Thanks, Jo. Yes, it does have luminosity. Three layers (red basic and 2x orange, blended by 2 voronoi scales near the down ends, where the lava cools and the black crust appears). This might be 'cool' if I'd make some better flow maps in World Machine, as this just drawn in PS, and the terrain acts upon that. I couldn't have done his without working in the node network.
I changed the overall appearance to a more frightening one by adding an orange-brown cloud and leaving out shadows from surfaces. Low res for now.