Point-Perspective View of Ophir Chasm, Valles Marineris, Mars. Shown here is a synthetic oblique view from the south of landslides in Ophir Chasm. Three large landslide slump scarps 4 to 5 kilometers high appear in the center of the scene. 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. Helen's volcano. The longitudinal grooves seen in the foreground are thought to be the result of differential shear and lateral spreading at high velocities. The point-perspective view was produced by using two data sets. A digital mosaic of the area and a digital elevation model produced from a 1/500,000 scale typographic map (courtesy of Ray Jordan and Sherman Wu, U.S. Geological Survey). There is no vertical exaggeration. Image-processing was done by Alfred McEwen, U.S. Geological Survey, Flagstaff, Arizona.
