M5.4 quake strikes off Ibaraki Prefecture

Mr. Flint might be on to something. If you look at the USGS map for quakes over the past 30 days, there definitely seems to be a pattern building along the Pacific coast of Japan.

https://earthquake.usgs.gov/earthquakes/map/?extent=25.20494,-239.58984&extent=47.39835,-205.26855&range=month&magnitude=4.5&settings=true

Was on the 11th floor on an old building on this one so it felt quite strong, it was good that it was short.