Seismic imaging of sea-bed sediments using vertical-cable method


Institute of Geophysics, University of Tehran, P.O. Box 14155-6466, Tehran, Iran


In marine seismic surveys amplitudes, frequency contents and travel times of seismic waves are influenced significantly by elastic and physical properties of sea-bed sediments. Therefore, investigation of elastic properties of propagation medium at the bottom of the sea floor is worth while  in marine seismic studies.
In this paper refraction arrival times are analyzed to estimate the velocity structure and anisotropic parameters of sea-bed sediments using a vertical-cable (VC) configuration.
Two sets of synthetic seismic data from two distinct earth models were used to evaluate the influence of dip and anisotropy of layers on propagation of seismic waves. In the first set of data, for a constant value of anisotropy, the values of   and  were assigned to dip in order to evaluate the influences of dip. However, in the second set of models, we kept the dip constant and varied the P-wave anisotropy strength of the medium to examine the sensitivity of ray-slowness to anisotropy. All above mentioned analyses were done on synthetic P-wave VC seismic records, which were obtained by solving of eikonal equation using finite-difference method. Our result indicated the usefulness of the VC acquisition method for determination of real dip , dip azimuth , azimuth of symmetry axis with respect to the X-axis  and anisotropic parameters  of the saturated sea-bed sediments.