Analysis of GNSS Time Series Recorded on South Shetland Island and Antarctic Peninsula during the Geodynamic Activity in 2020 of the Orca Underwater Volcano (Brandfield Sea Rift, Antarctica) †

Abstract

The region defined by the South Shetland Islands, Bransfield Sea, and Antarctic Peninsula has complex geodynamic activity resulting from the active subduction process of the Phoenix Plate under the Antarctic Plate. This subduction produces a rift of expansion along the Bransfield Sea basin between the South Shetland Islands and the Antarctic Peninsula. There is also a chain of submarine (Orca, Three Sisters, and Building A) and emerged (Deception and Pinguin) volcanoes. In 2020, there was intense seismic activity around the Orca volcano with earthquakes of up to 6.9 Mw. This paper presents displacement models of this seismic activity produced in the region. The geodetic time series of the GNSS stations located in the region were analyzed: UYBA at the Uruguayan Artigas Antarctic Base (King George Island) and PAL2 at the U.S. Palmer Antarctic Base (Anvers Island). These data were taken from the Nevada Geodetic Laboratory.