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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

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 *** eliminate the influence of environ-mental factors,the empirical sound speed ratio equations were *** 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 ***,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 *** 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 *** 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

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 ***-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 *** 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 *** respect to surficial sediments,pore water plays a key role in the sound velocity ratio of sediment influenced by different environmental *** sound velocities of different types of sediments(sandy,silty,and clayey)change similarly with temperature,but change slightly differently with hydro-static *** influence of environmental factors on the sound velocity ratio of seafloor sediment is independent of the detec-tion *** 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

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

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： joint elastic-electrical properties marine sediments Yellow Sea effective medium models

Data processing of the Kuiyang-ST2000 deep-towed high-resolution multichannel seismic system and application to South China Sea data

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Journal of Oceanology and Limnology 2023年第2期41卷 644-659页

作者： Yanliang PEI Mingming WEN Zhengrong WEI Baohua LIU Kai LIU guangming kan Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Guangzhou Marine Geological Survey China Geological SurveyMinistry of Natural ResourcesGuangzhou 511458China College of Ocean Science and Engineering Shandong University of Science and TechnologyQingdao 266590China Laoshan Laboratory Qingdao 266237Chin

The Kuiyang-ST2000 deep-towed high-resolution multichannel seismic system was designed by the First Institute of Oceanography,Ministry of Natural Resources(FIO,MNR).The system is mainly composed of a plasma spark source(source level:216 dB,main frequency:750 Hz,frequency bandwidth:150-1200 Hz)and a towed hydrophone streamer with 48 *** the source and the towed hydrophone streamer are constantly moving according to the towing configuration,the accurate positioning of the towing hydrophone array and the moveout correction of deep-towed multichannel seismic data processing before imaging are ***,according to the characteristics of the system and the towing streamer shape in deep water,travel-time positioning method was used to construct the hydrophone streamer shape,and the results were corrected by using the polynomial curve fitting ***,a new data-processing workflow for Kuiyang-ST2000 system data was introduced,mainly including float datum setting,residual static correction,phase-based moveout correction,which allows the imaging algorithms of conventional marine seismic data processing to extend to deep-towed seismic *** successfully applied the Kuiyang-ST2000 system and methodology of data processing to a gas hydrate survey of the Qiongdongnan and Shenhu areas in the South China Sea,and the results show that the profile has very high vertical and lateral resolutions(0.5 m and 8 m,respectively),which can provide full and accurate details of gas hydrate-related and geohazard sedimentary and structural features in the South China Sea.

关键词： Kuiyang-ST2000 system deep-towed system seismic data process plasma spark source high resolution gas hydrate South China Sea

Sea-surface acoustic backscattering measurement at 6–25 kHz in the Yellow Sea

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Acta Oceanologica Sinica 2020年第3期39卷 113-122页

作者： Lehua Qi guangming kan Baohua Liu Yanliang Pei Zhiguo Yang Shengqi Yu College of Marine Geo-sciences Ocean University of ChinaQingdao 266100China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China National Deep Sea Center State Oceanic AdministrationQingdao 266237China

Sea-surface acoustic backscattering measurements at moderate to high frequencies were performed in the shallow water of the south Yellow Sea, using omnidirectional spherical sources and omnidirectional hydrophones. Sea-surface backscattering data for frequencies in the 6–25 k Hz range and wind speeds of(3.0±0.5)and(4.5±1.0) m/s were obtained from two adjacent experimental sites, respectively. Computation of sea-surface backscattering strength using bistatic transducer is described. Finally, we calculated sea-surface backscattering strengths at grazing angles in the range of 16°–85°. We find that the measured backscattering strengths agree reasonably well with those predicted by using second order small-roughness perturbation approximation method with "PM" roughness spectrum for all frequencies at grazing angles ranged from 40° to 80°. The backscattering strengths varied slightly at grazing angles of 16°–40°, and were much stronger than roughness scattering. It is speculated that scattering from bubbles dominates the backscattering strengths at high wind speeds and small grazing angles. At the same frequencies and moderate to high grazing angles, the results show that the backscattering strengths at a wind speed of(4.5±1.0) m/s were approximately 5 d B higher than those at a wind speed of(3.0±0.5) m/s. However, the discrepancies of backscattering strength at low grazing angles were more than 10 d B. Furthermore the backscattering strengths exhibited no significant frequency dependence at 3 m/s wind speed. At a wind speed of 4.5 m/s, the scattering strengths increased at low grazing angles but decreased at high grazing angles with increasing grazing angle.

关键词： sea-surface acoustic scattering moderate frequency scattering model bistatic backscattering frequency dependence

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

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.

关键词： acoustic properties sound speed sound attenuation in situ measurement system