Why can volcanoes grow larger on Mars than on Earth?

The reason why volcanoes can grow larger on Mars than on Earth is due to the absence of plate tectonics. On Earth, the lithosphere is divided into tectonic plates that move and interact, which affects how and where volcanic activity occurs. When a volcanic hotspot forms, the movement of tectonic plates can lead to the creation of smaller, less massive volcanoes over time, as the plate shifts away from the hotspot.

In contrast, Mars does not exhibit active plate tectonics, allowing volcanic activity to be sustained over a much longer period in a single location. This lack of plate movement means that when a volcano erupts on Mars, the lava can accumulate and build up in the same spot without being disrupted. As a result, volcanoes on Mars, like Olympus Mons, can grow to be significantly larger than any volcano on Earth because they can continuously build on their own structures without being relocated by tectonic movement. This geological stability enables the growth of massive shield volcanoes that can reach extraordinary heights.