ABSOLUTE REFLECTION COEFFICIENTS FROM DEEP SEISMIC REFLECTIONS

Many deep Seismic reflection profiles show bright sub-horizontal layered reflections in the lower continental crust. Accurate estimates are obtained for normal incidence reflection coefficients for the brightest of these reflections by using a marine Seismic acquisition system that has been calibrated using deep-water sea-bottom multiples. Minimum bounds are placed upon these reflection coefficients by assuming minimum losses due to scattering, anelastic attenuation and geometric spreading. Reflection coefficients of around 0.1 are obtained from the layered lower crust and around 0.15 from the Moho. It is argued that constructive interference between successive reflections from a layered sequence of reflectors is often unimportant, consequently these coefficients can be used to place useful limits on the absolute acoustic impedance contrasts present at depth. © 1990.