What are the surface conditions like on IO?

The surface is almost completely lacking in impact craters and is covered in smooth plains dotted with tall mountains, pits of various shapes and sizes, and volcanic lava flows. Io's surface is covered in a variety of colorful materials (leading Io to be compared to a rotten orange or to Pizza) from various sulfurous compounds.The lack of impact craters indicated that Io's surface is geologically young and volcanic materials continuously bury craters as they are produced. This was confirmed by at least nine active volcanoes.