Inversion of the Physical Properties of the Seabed Using Chirp Sub-Bottom Data in Mud Volcanoes Field of the Southwest of Dongsha Islands
-
摘要: Chirp浅剖图像可以显示东沙群岛西南海域存在泥火山.通过基于Chirp浅剖记录数据的反演方法研究,定量地分析泥火山区海底物性参数.首先由Chirp浅剖记录的反射振幅计算了海底反射系数,结果表明泥火山区的反射变化很大(0.1~0.8).对于海底弱反射(<0.45) 区域,用Schock-Stoll模型以及物理参数间的经验公式反演海底浅表层物理性质参数(速度、密度、孔隙度等参数);对于海底强反射(>0.45) 区域,用Gardner经验公式反演海底浅表层物理性质参数.反演结果表明研究区海底物性变化大,声速最高达5 237 m/s,密度最大为2.673 g/cm3.反演的物性参数与实验室测量值吻合度较高.Chirp浅剖数据反演是一种有效可行的遥测海底声学参数方法.Abstract: Mud volcanoes are imaged from Chirp sub-bottom profiles across the southwest of Dongsha Islands. In order to quantify the physical properties of the seabed, this paper studies the inversion of the Chirp sub-bottom data. First, reflection coefficients of the seabed are calculated, the results show that the reflection magnitudes of the seabed vary from 0.1-0.8. The physical properties (velocity, density, porosity etc.) of the seabed are obtained by the Schock-Stoll Model and the empirical relationships among the physical properties for the part reflection coefficients smaller than 0.45, and the physical properties (velocity and density) of the seabed are obtained by Gardner empirical equation for the part reflection coefficients larger than 0.45. Results of the inversion show that the physical properties vary greatly with the maximum velocity of 5 237 m/s and density of 2.673 g/cm3. The Chirp data-based physical properties highly coincide with the laboratory measurements for sampled sediments, thus provides us a remote acoustic method for estimating the physical properties of the seabed.
-
表 1 SO95航次沉积采样声学实测数据*
Table 1. Measurements of the samples of the sites in SO95
站位 水深(m) Vp(m/s) 密度(g/cm3) 孔隙度(%) 17929 371 1 552 1.74 54.1 17930 629 1 633 1.56 64.7 17931 1 005 1 551 1.48 69.2 17932 1 365 1 447 1.33 70.8 17934 2 665 1 433 1.41 73.3 17935 3 143 1 631 1.40 73.5 17936 3 809 1 493 1.35 78.2 17937 3 428 1 535 1.40 73.2 17938 2 835 1 468 1.42 71.8 17939 2 473 1 506 1.37 74.1 17940 1 728 1 531 1.36 75.3 注:*数据由中国科学院南海海洋研究所卢博提供. -
[1] Anstey, N.A., 1977.Seismic Interpretation:The Physical Aspects.Boston:Int.Human Rights Dev.Corp., Boston. [2] Barnes, P.M., Lamarche, G., Bialas, J., et al., 2010.Tectonic and Geological Framework for Gas Hydrates and Cold Seeps on the Hikurangi Subduction Margin, New Zealand.Marine Geology, 272(1-2):26-48.doi: 10.1016/j.margeo.2009.03.012 [3] Biot, M.A., 1956.Theory of Propagation of Elastic Waves in a Fluid-Saturated Porous Solid.Ⅱ.Higher High-Frequency Range.The Journal of the Acoustic Society of America, 28(2):172-191.doi: 10.1121/1.1908241 [4] Biot, M.A., 1962.Mechanics of Deformation and Acoustic Propagation in Porous Media.J.Appl.Phys., 33(4):1482-1498.doi: 10.1063/1.1728759 [5] Breslau, L.R., 1964.Sound Reflection from the Sea Floor and Its Geological Significance.Massachusetts Institute of Technology, Boston. [6] Bull, J.M., Quinn, R., Dix, J.K., 1998.Reflection Coefficient Calculation from Marine High Resolution Seismic Reflection (Chirp) Data and Application to an Archaeological Case Study.Marine Geophysical Researches, 20(1):1-11.doi: 10.1023/A:1004373106696 [7] Chen, J., Yan, P., Wang, Y.L., et al., 2012.Choice of Parameters for Biot-Stoll Model-based Inversion of Sound Velocity of Seafloor Sediments in the Southern South China Sea.Journal of Tropical Oceanography, 31(1):50-54 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-RDHY201201008.htm [8] Chen, Z., Yang, H.P., Huang, Q.Y., et al., Characteristics of Cold Seeps and Structures of Chemoauto-Synthesis-Based Communities in Seep Sediments.Journal of Tropical Oceanography, 26(6):73-82 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-RDHY200706012.htm [9] Hamilton, E.L., Bachman R.T., 1982.Sound Velocity and Related Properties of Marine Sediments.Journal of the Acoustical Society of America, 72(1):1891-1904.doi: 10.1121/1.388539 [10] Kallweit, R.S., Wood, L.C., 1982.The Limits of Resolution of Zero-Phase Wavelets.Geophysics, 47(7):1035-1046.doi: 10.1190/1.1441367 [11] Lambe, T.W., Whiteman, R.V., 1969.Soil Mechanics.New York:Wiley, New York. [12] Li, L., Lei, X., Zhang, X., et al., 2013.Gas Hydrate and Associated Free Gas in the Dongsha Area of Northern South China Sea.Marine and Petroleum Geology, 39(1):92-101.doi: 10.1016/j.marpetgeo.2012.09.007 [13] Lu, B., Liu, Q., 2008.Grain and Pore Factors in Acoustic Response of Seafloor Sediments.Journal of Tropical Oceanography, 27(3):23-29 (in Chinese with English abstract). doi: 10.1080/10641191003780724?journalCode=umgt20 [14] Lu, J.M., Wang, Y.G., 2009.The Principles of Seismic Prospecting.China Petroleum Press, Beijing, 141 (in Chinese). [15] Lüdmann, T., Wong, H.K., Wang, P.X., 2001.Plio-Quaternary Sedimentation Processes and Neotectonics of the Northern Continental Margin of the South China Sea.Marine Geology, 172(3-4):331-358.doi: 10.1016/S0025-3227(00)00129-8 [16] Milkov, A.V., 2000.Worldwide Distribution of Submarine Mud Volcanoes and Associated Gas Hydrates.Marine Geology, 167(1-2):29-42.doi: 10.1016/S0025-3227(00)00022-0 [17] Quinn, R., Bull, J.M., Dix, J.K., 1998.Optimal Processing of Marine High-Resolution Seismic Reflection (Chirp) Data.Marine Geophysical Researches, 20(1):13-20.doi: 10.1023/A:1004349805280 [18] Schock, S.G., 2004a.A Method for Estimating the Physical and Acoustic Properties of the Seabed Using Chirp Sonar Data., IEEE Journal of Oceanic Engineering., 29(4):1200-1217.doi: 10.1109/JOE.2004.841421 [19] Schock, S.G., 2004b.Remote Sediment Estimates of Physical and Acoustic Properties in the South China Sea Using Chirp Sonar Data and the Biot Model.IEEE Journal of Oceanic Engineering, 29(4):1218-1230.doi: 10.1109/JOE.2004.842253 [20] Schock, S.G., Lester, R.L.LeBlanc, Larry, A.M.ayer, 1989.Chirp Subbottom Profiler for Quantitative Sediment Analysis.Geophysics, 54(4):445-450.doi: 10.1190/1.1442670 [21] Spence, G.D., Minshull, T.A., Fink, C., 1995.Seismic Studies of Methane Gas Hydrate, Offshore Vancouver Island.In:Carson, B., Westbrook, G.K., Musgrave, R.J., eds., Proc.ODP., Sci.Results 146 (Pt 1), College Station, Tx (Ocean Drilling Program), 163-174. [22] Stoll, R., 1977.Acoustic Waves in Ocean Sediments.Geophysics, 42(4):715-725.doi: 10.1190/1.1440741 [23] Tian, X., Xu, Y., Zhang, J., et al., 2012.Streptomyces Oceani Sp.Nov., a New Obligate Marine Actinomycete Isolated from a Deep-Sea Sample of Seep Authigenic Carbonate Nodule in South China Sea.Antonie van Leeuwenhoek., 102(2):335-343. doi: 10.1007/s10482-012-9743-x [24] Wang, S.H., Yan, W., Chen, Z., 2010.Advance in Research of the Calcium Isotope Tracer in Cold Seep System of Sea Floor.Geoscience, 24(3):589-597 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-XDDZ201003025.htm [25] Warner, M., 1990.Absolute Reflection Coefficients from Deep Seismic Reflections.Tectonophysics, 173(1-4):15-2.doi: 10.1016/0040-1951(90)90199-I [26] Wu, S., Zhang, G., Huang, Y., 2005.Gas Hydrate Occurrence on the Continental Slope of the Northern South China Sea.Marine and Petroleum Geology, 22(3):403-412.doi: 10.1016/j.marpetgeo.2004.11.006 [27] Yan, P., Wang, Y.L., Zheng, H.B., et al., 2014 Geophysical Features of Mud Volcanoes in the Waters Southwest of the Dongsha Islands.Acta Oceanologica Sinica, 36(7):142-148 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-SEAC201407016.htm [28] Zheng, H.B., Yan, P., Chen, J., et al., 2012.Seabed Sediment Classification in the Northern South China Sea Using Inversion Method.Applied Ocean Research, 39:131-136.doi: 10.1016/j.apor.2012.11.002 [29] 陈静, 阎贫, 王彦林, 等, 2012.基于Biot-Stoll模型声速反演中的参数选择——以南海南部沉积物为例.热带海洋学报, 31(1): 50-54. http://www.cnki.com.cn/Article/CJFDTOTAL-RDHY201201008.htm [30] 陈忠, 杨华平, 黄奇瑜, 等, 2007.海底甲烷冷泉特征与冷泉生态系统的群落结构.热带海洋学报, 26(6): 73-82. http://www.cnki.com.cn/Article/CJFDTOTAL-RDHY200706012.htm [31] 卢博, 刘强, 2008.海底沉积物声学响应中的颗粒与孔隙因素.热带海洋学报, 27(3): 23-29. http://www.cnki.com.cn/Article/CJFDTOTAL-RDHY200803006.htm [32] 陆基孟, 王永刚, 2009.地震勘探原理(第三版).北京:中国石油出版社, 141. [33] 王淑红, 颜文, 陈忠, 2010.海底冷泉系统中的钙同位素示踪研究进展.现代地质, 24(3): 589-597. http://www.cnki.com.cn/Article/CJFDTOTAL-XDDZ201003025.htm [34] 阎贫, 王彦林, 郑洪波, 等, 2014.东沙群岛西南海区泥火山的地球物理特征.海洋学报, 36(7): 142-148. http://www.cnki.com.cn/Article/CJFDTOTAL-SEAC201407016.htm