Olympus Mons Summit

The circular feature near the top of this VIS image is part of the summit caldera of Olympus Mons. Scarps and extensional features (graben) record multiple stages of caldera collapse at the summit of Olympus Mons. Huge lava flows poured down the side of the volcano. Olympus Mons is the largest volcano in the solar system, reaching heights over 40 km (25 miles) tall from base to summit, with the base covering an area as large as the state of Arizona. For comparison, Mauna Loa is 9 km (5.5 miles) tall measured from its base on the sea floor.