REFRACTION MEASUREMENT OF SHEAR WAVE ANISOTROPY IN SHALLOW MARINE SEDIMENTS AND IMPLICATIONS FOR REFLECTION PROCESSING

In 1986, an on-bottom shear wave source and a multi-component on-bottom receiver with a hydrophone were used by Woods Hole Oceanographic Institution and Ron­ dout Associates, Inc. to record a short « 200 m) refraction profile near the United States Geological Survey's AMCOR drill holl' !lOll, off the coast of New Jersey. Synthetic seismo­ grams match amplitudes and travel times for all components only if a transversely isotropic model is used. The data req ui re a "" 10-m- thick layer with", l!l% shear wave anisotropy, overlying a 40-m-thick isotropic region. This model agrees with drill core data showing 10 m of silty day overlying 40 m of sand. If a conventional reflection profile were recorded, the interval velocity would be overestimated by about 84% for SV-waves in the silty clay.