THREE-DIMENSIONAL CRUST STRUCTURE BENEATH SE TIBETAN PLATEAU AND ITS SEISMOTECTONIC IMPLICATIONS FOR THE LUDIAN AND JINGGU EARTHQUAKES

doi:10.3969/j.issn.0253-4967.2014.04.021

Abstract

Abstract:

A detailed 3D crust S-wave velocity model is derived from joint analysis of Rayleigh wave group velocity and teleseismic P-wave receiver functions at permanent stations on the southeast margin of Tibet plateau and its surrounding area. Our new models show the velocity structure in the crust beneath SE Tibet is strongly heterogeneous. There are strong lateral variations in crustal thickness, which increases gradually from 30km in the south and east of Yunan to～65km in the SE Tibetan Plateau. Two obvious low velocity zones (LVZs) are revealed at various depths in the crust. The shallower LVZ in the middle crust (15～20km depth) are limited in the Tengchong volcano and Sichuan-Yunnan (Chuan-Dian) rhombus block. Another LVZ in the middle-to-lower crust varies between 25 and 40km and it shallows toward the east and southeast and is absent in the Sichuan Basin and the southern part of this study area. Our shear velocity model clearly shows an upper crustal high-velocity body and two LVZs in the middle crust and middle-to-lower crust (30～40km depth) across the source area of the 2014 Ludian earthquake. Ludian earthquake sequences and the neighbouring Yongshan-Daguan seismic zone are distributed in the upper crustal high-velocity body. In contrast, no obvious intra-crustal low velocity zones (IC-LVZs) appear beneath the Jinggu earthquake and its adjacent areas. But low velocity anomalies are found in the upper crust beneath the Jinggu earthquake and its neighbouring Simao-Pu'er seismic zone, which may be due to a highly fractured and fluid-filled rock matrix that may have initiated the nucleation of the Jinggu earthquake.

Key words: southeast edge of Tibet plateau, crust structure, joint inversion, receiver function, Rayleigh wave dispersion

摘要：

通过联合解释青藏高原东南缘地区Rayleigh波群速度频散和固定地震台站的远震接收函数, 构建了青藏东南缘3维地壳剪切波速度模型.结果表明研究区地壳结构具有强烈的横向不均一性.该区地壳厚度变化强烈(30～65km), 其总体趋势是东南浅、西北深.研究显示该区存在2个明显的壳内低速异常带, 其中中地壳(15～20km)低速带主要分布在腾冲、川滇菱形块体内部;而25～40km深度范围的中、下地壳低速带主要出现在研究区的北部, 而在四川盆地和研究区南部则普遍缺失.鲁甸地震所在地震带的上地壳表现为高速异常, 中、下地壳范围内存在2个显著的壳内低速带.鲁甸地震主震及其多数余震分布在高速的上地壳之中.与之不同, 景谷地震序列及其所在思茅-普洱地震带下方没有显著的壳内低速带的出现, 但其上地壳则表现为S波低速异常, 该上地壳低速异常可能与地壳强烈破碎及断层/微裂隙中的流体有关.

关键词: 青藏高原东南缘, 地壳结构, 联合反演, 接收函数, Rayleigh波频散

CLC Number:

P315.63

LI Yong-hua, XU Xiao-ming, ZHANG En-hui, GAO Jia-yi. THREE-DIMENSIONAL CRUST STRUCTURE BENEATH SE TIBETAN PLATEAU AND ITS SEISMOTECTONIC IMPLICATIONS FOR THE LUDIAN AND JINGGU EARTHQUAKES[J]. SEISMOLOGY AND GEOLOGY, 2014, 36(4): 1204-1216.

李永华, 徐小明, 张恩会, 高家乙. 青藏高原东南缘地壳结构及云南鲁甸、景谷地震深部孕震环境[J]. 地震地质, 2014, 36(4): 1204-1216.

References

邓起东, 张培震, 冉勇康, 等. 2002. 中国活动构造基本特征［J］. 中国科学(D辑), 32(12):1020—1030.
DENG Qi-dong, ZHANG Pei-zhen, RAN Yong-kang, et al. 2002. Basics characteristics of active tectonics of China ［J］. Science in China (Ser D), 32(12):1020—1030(in Chinese).
蔡麟孙, 李兴林. 2002. 云南省地质［A］. 见: 马丽芳主编. 中国地质图集. 北京: 地质出版社.
CAI Lin-sun, LI Xing-lin. 2002. Geology of Yunnan Province ［A］. In: Ma Li-fang(ed). Geological Atlas of China. Geological Publishing House, Beijing(in Chinese).
陈九辉, 刘启元, 李顺成, 等. 2005. 青藏高原东北缘-鄂尔多斯地块地壳上地幔S波速度结构［J］. 地球物理学报, 48(2): 333—342.
CHEN Jiu-hui, LIU Qi-yuan, LI Shun-cheng, et al. 2005. Crust and upper mantle S wave velocity structure across northeastern Tibetan Plateau and Ordos block ［J］. Chinese Journal of Geophysics, 48(2): 333—342(in Chinese).
房立华, 吴建平, 王未来, 等. 2014. 云南鲁甸M_S6.5地震余震重定位及其发震构造［J］. 地震地质, 36(4): 1173—1185. doi: 10.3969/j.issn.0253-4967.2014.04.021
FANG Li-hua, WU Jian-ping, WANG Wei-lai, et al. 2014. Relocation of the aftershock sequence of the M_S6.5 Ludian earthquake and its seismogenic structure ［J］. Seismology and Geology, 36(4): 1173—1185(in Chinese).
胡家富, 朱雄关, 夏静瑜, 等. 2005. 利用面波和接收函数联合反演滇西地区壳幔速度结构［J］. 地球物理学报, 48(5): 1069—1076.
HU Jia-fu, ZHU Xiong-guan, XIA Jing-yu, et al. 2005. Using surface wave and receiver function to jointly inverse the crust-mantle velocity structure in the West Yunnan area ［J］. Chinese Journal of Geophysics, 48(5): 1069—1076(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 Journal of Geophysics, 52(1): 67—80(in Chinese).
刘启元, 李昱, 陈九辉, 等. 2010. 基于贝叶斯理论的接收函数与环境噪声联合反演［J］. 地球物理学报, 53(11): 2603—2612.
LIU Qi-yuan, LI Yu, CHEN Jiu-hui, et al. 2010. Joint inversion of receiver function and ambient noise based on Bayesian theory ［J］. Chinese Journal of Geophysics, 53(11): 2603—2612(in Chinese).
刘启元, Rainer Kind, 李顺成. 1996. 接收函数复谱比的最大或然性估计及非线性反演［J］. 地球物理学报, 39(4): 500—511.
LIU Qi-yuan, Rainer Kind, LI Shun-cheng. 1996. Maximal likelihood estimation and nonlinear inversion of the complex receiver function spectrum ratio ［J］. Chinese Journal of Geophysics, 39(4): 500—511(in Chinese).
罗荣联, 陈玉茹. 1996. 云南历史强震活动图像［J］. 地震研究, 19(3): 253—259.
LUO Rong-lian, CHEN Yu-ru. 1996. The patterns of historical strong earthquakes in Yunnan ［J］. Journal of Seismological Research, 19(3): 253—259(in Chinese).
苏有锦, 刘祖荫, 蔡民军, 等. 1999. 云南地区强震分布的深部地球介质背景［J］. 地震学报, 21(3): 313—322.
SU You-jin, LIU Zu-yin, CAI Min-jun, et al. 1999. Deep medium environment of strong earthquakes occurrence in Yunnan region ［J］. Acta Seismologica Sinica, 21(3): 313—322(in Chinese).
王未来, 吴建平, 房立华, 等. 2014. 2014年云南鲁甸M_S6.5地震序列的双差定位［J］. 地球物理学报, 57(9): 3042—3051.
WANG Wei-lai, WU Jian-ping, FANG Li-hua, et al. 2014. Double difference location of the Ludian M_S6.5 earthquake sequences in Yunnan Province in 2014 ［J］. Chinese Journal of Geophysics, 57(9): 3042—3051(in Chinese).
闻学泽, 杜方, 易桂喜, 等. 2013. 川滇交界东段昭通、莲峰断裂带的地震危险背景［J］. 地球物理学报, 56(10): 3361—3372.
WEN Xue-ze, DU Fang, YI Gui-xi, et al. 2013. Earthquake potential of the Zhaotong and Lianfeng Fault zones of the eastern Sichuan-Yunnan border region ［J］. Chinese Journal of Geophysics, 56(10): 3361—3372(in Chinese).
吴建平, 明跃红, 王椿镛. 2004. 云南地区中小地震震源机制及构造应力场研究［J］. 地震学报, 26(5): 457—465.
WU Jian-ping, MING Yue-hong, WANG Chun-yong. 2004. Source mechanism of small-moderate earthquakes and tectonic stress field in Yunnan Province ［J］. Acta Seismologica Sinica, 26(5): 509—517(in Chinese).
吴建平, 杨婷, 王未来, 等. 2013. 小江断裂带周边地区三维P波速度结构及其构造意义［J］. 地球物理学报, 56(7): 2257—2267.
WU Jian-ping, YANG Ting, WANG Wei-lai, et al. 2013. Three dimensional P-wave velocity structure around Xiaojiang Fault system and its tectonic implications ［J］. Chinese Journal of Geophysics, 56(7): 2257—2267(in Chinese).
吴庆举, 田小波, 张乃铃, 等. 2003. 计算台站接收函数的最大熵谱反褶积方法［J］. 地震学报, 25(4): 382—389.
WU Qing-ju, TIAN Xiao-bo, ZHANG Nai-ling, et al. 2003. Receiver function estimated by maximum entropy deconvolution ［J］. Acta Seismologica Sinica, 25(4): 382—389(in Chinese).
吴庆举, 曾融生. 1998. 用宽频带远震接收函数研究青藏高原的地壳结构［J］. 地球物理学报, 41(5): 669—679.
WU Qing-ju, ZENG Rong-sheng. 1998. The crustal structure of Qinghai-Xizang plateau inferred from broadband teleseismic waveform ［J］. Chinese J Geophys, 41(5): 669—679(in Chinese).
徐涛, 张明辉, 田小波, 等. 2014. 丽江—清镇剖面上地壳速度结构及其与鲁甸M_S6.5地震孕震环境的关系［J］. 地球物理学报, 57(9): 3069—3079.
XU Tao, ZHANG Ming-hui, TIAN Xiao-bo, et al. 2014. Upper crustal velocity of Lijiang-Qingzhen profile and its relationship with the seismogenic environment of the M_S6.5 Ludian earthquake ［J］. Chinese Journal of Geophysics, 57(9): 3069—3079(in Chinese).
徐锡伟, 江国焰, 于贵华, 等. 2014. 鲁甸6.5级地震发震断层判定及其构造属性讨论［J］. 地球物理学报, 57(9): 3060—3068.
XU Xi-wei, JIANG Guo-yan, YU Gui-hua, et al. 2014. Discussion on seismogenic fault of the Ludian M_S6.5 earthquake and its tectonic attribution ［J］. Chinese Journal of Geophysics, 57(9): 3060—3068(in Chinese).
张晓曼, 胡家富, 胡毅力, 等. 2011. 云南壳幔S波速度结构与强震的构造背景［J］. 地球物理学报, 54(5): 1222—1232.
ZHANG Xiao-man, HU Jia-fu, HU Yi-li, et al. 2011. The S-wave velocity structure in the crust and upper mantle as well as the tectonic setting of strong earthquake beneath Yunnan region ［J］. Chinese Journal of Geophysics, 54(5): 1222—1232(in Chinese).
Ammon C J, Randall G E, Zandt G. 1990. On the non-uniqueness of receiver function inversions ［J］. J Geophys Res, 95(B10): 15303—15318.
Bai D H, Unsworth M J, Meju M A, et al. 2010. Crustal deformation of the eastern Tibetan Plateau revealed by magnetotelluric imaging ［J］. Nature Geoscience, 3: 358—362.
Chen Chau-huei, Wang Wei-hau, Teng Ta-liang. 2001. 3D velocity structure around the source area of the 1999 Chi-Chi, Taiwan, earthquake: Before and after the mainshock ［J］. Bulletin of the Seismological Society of America, 91(5): 1013—1027.
Chen Y, Badal J, Hu J F. 2010. Love and Rayleigh wave tomography of the Qinghai-Tibet plateau and surrounding areas ［J］. Pure Appl Geophys, 167: 1171—1203.
Ditmar P G, Yanovskaya T B. 1987. A generalization of the Backus-Gilbert method for estimation of lateral variations of surface wave velocity ［J］. Izv Phys Solid Earth, 23: 470—477.
Herrmann R B, Ammon C J. 2004. Computer Programs in Seismology ［Z］. St Louis, MO. http: //www.eas.slu.edu eqceqccps.html.
Huang J, Liu X J, Su Y J, et al. 2012. Imaging 3-D crustal P-wave velocity structure of western Yunnan with bulletin data ［J］. Earthq Sci, 25: 151—160.
Huang J, Zhao D, Zheng S. 2002. Lithospheric structure and its relationship to seismic and volcanic activity in southwest China ［J］. Journal of Geophysical Research, 107(B10): 2255.
Julià J, Ammon C J, Herrmann R B, et al. 2000. Joint inversion of receiver function and surface wave dispersion observations ［J］. Geophys J Int, 143: 99—112.
Kennett B L N, Engdahl E R, Buland R. 1995. Constraints on seismic velocities in the Earth from traveltimes ［J］. Geophys J Int, 122: 108—124.
Laske G, Masters G, Ma Z, et al. 2012. CRUST1.0: An updated global model of the Earth's crust ［A］. EGU General Assembly, 14, p. 3743.
Li Y H, Wu Q J, Pan J T, et al. 2013. An upper-mantle S-wave velocity model for East Asia from Rayleigh wave tomography ［J］. Earth and Planetary Science Letters, 377—378: 367—377.
Li Y H, Wu Q J, Zhang R Q, et al. 2008. The crust and upper mantle structure beneath Yunnan from joint inversion of receiver functions and Rayleigh wave dispersion data ［J］. Physics of the Earth and Planetary Interiors, 170: 134—146.
Li Y H, Gao M T, Wu Q J. 2014a. Crustal thickness map of the Chinese mainland from teleseismic receiver functions ［J］. Tectonophysics, 611(25): 51—60.
Li Y H, Pan J T, Wu Q J, et al. 2014b. Crustal and uppermost mantle structure of SE Tibetan Plateau from Rayleigh-wave group-velocity measurements ［J］. Earthquake Science, 27(4): 411—419.
Liu Q Y, van der Hilst R D, Li Y, et al. 2014. Eastward expansion of the Tibetan Plateau by crustal flow and strain partitioning across faults ［J］. Nature Geoscience, 7: 361—365.
Sun X X, Bao X W, Xu M J, et al. 2014. Crustal structure beneath SE Tibet from joint analysis of receiver functions and Rayleigh wave dispersion ［J］. Geophysical Research Letters, 41(5): 1479—1484.
Tian X, Wu Q, Zhang Z, et al. 2005. Joint imaging by teleseismic converted and multiple waves and its application in the INDEPTH-Ⅲ passive seismic array ［J］. Geophysical Research Letters, 32: L21315.
Wang Z, Zhao D, Wang J. 2010. Deep structure and seismogenesis of the north-south seismic zone in southwest China ［J］. Journal of Geophysical Research, 115(12): B12334.
Xu X M, Ding Z F, Shi D N, et al. 2013. Receiver function analysis of crustal structure beneath the eastern Tibetan Plateau ［J］. J Asian Earth Sci, 73: 121—127.
Yang Y, 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, 117: B04303.
Yanovskaya T B, Ditmar P G. 1990. Smoothness criteria in surface wave tomography ［J］. Geophys J Int, 12: 63—72.
Zhao D, Kanamori H, Negish H i, et al. 1996. Tomography of the source area of the 1995 Kobe earthquake: Evidence for fluids at the hypocenter ［J］. Science, 274: 1891—1894.
Zhao D, Ochi F, Hasegawa A, et al. 2000. Evidence for the location and cause of large crustal earthquakes in Japan ［J］. J Geophys Res, 105(B6): 13579—13594.

[1]	YANG Jian-wen, JIN Ming-pei, CHA Wen-jian, ZHANG Tian-ji, YE Beng. CRUSTAL S-WAVE VELOCITY STRUCTURE BENEATH THE XIAO-JIANG FAULT ZONE AND ADJACENT REGIONS REVEALED BY TWO-STEP INVERSION METHOD OF RECEIVER FUNCTIONS [J]. SEISMOLOGY AND GEOLOGY, 2023, 45(1): 190-207.
[2]	SONG Ting, SHEN Xu-zhang, MEI Xiu-ping, JIAO Yu-yuan, LI Min-juan, SU Xiao-yun, JI Wan-jing. CONSTRAINING MOHO CHARACTERISTICS IN THE NORTH-EASTERN MARGIN OF TIBET PLATEAU WITH FREQUENCY-DEPENDENCE OF RECEIVER FUNCTION [J]. SEISMOLOGY AND GEOLOGY, 2022, 44(5): 1290-1312.
[3]	PAN Ji-shun, LI Peng-hui, DUAN Yong-hong, ZHAO Yan-na, PENG Yi-cong, SUN Kai-xuan. STUDY ON THE CRUSTAL STRUCTURE OF THE CENTRAL AND WESTERN PART OF THE NORTH CHINA CRATON [J]. SEISMOLOGY AND EGOLOGY, 2021, 43(5): 1269-1291.
[4]	WANG Ji-xin, RONG Mian-shui, FU Li-yun, FU Lei. JOINT INVERSION OF SITE VELOCITY STRUCTURE BY MICRO-TREMOR ARRAY RECORD: A CASE STUDY OF THE OBSER-VATION SITE 3^# OF XIANGTANG IN TANGSHAN [J]. SEISMOLOGY AND GEOLOGY, 2020, 42(6): 1335-1353.
[5]	KONG Xiang-yan, WU Jian-ping, FANG Li-hua, CAI Yan, FAN Li-ping, WANG Wei-lai. JOINT INVERSION OF SURFACE WAVE DISPERSION AND RECEIVER FUNCTIONS FOR CRUSTAL AND UPPERMOST MANTLE STRUCTURE BENEATH CHINESE TIENSHAN AND ITS ADJACENT AREAS [J]. SEISMOLOGY AND GEOLOGY, 2020, 42(4): 844-865.
[6]	GAO Jian, YANG Yi-hai, HUANG Shi-yuan, YANG Cong, ZHANG Yuan-sheng, LIU Cun-xi, LI Shao-rui, HUA Qian. CRUSTAL ANISOTROPY AND ITS TECTONIC IMPLICATIONS IN THE CHONGQING REGION [J]. SEISMOLOGY AND GEOLOGY, 2020, 42(1): 147-162.
[7]	TANG Ming-shuai, WANG Hai-tao, WEI Yun-yun, LI Yan-yong, GE Can, WANG Qiong, SU Jin-bo, WEI Bin. POISSON'S RATIO VARIATIONS OF CRUSTAL MEDIA BEFORE AND AFTER XINYUAN-HEJING M_S6.6 EARTHQUAKE IN 2012 [J]. SEISMOLOGY AND GEOLOGY, 2019, 41(5): 1123-1135.
[8]	LI Xi-bing, XIONG Zhen, FAN Xiao-ping, TAO Xiao-san, PENG Xiao-bo. THE 3-D VELOCITY STRUCTURE OF CRUST AND UPPERMOST MANTLE AND ITS TECTONIC IMPLICATIONS IN FUJIAN PROVINCE [J]. SEISMOLOGY AND GEOLOGY, 2019, 41(5): 1206-1222.
[9]	ZHANG Zhi-wei, LONG Feng, WANG Shi-yuan, GONG Yue, WU Peng, WANG Hui, JIANG Guo-mao. EARTHQUAKE LOCATION AND VELOCITY STRUCTURE IN YIBIN AREA, SICHUAN [J]. SEISMOLOGY AND GEOLOGY, 2019, 41(4): 913-926.
[10]	LIU Yun-hua, SHAN Xin-jian, ZHANG Ying-feng, ZHAO De-zheng, QU Chun-yan. USE OF SEISMIC WAVEFORMS AND INSAR DATA FOR DETERMINATION OF THE SEISMOTECTONICS OF THE MAINLING M_S6.9 EARTHQUAKE ON NOV.18, 2017 [J]. SEISMOLOGY AND GEOLOGY, 2018, 40(6): 1254-1275.
[11]	WENG Ai-hua, LI Jian-ping, FAN Xiao-ping, LI Si-rui, HAN Jiang-tao, LI Da-jun, LI Ya-bin, ZHAO Xiang-yang, TANG Yu. FINE ELECTRICAL STRUCTURE BENEATH THE EPICENTER OF 1668 TANCHENG M_S8.5 EARTHQUAKE REVEALED BY MT SOUNDING [J]. SEISMOLOGY AND GEOLOGY, 2018, 40(2): 396-409.
[12]	LUO Jia-hong, MA Wen-tao. A PRELIMINARY STUDY ON UPPER CRUSTAL VELOCITY STRUCTURE IN THE THREE GORGES RESERVOIR AREA [J]. SEISMOLOGY AND GEOLOGY, 2016, 38(2): 329-341.
[13]	WANG Lin, ZHOU Qing-yun, WANG Jun, LI Wen-qiao, ZHOU Lian-qing, CHEN Han-lin, SU Peng, LIANG Peng. THE RESEARCH OF THE SEISMOGENIC STRUCTURE OF THE LUSHAN EARTHQUAKE BASED ON THE SYNTHESIS OF THE DEEP SEISMIC DATA AND THE SURFACE TECTONIC DEFORMATION [J]. SEISMOLOGY AND GEOLOGY, 2016, 38(2): 458-476.
[14]	WANG Xin, ZHANG Jing-fa, FU Ping-jie, GAO Min. DEEP STRUCTURES OF YISHU FAULT ZONE DERIVED FROM GRAVITY DATA [J]. SEISMOLOGY AND GEOLOGY, 2015, 37(3): 731-747.
[15]	HONG De-quan, WANG Xing-zhou, LI Jun-hui, NI Si-dao. STUDY ON THE CRUSTAL THICKNESS BENEATH STATIONS OF SEISMIC NETWORK IN ANHUI PROVINCE BY TELESEISMIC RECEIVER FUNCTION [J]. SEISMOLOGY AND GEOLOGY, 2013, 35(4): 853-863.