The initial radiation in the form of gamma rays and neutrons can be a major source of fatalities in the first few miles from a nuclear blast of 1.8 megatons. Several factors in this scenario reduce the impact that initial radiation has on the overall number of fatalities. With the blast centered more than a mile off shore much of the lethal radiation zone is located over water where there are few people. Additionally, the heavy fog will attenuate the radiation faster than dry air, and the hills will shield many people. Since most people are inside, they will receive further shielding by buildings - typically between 10 and 40%.
