Steaming gasses and hissing noise on many places. Very surreal.

The caldera is several hundred feet deep and it is 2 by 3 miles (or 3.5 by 5 km) across. When
William Ellis saw Kilauea 1823, the caldera was twice deeper! A lesson in geology...
Since than 0.5 cubic miles (or 2.5 cubic km) of a new lava filled up the bottom of the caldera.