A USGS geologist collects a molten lava sample during a December 2015 lava flow from Puʻu ʻŌʻō.
![A USGS geologist collects a molten lava sample during a December 2015 lava flow from Puʻu ʻŌʻō.](https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/production/s3fs-public/styles/full_width/public/thumbnails/image/multimediaFile-1270.jpg?itok=Gjvlx1L0)
Detailed Description
A USGS geologist collects a molten lava sample during a December 2015 lava flow from Puʻu ʻŌʻō. As the lava cools on the surface, its viscosity increases and the flow slows down. Credit: USGS.