Safety tips that will help you in the case of an emergency
Japan Tourism Agency provides international tourists in Japan with information about safe travel. This website is available in languages including English, Chinese (Traditional/simplified) and Korean.
If you are a tour guide for international tourists in Japan, it is better to bookmark this website or use the app so you can handle an emergency situation.
Safety tips for travelers by Japan Tourism Agency
The disasters expected to happen in Japan
Since Japan geographically lies on a collision point of tectonic plates, the movements of the plates often cause earthquakes. Though most of those earthquakes are as small as you can sense little, large earthquakes may occur once in a certain period (every several hundred years etc.), and they hit different regions of Japan depending on which of the plate moves.
Thanks to the efforts by Japan meteorological agency, the mechanism of earthquakes is getting revealed, and the measures against prevention and mitigation have been improving. The efforts by Japan meteorological agency can be found on their web page (PDF)
In many cases, earthquakes involve Tsunami as Japan is islands. Large earthquakes occurred in other countries may also cause Tsunami which may reach to Japan. Information on the mechanism of Tsunami can also be found on the website of Japan meteorological agency "Tsunami Warnings/Advisories"
Japan is volcanic islands. Mamy of tourist spots in Japan, include Mt.Fuji, are located near or on active volcanic mountains. Although Japan Meteorological Agency has been observing volcanic activities, people going up to such mountains should check the hazardous situation beforehand.
Volcanic Warnings by Japan meteorological agency
If you have a plan to go for a mountain hiking and need some safety tips, see this article on digi-joho "Hiking in Japan"
Because of recent global warming or some other reasons, we tend to have sudden, heavy rain more frequently than before. Such sudden downpour, called Guerrilla-gohu or torrential rain, is dangerous while hiking in the mountains.
The information on sudden downpour is also found on the digi-joho "Watch out for the torrential rain - Guerrilla-gohu and Oh-ame".
Avalanche (Nadare snowslide)
In Japan, avalanche risks rise between late February and early April.
This NPO offers information on Avalanche (Nadare in Japanese).
Japan Avalanche Network
If you operate Skiing-related business in Japan, consider being a member of these NPO.
Other "natural disaster" you may encounter while traveling in Japan
Watch out for dangerous insects and animals. These are not actual natural disasters, but they are all caused by changes in the natural environment of Japan.
In the mountains: Hornets, Ixodid ticks, Bears etc.
Related article on digi-joho "What to know about hornets (Suzumebachi) in Japan"
In the sea: Blue-ringed octopus and other toxic fishes began to live in the sea around Japan while the climate is warming.