As you probably already know, there are a lot of natural disasters in Japan. Fortunately, they aren’t always catastrophic, but they can be, as with the Tohoku earthquake and tsunami on March 11, 2011, memorialized as “3.11” (san-ten-ichi-ichi), like 9/11 in the US.
Here are some apps, websites, and other sources that are available in English (and, in a few cases, other languages):
NERV Disaster Prevention App
You just can’t talk about this subject without mentioning NERV (特務機関NERV). Available on iOS and Android, in both English and Japanese. Free to use, with a couple of paid tiers with extra options.
NERV was created in the aftermath of 3.11. Even if you use nothing else in this post, just make sure you have this one. It has interactive maps, notifications, etc., and can even be used as a normal weather app with a rain radar as well.
They’re vital in Japanese, but I would argue that they’re even more vital in English, when official sources often only have limited information available outside of Japanese, especially with regard to localized information. I assume there’s a lot of machine translation involved here, too, but I feel this should be less problematic in their particular format.
They’re also on Mastodon with a whole bunch of accounts with posts on specific types of disasters or specific regions, but I believe this is in Japanese only. I think they also still post on Twitter in both English and Japanese, but I would really recommend installing the actual app.
See their About page for more information about the app. There’s also a really extensive FAQ here.
Multilingual portal by NHK
Information about living in Japan (including disaster preparedness) in 20 languages1 + simple Japanese by NHK, the public broadcaster (radio and TV) in Japan. Section in English here, live streaming TV here and radio here. More information about their multilingual radio service here, including news podcasts.
NHK WORLD-JAPAN app
I haven’t used this myself, but they also have an app available on mobile devices (iOS and Android) as well as TV devices (Fire TV, Roku, Apple TV, and Android TV). This should be a better option than NERV if you need information in a language other than English or Japanese (19 languages2 including English), and probably also good in English if you want further details in addition to what’s available on NERV’s app.
VoiceTra
I haven’t used this, either, but apparently it’s a real-time speech translation app (33 languages3 including Japanese) by the National Institute of Information and Communications Technology. Available on iOS and Android.
Japan Meteorological Agency (JMA)
The website is honestly really awkward to navigate (typical Japanese government website), but there’s a ton of important official information straight from the horse’s mouth. A lot of it is also available on NERV’s app in a much more user-friendly format, which is why I recommend it so highly.
The Local Information section has information for specific regions or cities, and if you click on “Local information” in the header, you’ll see a menu with other useful pages. I see that some of their maps only have locations labeled in Japanese, though, so once again, I would recommend using NERV’s app.
MLIT Disaster Prevention Portal
Directory by MLIT (Ministry of Land, Infrastructure, Transport and Tourism) with a bunch of links to other essential websites, including where to get updates on lifeline services, how to get help as a disaster victim, local government websites, etc.
It’s extremely useful, but there are so many links that you probably aren’t going to want to sit there and sift through them right when you’re experiencing the disaster in real time. I would recommend skimming through and picking up links that are likely to be relevant for you when nothing’s actually going on, so this is more for people who live in Japan, although there’s also information for tourists.