Estimating velocity ratio in marine sediment

Presented in this letter are least-squares regression relationships between velocity ratio (R; the ratio between surficial sediment sound speed and bottom water sound speed) and sediment mean grain size (Mz, phi units), porosity (η, %), and density (ρ, kg/m3). The relationships are: R=1.296−6.01×10−2 Mz +2.83×10−3 Mz2; R=1.675−1.639×10−2 η +9.762×10−5 η2; and R=1.513−8.24×10−4 ρ+3.2249×10−7 ρ2. These equations, respectively, explain 91.6%, 88.0%, and 86.4% of the variation observed in velocity ratio. Velocity ratio relationships are more convenient than those previously available because they do not require temperature and pressure correction to in situ conditions.