OpenTopography enables detailed analysis of San Andreas Fault--new results published in SCIENCE
Recent ASU Ph.D. and current Post-doc Olaf Zielke and OpenTopography Co-I Ramon Arrowsmith and colleagues published the results of their study of offset channels along the southern San Andreas Fault in Science last week. They had two reports in the issue which were also highlighted in a perspective by Kate Scharer of Appalachian State University. The cover image of Science featured a 0.25 m digital elevation model (DEM) and hillshade of offset channels along the San Andreas Fault in the Carrizo Plain produced by OpenTopography.
The Zielke, et al. study used 0.25 and 0.5 m DEMs generated using the point cloud and custom DEM component of OpenTopography on the B4 dataset and reconstructed their offsets from prior major earthquakes (in particular the last great one of 1857) along the San Andreas Fault to refine our understanding of what happens when the fault slips there. They concluded (in part) that 1) there was no indicator for (strong) fault segmentation, 2) individual sections of 1857 rupture may be activated independently, 3) earthquake occurrence may be bimodal with major full rupture events dominating the strain release and moderate partial rupture events decreasing the recurrence interval of surface rupturing earthquakes, and 4) the open interval since 1857 is similar to or greater than the recurrence rate of earthquakes on that portion of the San Andreas Fault.
The B4 "Southern San Andreas Laser Scan" dataset is comprised of several billion individual laser returns. OpenTopography made it easy to select and process the portion of the data set that covered the offset landforms of interest.
Direct links to the Science Cover, Reports, and the Perspective:
Climate-Modulated Channel Incision and Rupture History of the San Andreas Fault in the Carrizo Plain by Grant Ludwig, et al.
Slip in the 1857 and Earlier Large Earthquakes Along the Carrizo Plain, San Andreas Fault by Zielke, et al.
PERSPECTIVE on GEOPHYSICS: Changing Views of the San Andreas Fault by Katherine Scharer