Tests of new in-situ seabed acoustic measurement system in Qingdao

Hou, Zhengyu; Guo, Changsheng; Wang, Jingqiang; Li, Hui-Yin; Li, Tiegang

doi:10.1007/s00343-015-4013-1

Cited by 18 publications

(4 citation statements)

References 20 publications

(19 reference statements)

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“…Wang et al [34] had researched the relation between the acoustic characters of sea bottom sediment and seawater depth, they found that when the water depth less than 1000 m, the influence of depth on sound velocity can be ignored. In fact, changes in temperature and pressure are inevitable for sampling measurement, thus, the development of in situ measurement techniques is important for the measurement of sound velocity in seafloor [35].…”

Section: Sound Velocitymentioning

confidence: 99%

Seafloor Sediment Study from South China Sea: Acoustic & Physical Property Relationship

et al. 2015

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Seafloor sediments of different geographical areas in the southern South China Sea (continental shelf, continental slope, and Okinawa Trough) were gravity cored at 21 locations. Sound velocities (V) of the samples were measured at 15-cm increments immediately upon retrieval, and porosity, wet bulk density, and mean grain size were measured later in the laboratory. Empirical equations from previous studies were applied to predict V of sediment samples from the measured physical properties and it was found that the sound velocities derived from the existing equations did not closely match the measured sound velocities. Therefore empirical equations were reconstructed based on the measured data that represent the relationships between physical and acoustic properties of the different geographical area in the study area. Possible explanations for the discrepancies between the measured data and those of previous studies were investigated and found that physical properties, sediment types, geographical area, etc. are important factors that influence sound velocity. The empirical equations of this report should be preferred for prediction of sediment sound velocity for high-frequency acoustic experiments.

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Section: Sound Velocitymentioning

confidence: 99%

Seafloor Sediment Study from South China Sea: Acoustic & Physical Property Relationship

et al. 2015

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“…1. In situ measurements: Since the 1990s, several in situ techniques have been developed and used to measure acoustic properties, including the in situ sediment geoacoustic measurement system (Richardson and Briggs, 1996), sediment acoustic and physical property apparatus (Best et al, 2001), in situ sound speed and attenuation probe (ISSAP) (Kraft et al, 2002), acoustic lance (AL) (Fu et al, 2004), sediment acoustic speed measurement system (Yang et al, 2008), multifrequency in situ geoacoustic measurement system (Tao et al, 2009), hydraulicdriven in situ sediment acoustic measurement system (HSISAMS) (Kan et al, 2011), drag-type in-situ acoustic measurement system (Hou et al, 2014), the ballast in situ sediment acoustic measurement system (BISAMS) (Wang et al, 2018). These can obtain the closest approximation to the real data, but at the highest cost and with complex operational processes; currently, such measurements have only been applicable to the shallow seafloor.…”

Section: Introductionmentioning

confidence: 99%

On-deck vs. laboratory analyses of the sound velocity of sediments from the Huanghai and Bohai seas

Liu,

Zheng,

Wang

et al. 2024

Front. Mar. Sci.

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One popular method of obtaining the acoustic parameters of seabed sediments is by measuring the sound velocity of sediment samples in a laboratory. However, the effects of environmental variation and physical perturbation on acoustic properties are typically neglected in the application of such measured acoustic parameters. In this study, sediment samples were collected from the Huanghai and Bohai seas to measure sound velocity both on the deck and in the laboratory using a digital sonic measuring system. Additionally, sediment compositions, physical and mechanical properties and microstructures were determined. Sound velocity comparisons between on-deck and laboratory measurements indicate that laboratory-measured velocities are generally higher than those measured on the deck, with differences ranging from 1.45 m/s to 130.05 m/s, due to the water loss and densification of sedimentary particles in laboratory settings. The discrepancy of sound velocities measured in the laboratory and on the deck also differ based on the types of sediments sampled. Overall, the discrepancy increases with measurement frequency, increasing average grain diameter and sand content, as well as with decreasing clay content.

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“…Compared with the sampling measurement, in situ measurement introduces less disturbance to the seafloor sediment (especially deep‐sea soft sediments), and the environmental temperature and pressure will not change during the measurement, resulting in more accurate results that reflect the actual state of the seafloor sediments. Various techniques have been developed for acoustic in situ measurement of seafloor sediment, mainly including the in situ sediment acoustic measurement system (Richardson & Briggs, 1996), the acoustic lance (Gorgas et al., 2002), the hydraulic‐driven in situ sediment acoustic measurement system (Liu et al., 2013), the acoustic coring system assembled with a gravity core (Megan et al., 2019), the drag‐type in situ acoustic measurement system (Hou et al., 2014), the sediment acoustic‐speed measurement system (SAMS) (Yang & Jackson, 2020) and the ballast in situ acoustic measurement system (Li et al., 2019; Wang et al., 2018). These techniques have been widely applied in studying the acoustic properties of seafloor sediment in different marine regions.…”

Section: Introductionmentioning

confidence: 99%

Time difference auto‐extraction methods for in situ sound speed measurements in seafloor sediments

Hua,

Wang,

et al. 2024

Geophysical Prospecting

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The in situ acoustic measurement of seafloor sediment is an important technical means to obtain the acoustic parameters of seafloor. The time‐of‐flight method is commonly used to calculate the sound speed in seafloor sediment. Accurate identification of signal feature points is essential for determining travel time or travel time difference of acoustic signals. However, the precise identification of feature points, such as the take‐off point of the first wave of a sound wave signal, is challenging. The conventional manual identification method is inefficient and prone to errors. The development of a feature point auto‐identification method is imperative for accurately calculating the travel time of acoustic signals. In this study, we employed the cross‐correlation method, the level threshold method and the short window‐long window energy ratio method to extract the acoustic travel time differences and calculate the sound speeds in seawater and in seafloor sediment. We then analysed the effectiveness of these calculated results. The sound speeds in seawater obtained through the aforementioned methods were compared with the sound speeds measured using a sound velocity profiler. The comparison revealed that these processing methods exhibit a high level of accuracy. The sound speed results in sediments show that the programme‐based auto‐identification methods significantly reduce the standard deviation compared to the manual identification method. This study successfully assessed the processing accuracy of different methods and expanded the processing methods for in situ acoustic signals of seafloor sediments.

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Tests of new in-situ seabed acoustic measurement system in Qingdao

Cited by 18 publications

References 20 publications

Seafloor Sediment Study from South China Sea: Acoustic & Physical Property Relationship

Seafloor Sediment Study from South China Sea: Acoustic & Physical Property Relationship

On-deck vs. laboratory analyses of the sound velocity of sediments from the Huanghai and Bohai seas

Time difference auto‐extraction methods for in situ sound speed measurements in seafloor sediments

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