This is one of the best English language disaster preparedness portals available: http://www.pref.iwate.jp/kokusai/27900/29058/index.html It has links to English information from the Japan Meteorological Agency, what to prepare for an emergency, how to live in an evacuation shelter, and a printable disaster preparedness booklet.
In a disaster, you may not be able to access the internet, and you may not have free access to food and water. You should print out a disaster preparedness booklet, prepare emergency goods, and look up the evacuation points and shelters closest to you.
Oshu city`s official disaster preparedness website is here (Japanese only). http://www.bousai.city.oshu.iwate.jp/ Here, you can see information including alerts from the city (市からの知らせ), information on damage (被害情報), information on weather （気象情報）、how to stay prepared in everyday life (平常時の防犯)、and seeing information on floods and evacuation shelters on a map (地図表示). (See the picture at the bottom of this page.)
If you have a smartphone, please consider downloading the “Safety Tips” app. It gives alerts for earthquake early warnings, tsunami warnings, and other weather warnings in English, Japanese, Korean, Traditional Chinese and Simplified Chinese. (Be sure to turn on “automatic location setting” so the app will continue to update your location. If automatic location setting isn’t turned on, and the location isn’t manually reset for a month, the app will stop giving updates.)