Happens all the time in CA, only there's people livin' along the coast that slides into the ocean.
Out here, it's just a little bit of slippage on a side slope. The cap rock slippage is a pretty good explanation.
That is a fair to middlin' big'n though.
I guess that's one advantage of livin' down on the flat lands. Them mountains do all kinds of weird things when you ain't lookin'.