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| Beautiful granular flows on the steep eastern wall of Hipparchus G crater (13.68 km; 5.03°S, 7.4°E) brought fresh debris from the rim down downslope to the left. Field of view about 1 km from LROC NAC observation M183474839L, LRO orbit 12135, February 10, 2010; 38.77° incidence angle, resolution 1.02 meters from 100.52 km [NASA/GSFC/Arizona State University]. |
LROC News System
Hipparchus G (13.68 km; 5.03°S, 7.4°E) is a high reflectance crater formed on the rim of the much older and degraded Hipparchus crater, in the nearside Southern Highlands.
While these streamers may look like mudslides, they are actually dry solids that underwent fluidized flow; these features are called debris flows and are seen in many craters on the Moon.
While these streamers may look like mudslides, they are actually dry solids that underwent fluidized flow; these features are called debris flows and are seen in many craters on the Moon.
Why do these flows look like tendrils? As the debris was flowing downhill, in some places it encountered obstacles, such as a rougher surface or large boulders. If the flow had enough energy it found its way around the obstacle, as seen by the curved path taken by these streams, if the obstacle was too large and the debris was too thin, it came to a halt.
These flows really stand out from the rest of the crater wall material because they have a higher reflectance. Higher reflectance indicates that this material has been exposed to less space weathering than the crater wall, so this flow happened long after the formation of this crater.
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| Footprint of LROC NAC observation M183474839L, from 100 km, LRO orbit 12135, February 10, 2010, This PDS projection, even on the outdated lunar DEM available in Google Earth, show the true profile of Hipparchus G, not readily discerned from directly overhead. The higher east rim, nested in the rim of ancient Hipparchus, rises 3.2 km in elevation above the smaller crater floor, may have originally brought up a variety of materials of contrasting reflectance [NASA/JAXA/GSFC/USGS/Arizona State University]. |
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| Among the highest resolution LROC Wide Angle Camera observations of Hipparchus G yet available from LRO, actually a mosaic of two sequential passes on November 16, 2010; 47.35° incidence angle, resolution 61 meters from 44 km [NASA/GSFC/Arizona State University]. |
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