Seafloor Processes at Kick ‘Em Jenny Volcano, Pre- July 2015 Volcanic Event, using High-Resolution Shipboard and Remotely Operated Vehicle Near-Source Data
To understand the physical and geological processes that drive the volcanism and control the morphology of KEJ volcano, the only active submarine volcano in the Lesser Antilles volcanic arc, I conducted near-source, high-resolution bathymetry and magnetic mapping of KEJ volcano and its subsurface using the ROV Hercules during cruise NA054 of the E/V Nautilus (Sept.-Oct. 2014). In our results, multiple generations of submarine landslides and well-developed canyons are observed, suggesting that the area has been hosting dynamic sediment transport systems from the flank of the volcano to the seafloor at multiple scales over time, with some of them being attributed to past eruptions. The canyons likely formed from in situ gravity flows due to the lack of evidence for subsidence in the area of KEJ. Columnar basalts located in the middle of the landslide deposit are similar in appearance to those observed in the KEJ crater during previous ROV dives, indicating a possible extent of a landslide event, i.e. a travel distance of volcanic materials from the crater region along landslide path. Landslide triggers at KEJ are still debated, but sector collapse of the edifice has been numerically predicted to be the failure style. High-resolution near-bottom magnetic anomaly data is used to investigate ongoing volcanism at KEJ, and revealed a magnetic anomaly high within the inner crater of KEJ. The source of the dichotomy in magnetization is both a dike complex at the inner crater and a fault trending NNE-SSW. I propose the following cyclic evolution scenario of KEJ from eruption events to inter-eruption periods, by combining seafloor morphology observations, integrating high-resolution bathymetry maps, ROV visuals and rock samples from the wholesale KEJ, and subsurface characterization with high-resolution near-bottom magnetic survey of KEJ crater and inner crater. KEJ formed from arc volcanism; the magma rises quickly though the magma conduits to the shallow subsurface with a series of dikes; it erupted in shallow water depth; it erupted in an explosive style; these volcanic eruptions trigger a landslide and deposit material downslope; submarine canyons form from in situ submarine gravity flows until next the eruption
