There are new alarming cracks and fault seen in a collapsed crater, some of which are spewing with intense steam.

Scientists are concerned that an "expanding collapsed crater" and the debris blocking the vent could trigger a massive explosion.

The drone footage from the US Geological Survey (USGS) shows "yellow sulfur substance on the rubble-covered floor and a scattering of large ballistic blocks around the crater rim".

USGS officials revealed that the empty vent once housed a 12-acre lava lake up until a few weeks ago.

The vent is currently empty of lava and has been stretched to massive 100-acres.