Submeter Resolution Surface Rupture Topography From Legacy Aerial Photographs - A Test Case From the 1992 Landers Earthquake
Date
2020
Authors
Lajoie, Lia J.
Nissen, Edwin
Johnson, Kendra L.
Lajoie, Kenneth R.
Journal Title
Journal ISSN
Volume Title
Publisher
Earth and Space Science
Abstract
The 1992 Mw 7.3 Landers earthquake in the Mojave Desert (California) provided exceptional observations of surface faulting in a large, continental earthquake. The U. S. Geological Survey obtained nadir angle, overlapping aerial photographs at 1:6,000 scale for the entire urn:x-wiley:ess2:media:ess2482:ess2482-math-0002 85 km rupture length. Recent advances in Structure from Motion photogrammetry allow for archival photographic data sets such as these to be reprocessed, generating digital topography that can be reanalyzed quantitatively in a way that was not previously possible. In this proof‐of‐concept study, we generated a georectified, urn:x-wiley:ess2:media:ess2482:ess2482-math-0003 10 points/m urn:x-wiley:ess2:media:ess2482:ess2482-math-0004 topographic point cloud over nearly the entire Landers rupture length and a higher‐resolution urn:x-wiley:ess2:media:ess2482:ess2482-math-0005 40 points/m urn:x-wiley:ess2:media:ess2482:ess2482-math-0006 point cloud over a smaller ( urn:x-wiley:ess2:media:ess2482:ess2482-math-0007 5 km) rupture segment along the Emerson fault. We estimated the accuracy and explore the utility of our point cloud in two tests. First, we observe close geometric agreement (average closest point distance 2.1 cm and standard deviation 14.0 cm) between our point cloud and a 2008 terrestrial lidar survey of the Galway Lake Road site on the Emerson fault. Second, we made 173 vertical offset measurements within a small, structurally complex pull‐apart basin, also on the Emerson fault, and find visual and statistical similarity with 21 local field measurements. These two tests demonstrate that point clouds generated from legacy aerial surveys and georeferenced using free Google Earth and National Elevation Dataset imagery are geometrically accurate and can be used to densify geomorphic offset measurements even along well‐studied surface ruptures. Applied to other historical events, such measurements could provide new insights into earthquake rupture processes.
Description
Keywords
high-resolution topography, Structure from Motion, earthquake surface rupture
Citation
Lajoie, L. J., Nissen, E., Johnson, K. L., & Lajoie, K. R. (2020). Submeter Resolution Surface Rupture Topography From Legacy Aerial Photographs – A Test Case From the 1992 Landers Earthquake. Earth and Space Science, 7(3), 1-13. https://doi.org/10.1029/2019EA000651.