南北地震带区域构造应力场反演
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摘要
利用区域应力张量阻尼方法,使用南北地震带及其邻近区域2009年1月—2017年8月466次M_L≥3.5地震的震源机制解,及1976年1月—2017年8月GCMT公布的259次M≥4.5地震的震源机制解,反演得到研究区1.0°×1.0°网格大小区域的构造应力场。应力场空间分布特征显示,南北地震带作为青藏高原的东边界,由于所处动力环境复杂,其内部最大主应力方向具有明显的空间差异性。这种差异主要表现为:南北地震带北段最大主应力方向为NE向;南北地震带中段及周边除龙门山断裂带NE段最大主应力为NW-NNW向外,其它地段最大主应力近EW向;南北地震带中南段最大主应力方向逐渐由近EW向到NW或NE向,再到近NS向。整体而言,南北地震带及邻近区域最大主应力方向由北到南发生了顺时针旋转。川滇菱形块体内部最大主应力方向为NNW向,应力方向转换带与块体边界基本一致,其东边界以东最大主应力方向为NW向,西边界以西为NNE向。从区域构造应力场的角度分析,难以将"南北地震带"作为一个统一的地震带应用于中长期地震预测的研究与实践中。
Using the regional stress tensor damping inversion method and focal mechanism data(466 M_L≥3.5 earthquakes focal mechanism solutions from January 2009 to August 2017 and259 M≥4.5 earthquakes focal mechanism solutions from January 1976 to August 2017 from the GCMT),we have obtained the distribution of the stress field by 1.0°×1.0° grid region in the North-South Seismic Belt and its adjacent regions. The spatial distributions of stress field show that,because of the complex dynamic environment,there are differences between the maximum principal stress direction inside the North-South Seismic Belt which is the east boundary of the Tibetan Plateau. The maximum principal stress direction in the northern segment of the North-South Seismic Belt is NE. In and surround the middle segment of the North-South Seismic Belt,the maximum principal stress direction is nearly EW except the NE segment of the Longmenshan fault zone whose direction is NW-NNW. The direction of the maximum principal stress in the middle and southern segments of the North-South Seismic Belt changes gradually,from nearly EW to NW/NE then to nearly NS. Overall,the maximum principal stress in the North-South Seismic Belt and its adjacent regions has a clockwise rotational pattern from north to south. Inside the Sichuan-Yunnan rhombic block the maximum principal stress is in NNW direction,while to the west of the west boundary the direction is NNE,to the east of the east boundary the direction is NW. The stress direction transition bands have well corresponded with the Sichuan-Yunnan rhombic block boundary. According to the analysis of regional tectonic stress field,it is difficult to apply the North-South Seismic Belt as a unified seismic belt to the medium and long-term earthquake prediction.
Using the regional stress tensor damping inversion method and focal mechanism data(466 M_L≥3.5 earthquakes focal mechanism solutions from January 2009 to August 2017 and259 M≥4.5 earthquakes focal mechanism solutions from January 1976 to August 2017 from the GCMT),we have obtained the distribution of the stress field by 1.0°×1.0° grid region in the North-South Seismic Belt and its adjacent regions. The spatial distributions of stress field show that,because of the complex dynamic environment,there are differences between the maximum principal stress direction inside the North-South Seismic Belt which is the east boundary of the Tibetan Plateau. The maximum principal stress direction in the northern segment of the North-South Seismic Belt is NE. In and surround the middle segment of the North-South Seismic Belt,the maximum principal stress direction is nearly EW except the NE segment of the Longmenshan fault zone whose direction is NW-NNW. The direction of the maximum principal stress in the middle and southern segments of the North-South Seismic Belt changes gradually,from nearly EW to NW/NE then to nearly NS. Overall,the maximum principal stress in the North-South Seismic Belt and its adjacent regions has a clockwise rotational pattern from north to south. Inside the Sichuan-Yunnan rhombic block the maximum principal stress is in NNW direction,while to the west of the west boundary the direction is NNE,to the east of the east boundary the direction is NW. The stress direction transition bands have well corresponded with the Sichuan-Yunnan rhombic block boundary. According to the analysis of regional tectonic stress field,it is difficult to apply the North-South Seismic Belt as a unified seismic belt to the medium and long-term earthquake prediction.
引文
陈章立,李志雄. 2013.地震预报的科学原理与逻辑思维[M].北京:地震出版社:51–61.Chen Z L,Li Z X. 2013. Scientific Principles and Logical Thought in Earthquake Prediction[M]. Beijing:Seismological Press:51 –61(in Chinese).
崔效锋,谢富仁. 1999.利用震源机制解对中国西南及邻区进行应力分区的初步研究[J].地震学报,21(5):513–522.Cui X F,Xie F R. 1999. Preliminary study of stress division in southwestern China and adjacent regions[J]. Acta Seismologica Sinica,21(5):513–522(in Chinese).
郝平,吕晓健,田勤俭,傅征祥,陈丹. 2012.中国西部及邻区活动地块边界带现代构造应力场[J].地震学报, 34(4):439 –450.Hao P,LüX J,Tian Q J,Fu Z X,Chen D. 2012. Contemporary tectonic stress field on boundaries of active tectonic blocks in and around western China[J]. Acta Seismologica Sinica,34(4):439–450(in Chinese).
马杏垣. 1989.中国岩石圈动力学地图集[M].北京:中国地图出版社:2–68.Ma X Y. 1989. Lithospheric Dynamics Atlas of China[M]. Beijing:China Cartographic Publishing House:2–68(in Chinese).
王椿镛,杨文采,吴建平,丁志峰. 2015.南北构造带岩石圈结构与地震的研究[J].地球物理学报,58(11):3867–3901.Wang C Y,Yang W C,Wu J P,Ding Z F. 2015. Study on the lithospheric structure and earthquakes in North-South Tectonic Belt[J]. Chinese Journal of Geophysics,58(11):3867–3901(in Chinese).
王晓山,吕坚,谢祖军,龙锋,赵小艳,郑勇. 2015.南北地震带震源机制解与构造应力场特征[J].地球物理学报,58 (11):4149–4162.Wang X S,LüJ,Xie Z J,Long F,Zhao X Y,Zheng Y. 2015. Focal mechanisms and tectonic stress field in the North-South Seismic Belt of China[J]. Chinese Journal of Geophysics,58(11):4149–4162(in Chinese).
王阎昭,王恩宁,沈正康,王敏,甘卫军,乔学军,孟国杰,李铁明,陶玮,杨永林,程佳,李鹏. 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:D辑,38(5):582–597.Wang Y Z,Wang E N,Shen Z K,Wang M,Gan W J,Qiao X J,Meng G J,Li T M,Tao W,Yang Y L,Cheng J,Li P. 2008.GPS constrained inversion of present-day slip rates along major faults of the Sichuan-Yunnan region,China[J]. Science in China:Series D,38(5):582–597(in Chinese).
谢富仁,崔效锋,赵建涛,陈群策,李宏. 2004.中国大陆及邻区现代构造应力场分区[J].地球物理学报, 47(4):654 –662.Xie F R,Cui X F,Zhao J T,Chen Q C,Li H. 2004. Regional division of the recent tectonic stress field in China and adjacent areas[J]. Chinese Journal of Geophysics,47(4):654–662(in Chinese).
徐纪人,赵志新,石川有三. 2008.中国大陆地壳应力场与构造运动区域特征研究[J].地球物理学报,51(3):770–781.Xu J R,Zhao Z X,Ishikawa Y. 2008. Regional characteristics of crustal stress field and tectonic motions in and around Chinese mainland[J]. Chinese Journal of Geophysics,51(3):770–781(in Chinese).
许忠淮,汪素云,黄雨蕊,高阿甲,金小锋,常向东. 1987.由多个小震推断的青甘和川滇地区地壳应力场的方向特征[J].地球物理学报,30(5):476–486.Xu Z H,Wang S Y,Huang Y R,Gao A J,Jin X F,Chang X D. 1987. Directions of mean stress axes in southwestern China deduced from microearthquake data[J]. Chinese Journal of. Geophysics,30(5):476–486(in Chinese).
许忠淮,汪素云,黄雨蕊,高阿甲. 1989.由大量地震的资料推断我国大陆构造应力场[J].地球物理学报, 32(6):636 –647.Xu Z H,Wang S Y,Huang Y R,Gao A J. 1989. The tectonic stress field of Chinese continent deduced from a great number of earthquakes[J]. Chinese Journal of Geophysics,32(6):636–647(in Chinese).
鄢家全,时振梁,汪素云,环文林. 1979.中国及邻区现代构造应力场的区域特征[J].地震学报,1(1):9–24.Yan J Q,Shi Z L,Wang S Y,Huan W L. 1979. Some features of the recent tectonic stress field of China and environs[J]. Acta Seismologica Sinica,1(1):9–24(in Chinese).
张文佑. 1959.中国大地构造纲要[M].北京:科学出版社:1–320.Zhang W Y. 1959. Outline of Chinese Geotectonics[M]. Beijing:Science Press:1–320(in Chinese).
郑秀芬,欧阳彪,张东宁,姚志祥,梁建宏,郑洁. 2009.“国家数字测震台网数据备份中心”技术系统建设及其对汶川大地震研究的数据支撑[J].地球物理学报,52(5):1412–1417.Zheng X F,Ouyang B,Zhang D N,Yao Z X,Liang J H,Zheng J. 2009. Technical system construction of Data Backup Centre for China Seismograph Network and the data support to researches on the Wenchuan earthquake[J]. Chinese Journal of Geophysics,52(5):1412–1417(in Chinese).
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(B11310):1–11.
Luo J,Zhao C P,LüJ,Zhou L Q,Zheng S H. 2016. Characteristics of focal mechanisms and the stress field in the southeastern margin of the Tibetan Plateau[J]. Pure Appl Geophys,173:2687–2710.
Michael A J. 1984. Determination of stress from slip data:Faults and folds[J]. J Geophys Res,89(B13):11517–11526.
Wan Y G. 2010. Contemporary tectonic stress field in China[J]. Earthquake Science,23(4):377–386.
Wang Q,Zhang P Z,Freymueller J T,Bilham R,Larson K M,Lai X A,You X Z,Niu Z J,Wu J C,Li Y X,Liu J N,Yang Z Q,Chen Q Z. 2001. Present-day crustal deformation in China constrained by Global Positioning System measurements[J].Science,294(5542):574–577.
Wang Q C,Chen Z L,Zheng S H. 2009. Spatial segmentation characteristic of focal mechanism of aftershock of Wenchuan earthquake[J]. Chinese Science Bulletin,54(6):2263–2270.
Xu Z G,Huang Z C,Wang L S,Xu M J,Ding Z F,Wang P,Mi N,Yu D Y,Li H. 2016. Crustal stress field in Yunnan:Implication for crust-mantle coupling[J]. Earthquake Science,29(2):105–115.
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.
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 Seism Soc Am,103(4):2498–2507.
Zhao L S,Helmberger D V. 1994. Source estimation from broadband regional seismograms[J]. Bull Seism Soc Am,84(1):91–104.
Zheng Y,Ma H S,LüJ,Ni S D,Li Y C,Wei S J. 2009. Source mechanism of strong aftershocks(MS≥5.6)of the 2008-05-12Wenchuan earthquake and the implication for seismotectonics[J]. Science China Earth Science,52(6):739–753.
Zheng Y,Ni S D,Xie Z J,LüJ,Ma H S,Sommerville P. 2010. Strong aftershocks in the northern segment of the Wenchuan earthquake rupture zone and their seismotectonic implications[J]. Earth Planet Space,62:1–6.
Zhu L P,Helmberger D V. 1996. Advancement in source estimation techniques using broadband regional seismograms[J]. Bull Seism Soc Am,86(5):1634–1641.
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.
崔效锋,谢富仁. 1999.利用震源机制解对中国西南及邻区进行应力分区的初步研究[J].地震学报,21(5):513–522.Cui X F,Xie F R. 1999. Preliminary study of stress division in southwestern China and adjacent regions[J]. Acta Seismologica Sinica,21(5):513–522(in Chinese).
郝平,吕晓健,田勤俭,傅征祥,陈丹. 2012.中国西部及邻区活动地块边界带现代构造应力场[J].地震学报, 34(4):439 –450.Hao P,LüX J,Tian Q J,Fu Z X,Chen D. 2012. Contemporary tectonic stress field on boundaries of active tectonic blocks in and around western China[J]. Acta Seismologica Sinica,34(4):439–450(in Chinese).
马杏垣. 1989.中国岩石圈动力学地图集[M].北京:中国地图出版社:2–68.Ma X Y. 1989. Lithospheric Dynamics Atlas of China[M]. Beijing:China Cartographic Publishing House:2–68(in Chinese).
王椿镛,杨文采,吴建平,丁志峰. 2015.南北构造带岩石圈结构与地震的研究[J].地球物理学报,58(11):3867–3901.Wang C Y,Yang W C,Wu J P,Ding Z F. 2015. Study on the lithospheric structure and earthquakes in North-South Tectonic Belt[J]. Chinese Journal of Geophysics,58(11):3867–3901(in Chinese).
王晓山,吕坚,谢祖军,龙锋,赵小艳,郑勇. 2015.南北地震带震源机制解与构造应力场特征[J].地球物理学报,58 (11):4149–4162.Wang X S,LüJ,Xie Z J,Long F,Zhao X Y,Zheng Y. 2015. Focal mechanisms and tectonic stress field in the North-South Seismic Belt of China[J]. Chinese Journal of Geophysics,58(11):4149–4162(in Chinese).
王阎昭,王恩宁,沈正康,王敏,甘卫军,乔学军,孟国杰,李铁明,陶玮,杨永林,程佳,李鹏. 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:D辑,38(5):582–597.Wang Y Z,Wang E N,Shen Z K,Wang M,Gan W J,Qiao X J,Meng G J,Li T M,Tao W,Yang Y L,Cheng J,Li P. 2008.GPS constrained inversion of present-day slip rates along major faults of the Sichuan-Yunnan region,China[J]. Science in China:Series D,38(5):582–597(in Chinese).
谢富仁,崔效锋,赵建涛,陈群策,李宏. 2004.中国大陆及邻区现代构造应力场分区[J].地球物理学报, 47(4):654 –662.Xie F R,Cui X F,Zhao J T,Chen Q C,Li H. 2004. Regional division of the recent tectonic stress field in China and adjacent areas[J]. Chinese Journal of Geophysics,47(4):654–662(in Chinese).
徐纪人,赵志新,石川有三. 2008.中国大陆地壳应力场与构造运动区域特征研究[J].地球物理学报,51(3):770–781.Xu J R,Zhao Z X,Ishikawa Y. 2008. Regional characteristics of crustal stress field and tectonic motions in and around Chinese mainland[J]. Chinese Journal of Geophysics,51(3):770–781(in Chinese).
许忠淮,汪素云,黄雨蕊,高阿甲,金小锋,常向东. 1987.由多个小震推断的青甘和川滇地区地壳应力场的方向特征[J].地球物理学报,30(5):476–486.Xu Z H,Wang S Y,Huang Y R,Gao A J,Jin X F,Chang X D. 1987. Directions of mean stress axes in southwestern China deduced from microearthquake data[J]. Chinese Journal of. Geophysics,30(5):476–486(in Chinese).
许忠淮,汪素云,黄雨蕊,高阿甲. 1989.由大量地震的资料推断我国大陆构造应力场[J].地球物理学报, 32(6):636 –647.Xu Z H,Wang S Y,Huang Y R,Gao A J. 1989. The tectonic stress field of Chinese continent deduced from a great number of earthquakes[J]. Chinese Journal of Geophysics,32(6):636–647(in Chinese).
鄢家全,时振梁,汪素云,环文林. 1979.中国及邻区现代构造应力场的区域特征[J].地震学报,1(1):9–24.Yan J Q,Shi Z L,Wang S Y,Huan W L. 1979. Some features of the recent tectonic stress field of China and environs[J]. Acta Seismologica Sinica,1(1):9–24(in Chinese).
张文佑. 1959.中国大地构造纲要[M].北京:科学出版社:1–320.Zhang W Y. 1959. Outline of Chinese Geotectonics[M]. Beijing:Science Press:1–320(in Chinese).
郑秀芬,欧阳彪,张东宁,姚志祥,梁建宏,郑洁. 2009.“国家数字测震台网数据备份中心”技术系统建设及其对汶川大地震研究的数据支撑[J].地球物理学报,52(5):1412–1417.Zheng X F,Ouyang B,Zhang D N,Yao Z X,Liang J H,Zheng J. 2009. Technical system construction of Data Backup Centre for China Seismograph Network and the data support to researches on the Wenchuan earthquake[J]. Chinese Journal of Geophysics,52(5):1412–1417(in Chinese).
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(B11310):1–11.
Luo J,Zhao C P,LüJ,Zhou L Q,Zheng S H. 2016. Characteristics of focal mechanisms and the stress field in the southeastern margin of the Tibetan Plateau[J]. Pure Appl Geophys,173:2687–2710.
Michael A J. 1984. Determination of stress from slip data:Faults and folds[J]. J Geophys Res,89(B13):11517–11526.
Wan Y G. 2010. Contemporary tectonic stress field in China[J]. Earthquake Science,23(4):377–386.
Wang Q,Zhang P Z,Freymueller J T,Bilham R,Larson K M,Lai X A,You X Z,Niu Z J,Wu J C,Li Y X,Liu J N,Yang Z Q,Chen Q Z. 2001. Present-day crustal deformation in China constrained by Global Positioning System measurements[J].Science,294(5542):574–577.
Wang Q C,Chen Z L,Zheng S H. 2009. Spatial segmentation characteristic of focal mechanism of aftershock of Wenchuan earthquake[J]. Chinese Science Bulletin,54(6):2263–2270.
Xu Z G,Huang Z C,Wang L S,Xu M J,Ding Z F,Wang P,Mi N,Yu D Y,Li H. 2016. Crustal stress field in Yunnan:Implication for crust-mantle coupling[J]. Earthquake Science,29(2):105–115.
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.
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 Seism Soc Am,103(4):2498–2507.
Zhao L S,Helmberger D V. 1994. Source estimation from broadband regional seismograms[J]. Bull Seism Soc Am,84(1):91–104.
Zheng Y,Ma H S,LüJ,Ni S D,Li Y C,Wei S J. 2009. Source mechanism of strong aftershocks(MS≥5.6)of the 2008-05-12Wenchuan earthquake and the implication for seismotectonics[J]. Science China Earth Science,52(6):739–753.
Zheng Y,Ni S D,Xie Z J,LüJ,Ma H S,Sommerville P. 2010. Strong aftershocks in the northern segment of the Wenchuan earthquake rupture zone and their seismotectonic implications[J]. Earth Planet Space,62:1–6.
Zhu L P,Helmberger D V. 1996. Advancement in source estimation techniques using broadband regional seismograms[J]. Bull Seism Soc Am,86(5):1634–1641.
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.