If you happen to drive east / west through Yakima on a semi-regular basis you've probably noticed the Rattlesnake Ridge slide over the past half a decade:

https://www.heraldnet.com/northwest/landslide-near-yakima-mi...

https://www.yakimaherald.com/news/local/lower_valley/rattles...

Not Japan, but the PNSN has a great article on slow slip events in the PNW: https://pnsn.org/blog/2020/09/25/silent-rumbles-under-our-fe...