How common are underwater geysers? Under what conditions do the form? Where are they most common?

How common are underwater geysers? Under what conditions do the form? Where are they most common?

 

 

Underwater geysers? In the sense of what we see on land as geysers I would say there are none but underwater the mechanisms that would produce a geyser produce what are called smokers where super critical water is released from the mid ocean ridges.

 

http://en.wikipedia.org/wiki/Hydrothermal_vent

 

I don't think they pulse or emit steam like land geysers but they are the same or a very similar process....