Abstract
High porosity marine mud from different sites typically contains varying amounts of clay, sand, and silt particles, along with other material. A recent theory [Pierce, Siegmann, Brown, POMA 29, 005003 (2016)] explored a mechanism for how silt particles in suspension cause dominant contributions to the frequency dependence of compressional wave attenuation. The card-house structure of the clay is critical in supporting the particles and keeping them separated. Sample calculations for spherical particles of the same size showed physically reasonable attenuation behavior at low and high frequencies. This presentation provides extensions of the theory, such as accounting for distributions of particle sizes. Two approximation techniques are illustrated for this case and show very similar results. Of specific interest is determining the frequency band over which attenuation increases nearly linearly with frequency, as is often assumed. Assuming a single particle size shows conveniently the parametric behavior of linear frequency bands. For example, using sediment parameters from a 2016 core, a 16 μm spherical-particle radius has such a band from ∼1.4 - 2.6 kHz. As the particle radius decreases, the bands widen and are centered at increasing frequency; for a particle radius half as large, the relevant band is ∼5.5 - 10.5 kHz.
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