Why does Mars have bigger volcanoes than the Earth?
Credit: Lunar and Planetary Institute The Tharsis region of Mars with a map of the western United States for scale. Olympus Mons is the volcano at upper left. Martian volcanoes are not currently active as far as we can tell but some of them must have been quite recently (at geological scale), which means about 1 million years ago or less. Are they extinct or only dormant? No one can tell with volcanoesand we are still looking for a spectral signature that could show us a region of heat on Mars. We’ll see. As you said, these volcanoes are quite big compared to the Earth’s volcanoes. Although you probably have heard a lot about Olympus Mons and all the Tharsis montes, which are really big, there are all sorts of volcanoes on Mars. Many of them are about the size of those found on our planet. Now, what the Martian volcanoes are not: they are not created by subduction which requires moving plates. Lots of volcanism on Earth happens on, or at, the margins of continental plates. Plates are m
