复杂地质结构OBS地震剖面震相识别方法
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摘要
震相识别对获取深部速度结构至关重要.横穿加瓜海脊的T1测线东段,地形高差达3km,沉积厚度相差约2km,沉积基底变化复杂,对海底地震仪(OBS)地震剖面的震相识别增加了难度.本文以该测线东段OBS数据为例,采用地形校正、基底校正、多次波识别、正演模拟、走时投影等多种手段,开展了复杂构造的OBS震相识别研究,获得了测线下方深部速度结构模型.结果表明,采用的方法对复杂地质结构下OBS震相识别是行之有效的,相比传统的方法提供了更多且准确的震相走时信息,获得的速度模型更加可靠.
Phase identification plays a critical role in modeling the deep velocity structure.The geological structure is complex along the east part of Line T1 across the Gagua Ridge since its topography of sea bottom reaching 3 km in height and the sediment arriving at about 2 km in thickness.As a result,it is difficult to identify seismic phase in Ocean Bottom Seismometer(OBS)seismic record sections.In this paper,we adopt many methods including topographic correction,basement correction,multiple wave identification,forward modeling and travel time projection,and build a set of measures about phase identification for the complex geologic structure taking the OBS data along the east part of Line T1 as examples.The results show that these technical measures of phase identification are useful and effective for OBS data along the complex geological structure,which offers much more accurate travel-time information andobtains more reliable deep velocity structure.
Phase identification plays a critical role in modeling the deep velocity structure.The geological structure is complex along the east part of Line T1 across the Gagua Ridge since its topography of sea bottom reaching 3 km in height and the sediment arriving at about 2 km in thickness.As a result,it is difficult to identify seismic phase in Ocean Bottom Seismometer(OBS)seismic record sections.In this paper,we adopt many methods including topographic correction,basement correction,multiple wave identification,forward modeling and travel time projection,and build a set of measures about phase identification for the complex geologic structure taking the OBS data along the east part of Line T1 as examples.The results show that these technical measures of phase identification are useful and effective for OBS data along the complex geological structure,which offers much more accurate travel-time information andobtains more reliable deep velocity structure.
引文
Ao W,Zhao M H,Qiu X L,et al.2010.The correction of shot and OBS position in the 3Dseismic experiment of the SW Indian Ocean Ridge.Chinese Journal of Geophysics(in Chinese),53(12):2982-2991,doi:10.3969/j.issn.0001-5733.2010.12.022．
Cohen J K,Stockwell J W Jr.1995.The SU User’s Manual.Colorado School of Mines,1-40．
Eakin D H,Mcintosh K D,Van Avendonk H J A,et al.2015.New geophysical constraints on a failed subduction initiation:the structure and potential evolution of the Gagua Ridge and Huatung Basin.Geochemistry,Geophysics,Geosystems,16(2):380-400．
Gou F J,Ito A,Kodaira S,et al.2006.Confirming sharp bending of the Pacific plate in the northern Japan trench subduction zone by applying a traveltime mapping method.Physics of the Earth and Planetary Interiors,157(1-2):72-85．
Han X L.2005.Study of characteristics and suppression of highprecision seismic exploration for period-varying ghost and reverberation in paralic zone[Master′s thesis](in Chinese).Qingdao:Ocean University of China．
Kashubin S N,Petrov O V,Rybalka A V,et al.2017.Earth′s crust model of the South-Okhotsk Basin by wide-angle OBSdata.Tectonophysics,710-711:37-55．
LüC C,Hao T Y,Qiu X L,et al.2011.Deep crustal structure of the northern part of southwest Sub-Basin,South China Sea,from ocean bottom seismic data.ChineseJournalofGeophysics,54(6):1022-1032．
Li C F,Zhou Z Y,Li J B,et al.2007.Precollisional tectonics and terrain amalgamation offshore southern Taiwan:Characterizations from reflection seismic and potential field data.Science in China Series D:Earth Sciences,50(6):897-908．
Liu L H,Hao T Y,LüC C,et al.2015.Crustal structure of Bohai Sea and adjacent area(North China)from two onshoreoffshore wide-angle seismic survey lines.Journal of Asian Earth Sciences,98:457-469．
Liu L H,LüC C,Hao T Y,et al.2012.Data processing methods of OBS and its development tendency in detection of offshore oil and gas resources.ProgressinGeophysics(in Chinese),27(6):2673-2684．
Niu X W,Wei X D,Ruan A G,et al.2014.Comparison of inversion method of wide angle Ocean Bottom Seismometer profile:A case study of profile OBS973-2across Liyue bank in the South China Sea.Chinese Journal of Geophysics(in Chinese),57(8):2701-2712,doi:10.6038/cjg20140828．
Qiu X L,Ye S Y,Wu S M,et al.2001.Crustal structure across the Xisha Trough,northwestern South China Sea.Tectonophysics,341(1-4):179-193．
Ruan A G,Wei X D,Niu X W,et al.2016.Crustal structure and fracture zone in the Central Basin of the South China Sea from wide angle seismic experiments using OBS.Tectonophysics,688:1-10．
Wang J,Zhao M H,Zhang J Z,et al.2017.The importance of seafloor topographic correction in identifying and picking seismic phases of OBS.Journal of Tropical Oceanography(in Chinese),36(5):93-100．
Wang Q,Qiu X L,Zhao M H,et al.2016.Analysis and processing on abnormal OBS data in the South China Sea.Chinese Journal of Geophysics(in Chinese),59(3):1102-1112,doi:10.6038/cjg20160330．
Wessel P,Smith W H F.1998.New,improved version of generic mapping tools released.Eos,79(47):579．
Xia S H,Ao W,Zhao M H,et al.2011.Corrections and analysis of wide angle seismic data from the sea.Marine Science Bulletin(in Chinese),30(5):487-491．
Xue Y R,Yang J,Ma J T,et al.2016.Amplitude-preserving nonlinear adaptive multiple attenuation using the high-order sparse Radon transform.Journal of Geophysics and Engineering,13(3):207-219．
Zelt C A,Smith R B.1992.Seismic travel-time inversion for 2-Dcrustal velocity structure.Geophysical Journal International,108(1):16-34．
Zhang J Z,Zhao M H,Qiu X L,et al.2013.Seismic phases from the Moho and its implication on the ultraslow spreading ridge．Acta Oceanologica Sinica,32(12):75-86．
Zhu J J,Kopp H,Flueh E R,et al.2010.Crustal structure of the central Costa Rica subduction zone:Implications for basal erosion from seismic wide-angle data.Geophysical Journal International,178(2):1112-1131．
敖威，赵明辉，丘学林等．2010．西南印度洋中脊三维地震探测中炮点与海底地震仪的位置校正．地球物理学报，53(12):2982-2991,doi:10.3969/j.issn.0001-5733.2010.12.022．
韩晓丽．2005．滩浅海高精度地震勘探变周期虚反射和海底鸣震特征及压制研究[硕士论文]．青岛：中国海洋大学．
李春峰，周祖翼，李家彪等．2007．台湾岛南部海域的前碰撞构造地球物理特征．中国科学：地球科学，37(5):649-659．
刘丽华，吕川川，郝天珧等．2012．海底地震仪数据处理方法及其在海洋油气资源探测中的发展趋势．地球物理学进展，27(6):2673-2684．
牛雄伟，卫小冬，阮爱国等．2014．海底广角地震剖面反演方法对比---以南海礼乐滩OBS剖面为例．地球物理学报，57(8):2701-2712,doi:10.6038/cjg20140828．
王建，赵明辉，张佳政等．2017．海底地形校正在正确拾取OBS震相中的重要作用．热带海洋学报，36(5):93-100．
王强，丘学林，赵明辉等．2016．南海海底地震仪异常数据的分析和处理．地球物理学报，59(3):1102-1112,doi:10.6038/cjg20160330．
夏少红，敖威，赵明辉等．2011．海洋广角地震数据校正方法探讨．海洋通报，30(5):487-491.
Cohen J K,Stockwell J W Jr.1995.The SU User’s Manual.Colorado School of Mines,1-40．
Eakin D H,Mcintosh K D,Van Avendonk H J A,et al.2015.New geophysical constraints on a failed subduction initiation:the structure and potential evolution of the Gagua Ridge and Huatung Basin.Geochemistry,Geophysics,Geosystems,16(2):380-400．
Gou F J,Ito A,Kodaira S,et al.2006.Confirming sharp bending of the Pacific plate in the northern Japan trench subduction zone by applying a traveltime mapping method.Physics of the Earth and Planetary Interiors,157(1-2):72-85．
Han X L.2005.Study of characteristics and suppression of highprecision seismic exploration for period-varying ghost and reverberation in paralic zone[Master′s thesis](in Chinese).Qingdao:Ocean University of China．
Kashubin S N,Petrov O V,Rybalka A V,et al.2017.Earth′s crust model of the South-Okhotsk Basin by wide-angle OBSdata.Tectonophysics,710-711:37-55．
LüC C,Hao T Y,Qiu X L,et al.2011.Deep crustal structure of the northern part of southwest Sub-Basin,South China Sea,from ocean bottom seismic data.ChineseJournalofGeophysics,54(6):1022-1032．
Li C F,Zhou Z Y,Li J B,et al.2007.Precollisional tectonics and terrain amalgamation offshore southern Taiwan:Characterizations from reflection seismic and potential field data.Science in China Series D:Earth Sciences,50(6):897-908．
Liu L H,Hao T Y,LüC C,et al.2015.Crustal structure of Bohai Sea and adjacent area(North China)from two onshoreoffshore wide-angle seismic survey lines.Journal of Asian Earth Sciences,98:457-469．
Liu L H,LüC C,Hao T Y,et al.2012.Data processing methods of OBS and its development tendency in detection of offshore oil and gas resources.ProgressinGeophysics(in Chinese),27(6):2673-2684．
Niu X W,Wei X D,Ruan A G,et al.2014.Comparison of inversion method of wide angle Ocean Bottom Seismometer profile:A case study of profile OBS973-2across Liyue bank in the South China Sea.Chinese Journal of Geophysics(in Chinese),57(8):2701-2712,doi:10.6038/cjg20140828．
Qiu X L,Ye S Y,Wu S M,et al.2001.Crustal structure across the Xisha Trough,northwestern South China Sea.Tectonophysics,341(1-4):179-193．
Ruan A G,Wei X D,Niu X W,et al.2016.Crustal structure and fracture zone in the Central Basin of the South China Sea from wide angle seismic experiments using OBS.Tectonophysics,688:1-10．
Wang J,Zhao M H,Zhang J Z,et al.2017.The importance of seafloor topographic correction in identifying and picking seismic phases of OBS.Journal of Tropical Oceanography(in Chinese),36(5):93-100．
Wang Q,Qiu X L,Zhao M H,et al.2016.Analysis and processing on abnormal OBS data in the South China Sea.Chinese Journal of Geophysics(in Chinese),59(3):1102-1112,doi:10.6038/cjg20160330．
Wessel P,Smith W H F.1998.New,improved version of generic mapping tools released.Eos,79(47):579．
Xia S H,Ao W,Zhao M H,et al.2011.Corrections and analysis of wide angle seismic data from the sea.Marine Science Bulletin(in Chinese),30(5):487-491．
Xue Y R,Yang J,Ma J T,et al.2016.Amplitude-preserving nonlinear adaptive multiple attenuation using the high-order sparse Radon transform.Journal of Geophysics and Engineering,13(3):207-219．
Zelt C A,Smith R B.1992.Seismic travel-time inversion for 2-Dcrustal velocity structure.Geophysical Journal International,108(1):16-34．
Zhang J Z,Zhao M H,Qiu X L,et al.2013.Seismic phases from the Moho and its implication on the ultraslow spreading ridge．Acta Oceanologica Sinica,32(12):75-86．
Zhu J J,Kopp H,Flueh E R,et al.2010.Crustal structure of the central Costa Rica subduction zone:Implications for basal erosion from seismic wide-angle data.Geophysical Journal International,178(2):1112-1131．
敖威，赵明辉，丘学林等．2010．西南印度洋中脊三维地震探测中炮点与海底地震仪的位置校正．地球物理学报，53(12):2982-2991,doi:10.3969/j.issn.0001-5733.2010.12.022．
韩晓丽．2005．滩浅海高精度地震勘探变周期虚反射和海底鸣震特征及压制研究[硕士论文]．青岛：中国海洋大学．
李春峰，周祖翼，李家彪等．2007．台湾岛南部海域的前碰撞构造地球物理特征．中国科学：地球科学，37(5):649-659．
刘丽华，吕川川，郝天珧等．2012．海底地震仪数据处理方法及其在海洋油气资源探测中的发展趋势．地球物理学进展，27(6):2673-2684．
牛雄伟，卫小冬，阮爱国等．2014．海底广角地震剖面反演方法对比---以南海礼乐滩OBS剖面为例．地球物理学报，57(8):2701-2712,doi:10.6038/cjg20140828．
王建，赵明辉，张佳政等．2017．海底地形校正在正确拾取OBS震相中的重要作用．热带海洋学报，36(5):93-100．
王强，丘学林，赵明辉等．2016．南海海底地震仪异常数据的分析和处理．地球物理学报，59(3):1102-1112,doi:10.6038/cjg20160330．
夏少红，敖威，赵明辉等．2011．海洋广角地震数据校正方法探讨．海洋通报，30(5):487-491.
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