File:Fukushima 137Cs distribution from ZAMG.png

Summary
ZAMG modeled the radiation plume from Fukushima Daiichi, reporting their results as an animation (current as of 3-18-11). Their model shows 137-Cs moving across the Pacific. This image expands the relevant portion of their animation and highlights all parts of the Pacific where they ever report a non-zero concentration. (In practice, this means a concentration > 10^-3 units / m^3, which corresponds to at least 100 nSv/hr, according to their description )

This image is meant to contrast with File:Fukushima I nuclear accidents radioactive cloud-en.svg.