2016-2017 USAP Field Season
Mantle structure and dynamics of the Ross Sea from a passive seismic deployment on the Ross Ice Shelf
Dr. Douglas Wiens
Supporting Stations: McMurdo Station
Last austral summer this research project deployed 18 broadband seismographs across the Ross Ice Shelf (RIS) to constrain the seismic structure associated with the Ross Sea extension. The presence of the RIS provides an outstanding opportunity to instrument this region without the expense and logistical issues associated with ocean-bottom seismograph deployments in polar regions. Previous deployments of broadband seismographs on the RIS show that seismic P waves and Rayleigh waves can be well-recorded despite the underlying ice and water layers, permitting P-wave and surface-wave tomography and noise-correlation studies. Tomographic models developed from these data will be used to choose between competing models for the dynamics of the Ross Sea. In particular, researchers will investigate whether low-velocity hot mantle is localized in the vicinity of Ross Island and the Marie Byrd Land dome. Alternatively, a broad region of hot mantle, including the Eastern Ross Sea, would indicate distributed recent tectonic activity and call into question models stating that Eastern Ross Sea extension largely ceased during the Mesozoic. The data will also allow researchers to investigate the deeper structure (greater than 200 kilometers) to evaluate the possible role of mantle plumes and/or small-scale convection in driving regional volcanism and tectonism across the region.
Field Season Overview
This season, the field team will be based out of two small field camps; one on the Ross Ice Shelf, the other at Siple Dome. They will use a combination of fixed-wing support (Basler, Twin Otter, and LC-130 aircraft) to return to the 18 seismic sites installed in 2014. They will remove the stations and all associated materials for retrograde to the US.
Deploying Team Members