A global Earth Magnetic Anomaly Grid (EMAG2) was compiled from satellite, ship and airborne magnetic measurements. (Maus et al., 2009) Over the continents and the Arctic we made use of exisiting magnetic anomaly grids, whereas original ship and airborne trackline data were processed over the rest of the oceans, wherever available. CHAMP satellite magnetic measurements provided the magnetic field at wavelengths above 330 km. The EMAG2 grid is available at http://geomag.org and http://ngdc.noaa.gov. Directional gridding Due to the sparsity of magnetic field measurements in the southern oceans, it is necessary to interpolate the magnetic field between tracklines. Our interpolation algorithm takes the direction of the magnetic lineations into account. Tje lineations are parallel to the isochrons, which are perpendicular to the gradient of the age of teh oceanic crust. We use the age grid of Müller et al. (2008). The magnetic field ad a given grid point is computet by Least Squares Collocation from the surrounding measurements. If the point is on land, we use an isotropic correlation function with Rc = 14 km correlation length. Over the oceans we use Rc = 56 km parallel to the isochrons and Rc = 14 km in the spreading direction. Measurements seperated from the grid point by an age discontinuity or a topographic feature are excluded from the collation.

Onshore geological field work combined with an onshore/offshore aeromagnetic survey was carried out during a joint expedition of the German BGR and the Canadian GSC to understand the structural architecture of the North American continental margin. The helicopter-borne magnetic survey of 2008 covered the northern coastal areas of Ellesmere Island and the adjacent marine areas. The survey was conducted with a line separation of 2 km and covered a 40 to 50 km wide swath offshore about parallel to the north coast of Ellesmere Island from Yelverton Bay in the west to Parr Bay east of Cape Columbia, the northernmost point of Canada. Between Yelverton Bay and M'Clintock Inlet, the survey extended about 40 to 50 km inland, which was the prime target area of the CASE 11 geological investigations. This section of mountainous terrain was flown in a “draped” mode to keep the distance to ground at approximately 1500 ft, same as over the offshore areas. During a 4-weeks period in May/June 2008, close to 8000 km of aeromagnetic line data were acquired, covering an area of 12000 km².

The BGR Antarctic cruise 1996 from 29th December 1995 to 6th February 1996 with M.S. AKADEMIK NEMCHINOV was designed to acquire new marine geophysical data for a better understanding of the geological processes, timing, occurrence and location of rifts of the initial break-up of southern Gondwanaland. A total of 3,836 km of multichannel seismic reflection data have been collected in the areas of the Cosmonaut Sea, the Astrid Ridge, the Lazarev Sea and the southern Agulhas Plateau in parallel with magnetic and gravity measurements. In addition magnetic and gravity measurements were carried out on transit. Major new observations of the collected MCS data include: (1) Volcanic rocks play a major part in the construction of the Astrid Ridge and also of the Agulhas Plateau. (2) The early opening of the Lazarev Sea was associated with excessive volcanism resulting in the emplacement of a voluminous volcanic body characterized by an internally divergent pattern of seaward-dipping reflectors. (3) The Astrid Fracture Zone continues in form of a sediment-filled basement depression flanked by distinct basement highs into the Lazarev Sea, and apparently swings to the west parallel to the coast of Queen Maud Land. (4) The thickness of sediments in the Cosmonaut Sea overlying oceanic crust of inferred Early Cretaceous age is in excess of 4s (twt), i.e. about 6,000 m. Three regional seismic markers of inferred Cretaceous, Late Eocene-Oligocene and Middle Miocene ages subdivide the sedimentary column.

As part of the PMAP-CASE (Polar Margin Aeromagnetic Program - Circum-Arctic Structural Events) expeditions, two surveys were conducted in consecutive seasons in 1997 and 1998. Cooperating partners were the Department of National Defence (DND), GSC Ottawa and the Institute for Aerospace Research Ottawa (IAR-NRC). The surveys covered the areas of the northern continental margin of Greenland including the northern Nansen Land and western Johannes V. Jensen Land, as well as parts of the Lincoln Sea. The objective of the campaigns was to investigate the structures of the upper crust of the Morris Jesup Plateau and the correlation of magnetic anomalies with known structures and geologic units on land (Franklinian Basin, Kap Washington volcanics, and volcanic dyke swarms). Airborne magnetic surveys (Convair 580) were conducted with a 3 km flight line spacing, and control lines were flown every 30 km. Data were recorded at a constant flight altitude of 300 m above ground. Approximately 30000 km of line data were collected during the two expeditions, covering an area of 73000 km².

As part of the expedition CASE 20, geological fieldwork and an aeromagnetic survey were conducted in order to study the architecture and structure of the present continental margin of Northeast Greenland. The helicopter-borne magnetic survey in July and August 2018 covered the coastal areas between Independence Fiord and Kronprins Christian Land. During a 2-weeks period nearly 6500 km of aeromagnetic line data were collected covering an area of 17000 km². The distance between the individual lines was 4 km and control profiles were flown every 20-30 km. The aeromagnetic data were recorded by a magnetometer, which was towed approx. 30 m beneath the helicopter.

Regarding the use of renewable energy and the reduction of greenhouse-gas emissions, the geological storage of fluids is of particular interest. Therefore, reservoir and barrier formations in the German North Sea come into focus. Due to the widespread distribution of storage and barrier rocks at suitable depths and in combination with a relatively low tectonic overprint, the West Schleswig Block region in the German North Sea shows a high prospectivity for CO2 storage. By means of this high-resolution 2D reflection seismic survey, we want to investigate the potential impairment of geological barriers at the top of geological storage formations (i.e. claystones/mudstones and salt of the Upper Buntsandstein, mudstone dominated formations of the Lower Cretaceous and of the Tertiary). The seismic acquisition setup with a 2400 m active streamer cable with 384 channels will allow a precise image of near-surface structures, such as Quaternary channels, seismic pipe structures, chimneys, polygonal fault systems and crestal faults. In the time period between Nov. 13th and Nov. 24th we acquired 32 lines 2D seismic reflection data (about 1500 km in total) in combination with gravity data, multibeam data and sediment echosounder data. The seismic data resolve the sediments from the seafloor down to the base of the Zechstein. With the acquired data, the sediments of the Mesozoic and Cenozoic up to the seafloor (2-3 seconds of twoway-traveltime) will be imaged in high-resolution for the first time. The imaged fault systems will be investigated regarding their ability to build seal bypass systems. In addition, we acquired seismic data across the Figge Maar blowout crater and we intend to compare these data with the seismic data from the West Schleswig Block.

The structure and tectonics of the Pacific margin of Costa Rica were studied by multichannel seismic measurements in parallel with gravity measurements and swathmapping from the Cocos Ridge to Nicoya Peninsula during R/V SONNE cruise SO81 legs 1 and 2 from 18th August to 15th September 1992. In addition geological sampling has been carried out. Dominant structural feature is the buried Costa Rica Terrrane (CRT), a complex and segmented, wedge-shaped unit characterized by relative high seismic velocities of 4 km/s. The thickness of this several tens of kilometres wide zone varies between 0.5 and 3 s (twt). The CRT forms the backstop against which the sediments of the subducting Cocos plate accrete resulting in accumulation of sedimentary mass beneath and in front of the CRT, as well as in simultaneous uplift and fracturing of the CRT. It appears that the distinct CRT is affected locally by raft tectonics, i.e. a form of thin-skinned extension by normal faulting from gravity sliding over a non-stretched oceanic crust. A unit is recognizable between the base of the CRT and the surface of the subducting oceanic crust on most of the seismic lines. This unit is thought to consist mostly of ductile pelagic to hemipelagic shales. Some segment boundaries of the CRT are associated with morphological furrows, 5 to 10 km wide and up to 30 km long running across the slope. We feel that the data acquired during SONNE cruise SO81, and the preliminary results at hand have already improved our knowledge on the geological processes of active continental margins. We are convinced that plausible concepts for the origin of tsunamis and asperities can be developed on the basis of the data collected during SONNE cruises SO81 and SO76. The research of both SONNE cruises are a contribution to the International Decade of Natural Desaster Reduction (IPNDR).

On the F.S. POLARSTERN cruise ANT-IV/3 (6th December, 1985 - 13th March, 1986) multichannel seismic measurements were carried out in parallel with magnetic and gravimetric measurements on 33 lines with a total length of 6,263 km. 3,350 km of the multichannel seismic lines have been processed aboard. The geophysical studies were designed to investigate the structure and geological development of the Weddell Sea continental margin from meridians zero to 60°W, and to define suitable and safe drilling locations for Leg 113 of the Ocean Drilling Program. The main results of the geophysical studies are: (1) The discovery of an approximately N50°E trending failed drift basin, following the trend of a negative magnetic anomaly and a positive gravity anomaly. (2) The discovery of two extensive wedge-shaped and symmetric basement units around a failed drift basin between longitudes 40°W and 20°W. The seismic characteristics, i.e. seismic velocities of 4 km/s and an internally divergent pattern of reflectors suggest that both wedges are formed from extrusive/intrusive volcanic rocks. (3) The confirmation of a major plate tectonic boundary trending approximately N80°E to N60°E, i.e. the EXPLORA-ANDENES escarpment. (4) The confirmation of a glaciogenic progradational wedge beneath the shelf of the Weddell Sea Embayment, made up of several thousand metres of sediments. (5) The definition of 13 suitable and safe drilling locations for ODP-Leg 113.