Hi Don - I don't think those quakes are on the Hilton Creek Fault - (at least from the sources I've talked to) - there has been much activity over the past couple of years in that area and it is on some un-named fault - if you notice the line of the quakes it formes a line rather north east/southwest which is a little unusual.

I don't know if anyone has gone hiking up into the area to scout around - its behind the McGee campground area up into the sierras.

Canie