Interval velocity and thickness estimate from wide-angle reflection data

A method to estimate interval velocities and thickness in a horizontal isot ropic layered medium from wide-angle reflection traveltime curves is presen ted. The method is based on a relationship between the squared reflection t raveltime differences and the squared offset differences relative to two ad jacent reflectors. The envelope of the squared-time versus offset-differenc e curves, for rays with the same ray parameter, is a straight line, whose s lope is the inverse of the square of the interval velocity and whose interc ept is the square of the interval time. The method yields velocity and thic kness estimates without any knowledge of the overlying stratification. It c an be applied to wide-angle reflection data when either information on the upper crust and/or refraction control on the velocity is not available. App lication to synthetic and real data shows that the method, used together wi th other methods, allows us to define a reliable 1D starting model for esti mating a depth profile using either ray tracing or another technique.