At the end of the first second, the shock wave will have an overpressure of 20 psi. at a distance of four tenths of a mile from ground zero. Even the most heavily reinforced steel and concrete buildings will be destroyed. These buildings include the Empire State Building, Madison Square Gardens, Penn Central Railroad Station and the New York Public Library. Most of the material that comprises these buildings will remain and pile up to a depth of hundreds of feet in places, but nothing inside this ring will be recognizable.
