Coseismic and postseismic deformation of the 2001 MW7.8 Kunlun Mountain earthquake and its loading effect on the 2021 MW7.3 Madoi earthquake
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摘要:
位于青藏高原中北部的巴颜喀拉地块是我国西部近年来的主体地震活动区，一系列MW7.0以上强震均发生在该次级块体周边，而其北边界东昆仑断裂带是一条长达2000 km、规模最大、活动性最强的深大断裂带.2001年在东昆仑断裂带中段发生了MW7.8昆仑山地震，2021年5月在其震中东南部大约450 km处巴颜喀拉块体内部一次级断裂上发生了MW7.3玛多地震.玛多地震对人们以往认为强震更可能发生在巴颜喀拉块体边界断裂上的认识提出挑战，但是也为研究巴颜喀拉块体边界断裂与块体内部次级断裂活动关系、地震触发关系带来机遇.本文利用前期基于2001年昆仑山地震后积累的大量InSAR数据获得的震后大范围形变场时空演化图像和库仑应力变化模型，探讨昆仑山地震与玛多地震的关系.InSAR震后观测结果显示：昆仑山地震后沿东昆仑断裂带出现了长达500 km的大范围南北不对称震后形变场，其中南盘形变宽度和量级均明显大于北盘，南盘形变宽度达到250 km，断层近场相对平均形变速率达到＞20 mm·a-1，而且南盘向南衰减梯度小，整体衰减缓慢，意味着震后形变对巴颜喀拉块体形成持续东向加载作用，并将分摊到块体内部的一系列次级断裂上，应力加载增加次级断层的地震危险性.2015—2020年InSAR震间应变率场则显示次级断裂——昆仑山口—江错断裂呈高剪切应变率特征.本文计算了昆仑山地震同震破裂和震后形变引起的玛多震区多条SE向次级断裂的累积库仑应力变化，结果显示昆仑山地震同震和震后形变对玛多地震发震断裂(昆仑山口—江错断裂)形成了一定的应力加载.本文认为昆仑山地震同震和长时间尺度震后形变加速了巴颜喀拉块体的东向运动，而断层本身运动学性质和区域应力扰动共同影响了玛多地震的发生.
Abstract:The Bayan Har block in the north-central Tibetan Plateau has been the main seismic region in west China in recent years, and a series of major earthquakes with MW > 7.0 have occurred around this block. Its northern boundary, the East Kunlun fault, is an active large-scale fault zone with a total length of ~2000 km. The 2001 MW7.8 Kunlun Mountain(Hoh Xil)earthquake occurred in the middle segment of the East Kunlun fault(or Kunlun fault), and the MW7.3 Madoi earthquake occurred on a secondary fault inside the Bayan Har block, ~450 km southeast of the Kunlun Mountain earthquake. The Madoi earthquake challenges the previous long-held view that strong earthquakes are more likely to occur on the boundary faults of the Bayan Har block. This earthquake also provides an opportunity to study the relationship among the boundary faults and secondary faults, and earthquakes triggering within the block. This paper explores the potential relationship between the Kunlun Mountain earthquake and the Madoi earthquake using postseismic InSAR observations and the Coulomb stress change, which are obtained from a large amount of SAR data acquired after the Kunlun Mountain earthquake. The InSAR postseismic deformation shows a widespread asymmetric pattern along the rupture zone, and the deformation width and magnitude of the southern part are significantly larger than the northern one. The deformation width of the southern part reaches 250 km, and the near-field deformation rate reaches > 20 mm·a-1. The decay of displacement rate on the southern part is insignificant, implying that the postseismic deformation forms a enduring eastward loading effect on the Bayan Har block, and will be partitioned into a series of secondary faults inside the block. The stress loading increases the seismic potential of the secondary faults. The interseismic strain map during 2015—2020 shows a high strain rate zone along the secondary fault, the Kunlun Mountain Pass—Jiangcuo fault. We calculate the cumulative Coulomb stress change caused by the coseismic rupture and postseismic processes of the Kunlun Mountain earthquake. The results show that the stress variation on the seismogenic fault of the Madoi earthquake, the Kunlun Pass—Jiangcuo Fault, is significant. Based on these results, we suggest that the coseismic and postseismic deformation of the Kunlun Mountain earthquake may enhance the eastward motion of the Bayan Har block and thus contribute to the occurrence of the Madoi earthquake.
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图 1
巴颜喀拉地块及周边区域地震构造背景略图
Figure 1.
Tectonic background of the Bayan Har block and its surrounding areas
图 2
地质学及GPS观测得到的东昆仑断裂带沿断层走向滑动速率(修改自Zhao et al., 2022)
Figure 2.
Fault slip rates along the strike of the East Kunlun fault, suggested by geological investigations and GPS observations (modified from Zhao et al., 2022)
图 3
昆仑山地震震中区(T133条带)不同时段平均震后形变速率时空演化
Figure 3.
Temporal and spatial evolution of the average postseismic displacement rate in different periods around the epicentral area of the Kunlun Mountain earthquake (T133)
图 4
昆仑山地震震中区(T133条带)震后不同阶段3年时窗跨断层累积形变量(2003—2010年)
Figure 4.
Cumulative fault-perpendicular displacement (T133) using a 3-year time window in different stages after the Kunlun Mountain earthquake epicentral area (2003—2010)
图 5
昆仑山地震破裂带东端断层分叉处(T90条带)不同时段震后平均形变速率
Figure 5.
Average post-seismic displacement rate at fault bifurcation (T90 strip) around the eastern end of the coseismic rupture zone in different periods
图 6
昆仑山地震破裂带东端断层分叉处(T90条带)不同时段震后平均形变速率剖面
Figure 6.
Profiles of average postseismic displacement rate (T90) at the fault bifurcation around the eastern end of the coseismic rupture in different periods
图 7
昆仑山地震震后累积形变场(2003—2010年)与2021年玛多地震同震形变空间分布关系
Figure 7.
Spatial distribution relationship between cumulative postseismic displacement field of the Kunlun Mountain earthquake (2003—2010) and coseismic deformation of the 2021 Madoi earthquake
图 8
基于哨兵数据的东昆仑断裂带形变速率场和应变率场(时间范围：2015—2020年)
Figure 8.
Velocity field and strain rate field of the East Kunlun fault zone observed by Sentinel-1 data (time window: 2015—2020)
图 9
玛多地震前震源区升降轨InSAR形变速率场(2015—2020)
Figure 9.
Ascending and descending InSAR velocity field in the epicentral area prior to the Madoi earthquake (2015—2020)
图 10
同震和震后库仑应力模型计算采用的7条断层空间位置
Figure 10.
Location of 7 faults used in coseismic and post-seismic Coulomb stress change calculation
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Barbot S, Fialko Y, Bock Y. 2009. Postseismic deformation due to the MW6.0 2004 Parkfield earthquake: Stress-driven creep on a fault with spatially variable rate-and-state friction parameters. Journal of Geophysical Research: Solid Earth, 114(B7): B07405, doi: 10.1029/2008JB005748.
Chen H, Qu C Y, Zhao D Z, et al. 2021. Rupture Kinematics and Coseismic Slip Model of the 2021 MW7.3 Maduo(China)Earthquake: Implications for the Seismic Hazard of the Kunlun Fault. Remote Sensing, 13(16): 3327, doi: 10.3390/rs13163327.
Chen J, Chen Y K, Ding G Y, et al. 2004. Surficial slip distribution and segmentation of the 426-km-long surface rupture of the 14 November, 2001, MS8.1 earthquake on the east Kunlun fault, northern Tibetan Plateau, China. Seismology and Geology(in Chinese), 26(3): 378-392.
Cheng J, Xu X W. 2018. Features of earthquake clustering from calculation of coulomb stress around the Bayan Har block, Tibetan Plateau. Seismology and Geology(in Chinese), 40(1): 133-154, doi: 10.3969/j.issn.0253-4967.2018.01.011.
Deng Q D, Cheng S P, Ma J, et al. 2014. Seismic activities and earthquake potential in the Tibetan Plateau. Chinese Journal of Geophysics(in Chinese), 57(7): 2025-2042, doi: 10.6038/cjg20140701.
Diao F Q, Xiong X, Wang R J, et al. 2019. Slip rate variation along the Kunlun Fault(Tibet): Results from new GPS observations and a viscoelastic earthquake-cycle deformation model. Geophysical Research Letters, 46(5): 2524-2533, doi: 10.1029/2019GL081940.
Garthwaite M C, Wang H, Wright T J. 2013. Broadscale interseismic deformation and fault slip rates in the central Tibetan Plateau observed using InSAR. Journal of Geophysical Research: Solid Earth, 118(9): 5071-5083, doi: 10.1002/jgrb.50348.
He J K, Chéry J. 2008. Slip rates of the Altyn Tagh, Kunlun and Karakorum faults(Tibet)from 3D mechanical modeling. Earth and Planetary Science Letters, 274(1-2): 50-58, doi: 10.1016/j.epsl.2008.06.049.
He K F, Wen Y M, Xu C J, et al. 2022. Fault geometry and slip distribution of the 2021 MW7.4 Maduo, China, Earthquake inferred from InSAR measurements and relocated aftershocks. Seismological Research Letters, 93(1): 8-20, doi: 10.1785/0220210204.
He L J, Feng G C, Wu X X, et al. 2021. Coseismic and early postseismic slip models of the 2021 MW7.4 Maduo Earthquake(Western China)estimated by space-based geodetic data. Geophysical Research Letters, 48(24): e2021GL095860, doi: 10.1029/2021GL095860.
Jin Z Y, Fialko Y. 2021. Coseismic and early postseismic deformation due to the 2021 M7.4 Maduo(China)Earthquake. Geophysical Research Letters, 48(21): e2021GL095213, doi: 10.1029/2021GL095213.
Kirby E, Harkins N, Wang E Q, et al. 2007. Slip rate gradients along the eastern Kunlun fault. Tectonics, 26(2): TC2010, doi: 10.1029/2006TC002033.
Klinger Y, Michel R, King G C P. 2006. Evidence for an earthquake barrier model from MW~7.8 Kokoxili(Tibet)earthquake slip-distribution. Earth and Planetary Science Letters, 242(3-4): 354-364, doi: 10.1016/j.epsl.2005.12.003.
Lasserre C, Peltzer G, Crampé F, et al. 2005. Coseismic deformation of the 2001 MW=7.8 Kokoxili earthquake in Tibet, measured by synthetic aperture radar interferometry. Journal of Geophysical Research: Solid Earth, 110(B12): B12408, doi: 10.1029/2004JB003500.
Li Y H, Liu M, Wang Q L, et al. 2018. Present-day crustal deformation and strain transfer in northeastern Tibetan Plateau. Earth and Planetary Science Letters, 487: 179-189, doi: 10.1016/j.epsl.2018.01.024.
Liang M J, Yang Y, Du F, et al. 2020. Late quaternary activity of the central segment of the Dari fault and restudy of the surface rupture zone of the 1947 M7¾ Dari earthquake, Qinghai province. Seismology and Geology(in Chinese), 42(3): 703-714, doi: 10.3969/j.issn.0253-4967.2020.03.011.
Loveless J P, Meade B J. 2011. Partitioning of localized and diffuse deformation in the Tibetan Plateau from joint inversions of geologic and geodetic observations. Earth and Planetary Science Letters, 303(1-2): 11-24, doi: 10.1016/j.epsl.2010.12.014.
Molnar P, Tapponnier P. 1978. Active tectonics of Tibet. Journal of Geophysical Research: Solid Earth, 83(B11): 5361-5375, doi: 10.1029/JB083iB11p05361.
Parizzi A, Brcic R, De Zan F. 2021. InSAR performance for large- scale deformation measurement. IEEE Transactions on Geoscience and Remote Sensing, 59(10): 8510-8520, doi: 10.1109/TGRS.2020.3039006.
Ren J J, Xu X W, Yeats R S, et al. 2013. Millennial slip rates of the Tazang fault, the eastern termination of Kunlun fault: Implications for strain partitioning in eastern Tibet. Tectonophysics, 608: 1180-1200, doi: 10.1016/j.tecto.2013.06.026.
Ryder I, Parsons B, Wright T J, et al. 2007. Post-seismic motion following the 1997 Manyi(Tibet)earthquake: InSAR observations and modelling. Geophysical Journal International, 169(3): 1009-1027, doi: 10.1111/j.1365-246X.2006.03312.x.
Shan B, Xiong X, Wang R J, et al. 2015. Stress evolution and seismic hazard on the Maqin-Maqu segment of East Kunlun Fault zone from co-, post- and interseismic stress changes. Geophysical Journal International, 200(1): 244-253, doi: 10.1093/gji/ggu395.
Shan X J, Qu C Y, Gong W Y, et al. 2017. Coseismic deformation field of the Jiuzhaigou MS7.0 earthquake from Sentinel-1A InSAR data and fault slip inversion. Chinese Journal of Geophysics(in Chinese), 60(12): 4527-4536, doi: 10.6038/cjg20171201.
Tapponnier P, Peltzer G, Le Dain A Y, et al. 1982. Propagating extrusion tectonics in Asia: New insights from simple experiments with plasticine. Geology, 10(12): 611-616, doi: 10.1130/0091-7613(1982)10〈611:PETIAN〉2.0.CO;2.
Van der Woerd J, Ryerson F J, Tapponnier P, et al. 2000. Uniform slip-rate along the Kunlun Fault: Implications for seismic behaviour and large-scale tectonics. Geophysical Research Letters, 27(16): 2353-2356, doi: 10.1029/1999GL011292.
Van Der Woerd J, Tapponnier P, Ryerson F J, et al. 2002. Uniform postglacial slip-rate along the central 600 km of the Kunlun Fault(Tibet), from 26Al, 10Be, and 14C dating of riser offsets, and climatic origin of the regional morphology. Geophysical Journal International, 148(3): 356-388, doi: 10.1046/j.1365-246x.2002.01556.x.
Wan Y G, Shen Z K, Gan W J, et al. 2003. Study on the elastic stress triggering among the large earthquakes in eastern Kunlun active fault zone. Northwestern Seismological Journal(in Chinese), 25(1): 1-7, doi: 10.3969/j.issn.1000-0844.2003.01.001.
Wang H, Wright T J, Jing L Z, et al. 2019. Strain rate distribution in South-Central Tibet from two decades of InSAR and GPS. Geophysical Research Letters, 46(10): 5170-5179, doi: 10.1029/2019GL081916.
Wang M, Shen Z K. 2020. Present-day crustal deformation of continental China derived from GPS and its tectonic implications. Journal of Geophysical Research: Solid Earth, 125(2): e2019JB018774, doi: 10.1029/2019JB018774.
Wang S, Song C, Li S S, et al. 2022. Resolving co- and early post-seismic slip variations of the 2021 MW7.4 Madoiearthquake in east Bayan Har block with a block-wide distributed deformation mode from satellite synthetic aperture radar data. Earth Planet. Phys. , 6(1): 108-122, doi: 10.26464/epp2022007.
Weiss J R, Walters R J, Morishita Y, et al. 2020. High-resolution surface velocities and strain for anatolia from Sentinel-1 InSAR and GNSS data. Geophysical Research Letters, 47(17): e2020GL087376, doi: 10.1029/2020GL087376.
Wen Y M, Li Z H, Xu C J, et al. 2012. Postseismic motion after the 2001 MW7.8 Kokoxili earthquake in Tibet observed by InSAR time series. Journal of Geophysical Research: Solid Earth, 117(B8): B08405, doi: 10.1029/2011JB009043.
Wessel P, Luis J F. 2017. The GMT/MATLAB toolbox. Geochemistry, Geophysics, Geosystems, 18(2): 811-823, doi: 10.1002/2016GC006723.
Xiong X, Shan B, Zheng Y, et al. 2010. Stress transfer and its implication for earthquake hazard on the Kunlun Fault, Tibet. Tectonophysics, 482(1-4): 216-225, doi: 10.1016/j.tecto.2009.07.020.
Xu X W, Chen W B, Yu G H, et al. 2002. Characteristic features of the surface ruptures of the Hoh Sai Hu(Kunlunshan)earthquake(MS8.1), northern Tibetan Plateau, China. Seismology and Geology(in Chinese), 24(1): 1-13.
Yang G H, Zhang X D, Zhang F S, et al. 2008. The variation characteristics of the crust horizontal displacement field in the West of China after Kunlun Mountain MS8.1 earthquake. Journal of Seismological Research(in Chinese), 31(1): 77-82.
Yuan Z D, Li T, Su P, et al. 2022. Large surface-rupture gaps and low surface fault slip of the 2021 MW7.4 Maduo Earthquake along a low-activity strike-slip fault, Tibetan Plateau. Geophysical Research Letters, 49(6): e2021GL096874, doi: 10.1029/2021GL096874.
Zhan Y, Liang M J, Sun X Y, et al. 2021. Deep structure and seismogenic pattern of the 2021.5.22 Madoi(Qinghai)MS7.4 earthquake. Chinese Journal of Geophysics(in Chinese), 64(7): 2232-2252, doi: 10.6038/cjg2021O0521.
Zhang P Z, Deng Q D, Zhang G M, et al. 2003. Strong earthquakes and active-tectonic blocks in China mainland. Science in China Series D: Earth Sciences, 46(S2): 13-24.
Zhang P Z, Shen Z K, Wang M, et al. 2004. Continuous deformation of the Tibetan Plateau from global positioning system data. Geology, 32(9): 809-812, doi: 10.1130/g20554.1.
Zhao D Z, Qu C Y, Bürgmann R, et al. 2021. Relaxation of Tibetan lower crust and afterslip driven by the 2001 MW7.8 Kokoxili, China, Earthquake constrained by a decade of geodetic measurements. Journal of Geophysical Research: Solid Earth, 126(4): e2020JB021314, doi: 10.1029/2020JB021314.
Zhao D Z, Qu C Y, Bürgmann R, et al. 2022. Large-scale crustal deformation, slip-rate variation, and strain distribution along the Kunlun Fault(Tibet)from Sentinel-1 InSAR observations(2015—2020). Journal of Geophysical Research: Solid Earth, 127(1): e2021JB022892, doi: 10.1029/2021JB022892.
Zheng W J, Yuan D Y, Zhang P Z, et al. 2016. Tectonic geometry and kinematic dissipation of the active faults in the northeastern Tibetan Plateau and their implications for understanding northeastward growth of the plateau. Quaternary Sciences(in Chinese), 36(4): 775-788, doi: 10.11928/j.issn.1001-7410.2016.04.01.
陈杰, 陈宇坤, 丁国瑜等. 2004. 2001年昆仑山口西MS8.1地震地表同震位移分布特征. 地震地质, 26(3): 378-392. doi: 10.3969/j.issn.0253-4967.2004.03.003
程佳, 徐锡伟. 2018. 巴颜喀拉块体周缘强震间应力作用与丛集活动特征初步分析. 地震地质, 40(1): 133-154, doi: 10.3969/j.issn.0253-4967.2018.01.011.
邓起东, 程绍平, 马冀等. 2014. 青藏高原地震活动特征及当前地震活动形势. 地球物理学报, 57(7): 2025-2042, doi: 10.6038/cjg20140701. http://www.geophy.cn/article/doi/10.6038/cjg20140701
梁明剑, 杨耀, 杜方等. 2020. 青海达日断裂中段晚第四纪活动性与1947年M7¾地震地表破裂带再研究. 地震地质, 42(3): 703-714, doi: 10.3969/j.issn.0253-4967.2020.03.011.
单新建, 屈春燕, 龚文瑜等. 2017. 2017年8月8日四川九寨沟7.0级地震InSAR同震形变场及断层滑动分布反演. 地球物理学报, 60(12): 4527-4536, doi: 10.6038/cjg20171201. http://www.geophy.cn/article/doi/10.6038/cjg20171201
万永革, 沈正康, 甘卫军等. 2003. 东昆仑活动断裂带大地震之间的弹性应力触发研究. 西北地震学报, 25(1): 1-7, doi: 10.3969/j.issn.1000-0844.2003.01.001.
徐锡伟, 陈文彬, 于贵华等. 2002. 2001年11月14日昆仑山库赛湖地震(MS8.1)地表破裂带的基本特征. 地震地质, 24(1): 1-13. https://www.cnki.com.cn/Article/CJFDTOTAL-DZDZ200201000.htm
杨国华, 张晓东, 张风霜等. 2008. 昆仑山口西8.1级地震震后中国西部地壳水平位移场的变化特征. 地震研究, 31(1): 77-82. https://www.cnki.com.cn/Article/CJFDTOTAL-DZYJ200801014.htm
詹艳, 梁明剑, 孙翔宇等. 2021. 2021年5月22日青海玛多MS7.4地震深部环境及发震构造模式. 地球物理学报, 64(7): 2232-2252, doi: 10.6038/cjg2021O0521. http://www.geophy.cn/article/doi/10.6038/cjg2021O0521
张培震, 邓起东, 张国民等. 2003. 中国大陆的强震活动与活动地块. 中国科学: D辑, 33(S1): 12-20, doi: 10.3321/j.issn:1006-9267.2003.z1.002.
郑文俊, 袁道阳, 张培震等. 2016. 青藏高原东北缘活动构造几何图像、运动转换与高原扩展. 第四纪研究, 36(4): 775-788, doi: 10.11928/j.issn.1001-7410.2016.04.01.
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