and sea floor material. Surface blasts generally produce more early fallout since the average size of the fallout particles are larger and thus fall back to earth faster. Over 300 species of radioactive materials are produced in a blast. Each has its own half life and some interact in particular ways with the human body.
If we assume that there is little wind, the fallout will settle back to earth in a circular pattern centered around ground zero. For a 1.8 megaton blast where roughly one megaton of yield comes from fission, we can expect the following total dose levels.
