Understanding the new “above sea level” signs


In my column in The Japan Times on Oct. 22, I wrote about the spate of new 海抜 kaibatsu (elevation over sea level) signage going up all over Japan. Each sign provides the elevation at the spot where the sign is erected.

Because there is no national standard, and many of the signs are only in Japanese, it’s a good idea to familiarize yourself with the variations. Let’s start with the sign above, in Gotsu, Shimane Prefecture. The text says ここの地面は海抜17.5 m koko no jimen wa kaibatsu 17.5 m (the ground here is 17.5 meters above sea level). Helpfully, there’s a little English and Chinese and Korean, too.

Here's what the signs tend to look like along streets and roads:


In this case, the text is ここの地盤は海抜2m koko no jiban wa kaibatsu 2m (the ground here is 2 meters above sea level).

In Tokyo, most of the signage includes at least the English words “above sea level.” Tokyo Metro’s signs have Chinese and Korean too, and are part of the subway operator’s efforts to reduce the risk of flood damage.


The example below, which is in Aioi City, Hyogo Prefecture, gives not only the elevation but also indicates the closest safe place to evacuate to in case of a tsunami. (In this case, an elementary school 490 meters ahead at 7 meters above sea level.)


To get an idea how high you’d need to go in your area for various rises in sea level, whether from a tsunami, flooding or global warming, take a look at this interactive flood map. If you live in Japan, your local government should be able to provide guidance about flood evacuation points.

Minato-ku in Tokyo, for example, recently released a free app for smartphones that can guide you to safety. It’s called 港区防災アプリ “Minato-ku bōsai apuri” (Minato-ku disaster app). Once you’ve downloaded it all you have to do is point your phone at something in your location and it will tell you the nearest evacuation point. Here are the download links for iPhones and for Androids. Versions in English and Chinese should be available in November so check back then. I’ll try to remember to update this post with links.

To learn more about rising sea level, check out Brad Plumer’s Wonkblog post, “Why Tokyo has more to fear from sea level rise than Vancouver.”

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5 Responses to Understanding the new “above sea level” signs

  1. lrherzog says:

    Interesting article, Alice.

    Love those apps!

    Hope you are doing well.


  2. Allan Murphy says:

    Good morning, Alice. I’ve been wondering about those signs and was going to write in. It is a good emergency measure – pity about the lack of standardization, though. I am relieved that our station, Senkawa, is about 30 M. Anyway, better to be in Tokyo than Miami, America’s Venice:

  3. I really enjoyed this post- thank you!

  4. TonyJ2 says:

    Alice, as an emergency services worker in Australia, I have these signs and similar disaster signs really easy to understand. The use of international symbols and arrows etc make sense even for visitors like me.

    As I travel around one of my photo themes have been these signs. And I have taken this style back to my workplace in Oz.

  5. Anon Kun says:

    Interesting post! I was in japan recently and was wondering why there were so many signs indicating the level above sea level

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