Volcanic fireworks

What with volcanoes being suddenly en vogue, here's a spectacular photo of another volcano, whose pyrotechnics include flashes of lightning. The latter are, apparently, a fairly common phenomenon - possibly caused by static charges formed from friction between the particles the volcanic mouth spews out at great speeds.

Tavurvur Spews Lava, Papua New Guinea. 

Source: National Geographic. Photograph by Olivier Grunewald