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Shear Wave Speed Dispersion Characteristics of Seafloor Sediments in the Northern South China Sea

Journal of Ocean University of China 2022年第1期21卷 91-100页

作者： kan guangming MENG Xiangmei WANG Jingqiang CAO Guolin LI Guanbao LIU Baohua ZHI Pengyao Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(QingdaoQingdao 266237China College of Earth Science and Engineering Shandong University of Science and TechnologyQingdao 266590China

To accurately characterize the shear wave speed dispersion of seafloor sediments in the northern South China Sea,five types of sediments including silty clay,clayey silt,sandy silt,silty sand,and clayey sand were selected,on which the measurements of the shear wave speed at 0.5-2.0 kHz and related physical properties were performed.Results reveal that the shear wave speed of sediments increases as the frequency increases,and the dispersion enhanced in the sediments in the order of silty clay,clayey silt,sandy silt,silty sand,and clayey sand,at a linear change rate of 0.727,0.787,3.32,4.893,and 6.967 m s−1 kHz−1,respectively.Through regression analysis,linear and logarithmic regression equations for the correlation between shear wave speed and frequency were established for each sediment type and the determination coefficients of regression equations indicate that the correlation is closer to a logarithmic relationship.The Grain-Shearing(GS)and Biot-Stoll models were used to calculate the shear wave speed dispersion of the five sediment types,and the comparison between theoretical prediction and measured results of shear wave speeds shows that the GS model can more accurately describe the shear wave speed dispersion characteristics of these sediments in the frequency band of 0.5-2.0 kHz.In the same band,the predictions obtained by using the Biot-Stoll model are significantly different from the measured data.

关键词： shear wave speed dispersion seafloor sediments Biot-Stoll model Grain-Shearing model South China Sea

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Sound velocity and related properties of seafloor sediments in the Bering Sea and Chukchi Sea

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Acta Oceanologica Sinica 2015年第5期34卷 75-80页

作者： MENG Xiangmei LI Guanbao HAN Guozhong kan guangming First Institute of Oceanography State Oceanic Administration Key Laboratory of Marine Sedimentology and Environmental Geology State Oceanic Administration

The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment sound velocity is one of the main parameters. On seven sediment cores collected from the Bering Sea and Chukchi Sea during the 5th Chinese National Arctic Research Expedition, sound velocity measurements were made at 35, 50, 100, 135, 150, 174, 200, and 250 kHz using eight separate pairs of ultrasonic transducers. The measured sound velocities range from 1 425.1 m/s to 1 606.4 m/s and are dispersive with the degrees of dispersion from 2.2% to 4.0% over a frequency range of 35-250 kHz. After the sound velocity measurements, the measurements of selected geotechnical properties and the Scanning Electron Microscopic observation of microstructure were also made on the sediment cores. The results show that the seafioor sediments are composed of silty sand, sandy silt, coarse silt, clayey silt, sand-silt-clay and silty clay. Aggregate and diatom debris is found in the seafloor sediments. Through comparative analysis of microphotographs and geotechnical properties, it is assumed that the large pore spaces between aggregates and the intraparticulate porosity of diatom debris increase the porosity of the seafioor sediments, and affect other geotechnical properties. The correlation analysis of sound velocity and geotechnical properties shows that the correlation of sound velocity with porosity and wet bulk density is extreme significant, while the correlation of sound velocity with clay content, mean grain size and organic content is not significant. The regression equations between porosity, wet bulk density and sound velocity based on best-fit polynomial are given.

关键词： Bering Sea Chukchi Sea sound velocity geotechnical properties microstructure

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Empirical Equations of P-Wave Velocity in the Shallow and Semi-Deep Sea Sediments from the South China Sea

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Journal of Ocean University of China 2021年第3期20卷 532-538页

作者： LI Guanbao HOU Zhengyu WANG Jingqiang kan guangming LIU Baohua Key Laboratory of Seafloor Sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Key Laboratory of Ocean and Marginal Sea Geology South China Sea Institute of OceanologyInnovation Academy of South China Sea Ecology and Environmental EngineeringChinese Academy of SciencesGuangzhou 510301China Key Laboratory of Science and Technology on Operational Oceanography Chinese Academy of SciencesGuangzhou 511458China State Key Laboratory of Acoustics Chinese Academy of SciencesBeijing 100190China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China National Deep Sea Center Ministry of Natural ResourcesQingdao 266237China

Three-hundred and thirty-one sediment cores,including six sediment types(clayey-and sandy-silt,silty-and sandy-clay,clayey-and silty-sand)were collected from the shallow and semi-deep seas of the South China Sea,and the P-wave velocities and physical properties of core sediments were measured under standard laboratory conditions.To eliminate the influence of environ-mental factors,the empirical sound speed ratio equations were established.Compared with several equations from literature,the po-rosity and wet bulk density empirical equations established in this paper agree well with Richardson and Briggs(2004)’s in-situ equations,which implies that our empirical equations can be used in the similar region of world’s oceans under certain conditions and will be useful in areas lacking first-hand P-wave speed data.However,the mean grain size equations established in this study,similar to the previous studies,have low accuracy,which may be due to the different particle arrangements and degrees of compac-tion in sediments.The results also show that for different sediment types,the equation based on all sediment data is in good agree-ment with the measured data in the study area,as there are both siliciclastic and carbonate sediments on the studied seabed.It is sug-gested that appropriate empirical equations should be selected according to sediment types and sedimentary environment in future works,and the empirical equation of porosity or the two-parameter equation of porosity and grain size should be preferred.

关键词： seafloor sediment geo-acoustic property sound speed empirical equation South China Sea

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Influence of Environmental Conditions on the Sound Velocity Ratio of Seafloor Surficial Sediment

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Journal of Ocean University of China 2021年第3期20卷 573-580页

作者： ZOU Dapeng ZENG Ziwen kan guangming LIU Wei XIAO Tibing State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment Guangdong University of TechnologyGuangzhou 510006China Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China

In this work,we investigated the influences of salinity,temperature,and hydrostatic pressure on the acoustics of seafloor surficial sediment by theoretically and experimentally analyzing the sound velocity ratio of the seafloor sediment to the bottom sea-water in typical environmental conditions.Temperature-and pressure-controlled experiments were conducted to examine the charac-teristics of the sound velocity ratio,the results of which agree with the theoretical analysis using the effective density fluid model.Of the three environmental factors considered,the sound velocity ratio was found to be sensitive to temperature and pressure but not to salinity,with the sound velocity ratio decreasing with temperature and hydrostatic pressure.With respect to surficial sediments,pore water plays a key role in the sound velocity ratio of sediment influenced by different environmental factors.The sound velocities of different types of sediments(sandy,silty,and clayey)change similarly with temperature,but change slightly differently with hydro-static pressure.The influence of environmental factors on the sound velocity ratio of seafloor sediment is independent of the detec-tion frequency.The results show that the sound velocity ratio can change up to 0.0008 per℃ when the temperature ranges from 2℃ to 25℃ and up to 0.00064MPa−1 when the seawater depth pressure ranges from 0MPa to 40MPa.

关键词： sound velocity ratio environmental factors seafloor sediment geoacoustics

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Joint elastic-electrical properties of sediments in the Yellow Sea

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Science China Earth Sciences 2012年第1期55卷 143-148页

作者： HAN TongCheng LIU BaoHua kan guangming MENG XiangMei DING ZhongJun The First Institute of Oceanography State Oceanic AdministrationQingdao 266061China Key Laboratory of Marine Sedimentology and Environmental Geology State Oceanic AdministrationQingdao 266061China

We measured in the laboratory compressional wave velocity and electrical resistivity on 434 sediment samples collected from the Yellow Sea to study the joint elastic-electrical properties of marine sediments. Porosity was found to reduce both elastic velocity and electrical resistivity of the marine sediments in a non-linear fashion; velocity showed an approximate linear increase with increasing logarithm of resistivity. Various effective medium models either implemented or developed were compared with the new dataset. The model results showed that the combined self-consistent approximation and differential effective medium model using critical porosity of 0.6 and 0.5 for velocity and resistivity respectively gave a reasonable description of the joint elastic-electrical behaviors of the marine sediments. The joint elastic-electrical properties of the marine sediments established would be used to estimate resistivity from measured velocity and vice versa, and could also be suitable for detection of gas hydrate or other suitable targets from joint seismic-resistivity surveys.

关键词：海洋沉积物电气性能弹性黄海电阻率测量有效介质模型纵波速度天然气水合物

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A backscattering model for a stratified seafloor

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Acta Oceanologica Sinica 2017年第7期36卷 56-65页

作者： YU Shengqi LIU Baohua YU Kaiben YANG Zhiguo kan guangming National Deep Sea Center State Oceanic AdministrationQingdao 266237China Key Laboratory of Marine Sedimentology and Environmental Geology The First Institute of OceanographyQingdao 266061China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China

In order to predict the bottom backscattering strength more accurately, the stratified structure of the seafloor is considered. The seafloor is viewed as an elastic half-space basement covered by a fluid sediment layer with finite thickness. On the basis of calculating acoustic field in the water, the sediment layer, and the basement, four kinds of scattering mechanisms are taken into account, including roughness scattering from the water-sediment interface, volume scattering from the sediment layer, roughness scattering from the sediment-basement interface,and volume scattering from the basement. Then a backscattering model for a stratified seafloor applying to low frequency（0.1-10 kHz） is established. The simulation results show that the roughness scattering from the sediment-basement interface and the volume scattering from the basement are more prominent at relative low frequency（below 1.0 kHz）. While with the increase of the frequency, the contribution of them to total bottom scattering gradually becomes weak. And the results ultimately approach to the predictions of the high-frequency（10-100 kHz） bottom scattering model. When the sound speed and attenuation of the shear wave in the basement gradually decrease, the prediction of the model tends to that of the full fluid model, which validates the backscattering model for the stratified seafloor in another aspect.

关键词： bottom backscattering model stratified seafloor sediment basement

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The sound velocity and bulk properties of sediments in the Bohai Sea and the Yellow Sea of China

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Acta Oceanologica Sinica 2016年第7期35卷 76-86页

作者： ZHENG Jiewen LIU Baohua kan guangming LI Guanbao PEI Yanliang LIU Xiaolei Key Laboratory of Marine Sedimentology and Environmental Geology of State Oceanic Administration State Oceanic Administration Qingdao 266061 China First Institute of Oceanography State Oceanic Administration Qingdao 266061 China Qingdao National Laboratory for Marine Science and Technology Qingdao 266237 China National Deep Sea Center State Oceanic Administration Qingdao 266237 China Shandong Provincial Key Laboratory of Marine Environment and Geological Engineering Ocean University of China Qingdao 266100 China

In order to investigate the correlation between a sound velocity and sediment bulk properties and explore the influence of frequency dependence of the sound velocity on the prediction of the sediment properties by the sound velocity, a compressional wave velocity is measured at frequencies of 25-250 kHz on marine sediment samples collected from the Bohai Sea and the Yellow Sea in laboratory, together with the geotechnical parameters of sediments. The results indicate that the sound velocity ranges from 1.232 to 1.721 km/s for the collected sediment samples with a significant dispersion within the series measuring frequency. Poorly sorted sediments are highly dispersive nearly with a positive linear relationship. The porosity shows a better negative logarithmic correlation with the sound velocity compared with other geotechnical parameters. Generally, the sound velocity increases with the increasing of the average particle size, sand content, wet and dry bulk densities, and decreasing of the clay content, and water content. An important point should be demonstrated that the higher correlation can be obtained when the measuring frequency is low within the frequency ranges from 25 to 250 kHz since the inhomogeneity of sediment properties has a more remarkably influence on the laboratory sound velocity measurement at the high frequency.

关键词： sound velocity particle composition physical properties frequency dispersion empirical equation

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Self-contained in situ sediment acoustic measurement system based on hydraulic driving penetration

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High Technology Letters 2011年第3期17卷 311-316页

作者： kan guangming Liu Baohua Zhao Yuexia Li Guanbao Pei Yanliang College of Marine Geosciences Ocean University of China Qingdao 266003 P.R. China Key Laboratory of Marine Sedimentology and Environmental Geology of State Oceanic Administration First Institute of Oceanography State Oceanic Administration Qingdao 266061 P.R. China

A novel self-contained in situ sediment acoustic measurement system based on hydraulic driving penetration is proposed to solve the problem of large disturbances to sediments of the in situ equipments already in existence. By using a hydraulic driving device, the system drives four acoustic probes into sediments at an even speed, and this decreases disturbances to sediments introduced by the penetration of acoustic probes. By means of the special design of the central control unit, the system can work full-automatically and the data are stored self-containedly, and this avoids the requirement of real-time remote controlling from the ship. Its operating water depth, measuring depth and measuring frequency is 500m, 1.0m and 30kHz respectively. A set of in situ sound speeds and attenuation coefficients of sediments are obtained at 40 stations using the system. The results confirm that the data obtained by the in situ sediment acoustic system are accurate and credible. Copyright © by HING TECHNOLOGY LETTERS PRESS.

关键词：液压驱动装置沉积物声学测量系统原位渗透数据存储设备中央控制单元声波探测器

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A Method for Calculating Bottom Backscattering Strength Using Omnidirectional Projector and Omnidirectional Hydrophone

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Journal of Ocean University of China 2019年第2期18卷 358-364页

作者： YU Kaiben YU Shengqi LIU Baohua LIU Zhongchen YANG Zhiguo kan guangming ZONG Le College of Marine Geo-Sciences Ocean University of China National Deep Sea Center State Oceanic Administration Laboratory for Marine Geology and Environment Pilot National Laboratory for Marine Science and Technology (Qingdao) Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of Oceanography

A method of obtaining bottom backscattering strength by employing an omnidirectional projector and omnidirectional hydrophone is proposed. The backscattering strength is extracted from monostatic backscattering data. The method was adopted in an experiment conducted in the South Yellow Sea of China. The seafloor surface was relatively smooth and covered by a small quantity of shell fragments, as observed through a digital camera system. Sampling data showed that the main component of the sediment at this experimental site was fine sand. In this paper, we detail the calculation method. Preliminary results of backscattering strength as a function of grazing angle(20?–70?) in the frequency range of 6–24 kHz are presented. The measured backscattering strength increased with the grazing angle and changed more rapidly at large grazing angles(60?–70?). A comparison of the data at different frequencies reveals that the measured backscattering strength substantially rises with the increase of acoustic frequency. A fitting curve of Lambert's law against the measured data shows that the backscattering strength deviates from Lambert's law at large grazing angles.

关键词： acoustic scattering bottom backscattering strength fine sand Lambert’s law

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中国近海主要表层沉积物类型的原位声学特性

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哈尔滨工程大学学报 2024年第1期45卷 189-197页

作者：李官保王景强孟祥梅阚光明刘保华自然资源部第一海洋研究所海洋地质与成矿作用部重点实验室山东青岛266061 崂山实验室山东青岛266237 国家深海基地管理中心山东青岛266237

海底表层沉积物的声学特性对于海洋声传播和声探测有重要影响。不同类型的海底沉积物表现出不同的声学特性。针对海洋声学研究对海底声学特性参数快速获取的需求,本文利用近年来获得的100个站位的声学特性原位测量和沉积物样品测试数据... 详细信息

海底表层沉积物的声学特性对于海洋声传播和声探测有重要影响。不同类型的海底沉积物表现出不同的声学特性。针对海洋声学研究对海底声学特性参数快速获取的需求,本文利用近年来获得的100个站位的声学特性原位测量和沉积物样品测试数据,统计了中国近海8种典型沉积类型的声速、声衰减系数等声学特性和平均粒径、密度等物理性质。通过与已有测量数据和统计结果的对比显示,其与多种原位测量系统获得的数据有很好的一致性,但Hamilton统计的声速比、声衰减因子等参数则显著偏高。基于VGS理论的频散模型计算结果表明:Hamilton统计结果的偏高并非完全由其较高的测量频率引起。对于缺少直接测量数据的海域,本文的统计结果提供了一种基于沉积物类型进行海底声学特性初步估计的方案。

关键词：沉积类型声速声衰减频散原位测量密度孔隙度中国近海

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