There are numerous examples of multi-kilometre tall mountains such as Maat mons on Venus, Mauna Kea on Earth, the Tharsis volcanoes on Mars. We don't find similar such examples of volcanic edifices anywhere else. Why?

Mons Rümker is the the closest thing to that on the moon, but it is a rarity, and quite modest in height anyway.

Mercury doesn't have anything like that, all you see is pits, hollows, lava floods, etc.

I am aware that Io has a lot of relief, but these are not really volcanic edifices, but some sort of crustal deformation.

is it heat budget? Io has a lot more than any terrestrial planet. Surface gravity? Mercury's matches that of Mars.

Edit: I've removed cryovolcanic worlds from the title since I understand that cryolavas may have a harder time to build such structures, although I recall Sotra patera as an example of a modest cone found on Titan.

  • $\begingroup$ Mercury appears to be different to the other planets. It is thought to be the remnant core of a planet that was impacted by a planetesimal that stripped the crust & mantle from the original planet Mercury. Thus, very little, if any volcanic activity. $\endgroup$
    – Fred
    Oct 25, 2021 at 22:11
  • 1
    $\begingroup$ There are many types of volcanoes. Factors affecting their sizes are: the minerals in the magma & the viscosity of the molten rock, the amount of magma in the magma chamber & the pressure within the chamber - the higher the pressure the greater the force of the eruption, the higher the ejected material can go, the taller a volcano can be. $\endgroup$
    – Fred
    Oct 25, 2021 at 22:33
  • $\begingroup$ See also Why is Olympus Mons the largest volcano in the whole solar system?, which has some explanations and links about the maximum height of mountains on different planetary bodies. $\endgroup$ Oct 26, 2021 at 7:45

1 Answer 1



MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) data show that most of Mercury's surface consists of lava plains. However, no volcanoes (mountains built by eruptions) have been found to date. This is unexpected because planets and moons with lava plains also have volcanoes. We conducted a new search and found two good candidate volcanoes. We cannot be sure that they are volcanoes based on MESSENGER data. Nevertheless, the observation that volcanoes on Mercury are rare is important itself. It means most eruptions on Mercury were somehow different from those that made volcanoes elsewhere in the solar system. We suggest that most eruptions on Mercury were too large and rapid, meaning that lava spread out to form plains, rather than building volcanoes. We suggest that eruptions small enough to build volcanoes might have occurred in Mercury's later history, when it was cooler and less able to generate magma. Impact craters may have helped later magma to erupt by opening fractures in Mercury's crust. We suggest that BepiColombo, the next spacecraft mission to Mercury, should target impact craters to find more volcanoes and return better observations of our candidates.

Wright, J., Rothery, D. A., Balme, M. R., & Conway, S. J. (2018). Constructional volcanic edifices on Mercury: Candidates and hypotheses of formation. Journal of Geophysical Research: Planets, 123, 952– 971. https://doi.org/10.1002/2017JE005450

Also see: https://mobile.arc.nasa.gov/public/iexplore/missions/pages/yss/may.html


From Wikipedia:

A number of domes and cones are present on the Moon, but such features likely formed differently than those on Earth. Because gravity on the Moon is only one sixth of that on Earth, lunar volcanism is capable of throwing ejecta much further, leaving little to pile up near the vent. Instead of a volcanic cone, such lunar eruptions should form a broad, thin layer around the vent. On Earth, lava domes form from very thick, pasty lavas. Basaltic lavas are more liquid and tend to form broad, flat lava flows. On the Moon, most of the domes and cones appear to be made of basalts. As a result, they are unlikely to have formed like Earth domes from thick, non-basaltic lavas. Instead, the lunar domes and cones may mark places where the erupted basalts were just barely molten.


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