北天山中段微震活动检测及其活动性和孕震构造分析
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摘要
北天山地震带地处中国大陆强震高发区,孕震构造复杂,近年来陆续发生了2016年呼图壁M_S6.2地震和2017年精河M_S6.6地震。由于测震台网相对比较稀疏,该区域微震监测能力较弱。本文主要采用波形模板扫描法对北天山中段(43.5°N～44.5°N; 85°E～87.5°E)进行微震事件检测,并反演精细的一维速度结构,重新定位地震;深入分析该区域的地震活动性和孕震构造特征。经过微震检测,得到该地区2014年1月至2018年9月期间57902个地震事件,是原地震目录的10倍,完备震级从1.2降至0.5。结果显示,北天山中段地震十分活跃,主要分布在北天山山前霍尔果斯—玛纳斯—吐谷鲁背斜带南翼的浅部和南玛纳斯—齐古背斜带深部,呼图壁地震震后地震活动性有增强的趋势。研究期间沿背斜构造带走向地震分布不均,霍尔果斯—玛纳斯—吐谷鲁背斜带西段地震活动多于东段,南玛纳斯—齐古背斜带东段地震活动显著强于西段。经过重定位,发现研究区的地震事件主要发生在褶皱内部的"盲断层"上,这些隐伏断裂与区域活动断裂和背斜构造共同组成的断层系孕育了北天山山前活跃的地震活动,并可能成为未来强震的发震构造。
The North Tianshan Seismic Belt in China has complex seismogenic structures with high risk of strong earthquake. The 2016 Hutubi M_S6.2 earthquake and the 2017 Jinghe M_S6.6 earthquake occurred successively in recent years. However, because the seismic network of North Tianshan is relatively sparse, the ability to monitor micro-seismicity in this area is weak. In this paper, we detected microseismic events from continuous waveforms with the waveform matched filter technique in the middle section of the North Tianshan Mountains(about 43.5°N～44.5°N, 85°E～87.5°E), relocated them with revised velocity structure, and then analyzed the characteristics of seismicity and seismogenic structure in this area. The scan detected 57 902 events in the study area from January 2014 to September 2018, about 10 times earthquake events in CENC(China Earthquake Networks Center) catalog, and the complete magnitude decreased from 1.2 to 0.5. The results show that there are obvious swarm activities in the study area, which mainly occurred after the Shawan and Hutubi earthquakes and distributed in the shallow southern flank of the Huoerguosi-Manasi-Tugulu anticlinal belt and deep South Manasi-Qigu anticlinal belt. Earthquakes along the strike of anticlinal tectonic belt are unevenly distributed. Earthquakes in the western Huoereguosi-Manasi-Tugulu anticlinal belt are more than that in the eastern part. But the earthquake magnitude in eastern South Manasi-Qigu anticlinal belt is significantly larger than that in the western part. After relocation, we found that the seismic events in the study area mainly occurred on the "blind faults" within the folds. The regional large active faults and concealed faults in anticlinal structures gave birth to active seismicity in the piedmont of the North Tianshan Mountains, and would become the sources of future strong earthquakes.
The North Tianshan Seismic Belt in China has complex seismogenic structures with high risk of strong earthquake. The 2016 Hutubi M_S6.2 earthquake and the 2017 Jinghe M_S6.6 earthquake occurred successively in recent years. However, because the seismic network of North Tianshan is relatively sparse, the ability to monitor micro-seismicity in this area is weak. In this paper, we detected microseismic events from continuous waveforms with the waveform matched filter technique in the middle section of the North Tianshan Mountains(about 43.5°N～44.5°N, 85°E～87.5°E), relocated them with revised velocity structure, and then analyzed the characteristics of seismicity and seismogenic structure in this area. The scan detected 57 902 events in the study area from January 2014 to September 2018, about 10 times earthquake events in CENC(China Earthquake Networks Center) catalog, and the complete magnitude decreased from 1.2 to 0.5. The results show that there are obvious swarm activities in the study area, which mainly occurred after the Shawan and Hutubi earthquakes and distributed in the shallow southern flank of the Huoerguosi-Manasi-Tugulu anticlinal belt and deep South Manasi-Qigu anticlinal belt. Earthquakes along the strike of anticlinal tectonic belt are unevenly distributed. Earthquakes in the western Huoereguosi-Manasi-Tugulu anticlinal belt are more than that in the eastern part. But the earthquake magnitude in eastern South Manasi-Qigu anticlinal belt is significantly larger than that in the western part. After relocation, we found that the seismic events in the study area mainly occurred on the "blind faults" within the folds. The regional large active faults and concealed faults in anticlinal structures gave birth to active seismicity in the piedmont of the North Tianshan Mountains, and would become the sources of future strong earthquakes.
引文
[1] Guan S W,Stockmeyer J M,Shaw J H,et al.Structural inversion,imbricate wedging,and out-of-sequence thrusting in the southern Junggar fold-and-thrust belt,northern Tian Shan,China[J].American Association of Petroleum Geologists Bulletin,2016 ,100 (9):1443-1468.
[2] Yin A.Cenozoic tectonic evolution of Asia:A preliminary synthesis[J].Tectonophysics,2010,488(1-4):293-325.
[3] Avouac J P,Tapponnier P,Bai M,et al.Active thrusting and folding along the northern Tien Shan and Late Cenozoic rotation of the Tarim relative to Dzungaria and Kazakhstan[J].Journal of Geophysical Research:Solid Earth,1993,98(B4):6755-6804.
[4] Molnar P,Brown E T,Burchfiel B C,et al.Quaternary Climate Change and the Formation of River Terraces across Growing Anticlines on the North Flank of the Tien Shan,China[J].The Journal of Geology,1994,102(5):583-602.
[5] 漆家福,陈书平,杨桥,等.准噶尔—北天山盆山过渡带构造基本特征[J].石油与天然气地质,2008,29(2):252-260.
[6] 陈立春.北天山乌鲁木齐转换区构造系晚第四纪活动性[D].北京:中国地震局地质研究所,2011.
[7] 汪新伟,汪新文,刘剑平,等.准噶尔盆地南缘褶皱-逆冲断层带分析[J].地学前缘,2005,12(4):411-421.
[8] Stockmeyer J M ,Shaw J H,Brown N D,et al.Active thrust sheet deformation over multiple rupture cycles:A quantitative basisfor relating terrace folds to fault slip rates[J].Bulletin of the Geological Society of America,2017,129(9-10):1337-1356.
[9] Lu R,He D,Xu X,et al.Seismotectonics of the 2016 M6.2 Hutubi earthquake:Implications for the 1906 M7.7 Manas earthquake in the northern Tian Shan belt,China[J].Seismological Research Letters,2017,89 (1):13-21.
[10] 张培震,邓起东,徐锡伟,等.盲断裂、 褶皱地震与新疆1906年玛纳斯地震[J].地震地质,1994,16(3):193-204.
[11] Yang Y H,Hu J C,Chen Q,et al.A blind thrust and overlying folding earthquake of the 2016 MW6.0 Hutubi earthquake in the northern Tien Shan fold-and-thrust belts,China[J].Bulletin of the Seismological Society of America,2019,109(2):770-779.
[12] 傅征祥.中国大陆地震活动性力学研究[M].北京:地震出版社,1997.
[13] Wang W,Meng X,Peng Z,et al.Increasing background seismicity and dynamic triggering behaviors with nearby mining activities around Fangshan Pluton in Beijing,China[J].Journal of Geophysical Research Solid Earth,2015,120(8):5624-5638.
[14] Peng Z,Zhao P.Migration of early aftershocks following the 2004 Parkfield earthquake[J].Nature Geoscience,2009,2(12):877-881.
[15] Meng X,Yang H F,Peng Z.Foreshocks,b value map,and aftershock triggering for the 2011 MW5.7 Virginia earthquake[J].Journal of Geophysical Research:Solid Earth,2018,123(6):5082-5098.
[16] Peng Z,Vidale J E,Houston H.Anomalous early aftershock decay rate of the 2004 MW6.0 Parkfield,California,earthquake[J].Geophysical Research Letters,2006,33(17):L17307.
[17] 张淼.地震定位和检测[D].合肥:中国科学技术大学,2015.
[18] Shelly D R,Beroza G C,Ide S.Non-volcanic tremor and low-frequency earthquake swarms[J].Nature,2007,446(7133):305-307.
[19] 曾融生,孙为国,毛桐恩,等.中国大陆莫霍界面深度图[J].地震学报,1995,17(3):322-327.
[20] 李秋生,卢德源,高锐,等.新疆地学断面(泉水沟—独山子)深地震测深成果综合研究[J].地球学报,2001,22(6):534-540.
[21] Zhao J M,Li G D,Lu Z X,et al.Lithospheric structure and dynamic processes of the Tianshan orogenic belt and the Junggar basin[J].Tectonophysics,2003,376(3-4):199-239.
[22] 王有学,韩果花,姜枚,等.阿尔泰—阿尔金地学断面地壳结构[J].地球物理报,2004,47(2):240-249.
[23] 张先康,曲国胜,赵金仁.准噶尔盆地深部构造人工地震探测[J].新疆石油质,2008,29(6):675-679.
[24] 陈向军,上官文明,宋秀青.新疆地区一维地壳速度模型研究[J].地震工程学报,2018,40(2):294-304.
[25] 李昱,刘启元,陈九辉,等.天山地壳上地幔的 S 波速度结构[J].中国科学D辑:地球科学,2007,37(3):344-352.
[26] 孔祥艳,陈向军,刘建明,等.2016年12月8日呼图壁MS6.2地震余震序列精定位研究[J].内陆地震,2017,31(3):237-241.
[27] 刘建明,王琼,李金,等.2016年12月8日呼图壁MS6.2地震序列重定位与发震构造[J].地震地质,2018,40(3):566-578.
[28] Kissling E,Kradolfer U,Maurer H.VELEST User′s Guide-Short Introduction,Technical Rept.,Institute of Geophysics,ETH Zürich,Zürich,Switzerland,1995.
[29] 高家乙,李永华,徐小明,等.云南地区地壳速度结构和地震活动性研究[J].地球物理学进展,2016,31(2):508-516.
[30] Waldhauser F,Ellsworth W L.A double-difference earthquake location algorithm:method and application to the Northern Hayward Fault,California[J].Bulletin of the Seismological Society of America,2000,90(6):1353-1368.
[31] 王清东.利用双差定位法研究云南地震分布的活动构造意义[D].武汉:武汉大学,2015.
[32] 唐明帅,王海涛,李艳永,等.2014年新疆于田MS7.3地震序列重定位及其发震构造初步研究[J].地球物理学报,2016,59(6):2126-2137.
[33] 房立华,吴建平,王未来,等.2014年新疆于田MS7.3级地震序列重定位[J].地球物理学报,2015,58(3):802-808.
[34] Gang L,Qiao X J,Xiong W,et al.Source models for the 2016 MW6.0 Hutubi earthquake,Xinjiang,China:A possible reverse event[J].Geodesy and Geodynamics,2017,8(5):311-318.
[35] 杨文,程佳,姚琪,等.2016 年新疆呼图壁6.2级地震发震构造[J].地震地质,2018,40(5):1100-1113.
[36] 王娟娟,姚华建,王伟涛,等.基于背景噪声成像方法的新疆呼图壁储气库地区近地表速度结构研究[J].地球物理学报,2018,61(11):120-131.
[37] 邓起东,冯先岳,张培震,等.乌鲁木齐山前坳陷逆断裂-褶皱带及其形成机制[J].地学前缘,1999,6(4):191-201.
[38] Tang L L,Lu Z,Zhang M,et al.Seismicity induced by simultaneous abrupt changes of injection rate and well pressure in Hutubi Gas Field[J].Journal of Geophysical Research:Solid Earth,2018,123 (7):5929-5944.
[39] Stein R S,Yeats R S.Hidden Earthquake[J].Scientific American,1989,260(6):48-57.
[40] Stein R S,King G C P.Seismic Potential Revealed by Surface Folding:1983 Coalinga,California,Earthquake[J].Science,1984,224(4651):869-872.
[41] 王椿镛,楼海,魏修成,等.天山北缘的地壳结构和1906年玛纳斯地震的地震构造[J].地震学报,2001,23(5):460-470.
[42] Stockmeyer J M,Shaw J H,Guan S W.Seismic hazards of multisegment thrust-fault ruptures:Insights from the 1906 MW7.4—8.2 Manas,China,Earthquake[J].Seismological Research Letters,2014,85(4):801-808.
[43] 管树巍,张朝军,何登发,等.前陆冲断带复杂构造解析与建模——以准噶尔盆地南缘第一排背斜带为例[J].地质学报,2006,80(8):1131-1140.
[2] Yin A.Cenozoic tectonic evolution of Asia:A preliminary synthesis[J].Tectonophysics,2010,488(1-4):293-325.
[3] Avouac J P,Tapponnier P,Bai M,et al.Active thrusting and folding along the northern Tien Shan and Late Cenozoic rotation of the Tarim relative to Dzungaria and Kazakhstan[J].Journal of Geophysical Research:Solid Earth,1993,98(B4):6755-6804.
[4] Molnar P,Brown E T,Burchfiel B C,et al.Quaternary Climate Change and the Formation of River Terraces across Growing Anticlines on the North Flank of the Tien Shan,China[J].The Journal of Geology,1994,102(5):583-602.
[5] 漆家福,陈书平,杨桥,等.准噶尔—北天山盆山过渡带构造基本特征[J].石油与天然气地质,2008,29(2):252-260.
[6] 陈立春.北天山乌鲁木齐转换区构造系晚第四纪活动性[D].北京:中国地震局地质研究所,2011.
[7] 汪新伟,汪新文,刘剑平,等.准噶尔盆地南缘褶皱-逆冲断层带分析[J].地学前缘,2005,12(4):411-421.
[8] Stockmeyer J M ,Shaw J H,Brown N D,et al.Active thrust sheet deformation over multiple rupture cycles:A quantitative basisfor relating terrace folds to fault slip rates[J].Bulletin of the Geological Society of America,2017,129(9-10):1337-1356.
[9] Lu R,He D,Xu X,et al.Seismotectonics of the 2016 M6.2 Hutubi earthquake:Implications for the 1906 M7.7 Manas earthquake in the northern Tian Shan belt,China[J].Seismological Research Letters,2017,89 (1):13-21.
[10] 张培震,邓起东,徐锡伟,等.盲断裂、 褶皱地震与新疆1906年玛纳斯地震[J].地震地质,1994,16(3):193-204.
[11] Yang Y H,Hu J C,Chen Q,et al.A blind thrust and overlying folding earthquake of the 2016 MW6.0 Hutubi earthquake in the northern Tien Shan fold-and-thrust belts,China[J].Bulletin of the Seismological Society of America,2019,109(2):770-779.
[12] 傅征祥.中国大陆地震活动性力学研究[M].北京:地震出版社,1997.
[13] Wang W,Meng X,Peng Z,et al.Increasing background seismicity and dynamic triggering behaviors with nearby mining activities around Fangshan Pluton in Beijing,China[J].Journal of Geophysical Research Solid Earth,2015,120(8):5624-5638.
[14] Peng Z,Zhao P.Migration of early aftershocks following the 2004 Parkfield earthquake[J].Nature Geoscience,2009,2(12):877-881.
[15] Meng X,Yang H F,Peng Z.Foreshocks,b value map,and aftershock triggering for the 2011 MW5.7 Virginia earthquake[J].Journal of Geophysical Research:Solid Earth,2018,123(6):5082-5098.
[16] Peng Z,Vidale J E,Houston H.Anomalous early aftershock decay rate of the 2004 MW6.0 Parkfield,California,earthquake[J].Geophysical Research Letters,2006,33(17):L17307.
[17] 张淼.地震定位和检测[D].合肥:中国科学技术大学,2015.
[18] Shelly D R,Beroza G C,Ide S.Non-volcanic tremor and low-frequency earthquake swarms[J].Nature,2007,446(7133):305-307.
[19] 曾融生,孙为国,毛桐恩,等.中国大陆莫霍界面深度图[J].地震学报,1995,17(3):322-327.
[20] 李秋生,卢德源,高锐,等.新疆地学断面(泉水沟—独山子)深地震测深成果综合研究[J].地球学报,2001,22(6):534-540.
[21] Zhao J M,Li G D,Lu Z X,et al.Lithospheric structure and dynamic processes of the Tianshan orogenic belt and the Junggar basin[J].Tectonophysics,2003,376(3-4):199-239.
[22] 王有学,韩果花,姜枚,等.阿尔泰—阿尔金地学断面地壳结构[J].地球物理报,2004,47(2):240-249.
[23] 张先康,曲国胜,赵金仁.准噶尔盆地深部构造人工地震探测[J].新疆石油质,2008,29(6):675-679.
[24] 陈向军,上官文明,宋秀青.新疆地区一维地壳速度模型研究[J].地震工程学报,2018,40(2):294-304.
[25] 李昱,刘启元,陈九辉,等.天山地壳上地幔的 S 波速度结构[J].中国科学D辑:地球科学,2007,37(3):344-352.
[26] 孔祥艳,陈向军,刘建明,等.2016年12月8日呼图壁MS6.2地震余震序列精定位研究[J].内陆地震,2017,31(3):237-241.
[27] 刘建明,王琼,李金,等.2016年12月8日呼图壁MS6.2地震序列重定位与发震构造[J].地震地质,2018,40(3):566-578.
[28] Kissling E,Kradolfer U,Maurer H.VELEST User′s Guide-Short Introduction,Technical Rept.,Institute of Geophysics,ETH Zürich,Zürich,Switzerland,1995.
[29] 高家乙,李永华,徐小明,等.云南地区地壳速度结构和地震活动性研究[J].地球物理学进展,2016,31(2):508-516.
[30] Waldhauser F,Ellsworth W L.A double-difference earthquake location algorithm:method and application to the Northern Hayward Fault,California[J].Bulletin of the Seismological Society of America,2000,90(6):1353-1368.
[31] 王清东.利用双差定位法研究云南地震分布的活动构造意义[D].武汉:武汉大学,2015.
[32] 唐明帅,王海涛,李艳永,等.2014年新疆于田MS7.3地震序列重定位及其发震构造初步研究[J].地球物理学报,2016,59(6):2126-2137.
[33] 房立华,吴建平,王未来,等.2014年新疆于田MS7.3级地震序列重定位[J].地球物理学报,2015,58(3):802-808.
[34] Gang L,Qiao X J,Xiong W,et al.Source models for the 2016 MW6.0 Hutubi earthquake,Xinjiang,China:A possible reverse event[J].Geodesy and Geodynamics,2017,8(5):311-318.
[35] 杨文,程佳,姚琪,等.2016 年新疆呼图壁6.2级地震发震构造[J].地震地质,2018,40(5):1100-1113.
[36] 王娟娟,姚华建,王伟涛,等.基于背景噪声成像方法的新疆呼图壁储气库地区近地表速度结构研究[J].地球物理学报,2018,61(11):120-131.
[37] 邓起东,冯先岳,张培震,等.乌鲁木齐山前坳陷逆断裂-褶皱带及其形成机制[J].地学前缘,1999,6(4):191-201.
[38] Tang L L,Lu Z,Zhang M,et al.Seismicity induced by simultaneous abrupt changes of injection rate and well pressure in Hutubi Gas Field[J].Journal of Geophysical Research:Solid Earth,2018,123 (7):5929-5944.
[39] Stein R S,Yeats R S.Hidden Earthquake[J].Scientific American,1989,260(6):48-57.
[40] Stein R S,King G C P.Seismic Potential Revealed by Surface Folding:1983 Coalinga,California,Earthquake[J].Science,1984,224(4651):869-872.
[41] 王椿镛,楼海,魏修成,等.天山北缘的地壳结构和1906年玛纳斯地震的地震构造[J].地震学报,2001,23(5):460-470.
[42] Stockmeyer J M,Shaw J H,Guan S W.Seismic hazards of multisegment thrust-fault ruptures:Insights from the 1906 MW7.4—8.2 Manas,China,Earthquake[J].Seismological Research Letters,2014,85(4):801-808.
[43] 管树巍,张朝军,何登发,等.前陆冲断带复杂构造解析与建模——以准噶尔盆地南缘第一排背斜带为例[J].地质学报,2006,80(8):1131-1140.