FY 2012 Repeat bathymetric surveys at 1-metre resolution of lava flows erupted at Axial Seamount in April 2011 Caress, D.W., D.A. Clague, J.B. Paduan, J. Martin, B. Dreyer, W.W. Chadwick, Jr., A. Denny, and D.S. Kelley Nature Geosci., 5(7), 483–488, doi: 10.1038/ngeo1496 (2012) At sites with frequent submarine volcanic activity, it is difficult to discern between new and pre-existing lava flows. In particular, the distribution of the fissures from which lava erupts, the routes taken by lava flows and the relationship between the new flows and the pre-existing seafloor bathymetry are often unclear. The volcanic and hydrothermal systems of Axial Seamount submarine volcano in the Pacific Ocean have been studied intensively since eruptions were detected in 1998 and 2011. Here we combine pre- and post-eruption bathymetric surveys, with 1-m lateral resolution and 0.2-m vertical precision, to precisely map the extent and thickness of the lava flows, calculate the volume of lava and unambiguously identify eruptive fissures from the April 2011 eruption. Where the new lava flows extend beyond the boundaries of the repeated surveys, we use shipboard multibeam surveys to map the flows with lower resolution. We show that the eruption produced both sheet and lobate flows associated with high eruption rates and loweruption- rate pillow mounds. We find that lava flows erupted from new as well as existing fissures and tended to reoccupy existing flow channels. This reoccupation makes it difficult to map submarine flows produced during one eruption without before-and-after bathymetric surveys. Feature Publications | Outstanding Scientific Publications Contact Sandra Bigley | Help
