Here is a Map of Japan showing the Nuclear Sites around the country, most of which are Nuclear Power Plants. The Fukushima Daiichi plant which suffered the meltdown and radiation release can be seen on the east coast of the main island of Honshu, about 150 miles northeast of the Tokyo/Yokohama metro area.
= Nuclear Site Alert Level = 3 consecutive minutes of lesser of 100 CPM or 2.5 times a Station's baseline
*Readings not Equalized means the Monitoring Stations are broadcasting the raw radiation count from their Geiger counters, without adjustment for different count rates existing between various Geiger counter designs. For instance, models built around a "Pancake" (see Map Legend) style of Geiger-Mueller tube typically have a 3 times count rate over Standard tubed models.
Our network has a handful of Monitoring Stations in Japan, some running 24/7, and others intermittently, including a few in the Tokyo/Yokohama metro area, a couple closer to Fukushima, as well as a station in Sapporo on the northern island of Hokkaido. More recently, one of our Alaskan based stations, whose operator travels frequently by plane, can be seen from time to time in Japan. As compared to the standard tubed Geiger counter models used by most of the permanent stations in Japan, he operates the higher count rate, pancake tubed PRM-9000, so on average, his reading will be about 3 times more.
Below is a static image of the Radiation Map showing an Inset focused on the Fukushima Nuclear Power Plants on the northeast coast of the Island of Honshu, with Tokyo to the south for reference.
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