Transport and Deposition During The 2012 Submarine Explosive Eruption of Havre Volcano

Abstract:

Havre Volcano in the Kermadec Arc experienced a large eruption in 2012. The eruption was identified when ships in the area intersected a pumice raft, which was subsequently tracked by NASA MODIS satellite imagery. In 2015, an NSF-sponsored research cruise to the area conducted AUV and ROV dives to map and sample the deposits of this eruption. This presentation describes the high-resolution mapping data and seafloor observations that illustrate the processes of lava and pyroclast transport and deposition. The National Deep Submergence Facility (NDSF) AUV Sentry collected multibeam bathymetry data over the Havre caldera rim and floor - an area of 56 km² - at a resolution of 1m. In addition, Sentry collected high-resolution sidescan sonar backscatter data over the same area. The NDSF ROV Jason collected HD video and down-looking still imagery along dive transects. These data allow us to document the depositional landforms in great detail. Notable features include effusive domes, lava flows, and a widespread blanket of giant pumice and ash. With constraints from seafloor imagery, we use the morphology of the imaged landforms to delineate deposit extents, identify intra-flow and intra-deposit features, pinpoint vent locations, and, in comparison with pre-eruption bathymetry, determine eruptive volumes. This information informs preliminary models of transport and deposition processes that are unique to submarine explosive eruptions.