Assessing the ability of Pleiades stereo imagery to determine height changes in earthquakes: a case study for the El Mayor-Cucapah epicentral area

High-resolution surface topography is valuable for studying coseismic fault zone deformation and fault geometry. It enables us to measure three-dimensional surface displacements in earthquakes, as shown in recent studies that used light detection and ranging (LiDAR) to determine coseismic motion. However, the applicability of LiDAR is limited by its relatively high cost and low availability. In this study, we use the 2010 El Mayor-Cucapah earthquake to demonstrate the capability of Pleiades stereo imagery to measure coseismic vertical ground displacement. We acquired post-earthquake Pleiades tri-stereo imagery from backward, near-nadir and forward orientations for a 45 km × 7 km portion of the epicentral area. 1-m resolution digital elevation models (DEMs) were produced with the four different combinations of incidence angles and compared to the post-earthquake LiDAR DEM. Elevations from tri-stereo have slightly (∼15%) smaller uncertainties than bi-stereo as the tri-stereo DEM incorporates more observations. Elevation differences between the Pleiades and post-earthquake LiDAR DEMs show that the vertical accuracy of the Pleiades DEMs is ∼0.3 m. By differencing the Pleiades DEM and the pre-earthquake, 5-m resolution LiDAR DEM, we mapped metre and sub-metre offsets along the faults obtaining results comparable to a previous study that differenced the two LiDAR DEMs. This is the first case study of assessing very high-resolution (VHR) satellite stereo imagery to determine sub-metre vertical ground displacement in an earthquake. By extension, we expect it to be possible to measure sub-metre vertical offsets occurring in earthquakes using pre- and post-earthquake VHR stereo imagery