Decimeter-resolution fault zone topography mapped with Structure-From-Motion

Edwin Nissen, Ramon R. Arrowsmith, & Srikanth Saripalli

Published December 2012, SCEC Contribution #1735

We describe an affordable and accessible new system for generating decimeter resolution, textured topographic maps along active faults using a digital camera mounted on the underside of an autonomous helicopter. Point elevations of target pixels are determined using Structure-From-Motion (SFM), whereby movement between sequential photographs creates enough parallax to infer 3D structure. We showcase DEMs generated at sites on the southern San Andreas Fault and the 1992 Landers earthquake rupture, and compare these to airborne and terrestrial LiDAR DEMs from the same locations. The spacing of ground returns is finer than is typical for airborne laser scanning, allowing us to image offsets generated in previous ground-rupturing earthquakes that are too small or too subtle to be detected with LiDAR. However, observed footprints are much narrower than airborne LiDAR swaths, so the system is suited to the rapid collection of imagery for known targets rather than to reconnaissance missions of unmapped areas.

Nissen, E., Arrowsmith, R. R., & Saripalli, S. (2012, 12). Decimeter-resolution fault zone topography mapped with Structure-From-Motion. Oral Presentation at AGU Fall Meeting 2012.