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Japan Radiation Map Roundup

If you want to know what's going on, ask the nerds. As fears swelled over radiation from Japan's battered Fukushima Daiichi nuclear power plant in the days after the 11 March quake, computer-savvy individuals around the globe had an immediate reaction: show people the data. Within days, individuals began tracking down and using the data to create interactive maps and graphs of radiation levels in Japan. Here are some that have stood out as especially useful. Their sources include government monitoring stations and Geiger counters duct-taped to the balconies of Tokyo apartments, and vary in completeness and in how frequently they're updated. Neither Science nor the creators guarantee these maps' accuracy; they are meant to supplement, not replace, official formats of releasing data. These maps are works in progress, and new ones are coming online every day. If a map has caught your eye, if you're developing your own, or if you're a scientist and have found visualizations like these to be helpful, send us an email, or leave a comment below. We'll add them to this page, so check back again.

Marian Steinbach, a user-interface designer based in Cologne, Germany, noticed something decidedly user-unfriendly about media reports on Japan's nuclear crisis. "I was looking for a big picture of the situation of radiation in Japan, which I couldn't find," he says. So he started manually grabbing radiation readings from Japan's sensor network, known as SPEEDI, which is released every 10 minutes by the Ministry of Education, Culture, Sports, Science and Technology (MEXT). He put them in a format that developers could work with. Soon volunteers from around the world joined in to keep the data flowing—and translate data posted only in Japanese—until Steinbach could write a computer script to automatically "scrape" the data from the site and dump them into a readable file at intervals. Still missing, however, are continuous readings from Miyagi and Fukushima prefectures, which were hard-hit by the earthquake. MEXT is publishing readings from the latter a few times a day as a PDF that Steinbach hasn't been able to scrape—yet. Nevertheless, Steinbach's data have become a source for a growing number of maps and visualizations. "Fortunately, I have a flat fee on bandwidth," he says.

One spinoff is Norwegian software engineer Geir Engdahl's map, which displays SPEEDI sensor locations and their readings in nanoGrays per hour. (Grays are a way of measuring radiation that looks purely at the energy deposited in tissue, known as the absorbed dose.) Click on a bubble—which are color coded by magnitude—to see the most recent reading. You can also track that station's reading over the past 24 hours, week, or month to look for spikes or to compare readings before and after the earthquake:

Screen Shot: On the full-sized map, click on measurement locations to see a chart of the radiation measured from that station over time.

This map, also based on Steinbach's scraped MEXT data, gives the maximum latest values per prefecture and displays major cities scaled by population:

Meanwhile, in Portland, Oregon, Marcelino Alvarez, a self-described "news junkie and data junkie," says he "kept hearing a refrain" as he watched the news. "When the more intelligent scientists were on TV, they'd say, 'We don't have data, we don't know what's going on here.' " So he and David Ewald set to work with the developers at their start-up Uncorked Studios. Their map at ("Radiation" without the vowels) includes not only MEXT data but also data submitted by individuals with Geiger counters, and they have plans to raise money to get more instruments into Japanese hands. But as such, their data comes in a hodgepodge of units—see the Australian Radiation Protection and Nuclear Safety Agency for a good discussion of the difference between grays and sieverts.

Many Sources: This map on contains data from both official and user-submitted sources.

One source that's map pulls from is Pachube, a clearinghouse that pulls in time-series data from various sources that pushes it out into manageable feeds. "Pachube acts as a real-time databroker for a wide variety of (sensors)," says Usman Haque, the site's CEO and founder, who is based in London. Right now, they're brokering data from individuals who, like Steinbach, are scraping official data, individuals with Geiger counters hooked up to their computers, or people with hand-held detectors and a data-pushing iPhone app. (There's been a run on Geiger counters in Japan, Haque says.) Several maps have been built on Pachube's data feeds. One of the most interesting is Haque's own creation, a Google Earth layer with doses displayed as vertical towers over the sensor locations (requires a Google Earth plug-in). In some cases you can click on the data point to see its source and how the reading has varied over time.

Google Earth: Usman Haque, Pachube CEO and founder, created a Google Earth layer of crowd-sourced radiation data. You will need the Google Earth plugin (free) to properly view this map.

Software engineer Gueorgui Tcherednitchenko had personal reasons for wanting to make Japan's radiation data more understandable—he's planning to move to Tokyo, and he needed "a way to calm down worried family members," he writes in an e-mail. Motivated by "the lack of this sort of visualization in the media and [by] fear-mongering on some European TV networks," his map tries to give "some perspective on what was actually going on." He takes a sparce approach and pulls in readings from Japan's official data sources, including MEXT's data on Fukushima, by hand, to display typical doses in six major cities, with links to the source data.

Radiation levels

Radiation levels are expressed in micro-Sieverts/hour (µSv/h)

On average, a person is exposed to 2400 µSv/year or 0.27 µSv/h in normal conditions (Source: IAEA, figure can vary by several hundred % according to location)

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My map: Software engineer Gueorgui Tcherednitchenko developed this Japan radiation map to ease fears his family had about his upcoming move to Tokyo.

For our complete coverage of the crisis in Japan, see our Japan Earthquake page.  For Science's answers to reader questions about the crisis, see our Quake Questions page.