text: what is the most common volcano on mars?   responses without sources aren't answers, just opinions.  i believe that each volcano on mars is unique, and therefore one of a kind, thus there is no most common volcano on mars.  as far as the most common type of volcano, it could be a shield volcano.  from wikipedia: there are several extinct volcanoes on mars, four of which are vast shield volcanoes far bigger than any on earth. they include arsia mons, ascraeus mons, hecates tholus, olympus mons, and pavonis mons.