Concentric Crater FloorThis Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows the interior of a typical crater in northern Acidalia Planitia. The floor is covered by material that forms an almost concentric pattern. In this case, the semi-concentric rings might be an expression of eroded layered material, although this interpretation is uncertain. The crater is located near 44.0°N, 27.7°W, and covers an area about 3 km (1.9 mi) wide. Sunlight illuminates the scene from the lower left.
Image Credit: NASA/JPL-Caltech/MSSS