Calderas
Olympus Mons, Mars

CALDERAS
Six overlapping caldera (1 is the oldest, 6 is the youngest) formed over time on the summit of Olympus Mons. Caldera size decreased over time, with the smallest caldera being the youngest. The youngest caldera also appears to be the deepest. This suggests that the available magma supply dwindled over time.
CONCENTRIC GRABEN
Concentric extensional fractures and graben formed within some of these caldera when their floors sagged downward. A set of compressional wrinkle ridges also formed near the center of the caldera at the same time.