Spent a week or so in my free time doing some R&D for getting a decent looking Lava simulation in Houdini and then bring it into Unreal.
The Lava itself is a 140GB Alembic with baked temperature & noise attributes which drive the material in Unreal Engine.
The Gas simulation is driven by the lava sim in Houdini and then exported as a VDB for use with SVTs in Unreal Engine.