A combination of geophysical techniques can yield estimates of several physical properties versus depth. An example is presented for a thick sequence of sediments in Middle Valley near the present spreading axis of the Juan de Fuca Ridge. We have computed the porosity, temperature, and thermal conductivity versus depth by combining the results of seafloor electrical and heat flow surveys. The electrical resistivity of the sediments is empirically related to the porosity of the medium and to the pore fluid electrical conductivity, which is in turn sensitive to the temperature. The temperature profile is determined from the heat flow and the thermal conductivity. The latter is determined from calculated porosity and estimates of the constituent mineral and pore fluid thermal conductivities. The measured surface heat flow is assumed to be, and the resistivity has been determined to be, approximately constant with depth. The computation of the variation of temperature, porosity, and thermal conductivity with depth yields physically realistic and reasonable results. Other physical properties (void ratio, bulk density, water content, compressional wave velocity) are estimated from the porosity. The shear wave velocity is calculated empirically from the compressional wave velocity, and Poisson's ratio is then computed from the compressional and shear wave velocities. The results are in good agreement with values derived for similar rapidly deposited sediment sequences elsewhere, but the model calculations indicate that Deep Sea Drilling Project measurements may be biased toward higher-porosity samples.