What is the diference between the volcanos on Earth and on Mars?

Answer 1

Earth has tectonic plates and most volcanoes form on boundaries of these plates. Mars does't have moving plates.

One kind of volcano forms as plates move over hotspots under the crust. Hawaii, for example, is a chain of islands formed volcanically. If the plate that Hawaii is on didn't move, there would be one large volcano/island instead of a chain.

On Mars there are no plate tectonics, so volcanoes get to be much larger rather than forming chains of smaller ones.

Another difference is that Earth volcanoes can erupt with much more explosive force due to the buildup of pressure from steam. Mars appears to be too dry for that to be a factor, so its volcanoes never blew up like Earth's can.

Lastly, Earth has active volcanoes and Mars doesn't.

Answer 2

The volcanoes on Mars are larger than those on Earth..."Olympus Mons" is the tallest known volcano anywhere in the solar system.
However, those on mars are all inactive. The only bodies in the solar system with ACTIVE volcanoes are Earth, and Jupiter's moon Io.