Olympus Mons vents over a long period of time (The Hawaiian Islands exemplify similar shield volcanoes on a smaller scale – see Mauna Kea). Like the basalt volcanoes on Earth, Martian basaltic volcanoes are capable of erupting enormous quantities of ash. Due to the reduced gravity of Mars compared to Earth, there are lesser buoyant forces on the magma rising out of the crust. In addition, the magma chambers are thought to be much larger and deeper than the ones found on Earth. The flanks of Olympus Mons are made up of innumerable lava flows and channels. Many of the flows have
Doom Mons Titanean "mountains" are little more than hills. However, some of these mountains rise to some several hundreds of meters high. Doom Mons is currently believed to be possibly the largest Titanean mountain range and with the eponymous peak one of the highest; the title of highest peak on Titan is thought to be held by the Mithrim Montes, which may have been formed by global contraction. Doom Mons is believed to be a twin-peak that rises above the relatively flat surrounding plain, and a probable massive cryovolcano. It has a 500–600 m deep indentation on its western side, containing a