TROLL: A New, Very Broadband Seismic Station in Antarctica

Abstract

Most of the Antarctic continent is covered by a thick ice sheet, and consequently seismic stations in this region are often installed on ice. This can be problematic because the seismic stations then move along with the dynamic ice sheet; and, in addition, the thick ice layer disturbs the pulse shape of seismic signals due to reverberations. The horizontal movements can be tracked with the Global Positioning System (GPS) clocks of the data loggers and station coordinates can be corrected for; however, in particular, the horizontal components of seismic sensors are dependent on a stable horizontal leveling. To accommodate the ice movements, the sensors have to be leveled quite often, which makes a proper permanent operation dependent on regular maintenance. During the Antarctic summer season of 2011–12 and in collaboration with the Norwegian Polar Institute (NPI), NORSAR installed a new, very broadband, three‐component seismic station in the vicinity of the Norwegian Antarctic Research Base Troll, located on the Jutulsessen nunatak in Dronning Maud Land in context with the activities of the Norwegian Antarctic Research Expedition 2011–2014. Prior to the installation of the new station, the permanent network in Dronning Maud Land (see Fig. 1) consisted of three broadband stations and a small aperture array in the vicinity of the German Antarctic Station Neumayer III (VNA1; VNA2, which is the central element of a not shown short‐period seismic array; and VNA3) and one station at each of the Antarctic research stations Aboa (Finland, ABOA), Sanae IV (South Africa, SNAA), Maitri (India, MAIT), and Novolazarevskaya (Russia, NVL). The station SNAA jointly operated by South Africa and the GeoForschungsZentrum in Potsdam is one of the auxiliary stations of the International Monitoring System (IMS) for monitoring compliance with the Comprehensive Nuclear‐Test‐Ban Treaty (CTBT). Seismic data from TROLL, Neumayer III, and SNAA are accessible in …