Answer:
Well, if you wanted to study volcanoes, you would have to get a advance degree (aka a Masters or PhD ) in Geochemistry, Petrology and/or Geophysics, or Volcanology, which is a specialized combination of the three. What you would need overall for everything is a knowledge of advance math (deferential equation, calculus, linear algebra, etc), writing skills, computer programing. Also some engineering knowledge would be helpful.