This is an oblique Apollo 16 view of Alphonsus Crater on the lunar nearside (13.4°S, 2.8°W). This crater is particularly interesting because, although it was formed by an impact, it has fractures on its floor and there are symmetric dark patches around some of these fractures. The dark patches are believed to be volcanic in origin, and were most likely produced by explosive eruptions similar, perhaps, to the Pu’u O’o example shown in slide #13. Alphonsus Crater is approximately 120 kilometers in diameter. The island of Oahu, which is approximately 45 × 65 kilometers in size, has been superimposed in red for a scale comparison.
Apollo 16 AS16-M-2468.