Imaging complex structures with first-arrival traveltimes |
In their 1993 Geophysics article, Geoltrain and Brac ask the question ``Can we image complex structures with first-arrival traveltime?'' They conclude that they cannot, and that they should either ray trace to find the most energetic arrivals, or calculate multiple-arrival Green's functions. Nichols (1994) calculates band-limited Green's functions to estimate the most energetic arrivals. He estimates not only traveltime, but also amplitude and phase. My approach is simpler; by breaking up the complex velocity structure, I am able to calculate traveltimes in velocity models where finite-differencing the eikonal equation is valid. This results in images comparable to those obtained by Nichols' method and by shot-profile migration at a reduced computational cost.
Like most of the other researchers in the field, I test my method on the ever-popular Marmousi synthetic.
Imaging complex structures with first-arrival traveltimes |