滇西南阿墨江断裂带与2018年墨江M5.9地震
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摘要
野外调查表明,阿墨江断裂Ⅲ级夷平面和T4阶地上发育断层垭口,其下地貌面则无断层地貌显示;断层构造岩胶结紧密或呈半固结状,少有断层泥发育;SEM测年显示早更新世活动,断层泥ESR年龄为549±54ka,断层上覆中—上更新统残坡积土未被切穿或发生构造变形;说明该断裂带最新活动时代为早—中更新世。2018年墨江M5.9地震等震线长轴呈与断裂带走向一致的NW方向,指示此次地震的发震构造为阿墨江断裂带西支。受青藏高原物质向东南挤出的影响,震中所在的思茅块体作S向运动。虽然阿墨江断裂带晚第四纪无明显的地表活动迹象,但因该断裂带本身构成了宽阔的构造软弱带,在近SN向挤压应力场作用下,局部地区的应力集中仍可能导致新的破裂并触发类似墨江M5.9地震的中-强地震活动。从区域上看,云南还存在构造条件与之相似的断裂带,如滇东地区的弥勒-师宗断裂带,历史上沿该断裂带曾发生11次5级以上中-强地震。因此,在区域地震危险性评价中,还应该关注第四纪活动迹象不明显,但仍有潜在发震危险性的区域性大断裂。
Field investigation shows that fault mouths are developed on the planation surface Ⅲ and river terrace 4 in the Amojiang fault zone, and below them there is no indication of fault landforms.Structural rocks dated by SEM are Early Pleistocene in age and are cemented compactly or half consolidated,and a few fault gouges dated by ESR as 549±54 ka and developed on the fault plains and Middle—Upper Pleistocene deposits covering the faults have not been displaced or deformed tectonically. All these phenomena suggest that the fault zone was mainly active in Early—Middle Pleistocene. The 2018 Mojaing M5.9 earthquake occurred on the western branch of the Amojiang fault zone,and the long azimuth of isoseismal lines of the quake was in NW direction, consistent with the strike of the fault,suggesting that the seismogenic structure of the quake should be the western branch of the fault zone.Despite of no signs of activeness in Late Quaternary along the fault zone,the Amojiang fault zone itself became a broad relative weak belt. Affected by the SE extrusion of the Tibetan Plateau matters, the Simao block where the epicenter is located moved southward.Although the Amojiang fault zone was in absence of evident ground activity during Late Quaternary, the zone itself formed broad weak structural belt. Under the circumstance of the NS-trending tectonic compression stresses,stresses concentration in local area could also give rise to new break and induce the middle-large earthquakes like the Amojiang M5.9 earthquake.Regionally,there are similar fault zones in structural conditions, such as the Mile-Shizong fault zone in southeastern Yunnan, along which there historically occurred 11 earthquakes of magnitude over M5.0. Therefore, the researchers should pay attention to the regional large faults which were not sub-surficially active in Late Quaternary, but still have potential seismic risk in the regional seismic risk assessment.
Field investigation shows that fault mouths are developed on the planation surface Ⅲ and river terrace 4 in the Amojiang fault zone, and below them there is no indication of fault landforms.Structural rocks dated by SEM are Early Pleistocene in age and are cemented compactly or half consolidated,and a few fault gouges dated by ESR as 549±54 ka and developed on the fault plains and Middle—Upper Pleistocene deposits covering the faults have not been displaced or deformed tectonically. All these phenomena suggest that the fault zone was mainly active in Early—Middle Pleistocene. The 2018 Mojaing M5.9 earthquake occurred on the western branch of the Amojiang fault zone,and the long azimuth of isoseismal lines of the quake was in NW direction, consistent with the strike of the fault,suggesting that the seismogenic structure of the quake should be the western branch of the fault zone.Despite of no signs of activeness in Late Quaternary along the fault zone,the Amojiang fault zone itself became a broad relative weak belt. Affected by the SE extrusion of the Tibetan Plateau matters, the Simao block where the epicenter is located moved southward.Although the Amojiang fault zone was in absence of evident ground activity during Late Quaternary, the zone itself formed broad weak structural belt. Under the circumstance of the NS-trending tectonic compression stresses,stresses concentration in local area could also give rise to new break and induce the middle-large earthquakes like the Amojiang M5.9 earthquake.Regionally,there are similar fault zones in structural conditions, such as the Mile-Shizong fault zone in southeastern Yunnan, along which there historically occurred 11 earthquakes of magnitude over M5.0. Therefore, the researchers should pay attention to the regional large faults which were not sub-surficially active in Late Quaternary, but still have potential seismic risk in the regional seismic risk assessment.
引文
[1]云南省地质矿产局.云南省区域地质志[M].北京:地质出版社,1990.
[2]安晓文,常祖峰.云南第四纪活动断裂[M].北京:地震出版社,2018.
[3]虢顺民,计凤桔,向宏发,等.红河活动断裂带[M].北京:海洋出版社,2001.
[4]向宏发,韩竹军,虢顺民,等.红河断裂带大型右旋走滑运动与伴生构造地貌变形[J].地震地质,2004,26(4):597-610.
[5]向宏发,虢顺民,张晚霞,等.红河断裂带南段中新世以来大型右旋位错量的定量研究[J].地震地质,2007,29(1):34-50.
[6]Tapponnier P, Peltzer G, Le Dain A Y, et al. Propagating extrusion tectonics in Asia:New insights from simple experiments with plasticine[J]. Geology,1982,10(12):611-616.
[7]Tapponnier P, Lacassin R, Leloup P H, et al. The Ailao Shan/Red River metamorphic belt:Tertiary left-lateral shear between Indochina and south China[J]. Nature,1990,343(6257):431-437.
[8]Leloup P H, Kienast J R. High-temperature metamorphism in a major strike-slip shear zone:The Ailao Shan-Red River, People's Republic of China[J]. Earth Planet. Sci. Lett.,1993,188(1/4):213-234.
[9]Leloup P H, Lacassin R, Tapponnier P, et al. TheAilao Shan-Red River shear zone(Yunnan, China), Tertiary transform boundary of Indochina[J]. Tectonophysics,1995,251(1/4):3-10, 13-84.
[10]Allen C R, Gillespie A R, Yuan H, et al.Red river and associated faults, Yunnan province, China:Quaternary geology, slip rates, and Seismic hazard[J]. Geol. Soc. Am. Bull., 1984, 95(6):686-700.
[11]Schoenbohm L M, Burchfiel B C, Chen L Z, et al.Miocene to present activity along the Red River fault, China, in the context of continental extrusion, upper-crustal rotation, and lower-crustal flow[J]. Geol. Soc. Am. Bull.,2006,118(5/6):672-688.
[12]虢顺民,汪洋,计凤桔.云南思茅—普洱地区中强震群发生的构造机制[J].地震研究,1999,22(2):105-115.
[13]朱成男,周瑞琦.普洱磨黑6.8级地震区地质构造基本特征[J].地震研究,1981,4(1):69-76.
[14]杨晓平,陈立春,马文涛,等. 2007年6月3日宁洱6.4级地震地表变形的构造分析和解释[J].地震学报,2008,30(2):165-175.
[15]常祖峰,陈晓利,陈宇军,等.景谷Ms6.6地震同震地表破坏特征与孕震构造[J].地球物理学报,2016,59(7):2539-2552.
[16]吴坤罡,吴中海,徐甫坤,等.滇西南2014年景谷中-强震群的地质构造成因——茶房-普文断裂带贯通过程的构造响应[J].地质通报,2016,35(1):140-151.
[17]Tapponnier P. Propogation extrution tectonics in Aisa:New insights from simple experiments with plasticine[J]. Geology, 1982,10:61-616.
[18]Tapponnier P, Lacassin R, Leloup P H, et al. The Ailaoshan/Red River metamorphic belt:Tertiary left-lateral shear between Indochina and south China[J]. Nature, 1990,343:431-437.
[19]Minster J B, Jordan T H. Present-day plate motions[J]. J. Geophys.Res.,1978,83(B11):5331-5354.
[20]钟大赉,丁林.青藏高原的隆起过程及其机制探讨[J].中国科学(D辑),1996, 26(4):289-295.
[21]张培震,王琪,马宗晋.青藏高原现今构造变形特征与GPS速度场[J].地学前缘,2002,9(2):442-450.
[22]张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学(D辑),2003,33(S):12-20.
[23]许志琴,张建新,徐惠芬.中国主要大陆山链韧性剪切带及动力学[M].北京:地质出版社,1997.
[24]吴中海,龙长兴,范桃园,等.青藏高原东南缘弧形旋扭活动构造体系及其动力学特征与机制[J].地质通报,2015,32(1):1-31.
[25]计凤桔,郑荣章,李建平,等.滇东、滇西地区主要河流低阶地地貌面年代学研究[J].地震地质,2000,22(3):265-276.
[26]常祖峰,张艳凤,周青云,等. 2013年洱源Ms5.5地震烈度分布及震区活动构造背景研究[J].中国地震,2014,30(4):560-570.
[27]黄小龙,吴中海,蒋瑶,等. 2013年3月3日云南大理洱源Ms5.5地震烈度分布及发震构造[J].地质通报,34(1):135-145.
[28]朱凤鸣,吴戈.一九七五年海城地震[M].北京:地震出版社,1982.
[29]阚荣举,张四昌,晏凤桐.我国西南地区现代构造应力场与现代构造活动特征的探讨[J].地球物理学报, 1977, 20(2):96-109.
(1)云南省地质调查局第二区域地质测量队.1:20万普洱幅区域调查报告.1976.
(2)云南省地质局第二区域地质测量队.1:20万墨江幅区域调查报告.1975.
[2]安晓文,常祖峰.云南第四纪活动断裂[M].北京:地震出版社,2018.
[3]虢顺民,计凤桔,向宏发,等.红河活动断裂带[M].北京:海洋出版社,2001.
[4]向宏发,韩竹军,虢顺民,等.红河断裂带大型右旋走滑运动与伴生构造地貌变形[J].地震地质,2004,26(4):597-610.
[5]向宏发,虢顺民,张晚霞,等.红河断裂带南段中新世以来大型右旋位错量的定量研究[J].地震地质,2007,29(1):34-50.
[6]Tapponnier P, Peltzer G, Le Dain A Y, et al. Propagating extrusion tectonics in Asia:New insights from simple experiments with plasticine[J]. Geology,1982,10(12):611-616.
[7]Tapponnier P, Lacassin R, Leloup P H, et al. The Ailao Shan/Red River metamorphic belt:Tertiary left-lateral shear between Indochina and south China[J]. Nature,1990,343(6257):431-437.
[8]Leloup P H, Kienast J R. High-temperature metamorphism in a major strike-slip shear zone:The Ailao Shan-Red River, People's Republic of China[J]. Earth Planet. Sci. Lett.,1993,188(1/4):213-234.
[9]Leloup P H, Lacassin R, Tapponnier P, et al. TheAilao Shan-Red River shear zone(Yunnan, China), Tertiary transform boundary of Indochina[J]. Tectonophysics,1995,251(1/4):3-10, 13-84.
[10]Allen C R, Gillespie A R, Yuan H, et al.Red river and associated faults, Yunnan province, China:Quaternary geology, slip rates, and Seismic hazard[J]. Geol. Soc. Am. Bull., 1984, 95(6):686-700.
[11]Schoenbohm L M, Burchfiel B C, Chen L Z, et al.Miocene to present activity along the Red River fault, China, in the context of continental extrusion, upper-crustal rotation, and lower-crustal flow[J]. Geol. Soc. Am. Bull.,2006,118(5/6):672-688.
[12]虢顺民,汪洋,计凤桔.云南思茅—普洱地区中强震群发生的构造机制[J].地震研究,1999,22(2):105-115.
[13]朱成男,周瑞琦.普洱磨黑6.8级地震区地质构造基本特征[J].地震研究,1981,4(1):69-76.
[14]杨晓平,陈立春,马文涛,等. 2007年6月3日宁洱6.4级地震地表变形的构造分析和解释[J].地震学报,2008,30(2):165-175.
[15]常祖峰,陈晓利,陈宇军,等.景谷Ms6.6地震同震地表破坏特征与孕震构造[J].地球物理学报,2016,59(7):2539-2552.
[16]吴坤罡,吴中海,徐甫坤,等.滇西南2014年景谷中-强震群的地质构造成因——茶房-普文断裂带贯通过程的构造响应[J].地质通报,2016,35(1):140-151.
[17]Tapponnier P. Propogation extrution tectonics in Aisa:New insights from simple experiments with plasticine[J]. Geology, 1982,10:61-616.
[18]Tapponnier P, Lacassin R, Leloup P H, et al. The Ailaoshan/Red River metamorphic belt:Tertiary left-lateral shear between Indochina and south China[J]. Nature, 1990,343:431-437.
[19]Minster J B, Jordan T H. Present-day plate motions[J]. J. Geophys.Res.,1978,83(B11):5331-5354.
[20]钟大赉,丁林.青藏高原的隆起过程及其机制探讨[J].中国科学(D辑),1996, 26(4):289-295.
[21]张培震,王琪,马宗晋.青藏高原现今构造变形特征与GPS速度场[J].地学前缘,2002,9(2):442-450.
[22]张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学(D辑),2003,33(S):12-20.
[23]许志琴,张建新,徐惠芬.中国主要大陆山链韧性剪切带及动力学[M].北京:地质出版社,1997.
[24]吴中海,龙长兴,范桃园,等.青藏高原东南缘弧形旋扭活动构造体系及其动力学特征与机制[J].地质通报,2015,32(1):1-31.
[25]计凤桔,郑荣章,李建平,等.滇东、滇西地区主要河流低阶地地貌面年代学研究[J].地震地质,2000,22(3):265-276.
[26]常祖峰,张艳凤,周青云,等. 2013年洱源Ms5.5地震烈度分布及震区活动构造背景研究[J].中国地震,2014,30(4):560-570.
[27]黄小龙,吴中海,蒋瑶,等. 2013年3月3日云南大理洱源Ms5.5地震烈度分布及发震构造[J].地质通报,34(1):135-145.
[28]朱凤鸣,吴戈.一九七五年海城地震[M].北京:地震出版社,1982.
[29]阚荣举,张四昌,晏凤桐.我国西南地区现代构造应力场与现代构造活动特征的探讨[J].地球物理学报, 1977, 20(2):96-109.
(1)云南省地质调查局第二区域地质测量队.1:20万普洱幅区域调查报告.1976.
(2)云南省地质局第二区域地质测量队.1:20万墨江幅区域调查报告.1975.
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