Manhattan is built on a swamp, iirc. It was not inhabited by the "Native Americans", prior to Whitey showing up. I've heard the alternative story, that it's base is granite, etc. So I am not sure. But if it is indeed somewhat unsound, a Richter >5 would probably slide the buildings right off the island into the Hudson. And then the wave would take out most of New Jersey and/or Long Island.
East River. Main channel depth >100 feet.
I suppose that is deep enough for some types of submarine.
My point was that if there is a trough next to the Island, then it might mean that there is a fault there.
Experts warn NYC could come down like a house of cards if a 5.0 earthquake struck along the 125th Street fault line - and the Big Apple is OVERDUE one https://www.dailymail.co.uk/news/article-5577117/New-York-overdue-earthquake-destroy-6-000-buildings.html
This is true.
Manhattan is built on a swamp, iirc. It was not inhabited by the "Native Americans", prior to Whitey showing up. I've heard the alternative story, that it's base is granite, etc. So I am not sure. But if it is indeed somewhat unsound, a Richter >5 would probably slide the buildings right off the island into the Hudson. And then the wave would take out most of New Jersey and/or Long Island.