Deterministic source signature deconvolution has been applied to the processing of marine airgun wide angle and vertical profiler data. The resulting improvement in reflection event timing accuracy allowed the computation of more reliable interval velocities for upper sedimentary layers by theT2−X2method, provided that the layer thickness limitation of the method was not exceeded. Computations of frequency dependent attenuation were also made from the data by a procedure using frequency domain univariate least‐squares regression. Estimates of maximum attenuation were made for an abyssal plain and a turbidite sedimentary environment off the coast of Oregon. The interval velocity and attenuation in the upper layers of the turbidite environment correlate well with the average material type found in the core of nearby DSDP site 174 (sandy silt with greater than 60% sand). The maximum estimated attenuation at about 100 Hz in the abyssal plain environment (silts and clays) was found to be greater than that for the sea fan environment.