The Long Valley Caldera is a bit north of China Lake. Long Valley does have a huge magma reservoir beneath and is as dangerous as Yellowstone. Mammoth Mt. is on the SW side of caldera. Mammoth is dormant, not extinct. There are still hot springs in the area. Perhaps the magma from this system has found a weakness and is migrating south towards China Lake. That's what I think, but I am no real geologist.