Hypothetical question: If I have a fairly large island (say, the size of Vancouver Island) and pop it out of existence entirely (to, about five or so meters below the sea level), I'd assume there's be a tsunami of sorts. How large would such a tsunami be, and what factors would influence it? For example, would it make a difference to have the island pop out of existence in the deep ocean, or a shallower ocean section?
The island would be removed within a matter of moments/instantly. I was wondering about this after watching a documentation about how tsunamis were triggered after the ocean refilled the crater of the asteroid that supposedly killed off the dinosaurs.
EDIT: The island would be mostly made of sedimentary rock. There'd be some sand on the beaches, of course. I think England or Ireland would be a good match