On March 11, 2011 at 2:46pm (JST), a 9.0-magnitude earthquake struck the north-east coast of Japan, triggering a massive tsunami killing thousands and leaving hundred thousands without a home. In its wake developed a unprecedented crisis at the Fukushima nuclear power plant which threatens to impact the lives and health of even more. Tokyo/Yokohama, the worlds most populous metropolitan area with a estimated population of 35 million is just 240 km south.

In the case of a major sudden harmful nuclear event, emergency evacuation is impossible, the disruption of public service and provisioning in such a dense populated area is very dangerous. Prudent employers and institutions therefore moved out of Tokyo, helping to relieve the city and their own staff.

However the majority of inhabitants stay. Companies are betting on the best possible outcome: ordering the office fully staffed and declaring "business as usual", protecting not just the core business but avoiding the cost of proactive employee care. In such a difficult situation, the best remaining possible protection is to monitor the environment as closely as possible and distribute emergency notifications fast and automated.

Nagios modular design and ease of integration allowed us to rapidly build such a service, monitoring Tokyo's environmental radiation data, graphing the trend, setting alert thresholds and building e-mail notification lists to work, home and mobile phones. While this is neither a technical highlight nor special in any way (its rather a quick hack), it is perhaps the most helpful monitoring we ever rely on (in addition to the existing channels: TV, public broadcast).

A Nagios plugin was written to retrieve Tokyo's environmental radiation levels published by the Tokyo Metropolitan Institute of Public Health [English URL / Japanese URL].
Implemented at our diesel-generator backed Nagios system at the office and on a private, cloud-hosted server for access from home, it is auto-alerting us when radiation thresholds are triggered.

susie112:~ # /srv/app/nagios/libexec/ -w 1 -c 2 -f
Tokyo radiation 0.131 microgray/hr : OK | time=2011-03-25 15:00~15:59;max=0.131;min=0.126;avg=0.129

nagios radiation monitoring

Of course ideally I would like to have a independent, local radiation measurement device, but I could not get one. Fortunately, the radiation is according to experts very low, not harmful and the trend this week seems to go down. We might be fortunate not having to deal with a worsening situation, avoiding decisions that are very difficult to make.

nagios radiation monitoring

Radiation is one of the most stressful dangers because it is undetectable by our human senses. It's longterm effects on health can be painful and slow. As people living in Tokyo are getting accustomed to the abnormal situation, they start to tune out. We should stay alert and not turning into resignation.

Tokyo metropolitan power monitoring

In addition to radiation, loosing such a major source of electricity has a frightening impact on a city the size of Tokyo. Immediate rolling blackouts allowed to re-baseline the power consumption and impose restrictions to ensure delivery in peak times. The government enforced a 15% power usage cut on all companies during summer month's, halting elevators and setting air conditiong at 28 degrees celsius limits. Tepco, Japans largest electricity utilities provider, started to publish Tokyo's energy consumption which has been made available through an API. Together with some Nagios 'magic', we can now have a "live" view and see how close we get to the limits. Below is a example screenshot, showing Tokyo's electricity consumption and maximum available power (in GigaWatt).

Tokyo power consumption monitoring

Tokyo power consumption monitoring graph

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