Correlation between acoustical and other physical properties of deep-sea cores

Abstract

A study of 22 cores confirms that certain bulk and textural properties of deep‐sea sediments have a definite bearing on the transmission speed of sound through marine deposits. The higher the porosity, moisture content, and void ratio, the lower is the sound velocity. Increases in wet density are matched by increases in transmission speeds. There is no apparent correlation between sound velocity and either dry density or carbonate content. Shear strength is not a reliable index of transmission speed. Sound velocity is strongly related to grain size. Turbidites have high velocities, ash layers have intermediate velocities, and deep‐sea muds and clays have low velocities. There is a relation between transmission speed and sorting, skewness, and transformed kurtosis, but these size measures are dependent upon mean grain size. Grain size governs the bulk and textural properties of unconsolidated marine sediments and is the most important physical property in determining the acoustical nature of deep‐sea cores.

Acoustic environment of the Hatteras and Nares Abyssal Plains, western North Atlantic Ocean, determined from velocities and physical properties of sediment cores

“…Such a direct r elation has been demons trated empirically in previous s tudies by Horn et a /. 24 a nd Hamilton . 6 Velociti es in clay -size sediments ty pically are 1510-1530 m/ s; in s ilts , 1600-1700 m/ s ; and in s ands, up to 1850 m/s .…”

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

“…Mˆmean grain diameter after Inman (1952) (in units) vˆacoustic velocity (in m/s) v ¤ˆv elocity ratio (ˆratio of sediment velocity to seawater velocity) Fˆacoustic impedance (in kg/m 2 s) IOIˆindex of impedance (ˆproduct of velocity ratio and bulk density, in g/cm 3 ) A great number of empirical studies have been published, investigating the relationships between acoustic velocity of marine sediments and physical properties such as porosity, density, and mean grain size (e.g., Sutton, Berekhemer, and Nafe, 1957;Horn, Horn, and Delach, 1968;Schreiber, 1968;Morgan, 1969;Hamilton, 1970Hamilton, , 1974Buchan, McCann, and Smith, 1972;Akal, 1972;Anderson, 1974;Hamilton and Bachman, 1982). More recent studies have incorporated acoustic impedance as a second acoustic property and observed very good correlations with porosity and density, and to some lesser extent with mean grain size (Bachman, 1985;Richardson and Briggs, 1993).…”

Sound Velocity, Elastic Constants, and Related Properties of Marine Sediments in the Western Equatorial Pacific: Leg 7, Glomar Challenger

“…It has been noted by Hamilton et al (1966), Shumway (1960), Sutton, et al (1957), Schreiber (1968), Horn et al (1968), and others that a relationship exists between grain size parameters and sonic velocity. Hardin and Richart (1963) and Schon (1963) point out that this relationship derives primarily from the relationship that both of these parameters have with porosity.…”