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If you're enjoying this, consider subscribing — we explore questions like this every week. On Earth, our tectonic plates are in constant motion. When a hot spot in the mantle begins feeding a volcano, the plate moves over it. The volcano goes dormant as the crust moves away from the heat source. And the hot spot keeps building a new volcano on the new section of crust above it. Mars is different. Mars has no active tectonic plates. The crust is thick, cold, and essentially stationary. So when a