Squeezing out mountains, mathematically, on Jupiter's moon Io

Mountains aren't the first thing that hit you when you look at images of Jupiter's innermost moon, Io. But once you absorb the fact that the moon is slathered in sulfurous lava erupted from 400 active volcanoes, you might turn your attention to scattered bumps and lumps that turn out, on closer inspection, to be Io's version of mountains.There are about 100 of them, and they don't look anything like the low lying volcanoes.