Abstract

Depth Imaging uses processed surface seismic data to estimate models and produce images of the Earth’s subsurface with their features correctly positioned in depth. Depth models describe the seismic properties of the subsurface, allowing us to characterise the non-linear relationship between the structure of physical features generating seismic reflections, and the seismic data recorded at the surface. Depth Migration uses these models to produce an image by correctly repositioning the recorded seismic data. Ray-based Tomography and Full Waveform Inversion are the key methods used to obtain these models.I will review the role of these two key inverse problems in seismic depth imaging and explore how advances in modelling the physics of seismic wave propagation (especially seismic anisotropy and elastic effects) have brought improved resolution and accuracy while complicating the inverse problem.