Likes! I do think you could have bolder colors, however, and shading on the lower parts of the volcano, just so the viewer can compare the gray of the shading to the contrasting color, Y'no? Just to shake things a little. I love the handwriting there, very indie, but I think it should have been a little lower in my opinion.
As Jenth said, you could add gray stuff around to show the contrast. And bolder shades would be good. Besides that, the squarish pieces of color remind me of colourful spices, but I do think you could add small blob-like things that burst out as well.
Anyway, good job.Keep drawing. Cheers, ~Lava
~ Pretending in words was too tentative, too vulnerable, too embarrassing to let anyone know. - Ian McEwan in Atonement
One thing that I think would make this even prettier is if you varied the thicknesses of colors! Right now, it's kind of uniform, which makes it seem strange, because if there was a volcano of color, you would expect it spewing out thing non-uniformly. This can be difficult with pens, but you can use more pen strokes to achieve this illusion.
Good luck!
Ubi caritas est vera, Deus ibi est.
"The mark of your ignorance is the depth of your belief in injustice and tragedy. What the caterpillar calls the end of the world, the Master calls the butterfly." ~ Richard Bach