Concerned with the lack of understandable information in the current situation, the Institute for Information Design Japan is collecting all available measurements to compile a consistent and comprehensive Japan Radiation Map.
Most of the data used are updated hourly, however some sources provide data in larger intervals or require manual transcription; in this case we can not guarantee regular updates.
We do intentionally refrain from using any interpretative elements - such as thresholds or advisories. This needs to happen somewhere else with more competent people involved.
Measurements are interchangeably provided in Grey/Sievert units at the source. Here all measurements are given in the nano Sievert/hour (nSv/h) measure - following the simplified equation where 1 Grey (Gy) = 1 Sievert (Sv).