Combined Inversion of Seismic Waveforms and Traveltimes for Acoustic Waves

Seismic full waveform inversion (FWI) is a powerful method for obtaining high resolution subsurface images, but the objective function of waveform data typically contains many local minima that may lead to inappropriate solutions. This can be avoided by choosing an initial model that is close to the true model, and by incorporating only low frequencies at an early stage of an inversion run. Here, we demonstrate that the local minima problem can also be mitigated by simultaneously inverting waveforms and first arrival travel times. Using a simple two parameter example we show, how the addition of travel time data can remove a local minimum present in the waveform misfit function. Inversions of synthetic 2D acoustic data show that our novel combined travel time and waveform inversion approach leads to superior results compared with a pure FWI inversion.