Fragments from that area can be found a mile away or more.
According to visitors to the area fragments of those blocks are scattered about like seeds.
It was a major event. Look at pictures of the site.
An extremely severe one, or more likely a flood of biblical proportions.
People would have know about that in NewYork never mind a dozen miles away.
No ordinary earthquake, but the area is known for many heavy earthquakes, and the strongest earthquake ever recorded was in Chile, 1960 (9.5 on the Richter scale). People were even killed on the other side of the Pacific.
These people have experienced many earthquakes and many strong ones throughout history. You should see the effect of some of them on the coast or on the mountains. They are used to it but of course not happy with it.