CRUSTAL STRUCTURE FROM YUNXIAN-NINGLANG WIDE-ANGLE SEISMIC REFLECTION AND REFRACTION PROFILE IN NORTHWESTERN YUNNAN, CHINA

doi:10.3969/j.issn.0253-4967.2016.01.007

Abstract

Abstract:

The Red River Fault in western Yunnan is one of the longest strike-slip faults in China and has a high seismic potential. To investigate its complicated structure, a near-NS directed 300km long wide-angle reflection/refraction seismic profile was laid out from Yunxian to Ninglang, across the Red River Fault. The 2-D velocity structure model along the profile was obtained through 1-D and 2-D analysis and fitting the observed data with combination of first-arrival traveltime tomography and forward modeling. The results indicate:In the crust, the average P-wave velocity is 6.2~6.3km/s and basically shows a positive gradient structure, but there are some low velocity anomalies at different area in upper and lower crust. Regarding the crust boundary, a relative large lateral variation exists in the depth of Moho, which goes deeper from south to north, ranging from 45km to as deep as 54km; compared to other typical continental crust, the study area demonstrates a striking thickening. It should be mentioned that the crustal thickening is mainly observed in the lower crust, while the upper and middle crust possess nearly constant thickness. We observed strong seismic velocity contrast across the Red River Fault, which emphasizes the role of the fault as an important tectonic boundary between Yangtze paraplatform and Sanjiang geosynclinal system. Along the profile, the Moho depth has no remarkable variation when crossing the Red River Fault. Combining with other study results on nearby area, it proves that there is notable heterogeneity between different parts of the Red River Fault.

Key words: western Yunnan, two-dimensional crustal velocity structure, wide-angle reflection/refraction, Red River Fault

摘要：

位于滇西地区的红河断裂是中国最长的走滑断裂之一,具有很高的地震潜势。为了调查红河断裂的复杂结构,在滇西地区穿过红河深大断裂带完成了1条由云县至宁蒗近SN向长300km的宽角地震反射/折射剖面。结合初至波走时成像及正演建模方法,对该测线观测数据进行了一维、二维分析拟合,获得了该地区沿测线的二维地壳速度结构模型。结果显示:地壳P波平均速度为6.2~6.3km/s,基本呈现为1个均匀的正速度梯度结构,但在中地壳和下地壳不同区域有部分低速异常;沿测线Moho界面埋深存在较大的横向变化,自南向北明显变深,南侧Moho埋深约为45km,北侧Moho埋深可达54km,较之典型的大陆地壳,存在明显的增厚现象;而沿测线中上地壳厚度变化不大,地壳增厚主要缘于下地壳厚度的增加;以红河断裂为界,地壳结构存在明显的横向差异,暗示了红河断裂作为扬子准地台和三江地槽系构造边界的作用;测线穿过区域红河断裂两侧没有明显的Moho埋深变化,结合临近区域的其他研究结果,表明红河断裂在不同区段存在较大的差异。

关键词: 二维地壳速度结构, 宽角反射/折射, 红河断裂, 滇西地区

CLC Number:

P313.2

CHEN Si-wen, WANG Bao-shan, TIAN Xiao-feng, WANG Fu-yun, LIU Bao-feng, LI Lu. CRUSTAL STRUCTURE FROM YUNXIAN-NINGLANG WIDE-ANGLE SEISMIC REFLECTION AND REFRACTION PROFILE IN NORTHWESTERN YUNNAN, CHINA[J]. SEISMOLOGY AND GEOLOGY, 2016, 38(1): 91-106.

陈思文, 王宝善, 田晓峰, 王夫运, 刘宝峰, 李璐. 滇西北地区云县-宁蒗宽角反射/折射剖面结果[J]. 地震地质, 2016, 38(1): 91-106.

References

白志明, 王椿镛. 2003. 云南地区上部地壳结构和地震构造环境的层析成像研究［J］. 地震学报, 25(2):117-127.
BAI Zhi-ming, WANG Chun-yong. 2003. Tomographic investigation of the upper crustal structure and seismotectonic environments in Yunnan Province［J］. Acta Seismologica Sinica, 25(2):117-127(in Chinese).
白志明, 王椿镛. 2004. 云南遮放-宾川和孟连-马龙宽角地震剖面的层析成像研究［J］. 地球物理学报, 47(2):257-267.
BAI Zhi-ming, WANG Chun-yong. 2004. Tomograghy research of the Zhefang-Binchuan and Menglian-Malong wide-angle seismic profiles in Yunnan［J］. Chinese J Geophys, 47(2):257-267(in Chinese).
常利军, 王椿镛, 丁志峰. 2006. 云南地区 SKS 波分裂研究［J］. 地球物理学报, 49(1):197-204.
CHANG Li-jun, WANG Chun-yong, DING Zhi-feng. 2006. A study on SKS splitting beneath the Yunnan region［J］. Chinese J Geophys, 49(1):197-204(in Chinese).
邓起东. 2007. 中国活动构造图(1:400万)[CM]. 北京:地震出版社.
DENG Qi-dong. 2007. Active Tectonics Map of China(1:4,000,000)[CM]. Seismological Press, Beijing(in Chinese).
嘉世旭, 刘昌铨. 1995. 华北地区人工地震测深震相与地壳结构研究［J］. 地震地质,17(2):97-105.
JIA Shi-xu, LIU Chang-quan. 1995. Study on the seismic phase of DSS in North China［J］. Seismology and Geology, 17(2):97-105(in Chinese).
阚荣举, 林中洋. 1986. 云南地壳上地幔构造的初步研究［J］. 中国地震, 2(4):50-61.
KAN Rong-ju, LIN Zhong-yang. 1986. A preliminary study on crustal and upper mantle structures in Yunnan［J］. Earthquake Research in China, 2(4):50-61(in Chinese).
李永华, 吴庆举, 田小波, 等. 2009. 用接收函数方法研究云南及其邻区地壳上地幔结构［J］. 地球物理学报, 52(1):67-80.
LI Yong-hua, WU Qing-ju, TIAN Xiao-bo, et al. 2009. Crustal structure in the Yunnan region determined by modeling receiver functions［J］. Chinese J Geophys, 52(1):67-80(in Chinese).
林中洋, 张文彬. 1993. 滇西地区地壳上地幔速度结构特征的研究［J］. 地震学报, 15(4):427-440.
LIN Zhong-yang, ZHANG Wen-bin. 1993. Studies of upper mantle velocity structure in Western Yunnan［J］. Acta Seismologica Sinica, 15(4):427-440(in Chinese).
罗艳, 倪四道, 陈颙. 2010. 超临界距离上SmS震相对强地面振动衰减关系影响的初步探讨［J］. 中国地震, 26(2):131-141.
LUO Yan, NI Si-dao, CHEN Yong. 2010. A case study on the effect of post-critical SmS on ground motion in Yingjiang, Yunnan Province, China［J］. Earthquake Research in China, 26(2):131-141.
谭筱红, 朱志. 1999. 程海断裂新生代活动特征及性质［J］. 云南地质科技情报, (2):21-24.
TAN Xiao-hong, ZHU Zhi. 1999. Characteristics and nature of Cenozoic events on Chenghai Fault, Yunnan［J］. Geological Science and Technology Information, (2):21-24(in Chinese).
王宝善, 王伟涛, 葛洪魁, 等. 2011. 人工震源地下介质变化动态监测［J］. 地球科学进展, (3):249-256.
WANG Bao-shan, WANG Wei-tao, GE Hong-kui, et al. 2011. Monitoring subsurface changes with active sources［J］. Advances in Earth Science, (3):249-256(in Chinese).
王绍晋, 秦嘉政, 李忠华, 等. 2007. 澜沧江断裂带环境剪应力场与地震活动分析［J］. 地震研究, 30(2):127-132.
WANG Shao-jin, QIN Jia-zheng, LI Zhong-hua, et al. 2007. Relationship between seismicity and environmental shear stress field along Lancangjiang fault zone［J］. Journal of Seismological Research, 30(2):127-132(in Chinese).
吴建平, 明跃红, 王椿镛. 2001. 云南数字地震台站下方的 S 波速度结构研究［J］. 地球物理学报, 44(2):228-237.
WU Jing-ping, MING Yue-hong, WANG Chun-yong. 2001. The S-wave velocity structure beneath digital seismic stations of Yunnan Province inferred from teleseismic receiver function modeling［J］. Chinese J Geophys, 44(2):228-237(in Chinese).
向宏发, 韩竹军, 虢顺民, 等. 2004. 红河断裂带大型右旋走滑运动定量研究的若干问题［J］. 地球科学进展, 19(增刊):56-59.
XIANG Hong-fa, HAN Zhu-jun, GUO Shun-min, et al. 2004. Several questions about the quantitative study of the large-scale right-lateral strike-slip movement of the Red River fault zone［J］. Advances in Earth Science, 19(Suppl):56-59(in Chinese).
向宏发, 万景林, 韩竹军, 等. 2006. 红河断裂带大型右旋走滑运动发生时代的地质分析与FT测年［J］. 中国科学(D 辑), 36(11):977-987.
XIANG Hong-fa, WAN jing-lin, HAN Zhu-jun, et al. 2006. Geological analysis and FT dating of the large-scale right-lateral strike-slip movement of the Red River fault zone［J］. Science in China(Ser D), 36(11):977-987(in Chinese).
徐鸣洁, 王良书, 刘建华, 等. 2005. 利用接收函数研究哀牢山-红河断裂带地壳上地幔特征［J］. 中国科学(D辑), 35(8):729-737.
XU Ming-jie, WANG Liang-shu, LIU Jian-hua, et al. 2005. Study on crust and upper mantle structure in Ailaoshan-Honghe faults zone from receiver functions［J］. Science in China(Ser D), 35(8):729-737(in Chinese).
俞维贤, 张建国, 周光全, 等. 2005. 2001年永胜6级地震的地表破裂与程海断裂［J］. 地震研究, (2):125-128.
YU Wei-xian, ZHANG Jian-guo, ZHOU Guang-quan, et al. 2005. Surface rupture of the 2001 Yongsheng M6 earthquake and Chenghai Fault［J］. Journal of Seismological Research, (2):125-128(in Chinese).
张建国. 2009. 中越红河断裂活动性研究[D]:[学位论文]. 合肥:中国科学技术大学.
ZHANG Jian-guo. 2009. Research on the activity of Red River Fault in China and Vietnam[D]. Dissertation. University of Science and Technology of China, Hefei (in Chinese).
张中杰, 白志明, 王椿镛, 等. 2005. 冈瓦纳型和扬子型地块地壳结构:以滇西孟连-马龙宽角反射剖面为例［J］. 中国科学(D 辑), 34(5):387-392.
ZHANG Zhong-jie, BAI Zhi-ming, WANG Chun-yong, et al. 2005. Crustal structure of Gangwana and Yangtze-typed blocks:An example by wide-angle seismic profile from Menglian to Malong in Western Yunnan［J］. Science in China(Ser D), 34(5):387-392(in Chinese).
朱守彪, 石耀林. 2004. 用遗传有限单元法反演川滇下地壳流动对上地壳的拖拽作用［J］. 地球物理学报, 47(2):232-239.
ZHU Shou-biao, SHI Yao-lin. 2004. Genetic algorithm-finite element inversion of drag forces exerted by the lower crust on the upper crust in the Sichuan-Yunnan area［J］. Chinese J Geophys, 47(2):232-239(in Chinese).
Cerveny V. 1979. Ray theoretical seismograms for laterally inhomogeneous structures［J］. J Geophys, 46:335-342.
Cerveny V. 1984. SEIS83-Numerical modeling of seismic wave fields in 2-D laterally varying layered structures by the ray method[M]. In:Engdahl E R (ed). Documentation of Earthquake Algorithms. World Data Center A for Solid Earth Geophysice, Colorado, USA.
Hu Hong-xiang, Lu Han-xing, Wang Chun-yong, et al. 1986. Explosion investigation of the crustal structure in western Yunnan Province［J］. Chinese J Geophys, 29(2):133-144.
Hu Jia-fu, Su You-jin, Zhu Xiong-guan, et al. 2005. S-wave velocity and Poisson's ratio structure of crust in Yunnan and its implication［J］. Science in China(Ser D), 48(2):210-218.
Huang Jing, Liu Xue-jun, Su You-jing, et al. 2012. Imaging 3-D crustal P-wave velocity structure of western Yunnan with bulletin data［J］. Earthquake Science, 25(2):151-160.
Huang Zhou-chuan, Wang Liang-su, Xu Ming-jie, et al. 2007. Shear wave splitting across the Ailao Shan-Red River fault zone, SW China［J］. Geophysical Research Letters, 34(20):L20301.
Kan Rong-ju, Hu Hong-xiang, Zeng Rong-sheng, et al. 1986. Crustal structure of Yunnan Province, People's Republic of China, from seismic refraction profiles［J］. Science, 234:433-437.
Peltzer G, Tapponnier P. 1988. Formation and evolution of strike-slip faults, rifts, and basins during the India-Asia collision:An experimental approach［J］. Journal of Geophysical Research:Solid Earth(1978-2012), 93(B12):15085-15117.
Royden L H, Burchfiel B C, King R W, et al. 1997. Surface deformation and lower crustal flow in eastern Tibet［J］. Science, 276:788-790.
Schärer U, Tapponnier P, Lacassin R, et al. 1990. Intraplate tectonics in Asia:A precise age for large-scale Miocene movement along the Ailao Shan-Red River shear zone, China［J］. Earth and Planetary Science Letters, 97(1):65-77.
Tapponnier P, Lacassin R, Leloup P H, et al. 1990. The Ailao Shan/Red River metamorphic belt:Tertiary left-lateral shear between IndoChina and South China［J］. Nature, 343:431-437.
Yang Y J, Ritzwoller M H, Zheng Y, et al. 2012. A synoptic view of the distribution and connectivity of the mid-crustal low velocity zone beneath Tibet［J］. Journal of Geophysical Research:Solid Earth(1978-2012), 117(B4).
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］. Geophysical Journal International, 166(2):732-744.
Zhang Xi, Wang Yang-hua. 2009. Crustal and upper mantle velocity structure in Yunnan, Southwest China［J］. Tectonophysics, 471(3):171-185.
Zhao Li, Luo Yan, Liu Ting-Yu, et al. 2013. Earthquake focal mechanisms in Yunnan and their inference on the regional stress field［J］. Bulletin of the Seismological Society of America, 103(4):2498-2507.

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