-4967.2011.04.012.
陈小斌, 蔡军涛, 王立凤等. 2014.大地电磁资料精细处理和二维反演解释技术研究(四)——阻抗张量分解的多测点-多频点统计成像分析.地球物理学报, 57(6):1946-1957, doi:10.6038/cjg20140625. http://www.geophy.cn/CN/abstract/abstract10370.shtml
陈小斌, 郭春玲.2017.大地电磁资料精细处理和二维反演解释技术研究(五)——利用阻抗张量成像识别大地线性构造.地球物理学报, 60(2):766-777. http://www.geophy.cn/CN/abstract/abstract13468.shtml
陈小斌, 赵国泽. 2009.自动构建大地电磁二维反演的测点中心网格.地球物理学报, 52(6):1564-1572, doi:10.3969/j.issn.0001-5733.2009.06.018. http://www.geophy.cn/CN/abstract/abstract1067.shtml
陈小斌, 赵国泽, 汤吉等.2005.大地电磁自适应正则化反演算法.地球物理学报, 48(4):937-946. doi: 10.3321/j.issn:0001-5733.2005.04.029 http://www.geophy.cn/CN/abstract/abstract763.shtml
陈小斌, 赵国泽, 詹艳. 2004. MT资料处理与解释的Windows可视化集成系统.石油地球物理勘探, 39(增刊):11-16. http://www.cnki.com.cn/Article/CJFDTotal-SYDQ2004S1004.htm
陈小斌, 赵国泽, 詹艳. 2007.复杂模型下大地电磁有效探测深度的研究初步.中国地球物理学会.中国地球物理学会第二十三届年会论文集.
房立华, 吴建平, 张天中等. 2011.2011年云南盈江MS5.8地震及其余震序列重定位.地震学报, 33(2):262-267. http://d.old.wanfangdata.com.cn/Periodical/dizhen201102013
郭春玲, 陈小斌. 2018.大地电磁资料精细处理和二维反演解释技术研究(六)——交错模型的大地电磁二维反演.地球物理学报, 60(6):2548-2559, doi:10.6038/cjg2018K0244. http://www.geophy.cn/CN/abstract/abstract14565.shtml
皇甫岗, 陈颐, 秦嘉政等. 2010.云南地震活动性.昆明:云南科技出版社.
黄学猛, 杜义, 舒赛兵等. 2010.龙陵-瑞丽断裂(南支)北段晚第四纪活动性特征.地震地质, 32(2):222-232. doi: 10.3969/j.issn.0253-4967.2010.02.005
孙洁, 徐常芳, 江钊等. 1989.滇西地区地壳上地幔电性结构与地壳构造活动的关系.地震地质, 11(1):35-45. http://www.cnki.com.cn/Article/CJFDTOTAL-DZDZ198901004.htm
孙尧. 2014.滇西南地震观测与分析研究[博士论文].北京: 中国地质科学院.
汪集旸, 黄少鹏. 1990.中国大陆地区大地热流数据汇编(第二版).地震地质, 12(4):351-366. http://d.old.wanfangdata.com.cn/Periodical/dqwlxb200105005
闻学泽, 易桂喜. 2003.川滇地区地震活动统计单元的新划分.地震研究, S1:1-9. http://d.old.wanfangdata.com.cn/Periodical/dzyj2003z1002
徐锡伟, 韩竹军, 杨晓平等. 2016.中国及邻区地震构造图.北京:地震出版社.
杨婷, 吴建平, 房立华等. 2016.云南盈江MS5.6和MS6.1地震余震序列重定位.地震地质, 38(4):1047-1057. http://d.old.wanfangdata.com.cn/Periodical/dizhen201102013
叶涛, 陈小斌, 严良俊. 2013.大地电磁资料精细处理和二维反演解释技术研究(三)——构建二维反演初始模型的印模法.地球物理学报, 56(10):3596-3606, doi:10.6038/cjg20131034. http://www.geophy.cn/CN/abstract/abstract9792.shtml
赵国泽, 汤吉, 詹艳等. 2004.青藏高原东北缘地壳电性结构和地块变形关系的研究.中国科学D辑:地球科学, 34(10):908-918. http://d.old.wanfangdata.com.cn/Periodical/zgkx-cd200410003
赵小艳, 韩立波, 苏有锦等. 2013.2011年云南盈江MS5.8地震序列重定位.中国地震, 29(4):438-447. http://d.old.wanfangdata.com.cn/Periodical/dizhen201102013
钟大赉. 1998.滇川西部古特提斯造山带.北京:科学出版社.
中国地震局监测预报司. 2005.中国强地震目录(公元前23世纪-公元2005年6月).北京:地震出版社.
-
下载:
图(14)
计量
- 文章访问数: 1542
- PDF下载数: 579
- 施引文献: 0