Well,

I would put my trust in the USGS here in California. Some of the discussion else where was about newspapers and initial reports. QED is what it is. Not final. If USGS drops magnitude from 5.0 to 4.8, I would think they have adequate reason to do so, for such a small quake. If Berkeley and NCSN agree, I say that is very good reason to expect that to be the final outcome. That Lake Pillsbury was up to version 4 when I last looked. But as you say, it could change. Maybe it has to do with the geology, and only one other larger quake in the recent catalogs..PDE

Glen