Yellow: Fireball (0.56 miles wide, 1.03 miles high) — In the area closest to the bomb's detonation site, flames would incinerate most buildings, objects, and people.
Green: Radiation (1.24 miles wide) — A nuclear bomb's gamma and other radiation are so intense in this zone that 50% or more of people die within "several hours to several weeks," according to Nukemap.
Blue-gray: Air blast (4.64 miles wide) — This shows a blast area with 5 pounds per square inch of pressure, which is powerful enough to collapse most residential buildings and rupture eardrums. "Injuries are universal, fatalities are widespread," Nukemap says.
Orange: Thermal radiation (6.54 miles wide) — This region is flooded with skin-scorching ultraviolet light, burning anyone within view of the blast. "Third-degree burns extend throughout the layers of skin and are often painless because they destroy the pain nerves," Nukemap says. "They can cause severe scarring or disablement, and can require amputation."