Okay...

Just a quickie. This didn't take a lot of effort. Took something like RobA's mountain tutorial, then used a burn tool to hollow out a crater at the top. Messed a bit with the side, and added a low-depth noise bump map, then created a bump map from the gray-scale image.

Added a second layer of colors for the lava with yellow and oranges and reds blended and blurred a little.

I can provide a more detailed process if requested... but it's far from perfect, just a quick test to see if the concept works.

quick volcano.jpg