LAUSR

Venus has a geologically young surface, but it is unknown whether it has ongoing active volcanism. From 1990 to 1992, the Magellan spacecraft imaged the planet’s surface, using synthetic aperture radar. We examined volcanic areas on Venus that were imaged two or three times by Magellan and identified an ~2.2-square-kilometer volcanic vent that changed shape in the 8-month interval between two radar images. Additional volcanic flows downhill from the vent are visible in the second-epoch images, although we cannot rule out that they were present but invisible in the first epoch because of differences in imaging geometry. We interpret these results as evidence of ongoing volcanic activity on Venus. Description Signs of volcanic activity on Venus Numerous volcanoes have been identified on the surface of Venus, but none has been observed to erupt, so it has been unclear whether volcanic activity has ceased. Herrick and Hensley examined locations on Venus that were observed two or three times by the radar instrument on the Magellan spacecraft when it was searching for changes between the images caused by ongoing volcanic activity. The authors identified a volcanic vent that enlarged and changed shape in the 8-month gap between two radar images and a possible lava flow running downhill from the vent. The results are interpreted as active volcanism on Venus. —KTS The changing radar appearance of a volcanic vent on Venus is interpreted as ongoing active volcanism on the planet.