Part I: The Bishamon Project

A view of the Fukushima Daiichi nuclear power plant from Ukedo harbor in Namie City, about 7 km (4 miles) north of the plant


It has now been more than a year since the Great Tohoku Earthquake of March 11, 2011, but many people around the world may not be aware that there is an on-going crisis that continues to plague the country.

As one may recall, this was a triple catastrophe, starting with the 9.0 Earthquake, followed by a Tsunami, and then the cataclysmic nuclear crisis in two Fukushima Nuclear Plants along the northeastern coast of Japan.  The result of the nuclear disaster was the immediate evacuation of all citizens within a 20km radius from the nuclear plant.  To this day, not a single resident has been allowed to resume life within these confines, and will most likely not be able to return in the near future, if at all.

Namie City, inside the 20km evacuation zone, is eerily empty in the early morning rush hour (taken 12/11/2011)

Communities that were ravaged by the tsunami are slowly recovering through reconstruction efforts, but the 20km evacuation zone has become a no-man’s land, a barricaded, desolate space that has been largely left untouched and uninhabited since March 11. All entry roads into the evacuation zone are heavily barricaded and guarded; access is only allowed for those with government approved permits, and even then, entering personnel are encouraged to wear white overalls and gas masks.  Venturing inside the confines of the nuclear zone reveals that there are more cows inhabiting the area than humans.  Cows and other animals were not subject to the evacuation procedures.

Cows are seen roaming around the restricted evacuation zone

While many are contemplating next steps and strategies to revive and resurrect communities surrounding the 20km zone, a lingering question continues to trouble the populace:

How safe is it to live in these areas?

Part I:  The Bishamon Project

Professor Naito from Niigata University leads the Bishamon Project Team

In an effort to answer this question, a research team from Niigata University lead by Professor Makoto Naito, has started a project called “Bishamon”.  The word “Bishamon” is an acronym for BIo-Safety Hybrid Automatic MONitor, but also symbolic of Japanese folklore and mythology, representing one of the Seven God’s of Fortune, where Bishamon is the God of Warriors, assigned to be the guardian of places, appropriately named to protect the the people in Fukushima. The mission of the Bishamon team is simple:  to educate the citizens living around the nuclear plant on the amount of radiation that exists within their communities by providing accurate and timely data.  The team has elected to monitor areas with high concentration of school routes to address the safety of children as its top priority.

Members of the Bishamon team measuring radiation levels in Namie City, inside the 20km evacuation zone

Data Collection

What is paramount to the project is the accuracy of the radiation data being collected.  While there are other projects that rely on crowd sourced data, the Bishamon team insists on a highly regulated, tested and proven set of recording equipment and methodologies.  In order to accomplish this goal, members of the team have concocted a “hybrid” device that combines a radiation monitor, a GPS device, and a laptop equipped with a custom made application that tracks the radiation levels along with geolocational information in real time.

The Hybrid monitoring device

The hybrid device is mounted on a tray that can then be loaded onto a vehicle.  Once turned on, the monitoring application can be configured to record radiation levels by a given time interval.  For example, it can record a radiation reading every second, allowing a vehicle to drive through a community and gather accurate readings along its route by simply turning on the hybrid device.  The laptop then provides real time charts and maps as shown below.

Custom GIS application that shows radiation readings and geolocational information

The hybrid device can also be carried manually, allowing the team to walk through targeted areas such as school grounds to record readings in places that vehicles cannot enter.

Bishamon team members walk around an elementary school using the portable hybrid device to record radiation levels

The Bishamon Team began the data collection process in the summer of 2011 by employing these two methods of acquisition (by vehicle and by foot), focusing on routes that children use to commute to school.  At the time that this report was written, the data collection process was conducted over multiple trips to various communities both in and out of the 20km evacuation zone, starting on September 2, 2011 to February 12, 2012.  All in all, more than 700,000 readings were collected over this time period.

Data Visualization

Once the data is collected, maps are generated to provide a visual representation where  each radiation reading location is assigned a color value based on the strength of the radiation.   Many factors were considered in regards to the data categorization assigned to the readings.  The categorization affects the colorization of the points on the map, and the breakpoints determine which colors are assigned to the different ranges of radiation.  These provide an immediate visual interpretation of the data collected.  Red, which is typically associated with elements of danger (and usually elicits strong emotional reactions), was chosen to represent the areas of highest radiation. Green, which is typical for elements of safety, was chosen to represent areas of lower radiation levels. The map below shows one of the generated maps for the region around Ota Elementary School, located just outside the 20km evacuation zone, showing high levels of radiation (over 1 mSV/hour).

Radiation map of the area around Ota Elementary School in Minami Soma City

In contrast, the map generated for the area around Omika Elementary School, also just outside the 20km evacuation zone, shows low levels of radiation.

Radiation map for Omika Elementary School

These maps were then provided to the local governments to publish to the public.  An example of this can be seen in the Minami Soma City website where they have listed a series of maps created by the Bishamon team.