May 30, 2021: Open Lava Tube
Image courtesy of NOAA Office of Ocean Exploration and Research, Galapágos Rift Expedition 2011. Download larger version (jpg, 1.8 MB).
An open lava tube observed during the Galapágos Rift Expedition 2011. This collapsed feature often occurs when the outer edges of a flow are quickly cooled by contact with seawater. The insulated lava inside remains viscous and eventually recedes, creating a void.
From: Exploring from Afar.