地震研究

甘孜—玉树—鲜水河断裂带是青藏高原重要的大型边界走滑断裂,基于GNSS数据约束该断裂带的现今滑动速率有助于认识其活动习性,便于探讨其现今变形特征与模式。利用GNSS速度场横跨甘孜—玉树—鲜水河断裂带构建了7个速率剖面,获取该断裂带滑动速率变化。结果表明:该断裂带现今左旋滑动速率由NW向SE逐渐增大,其中,甘孜—玉树断裂走滑速率为4.9 mm/a,鲜水河断裂北西段走滑速率为9.5 mm/a,其东段的康定—石棉段滑动速率增加至10 mm/a,再向南至安宁河—则木河和大凉山断裂,剪切速率基本保持在10 mm/a左右。甘孜—玉树断裂水平缩短速率为2～4 mm/a,向东至鲜水河断裂和安宁河断裂水平缩短较弱,而大凉山断裂具有约为2 mm/a的地壳缩短变形,则木河断裂有约为1 mm/a的拉张速率。这一结果表明:甘孜—玉树—鲜水河断裂带的现今滑动速率远低于此前的认识,“连续变形”理论模型可能更适用于大陆内部的构造变形。

The Ganzi-Yushu-Xianshuihe Fault Zone is an important large-scale boundary slip fault on the Tibetan Plateau.The present-day slip rate constraining this fault zone calculated according to GNSS data can help understand the fault zone's activity behaviour and explore the fault zone's present-day deformation characteristics and deformation patterns.On the basis of the GNSS velocity field,seven rate profiles across the Ganzi-Yushu-Xianshuihe Fault Zone are constructed,and main conclusions are as follows:The present-day,left-lateral,strike-slip rate of the Ganzi-Yushu-Xianshuihe Fault Zone gradually increases from Northwest direction towards Southeast direction.The Ganzi-Yushu Fault slips at the rate of 4.9 mm/a.The Northwest segment of the Xianshuihe Fault slips at the rate of 9.5 mm/a.The eastern segment of the Xianshuihe Fault,namely the Kangding-Shimian Fault,slips at a rate of 10 mm/a.In the Anninghe-Zemuhe Fault and the Daliangshan Fault,the shear rate is about 10 mm/a.Meanwhile,in the Ganzi-Yushu Fault,the Crust's shrinking rate is 2-4 mm/a.The Daliangshan Fault Zone undergoes crustal shrinking at the rate of about 2 mm/a,and the Zemuhe Fault has a tensile rate of about 1 mm/a.This reveals that the present-day slip rate of the Ganzi-Yushu-Xianshuihe Fault is much lower than the previous research results,and the theoretical model of “continuous deformation” may be more suitable for researching the tectonic deformation of the interior continent.

引言
1 区域地质概况
2 数据与方法
3 结果分析
4 结论

图1 甘孜—玉树—鲜水河断裂带地区主要活动断裂分布以及GNSS速率剖面位置<br/>Fig.1 Major active faults in the Ganzi-Yushu-Xianshuihe fault zone area and the location of the GNSS velocity' profiles

图1 甘孜—玉树—鲜水河断裂带地区主要活动断裂分布以及GNSS速率剖面位置
Fig.1 Major active faults in the Ganzi-Yushu-Xianshuihe fault zone area and the location of the GNSS velocity' profiles

图2 横跨风火山断裂(a)、甘孜—玉树断裂(b)及鲜水河断裂(c)的速率剖面以及平行于和垂直于断层的GNSS速率分量<br/>Fig.2 The profiles across the Fenghuoshan Fault(a),the Ganzi-Yushu Fault(b)and the Xianshuihe Fault(c),and the GNSS velocity components parallel and perpendicular to the faults

图2 横跨风火山断裂(a)、甘孜—玉树断裂(b)及鲜水河断裂(c)的速率剖面以及平行于和垂直于断层的GNSS速率分量
Fig.2 The profiles across the Fenghuoshan Fault(a),the Ganzi-Yushu Fault(b)and the Xianshuihe Fault(c),and the GNSS velocity components parallel and perpendicular to the faults

图3 横跨鲜水河断裂道孚—炉霍段(a)、康定—石棉段(b)的速率剖面以及平行于和垂直于断层的GNSS速率分量<br/>Fig.3 The profiles across the Daofu-Luhuo(a)and Kangding-Shimian(b)sections of the Xianshuihe Fault,and the GNSS velocity components parallel and perpendicular to the faults

图3 横跨鲜水河断裂道孚—炉霍段(a)、康定—石棉段(b)的速率剖面以及平行于和垂直于断层的GNSS速率分量
Fig.3 The profiles across the Daofu-Luhuo(a)and Kangding-Shimian(b)sections of the Xianshuihe Fault,and the GNSS velocity components parallel and perpendicular to the faults

图4 横跨安宁河—大凉山—马边断裂(a)及则木河—大凉山断裂(b)的速率剖面以及平行于和垂直于断层的GNSS速率分量<br/>Fig.4 The profiles across the Anninghe-Daliangshan-Mabian Fault(a)and the Zemnhe-Daliangshan Fault(b),and the GNSS velocity components parallel and perpendicular to the faults

图4 横跨安宁河—大凉山—马边断裂(a)及则木河—大凉山断裂(b)的速率剖面以及平行于和垂直于断层的GNSS速率分量
Fig.4 The profiles across the Anninghe-Daliangshan-Mabian Fault(a)and the Zemnhe-Daliangshan Fault(b),and the GNSS velocity components parallel and perpendicular to the faults

陈桂华,徐锡伟,闻学泽,等.2008.川滇块体北—东边界活动构造带运动学转换与变形分解作用[J].地震地质,30(1):58-85.
Chen G H,Xu X W,Wen X Z,et al.2008.Kinematical transformation and slip partitioning of northern to eastern active boundary belt of Sichuan-Yunnan block [J].Seismology and Geology,30(1):58-85.(in Chinese)
邓起东,张培震,冉勇康,等.2003.中国活动构造与地震活动[J].地学前缘,10(S1):66-73.
Deng Q D,Zhang P Z,Ran Y K,et al.2003.Active tectonics and earthquake activities in China[J].Earth Science Frontiers,10(S1):66-73.(in Chinese)
王敏,沈正康,甘卫军,等.2008.GPS连续监测鲜水河断裂形变场动态演化[J].中国科学:地球科学,38(5):575-581.
Wang M,Shen Z K,Gan W J,et al.2008.GPS continuously monitored the dynamic evolution of deformation field of the Xianshuihe fault[J].Scientia Sinica Terrae,38(5):575-581.(in Chinese)
王敏,沈正康.2020.中国大陆现今构造变形:三十年的GPS观测与研究[J].中国地震,36(4):660-683.
Wang M,Shen Z K.2020.Present-day tectonic deformation in continental China:Thirty years of GPS observation and research[J].Earthquake Research in China,36(4):660-683.(in Chinese)
王阎昭,王恩宁,沈正康,等.2008.基于GPS资料约束反演川滇地区主要断裂现今活动速率[J].中国科学:地球科学,38(5):582-597.
Wang Y Z,Wang E N,Shen Z K,et al.2008.Constrained inversion of present-day activity rates of major faults in the Sichuan-Yunnan region from GPS data[J].Scientia Sinica Terrae,38(5):582-597.(in Chinese)
王阎昭,王敏,沈正康,等.2011.2010年玉树地震震前甘孜—玉树断裂形变场分析[J].地震地质,33(3):525-532.
Wang Y Z,Wang M,Shen Z K,et al.2011.Inter-seismic deformation field of the Ganzi-Yushu fault before the 2010 Yushu earthquake[J].Seismology and Geology,33(3):525-532.(in Chinese)
闻学泽,Allen C R,罗灼礼,等.1989.鲜水河全新世断裂带的分段性、几何特征及其地震构造意义[J].地震学报,11(4):362-372.
Wen X Z,Allen C R,Luo Z L,et al.1989.Segmentation,geometric features,and their seismotectonic implications for the Holocene Xianshuihe fault zone[J].Acta Seismologica Sinica,11(4):362-372.(in Chinese)
闻学泽,徐锡伟,郑荣章,等.2003.甘孜—玉树断裂带平均滑动速率与近代大地震破裂[J].中国科学:地球科学,33(S1):199-208.
Wen X Z,Xu X W,Zheng R Z,et al.2003.Average slip-rate and recent large earthquake ruptures along the Ganzi-Yushu fault[J].Scientia Sinica Terrae,33(S1):199-208.(in Chinese)
肖鹏.2022.甘孜—玉树断裂带当江段晚第四纪构造变形与地貌响应研究[D].三河:防灾科技学院.
Xiao P.2022.Study on late Quaternary tectonic deformation and geomorphic response of Dangjiang segment of Ganzi-Yushu fault zone in central Tibetan Plateau[D].Sanhe:Institute of Disaster Prevention.(in Chinese)
徐锡伟,闻学泽,郑荣章,等.2003.川滇地区活动块体最新构造变动样式及其动力来源[J].中国科学:地球科学,33(S1):151-162.
Xu X W,Wen X Z,Zheng R Z,et al.2003.The latest tectonic change pattern of the active block in Sichuan-Yunnan area and its power source[J].Scientia Sinica Terrae,33(S1):151-162.(in Chinese)
徐锡伟,张培震,闻学泽,等.2005.川西及其邻近地区活动构造基本特征与强震复发模型[J].地震地质,27(3):446-461.
Xu X W,Zhang P Z,Wen X Z,et al.2005.Features of active tectonics and recurrence behaviors of strong earthquakes in the Western Sichuan Province and its adjacent regions [J].Seismology and Geology,27(3):446-461.(in Chinese)
张培震,王敏,甘卫军,等.2003a.GPS观测的活动断裂滑动速率及其对现今大陆动力作用的制约[J].地学前缘,10(S1):81-92.
Zhang P Z,Wang M,Gan W J,et al.2003a.Slip rates along major active faults from GPS measurements and constraints on contemporary continental tectonics[J].Earth Science Frontiers,10(S1):81-92.(in Chinese)
张培震,邓起东,张国民,等.2003b.中国大陆强震活动与活动块体[J].中国科学:地球科学,33(S1):12-20.
Zhang P Z,Deng Q D,Zhang G M,et al.2003b.Seismic activity of strong earthquakes and active blocks in mainland China [J].Scientia Sinica Terrae,33(S1):12-20.(in Chinese)
周荣军,马声浩,蔡长星.1996.甘孜—玉树断裂带的晚第四纪活动特征[J].中国地震,12(4):250-260.
Zhou R J,Ma S H,Cai C X.1996.Late Quaternary active features of the Ganzi-Yushu fault zone[J].Earthquake Research in China,12(4):250-260.(in Chinese)
邹镇宇,江在森,武艳强,等.2018.走滑断层震间形变GPS观测站点布设的合理性分析[J].地震,38(1):26-34.
Zou Z Y,Jang Z S,Wu Y Q,et al.2018.GPS observation station layout for the analysis of interseismic deformation of strike-slip fault[J].Earthquake,38(1):26-34.(in Chinese)
Allen C R,Luo Z,Qian H,et al.1991.Field study of a highly active zone:The Xianshuihe fault of southwestern China[J].Geol Soc Am Bull,103(9):1178-1199.
England P,Molnar P.1997.The field of crustal velocity in Asia calculated from Quaternary rates of slip on faults[J].Geophys J Int,130(3):551-582.
Flesch L M,Haines A J,Holt W E.2001.Dynamics of the India-Eurasia collision zone[J].J Geophys Res,106(B8):16435-16460.
Gan W J,Zhang P Z,Shen Z K,et al.2007.Present-day crustal motion within the Tibetan Plateau inferred from GPS measurements[J].Journal of Geophysical Research Solid Earth,112(B8):1-14.
Jiang G Y,Xu X W,Chen G H,et al.2015.Geodetic imaging of potential seismogenic asperities on the Xianshuihe-Anninghe-Zemuhe fault system,Southwest China,with a new 3-D viscoelastic interseismic coupling model[J].Journal of Geophysical Research Solid Earth,120(3):1855-1873.
Replumaz A,Tapponnier P.2003.Reconstruction of the deformed collision zone between India and Asia by backward motion of lithospheric blocks[J].J Geophys Res,108(B6):2285.
Savage J C,Burford R O.1973.Geodetic determination of relative plate motion in central California[J].J Geophys Res,78(5):832-845.
Song S, Li Y,Hao M.2022.Active crustal deformation model of the Fen-Wei rift zone,North China:Integration of geologic,geodetic,and stress direction datasets[J].Frontiers in Earth Science,10:964800.
Tapponnier P,Xu Z Q,Roger F,et al.2001.Oblique stepwise rise and growth of the Tibet Plateau[J].Science,294(23):1671-1677.
Wang M,Shen Z K.2020.Present-day crustal deformation of continental China derived from GPS and its tectonic implications[J].Geophys Res:Solid Earth,125(2):e2019JB018774.
Xu R,Stamps D S.2016.Present-day kinematics of the Eastern Tibetan Plateau and Sichuan Basin:Implications for lower crustal rheology[J].Journal of Geophysical Research:Solid Earth,121(5):3846-3866.
Zhang P Z,Peter M,Xu X W.2007.Late Quaternary and present-day rates of slip along the Altyn Tagh fault,northern margin of the Tibetan Plateau[J].Tectonics,26:TC5010.
Zhang P Z.2013.A review on active tectonics and deep crustal processes of the Western Sichuan region,eastern margin of the Tibetan Plateau[J].Tectonophysics,584:7-22.

备注

引言

1 区域地质概况

2 数据与方法

3 结果分析

4 结论

期刊信息