Part of the wall of the Halemau'uma'u crater of the Kilauea volcano in Hawaii, collapsed on Sunday, setting off the explosion seen here and making lava waves.
The United States Geological Survey (USGS) says, “For scale, look at the left side 3/4's up from the bottom and you will see a tiny white thing. It's a 5' [1.5m] tall USGS camera. It sits right at the rim of the crater where the public viewing area use to be.”
Some of the boulders falling around the rim are “the size of bowling balls and even ovens” the USGS says, noting that the lava lake is 520 feet (160 m) by 690 feet (210 m).