Complex seafloor bathymetry can create significant challenges for subsurface imaging and geologic interpretation of seismic exploration and monitoring data. Steep seafloor canyons that cut through continental shelf areas can produce very strong seismic wavefield distortions. Neglecting such wavefield complexity can result in inaccurate velocity models, significant imaging errors, misleading amplitudes, and erroneous geologic interpretations. We have evaluated the kinematic and dynamic effects of seismic prism waves generated by seafloor canyons. Prism waves are seismic waves that undergo consecutive reflections at a scattering interface before propagating to the recording sensor array. We have demonstrated that strong prism waves can be generated for realistic seafloor canyon geometries, and we determined how their adverse effects can contaminate seismic imaging and velocity estimation.