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
|
摘要
滨海断裂带为华南亚板块与南海亚板块的分界断裂,是南海北部陆缘的重要控震构造和发震构造。为了探明南海北部海陆过渡带特别是滨海断裂带两侧的深部地壳结构变化特征,在南海北部进行了一系列的海陆地震联测的实验,根据海陆联合深地震探测的结果,南海北部以滨海断裂带为界,断裂带西北部为华南亚板块的典型陆壳,地壳厚30km,上地壳下部存在一层速度为5.5～5.9km.s-1、厚度为3.0～4.0km的低速层,埋深约10～18km;断裂带东南部为南海亚板块减薄型陆壳,厚25～28km,上地壳下部的低速层逐渐减薄并最后尖灭。滨海断裂带为一个上下连续倾向SE的低速破碎带,宽度6～10km。滨海断裂带与上地壳下部的低速层的交接构造部位形成南海北部的重要应力集中带和应变能积聚带,是地震孕育、发生的深部动力学条件。滨海断裂带的发震构造属NEE向与NW向相交切的断裂构造型式,以NEE向的滨海断裂带为主,NW向断裂带为辅。
The Binhai Fault Zone(BFZ) is the boundary fault of the South China subplate and South China Sea subplate,and is an important earthquake -controlling and -triggering structure in the northern margin of South China Sea.To investigate the deep crustal structure across the onshore-offshore transitional zone and BFZ of northern South China Sea,onshore-offshore seismic explorations were carried out in this area.According to the exploration results,the northern South China Sea is divided into two parts by the BFZ.The northwest side of the BFZ is a typical continental crust that belongs to the South China subplate.Its thickness is 30 km.A low velocity layer is found in the lower part of the upper crust.Its velocity is 5.5～5.9 km/s and its thickness is 3.0～4.0 km.The layer is buried at a depth of 10～18 km.The southeast side of the BFZ is a thinning continental crust,which has a thickness of about 25～28 km.The low velocity layer thins gradually and eventually wedges out to the seaside.The BFZ is an up-to-down-continuous low velocity zone,which dips SE and has a width of 6～10 km.The intersection part of the BFZ and the low velocity layer forms an important stress concentrating and strain energy accumulating zone,which serves as a deep dynamical condition for earthquake's pregnancy and occurrence.The pattern of BFZ seismogenic structure is constituted by mutually cutting faults of trending NEE and NW,respectively,where the NEE-trending BFZ is dominant and the NW fault subdominant.
The Binhai Fault Zone(BFZ) is the boundary fault of the South China subplate and South China Sea subplate,and is an important earthquake -controlling and -triggering structure in the northern margin of South China Sea.To investigate the deep crustal structure across the onshore-offshore transitional zone and BFZ of northern South China Sea,onshore-offshore seismic explorations were carried out in this area.According to the exploration results,the northern South China Sea is divided into two parts by the BFZ.The northwest side of the BFZ is a typical continental crust that belongs to the South China subplate.Its thickness is 30 km.A low velocity layer is found in the lower part of the upper crust.Its velocity is 5.5～5.9 km/s and its thickness is 3.0～4.0 km.The layer is buried at a depth of 10～18 km.The southeast side of the BFZ is a thinning continental crust,which has a thickness of about 25～28 km.The low velocity layer thins gradually and eventually wedges out to the seaside.The BFZ is an up-to-down-continuous low velocity zone,which dips SE and has a width of 6～10 km.The intersection part of the BFZ and the low velocity layer forms an important stress concentrating and strain energy accumulating zone,which serves as a deep dynamical condition for earthquake's pregnancy and occurrence.The pattern of BFZ seismogenic structure is constituted by mutually cutting faults of trending NEE and NW,respectively,where the NEE-trending BFZ is dominant and the NW fault subdominant.
引文
[1]Xu H L,Qiu X L,Zhao M H,et al.Characteristics of the crustal structure and hypocentral tectonics in the epicentral area of Nan'ao earthquake(M7.5),the northeastern South China Sea[J].Chinesse Science Bulletin,2006,51(SⅡ):96-106.
[2]刘以宣.华南沿海区域断裂构造分析[M].北京:地震出版社,1981.
[3]魏柏林,冯绚敏,陈定国.东南沿海地震活动特征[M].北京:地震出版社,2001.
[4]龚再升,李思田,谢泰俊,等.南海北部大陆边缘盆地分析与油气聚集[M].北京:科学出版社,1997.
[5]龚再升,李思田.南海北部大陆边缘盆地油气成藏动力学研究[M].北京:科学出版社,2004.
[6]李四光.地质力学概论[M].北京:科学出版社,1973.
[7]李唐根,邱燕,姚永坚.大地构造特征[A].刘光鼎主编.中国海域及邻域地球物理特征[C].北京:科学出版社,1992.
[8]曾维军.广州-巴拉望地学断面[A].刘光鼎主编.中国海域及邻域地球物理特征[C].北京:科学出版社,1992.
[9]姚伯初,曾维军,陈艺中等.南海北部陆缘东部的地壳结构[J].地球物理学报,1994,37(1):27-35.
[10]吴进民.南海地质构造深化的若干问题[A].陈颙等主编.寸丹集(庆贺刘光鼎院士工作50周年学术论文集)[C].北京:科学出版社,1998.
[11]徐杰,张进,周本刚,等.关于南海北部滨海断裂带的研究[J].华南地震,2006,26(4):8-13.
[12]Nazareth J J,Clayton R W.Crustal structure of the Borderland-Continent Transition Zone of southern California adjacent to Los Angeles[J].J Geophys Res,2003,108(B8),2404,doi:10.1029/2001JB000223.
[13]Van Avendonk HJA,Holbrook W S,Okaya D,et al.Continental crust under compression:A seismic refraction study of South Island Geophysical Transect I,South Island,New Zealand[J].J Geophys Res,2004,109(B06302),doi:10.1029/2003JB002790.
[14]McIntosh K,Nakamura Y,Wang T K,et al.Crustal-scale seismic profiles across Taiwan and the western Philippine Sea[J].Tectonophysics,2005,401:23-54.
[15]丘学林,赵明辉,叶春明,等.南海东北部海陆联测与海底地震仪探测[J].大地构造与成矿学,2003,27(4):295-281.
[16]丘学林,陈颙,朱日祥,等.大容量气枪震源在海陆联测中的应用:南海北部试验结果分析[J].科学通报,2007,52(1):1-7.
[17]赵明辉,丘学林,叶春明,等.南海东北部海陆联测与滨海断裂带两侧地壳结构分析[J].地球物理学报,2004,47(5):845-852.
[18]徐辉龙,丘学林,赵明辉,等.南海东北部南澳大地震(M=7.5)震中区的地壳结构特征与震源构造[J].科学通报,2006,51(S2):83-91.
[19]夏少红,丘学林,赵明辉,等.香港与珠三角地区海陆联合地震探测的数据处理[J].热带海洋学报,2007,26(1):35-38.
[20]赵明辉,丘学林,夏少红,等.大容量气枪震源及其波形特征[J].地球物理学报,2008,51(2):558-565.
[21]夏少红,丘学林,赵明辉等.香港外海域海陆地震联测及深部地壳结构研究[J].地球物理学进展,2008,23(5):1389-1397.
[22]Shaohong Xia,Minghui Zhao,Xuelin Qiu,et al.Crustal structure in an onshore-offshore transitional zone near Hong Kong,northern South China Sea[J].Journal of Asian Earth Sciences,2010,37:460-472.
[23]丘学林,刘以宣.南海及其邻区现代构造应力场初探[J].热带海洋,1989,8(2):84-92.
[24]魏柏林,徐辉龙,谢明富.东南沿海地震区的现代构造应力场[J].华南地震,1996,16(4):11-19.
[25]马杏垣.全球地学断面计划[A].见:国家地震局地质研究所主编.现今地球动力学研究及其应用[C].北京:地震出版社,1994,5-9.
[26]姜本鸿,袁登维,吴玉华.壳内低速层与地震活动的关系[J].地质科技情报,1992,11(4):9-15.
[2]刘以宣.华南沿海区域断裂构造分析[M].北京:地震出版社,1981.
[3]魏柏林,冯绚敏,陈定国.东南沿海地震活动特征[M].北京:地震出版社,2001.
[4]龚再升,李思田,谢泰俊,等.南海北部大陆边缘盆地分析与油气聚集[M].北京:科学出版社,1997.
[5]龚再升,李思田.南海北部大陆边缘盆地油气成藏动力学研究[M].北京:科学出版社,2004.
[6]李四光.地质力学概论[M].北京:科学出版社,1973.
[7]李唐根,邱燕,姚永坚.大地构造特征[A].刘光鼎主编.中国海域及邻域地球物理特征[C].北京:科学出版社,1992.
[8]曾维军.广州-巴拉望地学断面[A].刘光鼎主编.中国海域及邻域地球物理特征[C].北京:科学出版社,1992.
[9]姚伯初,曾维军,陈艺中等.南海北部陆缘东部的地壳结构[J].地球物理学报,1994,37(1):27-35.
[10]吴进民.南海地质构造深化的若干问题[A].陈颙等主编.寸丹集(庆贺刘光鼎院士工作50周年学术论文集)[C].北京:科学出版社,1998.
[11]徐杰,张进,周本刚,等.关于南海北部滨海断裂带的研究[J].华南地震,2006,26(4):8-13.
[12]Nazareth J J,Clayton R W.Crustal structure of the Borderland-Continent Transition Zone of southern California adjacent to Los Angeles[J].J Geophys Res,2003,108(B8),2404,doi:10.1029/2001JB000223.
[13]Van Avendonk HJA,Holbrook W S,Okaya D,et al.Continental crust under compression:A seismic refraction study of South Island Geophysical Transect I,South Island,New Zealand[J].J Geophys Res,2004,109(B06302),doi:10.1029/2003JB002790.
[14]McIntosh K,Nakamura Y,Wang T K,et al.Crustal-scale seismic profiles across Taiwan and the western Philippine Sea[J].Tectonophysics,2005,401:23-54.
[15]丘学林,赵明辉,叶春明,等.南海东北部海陆联测与海底地震仪探测[J].大地构造与成矿学,2003,27(4):295-281.
[16]丘学林,陈颙,朱日祥,等.大容量气枪震源在海陆联测中的应用:南海北部试验结果分析[J].科学通报,2007,52(1):1-7.
[17]赵明辉,丘学林,叶春明,等.南海东北部海陆联测与滨海断裂带两侧地壳结构分析[J].地球物理学报,2004,47(5):845-852.
[18]徐辉龙,丘学林,赵明辉,等.南海东北部南澳大地震(M=7.5)震中区的地壳结构特征与震源构造[J].科学通报,2006,51(S2):83-91.
[19]夏少红,丘学林,赵明辉,等.香港与珠三角地区海陆联合地震探测的数据处理[J].热带海洋学报,2007,26(1):35-38.
[20]赵明辉,丘学林,夏少红,等.大容量气枪震源及其波形特征[J].地球物理学报,2008,51(2):558-565.
[21]夏少红,丘学林,赵明辉等.香港外海域海陆地震联测及深部地壳结构研究[J].地球物理学进展,2008,23(5):1389-1397.
[22]Shaohong Xia,Minghui Zhao,Xuelin Qiu,et al.Crustal structure in an onshore-offshore transitional zone near Hong Kong,northern South China Sea[J].Journal of Asian Earth Sciences,2010,37:460-472.
[23]丘学林,刘以宣.南海及其邻区现代构造应力场初探[J].热带海洋,1989,8(2):84-92.
[24]魏柏林,徐辉龙,谢明富.东南沿海地震区的现代构造应力场[J].华南地震,1996,16(4):11-19.
[25]马杏垣.全球地学断面计划[A].见:国家地震局地质研究所主编.现今地球动力学研究及其应用[C].北京:地震出版社,1994,5-9.
[26]姜本鸿,袁登维,吴玉华.壳内低速层与地震活动的关系[J].地质科技情报,1992,11(4):9-15.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心