Based on "Implemenation Guides on Sea Area Monitoring in FY2013", the Secretariat of the Nuclear Regulation Authority conducts sea area monitoring to figure out dispersion, deposition and migration of radioactive substances released into the environment. Measurements of marine soil in Tokyo bay and offshore (30 - 90 km from coastal line) of Miyagi Prefecure, Fukushima Prefecture and Chiba Prefecture are conducted considering continuity with past monitoring. The data here was created based on the results of measurement. Measurement period of the KML file is from May 2013 to October 2014 .
Publicly available data collected from the website of the relevant organizations and converted into CSV, XML, and KML formats that were easy to use.