福建—台湾海峡深部地壳结构探测与滨海断裂带性质研究
|
摘要
基于2012年实施的漳浦—下洋—武平人工地震爆破探测数据以及2015年实施的陆海联测HX07的数据,用射线追踪和正演走时拟合方法,获得了福建南部—台湾海峡的初步二维纵波速度模型。剖面显示:滨海断裂带表现为宽约20 km的切穿地壳的破碎低速带,与其两侧的地壳结构存在较大的横向差异,莫霍面在滨海断裂带处发生较大的突变,其深度由左侧的30 km左右抬升至右侧的28.8 km左右,上下地壳厚度比亦由靠陆一侧的1:1降至向海一侧的0.5:1;上述特征表明滨海断裂带是华南地块正常型陆壳与海区减薄型陆壳的分界断裂。地壳速度在海陆过渡带偏高,康拉德面和莫霍面在此处也有显著抬升,推测其可能是在地壳的伸展拉张及太平洋板块与菲律宾海板块向欧亚大陆板块的俯冲的共同作用下,深部软流圈物质沿着长乐—诏安深大断裂上侵形成的。
Based on the data of the blasting seismic survey line Zhangpu-Xiyang-Wuping in 2012 and the data of Onshore-offshore seismic experiment HX07 carried out in 2015, we got the two-dimensional longitudinal wave velocity model of southern part of Fujian-Taiwan Strait Region. The profile shows that the Littoral Fault Zone manifest as a 20 km wide low-velocity fracture zone that cuts through the crust. There is a large lateral difference between crustal structures on both sides of the crust. The Moho has a big mutation at the Littoral Fault Zone. Its depth is raised from about 30 km on the left to about 28.8 km on the right. The thickness ratio of the upper and lower crusts is also reduced from 1:1 on the land side to 0.5:1 on the seaward side.. The above characteristics show that the Littoral Fault Zone is the boundary fault between the normal continental crust and the thinned continental crust in the South China block. The crustal velocity is high in the transition zone between sea and land, and the Conrad and Moho are also significantly uplifted here. It is speculated that the deep asthenosphere may have formed along the Changle-Zhaoan deep major fault under the joint extension of crustal extension and subduction of Pacific plate and Philippine sea plate to Eurasian plate.
Based on the data of the blasting seismic survey line Zhangpu-Xiyang-Wuping in 2012 and the data of Onshore-offshore seismic experiment HX07 carried out in 2015, we got the two-dimensional longitudinal wave velocity model of southern part of Fujian-Taiwan Strait Region. The profile shows that the Littoral Fault Zone manifest as a 20 km wide low-velocity fracture zone that cuts through the crust. There is a large lateral difference between crustal structures on both sides of the crust. The Moho has a big mutation at the Littoral Fault Zone. Its depth is raised from about 30 km on the left to about 28.8 km on the right. The thickness ratio of the upper and lower crusts is also reduced from 1:1 on the land side to 0.5:1 on the seaward side.. The above characteristics show that the Littoral Fault Zone is the boundary fault between the normal continental crust and the thinned continental crust in the South China block. The crustal velocity is high in the transition zone between sea and land, and the Conrad and Moho are also significantly uplifted here. It is speculated that the deep asthenosphere may have formed along the Changle-Zhaoan deep major fault under the joint extension of crustal extension and subduction of Pacific plate and Philippine sea plate to Eurasian plate.
引文
[1]丁祥焕,王耀东,叶盛基.福建东南沿海活动断裂与地震[M].福州:福建科学技术出版社,1999.
[2]黄昭,王善雄.台湾海峡滨海断裂带的构造特征与活动性[J].大地测量与地球动力学,2006,26(3):16-22.
[3]詹文欢,孙宗勋,唐诚等,华南滨海断裂带及其对台湾海峡地震活动的控制作用[J].热带海洋学报,2004, 23(4):19-24.
[4]曹敬贺.南海北部珠江口海域滨海断裂带的地震学特征研究[D].北京:中国科学院大学, 2014.
[5]赵明辉,丘学林,叶春明,等.南海东北部海陆深地震联测与滨海断裂带两侧地壳结构分析.地球物理学报[J].2004, 47(5):845-852.
[6]杨肖琪,宋文隆,陈承惠.台湾海峡地质构造特征[J].台湾海峡,1996,15(2):127-135.
[7]钟建强.滨海断裂带之所在及其活动性初探[J].华南地震, 1987,7(4):1-7.
[8]薛佳谋.南澎大断裂的发育特征及其发震意义[J].华南地震, 1986,6(3):20-28.
[9]卢华复.关于华夏古陆[J].高校地质学报,2006, 12(4):413-417.
[10]赵海玲,狄永军,刘振文,等.东南沿海地区新生代火山作用和地幔柱[J].地质学报,2004,78(6):781-788.
[11]闫培,张艺峰,李普春,等.台湾海峡深地震探测:HX9测线实验及初步成果[J].中国地震,2015, 31(1):27-35.
[12]王笋,谢志招,张艺峰,等.晋江外海沉积层上地壳速度结构的二维层析成像[J].地球物理学进展, 2015, 30(1):106-110.
[13]伊周勋,赖明惠,熊绍柏,等.华南连县—博罗—港口地带地壳结构及速度分布的爆炸地震探测结果[J].地球物理学报, 1999, 42(3):383-392.
[14] Zelt C A,Smith R B. Seismic traveltime inversion for 2-D crustal velocity structure[J]. Geophysical Journal International,1992, 108(1):16-34.
[15]徐辉龙,叶春明,丘学林,等.南海北部滨海断裂带的深部地球物理探测及其发震构造研究[J].华南地震,2010,30(S1):10-18.
[16]杨小秋,施小斌,许鹤华.台湾海峡及其邻区现今构造应力场数值模拟[J].地球物理学报,2012,55(7):2307-2318.
[17]张季生,高锐,李秋生,等.台湾海峡及邻区地球物理特征及地壳密度结构[J].地质论, 2008, 54(5):1-6.
[18]朱金芳,方盛明,张先康,等.漳州盆地及其邻区地壳深部结构的探测与研究[J].中国地震,2006,22(4):405-417.
[19]韩凯.华南东南部壳/幔电性结构特征及其动力学背景研究[D].长春:吉林大学,2012.
[20] Wessel P,Smith W H F. New version of the generic mapping tools released. EOS Trans[J]. AGU,1995,76(33):329.
[2]黄昭,王善雄.台湾海峡滨海断裂带的构造特征与活动性[J].大地测量与地球动力学,2006,26(3):16-22.
[3]詹文欢,孙宗勋,唐诚等,华南滨海断裂带及其对台湾海峡地震活动的控制作用[J].热带海洋学报,2004, 23(4):19-24.
[4]曹敬贺.南海北部珠江口海域滨海断裂带的地震学特征研究[D].北京:中国科学院大学, 2014.
[5]赵明辉,丘学林,叶春明,等.南海东北部海陆深地震联测与滨海断裂带两侧地壳结构分析.地球物理学报[J].2004, 47(5):845-852.
[6]杨肖琪,宋文隆,陈承惠.台湾海峡地质构造特征[J].台湾海峡,1996,15(2):127-135.
[7]钟建强.滨海断裂带之所在及其活动性初探[J].华南地震, 1987,7(4):1-7.
[8]薛佳谋.南澎大断裂的发育特征及其发震意义[J].华南地震, 1986,6(3):20-28.
[9]卢华复.关于华夏古陆[J].高校地质学报,2006, 12(4):413-417.
[10]赵海玲,狄永军,刘振文,等.东南沿海地区新生代火山作用和地幔柱[J].地质学报,2004,78(6):781-788.
[11]闫培,张艺峰,李普春,等.台湾海峡深地震探测:HX9测线实验及初步成果[J].中国地震,2015, 31(1):27-35.
[12]王笋,谢志招,张艺峰,等.晋江外海沉积层上地壳速度结构的二维层析成像[J].地球物理学进展, 2015, 30(1):106-110.
[13]伊周勋,赖明惠,熊绍柏,等.华南连县—博罗—港口地带地壳结构及速度分布的爆炸地震探测结果[J].地球物理学报, 1999, 42(3):383-392.
[14] Zelt C A,Smith R B. Seismic traveltime inversion for 2-D crustal velocity structure[J]. Geophysical Journal International,1992, 108(1):16-34.
[15]徐辉龙,叶春明,丘学林,等.南海北部滨海断裂带的深部地球物理探测及其发震构造研究[J].华南地震,2010,30(S1):10-18.
[16]杨小秋,施小斌,许鹤华.台湾海峡及其邻区现今构造应力场数值模拟[J].地球物理学报,2012,55(7):2307-2318.
[17]张季生,高锐,李秋生,等.台湾海峡及邻区地球物理特征及地壳密度结构[J].地质论, 2008, 54(5):1-6.
[18]朱金芳,方盛明,张先康,等.漳州盆地及其邻区地壳深部结构的探测与研究[J].中国地震,2006,22(4):405-417.
[19]韩凯.华南东南部壳/幔电性结构特征及其动力学背景研究[D].长春:吉林大学,2012.
[20] Wessel P,Smith W H F. New version of the generic mapping tools released. EOS Trans[J]. AGU,1995,76(33):329.