magma in a shallow reservoir beneath the summit drains into the East R

As magma in a shallow reservoir beneath the summit drains into the East Rift Zone, the ground above it sags, cracks and subsides. The Halema‘uma‘u crater has dropped about 400 m (1300 ft) between early May and late June. Inward slumping of the surrounding Kīlauea Crater floor has doubled the diameter of Halema‘uma‘u. The large flat block visible inside the enlarged Halema‘uma‘u is a down-dropped piece of the crater floor. View is toward the southwest.