Current state of tectonic stress in northwestern Yunnan and its relationship with earthquakes
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摘要: 基于搜集到的2000—2018年滇西北地区MS≥3.0地震的震源机制解，运用线性叠加反演法进行应力场反演，分析了滇西北地区现今的构造应力状态，进一步探讨了应力张量方差的时空分布与地震活动的关系。结果显示：① 滇西北地区地震的震源机制解类型复杂，主要以走滑型（46%）为主，正断型（27%）次之；② 研究区的构造应力场具有整体的一致性和局部的非均匀性，呈现为NNW向挤压和ENE向拉张的走滑型应力结构，说明研究区受到来自NNW向的水平挤压作用，对该地区上地壳运动和断裂活动起主导作用；③ 滇西北地区的应力张量方差大都小于0.2，除北部一些地区外，应力场基本处于均匀状态。根据应力张量方差随时间的变化和后续地震可知，中强地震大都发生在应力张量方差值低于0.2的情形，且主要发生在应力张量方差减小即震源机制解趋于一致的过程中。空间上这些地震基本都发生在应力张量方差的低值分布区及其边缘，这一结果有助于判定发震地点和了解区域应力集中增强过程。Abstract: Based on collected the focal mechanism solutions of MS≥3.0 earthquakes from 2000 to 2018 in northwestern Yunnan, we analyze the current state of tectonic stress in northwestern Yunnan by Michael’s linear superposition stress inversion method, and further investigate the spatio-temporal distribution of stress tensor variance and its relationship with seismic activity. The results show that the focal mechanism solutions of earthquakes in northwestern Yunnan are complex in types, mainly strike-slip type （46%）, followed by normal-faulting type （27%）. Tectonic stress field is overall consistency and partial inhomogeneity. The tectonic stress field shows strike-slip faulting stress regime with NNSwards principal compressive stress and ENEwards principal tensile stress in the studied area. It suggests that the study area is subjected to horizontal compression from NNW direction, which plays a dominant role in the upper crustal movement and fault activities in this area. Regional grid stress inversion shows that the variance is mostly below 0.2 in northwestern Yunnan, which indicates that the stress field is in a uniform state except for some northern regions. According to the variation of variance with time and subsequent earthquakes, moderate to strong earthquakes in the studied area mostly occurred when the stress tensor variance was lower than 0.2. Most earthquakes mainly occurred during the process that the stress tensor variance decreased, that is, when the focal mechanism solutions tend to be consistent. And spatially these earthquakes basically occur in the low value zones of the variance or near the edge of the zones, which provides reference for judging the earthquake location and comprehending the regional stress concentration enhancement process in the future.
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图 1 本研究所用滇西北地震震源机制解的空间分布图
震源机制解按照Zoback等（1992）分类，震源机制解沙滩球大小随震级增大而增大
Figure 1. The spatial distribution of focal mechanism solutions of the earthquakes in northwestern Yunnan used in this study
The mechanism solutions are classified according to Zoback et al （1992），the size of the beach balls increases with the magnitude of the earthquakes
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图 2 P轴（a）和T轴（b）的方位分布及方位角统计玫瑰图
图中N为地震频次；线段的长短代表倾伏角大小，线段越长，倾伏角越小
Figure 2. The distribution of azimuth and azimuth roses of P axes and T axes
N is the number of earthquakes. The length of the line represents the size of the plunge. The longer the lines，the lower the plunges
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图 3 P轴（a）和T轴（b）的倾伏角统计玫瑰图（图中N为地震频次）
Figure 3. The plunge roses of P axes （a） and T axes （b） where N is the number of earthquakes
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图 4 主应力轴及其95%置信区间（彩色区域）的下半球等面积投影
Figure 4. Lower-hemisphere equal-area projection of principle stress axes and their 95% confidence regions （colorful part）
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图 5 区域分网格反演得到的研究区最大主应力方位分布图
Figure 5. Distribution of maximum principal stress orientation in the studied area by regional grid inversion
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图 6 区域分网格反演得到的研究区应力张量方差分布图
Figure 6. Distribution of stress tensor variance in the studied area obtained by regional grid inversion
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图 7 2000—2018年研究区应力张量方差随时间变化曲线以及MS≥5.0地震分布
Figure 7. Variation of stress tensor variance and MS≥5.0 earthquakes in the studied area in the period of 2000−2018
表 1 线性叠加反演得到的滇西北地区最优应力张量
Table 1 The best-fitting stress tensor of northwestern Yunnan by using linear superposition stress inversion
最大主应力S1 中间主应力S2 最小主应力S3 应力形因子ϕ 应力类型 方位/º 倾伏角/º 方位/º 倾伏角/º 方位/º 倾伏角/º 167.8 7.9 5.8 81.6 258.3 2.5 0.8 走滑型 
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表 2 2000—2018年研究区MS≥5.0地震的基本信息
Table 2 The general information of MS≥5.0 earthquakes from 2000 to 2018 in the studied area
序号 发震时间
年-月-日东经/° 北纬/° MS 地点 1 2001-05-24 100.90 27.63 5.8 宁蒗 2 2001-10-27 100.57 26.23 6.0 永胜 3 2009-07-10 101.05 25.55 5.2 姚安 4 2009-11-02 100.70 25.95 5.0 宾川 5 2012-06-24 100.70 27.70 5.7 宁蒗 6 2013-03-03 99.78 25.93 5.5 洱源 7 2013-04-17 99.80 25.90 5.0 洱源 8 2016-05-18 99.53 26.09 5.0 云龙 9 2017-03-27 99.80 25.89 5.1 漾濞
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崔效锋,谢富仁,张红艳. 2006. 川滇地区现代构造应力场分区及动力学意义[J]. 地震学报,28(5):451–461. doi: 10.3321/j.issn:0253-3782.2006.05.001 Cui X F,Xie F R,Zhang H Y. 2006. Recent tectonic stress field zoning in Sichuan-Yunnan region and its dynamic interest[J]. Acta Seismologica Sinica,28(5):451–461 (in Chinese).
付虹,王绍晋,王赟赟,黄毓珍,龙晓帆. 2004. 1999年至2001年云南几次中强震前应力场方向动态变化及其预测意义[J]. 地震研究,27(增刊1):7–13. Fu H,Wang S J,Wang Y Y,Huang Y Z,Long X F. 2004. The dynamic variation of the stress field before several mid-strong earthquakes from 1999 to 2001 in Yunnan and its prediction significance[J]. Journal of Seismological Research,27(S1):7–13 (in Chinese).
郭祥云,陈学忠,王生文,王恒信. 2014. 川滇地区中小地震震源机制解及构造应力场的研究[J]. 地震工程学报,36(3):599–607. doi: 10.3969/j.issn.1000-0844.2014.03.0599 Guo X Y,Chen X Z,Wang S W,Wang H X. 2014. Focal mechanism of small and moderate earthquakes and tectonic stress field in Sichuan-Yunnan areas[J]. China Earthquake Engineering Journal,36(3):599–607 (in Chinese).
韩晓明,荣代潞. 2015. 美国南加州地区1981—2011年MW≥6.0地震前发震应力场与构造应力场趋于一致现象研究[J]. 地震学报,37(6):948–958. doi: 10.11939/jass.2015.06.006 Han X M,Rong D L. 2015. Consistency of seismogenic stress field of preshocks to the tectonic stress field before eight earthquakes (MW≥6.0) in southern California of United States from 1981 to 2011[J]. Acta Seismologica Sinica,37(6):948–958 (in Chinese).
阚荣举,王绍晋,黄崐,宋文. 1983. 中国西南地区现代构造应力场与板内断块相对运动[J]. 地震地质,5(2):79–90. Kan R J,Wang S J,Huang K,Song W. 1983. Modern tectonic stress field and relative motion of intraplate block in southwestern China[J]. Seismology and Geology,5(2):79–90 (in Chinese).
李金,周龙泉,龙海英,聂晓红,郭寅. 2015. 天山地震带(中国境内)震源机制一致性参数的时空特征[J]. 地震地质,37(3):792–803. doi: 10.3969/j.issn.0253-4967.2015.03.010 Li J,Zhou L Q,Long H Y,Nie X H,Guo Y. 2015. Spatial-temporal characteristics of the focal mechanism consistency parameter in Tianshan (within Chinese territory) seismic zone[J]. Seismology and Geology,37(3):792–803 (in Chinese).
李君,王勤彩,崔子健,张佩,周琳,周辉. 2019. 川滇菱形块体东边界及邻区震源机制解与构造应力场空间分布特征[J]. 地震地质,41(6):1395–1412. doi: 10.3969/j.issn.0253-4967.2019.06.006 Li J,Wang Q C,Cui Z J,Zhang P,Zhou L,Zhou H. 2019. Characteristics of focal mechanisms and stress field in the eastern boundary of Sichuan-Yunnan block and its adjacent area[J]. Seismology and Geology,41(6):1395–1412 (in Chinese).
李泽潇,万永革,崔华伟,李振月,胡晓辉,黄骥超,靳志同. 2020. 2018年9月8日墨江地震及周边地区构造应力场特征分析[J]. 地球物理学报,63(4):1431–1443. doi: 10.6038/cjg2020N0155 Li Z X,Wan Y G,Cui H W,Li Z Y,Hu X H,Huang J C,Jin Z T. 2020. Characteristics analysis of tectonic stress field around the Mojiang earthquake and its adjacent areas on September 8,2018[J]. Chinese Journal of Geophysics,63(4):1431–1443 (in Chinese).
刘方斌,曲均浩,李国一,田兆阳. 2018. 山东长岛震群震源机制解一致性参数时空演化特征[J]. 地震工程学报,40(5):1034–1041. doi: 10.3969/j.issn.1000-0844.2018.05.1034 Liu F B,Qu J H,Li G Y,Tian Z Y. 2018. Spatial-temporal characteristics of the focal mechanism solutions consistency parameter of Changdao earthquake swarm[J]. China Earthquake Engineering Journal,40(5):1034–1041 (in Chinese).
刘自凤,付虹,彭关灵,赵小艳,李孝宾,茶文剑. 2020. 2014年云南3次强震前后震源机制一致性时空演化特征[J]. 地震研究,43(2):348–354. doi: 10.3969/j.issn.1000-0666.2020.02.017 Liu Z F,Fu H,Peng G L,Zhao X Y,Li X B,Cha W J. 2020. Temporal and spatial evolutionary characteristics of focal mechanism consistency before and after three strong earthquakes in Yunnan in 2014[J]. Journal of Seismological Research,43(2):348–354 (in Chinese).
罗钧,赵翠萍,周连庆. 2014. 川滇块体及周边区域现今震源机制和应力场特征[J]. 地震地质,36(2):405–421. doi: 10.3969/j.issn.0253-4967.2014.02.011 Luo J,Zhao C P,Zhou L Q. 2014. Characteristics of focal mechanisms and stress field of the Chuan-Dian rhombic block and its adjacent regions[J]. Seismology and Geology,36(2):405–421 (in Chinese).
钱晓东,秦嘉政,刘丽芳. 2011. 云南地区现代构造应力场研究[J]. 地震地质,33(1):91–106. doi: 10.3969/j.issn.0253-4967.2011.01.009 Qian X D,Qin J Z,Liu L F. 2011. Study on recent tectonic stress field in Yunnan region[J]. Seismology and Geology,33(1):91–106 (in Chinese).
孙业君,赵小艳,黄耘,杨浩,李锋. 2017. 云南地区震源机制及应力场特征[J]. 地震地质,39(2):390–407. doi: 10.3969/j.issn.0253-4967.2017.02.009 Sun Y J,Zhao X Y,Huang Y,Yang H,Li F. 2017. Characteristics of focal mechanisms and stress field of Yunnan area[J]. Seismology and Geology,39(2):390–407 (in Chinese).
田优平,唐红亮,康承旭,万永革,黄骥超,姚海东,佘旭明. 2020. 综合震源机制解法反演湖南地区构造应力场的初步结果[J]. 地球物理学报,63(11):4080–4096. doi: 10.6038/cjg2020N0061 Tian Y P,Tang H L,Kang C X,Wan Y G,Huang J C,Yao H D,She X M. 2020. Preliminary results of inversion of tectonic stress field in Hunan region by the composite focal mechanism method[J]. Chinese Journal of Geophysics,63(11):4080–4096 (in Chinese).
万永革. 2020. 震源机制与应力体系关系模拟研究[J]. 地球物理学报,63(6):2281–2296. doi: 10.6038/cjg2020M0472 Wan Y G. 2020. Simulation on relationship between stress regimes and focal mechanisms of earthquakes[J]. Chinese Journal of Geophysics,63(6):2281–2296 (in Chinese).
吴大宁, 邓起东. 1985. 滇西北裂陷区的基本特征及其形成机制[G]//现代地壳运动研究（1）. 北京: 地震出版社: 118–132. Wu D N, Deng Q D. 1985. The basic characteristics and formation mechanism of the rifted area in northwestern Yunnan[G]//Modern Crustal Movement Research （1）. Beijing: Seismological Press: 118–132 （in Chinese）.
吴中海,龙长兴,范桃园,周春景,冯卉,杨振宇,仝亚博. 2015. 青藏高原东南缘弧形旋扭活动构造体系及其动力学特征与机制[J]. 地质通报,34(1):1–31. doi: 10.3969/j.issn.1671-2552.2015.01.002 Wu Z H,Long C X,Fan T Y,Zhou C J,Feng H,Yang Z Y,Tong Y B. 2015. The arc rotational-shear active tectonic system on the southeastern margin of Tibetan Plateau and its dynamic characteristics and mechanism[J]. Geological Bulletin of China,34(1):1–31 (in Chinese).
向宏发,虢顺民,冉勇康,李祥根,张靖,陈铁牛,张国伟. 1986. 滇西北地区的现代构造应力场[J]. 地震地质,8(4):15–23. Xiang H F,Guo S M,Ran Y K,Li X G,Zhang J,Chen T N,Zhang G W. 1986. Recent tectonic stress field in the northwest of the Yunnan Province[J]. Seismology and Geology,8(4):15–23 (in Chinese).
谢富仁,刘光勋,梁海庆. 1994. 滇西北及邻区现代构造应力场[J]. 地震地质,16(4):329–338. Xie F R,Liu G X,Liang H Q. 1994. Recent tectonic stress field in northwest Yunnan Province and its adjacent areas[J]. Seismology and Geology,16(4):329–338 (in Chinese).
徐彦, 李丹宁. 2016. 云南地区ML3.0级以上中小地震震源机制解汇编[M]. 昆明: 云南科技出版社: 168–186. Xu Y, Li D N. 2016. The Compilation of Focal Mechanism of Small and Medium Earthquakes Above ML3.0 in Yunnan Area[M]. Kunming: Yunnan Science and Technology Press: 168–186 （in Chinese）.
许忠淮,戈澍谟. 1984. 用滑动方向拟合法反演富蕴地震断裂带应力场[J]. 地震学报,6(4):395–404. Xu Z H,Ge S M. 1984. Stress field in the Fuyun,Xinjiang earthquake fracture zone determined by fitting fault slip vector data[J]. Acta Seismologica Sinica,6(4):395–404 (in Chinese).
许忠淮. 1985. 用滑动方向拟合法反演唐山余震区的平均应力场[J]. 地震学报,7(4):349–362. Xu Z H. 1985. Mean stress field in Tangshan aftershock area obtained from focal mechanism data by fitting slip directions[J]. Acta Seismologica Sinica,7(4):349–362 (in Chinese).
张智奇,姚华建,杨妍. 2020. 青藏高原东南缘地壳上地幔三维S波速度结构及动力学意义[J]. 中国科学:地球科学,50(9):1242–1258. Zhang Z Q,Yao H J,Yang Y. 2020. Shear wave velocity structure of the crust and upper mantle in southeastern Tibet and its geodynamic implications[J]. Science China Earth Sciences,63(9):1278–1293. doi: 10.1007/s11430-020-9625-3
张致伟,周龙泉,龙锋,阮祥. 2015. 汶川8.0和芦山7.0级地震序列应力场时空特征[J]. 地震地质,37(3):804–817. doi: 10.3969/j.issn.0253-4967.2015.03.011 Zhang Z W,Zhou L Q,Long F,Ruan X. 2015. Spatial and temporal characteristic of stress field for Wenchuan MS8.0 and Lushan MS7.0 earthquake sequence[J]. Seismology and Geology,37(3):804–817 (in Chinese).
Audemard F A,Romero G,Rendon H,Cano V. 2005. Quaternary fault kinematics and stress tensors along the southern Caribbean from fault-slip data and focal mechanism solutions[J]. Earth-Sci Rev,69(3/4):181–233.
Bohnhoff M,Grosser H,Dresen G. 2006. Strain partitioning and stress rotation at the North Anatolian fault zone from aftershock focal mechanisms of the 1999 Izmit MW=7.4 earthquake[J]. Geophys J Int,166(1):373–385. doi: 10.1111/j.1365-246X.2006.03027.x
Ellsworth W L. 1981. A general theory for determining the state of stress in the earth from fault slip measurements[J]. Terra Congn,2(2):170–171.
Gephart J W,Forsyth D W. 1984. An improved method for determining the regional stress tensor using earthquake focal mechanism data:Application to the San Fernando earthquake sequence[J]. J Geophys Res,89(B11):9305–9320. doi: 10.1029/JB089iB11p09305
Hardebeck J L,Michael A J. 2006. Damped regional-scale stress inversions:Methodology and examples for southern California and the Coalinga aftershock sequence[J]. J Geophys Res,111(B11):B11310.
Lu Z,Wyss M,Pulpan H. 1997. Details of stress directions in the Alaska subduction zone from fault plane solutions[J]. J Geophys Res,102(B3):5385–5402. doi: 10.1029/96JB03666
Michael A J. 1984. Determination of stress from slip data:Faults and folds[J]. J Geophys Res,89(B13):11517–11526. doi: 10.1029/JB089iB13p11517
Michael A J. 1987. Use of focal mechanisms to determine stress:A control study[J]. J Geophys Res,92(B1):357–368. doi: 10.1029/JB092iB01p00357
Michael A J. 1991. Spatial variations in stress within the 1987 Whittier Narrows,California,aftershock sequence:New techniques and results[J]. J Geophys Res,96(B4):6303–6319. doi: 10.1029/91JB00195
Wan Y G,Sheng S Z,Huang J C,Li X,Chen X. 2016. The grid search algorithm of tectonic stress tensor based on focal mechanism data and its application in the boundary zone of China,Vietnam and Laos[J]. J Earth Sci,27(5):777–785. doi: 10.1007/s12583-015-0649-1
Wessel P,Smith W H F. 1995. New version of the generic mapping tools[J]. Eos Trans Am Geophys Un,76(33):329.
Wiemer S,Malone S. 2001. A software package to analyze seismicity:ZMAP[J]. Seismol Res Lett,72(3):373–382. doi: 10.1785/gssrl.72.3.373
Zhang P Z,Shen Z K,Wang M,Gan W J,Bürgmann R,Molnar P,Wang Q,Niu Z J,Sun J Z,Wu J C,Sun H R,You X Z. 2004. Continuous deformation of the Tibetan Plateau from global positioning system data[J]. Geology,32(9):809–812. doi: 10.1130/G20554.1
Zhao L,Luo Y,Liu T Y,Luo Y J. 2013. Earthquake focal mechanisms in Yunnan and their inference on the regional stress field[J]. Bull Seismol Soc Am,103(4):2498–2507. doi: 10.1785/0120120309
Zoback M L. 1992. First- and second-order patterns of stress in the lithosphere: The World Stress Map project[J]. J Geophys Res,97(B8):11703–11728.
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