广角地震速度结构反演中的不确定性分析*

doi:10.11978/2015132

摘要/Abstract

摘要： 海底地震仪(ocean bottom seismometer, OBS)广角地震探测是研究海洋深部精细壳幔结构的重要地球物理手段, 其主要原理是利用广角折射/反射震相信息来反演地壳深部结构, 从而为深入认识海底构造特征提供最为基础的地震学信息。文章基于地震层析成像结构反演的基本原理, 针对OBS广角地震速度结构反演中可能存在的一些不确定性因素, 用Tomo2D软件构建了不同的理论模型和数据体, 对初始模型中沉积层的变化是如何影响整个地壳速度结构的反演结果、不同台站间距所构建的数据体对下地壳高速层分辨精度的控制影响以及不同数据体在分辨深部异常体的有效性等方面进行了分析研究, 以此深入了解OBS广角地震速度结构反演中的不确定性因素。研究结果显示, 地壳深部较厚(大于4km)的高速层能够被很好地反演出来, 而较薄(小于2km)的高速层虽能够识别, 但其形态规模恢复得较差; 初始模型中沉积层速度结构的失真度影响着高速层的识别, 沉积层失真度越大, 对高速层的恢复越差; 地壳内部存在低速层对反演高速层的规模有较为明显的影响, 但低速层的厚度变化对其影响不大; 对于文中10km台站间距的模型, 能够识别的速度异常体规模在水平方向上最小约为5km, 在纵向上最小约为3km, 而20km和30km台站间距的模型最小能够识别的速度异常体规模为水平向10km、纵向3km。

关键词: 海底地震仪(OBS), 广角地震, 高速层, 速度结构反演, 南海

Abstract: Ocean bottom seismometer (OBS) wide-angle seismic exploration is an important geophysical method to obtain elaborate crust-mantle structure of deep sea. The main theory is to invert the deep crustal structure by refraction and reflection seismic phase and to provide basal seismic information for studying crust structural features. Based on the principle of seismic tomography structure inversion, we aimed at the uncertainty of velocity structure inversion in OBS wide-angle seismic experiment in this study. Several synthetic models and data were built by Tomo2D to study issues such as how different sedimentary layers may influence the inversion result of whole crust velocity structure, how the OBS space may influence the resolving accuracy of high velocity layer (HVL) in lower crust and the effectiveness of identifying the deep crust anomalous bodies. Our results show that the HVL thicker than 4 km can be well inverted and the thinner HVL (<2 km) is poorly inverted for its scale and shape. The deviation of sedimentary thickness in initial model can influence how to identify HVL; the larger deviation corresponds to worse identification. The low-velocity layer within the crust has significant impact on inverting the scale of HVL in lower crust, but the thickness of the low-velocity layer is insignificant. The smallest scale of velocity anomalous body that can be identified is 5 km in the horizontal and 3 km in the vertical when the OBS space is 10 km; and they are 10 km in the horizontal and 3 km in the vertical when the OBS space is 20 km and 30 km.

Key words: ocean bottom seismometer, wide-angle seismic, high velocity layer, velocity structure inversion, South China Sea

陈金虎, 夏少红, 曹敬贺, 万奎元, 丘学林. 广角地震速度结构反演中的不确定性分析^*[J]. 热带海洋学报, 2016, 35(5): 75-87.

CHEN Jinhu, XIA Shaohong, CAO Jinghe, WAN Kuiyuan, QIU Xuelin. Analysis on uncertainty in velocity structure inversion in wide-angle seismic experiments[J]. Journal of Tropical Oceanography, 2016, 35(5): 75-87.

参考文献

1 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[J]. 地球物理学报, 53(12): 2982-2991. AO WEI, ZHAO MINGHUI, QIU XUELIN, et al, 2010. The correction of shot and OBS position in the 3D seismic experiment of the SW Indian Ocean Ridge[J]. Chinese Journal of Geophysics, 53(12): 2982-2991 (in Chinese).
2 曹敬贺, 夏少红, 孙金龙, 等, 2012. 珠江口外潜在强震区海陆地震联测的初步结果[J]. 热带海洋学报, 31(3): 71-78. CAO JINGHE, XIA SHAOHONG, SUN JINLONG, et al, 2012. Preliminary results of onshore-offshore seismic experiments in a potential strong earthquake area off the Pearl River Estuary[J]. Journal of Tropical Oceanography, 31(3): 71-78 (in Chinese).
3 曹敬贺, 2014. 南海北部珠江口海域滨海断裂带的地震学特征研究[D]. 广州: 中国科学院南海海洋研究所: 1-115. CAO JINGHE, 2014. Research on seismology of littoral fault zone in the Pearl River estuary of northern South China Sea[D]. Guangzhou: South China Sea Institute of Oceanology, Chinese Academy of Sciences: 1-115 (in Chinese).
4 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[J]. 地球物理学报, 57(8): 2701-2712. NIU XIONGWEI, WEI XIAODONG, RUAN AIGUO, et al, 2014. Comparision of inversion method of wide angle Ocean Bottom Seismometer profile: a case study of profile OBS973-2 across Liyue bank in the South China Sea[J]. Chinese Journal of Geophysics, 57(8): 2701-2712 (in Chinese).
5 丘学林, 赵明辉, 叶春明, 等, 2003. 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, 27(4): 295-300. QIU XUELIN, ZHAO MINGHUI, YE CHUNMING, et al, 2003. Ocean bottom seismometer and onshore-offshore seismic experiment in northeastern South China Sea[J]. Geotectonica et Metallogenia, 27(4): 295-300 (in Chinese).
6 丘学林, 陈颙, 朱日祥, 等, 2007. 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, 52(4): 463-469. QIU XUELIN, CHEN YONG, ZHU RIXIANG, et al, 2007. The application of large volume airgun sources to the onshore-offshore seismic surveys: implication of the experimental results in northern South China Sea[J]. Chinese Science Bulletin, 52(4): 553-560.
7 丘学林, 赵明辉, 敖威, 等, 2011. 南海西南次海盆与南沙地块的OBS探测和地壳结构[J]. 地球物理学报, 54(12): 3117-3128. QIU XUELIN, ZHAO MINGHUI, AO WEI, et al, 2011. OBS survey and crustal structure of the Southwest Sub-basin and Nansha Block, South China Sea[J]. Chinese Journal of Geophysics, 54(12): 3117-3128 (in Chinese).
8 丘学林, 赵明辉, 徐辉龙, 等, 2012. 南海深地震探测的重要科学进程: 回顾和展望[J]. 热带海洋学报, 31(3): 1-9. QIU XUELIN, ZHAO MINGHUI, XU HUILONG, et al, 2012. Important processes of deep seismic surveys in the South China Sea: retrospection and expectation[J]. Journal of Tropical Oceanography, 31(3): 1-9 (in Chinese).
9 宋海斌, 郝天珧, 江为为, 1998. 南海北部张裂边缘的类型及其形成机制探讨[M]//陈颙. 寸丹集——庆贺刘光鼎院士工作50周年学术论文集. 北京: 科学出版社: 74-81.
10 卫小冬, 赵明辉, 阮爱国, 等, 2010. 南海中北部OBS2006-3地震剖面中横波的识别与应用[J]. 热带海洋学报, 29(5): 72-80. WEI XIAODONG, ZHAO MINGHUI, RUAN AIGUO, et al, 2010. Identification and application of shear waves along the profile OBS2006-3 in the mid-northern South China Sea[J]. Journal of Tropical Oceanography, 29(5): 72-80 (in Chinese )
11 卫小冬, 阮爱国, 赵明辉, 等, 2011. 穿越东沙隆起和潮汕坳陷的OBS广角地震剖面[J]. 地球物理学报, 54(12): 3325-3335. WEI XIAODONG, RUAN AIGUO, ZHAO MINGHUI, et al, 2011. A wide-angle OBS profile across Dongsha uplift and Chaoshan depression in the mid-northern South China Sea[J]. Chinese Journal of Geophysics, 54(12): 3325-3335 (in Chinese )
12 吴振利, 阮爱国, 李家彪, 等, 2008. 南海中北部地壳深部结构探测新进展[J]. 华南地震, 28(1): 21-28. WU ZHENLI, RUAN AIGUO, LI JIABIAO, et al, 2008. New progress of deep crust sounding in the mid-northern south China Sea using ocean bottom seismometers[J]. South China Journal of Seismology, 28(1): 21-28 (in Chinese )
13 吴振利, 李家彪, 阮爱国, 等, 2011. 南海西北次海盆地壳结构: 海底广角地震实验结果[J]. 中国科学: 地球科学, 41(10): 1463-1476. WU ZHENLI, LI JIABIAO, RUAN AIGUO, et al, 2011. Crustal structure of the northwestern sub-basin, South China Sea: results from a wide-angle seismic experiment[J]. Science China Earth Sciences, 55(1): 159-172. (in Chinese)
14 夏少红, 林伟, 陈建涛, 等, 2012. 海陆地震联测流动台站布设及信号分析[J]. 热带海洋学报, 31(3): 48-57. XIA SHAOHONG, LIN WEI, CHEN JIANTAO, et al, 2012. Layout of portable stations and signal analysis in an onshore-offshore seismic experiment[J]. Journal of Tropical Oceanography, 31(3): 48-57 (in Chinese ).
15 周祖翼, 李春峰, 2008. 大陆边缘构造与地球动力学[M]. 北京: 科学出版社: 49-53.
16 KORENAGA J, HOLBROOK W S, KENT G M, et al, 2000. Crustal structure of the southeast Greenland margin from joint refraction and reflection seismic tomography[J]. Journal of Geophysical Research: Solid Earth(1978-2012), 105(B9): 21591-21614.
17 NISSEN S, HAYES D, BUHL P, 1995. Deep penetration seismic soundings across the northern margin of the South China Sea[J]. Journal of Geophysical Research: Solid Earth, 100(B11): 22407-22433.
18 QIU XUELIN, YE SANYU, WU SHIMIN, et al, 2001. Crustal structure across the Xisha Trough, northwestern South China Sea[J]. Tectonophysics, 341(1-4): 179-193.
19 WANG T K, CHEN MINGKAI, LEE C S, et al, 2006. Seismic imaging of the transitional crust across the northeastern margin of the South China Sea[J]. Tectonophysics, 412(3-4): 237-254.
20 YAN PIN, ZHOU DI, LIU ZHAOSHU, 2001. A crustal structure profile across the northern continental margin of the South China Sea[J]. Tectonophysics, 338(1): 1-21.
21 ZHAO MINGHUI, QIU XUELIN, XIA SHAOHONG, et al, 2010. Seismic structure in the northeastern South China Sea: S-wave velocity and V p/ V s ratios derived from three-component OBS data[J]. Tectonophysics, 480(1-4): 183-197.

[1]	徐超, 龙丽娟, 李莎, 袁丽, 徐晓璐. 南海及其附属岛礁海洋科学考察历史资料系统整编3. 数据共享服务及应用[J]. 热带海洋学报, 2024, 43(5): 158-165.
[2]	徐超, 龙丽娟, 李莎, 何云开, 袁丽, 徐晓璐. 南海及其附属岛礁海洋科学考察历史资料系统整编1. 资料整编技术及应用[J]. 热带海洋学报, 2024, 43(5): 143-149.
[3]	徐超, 龙丽娟, 李莎, 徐晓璐, 袁丽. 南海及其附属岛礁海洋科学考察历史资料系统整编2. 数据治理技术与应用[J]. 热带海洋学报, 2024, 43(5): 150-157.
[4]	柳原, 柯志新, 李开枝, 谭烨辉, 梁竣策, 周伟华. 人类活动和沿岸流影响下的粤东近海浮游动物群落特征[J]. 热带海洋学报, 2024, 43(4): 98-111.
[5]	刘玓玓, 张喜洋, 孙富林, 王明壮, 谭飞, 施祺, 王冠, 杨红强. 南海海滩岩微生物群落结构和特定菌株对其成因机制的启示*[J]. 热带海洋学报, 2024, 43(4): 112-122.
[6]	江绿苗, 陈天然, 赵宽, 张婷, 许莉佳. 南海北部涠洲岛边缘珊瑚礁的生物侵蚀实验研究[J]. 热带海洋学报, 2024, 43(3): 155-165.
[7]	许莉佳, 廖芝衡, 陈辉, 王永智, 黄柏强, 林巧云, 甘健锋, 杨静. 南海北部珊瑚群落结构特征及其对海洋热浪事件的响应[J]. 热带海洋学报, 2024, 43(3): 58-71.
[8]	邱燕, 鞠东, 黄文凯, 王英民, 聂鑫. 南海中央海盆海底初始扩张时间的重新认定[J]. 热带海洋学报, 2024, 43(2): 154-165.
[9]	赵明辉, 袁野, 张佳政, 张翠梅, 高金尉, 王强, 孙珍, 程锦辉. 南海北部被动陆缘洋陆转换带张裂-破裂研究新进展[J]. 热带海洋学报, 2024, 43(2): 173-183.
[10]	黄谕, 王琳, 麦志茂, 李洁, 张偲. 南海热带岛礁生物土壤结皮中细菌的分离及其固砂特性初步研究[J]. 热带海洋学报, 2023, 42(6): 101-110.
[11]	王辰燕, 史敬文, 颜安南, 康亚茹, 王煜轩, 覃素丽, 韩民伟, 张瑞杰, 余克服. 有机磷酸酯在南海长棘海星中的生物富集特征及来源解析[J]. 热带海洋学报, 2023, 42(5): 30-37.
[12]	李牛, 邸鹏飞, 冯东, 陈多福. 冷泉渗漏对海洋沉积物氧化还原环境地球化学识别的影响——以南海东北部F站位活动冷泉为例^*[J]. 热带海洋学报, 2023, 42(5): 144-153.
[13]	张智晟, 谢玲玲, 李君益, 李强. 边缘海与开阔海中尺度涡生命周期演化规律对比分析: 以南海和黑潮延伸体为例[J]. 热带海洋学报, 2023, 42(4): 63-76.
[14]	杨磊, 温金辉, 王强, 罗希, 黄华明, 何云开, 陈举. 热带气旋影响吕宋海峡输运的研究进展与展望^*[J]. 热带海洋学报, 2023, 42(3): 40-51.
[15]	赵中贤, 孙珍, 毛云华, 张伙带. 南海北部陆缘不均匀伸展及脉动式构造升降史^*[J]. 热带海洋学报, 2023, 42(3): 96-115.

广角地震速度结构反演中的不确定性分析^*

Analysis on uncertainty in velocity structure inversion in wide-angle seismic experiments

PDF (PC)

赞

可视化

摘要/Abstract

引用本文

使用本文

参考文献

相关文章 15

Metrics

本文评价

推荐阅读 0