Between 1 and 2 PM (Hawaiian time) on August 3, the floor to the Pu`u O`o crater collapsed in spectacular fashion - and luckily for us, many Eruptions readers were watching the webcams at the time and saw the event unfold. We even have a great time-lapse video of the event thanks to Eruptions reader Pgen Pgen. In it, you can clearly see the hardened floor of the crater begin to slump in the middle and over the course of 30-40 minutes, collapse into the Pu`u O`o crater. At the same time this was happening, a breach formed in the Pu`u O`o cone and a lava flow began on the flanks of Kilauea - this is typical for a spatter cone like Pu`u O`o as they are made of loosely consolidated material spit out during the basaltic eruptions of the vent. So, sometime lava will punch through a weak spot in the base of a cone and produce a lava flow, much like what we see now.
This lava flow broke out of the west flank of the Pu`u O`o cone, less than a mile from the Kamoamoa Fissure that was active earlier this year. This new lava flow effectively drained the lava lake at Pu`u O`o and has moved 3 km downslope in less than 24 hours. You can see the breakout on the cone in the image below - it does remind me of puncturing a bucket and watching the water flow out the bottom. You can also see a time-lapse of the lava flow created by Eruptions reader Raving that captures the flow as night falls.
Be sure to keep your eyes glued to the West Pu`u O`o webcam (amongst other Kilauea webcams) to see how this new activity develops. It certainly has been an exciting year at the Big Island's most active volcano.
Top left: Halfway through the collapse of the Pu`u O`o crater floor collapse on August 3, 2011.