Sediment Classification by Seismic Reflectivity

A semi-automatic, electronic system used to measure seismic reflectivity of the water-bottom sediment is devised. The central part of the system is an apparatus designed to negate waveform spherical divergence using a linear ramp function coupled with a voltage multiplier circuit. A time gating circuit allows any part of the multiplier output to be amplified and preserved on a unique galvanometer camera record. Using a 3.5 kilohertz acoustic signal, Eastern Block Island Sound is mapped for reflectivity. A regression equation is established between reflection amplitude and water-bottom sediment mean grain size. A water-bottom, Wentworth sediment classification map is thereby obtained. Application of this method would include optimum offshore pipeline routing, platform location, and mineral exploration.