Explanation:

Abulfeda is not a scary crater, unless perhaps you were standing on its west rim crest looking down a 30 degree slope to its floor 3 km below. Dont stand too close to the edge! With a diameter of 62 km, the newly-formed Abulfeda probably looked like nearby Werner, with terraces and central peak. But Abu is a kilometer shallower than Werner - a peak probably lies entombed within its crater fill material. Abulfeda is similar to many other flat-floored craters in the lunar highlands, and the question is what is that floor-filling stuff. As I have discussed before, the standard answer is ejecta from Imbrium and other basins. If the floor results from partial filling by basin ejecta, what happened to the terraces? I guess that seismic shaking by nearby and distant impacts causes terraces to collapse piecemeal until crater inner walls are somewhat lumpy but muted. Have you noticed the partial crater at the upper right with the smaller fresh crater cutting its rim? The bigger crater is the famous Descartes, and off the image to the north is the Apollo 16 landing site.

— Chuck Wood

Technical Details:
Jan 17, 2005. 18" Starmaster Newt., DMK-21F04 camera, stack of 1000 frames from 2100.

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