A long eruptive history
The Jovis Tholus shield volcano is located roughly in the middle between Olympus Mons and Ascreus Mons. It lies on the very northern edge of the lava plains surrounding the Tharsis Montes and is also bordered by the the Ceraunius Fossae fault system to the northeast and the Ulysses Fossae faults to the southwest. The about 1 km high volcano has a diameter of 58 km and shows a large off-center caldera complex some 28 km in diameter. It shows signs of a long eruptive history, because the caldera contains no less than 5 craters. These calderas align interconnected southwest from the first, the central caldera. Each younger caldera has a slightly lower floor. Like most tholi, Jovis Tholus is surrounded by younger lava flows, obscuring the original relief. These lavas also cover a set of buried graben which can be spotted all around the volcano. The eastern flank of Jovis Tholus is formed by a steep scarp of a north-trending graben. Some portions of this graben are exposed for several kilometers further north into the plains, however often buried by volcanic plains material. At closer look, individual lava flows can be found all over the plains.