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    Plates and probability

    The government has some important information for us Japan-dwellers:

    The government’s Earthquake Research Committee has compiled a nationwide “map of earthquake risk,” which indicates through different colors the probability that different regions will be visited by a severe earthquake. The map was released on 23 March. Areas in which it is believed there is at least a 26% chance that an earthquake of a weak 6 JMA or above will occur in the next 30 years (equivalent to once in every hundred years) extend across 24 prefectures from Tokai to the Kii Peninsula, centered around the Pacific coast of Shikoku.

    These things are probably useful to seismologists and insurance companies, but they don’t seem to be much more than dark entertainment to us laypeople. After all, what’s most meaningful to people in Fukuoka is that there’s a 100% chance there was an earthquake of a weak 6 JMA or above this weekend. That no one expected it to happen there rather than, say, here in Tokyo doesn’t count for a whole lot.

    Indeed, if you prefer to bet on precedent and let your math be a little dodgy if need be, the last ten or so years would seem to indicate that the next major earthquake is likely to hit somewhere outside a hot zone. Hokkaido and Miyagi Prefecture have had their expected high-magnitude quakes recently; Japan’s other severe ones have been in places such as Fukuoka on Sunday, Niigata last autumn, and (of course) Kobe ten years ago.

    What all this indicates is something that should be fairly obvious: Japan is a row of volcanic islands along a major plate boundary. Some of the volcanoes are still active. (Ooh, speaking of which: Atsushi and I went up to the crater of one on Kyushu over the weekend. I’d upload a picture or two, but I’m apparently not posting my graphics files properly to avoid chewing up bandwidth. Once I figure out what to do, I’ll post them. I tell you, sometimes nature is almost as cool as a Jerry Bruckheimer movie.) That means that, pretty much wherever you are in Japan, you’re somewhere that’s at risk of a serious earthquake, and you need to plan accordingly.

    2 Responses to “Plates and probability”

    1. John says:

      When I lived in Japan, I always used to carry water purification tabs and one of those mylar foil reflective blankets that squeeze into a box the size of those tissue samples that street touts hand out. Oh yes, and the other set of tablets to take the iodine taste away after the water is pure. I carried them everywhere I went.

    2. Sean Kinsell says:

      Yeah, I should really be better about being prepared when on the go. The apartment is tricked out fine–I have water and tuna and Calorie Mate and the fixtures that keep your bookshelf from toppling on your head. When I’m out and about, I generally just make sure my cell phone is always within reach. Given that cell phone connections are often knocked out after an earthquake, that’s probably kind of stupid.

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