Was in a hotel in Sapporo, almost got thrown out of bed. Lot of people in the hotel lobby now.
Considering leaving Hokkaido by air if a Hokkaido and Sanriku Subsequent Earthquake Advisory is issued, don't really want to be in a potential megaquake.
Good luck, the Sapporo Chitose airport is closed for inspection of both runways.
BTW, you are safer in hotel than outside. No need to stay in lobby, go to bed, just protect your head. I experienced much bigger one in Sapporo in 2018.
Best of luck!
People were freaking about the July megaquake prophecy and nothing happened. Trying to time it is silly, just chill and enjoy your stay, you'll probably be fine.