Also non-geologist, but my understanding is that the gassing is a sign of "frothing", active magma. It's the difference between boiling just water in a saucepan

Also non-geologist, but my understanding is that the gassing is a sign of "frothing", active magma. It's the difference between boiling just water in a saucepan, and boiling water and pasta - the latter will result in the saucepan overflowing. I believe that the switch in out-gassing behaviour suggests that the magma viscosity and gas levels have hit a critical point that means that the field is more likely to erupt.