http://www.telegraph.co.uk/earth/ea...ount-Shinmoedake-volcano-in-Japan-erupts.html
Volcanic lightning is seen above Mount Shinmoedake in Japan as it erupts. It is not clear why bolts of lightning are sometimes seen within erupting volcanoes. One theory is that that the spewing magma bubbles or particles of volcanic ash are themselves electrically charged, and by their motion create separately charged areas...