Drone footage has exposed new cracks in Hawaii's Kilauea volcano crater, and scientists fear a massive explosion could be imminent.
Boulders can be seen in the video, shot by the US Geological Society, blocking eruptive vents and stopping ash from emerging.
Geophysicist Kyle Anderson of the Hawaiian Volcano Observatory told UK paper The Express this could go one of two ways.
"We really don't know the implications of this long-term "It's possible that new explosions will blast through the rubble at the bottom of the vent. These may or may not be larger than the previous explosions.
"It is also possible that the vent may become permanently blocked, ending the explosions entirely."
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The crater has calmed this weekend, following a month of near-constant lava flows. A 12-acre lake of lava that used to sit atop the summit has emptied, the USGS said.
Residents in the area are being urged to evacuate. More than 70 homes have been consumed by lava to date.