Final answer:
Io's volcanic activity is powered by tidal heating due to the gravitational forces exerted by Jupiter. Over 100 volcanoes on Io spew molten silicates, and this activity is responsible for both the moon's distinctive surface colors and its geological vitality.
Step-by-step explanation:
The moon Io exhibits significant volcanic activity, characterized by more than 100 recently active volcanoes dotting its landscape. This activity leads to large flows of lava that cover approximately 25% of Io's surface with still-warm molten rock. The vibrant colors of Io's surface are thanks to a coating of sulfur compounds, but the volcanism itself is fueled by eruptions of molten silicates similar to those on Earth.
The energy source for this intense geological activity on Io is tidal heating, which is a result of Io being caught in the powerful gravitational field of Jupiter. Jupiter's immense mass exerts strong tidal forces on Io, deforming it and creating a substantial bulge that extends towards the gas giant. This constant flexing generates internal friction, which in turn heats the interior of Io, allowing it to remain geologically active despite its relatively small size.