Kilauea Summit Changes

Saw this on the HVO website today. It clearing shows how the summit is changing. The Halema'uma'u vent has tripled in its opening size, plus a large area adjacent to the vent has slumped. That's a lot of rock falling into the throat. To a novice like myself, it surely appears that Kilauea is building up to a major collapse. On top of this, the entire crate floor has dropped about 3 feet. So I ask, where has all that lava drained to?