Except for the volcano itself, everything is rendered with pen. It's not really that hard but I thought the design and concept would be interesting, so I made this project.
Thumbnail made by me. It sort of works on the same method as @lnfernous's confetti effect, but mine uses cloning instead of rendering, and particles come out from one area. I couldn't really think of a good test account, so this is the only account I actually use. :P