Oblique views of Ophir Chasm, Valles Marineris, Mars. Shown in this set of three images are synthetic oblique views of landslides in Ophir Chasm, looking from the south, east and west with the observer located 25 degrees above the horizon. Vertical exaggeration two times. Three large landslide slump scarps 4-to-5 kilometers high appear in the center of the scene and part of the fourth slump scarp is visible at the extreme east margin. The volume of the landslide debris is more than 1,000 times greater than that from the May 18, 1980 debris avalanche from Mount St. Helens volcano. The longitudinal grooves seen in the foreground are thought to be the result of differential shear and lateral spreading at high velocities. Oblique view was produced by orthographic rotation using two data sets: a digital mosaic of the area and a digital elevation model produced from a 1/500,000 scale topographic map (courtesy of Ray Jordan and Sherman Wu, U.S. Geological Survey). Image processing was done by Alfred McEwen, U.S. Geological Survey, Flagstaff, Arizona.
