Book related: Read somewhere that the Rock of Gibraltar is at risk of hiving off a great slab, and that if that happens it'll cause tidal waves to strike the eastern seaboard of the US. Anyone know where to find info on this? Google turns up zip. Thought I read it in "The World Without Us" but can't find a ref in the glossary. Apparently geologists have been petitioning govts to address the issue for a while. Anyone?