Monday, March 28, 2011

Disaster Information

Disaster preparedness is on people's minds these days. Flashlights, first-aid kits, helmets, water bottles and the like are flying off the shelves all over the country. But information is as important as disaster kits, and good information can make the difference between life and death.

The best source I know of for information on natural emergencies in Japan is JMA, the Japanese Meteorological Agency. They have several pages for disaster information in English as well as Japanese:

Earthquake Information with maps showing the epicenter and Shindo strength - effect on the surface - for any recent quake.

The Tsunami Information page shows warnings on a coastline map. Just note that tsunami effect is inherently difficult to predict and the effect can vary quite a lot depending on the local situation.

The typhoon1 season will begin in another couple of months. The JMA Typhoon Forecast page is a good place to keep on top of things. With the horror of the Tōhoku disaster still unfolding, it's easy to forget that typhoons are collectively more dangerous, and take more lives, than earthquakes do. If there's a typhoon on the way, don't ignore it and don't take it lightly.

The effects of Volcanic Eruptions are not as widespread as quakes or tsunamis, and liable to happen only in specific active areas. They're not the same level of risk as the other events; nevertheless, if you live near an active area, it can be a good place to keep up with developments.

Extreme weather early warning will alert you to heatwaves and other potential dangers. Dust storms from the asian mainland and pollen levels (Japanese, external site) can be dangerous if you're asthmatic or frail, and can be a major nuisance for everyone.

You'll get tsunami and typhoon predictions through those links above. That's sufficient for typhoons that unfold over days, but you're not likely to check the tsunami page in time unless you know a big quake has just happened, and the quake information above is only updated once a quake has already occurred. Wouldn't it be good if you could get an earthquake warning before it even happened? Nowadays you can.

Japan has a well-developed earthquake early warning system run by the JMA (English info on the warning system here). Seismometers detect the first, fast pressure wave from an earthquake (think of it as a sound), and the system determines the likely epicenter, strength and remaining time until the destructive main wave hits. The data is sent to clients such as factories, hospitals and railways, to radio receivers and to television, radio and phone companies that in turn relay warnings to the public.

You can get ten seconds warning or more in the best case, but even a few seconds can make a huge difference. In the Tōhoku disaster there were no deaths among train passengers or crew, as all trains hit the emergency brakes and stopped before the quake struck them. Factory machinery can be turned off, chemical processes stopped, gas lines can be closed and surgery and other dangerous work can be halted. Imagine the difference between standing on a ladder or standing on the ground when an earthquake hits. And as bad as the Fukushima Number One nuclear accident is, it would have been much worse had reactors there and elsewhere not already started emergency shutdown at the time of the quake.

NHK will immediately interrupt its programs for earthquake warnings2, and you can buy radio receivers that pick up the emergency signal. But they depend on you watching TV at the time, or being at home to hear the warning. NTT Docomo and other mobile networks have started sending alerts through the SMS message systems. Some recent feature-phones have applications to receive these alerts and warn the user, but many older phones do not, and no smartphones have them. Of course, smartphones can easily download any kind of app, and not surprisingly there's apps for this too.

Xperia X10
Xperia X10

A good application I use is Namazu Alert. It's free, and unlike most earthquake apps it can receive and decode the early warning messages, so you get a warning before the quake hits. You can set the minimum intensity as well as the minimum Shindo level for your alerts, and set it to only warn for quakes within a maximum distance from you. It can wake the phone and ignore silent mode if you want to be sure always to receive an alert. It'll show you all quake details and plot the epicenter on a map for you.

In practice you'll probably want to set the magnitude to 6.0 or more, and Shindo to 4 or 5; you'll sometimes have several quakes per day weaker than that, and you're unlikely to even feel them unless you happen to live fairly close. Television warnings happen only with a projected Shindo strength of 5- or more.

Some people complain that the app drains their battery. It seems that if the app can't receive push SMS notifications it will fall back to polling a website, and that eats your battery. On my phone (an Xperia X10) I had to go to the settings in the Messages (that's another name for SMS) app and set it to allow push notifications from my network provider. This app will of course only pick up Japanese earthquakes, and will only work with a Japanese mobile phone provider.

It seems to run fine; I've had it for several days now and it has warned me for the recent larger aftershocks at the same time as the NHK alerts. It doesn't seem to impact my battery life at all, so it's an easy choice to just have it running. If there's anything I'd wish for it would be to set two levels of alerts. One for smaller, faraway quakes, that I'd set to only alarm if the phone is awake and not on silent mode; and one for large, close quakes that would alert us no matter what, no matter when.
If you live in Japan and have an Android phone, this seems like a very good addition to your software library. Without a phone, the websites listed above still give you lots of good information on unfolding events.

#1 What's the difference between a typhoon and a hurricane? The name. They're both tropical cyclones but called called typhoons in the Pacific, and hurricanes in the Atlantic. Also, hurricanes get human names while typhoons in Japan simply get numbered in sequence every year (though other south-asian countries give them generic names too).

#2 Other channels, not so much, unfortunately. Here's a Youtube video showing six national TV channels when the earthquake hit. NHK, the public broadcaster, is upper left. It's kind of depressing how long takes before any of the commercial channels interrupt their programs. They completely ignore the early warning and only show any information when the quake has already hit.


  1. "Yurekuru" is a similar app for iPhone:

    I downloaded it a few days ago, after having repacked my earthquake rucksack, replenished stores of bottled water, canned food, and instant noodles, bought a solar iPhone charger, and replaced the batteries in every torch in the house (on the day after the quake, when there were still batteries in the shops). There's nothing like a massive disaster in another part of the country for making you realize how unprepared you are yourself.

  2. Great as always, thanks for the insightful info!


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