Jennie Mowatt
Investigating the geological evolution of Rumble II West Volcano Using EM 300 Bathymetry and TowCam Imagery
The Kermadec arc, a hydrothermally active region situated on the boundary of the converging Pacific and Australian plates north of New Zealand, is host to a chain of underwater volcanoes, many of which are both volcanically and hydrothermally active. Rumble II West, located at 35°21.200’S, 178°39.100’E, is one of thirteen volcanoes located on the southern 260 km of the Kermadec arc and before this survey, it had yet to be mapped in detail. Rumble II West is important because it supports rare and unique hydrothermal ecosystems and contributes to deep ocean heat and chemical fluxes. In addition, valuable minerals like sulfides and even gold have been dredged from it. Data was collected aboard the R/V Thompson in March 2009. Bathymetric surveys and camera tows of the seafloor were used to determine the geological evolution of Rumble II West. Results from these analyses indicate that Rumble II West is a post-erupted stratovolcano that has undergone multiple caldera formations and ring faulting. In addition, the volcano has experienced tectonic faulting through the main structure, oriented NE to SW, that demonstrates the buildup of geologic stress created by subduction of the tectonic plates that form the arc.