Subsurface Imaging Using Approximate Stationary Positions

We propose using approximate stationary positions to estimate subsurface P-wave velocity structure with neither subsurface information nor initial model. Considering characteristic of stationary zone in the convolution gather, we estimate stationary positions (i.e., angles of incidence) approximately by adding a virtual layer above the real media. By applying Snell’s law, probability density function and Fermat’s principle to a range of assumed velocities for the lower layer, we use estimated approximate stationary positions to resolve velocities and structures of the subsurface. Unlike the conventional imaging techniques affected by initial models, our method is completely independent of initial models, but still needs accurate picking of the primary reflections. Nemerical example demonstrates that our method produces high-quality subsurface media including low-velocity layers.