In PSDM we see several events which are broken or not continuous. For the most clear examples, look in the upper right corner, at the line that doesn't line up correctly and in some cases is barely visible, and at the “S” shaped event where amplitude is lost.
Foothills One-way Wave Equation Model
In order to achieve good imaging in complexly thrusted areas such as the Canadian Foothills, several key issues must be addressed: in particular, the presence of very rough surface topography and structural complexity. On steep deeps (for example, in the top and middle of the image), one-way wave equations (Kirchhoff, WEM) loses the image.
Foothills RTM with Velocity Model
Seismic imaging in compression belts such as the Canadian Foothills is very challenging due to complex geological structures, rugged surface topography, and highly variable near-surface conditions. Seismic sections across the Canadian Foothills are usually progressively more distorted when approaching the Canadian Foothills region. Figure 1 shows the degree of structural complexity and topographic variations which are in part responsible for the deteriorated imaging in the thrust belt. Accurate velocity models of subsurface structures are critical for improving seismic images of thrust belts in both the time domain (e.g., tomostatics) and the depth domain (e.g., prestack depth migration).
Some of the events at the top of the model are nearly impossible to image with WEM or PSDM.
