US Geological Survey (USGS) drone captured the scenes showing the dramatic drop at the summit of Kilauea.
At its deepest point, the Halema’uma’u crater is 300m (1,000ft) below the crater rim.
Scientists report the crater at the volcano’s summit has nearly doubled in size since the eruption of Kilauea began on May 3.
The events at the summit have dramatically reshaped Halema’uma’u and the crater floor has subsided at least 100m (300ft) during the past couple of weeks.
A spokesman from the USGS Hawaiian Volcano Observatory said: “Clearly visible [in the video] are the steep crater walls that continue to slump inward and downward in response to the ongoing subsidence at the summit.
“The deepest part of Halema’uma’u is now about 300m (1,000 ft) below the crater rim.”
Overnight from Tuesday into Wednesday, ongoing subsidence at the summit and large rockfalls from the crater walls were detected.
The summit of Kilauea erupted early on Wednesday, showering communities near the volcano with ash, the Hawaii Civil Defense Agency said on Wednesday.
The summit explosion produced an earthquake with a magnitude of 5.4 at 3.39am HST (2.39pm BST) and produced a plume which rose 7,000 to 8,000 ft above sea level.
The quake was followed by another explosive eruption at the summit and the accompanying ash plume rose to around 5,000 feet and drifted southwest bringing possible ash fall downwind, the USGS said.
The volcano has produced hundreds of moderate earthquakes since it first began erupting on May 3, caused by magma draining from inside the volcano and moving underground.
Along with the summit explosions, lava has been spewing out from a six-mile stretch of fissures, 25 miles down its east flank.
The most active fissure – Fissure 8 – continues to pour into the ocean at Kapoho Bay, producing a hydrochloric acid mist called “laze”, formed when lava enters seawater.
The Civil Defense Agency said: “Gas emissions from the fissure eruption and at the ocean entry continue to be very high.”
Fissure 8 continues to feed a fast moving channelised flow entering the ocean at Kapoho.
Lava fountains are reaching heights of 130 to 140ft and there is a large steam plume at the ocean entry where lava is flowing into the water at multiple points.