Io Has Tides Like Earth, Only They're Stronger And Made Of Rock
The most volcanic known object in our solar system, Io, is a moon pockmarked by active volcanoes and lakes of lava. Its surface is constantly pulled to and fro by the gravity of Jupiter's other moons and the huge planet itself. These forces result in solid ground tides, which heave the ground up and down depending on where Io is in its orbit. The moon's "tidal bulge" can shift in height by up to 330 feet (100 meters).
from Crash Course
Key Facts In This Video
Jupiter's largest moon, Ganymede, is bigger than the planet Mercury. (1:14)
Io is the most volcanic object in the solar system, with more than 400 active volcanoes. (3:31)
Many scientists believe that Europa could harbor life. (6:26)