SEISMOLOGY AND GEOLOGY ›› 2011, Vol. 33 ›› Issue (4): 901-912.DOI: 10.3969/j.issn.0253-4967.2011.04.014

• Deep structur • Previous Articles     Next Articles

CRUSTAL STRUCTURES AND TECTONICS OF TANGSHAN EARTHQUAKE AREA: RESULTS FROM DEEP SEISMIC REFLECTION PROFILING

LIU Bao-jin1, QU Guo-sheng2, SUN Ming-xin2, LIU Kang2, ZHAO Cheng-bin1, XU Xi-wei3, FENG Shao-ying1, KOU Kun-peng1   

  1. 1. Geophysical Prospecting Center, China Earthquake Administration, Zhengzhou 450002, China;
    2. National Earthquake Response Support Service, China Earthquake Administration, Beijing 100049, China;
    3. Institute of Geology, China Earthquake Administration, Beijing 100029, China
  • Received:2011-10-07 Revised:2011-10-27 Online:2011-12-30 Published:2012-01-12

唐山地震区地壳结构和构造:深地震反射剖面结果

刘保金1, 曲国胜2, 孙铭心2, 刘亢2, 赵成彬1, 徐锡伟3, 酆少英1, 寇昆朋1   

  1. 1. 中国地震局地球物理勘探中心, 郑州 450002;
    2. 中国地震局应急搜救中心, 北京 100049;
    3. 中国地震局地质研究所, 北京 100029
  • 作者简介:刘保金,男,1962年生,1986年毕业于中国科技大学地球物理专业,2010年在中国科学院研究生院获固体地球物理学博士学位,研究员,现主要从事深、浅地震勘探方法研究与应用,电话: 0371-63726328,E-mail: LBJ001@126.com。
  • 基金资助:

    地震行业科研专项"中国地震活动断层探察-华北构造区"(200908001)与河北省城市活断层试验探测项目共同资助

Abstract:

On July 28,1976,the great Tangshan earthquake(M7.8)occurred in the Tangshan area of Hebei Province,which shocked the whole world.Before this earthquake,there was no earthquake with magnitude over M7.0 in this area.After this earthquake,the crustal structures and tectonics around Tangshan earthquake area remain unclear.In order to investigate the fine crustal structures,the main fault geometries and the relations between the deep-shallow tectonics in this area,a deep seismic reflection profiling with 40m receiver spacing and 200m shot spacing as well as 60-fold across the Tangshan Fault zone was carried out in the Fengnan region of Tangshan in 2009.Because our results have much higher spatial resolution than that of previous results of deep geophysical prospecting,some new features of the crustal structures and fault tectonics were revealed by this study.The results show that the thickness of the crust is about 32~34km along the profile,the Moho gradually deepens from east to west.Between Fengnan county and Xuanzhuang town,the reflections in the middle-lower crust and crust-mantle transitional zone are staggered by the deep Tangshan Fault,and dislocation occurs on the Moho on both sides of the deep fault,indicating the strike-slip effect of the deep Tangshan Fault.Tangshan Fault belt revealed by deep seismic reflection profile is a huge intra-continental strike-slip fault,and its shallow part appears as a typical flower-shaped structure,incising and disturbing the lower crust and crust-mantle transitional zone in the deep part.The complex faults and structures coexisting in both deep and shallow parts of the crust are the tectonic background for the Tangshan Earthquake,and also an important factor controlling the earthquake activity in the area.

Key words: Tangshan earthquake area, deep seismic reflection profiling, fine crustal structure, flower-shaped structure, deep-shallow tectonic relations

摘要:

1976年7月28日,在唐山地区发生了7.8级大地震。为了研究该区的地壳结构和断裂的深浅构造关系,2009年,我们在唐山市南部的丰南地区,跨唐山断裂带完成了1条道间距40m、炮间距200m、50次覆盖的深地震反射探测剖面。结果表明: 研究区的地壳厚度为32~34km,莫霍面自东向西逐渐加深,在丰南县和宣庄镇之间,中-下地壳反射和壳幔过渡带反射均被唐山深断裂错开,断裂两侧的莫霍面发生错断,显示出唐山深断裂的走滑作用。反射剖面揭示的唐山断裂带是一条规模较大的陆内走滑断裂,浅部表现为典型的花状构造,在深部切割和扰动了下地壳物质和壳幔过渡带。这种深、浅共存的断裂构造体系是控制该区地震孕育和发生的重要因素,也是唐山地震区的深、浅构造背景。

关键词: 唐山地震区, 深地震反射剖面, 地壳细结构, 花状构造, 深浅构造关系

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