Magma could be pushing up from deep below.
I think you right. There’s a very recent basalt flow 3 mi SSW of the quake swarm, and the Aurora Crater cinder cone is 8 mi. to the SW. Keep your eyes peeled for fire fountains!
My first thought, too. Tahoe is, after all, a volcanic caldera and not that far away and Mammoth/Long Valley, isn’t far either.