This is "something", but IMO most likely not man-made. A subduction zone cannot (as far as I know) drop 3 miles in a short period of time without causing some major, and I mean major, destruction on a scale that would leave vast am mounts of geological evidence. How would it then leave structures intact?
Something like that would be millions of times more powerful than any earthquake we've ever seen.
When Alaska had the BIG ONE, they had whole sections of the city drop better than 30 feet!
It is definitely within the realm of possibilities that the damn city could drop hundreds of feet, given the size of earthquake that supposedly did away with Atlantis.
If, this in fact, for real, then it is obviously man made structures. This is well whithin the realm of nature having caused it naturally. Ever watch the programs explaining how violent the planet can be? Especially in the past. I mean Pompei certainly comes to mind.
I think you underestimate mother nature!
