A Full-wave Equation Based Seismic Illumination Analysis Method

We propose a full-wave equation based method for seismic illumination analysis. The full-wave finite-difference method is used to calculate the waves from the source and receiver to the subsurface target. A time domain local slowness analysis technique is used to decompose the wavefield into angle domain beams. Based on the angle domain information, we formulate the illumination matrix from which different illumination measurements can be derived. Unlike the one-way wave equation based method, the current approach does not have the angle limitation and the reflection/transmission energy can be accurately calculated. The new illumination method can handle turning waves which are crucial for imaging steep structures. Thus, this method is particularly useful for providing illumination analysis in reverse-time migration. A group of numerical examples are calculated to demonstrate the time-domain wavefield decomposition and the creation of different illumination measurements. The illumination in the 2D BP model is investigated. Our special attention is focused on the illumination of vertical and overhung structures.