雷琼拗陷地壳结构特征
|
摘要
根据1984~1985年在雷琼地区完成、长约210 km的白延—江洪深地震测深资料,应用有限差分法、时间项法反演和二维非均匀动力学射线追踪等方法,得到白延—江洪地壳剖面的二维非均匀构造图像.结果显示:琼北及雷州半岛地壳厚约25~26 km,地壳平均速度在琼州海峡南段琼北凸起约6.16 km.s-1,海峡北段雷琼拗陷区约5.70km.s-1;地壳速度偏低,下地壳尤为明显,仅约6.3~6.5 km.s-1;结晶基底显示为厚约2~4 km、速度5.5~6.0 km.s-1的速度梯度带,Moho界面上、下界面速度分别是6.5 km.s-1和8.05 km.s-1的一级速度间断面,没有发现明显的壳幔过渡带.白延—江洪剖面位于雷琼拗陷更新世玄武岩覆盖区,推测地壳厚度减薄以及低速度构造主要反映了该区域自新生代以来一直延续至第四系晚期的多期火山岩浆喷发,热地幔对地壳底部的底浸、拆层与地壳仍处于相对温热状态相关.
Seismic data obtained from an about 210 km long Baiyan-Jianghong deep seismic sounding profile,which was completed in Leiqiong area in 1984 and 1985, were processed by means of finite difference tomography,time term inversion and 2-D dynamic ray tracing methods.And 2-D inhomogeneous crustal structure images along Baiyan-Jianghong seismic line were determined.The results show that the crustal thickness in northern Hainan province and Leizhou Peninsula is about 25～26 km.In northern Hainan island embossment of the southern part of Qiongzhou Straits,the average crustal velocity is about 6.16 km·s~(-1) and 5.70 km·s~(-1) in the Leiqiong depression of northern segment of Qiongzhou Straits.The crustal velocity is particular low and especially obvious in lower crust where it is only about 6.3～6.5 km·s~(-1);The crystalline basement presents a velocity gradient belt,the thickness of which is about 2～4 km and the velocity is approximately 5.5～6.0 km·s~(-1).Moho,the velocities of which on its two sides are 6.5 km·s~(-1) and 8.05 km·s~(-1) respectively,shows one-order velocity discontinuity,and there is no obvious crust-mantle transitional zone to be found.Because the Baiyan-Jianghong seismic line lies in the Leiqiong depression area with basalt covering of the Pleistocene,it is suggested that the thinner crust and lower velocity in this area mainly reflect the multi-erupting of volcanic magma from the Cenozoic till the late Quaternary as well as the underplating and delaminating of hot mantle to the crustal bottom which are interrelated with the crust be still in comparatively hot state.
Seismic data obtained from an about 210 km long Baiyan-Jianghong deep seismic sounding profile,which was completed in Leiqiong area in 1984 and 1985, were processed by means of finite difference tomography,time term inversion and 2-D dynamic ray tracing methods.And 2-D inhomogeneous crustal structure images along Baiyan-Jianghong seismic line were determined.The results show that the crustal thickness in northern Hainan province and Leizhou Peninsula is about 25～26 km.In northern Hainan island embossment of the southern part of Qiongzhou Straits,the average crustal velocity is about 6.16 km·s~(-1) and 5.70 km·s~(-1) in the Leiqiong depression of northern segment of Qiongzhou Straits.The crustal velocity is particular low and especially obvious in lower crust where it is only about 6.3～6.5 km·s~(-1);The crystalline basement presents a velocity gradient belt,the thickness of which is about 2～4 km and the velocity is approximately 5.5～6.0 km·s~(-1).Moho,the velocities of which on its two sides are 6.5 km·s~(-1) and 8.05 km·s~(-1) respectively,shows one-order velocity discontinuity,and there is no obvious crust-mantle transitional zone to be found.Because the Baiyan-Jianghong seismic line lies in the Leiqiong depression area with basalt covering of the Pleistocene,it is suggested that the thinner crust and lower velocity in this area mainly reflect the multi-erupting of volcanic magma from the Cenozoic till the late Quaternary as well as the underplating and delaminating of hot mantle to the crustal bottom which are interrelated with the crust be still in comparatively hot state.
引文
[1]丁原章,李,时振梁等.海南岛北部地震研究文集.北京:地震出版社,1988Ding Y Z,Li P,Shi Z L,et al.Collected Works of EarthquakeResearch in North Hainan Island(in Chinese).Beijing:Seismological Press,1988
[2]林中洋,胡鸿翔,朱良保等.雷琼地区地壳结构的初步结果.见:丁原章等编.海南岛北部地震研究文集.北京:地震出版社,1988.127~139Lin Z Y,Hu H X,Zhu L B,et al.The primary results of crustalstructures in Leiqiong area.In:Ding Y Z eds.Collected Works ofEarthquake Research in North Hainan Island(in Chinese).Beijing:Seismological Press,1988.127~139
[3]章林云,王振明.琼东北地区人工地震测深研究.见:丁原章等编.海南岛北部地震研究文集.北京:地震出版社,1988.112~116Zhang L Y,Wang Z M.Study of DSS in Northeast Hainan Island.In:Ding Y Z eds.Collected Works of Earthquake Research in NorthHainan Island(in Chinese).Beijing:Seismological Press,1988.112~116
[4]彭承光,张福来,王业兴等.广东、海南地震构造.马杏垣主编.中国岩石圈动力学地图集.北京:中国地图出版社,1989.46Peng C G,Zhang F L,Wang Y X,et al.Seismotectonics ofGuangdong and Hainan provinces.In:Ma X Y ed.LithosphericDynamics Atlas of China(in Chinese).Beijing:China CartographicPublishing House,1989.46
[5]嘉世旭,刘昌铨.华北地区人工地震测深震相与地壳结构研究.地震地质,1995,17(2):97~105Jia S X,Liu C Q.Study on the seismic phase of DSS in NorthChina.Seismology and Geology(in Chinese),1995,17(2):97~105
[6]Vidale J.Finite-difference calculation of travel-times.Bull Seism.Soc.Am.,1988,78:2062~2076
[7]Hole J A.Nonlinear high_resolution three_dimensional seismic traveltime tomography.J.Geophys.Res.,1992,97:456~501
[8]段永红,赖晓岭,张先康等.二、三维有限差分走时层析成像.华北地震科学,1999,17(4):53~60Duan Y H,Lai X L,Zhang X K,et al.2-D and 3-D finitedifference seismic traveltime tomography.Earthquake Science inNorth China(in Chinese),1999,17(4):53~60
[9]陈,陈运泰.晋中南地区地壳结构的初步研究.地球物理学报,1974,17(3):186~199Chen Y,Chen Y T.The primary study of crustal structures in centraland southern region of Shanxi Province.Chinese J.Geophys.(inChinese),1974,17(3):186~199
[10]杨卓欣,张文彬,杨键.华北北部结晶基底-Pg波时间项法分析.见:河南地球物理科学论文集.郑州:河南科学技术出版社,1993.93~96Yang Z X,Zhang W B,Yang J.The crystalline basement innorthern area of North China—Pg wave time term analysis.In:Collected Works of Geophysics in Henan(in Chinese).Zhengzhou:Henan Science&Technology Press,1993.93~96
[11]Cerveny V.Ray theoretical seismograms for laterally inhomogenousstructures.Geophys.,1979,46:335~342
[12]嘉世旭,刘昌铨.动力学射线追踪方法及其在二维非均匀介质理论地震图计算中的应用.见:国家地震局科技司编.中国大陆深部构造的研究与进展.北京:地质出版社,1988.279~287Jia S X,Liu C Q.Dynamic ray tracing and its application to thecomputation of synthetic seismograms in 2-D heterogeneous medium.In:Development in the Research of Deep Structures of China’sContinent(in Chinese).Beijing:Geological Publishing House,1988.279~287
[13]地质矿产部地球物理地球化学勘查研究所,地质矿产部区域重力方法技术中心.1:400万中国布格重力异常图.地质矿产部,1989The Institute of Geophysical and Geochemical Exploration and theTechnical Center of Regional Gravity Survey.The Bouguer gravityanomaly map of China on the scale of 1:4000000(in Chinese).Ministry of Geology and Mineral Resources,1989
[14]嘉世旭,张先康,方盛明.华北裂陷盆地不同块体地壳结构及演化研究.地学前缘,2001,8(2):259~266Jia S X,Zhang X K,Fang S M.Research on the crustal structureand evolution of different blocks in North China rift-depression basin.Earth Science Frontiers(in Chinese),2001,8(1):259~266
[15]张先康,李松林,王夫运等.青藏高原东北缘、鄂尔多斯和唐山的地壳结构差异———深地震测深的结果.地震地质,2003,25(1):52~60Zhang X K,Li S L,Wang F Y,et al.Differences of crustalstructures in northeastern edge of Tibet plateau,Ordos and Tangshanearthquake region in North China—results of deep seismic sounding.Seismology and Geology(in Chinese),2003,25(1):52~60
[16]孙建中,樊祺诚,陈文寄.琼北地区第四纪火山活动的研究.见:丁原章等编.海南岛北部地震研究文集.北京:地震出版社,1988.17~25Sun J Z,Fan Q C,Chen W J.The Quartary active volcano researchin North Qiong area.In:Ding Y Z eds.Collected Works ofEarthquake Research in North Hainan Island(in Chinese).Beijing:Seismological Press,1988.17~25
[17]廖其林,王振明,王屏路等.福州-泉州-汕头地区地壳结构的爆破地震研究.地球物理学报,1988,31(3):270~280Liao Q L,Wang Z M,Wang P L,et al.Explosion seismic study ofthe crustal structure in Fuzhou-Quanzhou-Shantou region.Chinese J.Geophys.(in Chinese),1999,31(3):270~280
[18]尹周勋,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.地球物理学报,1999,42(3):383~392Yin Z X,Lai M H,Xiong S B,et al.Crustal structure and velocitydistribution from deep seismic sounding along the profile of Lianxian-Boluo-Gangkou in South China.Chinese J.Geophys.(in Chinese),1999,42(3):383~392
[19]熊绍柏,金东敏,孙克忠等.福建漳州地热田及邻近地区的地壳深部构造特征.地球物理学报,1991,34(1):55~63Xiong S B,Jin D M,Sun K Z,et al.Some characteristics of deepstructure of the Zhangzhou geothermal field and its neighbourhood inthe Fujian province.Chinese J.Geophys.(in Chinese),1991,34(1):55~63
[20]李志雄,赵文俊,刘光夏.1605年琼山大地震深部构造和应力状态研究.华南地震,2006,26(1):28~36Li Z X,Zhao W J,Liu G X.A study on deep crust structures andstress situation of the 1605 Qiongshan strong earthquake.SouthChina Journal of Seismology(in Chinese),2006,26(1):28~36
[21]丘学林.内海北部大陆边缘的深部地壳结果和构造意义.见:中国地球物理2004年会.西安:西安地图出版社,2004.1~3Qiu X L.The deep crustal structure and its tectonic significance inthe northern continental.In:Annual of the Chinese GeophysicalSociety,2004(in Chinese).Xi’an:Xi’an Cartographic PublishingHouse,2004.1~3
[2]林中洋,胡鸿翔,朱良保等.雷琼地区地壳结构的初步结果.见:丁原章等编.海南岛北部地震研究文集.北京:地震出版社,1988.127~139Lin Z Y,Hu H X,Zhu L B,et al.The primary results of crustalstructures in Leiqiong area.In:Ding Y Z eds.Collected Works ofEarthquake Research in North Hainan Island(in Chinese).Beijing:Seismological Press,1988.127~139
[3]章林云,王振明.琼东北地区人工地震测深研究.见:丁原章等编.海南岛北部地震研究文集.北京:地震出版社,1988.112~116Zhang L Y,Wang Z M.Study of DSS in Northeast Hainan Island.In:Ding Y Z eds.Collected Works of Earthquake Research in NorthHainan Island(in Chinese).Beijing:Seismological Press,1988.112~116
[4]彭承光,张福来,王业兴等.广东、海南地震构造.马杏垣主编.中国岩石圈动力学地图集.北京:中国地图出版社,1989.46Peng C G,Zhang F L,Wang Y X,et al.Seismotectonics ofGuangdong and Hainan provinces.In:Ma X Y ed.LithosphericDynamics Atlas of China(in Chinese).Beijing:China CartographicPublishing House,1989.46
[5]嘉世旭,刘昌铨.华北地区人工地震测深震相与地壳结构研究.地震地质,1995,17(2):97~105Jia S X,Liu C Q.Study on the seismic phase of DSS in NorthChina.Seismology and Geology(in Chinese),1995,17(2):97~105
[6]Vidale J.Finite-difference calculation of travel-times.Bull Seism.Soc.Am.,1988,78:2062~2076
[7]Hole J A.Nonlinear high_resolution three_dimensional seismic traveltime tomography.J.Geophys.Res.,1992,97:456~501
[8]段永红,赖晓岭,张先康等.二、三维有限差分走时层析成像.华北地震科学,1999,17(4):53~60Duan Y H,Lai X L,Zhang X K,et al.2-D and 3-D finitedifference seismic traveltime tomography.Earthquake Science inNorth China(in Chinese),1999,17(4):53~60
[9]陈,陈运泰.晋中南地区地壳结构的初步研究.地球物理学报,1974,17(3):186~199Chen Y,Chen Y T.The primary study of crustal structures in centraland southern region of Shanxi Province.Chinese J.Geophys.(inChinese),1974,17(3):186~199
[10]杨卓欣,张文彬,杨键.华北北部结晶基底-Pg波时间项法分析.见:河南地球物理科学论文集.郑州:河南科学技术出版社,1993.93~96Yang Z X,Zhang W B,Yang J.The crystalline basement innorthern area of North China—Pg wave time term analysis.In:Collected Works of Geophysics in Henan(in Chinese).Zhengzhou:Henan Science&Technology Press,1993.93~96
[11]Cerveny V.Ray theoretical seismograms for laterally inhomogenousstructures.Geophys.,1979,46:335~342
[12]嘉世旭,刘昌铨.动力学射线追踪方法及其在二维非均匀介质理论地震图计算中的应用.见:国家地震局科技司编.中国大陆深部构造的研究与进展.北京:地质出版社,1988.279~287Jia S X,Liu C Q.Dynamic ray tracing and its application to thecomputation of synthetic seismograms in 2-D heterogeneous medium.In:Development in the Research of Deep Structures of China’sContinent(in Chinese).Beijing:Geological Publishing House,1988.279~287
[13]地质矿产部地球物理地球化学勘查研究所,地质矿产部区域重力方法技术中心.1:400万中国布格重力异常图.地质矿产部,1989The Institute of Geophysical and Geochemical Exploration and theTechnical Center of Regional Gravity Survey.The Bouguer gravityanomaly map of China on the scale of 1:4000000(in Chinese).Ministry of Geology and Mineral Resources,1989
[14]嘉世旭,张先康,方盛明.华北裂陷盆地不同块体地壳结构及演化研究.地学前缘,2001,8(2):259~266Jia S X,Zhang X K,Fang S M.Research on the crustal structureand evolution of different blocks in North China rift-depression basin.Earth Science Frontiers(in Chinese),2001,8(1):259~266
[15]张先康,李松林,王夫运等.青藏高原东北缘、鄂尔多斯和唐山的地壳结构差异———深地震测深的结果.地震地质,2003,25(1):52~60Zhang X K,Li S L,Wang F Y,et al.Differences of crustalstructures in northeastern edge of Tibet plateau,Ordos and Tangshanearthquake region in North China—results of deep seismic sounding.Seismology and Geology(in Chinese),2003,25(1):52~60
[16]孙建中,樊祺诚,陈文寄.琼北地区第四纪火山活动的研究.见:丁原章等编.海南岛北部地震研究文集.北京:地震出版社,1988.17~25Sun J Z,Fan Q C,Chen W J.The Quartary active volcano researchin North Qiong area.In:Ding Y Z eds.Collected Works ofEarthquake Research in North Hainan Island(in Chinese).Beijing:Seismological Press,1988.17~25
[17]廖其林,王振明,王屏路等.福州-泉州-汕头地区地壳结构的爆破地震研究.地球物理学报,1988,31(3):270~280Liao Q L,Wang Z M,Wang P L,et al.Explosion seismic study ofthe crustal structure in Fuzhou-Quanzhou-Shantou region.Chinese J.Geophys.(in Chinese),1999,31(3):270~280
[18]尹周勋,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.地球物理学报,1999,42(3):383~392Yin Z X,Lai M H,Xiong S B,et al.Crustal structure and velocitydistribution from deep seismic sounding along the profile of Lianxian-Boluo-Gangkou in South China.Chinese J.Geophys.(in Chinese),1999,42(3):383~392
[19]熊绍柏,金东敏,孙克忠等.福建漳州地热田及邻近地区的地壳深部构造特征.地球物理学报,1991,34(1):55~63Xiong S B,Jin D M,Sun K Z,et al.Some characteristics of deepstructure of the Zhangzhou geothermal field and its neighbourhood inthe Fujian province.Chinese J.Geophys.(in Chinese),1991,34(1):55~63
[20]李志雄,赵文俊,刘光夏.1605年琼山大地震深部构造和应力状态研究.华南地震,2006,26(1):28~36Li Z X,Zhao W J,Liu G X.A study on deep crust structures andstress situation of the 1605 Qiongshan strong earthquake.SouthChina Journal of Seismology(in Chinese),2006,26(1):28~36
[21]丘学林.内海北部大陆边缘的深部地壳结果和构造意义.见:中国地球物理2004年会.西安:西安地图出版社,2004.1~3Qiu X L.The deep crustal structure and its tectonic significance inthe northern continental.In:Annual of the Chinese GeophysicalSociety,2004(in Chinese).Xi’an:Xi’an Cartographic PublishingHouse,2004.1~3
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