Originally Posted by alan11

Neither Tokyo (Kanto) or the Osaka area are at risk for the Nankai Trough earthquake and/or tsunami. It would mainly affect coastal south east Kyushu, southern coastal Shikoku, and coastal Kii Peninsula (mainly Wakayama and Mie prefectures). It could also potentially affect Nagoya and the Shizouka area, but no tsunami wave would probably reach around to Tokyo Bay (though with a non-Nankai Trough earthquake, that'd be a different situation...) You can see a map and article about it in English here: https://www.asahi.com/ajw/articles/15383066

(and by the way, that mega-quake warning actually ended today)

The lack of rice and/or bare supermarket shelves in Tokyo, Osaka, or anywhere other than the areas listed above is either due to the limited stock of rice (particularly since its the end of season) or if it is a supermarket in a foreign tourist area, especially if near where someone would be spending their final night in Japan, because its become a bit common for people to buy a few kilos of rice to take home to their countries since imported Japanese rice is way more expensive abroad than inside Japan.

Also, Tokyo is currently being hit with a typhoon, and this was forecast several days ago and hyped up on the news as a massive event, with hundreds of flights and even the Shinkansen cancelled in advance of today, so people have probably been freaking out due to the over-dramatic headlines and have stocked up on just about everything beyond necessary.