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Harmonic tremor usually occurs during an eruption.

The preceed it, denoting the magmatic movement upward into a magma chamber.

While your avg depth estimates are interesting, they are still in the very shallow category, considering that they are in the interior and any magma would be coming from deeper. The zone is not along any known or identified fault.

Again, volcanology has progressed significantly as well as recognizing seismic signatures of volcanic activity. So far there is nothing to indicate magmatic movement, only normal faulting based upon regional extension.

Thanks for the reference. Harmonic tremor is sometimes but not always associated with magma movement. From the same link you sent me there is also a discussion and graphic of "Shallow Volcanic Earthquakes". For reference, here's the graphic:

Now, this is by no means diagnostic, but I've been clicking around a bit on the USGS siesmology site and comparing some of the recent larger tremors in the swarm to this graphic. Many of the waveforms appear to conform to the "shallow volcanic" sample. For instance, check out the siesmogram of Event nn00333644 from earlier today: