Abstract
Safecast is a volunteered geographic information (VGI) project where the lay public collects radiation measurements via hand-held sensors that are uploaded to a central server and then made freely available. However, Safecast data fidelity is uncertain given that the these sensors are hand assembled with various levels of technical proficiency, and that the sensors may not be properly deployed. We validated Safecast data gathered in the Fukushima Prefecture shortly after the Daiichi nuclear power plant catastrophe by comparing it with authoritative data collected by the Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) during the same period. We found that the two data sets were highly correlated, though the DOE/NNSA observations were generally higher than the Safecast measurements. We concluded that this high correlation alone makes Safecast a viable data source for detecting and monitoring fallout during radiological emergencies.
