[Smokin' Joe]

If you haven't already, do a web search for "Surtsey", which formed near Iceland over the Mid-Atlantic Ridge in the late '60s/early '70s. National Geographic did a good job of documenting its formation.

Spreading centers/rift zones are another popular plate boundary for volcanic activity, but most of it is underwater.

[VlPu]

“which formed near Iceland over the Mid-Atlantic Ridge”

How comes that the official ocean relief map (used by Google Earth) indicated a depth of at least 1200 ft for the coordinates of the volcano that erupted out from the ocean?

Answer: google, result #1 says it all
http://www.google.com/search?hl=en&q=mid+atlantic+ridge+hoax