Using historical satellite data to measure ground deformation in the 1973 Luhuo earthquake, Eastern Tibet
Advisor : James HOLLINGSWORTH (ISTerre)
Location : ISTerre (team : Cycle)
Keywords : remote sensing, earthquakes, geodesy, image processing, mapping, geomorphology, Tibet
In this project the student will explore the use of stereo KH-4 Corona optical satellite imagery to measure earthquake deformation in the 1973 Luhuo earthquake using the optical image correlation technique. Firstly, due to the large image size, sub-pixel registration techniques will be used to stitch together each KH-4 image tile, to restore the image to its full size with limited mosaicing artifacts. Secondly, large distortions in the KH-4 satellite scenes, which result from the complex KH-4 camera system, will be approximated using Rational Polynomial Coefficients (estimated from ground control points taken from existing satellite and topographic data). Bundle adjustment of several overlapping images will allow a more precise characterization of the distortion pattern, which is different in the forward and backward looking view directions, as well as precise registration of each image to it’s neighbor. Each image will be undistorted, and a digital elevation model will extracted for each stereo pair, which will then be used to orthorectify each image (to remove the topographic distortion). Co-registration of the pre-earthquake KH-4 data with post-earthquake satellite images (KH9, SPOT and Landsat), and subsequent correlation will be used to characterize the ground deformation produced in the 1973 earthquake. Ground deformation will be examined in relation to the long-term geomorphology to determine the link between short-term (co-seismic) and long-term (multiple earthquake cycle) deformation. If time permits, we may explore the potential for using KH-4 imagery to retrieve ground deformation associated with landslides, and dike injection.