川西北跨度23a的原地应力实测数据特征及其地壳动力学意义分析
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摘要
研究区位于龙门山断裂带北段的中央断裂带和前山断裂带之间,该区地质结构主要为准原地体系和逆冲推覆体系,岩性以志留系下统的泥岩、粉砂泥岩分布最广,遍及全区。为了满足该区一工程建设的需要,在研究范围内开展了4个钻孔的水压致裂原地应力测量工作,测试时间跨度达23 a。测试数据显示,虽然测试时间跨度达23 a,但是原地应力状态基本没有变化,研究区最大水平主应力方向的优势方向为N24.4°W,最大、最小水平主应力随深度线性增加的梯度分别为0.036和0.025。基于实测数据计算的特征参数kH max,kh min,m和R在23 a内没有变化。该区域位于龙门山断裂带中央断裂的下盘,为被动盘,断层活动性和地震活动性都极其微弱,这种特殊的区域地壳动力学条件决定了研究区稳定的区域应力场特征。通过与以往研究成果的对比分析可知,m较好地反映了该区域地壳的应力积累能力,即从应力积累的角度反映了区域断层的强度,这一研究与以往研究成果十分吻合。在未来的研究中,或许可以利用实测应力资料计算的m值,再结合区域断层和地震活动性的比较分析来评价特定区域的地震危险性。
The research area,in Lizhou district,Guanyuan City in the northwest Sichuan Basin,is located between the central faults and front faults of north section of Longmenshan fault belt.The major geological structural units in the research area are semi-platform unit and thrust nappe unit.The lithology is mainly mudstone and silt mudstone formed during the lower Silurian era,which are present almost all over the research area.In order to meet the requirements of one engineering establishment,the in-situ stress measurements by hydraulic fracturing method in four boreholes were accomplished;and the measurement time span was up to 23 years.The measured results indicated that:the in-situ stress state did not change in the past 23 years;the dominant orientation of the horizontal principal stresses in the research area was N24.4°W;and the stress gradients of the maximum and minimum horizontal principal stresses vs.depth were 0.036 and 0.025,respectively.The four feature parameters,kH max,kh min,?m and R,calculated through measured principal stresses,did not change during the 23 years.The research area is in the foot wall of the central faults of the Longmenshan fault belt,and is a passive wall.At the same time,the activities of fault movements and seismic events in the research area are extremely weak.Such a specific regional geodynamic conditions have determined the very stable stress field of this area.Comparing with the other research findings,the calculated ?m reflects the stress accumulative capability of the regional crust in this area,i.e.the magnitude of ?m reflects the strength of regional faults from the point of stress accumulation.Such a finding is consistent with the others′.In the future research,it is possible to use ?m values determined with the measured stresses and the corresponding data from the analysis of activities of fault movements and seismic events to evaluate the earthquake risk of one certain area.
The research area,in Lizhou district,Guanyuan City in the northwest Sichuan Basin,is located between the central faults and front faults of north section of Longmenshan fault belt.The major geological structural units in the research area are semi-platform unit and thrust nappe unit.The lithology is mainly mudstone and silt mudstone formed during the lower Silurian era,which are present almost all over the research area.In order to meet the requirements of one engineering establishment,the in-situ stress measurements by hydraulic fracturing method in four boreholes were accomplished;and the measurement time span was up to 23 years.The measured results indicated that:the in-situ stress state did not change in the past 23 years;the dominant orientation of the horizontal principal stresses in the research area was N24.4°W;and the stress gradients of the maximum and minimum horizontal principal stresses vs.depth were 0.036 and 0.025,respectively.The four feature parameters,kH max,kh min,?m and R,calculated through measured principal stresses,did not change during the 23 years.The research area is in the foot wall of the central faults of the Longmenshan fault belt,and is a passive wall.At the same time,the activities of fault movements and seismic events in the research area are extremely weak.Such a specific regional geodynamic conditions have determined the very stable stress field of this area.Comparing with the other research findings,the calculated ?m reflects the stress accumulative capability of the regional crust in this area,i.e.the magnitude of ?m reflects the strength of regional faults from the point of stress accumulation.Such a finding is consistent with the others′.In the future research,it is possible to use ?m values determined with the measured stresses and the corresponding data from the analysis of activities of fault movements and seismic events to evaluate the earthquake risk of one certain area.
引文
[1]WIEMER S,WYSS M.Mapping the frequency-magnitude distribution inasperities:an improved technique to calculate recurrence times[J].Journal of Geophysical Research,1997,102(B7):15 115–15 128.
[2]WIEMER S,WYSS M.Minimum magnitude of completeness inearthquake catalogs:examples from Alaska,the western United Statesand Japan[J].Bulletin of the Seismological Society of America,2000,90(4):859–869.
[3]WYSS M,SCHORLEMMER D,WIEMER S.Mapping asperities byminima of local recurrence time:San Jacinto-Elsinore fault zones[J].Journal of Geophysical Research,2000,105(B4):7 829–7 844.
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[5]刁桂苓,徐锡伟,陈于高,等.汶川Ms7.9和集集Ms7.6地震前应力场转换现象及其可能的前兆意义[J].地球物理学报,2011,54(1):128–136.(DIAO Guiling,XU Xiwei,CHEN Yugao,et a1.Theprecursory significance of tectonic stress field transformation beforethe Wenchuan Ms 7.9 Earthquake and the Chi-Chi Ms 7.6 Earthquake[J].Chinese Journal of Geophysics,2011,54(1):128–136.(in Chinese))
[6]张培耀,张道仪,朱万宁,等.四川汶川8级地震地应力异常——来自压磁频率应力测量系统的记录[J].地质学报,2008,82(12):1788–1 799.(ZHANG Peiyao,ZHANG Daoyi,ZHU Wanning,et al.Anomalous earth stress of the Ms 8 Wenchuan earthquake in Sichuan,China—recording from piezomagnetic frequency measurement to theearth stress[J].Acta Geologica Sinica,2008,82(12):1 788–1 799.(inChinese))
[7]邱泽华,张宝红.我国钻孔应力–应变地震前兆监测台网的现状[J].国际地震动态,2002,283(6):5–9.(QIU Zehua,ZHANG Baohong.The present situation of the monitoring network of borehole strain-stress for earthquake precursors in China[J].Recent Development ofWorld Seismology,2002,283(6):5–9.(in Chinese))
[8]邱泽华,谢富仁,苏恺之,等.发展钻孔应变观测的战略构想[J].国际地震动态,2004,301(1):7–14.(QIU Zehua,XIE Furen,SUKaizhi,et al.Strategic development outline for borehole strainobservation network[J].Recent Development of World Seismology,2004,301(1):7–14.(in Chinese))
[9]李海亮,李宏.钻孔应变观测现状与展望[J].地质学报,2010,84(6):895–900.(LI Hailiang,LI Hong.Status and developments ofborehole strain observations in China[J].Acta Geologica Sinica,2010,84(6):895–900.(in Chinese))
[10]ZOBACK M L.First and second order patterns of stress in thelithosphere:the world stress map project[J].Journal of GeophysicalResearch,1992,97(B8):11 703–11 728.
[11]谢富仁,陈群策,崔效锋,等.中国大陆地壳应力环境研究[M].北京:地质出版社,2003:39–47.(XIE Furen,CHEN Qunce,CUIXiaofeng,et al.Crustal stress in China[M].Beijing:GeologicalPublishing House,2003:39–47.(in Chinese))
[12]田中丰,藤森邦夫,大塚成昭.地壳应力歪の测定观测による大地震发生の预测[J].地震,1998,50(2):201–208.
[13]LIAO C T,ZHANG C S,WU M L,et al.Stress change near theKunlun fault before and after the Ms 8.1 Kunlun earthquake[J].Geophysical Researcher Letters,2003,30(20):2 027–2 030.
[14]郭啟良,王成虎,马洪生,等.汶川Ms8.0级大震前后的水压致裂原地应力测量[J].地球物理学报,2009,52(5):1395–1 401.(GUO Qiliang,WANG Chenghu,MA Hongsheng,et a1.In-situhydro-fracture stress measurement before and after the Wenchuan Ms8.0 earthquake of China[J].Chinese Journal of Geophysics,2009,52(5):1 395–1 401.(in Chinese))
[15]李传友,宋方敏,冉勇康.龙门山断裂带北段晚第四纪活动性讨论[J].地震地质,2004,26(2):248–258.(LI Chuanyou,SONGFangmin,RAN Yongkang.Late quaternary activity and age constraintof the northern Longmenshan fault zone[J].Seismology and Geology,2004,26(2):248–258.(in Chinese))
[16]李方全,刘鹏,张钧,等.原地应力测量对某核废料处置场地评价的应用[J].岩石力学与工程学报,1994,12(1):55–62.(LIFangquan,LIU Peng,ZHANG Jun,et al.Application of in-situ stressmeasurements to the assessment of a site for nuclear waste disposal[J].Chinese Journal of Rock Mechanics and Engineering,1994,12(1):55–62.(in Chinese))
[17]HAIMSON B C,CORNET F H.ISRM suggested methods for rockstress estimation—part 3:hydraulic fracturing(HF)and/or hydraulictesting of pre-existing fractures(HTPF)[J].International Journal ofRock Mechanics and Mining Sciences,2003,40(7/8):1 011–1 020.
[18]LEE M Y,HAIMSON B C.Statistical evaluation of hydraulicfracturing stress measurement parameters[J].International Journal ofRock Mechanics and Mining Sciences,1989,26(6),447–456.
[19]JAMISON D B,COOK N G W.Note on measured values for the stateof stress in the earth s crust[J].Journal of Geophysical Research,1980,85(B4):1 833–1 838.
[20]CHANG C D,LEE J B,KANG T S.Interaction between regionalstress state and faults:complementary analysis of borehole in situstress and earthquake focal mechanism in southeastern Korea[J].Tectonophysics,2010,485(1/4):164–177.
[21]HAIMSON B C,FAIRHURST C.In-situ stress determination at greatdepth by means of hydraulic fracturing[C]//Proceedings of the 11thSymposium AIME:Rock Mechanics Theory and Practices.NewYork:[s.n.],1970:559–584.
[22]ZOBACK M D,HEALY J.Preliminary stress measurements in centralCalifornia using the hydraulic fracturing technique[J].Pure andApplied Geophysics,1977,115(1/2):135–152.
[23]胡幸平,俞春泉,陶开,等.利用P波初动资料求解汶川地震及其强余震震源机制解[J].地球物理学报,2008,51(6):1711–1 718.(HU Xingping,YU Chunquan,TAO Kai,et al.Focalmechanism solution of Wenchuan earthquake and its strong aftershocks obtained from initial P wave polarity analysis[J].ChineseJournal of Geophysics,2008,51(6):1 711–1 718.(in Chinese))
[24]王成虎,郭啟良,丁立丰,等.工程区高地应力判据研究及实例分析[J].岩土力学,2009,30(8):2359–2364.(WANG Chenghu,GUO Qiliang,DING Lifeng,et al.High in-situ stress criteria forengineering area and a case analysis[J].Rock and Soil Mechanics,2009,30(8):2 359–2 364.(in Chinese))
[25]王艳华,崔效锋,胡幸平,等.基于原地应力测量数据的中国大陆地壳上部应力状态研究[J].地球物理学报,2012(待刊).(WANGYanhua,CUI Xiaofeng,HU Xingping,et al.Study on stress state inupper crust in Chinese continent based on in-situ stress measuringdata[J].Chinese Journal of Geophysics,2012(to be published).(inChinese))
[26]景锋,盛谦,张勇慧,等.中国大陆浅层地壳实测地应力分布规律研究[J].岩石力学与工程学报,2007,26(10):2056–2 062.(JING Feng,SHENG Qian,ZHANG Yonghui,et al.Researchon distribution rule of shallow crustal geostress in China mainland[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(10):2 056–2 062.(in Chinese))
[27]李方全,张钧,刘鹏,等.四川西部水压致裂深部应力测量[C]//地壳构造与地壳应力文集.北京:地震出版社,1988:43–49.(LIFangquan,ZHANG Jun,LIU Peng,et al.Hydro-fracturing in-situstress measurements in deep boreholes in the Northwest of SichuanBasin[C]//Proceedings of the Institute of Crustal Dynamics.Beijing:Seismology Publishing House,1988:43–49.(in Chinese))
[28]GAN W,ZHANG P,SHEN Z K,et al.Present-day crustal motionwithin the Tibetan Plateau inferred from GPS measurements[J].Journal of Geophysical Research,2007,112(B8):1–14.
[29]张培震,闻学泽,徐锡伟,等.2008年汶川8.0级特大地震孕育和发生的多单元组合模式[J].科学通报,2009,54(7):944–953.(ZHANG Peizheng,WEN Xueze,XU Xiwei,et al.Tectonicmodel for the great Wenchuan earthquake of May 12,2008,Sichuan,China[J].Chinese Science Bulletin,2009,54(7):944–953.(inChinese))
[2]WIEMER S,WYSS M.Minimum magnitude of completeness inearthquake catalogs:examples from Alaska,the western United Statesand Japan[J].Bulletin of the Seismological Society of America,2000,90(4):859–869.
[3]WYSS M,SCHORLEMMER D,WIEMER S.Mapping asperities byminima of local recurrence time:San Jacinto-Elsinore fault zones[J].Journal of Geophysical Research,2000,105(B4):7 829–7 844.
[4]WYSS M,MATSUMURA S.Most likely location of largeearthquakes in the Kanto and Tokai areas,Japan,based on the localrecurrence times[J].Physics of the Earth and Planetary Interiors,2002,131(2):173–184.
[5]刁桂苓,徐锡伟,陈于高,等.汶川Ms7.9和集集Ms7.6地震前应力场转换现象及其可能的前兆意义[J].地球物理学报,2011,54(1):128–136.(DIAO Guiling,XU Xiwei,CHEN Yugao,et a1.Theprecursory significance of tectonic stress field transformation beforethe Wenchuan Ms 7.9 Earthquake and the Chi-Chi Ms 7.6 Earthquake[J].Chinese Journal of Geophysics,2011,54(1):128–136.(in Chinese))
[6]张培耀,张道仪,朱万宁,等.四川汶川8级地震地应力异常——来自压磁频率应力测量系统的记录[J].地质学报,2008,82(12):1788–1 799.(ZHANG Peiyao,ZHANG Daoyi,ZHU Wanning,et al.Anomalous earth stress of the Ms 8 Wenchuan earthquake in Sichuan,China—recording from piezomagnetic frequency measurement to theearth stress[J].Acta Geologica Sinica,2008,82(12):1 788–1 799.(inChinese))
[7]邱泽华,张宝红.我国钻孔应力–应变地震前兆监测台网的现状[J].国际地震动态,2002,283(6):5–9.(QIU Zehua,ZHANG Baohong.The present situation of the monitoring network of borehole strain-stress for earthquake precursors in China[J].Recent Development ofWorld Seismology,2002,283(6):5–9.(in Chinese))
[8]邱泽华,谢富仁,苏恺之,等.发展钻孔应变观测的战略构想[J].国际地震动态,2004,301(1):7–14.(QIU Zehua,XIE Furen,SUKaizhi,et al.Strategic development outline for borehole strainobservation network[J].Recent Development of World Seismology,2004,301(1):7–14.(in Chinese))
[9]李海亮,李宏.钻孔应变观测现状与展望[J].地质学报,2010,84(6):895–900.(LI Hailiang,LI Hong.Status and developments ofborehole strain observations in China[J].Acta Geologica Sinica,2010,84(6):895–900.(in Chinese))
[10]ZOBACK M L.First and second order patterns of stress in thelithosphere:the world stress map project[J].Journal of GeophysicalResearch,1992,97(B8):11 703–11 728.
[11]谢富仁,陈群策,崔效锋,等.中国大陆地壳应力环境研究[M].北京:地质出版社,2003:39–47.(XIE Furen,CHEN Qunce,CUIXiaofeng,et al.Crustal stress in China[M].Beijing:GeologicalPublishing House,2003:39–47.(in Chinese))
[12]田中丰,藤森邦夫,大塚成昭.地壳应力歪の测定观测による大地震发生の预测[J].地震,1998,50(2):201–208.
[13]LIAO C T,ZHANG C S,WU M L,et al.Stress change near theKunlun fault before and after the Ms 8.1 Kunlun earthquake[J].Geophysical Researcher Letters,2003,30(20):2 027–2 030.
[14]郭啟良,王成虎,马洪生,等.汶川Ms8.0级大震前后的水压致裂原地应力测量[J].地球物理学报,2009,52(5):1395–1 401.(GUO Qiliang,WANG Chenghu,MA Hongsheng,et a1.In-situhydro-fracture stress measurement before and after the Wenchuan Ms8.0 earthquake of China[J].Chinese Journal of Geophysics,2009,52(5):1 395–1 401.(in Chinese))
[15]李传友,宋方敏,冉勇康.龙门山断裂带北段晚第四纪活动性讨论[J].地震地质,2004,26(2):248–258.(LI Chuanyou,SONGFangmin,RAN Yongkang.Late quaternary activity and age constraintof the northern Longmenshan fault zone[J].Seismology and Geology,2004,26(2):248–258.(in Chinese))
[16]李方全,刘鹏,张钧,等.原地应力测量对某核废料处置场地评价的应用[J].岩石力学与工程学报,1994,12(1):55–62.(LIFangquan,LIU Peng,ZHANG Jun,et al.Application of in-situ stressmeasurements to the assessment of a site for nuclear waste disposal[J].Chinese Journal of Rock Mechanics and Engineering,1994,12(1):55–62.(in Chinese))
[17]HAIMSON B C,CORNET F H.ISRM suggested methods for rockstress estimation—part 3:hydraulic fracturing(HF)and/or hydraulictesting of pre-existing fractures(HTPF)[J].International Journal ofRock Mechanics and Mining Sciences,2003,40(7/8):1 011–1 020.
[18]LEE M Y,HAIMSON B C.Statistical evaluation of hydraulicfracturing stress measurement parameters[J].International Journal ofRock Mechanics and Mining Sciences,1989,26(6),447–456.
[19]JAMISON D B,COOK N G W.Note on measured values for the stateof stress in the earth s crust[J].Journal of Geophysical Research,1980,85(B4):1 833–1 838.
[20]CHANG C D,LEE J B,KANG T S.Interaction between regionalstress state and faults:complementary analysis of borehole in situstress and earthquake focal mechanism in southeastern Korea[J].Tectonophysics,2010,485(1/4):164–177.
[21]HAIMSON B C,FAIRHURST C.In-situ stress determination at greatdepth by means of hydraulic fracturing[C]//Proceedings of the 11thSymposium AIME:Rock Mechanics Theory and Practices.NewYork:[s.n.],1970:559–584.
[22]ZOBACK M D,HEALY J.Preliminary stress measurements in centralCalifornia using the hydraulic fracturing technique[J].Pure andApplied Geophysics,1977,115(1/2):135–152.
[23]胡幸平,俞春泉,陶开,等.利用P波初动资料求解汶川地震及其强余震震源机制解[J].地球物理学报,2008,51(6):1711–1 718.(HU Xingping,YU Chunquan,TAO Kai,et al.Focalmechanism solution of Wenchuan earthquake and its strong aftershocks obtained from initial P wave polarity analysis[J].ChineseJournal of Geophysics,2008,51(6):1 711–1 718.(in Chinese))
[24]王成虎,郭啟良,丁立丰,等.工程区高地应力判据研究及实例分析[J].岩土力学,2009,30(8):2359–2364.(WANG Chenghu,GUO Qiliang,DING Lifeng,et al.High in-situ stress criteria forengineering area and a case analysis[J].Rock and Soil Mechanics,2009,30(8):2 359–2 364.(in Chinese))
[25]王艳华,崔效锋,胡幸平,等.基于原地应力测量数据的中国大陆地壳上部应力状态研究[J].地球物理学报,2012(待刊).(WANGYanhua,CUI Xiaofeng,HU Xingping,et al.Study on stress state inupper crust in Chinese continent based on in-situ stress measuringdata[J].Chinese Journal of Geophysics,2012(to be published).(inChinese))
[26]景锋,盛谦,张勇慧,等.中国大陆浅层地壳实测地应力分布规律研究[J].岩石力学与工程学报,2007,26(10):2056–2 062.(JING Feng,SHENG Qian,ZHANG Yonghui,et al.Researchon distribution rule of shallow crustal geostress in China mainland[J].Chinese Journal of Rock Mechanics and Engineering,2007,26(10):2 056–2 062.(in Chinese))
[27]李方全,张钧,刘鹏,等.四川西部水压致裂深部应力测量[C]//地壳构造与地壳应力文集.北京:地震出版社,1988:43–49.(LIFangquan,ZHANG Jun,LIU Peng,et al.Hydro-fracturing in-situstress measurements in deep boreholes in the Northwest of SichuanBasin[C]//Proceedings of the Institute of Crustal Dynamics.Beijing:Seismology Publishing House,1988:43–49.(in Chinese))
[28]GAN W,ZHANG P,SHEN Z K,et al.Present-day crustal motionwithin the Tibetan Plateau inferred from GPS measurements[J].Journal of Geophysical Research,2007,112(B8):1–14.
[29]张培震,闻学泽,徐锡伟,等.2008年汶川8.0级特大地震孕育和发生的多单元组合模式[J].科学通报,2009,54(7):944–953.(ZHANG Peizheng,WEN Xueze,XU Xiwei,et al.Tectonicmodel for the great Wenchuan earthquake of May 12,2008,Sichuan,China[J].Chinese Science Bulletin,2009,54(7):944–953.(inChinese))
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