Abstract: Disclosed are an apparatus and method for visualizing subsurface velocity structure by processing signals through waveform inversion in the Laplace-Fourier domain, and a recording medium storing a program for implementing the method. A receiver receives a seismic signal from a target region, and a signal processor processes the seismic signal to generate image data for visualizing the subsurface structure of the target region. The signal processor performs the waveform inversion in the Laplace-Fourier domain, thereby obtaining a velocity model similar to an true structure of the target region.

Abstract: A Laplace transform system comprising a processor, a measured time domain wavefield, a velocity model, and Laplace damping constants, wherein the processor is programmed to calculate a substantially about zero frequency component of a Fourier transform of a time domain damped wavefield, wherein the time domain damped wavefield is damped by the Laplace damping constants to obtain long wavelength velocity information for deeper subsurface regions.