The AWI Network Antarctica - Alfred-Wegener Institute, Germany

Tanja Fromm, Alfons Eckstaller and Jölund Asseng report on the AWI network in Antarctica for the Summary of the Bulletin of the International Seismological Centre

Towards a self-sufficient mobile broadband seismological recording system for year-round operation in Antarctica

Passive seismic measurements allow the study of the deeper Earth beneath the thick Antarctic ice sheet cover. Due to logistical and weather constraints, only a fraction of the area of the Antarctic ice sheet can be surveyed with long-term or temporary sensors. A fundamental limitation is the power supply and operation of the instruments during the polar winter. In addition, there is only a limited time window during the field seasons to deploy the stations over the year. Here we present a rapidly and simple deployable self-sufficient mobile seismic station concept. The station consists of different energy supply modules aligned according to the survey needs, measuring duration, and survey aim. Parts of the concept are integrated into an already existing pool of mobile stations and in the seismological network of the geophysical observatory at Neumayer III Station. Other concepts and features are still under development. The overall goal is to use these temporary mobile arrays in regions where little is known about local and regional tectonic earthquake activity

The role of Antarctic overwintering teams and their significance for German polar research

Germany has been operating permanently crewed research stations in Antarctica for more than 45 years. The opening of the Georg Forster Station (1976) and Georg von Neumayer Station (1981) initiated a period of continuous environmental monitoring that allowed both the former East Germany and West Germany to become contracting parties in, and achieve consultative status with, the framework of the Antarctic Treaty. This marked a milestone in German polar research. Continuous research at the Neumayer Station III, its two predecessors, and the now-dismantled former German Democratic Republic (GDR) Georg Forster Station is undertaken by teams of so-called "overwinterers", presently with nine members, who stay at the base for longer than an entire Antarctic winter. Their long-Term stay in Antarctica is defined by isolation, separation from civilization, routine work to sustain long-Term scientific observations, and unique personal experiences. This article is dedicated to them and outlines their part and role in the German Antarctic research landscape

The role of Antarctic overwintering teams and their significance for German polar research

Germany has been operating permanently crewed research stations in Antarctica for more than 45 years. The opening of the Georg Forster Station (1976) and Georg von Neumayer Station (1981) initiated a period of continuous environmental monitoring that allowed both the former East Germany and West Germany to become contracting parties in, and achieve consultative status with, the framework of the Antarctic Treaty. This marked a milestone in German polar research. Continuous research at the Neumayer Station III, its two predecessors, and the now-dismantled former German Democratic Republic (GDR) Georg Forster Station is undertaken by teams of so-called “overwinterers”, presently with nine members, who stay at the base for longer than an entire Antarctic winter. Their long-term stay in Antarctica is defined by isolation, separation from civilization, routine work to sustain long-term scientific observations, and unique personal experiences. This article is dedicated to them and outlines their part and role in the German Antarctic research landscape

Neumayer III and Kohnen Station in Antarctica operated by the Alfred Wegener Institute

The Alfred Wegener Institute operates two stations in Dronning Maud Land, Antarctica. The German overwintering station Neumayer III is located on the Ekström Ice Shelf at 70°40’S and 08°16’W and is the logistics base for three long-term observatories (meteorology, air chemistry and geophysics) and nearby research activities. Due to the vicinity to the coast (ca. 20 km from the ice shelf edge), the Neumayer III Station is the junction for many German Antarctic expeditions, especially as the starting point for the supply traverse for the second German station Kohnen.The summer station Kohnen is located about 600 km from the coast and 750 km from Neumayer III Station on the Antarctic plateau at 75°S and 00°04’E. It was erected as the base for the deep-drilling ice core project, which took place between 2001 and 2006. Since then Kohnen Station is used as a logistics base for different research projects

Antelope in Antarctia

Antelope Software is used at Neumayer Station for real time data aqcuisition of seismic data

Investigations of Crustal Structures beneath Dronning Maud Land

The western part of Dronning Maud Land (DML), Antarctica, principally consistof the Archean Grunehogna Craton and the Grenville-age (1.1 Ga) Maud Province(Jacobs, 1991). Most of the area is covered by ice. Outcrops are the mountainranges Heimefrontfjella, Kirvanveggen and Sverdrupfjella. These are the westernparts of the East Antarctic Orogen, the southern continuation of the EastAfrican Orogen, formed during the collision of East and West Gondwana(Pan-African orogenesis, ca 550. Ma).The Heimefrontfjella metamorphic complex is splitted by the Heimefront shearzone. This steeply dipping and NE trending dextral shear zone separates tworegions with a different tectonic history: the Vardeklettane and Kottas terranewith Grenvillian crust at the NW side and the Sivorgfjella Terrane with strongPan-African tectono-thermal overprinted crust at the SE side of the shear zone.(Golynsky & Jacobs, 2001)The structure of the crust and mantle in western DML is mostly unknown.Especially the deeper crustal fabric along the geological boundaries is ofgreat interest. Thus, during the Antarctic summer 2002/2003, a temporaryseismometer network consisting of five seismometers was installed along a 250km line crossing the Heimefrontfjella shear zone. In addition a permanentbroadband seismometer station at Kohnen Station (ca. 75°S, 0°E) wasestablished. In combination with registrations from the Neumayer seismometernetwork and the seismometer at the South African SANAE IV Station, a spatialmapping of crust thickness (Moho depth) by means of calculating the receiverfunctions will be obtained. Further analysis of the data will yield to therecent/past strain/stress distribution (seismic anisotropy) and the detectionof local seismicity.Preliminary results (Eckstaller, et al., 1991) from a analysis of a refractionseismic profile, perpendicular to the shear zone, are showing different regionsof crustal thickness: in the north-west 42 km and in the south-east 50 km. Thisconfirms that the Heimefrontfjella shear zone is also a boundary in terms ofcrustal evoloution and fabric. The interpretation of this seismic profiletogether with new obtained aerogravity, aeromagnetic and ice thickness data incombination with the seismological data will provide a 3-D model of the crustalstructures beneath western Dronning Maud Land.ReferencesJacobs, 1991, Berichte zur Polarforschung 97Golynsky & Jacobs, 2001, The Journal of Geology, vol. 109: 136-142Eckstaller, et al., 1991, Berichte zur Polarforschung 86: 108-12