MGS MOC Release No. MOC2-508, 9 October 2003

Arabia Terra is a vast, heavily cratered region in the martian northern hemisphere. Much of Arabia Terra is thickly blanketed by dust. From time to time, on steep slopes, the dust will avalanche or slide downhill, creating a streak. The majority of slope streaks are darker than their surroundings, but not all of them are dark. In Arabia, it is common to find bright and dark slope streaks, and to find them together. This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows an example, taken from a crater near 10.5°N, 318.4°W. Why some streaks are bright and others are dark is not yet known. This picture covers an area 3 km (1.9 mi) wide and is illuminated by sunlight from the left.