Fumarole

These blister-like fumaroles are vents for steam and volcanic gasses that cycle through stages of accumulation and release in hidden chambers deep beneath the ocean floor.

The gas mixture emitted by a fumarole typically contains carbon dioxide, sulfur dioxide, and hydrogen sulfide, sourced directly from bodies of magma. The vibrant, violent explosions seen here get their distinctive purple hue from the additional presence of gaseous iodine in the mixture.