Summary
3D reflection seismic data collected as a part of the NanTroSEIZE project revealed complex interactions between active sedimentation and tectonics in the Nankai Trough, Japan. We implemented co-rendering of multiple attributes and stratal slicing in python to better visualize the structural and stratigraphic relationships within the piggyback slope basins of the accretionary prism.
Description
3D reflection seismic data acquired offshore of southeast Japan as part of the Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) provides a unique opportunity to study active accretionary prism processes. The 3D seismic volume revealed complex interactions between active sedimentation and tectonics within multiple slope basins above the accretionary prism. However, our ability to understand these interactions was hindered without access to expensive specialized software packages.
We implemented stratal slicing of the 3D volume and co-rendering of multiple attributes in python to better visualize our results. Stratal slicing allows volumetric attributes to be displayed in map view along an arbitrary geologic timeline(~30MB animated gif) by interpolating between interpreted geologic surfaces. This enhances the visibility of subtle changes in stratigraphic architecture through time. Co-rendering coherence on top of seismic amplitudes facilitates fault interpretation in both cross section and map view. This technique allowed us to confidently interpret faults near the limit of seismic resolution.
The scientific python ecosystem proved to be an effective platform both for making publication-quality cross sections and for rapidly implementing state-of-the-art seismic visualization techniques. We created publication quality cross sections (some annotations added in Inkscape) and interactive 2D visualizations in matplotlib. For 3D display of seismic volumes we used mayavi to easily create interactive scenes. scipy.ndimage provided most of the underlying image processing capability and allowed us to preform memory-efficient operations on >10GB arrays.
