I came to post on these but you beat me to it. Have you seen that there are now two that are > M 4? The San Andreas fault comes right through here...and also there is a big geothermal energy plant extracting and injecting fluids right there...
Bears watching....someone more ambituous might want to plot time vs numbers of earthquakes at different magnitudes for this and previous swarms in the area...so that we can see visually whether this is unusual or not...

Chris