地壳深部稳定性--震源体破裂机制和摩擦滑动机制的综合研究
COMPREHENSIVE STUDY ON STABILITY OF DEEP CRUST AND UNSTABLE BEHAVIOR OF EARTHQUAKE SOURCE BY BOTH FAILURE MECHANISM AND FRICTIONAL SLIDING MECHANISM
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摘要: 本文通过地壳应力测量结果和地震资料的综合分析,对深部应力状态与断层运动的关系作了讨论:进而应用库仑准则,推导了三维应力作用下完整岩体和已有的任意空间方向断层面的失稳条件及其滑动方式的解析表达式.通过建立描述岩体和已有断层稳定性的两个函数————破裂函数 Fm 和摩擦函数 Ff,给出了应用破裂机制和摩擦滑动机制综合分析地壳稳定性和失稳性态的方法:根据这种分析方法并结合华北平原区的水压致裂应力测量资料,以及孔隙压力、大地热流等观测结果,定量研究了本区地壳的稳定问题,计算并图示了地壳内破裂函数沿深度的分布,以及各种走向和倾向断层面上的摩擦函数和剪应力分布;计算中以 Byerlee 定律作为断层运动的约束条件,并考虑了地壳密度纵向非均匀性导致的垂直应力沿深度的非线性增长以及深部超静水压力的异常孔隙压力作用.结果表明,华北平原区地壳失稳性态主要表现为已有断层的滑动;伴有高剪应力降的断层运动的深度范围在8至2.0多公里之间:陡断层稳定性低于缓断层,其运动方式以走滑为主;本区 NNE-NE 走向的陡断层是一组易震断层,其震时错动为右旋走滑;孔隙压力的增长对地壳稳定性有显著的影响;华北平原区深部高异常孔隙压力是地震活动的一种重要背景.Abstract: In this paper the relation between fault movement and stress state in deep crust is discussed, based on synthetic analysis of the crustal stresses measured over the world and the concerned data of focal mechanism. Using Coulomb criterion for shear failure and frictional slip, an analytical expressions for estimating stabilities of intact rock and existing fault in the crust and for identifying the type of faulting (normal, strike-slip or thrust fault) are derived. By defining the Failure Function Fm and the Friction Function Ff, which may describe steadinesses of crustal rock and existing fault, respectively, a synthetic model is set up to consider both fracturing mechanism and the sliding mechanism. By this model, a method to study stability and unstable behavior of crustal rock and fault at different depths is given.According to the above model, quantitative study on the crustal stability in the North China Plain is made in terms of the measured data of hydraulic fracturing stress, pore-fluid pressure, terrestrical heat flow in this region. The functions Fm and Ff and the shear stresses on faults with different strike directions and dip angles at various depths in this region are calculated. In the calculation the constraint condition of fault movement obeys Byerlee s law, and the depth-dependent nonlinear change in the vertical stress due to inhomogeneity of crustal density and the high anomalous pore-fluid pressure in deep crust of this region are considered.The conclusions are: the unstable behavior of the crust in the North China Plain is not failure of crustal rock but slip on existing fault; the depth range where stick-slip of fault may happen is about from 8 to 20km or more; stability of steep fault is lower than that of gentle sloping fault; the shear stresses in the range where stick-slip may occur are nearly horizontal; the steep faults trending from NNE to NE in this region are liable to produce strong earthquakes, whose co-seismic faultings are, for the most part, right lateral slip; the change in pore fluid pressure in depth remarkably affects the stability of the crust and the increase in pore-fluid pressure, therefore, would be an important factor exciting strong earthquakes in this region. The above theoretical inferences are consistent with the data measured in this region.
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[1] Anderson. E. M——1951. The dynamics of fracture. 2nd ed——Oliver +nd Bovd. Edinburgh,206
[2] P rice. N. J——1966—— h'ault urul joint rlevolopnrent in br——itlle and,senribrittle rock. Pergamon. London.Sibson. R. H.、1977. Fault rocks and fault mechanics. J. Geolophy,133,191——233
[3] Jaeger. J. C. and Cook. N. G. W,1976. Fundanntals onck Mrolrunics. 2nd ed. Chapman and Hall.London. 585PP.
[4] Hubbet. M. and Rubey. W. W,1959. Role of fluid pressure in mechanics of overthrust faulting. Bull. Geol.Anur.,70. 115——205.
[5] Sibson. R. H.,1974. Frictional constrains on thrust. wmench and nornml taults. Nature. Po.s. Sci,249,542——544.
[6] Sibson. R. H.,1982. Fault zone models. heat flow. and depth distribution of earthduakes in the continental crust of the United States. Bull. Seism. Soe. Anr.,72. 151——163.
[7] Haimson. B. C.,1978. The hydrofracturing stress mcasuing method and recent field results. Int. J. Rock Mec. Sci and Geonrech—— Abstr.,15. 167——178
[8] Haimson. B. C. and Rutnmel. F——1982. Hydrofracturing stress measurements in RDP drillhole at Reydre rdur. lceland.J. Geophys. Res., 87, B8. 6631——6649.
[9] Brown. E. T. and Hoek. E——1978. Trends in relationships between measured in——situ stress and depth. Itrt. J.Rock Meeh——Sei.and Geonreoh——Ahstr.,15. 211——215.
[10] 陈家庚、曹新玲、李自强,1982.水力压裂法测定华北地下深部应力.地震学报,4, 35,360.
[11] 丁建民、梁国平. 1985.唐山天津和沧州地区的油井水压致裂应力测量.地震学报,7. 363——373.
[12] 马宗晋、傅征祥、张郧珍,汪成民、张国民、刘德富,1982.中国九大地震.地震出版社,北京.216 pp.
[13] 国家地震局《深部物探成果》编写组,1986.中国地壳上地慢地球物理探测成果.地震出版社.北京,407pp.
[14] iriggs. D. T., Turner. F. J. and Heard, H. C:,1960. Deformation of rock at 500°C to 800°C. Gcul. Ant. Menruir. 79. 39——104.
[15] Tullis. J. and Yund. R. A.,1977 Experimental deformation of dry westerly granite. J. Gerplirs. Res——82,5705——57 I 8.
[16] Edmond. J. M. and Patterson, M. S, 1972. Volume changes during the deformation of rocks at high pres——sure. InI. J. Rock Mcch. Mining Sci.,9, 161——182
[17] Stcsky, R. M——Brace. W. F——Riley, D. K. and Robin, P. Y. F——1974. Fraction in faulted rock at high temperalure and pressure.Tecluttuphy.sic.s, 23, 177——203
[18] 王绳祖、张流,1982.地壳温压条件卜周口店花岗闪长岩的变形破坏.地震地质,4, 4, 68.
[19] 高建理、丁建民、梁国平、郭启良,1987.华北地区盆地内地壳应力随深度的变化.中国地震,3, 4. 82——89.
[20] 杨绪充,1985.济阳坳陷沙河街组区域应力及水动力特征探讨.石油勘探与开发,12, 13——20
[21] Evans. C. R.,Mclvor, D. K. and Magara, K.,1975. Organic matter, compection history and hydrocabon oc currence—— Meckenzie Delta. Imperial oil limited. Calgary, Albeita. Canada. Proceedings o the 9th World Petroleum Congress, 2. 149——157.
[22] Byerlee, J——1978. Friction of rocks. Pure and Appl. Geophys., 116. 615——626.
[23] 梁国平、丁建民,1987.测定水压破裂面方向的地面电测法原理及其在华北地区的测量结果.地壳构造与地壳
[24] 应力文集,1: 88——95,地震出版社,北京.
[25] 张汝惠、解政文、武冀新、谢毅真、刘明,1982.唐山及其邻区热流值的分布.地震地质,4, 4, 57——67.
[26] 汪良谋、张裕明、董瑞树,1982.华北平原及渤海地区新生代地堑的深部扩张及其与强震活动的关系.第二届全国构造地质学术会议论文选集、38——52,地质出版社.北京.
[27] Patterson. M. S——1978 Experirmntal Rock Defomxrtion——The Brittle Field. SpingerVerlag, Berlin Heidelberg. New York, 354PP[1] Anderson. E. M——1951. The dynamics of fracture. 2nd ed——Oliver +nd Bovd. Edinburgh,206
[2] P rice. N. J——1966—— h'ault urul joint rlevolopnrent in br——itlle and,senribrittle rock. Pergamon. London.Sibson. R. H.、1977. Fault rocks and fault mechanics. J. Geolophy,133,191——233
[3] Jaeger. J. C. and Cook. N. G. W,1976. Fundanntals onck Mrolrunics. 2nd ed. Chapman and Hall.London. 585PP.
[4] Hubbet. M. and Rubey. W. W,1959. Role of fluid pressure in mechanics of overthrust faulting. Bull. Geol.Anur.,70. 115——205.
[5] Sibson. R. H.,1974. Frictional constrains on thrust. wmench and nornml taults. Nature. Po.s. Sci,249,542——544.
[6] Sibson. R. H.,1982. Fault zone models. heat flow. and depth distribution of earthduakes in the continental crust of the United States. Bull. Seism. Soe. Anr.,72. 151——163.
[7] Haimson. B. C.,1978. The hydrofracturing stress mcasuing method and recent field results. Int. J. Rock Mec. Sci and Geonrech—— Abstr.,15. 167——178
[8] Haimson. B. C. and Rutnmel. F——1982. Hydrofracturing stress measurements in RDP drillhole at Reydre rdur. lceland.J. Geophys. Res., 87, B8. 6631——6649.
[9] Brown. E. T. and Hoek. E——1978. Trends in relationships between measured in——situ stress and depth. Itrt. J.Rock Meeh——Sei.and Geonreoh——Ahstr.,15. 211——215.
[10] 陈家庚、曹新玲、李自强,1982.水力压裂法测定华北地下深部应力.地震学报,4, 35,360.
[11] 丁建民、梁国平. 1985.唐山天津和沧州地区的油井水压致裂应力测量.地震学报,7. 363——373.
[12] 马宗晋、傅征祥、张郧珍,汪成民、张国民、刘德富,1982.中国九大地震.地震出版社,北京.216 pp.
[13] 国家地震局《深部物探成果》编写组,1986.中国地壳上地慢地球物理探测成果.地震出版社.北京,407pp.
[14] iriggs. D. T., Turner. F. J. and Heard, H. C:,1960. Deformation of rock at 500°C to 800°C. Gcul. Ant. Menruir. 79. 39——104.
[15] Tullis. J. and Yund. R. A.,1977 Experimental deformation of dry westerly granite. J. Gerplirs. Res——82,5705——57 I 8.
[16] Edmond. J. M. and Patterson, M. S, 1972. Volume changes during the deformation of rocks at high pres——sure. InI. J. Rock Mcch. Mining Sci.,9, 161——182
[17] Stcsky, R. M——Brace. W. F——Riley, D. K. and Robin, P. Y. F——1974. Fraction in faulted rock at high temperalure and pressure.Tecluttuphy.sic.s, 23, 177——203
[18] 王绳祖、张流,1982.地壳温压条件卜周口店花岗闪长岩的变形破坏.地震地质,4, 4, 68.
[19] 高建理、丁建民、梁国平、郭启良,1987.华北地区盆地内地壳应力随深度的变化.中国地震,3, 4. 82——89.
[20] 杨绪充,1985.济阳坳陷沙河街组区域应力及水动力特征探讨.石油勘探与开发,12, 13——20
[21] Evans. C. R.,Mclvor, D. K. and Magara, K.,1975. Organic matter, compection history and hydrocabon oc currence—— Meckenzie Delta. Imperial oil limited. Calgary, Albeita. Canada. Proceedings o the 9th World Petroleum Congress, 2. 149——157.
[22] Byerlee, J——1978. Friction of rocks. Pure and Appl. Geophys., 116. 615——626.
[23] 梁国平、丁建民,1987.测定水压破裂面方向的地面电测法原理及其在华北地区的测量结果.地壳构造与地壳
[24] 应力文集,1: 88——95,地震出版社,北京.
[25] 张汝惠、解政文、武冀新、谢毅真、刘明,1982.唐山及其邻区热流值的分布.地震地质,4, 4, 57——67.
[26] 汪良谋、张裕明、董瑞树,1982.华北平原及渤海地区新生代地堑的深部扩张及其与强震活动的关系.第二届全国构造地质学术会议论文选集、38——52,地质出版社.北京.
[27] Patterson. M. S——1978 Experirmntal Rock Defomxrtion——The Brittle Field. SpingerVerlag, Berlin Heidelberg. New York, 354PP
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