Pure luck if shooting handheld, even in a 3shot/sec. burst. Some shots are long exposure, and alot are fakes (calaboration of multiple shots)<< none posted above are fake afaik…
Most of the real good pics are actually done by video, and then a program that supports high resolution screen capture.
Very small particles of ash, concentrated together creates static on a small level.
Since the ash cloud from a large volcano often spans for miles, with an insanely dense ratio of particle:air, the static=spark=lightning. The ashcloud is a backdrop for the lightning storms, so the pictures usually look insane.
